Gold placers and placering in Arizona |
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GOLD PLACERS AND PLACERING IN ARIZONA by Eldred D. Wilson Bulletin 168 Reprinted 1981 - State of Arizona Bureau of Geology and Mineral Technology Geological Survey Branch A Division of the University of Arizona PREFACE TO BULLETIN No. 142 .... Copyright © 1961 The Board of Regents of the Universities and State College of Arizona. All rights reserved. TABLE OF CONTENTS PAGE PREFACE 8 PREFACE TO BULLETIN No. 160 . 8 9 PART I ARIZONA GOLD PLACERS GENERAL FEATURES OF GOLD PLACERS ...........................•.........•...........•....... _... 11 Origin 11 Distribution of Arizona gold placers.................................................... 12 Relatipn to pediments 12 Relation to streams 14 Relation to geology and types of veins.................................................. 14 Yearly rainy seasons of Arizona.............................................................. 15 HISTORY OF ARIZONA GOLD PLACER MINIm;.................................................... 15 Summary 15 Early production 15 Production after 1900 16 YUMA COUNTY ....•...................•.............•.•.••••...•••••••.••.••••.••••••..••..••••••••.•••••••••••••••• 18 Districts 18 Production 18 Gila City or Dome placers 18 I, aguna placers 21 Muggins placers 22 Castle DOIne placers 23 Kofa or S. H. placers.................................................................................. 23 Tank Mountains placers 24 Trigo placers 25 La Paz placers 25 Plomosa. district 29 La Cholla placer area 29 Oro Fino placer area 30 Middle Camp placer area 31 PIOlnosa placer area 31 Harquahala placers 32 MOHAVE COUNTY ............•...................••.........•...........•••.•.••..•.••...•......•........•..••••..• 32 Districts and production 32 Chemehuevis placers 32 Silver Creek placers 33 Lewis placer 33 Lookout placers 34 Wright Creek placers 34 Colorado River placers 34 Gold Basin placers 35 IGng Tut placers 37 YAVAPAI COUNTY ••.......................•......••.•••..•.••••..•••.•.••_ ••••••••••••....••. _................... 38 Introduction 38 Early History 38 Production 39 Arizona Geological Survey The Arizona Geological Survey ( AZGS) became an independent State agency July 1, 1988 in accordance with Senate Bill 1102, which was enacted in 1987. The purpose of the AZGS - to assist the wise use of lands and mineral resources in Arizona by providing scientific and investigative research and information - was essentially unchanged. The ancestral AZGS began in 1881, when the Office of the Territorial Geologist was established by the Territorial Legislature. The primary duties were to collect and provide information about mineral resources. In 1893 the University of Arizona established a testing laboratory, known informally as the " Bureau of Mines." From then until statehood in 1912, Territorial Geologists were also affiliated with the " Bureau of Mines" and the university. A 1915 statute formally established the Arizona Bureau of Mines as a State agency administered by the University of Arizona, continuing, essentially unchanged, the functions of the " Bureau of Mines" and. the Territorial Geologist. Data collection and research activities continued to be · concentrated on mineral resources. Sixty- two years later, in 1977, the Bureau's enabling legislation was modernized and its name was changed to the Arizona Bureau of Geology and Mineral Technology. It continued to be administered as a diVision of the University of Arizona. The Bureau was charged with investigating geologic hazards and limitations, as well as the geologic framework and mineral resources of Arizona, in anticipiltion of population growth and increased competition for and conflict over land, mineral resources, and water. The AZGS publishes maps, books, and reports, which are available for inspection at the AZGS office in Tucson and may be purchased through the mail. The AZGS office includes a library that is open to the public during normal working hours. Arizona Geology, published quarterly by the AZGS, contains summaries of AZGS research, announcements of new publications and theses, and short, generalinterest articles on the geology of Arizona. To obtain copies of this publication, contact the Arizona Geological Survey, 845 N. Park Ave., Tucson, AZ 85719; ( 602) 882- 4795. 12- 88UASOO/ 1839 GOLD PLACERS AND PLACERING IN ARIZONA Arizona Bureau of Mines* Bulletin 168 1961 ( reprinted 1981 and 1988) " currently the Arizona Geological Survey ~ e~~ e; r:~~ tifc~ r~ Ii" ii"'" i~~~~~''''''''''''''''''''''''''''''''''' . ~~~:~;~:~~~~~ fi::=~ · :::~:::::::::::::~::::~::~~~::::::::::::::::::::::::::::::::::::::::::::::::::::: Groom Creek placers __ __ _._.~~~~~~~:~:~::::~:~::~:~~::::~~~:~~:~:~:~:.~ .. Walnut Grove placers . Minnehaha placers . ~~~~ l t~~~ e:~ p" i~~~~~ :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Granite Creek placers ,. Eureka placers . Humbug placers .. other Yavapai placers ::::: , 39 43 46 48 52 52 54 55 55 56 56 57 57 57 SANTA CRUZ COUNTY 81 Production 81 Oro Blanco placers 82 Patagonia or Mowry placers 83 Harshaw placers 83 Tyndall placers 83 Nogales placers 84 Palmetto placers 84 COCONINO, NAVAJO, AND APACHE CoUNTIES , · .. · · .. · · · · · · · · · · · · · · · · · · · · · · · 84 REFERENCES CITED IN PART I 85 PINA~ t~~ J~~ ro~ · · · :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~ anada del Oro or Old Hat placers 61 GRAHAM COUNTY 65 ~ fad~ i~~~ pi";;~.~~~........................................................................................ 65 ...................................................................................... 65 G, u ~~~~:~ i~ J~;;~~~-~_ •-. i! Payson placers 63 ...................................................................................... 64 PART II 90 87 87 87 87 88 88 88 88 88 89 89 87 SEEKING PLACER GOLD ....,. --_ ~ ~ .. , ~ , - -.. SMALL SCALE GOLD PLACERING FACTS ABOUT GOLD . Identification of placer gold , . Color . Specific gravity . Mallea bility and ductility . Solubility . Physical properties of gold . Gravity concentration . Amalgamation . Interfering factors . Size of gold particles . INTRODUCTION . 58 58 58 59 60 61 MARICOPA COUNTY -- - ---.-- _-.-.- . t~! t~~~~~~~~ · ~~~~~~::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Hassayampa placers . Other Maricopa County placers :::::::.:::::::::::::: GREENLEE COUNTY 65 CPrloifdtounc- tiMonorenci , placers . 65 ............................................................................ 65 COCHISE COUNTy .................._- -_ . E1;~~~ i~~~ c~~~~~;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: . g~ fJh~~~ chl~ l~ cse~ · · · ~ i;~~~::: ii:~~~ i~::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~:~~~ n J~~~~ rs : ~:::::::::::::::::::::::::::::::::::::::::::::::::::::::: ••••• _ •• _ _. _' ••• ' u ~.~~ •••••••••• ~ •••• ~ •••••••• ~ •••• ~ •••• PIMA COUNTY .......~~ ~"' ..~ ..~~~ ~ ~ ~.~ ~ _ . Production ~! j~~~~ r;~~~~~~~ i::~~~ i~~~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~~ a: l~: A~:~~ t~ · · Pi"~~~~~ · · · · · · :::::::::::::::::::::::::::::::::::::::::::::::::::::::: . ~~ oa;~~: rl~ f:~: r~ · · · · · · · · · · · · · · · · · :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~~:~ ~:~ o~ o~~~~ er~;~~~~~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 67 67 67 69 69 70 70 71 71 71 72 77 78 80 80 80 81 81 81 PLACER EQUIPMENT AND METHODS 91 Gra\' ity concentration 91 Panning Utensils 91 Pan, miner's 91 Batea 91 : Miner's spoon 92 Other panning utensils 92 Panning 92 Cleaning concentrates 93 Amalgamation 93 Copper amalgamating pans 94 Instructions for amalgamating copper pans 94 Panning with an amalgamated pan 94 Quantity of gravel that can be panned in eight hours............ 96 Rocker ( Cradle) 96 Capacity 96 Construction details 96 Apron 98 Riffles 98 Hopper or screen box ,....... 98 Slope of bottom 98 Amalgamation 99 APPENDIX SUGGESTED LIST OF EQUIPMENT FOR PROSPECTING IN THE SOUTHWEST 118 Prospecting tools 118 General camping equipment 118 Cooking equipment 118 Medical and first- aid supplies 118 ~ l~~_ t~::.~~:::~~~~:~:~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 1~~ Construction details for knock- down rocker 100 The Long Tom ...................•............................•.............::::::::::::::::::::::::.::::: 100 Operation : : 101 Sl uic~ 1ffl~~ :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: i~~ Slope 104 Water consumption and capacity 104 Amalgamation ....•................................................................................. 105 Clean- ups 105 Small sluices ..........................•............................................................. 105 Wet Methods vs. Dry Methods 107 Dry Concentration 108 Dry Concentrators 109 Blanket 109 Dry panning and blowing 109 Dry- washers 109 Separating Gold from Golci Amalgam III Retorting III Retorts III Charging an amalgam retort 112 Potato method 114 Nitric acid method 115 TABLES AND CONVERSION DATA....................... 116 ILLUSTRATIONS 51 36 38 40 45 46 49 53 60 68 95 103 110 113 13 14 24 27 74 92 92 92 97 101 105 106 107 112 VI.- GOLD STAR COMPANY PLANT, COPPER BASIN . 6. - PAN, GOLD MINEH'S 14. - LONG TOM PLATE FIGURE PLATE VII.- AINLAY BOWL CONCENTHATOR, PANTLE BROS. LEASE, BIG BUG CHEEK . PLATE VIlI.- NUGGETS FROM YAVAPAI COUNTy . PLATE lX.- TypICAL PLACER WORK ON SAN DOMINGO WASH · · · · · PLATE XIlI.- DRY- WASHER . PLATE XIV.- RETOHT ( HOMEMADE) . FIGUHE 1. - INDEX MAP SHOWING LOCATION OF ARIZONA GOLD PLACEHS FIGURE 2. - IDEAL CHOSS- SECTIONS OF MOUNTAIN PEDIMENTS . FIGUHE 3 - GEOLOGIC MAP OF KOFA OR S. H. PLACER AREA.. PLATE X.- GOLD GULCH MINING COMPANY OPERATIONS, TEVISTON DISTRICT . PLATE XI.- ROCKER IN OPERATION . PLATE.. XII.- SMALL SLUICE IN OPERATION . FIGUR~; 7. - BATEA FIGUHE 8. - SPOON, MINER'S . FIGURE 9. - ROClU; R, KNOCKDOWN . PLATE L- MoTOR- DHIVEN DRY- WASHER, SEARLES GROUP, GOLD BASIN PLATE Il.- SAMpLING OPERATIONS IN KING TUT PLACERS . PLATE IlI.- DREDGING OPERATION ON LOWER LYNX CREEK. . PLATE IV.- TypICAL GRAVELS OF WEAVER CREEK PLACERS . PLATE V.- Top OF RICH HILL . FIGUm: 4. - GEOLOGIC MAl' OF pAHT OF DOME ROCK AND PLOMOSA MOUNTAINS . . FIGURE 5. - GEOLOGIC MAP OF GHEATERVILLE PLACER AREA .. FIGUHE FIGUHE 11. - RIFFLES . FIGUHE 13. - SLUICE LAY- OUT FIGURE 14. - RETOHT FIGURE 12. - SLUICE BOX, SMALL . 116 116 116 116 117 117 Troy weights and equivalents........... . . Troy weights and measures . Equivalents . Liquid volume and capacity equivalents . Weights of materials . PART III SELLING GOLD . OpEHATIONS DURING 1951- 1961 119 ARIZONA PLACER PRODUCTION 1951- 1959................................................... 120 INDEX 121 PREFACE Although the yield from placers in Arizona has been relatively small through the past several years, public interest in gold increased greatly in 1960, and the Arizona Bureau of Mines now receives numerous requests for information concerning this precious metal. The Arizona Bureau of Mines Bulletin No. 160, Arizona Gold Placers and Placering, Fifth Edition, Revised, was published in 1952. However, it has not been available for general distribution since 1959. This present Bulletin No. 168 supersedes Bulletin No. 160 in the publication series of the Arizona Bureau of Mines inasmuch as it represents a thorough modification of the subject matter of the earlier bulletin and, also, it contains supplemental information which serves to bring statistical data up to date. J. D. Forrester Director October, 1961 PREFACE TO BULLETIN NO. 160 The Arizona Bureau of Mines Bulletin No. 142, ARIZONA GOLD PLACERS AND PLACERING Fourth Edition which W3S written in 1933 and republished in 19: 31, has been out ' of print for the past two years. For 1932 to 1950, the output of placer gold in the State was more than d? uble the amount produced during 1900- 1931. Owing pa~ tly to thIS fact and partly to a public interest in gold, the ArIzona Bureau of Mines continues to receive numerous requests for information regarding placers. This Bulletin No. 160 represents a revision of the Bulletin No. 142, with addition of data from the U. S. Bureau of Mines Minerals Yearbooks and material accumulated by the Arizona Bureau of Mines. T. G. CHAPMAN PREFACE TO BULLETIN NO. 142 The first publication of the Arizona Bureau of Mines on Arizona Gold Placers was written by M. A. Allen and appeared in 1922 as Bulletin 118. It was mainly a compilation of data already in print, but scattered and difficult to find. The stock of this bulletin was exhausted in four years. Eldred D. Wilson, Geologist with the Bureau, was then commissioned to rewrite the bulletin, adding what new data could be obtained. Assisted by W. R. Hoffman in the field and further aided by the advice and suggestions of Carl Lausen, then Geologist with the Bureau, Mr. Wilson completed his work in the summer of 1927, and a large edition was published at once as Bulletin 124. Conditions with which everyone is familiar developed within two or three years, and so much interest was shown in gold that the demand for this bulletin was extremely heavy, and the supply was exhausted before June of last year. A new and greatly enlarged bulletin, No. 132, was prepared at that time, and, although five thousand copies were printed, they have all been distributed. The present bulletin does not differ radically from No. 132, but many parts of that bulletin have been rewritten and an attempt has been made to bring the information obtained therein up to date. Eldred D. Wilson made the field investigations required to secure this new data, and at least a dozen additional districts are described in the present bulletin. Part II has been presented by G. R. Fansett to thousands of people who have attended short courses for gold prospectors, which he has conducted in centers of population all over the State during the past year or two, and experience has shown that the information conveyed is very useful, especially to inexperienced persons. With the exception of very recent discoveries, in spite of diligent efforts to gather all the information available, the descriptions of Arizona placer fields are incomplete and otherwise unsatisfactory. It could, however, hardly be otherwise. The pioneer prospectors and miners were too busy overcoming obstacles, struggling against hardships and celebrating occasional periods of good fortune to write about their experiences, even if able to do so. Few authentic records of most of the earlier camps exist. Available statistics are often far from reliable, and good judgment is required to separate the true from the' false. Anyone who secures a copy of this bulletin with the idea of obtaining therefrom such data as will enable him to engage profitably in placer mining in Arizona should remember that gold placers are usually the first deposits found and exhausted in every region. Prospecting for placer gold is not expensive, and a deposit once found can be worked with little capital unless dredging is necessary. Even hydraulic operations ( which are not described in this bulletin because it is doubtful if any deposits that can be worked satisfactorily in this way exist where the ~ equisite water is ~ vailable) do not ordinarily require the expendIture of a! ly consIderable sum for equipment unless the water must ~ e pIped or flumed long distances. Because placer gold can ~ e easIly and cheaply recovered where water is available, it is not lIkely that unworked ground of fairly good grade remains, at least al~ ng streams which flow for several months a year. People attemptmg to do placering in such districts must therefore ordinarily be satisfied to work ground where the' difficu1tie~ encountered, such as the prevalence of huge boulders, were too great or the grade of gravel was too low to attract the old- timers. Hundreds of people are, however, trying to earn wages on such ground now. Although there is undoubtedly much placer gold in the socalled " desert" regions of southern Arizona the lack of water both for placering operations and for use in the camp, is a seriou~ ? rawback there, as are also the cemented conditions of the gravel m several areas. Many types of dry- washers have been tried in these regions, usually with very indifferent success for reasons outlin. ed in this bulletin, and the high summer temperatures that pre- yaII there should deter anyone from prospecting in these areas durmg the summer months unless he is accustomed to the conditions he will encounter and knows how to meet them. Recent field investigations made by Eldred D. Wilson reveal the fact that the average daily recovery of each experienced pla~ er . miner ~ n the State is probably less than a dollar a day, whIle mexperIenced persons are averaging less than 25 cents a day. Of cour~ e these statements m~ an that a few are doing fairly well, a larger .!?- umber are earnmg expenses, and the majority are not recovermg en~) Ugh . gold to buy food. Rumors that good ~ ages can be made m thIS way, therefore, should be heavily dIscounted. A person not in robust health or one who has not sUfficien~ funds to fin~ nce his entire trip runs a splendid chance of starvmg to death If he tackles placer mining in Arizona. If, however, a man in good health is out of work, has enough money to pay camp e: x; pense. s fo~' some time, and is willing to work hard, a prospectmg tnp WIll doubtless prove preferable to lying around and doing nothing, but it should be taken with the full realization that it is highly probable that little gold will be found. Of cou. r: se, some ric~, virgin ground may be found, but the chance of makmg such a dIscovery is small. It is this chance, however, that has actuated all prospectors and led to the discovery of most mineral deposits. August 15, 1933 G. M. BUT'LER PART I ARIZONA GOLD PLACERS By ELDRED D. WILSON Geologist, Arizona Bureau of Mines GENERAL FEATURES OF GOLD PLACERS ORIGIN Gold placers, or deposits such as gravel and sand which contain notable concentrations of gold, all result from the slow milling and concentration processes incident to natural erosion of pre- existing gold- bearing rocks. The origin of many gold placers is traceable directly to auriferous veins, lodes, or replacement deposits which, in most instances, were not of high grade. According to Emmons, l placers are not apt to form from goldbearing outcrops that contain abundant manganese, iron sulphides, and chlorides, unless precipitating agents such as calcite, siderite, rhodochrosite, pyrrhotite, chalcocite, nepheline, olivine, or leucite are abundant, or unless erosion is very rapid. In other words, the gold may be dissolved and carried below by means of natural chlorination processes that are established when solutions containing chlorides, together with sulphuric acid from the oxidation of iron sulphides, act upon manganese dioxide; but this process is neutralized if precipitating agents are present, and may be ineffective if erosion is very rapid. According to Lindgren,~ the best conditions for concentration of gold into placers are found where deep decay of the rocks has been followed by slight uplift. As the rocks of a region break up under weathering, rainfall washes away most of the resultant detritus, grinds it by striking and rubbing it together and by dragging it along stream beds, and liberates most of the included gold. Because gold is six or more times heavier than ordinary rock. the liberated particles of gold will concentrate along the bottom and come to rest where the stream gradient lessens. The coarser particles will settle down first, and the fine and flaky gold will be carried farther along. The best placer concentrations probably occur in rivers of moderate ( about 30 feet per mile) gradient, under nicely balanced conditions of erosion and deposition. Except where gravel bars may form in slower reaches, particularly within the arcs of curves, very little concentration will take place in gorges. Such bars, through further deepening of the channel, may be left as elevated benches. Most of the gold in a placer generally rests on or near the bedrock. In some instances, the coarser gold is scattered through the lower 4 to 20 feet, or the gravel may be richest a few feet above bedrock, but never is the richness equally distributed IRefprences are listed numerically at end of Part 1. Figure I.- Index map showing lGlcation of Arizona gold placer districts. 40. Catiada del Oro. 41, Clifton- Morenci. 42. GUa River. 48. Alder Canyon. 44. Qu! jotoa. 46. Papago. 46. Armai'! l08a. 47. Old Baldy. 48. Greaterville. 49. LaB Guijns or Arivaca. 50. Tyndall. 51, Harshaw. 52. Patagonia or ' Mowry. Palmetto. 58. Nogales. 64. 01' 0 Blanco. 65. Tevistoll. 56. DOH Cabezas. 57. Pearce. rift Glee." on. 59. Gold Gulch ( Bisbee). 60. Huachuca. ----- I-----:-~ · _-\ I · I' ,, I · iI ,\ i · I 0' Ii - i_---,\' ! Fj I \ I" i" : r:' I ,~ ! 21. Granite Creek. 22. Lynx Creek. 23. Copper BlUlln. 24. Groom Cteek. 25. Big Bug. 26. Hassayampa ( Yavapai Couhty). 27. Model. 28. Placerlta. 29. Weaver. Rich Hill. 30. Minhehaha. 31. Black CanYon. 32. Humbug. 33. Vulture. 34. Hassayampa ( Maricopa County). 35. San Dominga. 36. Payson. 37. GlobL~' Miaml. : IH. Dd! lping Spring. 39. BUI · hnro~ 8a. p-------- I, ! -.....-....... -. -, i .............................. 1. Gila City ( Dome). 2. Laguna. 3. MugglnB. 4. Castle Dome. 6. Kofa or S. H. 6. ' rank Mountains. 7. Tri~ w. 8. Lu PIll.. 9. LI1 Cholla. Oro FIno. Middle Camp. 10. Plomosa. 11. Harquahala. 12. Chemehuevis. 13. Silver Creek. 14. Lewi:->. 16. Lookout. 16. Wri" hl Creek. 17. Willow Beach. IH. Gold Basin. In. King' Tut. 20. Ellft'lcn. 12 vertically. Among the best types of bedrock are compact clays, somewhat clayey, decomposed rock, and slates or schists whose partings form natural riffles. Smooth, hard material does not catch or retain the gold effectively. Gold works down for some distance into minute crevices of hard rock, for 1 to 5 feet into pores of soft rock, and for many feet along solution cavities of limestones. According to Lindgren, 2 crystallized gold, which is sometimes found in placers, indicates close proximity to the primary deposit. He states that there is probably no authenticated case of crystallized gold occurring in gravels which have been transported far, and that it is difficult to believe the assumption that such crystals are formed by secondary processes in the gravels. The high insolubility of gold in most surface waters is demonstrated by the fact that flake or flour gold, which commonly is in 3,000 particles per one cent's worth, may be carried by rivers of moderate gradient for hundreds of miles. The fineness, or parts of unalloyed gold per thousand, of placer gold is generally greater than that of the vein gold of the same district. This increase in purity, which is proportional to the distance that the placer material has been transported and to the decreasing size of the grains, has been shown to be due to solution and abstraction of silver by surface waters. DISTRIBUTION OF ARIZONA GOLD PLACERS Owing to the presence of gold- bearing rocks in most mountain ranges of the Southwest, gold placers which have been of economic importance occur in every county of Arizona except Apache, Coconino, and Navajo. As indicated on the accompanying map ( Figure 1), the placer districts of Arizona that have been notably worked are in the southwestern mountainous and desert half of the State. Many placers occur in gulches that issue from the numerous mineralized areas throughout this region. RELATION TO PEDIMENTS A pediment, as defined by Bryan, 3 is a more or less hilly plain, carved on solid rock and largely without alluvial cover, at the base of a desert mountain. The mountain slopes of a semi- arid region tend to have a steep profile. Most of the dissected basins or fiats that interrupt steep mountain slopes in this region prove, upon analysis, to be related to elevated pediments. The gold placers of Arizona, with the exception of a few that occur within mountain valleys or gulches, are related to pediments. The gold- bearing gravels occur not only in gulches and old channels which traverse or issue from pediments, but also, in many cases, as mantle upon the pediment itself. This relation may be explained as follows: As previously stated the best conditions for the concentration of gold into placers are where deep decay of the rocks has been followed by slight uplift. When removed by erosion, decayed rocks tend to liberate their heavy minerals within sufficiently short space to promote concentra- 14 Figure 2.- Ideal cross- section of mountain pediments. ( B) represents the effect of renewed uplift and long erosion upon ( A); the pediment of ( A) has been more or less dissected, and a newer one has been formed at the base of the mountain. tions. Undecayed rocks, on the other hand, are broken up by mechanical erosion which does not tend to release the heavy minerals with sufficient uniformity to produce placer deposits. In arid regions, mechanical erosion generally keeps ahead of notable rock decay on steep slopes but falls behind such decay on the the gentle slopes of pediments. RELATION TO STREAMS Most of the streams that have formed gold placers in Arizona were small, intermittent, and subject to torrential floods. Hence, placers of economic importance have been found to extend only for a relatively short distance downstream from mineralized pediment areas. Because of the intermittent character of the streams, many of the placers contain part of their gold more or less eratically distributed through a considerable thickness of gravel. In general, however, the richest material occurs at or near bedrock, especially where the bedrock surface forms natural riffles or contains irregularities such as potholes. Particularly along some of the larger streams, notable placers occur as elevated bars which were deposited within the inner arcs of curves. RELATION TO GEOLOGY AND TYPES OF VEINS The principal gold placers of Arizona are associated with areas of crystalline rocks, such as schist, granite, and gneiss, where the veins tend to be of the deeper- seated mesothermal and hypothermal types. 15 Gold- bearing veins of the shallow- seate. d or epithermal t. ype, which occur particularly in areas of volcamc rock, have not yIelded placers of notable economic importance. YEARLY RAINY SEASONS OF ARIZONA The advent of rain is of great importance to the placer miner in Arizona. It exposes nuggets and provides temporary water for wet methods of concentration, but it hinders the dry- washer, whose dirt must be dry. Usually in Arizona, as in much of the Southwest, the least rain falls in May and J~ ne . and the m? st during July, August, and the win~ er. Often thIS ram comes WIth local violence that fills arroyos WIth torrents. HISTORY OF ARIZONA GOLD PLACER MINING SUMMARY The original discovery of placer gold in Ariz. ona probably was made by Indians long before the advent of y. rhIte men. As early as 1774, according to Elliot's History of Anzona ( 1884), plac~ rs of the Quijotoa district, about 70 miles west o~ : rUCSOl:, were bemg worked extensively by Padre Lopez, a C~ strhan pnest. In 18? 8, according to Hamilton, 4 placers w~ r~ . dIscovered on the GIla River, about 20 miles east of where It Joms the Colorado, by Col. Jacob Snively. About 1862, La Paz placers, ; near the Colorado River about 65 miles north of Yuma, were dIscovered by Capt. Pauline Weaver. The greatly increased prospecting that followed these discoveries soon resulted in finding of the Dome Rock, Plomosa, San Domingo, and Yavapai County gold gravels. The Greaterville placers became known in 1874, and by 1900 many additional discoveries were made in various parts of the State. Since the most important placer fields of Arizona were brought to light prior to 1875, the most active and prosp~ rous period . for mining them was from 1858 to about 1880. Durmg that pe~' lOd, prospecting in portions of the region was opposed by the IndIans. Before 1885 the cream of the placer gold had been harvested, largely by ~ rude methods of dry- washing, sluicing, rocking, and panning. In order to rework the gravels for . gold not rec? ve. red by early miners, various attempts at dredgmg, hydrauhckmg, and large- scale dry concentration have been made; most, but not all of these afforts have been unsuccessful. In general, the placer industry of Arizona during the last sixty years has been unsteady and has depended upon such factors as unemployment or depressions. EARLY PRODUCTION The total production of Arizona's pl3; cers is difficult to ~ stimate, because the major production was durmg . the early ! rontre~ days, when no records were kept, and many mmers carned theIr gold with them when they left the country. 16 17 The following table is based on conservative estimates which ARIZONA PLACER PRODUCTION, 1902- 50 ( Compiled from U. S. Mineral Resources and U. S. Minerals Yearbooks) for certain districts, may be too low. ' No. of Gold Silver Total ESTIMATED PRODUCTION OF PRINCIPAL ARIZONA GOLD Years mines Fine oz. Value Fine oz. Value value PLACERS PRIOR TO 1900 1902 497 $ 10,273 0 $ 0 $ 10,273 Estimated 1! 103 568 11,741 20 11 11,752 Field Source of 1904 815 16,846 ° 0 16,846 production estimate 1905 2,064 42,663 306 186 42,849 La Paz $ 2,000,000 J. Ross Browne/) 1906 1,959 40,493 274 186 40,679 Gila City 1907 2,172 44,895 365 241 45,136 500,000 J. B. Tenney6 1908 1,497 30,943 258 137 31,080 Laguna 1909 1,386 28,649 183 95 28,744 1910 1,257 25,982 167 90 26,072 Muggins 200,000 1911 42 1,144 23,641 154 82 23,723 1912 51 2,082 43,046 388 239 43,285 1913 36 1,485 30,691 270 163 30,854 Kofa 40,000 E. L. Jones, Jr., 1914 57 1,458 30,140 241 133 30,273 U. S. G. S. Bull. 620 1915 49 1,705 35,248 309 157 35,105 1916 23 691 14,281 171 113 14,394 Castle Dome 100,000 J. B. Tenney6 1917 32 833 17,214 227 187 17,401 1918 13 205 4,234 33 33 4,267 La Cholla 1919 15 227 4,694 36 40 4,734 Middle Camp } 1920 8 221 4,567 15 16 4,583 500,000 1921 37 606 12,524 90 90 12,614 Oro Fino 1922 33 580 11,981 113 113 12,094 Plomosa 1923 24 428 8,854 72 59 8,913 1924 9 152 3,139 27 18 3,157 Weaver } 1925 18 206 4,267 24 17 4,284 Rich Hill 2,000,000 J. B. Tenney6 1926 21 339 7,007 56 35 7,042 1927 15 303 6,257 43 24 6,281 1928 22 310 6,400 46 27 6,427 Lynx Creek W. Lindgren, 1929 22 273 5,652 42 22 5,674 1,000,000 1930 41 632 13,057 85 33 13,090 U. S. G. S. Bull. 782 1931 68 1,069 22,103 157 45 22,148 Hassayampa 1932 179 3,480 71,933 454 128 72,061 ) 1933 179 5,130 131,126 603 211 131,337 Big Bug 1934 867 6,982 244,030 1,038 671 244,701 Groom Creek 1,000,000 J. B. Tenney6 1935 1,197 5,157 180,495 832 598 181,093 Minnehaha 1936 787 6,488 227,066 890 689 227,755 1937 376 4,399 153,965 649 502 154,467 1938 329 4,985 174,475 628 406 174,881 Greaterville 700,000 J. B. Tenney6 1939 142 6,409 224,315 691 468 224,783 1940 276 6.241 218,435 1,108 788 219,223 Quijotoa 250,000 J. B. Tenney6 1941 184 11,931 417,585 2,205 1,568 419,153 1942 163 2,836 99,260 398 283 99,543 1943 19 319 11,165 14 10 11,175 PRODUCTION AFTER 1900 1944 17 242 8,470 90 64 8,534 1945 18 540 18,900 45 32 18,932 As shown in th~ following table, the output reported from Ari- 1946 33 398 13,930 62 50 13,980 1947 30 314 10,990 21 19 11,009 zona place~ s durmg 1902- 50 amounted to 94,560 ounces of gold 1948 39 838 29,330 136 123 29,453 together WIth 14,099 ounces of combined silver valued at $ 2830- 1949 32 565 19,775 63 57 19,832 956. Of this yalue, almost. three- fourths was p; oduced during th~ 1950 24 142 4,970 4,970 ~ en- year perIod, 1933~~ 2, m large part by mechanized operations 1902- 31 27,164 $ 561,482 4,172 $ 2,592 $ 564,074 III the Lynx Creek, BIg Bug, and Quartzsite areas. 1932- 50 67,396 $ 2,260,215 9,927 $ 6,667 $ 2,266,882 . For all of the producing counties except Santa Cruz Pima and 1902- 50 94,560 $ 2,821,697 14,099 $ 9,259 $ 2,830,956 PIllal, the ~) Utput in ounces of placer gold was c~ nside; ably greater durmg 1932- 49 than during 1902- 31. Production figures for 1951- 1959 are given in the Appendix, Page 120. 18 YUMA COUNTY DISTRICTS The noted gold- placer districts of Yuma County include the Gila City, Laguna, Muggins, Castle Dome, Kofa ( S. H.), Tank, Trigo, La Paz, Plomosa ( Plomosa, La Cholla, Middle Camp, Oro Fino), and Harquahala. Their general locations are indicated on Figure 1. Additional small production has been reported from the Fortuna, Sonora, Mohawk, and Ellsworth areas. The Yuma County districts are in one of the most arid portions of the Southwest, with but little water outside of the Colorado and dila rivers. The climate is uncomfortable for placer mining during summer, but very enjoyable in winter. According to the U. S. Weather Bureau, Quartzsite, which is near the Plomosa, La Paz, and Dome Rock placers at an elevation of 800 feet above sea level, has a mean annual rainfall of 6.53 inches, a mean annual temperature of 69.6 degrees, a maximum temperature of 119 degrees, and a minimum of 9 degrees above zero on record. Yuma, which is about 20 miles from the Laguna and Gila City placers at an elevation of 141 feet, has a mean annual rainfall of 3.13 inches, a mean annual temperature of 71.7 degrees, a maximum temperature of 118 degrees, and a minimum of 22 degrees above zero. PRODUCTION The yield from gold placers in Yuma County prior to 1900, as estimated on a previous page, was perhaps $ 3,340, OOq. The recorded output amounted to $ 140,200 for 1905- 31 and $ 341,143 for 1932- 49, or a total of $ 481,143 for 1905- 49. GILA CITY OR DOME PLACERS Situation and accessibility: The Gila City placers, at the northern end of the Gila Mountains, about twenty miles east of Yuma, have been worked over an east- west length of approximately 2 miles and a width of from l/ 4 to % mile. Gila City was about 11h miles west of the present site of Dome, near the mouth of Monitor Gulch. The Southern Pacific Railway and the old Yuma- Gila Bend road skirt the northern margin of this placer ground. History: The Gila City placers became well known in 1858. Hinton, 7 in 1878, recounted their early history as follows: Within three months of their discovery, over a thousand men were at work prospecting the gulches and canyons in this vicinity. The earth was turned inside out. Enterprising men hurried to the spot with barrels of whiskey and billiard tables. Jews came with ready- made clothing and fancy wares; traders crowded in with wagonloads of pork and beans. There was everything in Gila City within a few months but a church and a jail. The diggings continued rich for four years and have been continuously worked on a smaller scale up to the present time. FarishB states that Lieutenant Mowry found, in 1859, about 100 men and several families working the gravels at Gila City and saw more than $ 20 washed from eight shovelfuls of dirt. He was told that from $ 30 to $ 125 per day was recovered by each worker. Although the cream of their production was skimmed before 1865, these placers have been worked more or less e: rery year down to the present time, and all the known productIve gravel areas have been dug over at least once. So far, this gold has been commercially recoverable only by dry washing or by panning of dry- washer concentrates at the river. Many plans have been made for large- scale recovery of the gold, but few of them ever passed the experiment. al stage. One such enterprise, attempted in 1870, has been mentlOned by RaymondU as follows: " At Gila City a San Francisco company has during the last year erected works to pump water fro~ t~ e Gila up into a large reservoir on top of the highest foot- hIlls m order to work the placers of the vicinity by hydraulic power. They use a 9- inch pipe through which they pump the wat~ r." Numerous gold- saving machines, large and small, have been tned out here but most of them were of inadequate design. The remains of one ponderous screw- trommel device, brought here scores of years ago, are still visible. During part of 1931, G. H. Mears attempted small- scale. hydraulicking operations in Monitor Gulch. Water was obtamed from a shallow well near the railway and pumped through about % mile of small pipe. . During the cool portion of the 1932- 33 season, approxImately twenty- five men, mostly transients, were ~ onducti: r: g dry placer operations in the Gila City area. The dally earnmgs per man ranged from a few cents ul? to ~ enerally less ~ han $ 1. The production of the GIla CIty placers prlOr to 1900 h~ s been roughly estimated by J. B. TenneyG at $ 500,000, ~ ost of whICh v.: as made prior to 1865. Their annual output durmg the seventIes amounted to a few thousand dollars. u Their recorded yield for the period 1934- 49 was valued at $ i3,828. Topography: The Fortuna and Laguna topogl'aphic sheets, ~ ssued by the U. S. Geological Survey in 1929, in~ lude the q- Ila City placers. Opposite the northern end of the GIla Mountams, the Gila River bottom lands lie about 165 feet above sea level and are bordered on the south by a gently northward- sloping, dissected bench that rises abruptly from 35 to 300 feet higher. From this bench, which is from 1J4 to 1 mile wide, the main mass of the Gila Mountains rises steeply. Numerous canyon systems, originating in the mountains, have cut steep, northward- trending gulches, from 35 to 150 feet deep, in this b~ nch. . Local geology: Faulted against the schISt of the mam mountain mass is the series of probable Tertiary sedimentary rocks that constitute the bedrock of the bench and of the placer deposits. These beds consist of well- stratified, weakly consoli~ ate~, locally mud- cracked clay, marl, arkose, and sands~ one. The~ r color is pale gray, buff, light green, or red, and theIr textur~ IS generally fine grained, even to the very base of the mountams. This consistently fine- grained character indicates that they were deposited when no high mountains were very near, and the well- 20 developed, locally mud- cracked strata point to deposition in shallow water bodies of considerable size. More or less faulting and tilting are evident throughout this forplation. In the road and railway cuts about 21fz miles north of Blaisdell, the beds strike N. 80 degrees E. and dip 25 degrees SE. The age of the sediments is regarded as probably Tertiary, although they are not as thoroughly cemented as the Tertiary sediments east of Wellton. 3 After tilting, these beds were beveled to a pediment. Overlying this pediment and capping the smooth- topped spurs of the dissected bench is a mantle of gravel, up to 15 feet thick. This mantle extends across the fault that separates the Tertiary (?) sediments from the schist, and continues, as narrowing terraces, for some distance headward into the canyons of the main mountain mass. Most of the material in these gravels appears to represent outwash from the Gila Mountains, but part of it is residual from erosion of the Tertiary (?) beds. Bryana interprets the outwash as having been deposited when the Gila River bed stood about 75 feet above its present level. The age of the gravels is regarded at Quaternary. The gulches that dissect this terrace are floored by gravel, sand and silt that are partly of local origin but mostly have been swept down by flood- waters from the mountains. At the edge of the mountains this material contains subangular to rounded boulders as much as 2 feet in diameter, but, northward, it becomes progressively finer. Gold- bearing groavels: The Quaternary outwashed material constitutes the gold- bearing gravels of the Gila City placers, and the pediment carved on the underlying Tertiary (?) sediments forms their bedrock. Most of the gold was found at or near bedrock in gulches, but a considerable amount was recovered from benches. Practically all the gulches and benches from % mile east to 3 miles west of Dome carry some gold, but Monitor Gulch, 1% miles west of Dome, was the scene of the most active mining. Northward from a point not far south of the railway, the bedrock is reported to extend under the water table. Depths of more than 15 feet to bedrock have not appeared to be profitable for mining. The gold not yet mined from these gravels is distributed in rather spotty fashion. In 1926, Messrs. Neal and Morgan found an $ 88 nugget on one of the benches near Monitor Gulch. They found the gravel to run about 50 cents per cubic yard in a few cuts, but 10 cents or less in many places. The fineness of this gold was about $ 19 per ounce. Ill About half of the nuggets were larger than match heads, and a fourth of them were from $ 3 to $ 6 in value. Almost all of the gold particles were rough, and the $ 88 nugget contained some white quartz. Origin: The gold of the Gila City placers probably came from various gold- bearing quartz veins in the northern end of the Gila Mountains. As no high- grade veins have yet been found there, the negative conclusion that many pockety or smal~ low- grad. e. veins supplied the gold seems most reasonable. Durmg. deposltlOn. of the fine- grained Tertiary (?) sediments, the GIla Mountams probably were marked by low relief, slow erosion, and relatively deep rock decay. After each period of subsequent uplift, they suffered rapid erosion, and the weathered quartz vems of the decayed rocks readily parted with their gold. Floods in th~ young canyon systems swept this detritus northward. droppmg out the gold as the stream gradients lessened. Further milling of these gold- bearing gravels by repeated floods concentrated the gold along the bottom of the channels, on the clayey bedrock. LAGUNA PLACERS The Laguna or San Pablo Mountains, in ranges 21 and 22W., immediately north of the Gila River and the Gila Mountains, contain gold placers' in their southern, southeastern, and southwestern portions. The Laguna quadrangle sheet, issued by the U. S. Geological Survey in 1929, shows the local topography. . Production: The total output from the Laguna placers IS unknown. Their recorded production during 1930- 42 was valued at $ 20,103. McPhaul area: Considerable placer mining has been done along the southern margin of the Laguna Mountains, fr~ m near the Gila River to about 1% miles north of McPhaul Bridge. A little dry- washing is still carried on. Only scanty production records for this particular area are available. During some years, its yield was lumped with that of Gila City. These placers, which conform to the exposure of tilted, beveled, Tertiary (?) sediments that constitute their bedrock, occupy an area of approximately % square mile, limited on the north and east by the hard rocks of the Laguna Mountains, on the south by the Gila River bottom lands, and on the west by the high gravel capping of the range. The Tertiary (~) strata, wh? se gener~ l character has been described on a prevlOus page, strIke and dIp in various directions and have been displaced by reverse faults of northeasterly trend. Many southeastward- trending arroyos have dissected the area. Most evidences of placer mining activity are confined to inter- arroyo benches near the base of the overlying gravels, but some at lower elevations and also along arroyo bottoms are evident. Las Flores area: Las Flores district, in the southeastern portion of the Laguna Mountains and 11/ 4 miles north of the Gila River is near the head of an alluvium floored gulch, at an elevation of 300 to 400 feet above sea level. The erosion of several goldbearing quartz veins in this district has given rise to small placer deposits. . . .. According to Raymond, 9 placer mmmg was carned on m Las Flores area chiefly by Mexicans and Indians, at about the time when the Gila City placers were most active. Part of this placer 22 gold occurred in the vicinity of the Golden Queen and India claims, and some was followed downstream to the bank of the Gila River, A little placer mining has been done in several gulches along the southern margin of the mountains. No record or estimate of the amount of gold recovered is available. Laguna Dam area: At the eastern end of Laguna Dam, about ten miles northeast of Yuma, masses of black schist and coarse, granitic gneiss rise steeply for 250 feet above the Colorado River. Erosion of quartz veins in these rocks has given rise to coarse, rusty placer gold that, in places, extends into the bed of the Colorado River. In 1884 or 1885, an attempt was made to recover this river- channel gold by dredging, but a flood destroyed the dredge. In 1907, during the construction of Laguna Dam, placer nuggets and a small gold- quartz vein were found at the river margin of these mountains. Considerable prospecting has been done in several of the gulches of this area, and potholes, up to 100 feet above the river, were found to carry rather coarse gold. This coarseness points to a local origin rather than to long transportation by the Colorado River. The U. S. Mineral Resources report from the Laguna placers a production of $ 1,457 in 1910 and $ 1,989 in 1912. The potholes yielded most of this amount and have made some production since then. Similar, but most extensive, pothole placers occur on the California side of the Colorado River. During the cool portion of the 1932- 33 season, a maximum of fifty men were conducting dry- placer operations in the McPhaul and Las Flores areas. All of the ground was privately owned, but, in general, no royalties were charged. The average daily earnings per man were between 50 and 75 cents. At the same time, approximately twenty- five men were placering in the Laguna Dam area. MUGGINS PLACERS The Muggins Mountains, which occupy parts of Twps. 7 and 8 S" R. 18, 19, and 20 W" contain gold placers in their southern and central portions. These placers have been known for many years b~ t, be, cause of being less easily accessible than the neighboring GIla CIty area, they have not been so intensively worked. The Wellton, Fortuna, and Laguna quadrangle sheets, issued by the U, S, Geological Survey in 1929, show the topography of part of the Muggins Range. In the southern portion of the range, the major placers occur in Burro Canyon. Minor ones are found in smaller canyons in the vicinity of a prominent mountain that is variously known as Klotho, Coronation, or Muggins Peak, and also at the southern base of Long Mountain. Burro Canyon, which is accesible from Dome by some 10 miles of unimproved road, trends southward from Muggins Peak. Here, southward- dipping lava flows, intercalated with thick beds of conglomerate, form a rugged terrain, This conglomerate, which consists mainly of coarse, subangular pebbles of gneiss and granite, rather firmly cemented in a sandy to clayey matrix, forms the bedrock of the placers. The goldbearing gravels occur principally as ancient bars several feet above the stream channel and, to a less extent, i~ the. pre, sent stream bed, The gold occurs as particles up to 0.15 mch m dIameter, mostly concentrated at or near bedrock. It. appea. rs t~ have been derived by erosion of the conglomerate, m whIch It was probably present as low- grade placer material deriv: ed frOi? goldbearing quartz veins originally contained in the gneISS, schIst, and granite of the range. , ' Gold placers occur in the central portIOn of the Muggms Mountains in the vicinity of the headward forks of the long, northwest~ ard- trending canyon that bisects the ra~ ge. The grav. els of this canyon, which are reported to hav: e yIelded many nch pockets during the early days, are occaSIOnally worked ~ f~ er heavy rains. This gold probab~ y ac: umulated. from the, dIsmtegration of quartz veins contamed m the adJacent schIst and gneiss. ' f During the cool portion of the 1932- 33 se~ son,. a maXImum 0 approximately twenty- five n~ en were workmg m the southern Muggins placer area. The dally recovery per man was generally less than $ 1. Practically all the water used must be hauled from wells in the Gila Valley. During 1932, E. H. Rhodes, storekeeper at Dome, purchased $ 2,296 worth of gO, ld w~ ich came Pl~ rtly f: om the Muggins and partly from the GIla CIty placers. BeSIdes this amount an unknown quantity from these areas was marketed elsewher~. The recorded production during 1934- 42 was valued at $ 6,867. CASTLE DOME PLACERS The principal gold placers of the Castle Dome M~ untains are east and south of the Big Eye mine, which is 31 mIles by ro~ d northeast of Dome. The gold occurs mostly at or near bedrock m gulches and appears to have been derived from erosion of gold-bearing veins in the vicinity. .' These placers were discovered in 1884" but theIr productIOn to the end of 1907 is unknown. The U. S. Mmt report for 1~ 87 states that the field was being worked in a crude way by MeXIcan drywashers. According to data and esti~ ates compiled by J. B. Tenney, 6 their yield for the 1884- 99 penod would amount to between $ 75,000 and $ 100,000. During 1932- 33, seldom more than two or three men w~ re working in this placer field. Operations are hampered by scarCIty of water. . The recorded value of output was $ 10,247 for 1908- 25, and $ 29,589 for 1934- 44. KoF'A OR S. H. PLACERS A small area of gold placers in the Kofa or S. H. Mountains of central Yuma County, about 56 miles northeast of Yum. a,. ~ as been described by Jones. ll A geologic sketch map of the VIcIDlty 24 Figure 3.- Preliminary geologic reconnaissance map of the Kofa or S. H. placer area, after E. L. Jones, Jr., and N. H. Darton. is shown in Figure 3. Of these placers Jones says: The known placer deposits of the Kofa Mountains occur in a gulch draining westward north of the detached hills in which the King of Arizona mine is located. These placers have been worked for many years, and the production is reported to be about $ 40,000 in gold nuggets. At present ( 1914) the placers are being worked in a small way, and a yearly production of several hundred dollars is reported. The gold occurs in outwash deposits which consist of boulders and fragments from the metamorphic and volcanic rocks. The gold- bearing debris is said to be from a few feet to seventy feet deep over an area of approximately sixty acres. The gold is coarse and occurs near bedrock. It has evidently been derived from the disintegration of auriferous veins in the metamorphic rocks, as it is much coarser than that contained in the North Star and King of Arizona veins. ll During the winter and spring of 1932- 33, eight to ten men were working in the Kofa placer area. The average daily recovery per man. was 75 cents or less. Production of gold during 1935- 48, as credIted to the Kofa placers by the U. S. Minerals Yearbooks, was valued at $ 1,650. TANK MOUNTAINS PLACERS Some placer gold has been mined in the Tank Mountains at various times since the seventies, but no record of the production is available. Probably the earliest and most profitable activity was in the main gulch below the Johnnie or Engresser prospect, in the northwestern portion of the range. This placer gold presumably was derived from local gold- bearing veins. As the field was small its richer ground was soon worked out, but during the past sev~ ral years it occasionally produced a small amount of gold. Some fifty years ago, active dry- washing was carried on in shallow bench and stream gravels on the pediment near the Puzzles, Golden Harp, Ramey, and Regal prospects, at the eastern f{ lot of the range. The gold obtained from the Puzzles area is said to have been coarser than that from the other localities. 0,-,- l'-- L'... J'- J..__~~ Mile 5 ",,- KEY .............. 1 IOulwash fITTTTTJ rI1f I i ary lu. ll.. 1lJ andesile l7777:: l M( 110marphic tLLLLJ rock ~ Go/~- bearing L----. J v tI inS Recent production from these areas has been practically negligible. TRIGO PLACERS The Trigo placers are at the western' base of the Dome Rock Mountains, in T. 2 N., R, 21 W., approximately 22 miles by road from Quartzsite. The gold- bearing gravels occur in arroyo bottoms and in ancient bars and channels. Most of the gold is in the form of flat grains. For many years, small- scale, intermittent dry- washing operations have been carried on in this field, but no record of the total production exists. Operations are greatly hampered by the scarcity of water and the cemented character of the gravels. Their output during 1936- 49 was valued at $ 3.700. LA PAZ PLACERS Situation and accessibility: La Paz placers are south of the Colorado River Indian Reservation of west- central Yuma County, along the western foot of the Dome Rock Mountains, abOl~ t 9 miles west of Quartzsite and 6 miles east of the Colorado RIVer ( Figure 4). The district is accessible by some 5 miles. of unimproved road that branches northward from the QuartzsIte- Blythe highway. Topography: The Dome Rock Mountains rise steeply to , approximately 2,900 feet above sea level or more than 2,000 feet above the adjacent plains and are extensively dissected by deep canyons. From their western foot, a wide dissected bench slopes gently westward to low bluffs that limit the Colorado River bottom lands. No perennial streams flow through the placer district, but branching arroyos drain the run- off of rain:\:, seasons to the Colorado River. Water is hauled from QuartzSIte or from shallow wells near the river. A scanty supply is afforded by Gonzales Wells or by natural rock tanks, such as Goodman Tank. History: According to former State Historian Hall, l° the presence of placer gold near the Colorado River was learned from Indians soon after establishment of the military post at Yuma. These Indians gave a few small nuggets of gold to a trapper, Capt. Pauline Weaver, and about 1862, according to Browne, 5 guided Weaver and his party to the rich gravels. The party picked up about $ 8,000 in nuggets, returned to Yuma for supplies, and spread news of the discovery. Several hundred miners soon rushed to the district, found the placers to be very rich, and established the adobe town of La Paz about 2% miles from the river. This town, which soon attained a cosmopolitan population of over 1,500, became a station on the Overland ' I'rail from San Bernardino to Ft. Whipple and was the County seat until 1871,12 The district flourished until about 1864 when apparent exhaustion of the higher- grade placers and discoveries of new diggings caused a decline in activity. In 1873, 1874, and 1876, additions to the Colorado River Indian Reservation included much of the placer ground and greatly restricted mining. La Paz be- 27 26 o ,.. D. )- I '"'" [ J~ [ 3= a z ' w" ++ • a g I- ~ m :':"> " , 0 c a Vl t 0: ) )-'" "" z'' l' '-' ",'" ~~ ~ a oz q fa « ~~ o z?;:~ q'" c(~~ ~:..~ ~ 5 " c . J I-a. X w~ q I'" W I-came practically deserted, and the site of this once flourishing town is now marked only by adobe ruins. After the area was excluded from the Indian Reservation in 1910. New La Paz Gold Mining Company acquired control of a large portion of the placer ground and made preparations for large- scale hydraulic treatment of the gravels. Four shallow wells were drilled in the Colorado River flood plain some 4% miles west of the placers. Water was to be pumped from these wells through a 12- inch pipe line to a reservoir 540 feet above the river or 225 feet above the placers. Part of the pipe line was installed, but from 1912 to 1915 the land was again included in the Reservation, and the project was not completed. Several other plans for large- scale operations have been outlined, but none of them have been carried out. Production: Information on the earlier production of the La Paz placers is given by Browne,'; who quotes a letter from A. McKay, a member of the Territorial Legislature from La Paz, as follows: Of the yield of these placers, anything like an approximation to the average daily amount of what was takeJ; l out per man would only be guess work. Hundreds of dollars per day to the man was common, and now and again a thousand or more a day. Don Juan Ferra took one nugget from his claim that weighed forty- seven ounces and six dollars. Another party found a chispa weighing twenty- seven ounces. Many others found pieces of from one to two ounces up to twenty, and yet it is contended that the greater proportion of the larger nuggets were never shown.... It is the opinion of those most conversant with the first working of these placers that much of the greater proportion of the gold taken out was in nuggets weighing from one dollar up to the size mentioned above..... As has been said above, the gold was large and generally clear of foreign substances. .... All that was sold or taken here went for $ 16 to $ 17 an ounce. Since the year 1864 until the present, there have been at various times many men at work in these placers, numbering in the winter months hundreds, but in the summer months not exceeding 75 to 100; all seem to do sufficiently well not to be willing to worl< for the wages of the country, which are and have been for some time $ 30 to $ 65 per month and maintenance. No inconsiderable amount comes in from these placers now weekly, and only a few days ago 1 saw, myself, a nugget which weighed $ 40, clear and pure from foreign substance. . . . . Of the total amount of gold taken from these mines, 1 am at a loss to say what it has been.... 1 have failed to find any pioneer whose opinion is that less than $ 1,000,000 were taken from these diggings within the first year, and in all probability as much was taken out in following years. According to Hall, IO local gold nuggets and dust were the principal currency, particularly for gambling, in La Paz; but a large portion of the gold obtained by Mexican placer miners went to Mexico. On account of the crude methods of recovering the gold, entirely by dry washing in pans or wooden " bateas," only the coarser gold could be saved, and only extremely rich ground would be payable. Wet methods were out of the question, for, according to Jones, 14 water packed from La Paz to the placers brought $ 5 a gallon during the rush period. With the introduction of dry- washer machines in the late sixties, greater quantities of material could be handled and a greater percentage of 28 recovery effected, but by that time most of the richer ground had been worked over. During the winter of 1932- 33, from fifty to sixty men were reported to be conducting small- scale, individual dry- washing operations in La Paz district. The average daily recovery per man was from 50 to 75 cents. La Paz placers are credited with a gold output valued at $ 14,705 for 1934- 37 and $ 805 for 1942- 49. Their production for other recent years is not separately recorded. Local geology: The Dome Rock Mountains in this vicinity ( Figure 4) consist largely of metamorphic rocks and granite, of Mesozoic to early Tertiary age. For a short distance west of the foot of the range, these rocks floor a dissected pediment and constitute the bedrock of the principal placers. Westward they disappear beneath extensive deposits of sand, gravel, and clay which in turn are locally overlain by coarse outwash grav~ ls and boulders. Distrib~ tion. and character of the placer gravels: The placers oC, cur mamly m Goodman Arroyo a~ d Arroyo La Paz, and in trIbutary gulches such as Ferrar, GarcIa, and Ravenna. According to Jones, 13 Ferrar Gulch, tributary to Arroyo La Paz, contained the richest and most productive placers of the district. Evidences of former work are seen in the old excavations and, ... in exposures of bedrock where the wash was shallow.... The thickness of . the gold- bearing wash is variable, ranging from a few fe~ t on the mountam slopes to an unknown measure in Arroyo La Paz and m the gulch traversed by the ( old) Quartzsite- Ehrenberg road.. Shafts have bee~ ~ unk in the wash to depths of thirty feet without reachmg bedrock and It IS reported that in places the wash is at least sixty feet deep. By far the greater part of the auriferous material is unworked especially that in the lower courses of the arroyos where the wash i; deep, F'errar Gu~ ch for mo, st of its course has been p; actically worked out. The gold- bearIng materIal consists of sand and clay inclosing angular rock fragments of greatl~ variable size. Tests indicate that about twenty per cent of the wa~ h wIll pass through a quarter- inch screen, and tli'e largest ~ oulders weIgh several hundred pounds. The material near the s1! rface IS unassorted and is unconsolidated, being readily worked with pIck and shovel.. That at depths of fifteen or twenty feet is consolidated but t~ e cementmg substances readily disintegrate on exposure to air: DepOSIts of wash below the depths of test pits may prove to be similar to the outwash on the east slope of the Dome Rock Mountains and in the Plomosa placers, where the material is firmly cemented with calcium carbona~ e and requires crus1; lin~ in. order to free the gold. The ground stands suffiCIently well to permIt smkmg of shafts without use of timber The w~ sh is readily worked in dry- washer machines, the only requir~ ment bemg that the ground must be dry. The gold is said to be distributed throughout the wash, though in the early workings the richest yield was obtained near bedrock. No estimate could be made of the probable gold content of the wasli in the La Pa~ ~ istrict because of la~ k of detailed data and of uncertainty as to the lImIts of the wash, but In one area the deposit, said to contain values of 50 to 75 cents per yard and much of it thirty feet or more deep occupies at least 640 acres, and considerable areas extend into the small': er gulches. The size of the gold now recovered from the deposits of the La Paz. district probably averages only a few cents, but as' already stated the gord recovered from the early workings was much coarser. The gold' is rough ~ nd angular, an~ particles of iron cling to some of the nuggets. Magnetite IS ~ lw~ ys found In the concentrates, and boulders of magnetite, the largest welgh. Ing several pounds, are frequently found on the surface. HeIkes14 states that the largest nugget found in this region was valued at $ 1,150 and assayed about 870 in fineness. Most of the gold particles or nuggets ranged in value from 5 cents to $ 10, although $ 20 and $ 40 nuggets were not uncommon. La Paz placers were probably derived by the erosion of many gold- bearing veins in the Dome Rock Mountains. PLOMOSA DISTRICT The Plomosa placer district includes the eastern and western margins of La Posa Plain. This plain, which separates the Plomosa Mountains on the east from the Dome Rock Mountains on the west, is approximately ten miles wide and from 1,000 to 1,300 feet in elevation. It is dissected, particularly in the marginal portions, by many shallow arroyos tributary to its northwardflowing axial channel, Tyson Wash. These arroyos contain no water except for short periods after heavy rains. Most of the water used in the western part of the district is hauled from shallow wells at Quartzsite. Heikes14 states: " Surrounding the post office of Quartzsite, in the Plomosa mining district, and extending in every direction, covering an area of about 7,500 acres, is found dry- placer ground with values to an average depth of fifteen feet and varying from five to fifty feet. The gold content per cubic yard is reported to average in coarse gold from ten cents to several dollars." The most important placer fields in the Plomosa district are La Cholla, Oro Fino, and Middle Camp, which lie near the Dome Rock Mountains, and the Plomosa, near the Plomosa Mountains ( Figure 4). These areas have been worked intermittently by individual dry- washers since the early sixties. Several lP. rge- scale operations have been planned or attempted. The 1901- 31 value of production from the Plomosa placer district is given by the U. S. Mineral Resources as $ 44,826. During part of the winter of 1932- 33 more than 100 men were reported to be placer mining in this district. The recorded yield during 1934- 49 was valued at $ 176,042. LA CHOLLA PLACER AREA La Cholla placers comprise an area 4 or 5 miles long and of irregular width bordering the eastern foot of the Dome Rock Mountains south of the Quartzsite- Blythe Highway. Here, a gently eastward- sloping pediment or rock floor eroded largely on tilted bluish- gray slates, borders the mountains and extending beneath the gravels of the plain, constitutes the bed~ rock of the placers. The gravels in general consist of an unassorted aggregate of subangular to slightly rounded slate, schist, and quartzite fragments, more or less firmly cemented with lime carbonate. They I 30 are commonly of medium texture but range in size from fine material to boulders 3 or 4 feet in diameter. The gold occurs mostly at or near bedrock, but some is erratically distributed throughout the gravels. Its particles are characteristically angular and crystallized and range in diameter from that of a pin point up to liB inch or more. The gold has not been transported far and probably was derived from numerous small gold- bearing veins in the adjacent mountains. BInd: sand is abundant only in the shallower diggings. During the first half of 1933, the principal activity in La Cholla placers was on a group of three claims held by G. W. McMillen and Guy Hendrix. On part of this ground, at the eastern foot of a low, steep spur, many old pits, shallow shafts, and drifts proclaim earlier placer mining actiVity. A few hundred feet farther east, the operators sank a shaft tha, t struck bedrock at a depth of 84 feet, According to Mr. McMillen, lO a small pay streak was cut at a depth of 42 feet, and rather finely divided gold was found 15 feet above bedrock. At bedrock, the shaft encountered a rich southeastward- trending channel. When visited in June, 1933, this channel had been followed by some 300 feet of drifts and minor stopes, but its width and length had not been determined. As shown by these workings, the bedrock surface slopes about 15 degrees southeastward and forms natural riffles. The richest gold- bearing gravel occurs within a few inches of the bedrock and is particularly concentrated in the Vicinity of reefs and undulations on the bedrock surface, or where boulders are abundant. In places, it contains up to an ounce or more of gold per cubic yard. Locally, crevices in the bedrock contain placer gold for depths of 1% to 2 feet. Although openings in these cemented gravels required little or no timber, the material mined did not require crushing, It was run through a %- inch trommel screen and then conveyed to a bin from which it was passed over a two- tier dry- washer driven by a small gasoline engine. The tailings from this operation contained approximately 50 cents in golq per cubic yard. Production during the first half of 1933 amounted to about $ 6,000 in gold that ranged from 920 to 924 fine. Five men were employed. In June, 1933, the gravels in a secondary surface channel, a few hundred feet north of the shaft, were being mined with a power shovel. These gravels, reported to run 75 cents per cubic yard, were being treated experimentally in a wet jig for which water was hauled from a well 3% miles distant. Production figures for La Cholla placers are not available. According to the U. S. Minerals Yearbooks, La Posa Development Company during 1939 operated continuously in the area and handled 15,033 cubic yards of gravel; this project was suspended in early 1941. ORO FINO PLACER AREA The Oro Fino placers are at the eastern foot of the Dome Rock Mountains, in the Vicinity of the Quartzsite- Blythe highway. 31 Here, tiltEd,. beveled shl atI. e alndt~~ te n~~~ s~~~ t~~:~ fa~~~ c:~ n'ER~ gravels, WhlCh ar~ re a lVe y m much slaty materIals. t' I mined but During the early days, the~ e placer11 : e: e ~~ ~~~ h, iduals,' Ac- ~~ r~~~~ e~~ ~~~~~~[ J~ g ~~;~ s I~ it~~~ fr~~~ l~~ r~ ps~~~ l~~~~ ~:~~~ ! ina Gold Mmmg ~ m~ a~ y t W From these samples it was found sunk every few hun re ee. f ents to ' over $ 1 per that the gold content ranged from a :~ cThe colors ran from cubic yard and aver~ ged ~ 8 cen~ s ~~~ ~ he gold was of about $ 19 less than 1 cent to 2 cen s, eac, $ 20 67 er ounce). Here the per ounc~ fineness, ( laluat~ of~ a~ f u~ con; olidated rock debris, ~~ l~:~~ r:~! t ili~~~~ I: ndc~~~~ rlYingcemented gravel 18 or more feet thick. MIDDLE CAMP PLACER AREA The Middle Ca~ p placer area, I, U:~ Oed~' etsetlybynoarthmiolef twhiedeOraot Fino, is 4 or 5 mIles long from ea~ Mountains Here according theCehastehrn14fo" oRticohf tsheeamDsom0 fegRraovcel on bedrock yield' f. romthfour ttoo tenurtI~ m, es the vaIue 0 f th'ICker 1g0ratve$ ls25a" nd in creVIces ere halvl- eurbinegen1f9o3u2, ndtwnougcgoemtspawm? erstha$ ttempOted iarge- scale operations in this tract. d f M'ddle Camp Placer Gold, Inc., La On ground lease rom I. ed ut a large machine equipped Cholla Mining Compal ! 1y, L~ d., yl p; roximately 100 feet of sluice with a 3lh- yard drag me s ove, a r cover This machine, for boxes, and settlinghtanlksd which wa: er was au e ff~~: aQte~ ar~ zsite, y; perated for only a few we~ ks. I C r oration installed a plant equipped Amencan ~ oarhse G1d d ~ Po Cottrell tables. It was operated, with a draglme s ave an w . f b t two weeks. with water hauled from, Qu~\ t; s~~~ n~;~ n~~ viduals were carryingInonJusnme, all1- 9s3c3a, leapdprryo- xwlmasha. meg m. the Middle Camp placers. PLOMOSA PLACER AREA d f La Posa Plain and the western Placers at the eas~ rn ~ ~ e 0 bout 5 miles southeast of Quartz-foot of the Plomosa oun aIns,. a bl old in the early sixties, site ( Figure 4), pro~~ c:~ oc~~: I~ er: va~ atle. Bancroft, lG in 19~ 9, but no record ? f t f h nd had been honeycombed WIth found that portIOns 0 t e grou b made to work these small tunnels. Various attempts h~ vean~ e~ et methods. Considplacers on a la. rge scalbe, both bi t y erable productIOn has een ma e yindividual, small- scale dry-washing. t ' h' h east of the district are about The Plomosa Moun ams, w IC b e the plain consist 2la0r0g0elfyeeot faSbCoh~ Iest, segaralmeyteel, aonr dl~~~ e; e~~ l~ a~~ rocIes. Th~ schist, 32 which contains gold- bearing quartz veins and stringers, was probably. the original source of the placer gold. Accordmg to Bancroft, the placer gravels, which occur in old drainage ch. annels leading away from the southwestern part of the mountams, are made up of fragments of schist, granite, and quartz, cemented by lime carbonate. This conglomerate or " cement rock" ~ anges in thickness from a few inches up to many feet, dependmg largely on the shape and size of the former channels, arid rests upon grayish- green, schistose bedrock. Regarding the placers, HeikesJ. i quotes extracts from a professional report by John A. Church as follows: In some localities pits have been sunk to a depth of twenty thirty and fifty feet or. more to be9s of cement which are richer than the gravel. Near the mounta~ n the gol~ IS coarser, but the gravel is much less. Miles of the great depOSit, extendmg westward from the mountains and from three to fo~ r miles in width, have been cut into by deep ravines, and they afford ~ I1es of banks ten to fifteen feet high in which the upper layer of gravel IS well exposed. From these banks, as far as investigations could be made, saIJ; lples gave an average return value of 64 cents per cubic yard with gold estunated at $ 18 an ounce.... There were no failures. The results lay between the extremes of 42 cents and $ 1.04 per cubic yard. The limit of the gr~ v~ l act. ually explored was 2,400 by 1,500 feet and eight yards deep.... Wlthm thIS area bedrock was not reached at any time. During. the winter of 1932- 33, approximately twelve men were engaged m small- scale dry- washing operations on the Plomosa placers. Average daily earnings per man were from 25 to 50 cents. Production dUring 1942- 49 Was reported to be valued at $ 5,740. HARQUAHALA PLACERS The late L. C. Shattuck, of Bisbee, stated lO that, in 1886 and 1887, he worked a small placer in Harquahala Gulch which is in the southwestern portion of the Harquahala Mount~ ins 8 miles south of Salome. For a short while, Mr. Shattuck and hi~ partner e~ ch recovered abou~ an ounc. e of ~ old per day. Although long ~ mce w? rked (: mt, t~ I~ ~ lacer IS of mterest because of occurring m the Il? medlate VICI! 1Ity of the rich Harquahala or Bonanza lode, whIch was not dIscovered until 1888. MOHAVE COUNTY DISTRICTS AND PRODUCTION In Mohave County, gold placers have been worked in the Chemehuevis, Silver Creek, Lewis, Lookout, Wright Creek Willow Beach, Gold Basin, and King ' Tut ( Lost Basin) areas. The most productive of these have been the King Tut Gold Basin and Chemehuevis. " The recorded yield from gold placers in the County was valued at $ 3,442 for 1909- 31; $ 52,446 for 1932- 49; and a total of $ 55,888 for 1909- 49. CHEMEHUEVIS PLACERS The Chemehuevis placers of southwestern Mohave County are in the foothills of the Chemehuevis or Mohave Mountains, about 18 miles southeast of Topock. This area is part of the Gold Wing mining district. Its climate is relatively dry throughout the year and hot during summer. In general, the gravels are angular and free from large boulders. Where deep, they are cemented with lime carbonate. The gold is fairly coarse. During the winter of 1932- 33, a maximum of thirty men were working at one time in the placers of the Chemehuevis Mountains, but most of them left with the advent of hot weather. According to the late J. H. Jones, lO formerly of Topock, their gold production amounted to about $ 1,200. A little activity was reported in Dutch and Printer's gulches, on the northeastern side of the range. The Chemehuevis placers have been worked intermittently by small- scale dry methods fot many years. Probably the most activity has been in the Mexican or Spanish diggings, in the vicinity of the Red Hills, at the southwestern foot of the range. The recorded production of placer gold from the district during 1934- 43 was valued at $ 7,111; it came largely from the Chief claim. SILVER CREEK PLACERS Some minor gold placers occur in the valley of Silver Creek, about 6 miles by road downstream from U. S. Highway 66 and 5 miles northwest of Oatman. lIere, an irregular pediment of volcanic rocks is overlain by a mantle of gravels which locally contain a little placer gold. During the winter of 1932- 33, Gold Gulch Gravel Company attempted to work this ground with a large centrifugal bowl machine for which water waS piped several miles. A short run, however, sufficed to determine that the gold present was insufficient to make the project profitable. A short distance farther southeast, a little small- scale placer mining, chiefly sluicing in connection with assessment work, has been carried on. According to B. White, lO one of the operators, the gravels there are very firmly cemented with caliche and contain about 100 pounds of black sand per cubic yard. This gold is about 730 in fineness. LEWIS PLACER The Lewis placer is on patented property of the old Bi- Metal gold mine, 3 miles southwest of Kingman and % mile northeast of McConnico. Here, a granite area about 300 feet in diame. ter has been considerably mineralized with slightly auriferous pyrite. Regarding the Bi- Metal deposit, Schrader10 says: The free gold to which the deposits owe their value seems to have been derived from a considerable thickness of overlying mineralized rock. As this overlying rock became disintegrated and was removed by erosion, the fine gold liberated from it gradually worked into the underlying rocks in which it is now found. Below or outside of the oxidized zone of mechanical concentration probably only very low- grade ore occurs. In 34 ~~~:~~;~~ e~ l~~~~~~ t: ti of dr b ainftage j within or at the border of the area, t bi on y ow ng water has taken place several ~ n~ i~: n~~ u~ f:~ rly ~ o: re gold, of which some of the largest nuggets been panned. a a 0 ar each in gold value, are reported to have During the winter of 1932- 33, Al Lewis mined and sluiced the gravels from 17 a sma~ l draw in. this area. According to E. Ross Householder, of Kmgman, thIS material ranged in value from $ 1 to $ 5 per cubic yard and yielded about $ 900 in gold that was worth $ 20.21 per ounce. LOOKOUT PLACERS The Lookout placers are in the Maynard mining district near the northern ~ nd of the Hualapai Mountains, about 6' miles ~~ iit~ deast of Kmgman. Here, certain areas of shallow gulch and 1 SI ~ 7gravels contain rough, wiry placer gold. E. Ross House- $ holder states that one dry- washer in this area obtained about 150 worth of gold during the 1932- 33 season. WRIGHT CREEK PLACERS Sm~ ll gold plac~ rs occur in the upper reaches and tributaries C1. jirl1: ht Cre~ k, In the northeastern portion of the Cottonwood I s. ntermIttent, small- scale operations have been carried on here for the past decade, but the total production has been small. COLORADO RIVER PLACERS thThe sands and gravels of the Colorado River, downstream from e. mouth of the qrand Canyon, contain finely divided gold whIch several dredgmg and sluicing operations have attempted to ? flover: .? ne of these enterpr~ ses is mentioned by Heikes18 as 0 thWA . The l~ rge dredge bUIlt in 1909 on Colorado River near e ~ Izona sIde, opposite EI Dorado Canyon Nevada wa~ of. the suctIOn type .... It was built to work the ~ and bar~ and faIle. d on firs~ test to extract the fine gold. It was subse uentl car: Ied from ItS moorings by high water and wrecked duJrig th~ sprmg of 1910." River- bar placers: Minor amounts of coarse gold have been ~ ecovefred by small- scale operations in elevated bars that have een or? 1ed largely by tributary canyons. At WIllow B. each, 65 miles from Kingman and near the Hoover Da~ hIghway, one of these ancient bars contains the ~ andY HarrIs placer. This bar covers an area of about 250 square eet, near the . outer bow of a curve in the Colorado River and rbsts upon an Irregula~ surface of gneissic granite some 150 feet bo~ rd the strealm. 1 d t IS made up of an unassorted aggregate of ers, gr~ ve , an. sand. The boulders, which range u to mo~~ than SIX feet m diameter, are but slightly rounded Pand cou not h; av~ been transported far. Likewise the coar of the gold mdIcates a local derivation. This pla~ er materi: i:~ pro~ a~ yb eroded fro~ gold- bearing rocks in the Vicinity and was e, y way of trIbutary gulches, to the river where it ac-cumulated in the outer portion of the nearest c » rve. Subsequent downcutting of the river has left this bar elevated in its present position. Some thirty- five years ago, Mr. Harris worked this placer by tunneling on bedrock. In 1920, an unsuccessful attempt was made to sluice the gravels with water pumped from the river. A lessee took out about ten ounces of gold during 1931. Black sand is abundant in this placer. Some medium coarse placer gol< l has been recovered from a bench near the Colorado River about 21h miles north of Pyramid Rock. GOLD BASIN PLACERS Situation: The Gold Basin Placers of northwestern Mohave County are in T. 28 and 29 N., R. 17 and 18 W., about 9 miles south of the Colorado River. Their central portion is accessible by about 9 miles of unimproved road that branches northward from the Kingman- Chloride- Pierce Ferry highway at the northern end of Red Lake playa, 56 miles from Kingman. History: The first known discovery of placer gold within this area was made in May, 1932, by W. E. Dunlop. In August of that year, approximately 100 men were testing the field with dry- washers. Most of them left during the winter rainy season, but about forty were there in June, 1933. As most of these people were transients who took part of their gold elsewhere, any approximate estimate of the production is difficult to reach. Experienced, industrious workers each made $ 1 or more per day, but most of the operators averaged less than that amount. Drywashing here is interrupted during rainy seasons. During the summer of 1933, a large- scale dry- treatment plant ( Plate I) was installed by S. C. Searles in Sec. 29, T. 29 N., R. 18 W. This plant, equipped with grizzley, trommel, screens, and a battery of twelve dry- washers, had a rated capacity of 20 cubic yards of gravel per hour. The U. S. Minerals Yearbooks credit the Gold Basin placers during 1934- 49 with a gold production valued at $ 14,500. Topography and geology: Gold Basin is floored largely by a detrital fan that slopes eastward from the White Hills to Hualapai Wash. This fan is approximately 6 miles long from west to east by 5 miles in maximum width. Its vegetation consists principally of small desert shrubs and abundant Yucca or Joshua trees. Water for all purposes is hauled chiefly from Patterson Well, several miles away. The gold- bearing gravels occur principally in arroyos and gulches, between elevations of 3,300 and 2,900 feet above sea level. They consist mainly of medium- grained, angular schist and gneiss fragments together with a minor amount of finely divided quartz. A small proportion of boulders, generally less than 2 feet in diameter, is present. The placer gravels are mostly from 1 to 3 feet thick and rest upon a bedrock of firmly cemented gravels. Their gold occurs partly as flour gold and partly as angular fragments that range from 5 cents to $ 3.50 in 36 37 value. Some of the gold is attached to black schist particles. Black sand is rather abundant. The tests that have been made of this ground show that the gold is erratically distributed. Certain pockety channels contain thin streaks that run more than $ 1 per cubic yard, but most of the arroyo banks probably contain less than $ 1 per cubic yard. The cemented gravels of the bedrock are reported to carry a little gold, but no test of them has been made. Origin: The White Hills, which are made up of granitic, schistose, and volcanic rocks, contain many argentiferous and auriferous quartz veins. 16 Erosion of such veins doubtless gave rise to the Gold Basin placers. The occurrence of most of the gold as angular fragments, some of which are attached to black schist particles, indicates some such nearby source. KING TUT PLACERS Situation: The King Tut placers of northwestern Mohave County are in T. 29 and 30 N., R. 17 W., about 8 miles from the Colorado River. They are accessible from Kingman, via Chloride and the Pierce Ferry Highway, by 72 miles of improved road. History: So far as is known, the first discovery of placer gold within this area was made in February, 1931, by W. E. Dunlop. According to Charles Duncan, l° the gold production prior to June, 1933, was incidental to sampling and amounted to about $ 700. All of this land was privately owned, chiefly by the Duncan ranch and by the Santa Fe Railway. On the Robeson and Joy lease, in sec. 14, T. 30 N., R. 17 E., a Cottrell dry concentrator with a capacity of 25 tons of gravel per hour was being installed. During 1934- 42, a gold production valued at $ 23,510 was credited to the Lost Basin ( King Tut) placer area. Topography and geology: Here, a gravel- floored plain, from 3,000 to 4,000 feet above sea level, rises southwestward between Grapevine Wash and the base of a low northward- trending ridge locally called the Lost Basin Range. Near these mountains, the plain is a pediment floored with schist and granite. Its vegetation consists principally of small desert shrubs and abundant Yucca or Joshua trees. Water for all purposes is hauled from Patterson Well, 5 miles distant. The richer gold- bearing gravels, as known in June, 1933, occur within an area some 8 miles long by an undetermined width and are confiined mainly to the arroyo- bottoms. They consist predominantly of slabby schist pebbles, with few boulders more than 10 inches in diameter, intermingled with abundant silt and sand. These deposits are generally less than 2 feet thick and rest upon caliche- cemented gravels. Their gold occurs partly as fine material and partly as flat, rugged nuggets that are known to range up to 1/ 16 ounce in weight. Black sand is abundantly associated with it. Northeastward, the gold particles and the gravels become progressively finer grained. 36 Tests of part of the field showed average values of 69 cents per cubic yard. In Most of the testing was done with dry- washers. A few small wet machines were tried, but the water for them WaS found to be too costly. According to M~. Duncan, lO the underlying cemented gravels are also gold- bearmg, but no comprehensive test of them has been made. . Origin: The King Tut placers probably originated from eroSIOn of a group of gold- bearing quartz veins in the Lost Basin Range. The ragg~ dn~ ss of the gold nuggets, many of which carry attached quartz, m( hcates a local derivation. Plate n.- Sampling operations in King Tut placers, 1960. YAVAPAI COUNTY INTRODUCTION Yavapa. i County includes a region of approximately 8,150 square mIles.. Exc~ pt fa: th~ edge of the plateau along its northeastern margm, thIS regIOn IS characterized by north- northwestward- trending mountain ranges and valleys. The largest of these ra. nges, the Br~ dshaw, is approximately 45 miles long by 20 miles ~ lde, ~ nd att~ ms a maximum altitude of 7,971 feet. The region IS dramed. chl~ fly by the Verde, Agua Fria, Hassayampa, and Santa Mafla flvers, of which the lower courses are 1600- 2200 feet above sea level. In general the h~ gher ridges and valieys ~ re w. ell wooded and watered, while the slopes below 5,000 feet m altItude . tet; d to be brushy, and the country below 3,500 feet favors semIafld types of vegetation. 39 Placers have been worked in more than thirty districts or areas of Yavapai County. As the boundaries of these distri. cts are not clearly defined or limited, there has been some confUSIOn regarding the designation of local areas among the statistics reported in the U. S. Mineral Resources Volumes and U. S. Minerals Yearbooks. Descriptions in this bulletin include the more important districts as well as some of the minor ones for which information has been obtained. EARLY HISTORY Discoveries of gold in Yavapai County were announced by two expeditions during 1862- 63. One of them, guided by Pauline Weaver and including Major A. H. Peeples, located the Rich Hill placers, while the other party, headed by Capt. Joseph R. Walker, found placer and lode gold deposits in the Lynx Creek, Hassayampa, Big Bug, Groom Creek, and Granite Creek areas. Some fifteen or twenty years earlier both Weaver and Walker had trapped extensively in Arizona and probably had become aware of areas favorable for prospecting. On May 10, 1863, the Walker party organized the Pioneer placer mining district to include " certain portions of Oolkilsipava River and its tributaries." 2o A month later it was extended to the " Francisco ( Verde) River on the east, to the divide of the river Aziamp ( Hassayampa) and Antelope Creek on the west, and to include the Agua Fria River and its tributaries." 21 Each placer claim was to be 300 feet long by 150 feet wide. Prescott, originally a settlement chiefly of placer miners, became the Territorial capital in 1864. . PRODUCTION The value of production from Yavapai County gold placers prior to 1900 is conservatively estimated at $ 4,000,000. After 1929, interest in these placers was greatly stimulated by the financial depression; owing largely to mechanized methods and also to numerous small- scale operations, their value of output rose to $ 379,800 for the year 1941. It receded during World War II and for 1949 was $ 15,505. The recorded yield of gold from placers in Yavapai County amounted to $ 241,510 for 1905- 31 and $ 1,701,728 for 1932- 49, or a total of $ 1,943,238 for 1905- 49. LYNX CREEK PLACERS Physical features: The Lynx Creek placers are in central Yavapai County, along Lynx Creek from near Walker, 7 miles southeast of Prescott, to its junction with Agua Fria Creek, 13 miles east of Prescott. Lynx Creek, which flows northward between foothill ridges of the Bradshaw Mountains, and northeast and eastward through conglomerate terraces of Lonesome Valley, has an approximate length of 18 miles. Since it extends between elevations of about 40 .... .... .. cg ell U I. HH H 41 7,000 and 4,600 feet above sea level and drains a large, high region, it receives a considerable amount of water each season and is perennial in its upper, pine- wooded course. At Prescott, which is about 5 miles west of the creek at an elevation of 5,320 feet above sea level, the normal annual fall of rain and snow water is 18.52 inches, the highest temperature recorded was 105 degrees, and the lowest 12 degrees below zero. 22 Early history and production: According to former State Historian Hall, lo the Lynx Creek placers were discovered in 1863 by a party of California miners headed by Capt. Joe Walker. As the news of their discovery filtered back to California, the number of placer miners on Lynx Creek increased to 200 or more. Active work, with hand rockers, pans, and small sluices, continued along the stream fOT several years before exhaustion of the richest gravels. Like most placers of the Southwest, unfortunately, no records of the early- day yield are available, but Lynx Creek is noted as ope of the most productive gold- bearing streams in Arizona. Raymond9 reported its 1874 production at $ 10,000, and Hamilton4 estimated the total prior to 1881 at $ 1,000,000. According to A. C. Gilmore, lO of Prescott, about 100 men were working the Lynx Creek placers prior to 1885, and some of them recovered about $ 20 per day. W. R. Shananfelt, 1° of Prescott, stated that one man recovered $ 3,600 in eleven days from the lower reaches of the creek. Dredging operations: In the late eighties, B. T. Barlow- Massick built a small dam above the present Prescott- Dewey highway bridge, installed a few miles of 30- inch pipe, and did some hydraulicking, but a flood destroyed the dam. About 1900, the Speck Company tried out an old dredge a short distance below the bridge, but the roughness of the bedrock there prevented its success. Later, G. S. Fitzmaurice operated this dredge farther down the creek, but, after recovering about $ 800 worth of gold, the dredge fell apart. A large patented gold- saving machine was tried out nearby at about this time, but also without success. In 1927, Lynx Creek Mining Company attempted large- scale operations with a moveable plant consisting of an Insley excavator, a Barber Green stacker, screens, and sluices. During 1932 a California- type dredge ( Plate II.) was installed in the lower Lynx Creek placer area, on the G. S. Fitzmaurice property, below the dam illustrated in Plate III. The dredge was 50 feet long by 35 feet wide by three stories high and had a capacity of 100 cubic yards per hour. It drew 30 inches of water and normally required about 85 gallons of new water per cubic yard of gravel treated. Approximately twenty men were employed to conduct the operation three shifts per day. Calari Dredging Company operated this dredge during MarchJuly, 1933, and in sixty- one days treated 60,000 cubic yards of gravel which yielded approximately 32 cents per cubic yard. In June of that year, the dredging was being carried on to an ap- 42 proxi~ ate depth of 6 feet. The gravel, as mined with a 1l, 2- yard draghne shovel, was. passed through a lO- inch grizzly, then through a trommel wlth a 5- 16- inch screen, whence the oversize went to a stacker, and the undersize into a sluice equipped with 400 square feet of angle- bar riffles. I Of the total gold in the gravels, from 85 to 90 per cent was ~ xtr~ cted. It ranged in size from flour up to fragments 0.1 inch m dlameter and was accompanied by abundant black magnetic sand. Subsequent dredging operations in the Lynx Creek area may be summarized as follows: Arizona Dredging and Power Company, latter part of 1933. L~ n~ Cree~ Placer Mine Company, 1934- 40. With large floatmg washmg plant and two draglines, treated 556,115 cubic yards of gravel in 1938 and 542,815 cubic yards in 1939. Was largest producer of placer gold in Arizona Phoenix Lynx Creek Placers Company, 1934: Rock Castle Placer Mines Company, fast quarter of 1939. Handled about 12,000 cubic yards of bench gravel by means of a dr: y- Iand. dredge equipped with four bowl- amalgamators. Placer KlI~ g Mmes, Inc., in September 1940 took over property and equlpment of Lynx Creek Placer Mine Company Big Bug Dredging Company 1941. . Minona Mining Company, 1948- 49. Other dredges at one or two properties, 1940- 42. . Small- scale op~ l" 8tions: Intermittent small- scale placer minmg ~ as been ca~ rled . on in the Lynx Creek area for many years, parbcularly durmg bmes of depression. In the spring and summ~ r of 1933, for example, approximately thirty men were recoverm~ gold. by rocking and sluicing there. Most of the gravel was obtamed m small dry. side- gulches and packed to water. In places, trees were bein~ unrooted in order to reach pay dirt beneath them. A short dlstance below the Dewey highway bridge one man : was drifting on old side- gulch channels. ' Accordmg to A. S. Konselman, lO of Prescott, who kept accurate reco~ ds of the gold produced by these operators, the average earnmgs per man amounted to 50 cents per day. Production since 1900: The total value of production from the Lynx Creek placers, including the Walker area, since 1900 ~ as b~ en on the or~ er of $ 1,000,000. For the period 1914- 31, as hsted l? the U. S. Mmer~ l Resources, it was $ 27,373. For 1933- 49, accordmg to the. U. S. Mmerals Yearbooks, it amounted to $ 903, 604, most of wh~ ch was recovered prior to 1942. Geology: In lt~ south~ rn or uI? per reaches Lynx Creek flows across. pre- Cambnan schlst, gramte, and other intrusive rocks. In the. northeastern portions of the area these older rocks are overlam by conglomerate of medium- grained, fairly well- rounded gravels, firmly cemented in sand and volcanic ash. This conglomerate, which constitutes the bedrock of the placers of lower Lynx Creek, appears to be overlain on the west by late Tertiary basalt of Bald Hill. The youngest formation consists of gravel, sand, and boulders that occupy the bed and flood plain of Lynx Creek. This material, which contains the placer gold, is generally well- rounded except in the upper reaches of the stream. From near Walker to a point about 8 miles in air 1ine downstream, or 2 miles below the Dewey highway bridge, the placers occur as thin relatively narrow benches or bars. Downstream from that point, in the bottom of the steep- walled gulch formed in the conglomerate fill of Lonesome Valley, the placers attain a maximum width of over 1; 8 mile and a thickness of 8 to 24 feet. Although some gold is present throughout this thickness, the richest material commonly is at the conglomerate bedrock and in a streak 4 feet thick about 2 feet above the bedrock. Lindgren23 states that the average value is reported at 18 cents per cubic yard. " At Walker the placers yielded nuggets worth as much as $ 80, at about $ 16 an ounce. Lower Lynx Creek produced a finer- grained gold of higher value, worth about $ 18 an ounce. Such an enrichment in the value of the gold is common and indicates a solution of the silver by the waters." The gold of lower Lynx Creek ranges from finely divided material up to $ 6-$ 8 nuggets, and is associated with considerable hematitic and magnetitic black sand. The placer gold of Lynx Creek apparently was derived from disintegration of numerous gold- bearing quartz veins contained in the pre- Cambrian rocks of the Walker area. WEAVER AND RICH HILL PLACERS Physical features: The Weaver and Rich Hill placers are in southern Yavapai County, a short distance northwest of Octave and 6 to 8 miles east of Congress Junction. This placer area is at the southern margin of the Weaver Mountains, which rise to more than 5,000 feet above sea level or more than 2,000 feet above the adjacent desert plain on the south. Rich Hill attains an elevation of 5,200 feet above sea level between the deeply eroded canyons of Antelope Creek on the west and Weaver Creek on the east. Since the higher portions of the Weaver Mountains receive at least 18 inches of rainfall per year, these two south- flowing creeks often have some water in their upper courses and are subject to torrential floods during rainy seasons. History and production: In the early sixties a party consisting of Capt. Pauline Weaver, Maj. A. H. Peeples, and others, happened to camp at the base of Rich Hill, after their guide had deserted them on the desert north of Wickenburg. A Mexican of the party, while looking for their strayed animals, discovered loose gold nuggets on top o'f Rich Hill. This discovery led also to the finding of placers on Weaver and Antelope creeks. This whole area soon became the scene of intense activity, and in five years, according to Hall, lO produced about $ 500,000. The loose gold underneath boulders and in crevices of rocks on Rich Hill was easily gathered, but more effort was required to work 44 I the ~ ouldery gravels of Weaver and Antelope creeks by panning, ! rockmg, and sluicing. As much as $ 40,000 is said to have been taken from a certain acre, and the production of the whole area prior to 1883 was estimated by HaJl1ilton4 at $ 1,000,000. The town of Weaver, on Weaver Creek, flourished until about 1896 but is now marked only by crumbling ruins.. Blake, in 1899, stated that the score or so of men who were working these placers from year to year were supposed to be recovering over $ 2.000 per month. The value of known output from the Weaver and Rich Hill : placers since 1900 has been approximately $ 150,000, of which $ 83,975 was recorded for the years 1905- 31, and $ 62,049 for 1934- 49. According to the late Carl G. Barth, Jr., 10 the yield for the year prior to June, 1933, was valued at about $ 1,800. Approximately fifty men were carrying on sluicing and rocking in this field during the winter of 1932- 33, but their. number decreased to eighteen with the advent of summer. Because the gravels are mostly coarse ( Plate IV) and have been repeatedly worked, the average daily earnings were not more than 30 cents per man. Minor amounts of dry- washing have been carried on in the vicinity of Oro Fino Gulch, in the · southernportion of the area. In~ 938 th~ chief producer was Universal Placer Mining C? rporation, whIch operated a power . shovel and dry- concentratmg plant at the Thunderbird property. Geology: The Weaver Mountains are made up mainly of old granite and schist, overlain in places by younger sediments and lava. These mountains contain the Congress, Fool's Gulch, Octave, Yarnell, and numerous smaller gold- bearing veins. The placer ground covers an area of approximately 8 by 5 miles. According to local people, the most productive portions were in the northern half of this area and included about 10 acres on top of Rich Hill; portions of the sides of Rich Hill; channels and benches of Weaver, Antelope, and other washes; and gravel benches that lie between these washes. ~ ich Hill, which rises steeply for about 2,000 feet above the plam, consists of : ather ~ ntensely jointed granite. In places, it IS traversed by thm, lentIcular quartz veins which carry pyrite, galena, and gold. The top of this mountain is a hilly mesa about ~ 8 mile long by % mile wide, that evidently represents ~ n ero~ lOnal remnant of the elevated Weaver Mountain pediment. It Includes several acr~ s of broad, shallow b. asins and drainage channels whose gramte floors are mantled WIth granite boulders and very thin, rusty, sandy soil. A few angular pebbles of quartz and of hematite are locally present. The once- abundant occurrence of placer gold within the shallow basins and drainage channels is proclaimed by numerous old workings that scoured every square foot of their surface. ( See Plate V.) Along washes and benches below Rich Hill, the placer material consists of iron- stained gravel and sand, up to 10 or more feet Plate IV.- Typical gravels of Weaver Creek placers. thick, together with abundant subangular boulders that are 2 to 6 feet in diameter ( Plate IV). Character' of the gold: According to Heikes, 14 the fineness of the Rich Hill and Weaver placer gold is 910. On Rich Hill, according to Blake, 24 one nugget worth $ 450, and three worth a total of $ 1,008. were found. C. B. Hosford, l° of Octave, stated that the largest nugget found on upper Weaver Creek was worth $ 396, and that two chunks of quartz contained $ 450. In the spring of 1931, a large nugget was brought into the office of the Arizona Bureau of Mines from the Weaver region. This nugget was described by Heinerhan25 as follows: The nugget is in general outline shaped somewhat like a human molar. It measures approximately 53 mm. across the widest portion of the ' roots,' and 47 rom. from the bottom of the ' root' to ' the crown.' Several fragments of slightly iron- stained quartz remain in the center of the mass. The total weight is 270.90 grams, and it may be calculated that the nugget consists of 252.38 grams of metal and 18.52 grams of quartz ... worth $ 152.62 in gold and 22.71 grams of silver worth 21 cents at date of writing. During the 1932- 33 season, a few nuggets ranging up to more than 3 ounces each in weight were obtained from Weaver Creek. Two nuggets, each weighing more than 5 ounces, were found on upper Antelope Creek. Away from the margin of the mountains, coarse gold becomes progressively more rare. 46 Plate V.- Top of Rich Hill in 1933. Origin: These placers probably were derived by erosion of many small veins within the vicinity and concentrated by local streams. Such large, angular boulders ( Plate IV) and such generally coarse gold could not have been transported far in ancient river channels. COPPER BASIN PLACERS Gener~ l features: The Copper Basin placers are north of Copper BaSIn Wash, between Skull Valley and the Sierra Prieta. They are accessible from the Santa Fe Railway at Skull Valley and Kirkland by a few miles of road. Here, a plain slopes southwestward from an elevation of 5,500 feet at the base of the Sierra Prieta to 4,000 feet at the junction of Skull yalley and. Copper Basin Washes. Most of this plain is ~ oored WIth extenSIve deposits of gravel, sand, and clay, locally mterbedded and mantled with volcanic tuffs and flows, but its easternmost 1 to 3 miles of width is a pediment that has been carved on granite. The whole area is dissected by many southwestward- trending gulches which are tributary to Skull Valley Wash. Part of Copper Basin Wash carries a small flow of water throughout the year, but the other gulches are dry except for occasional short periods. The bedrock of the placers generally consists of cemented gravels, but, in certain areas relatively far from the mountains it is hard clay. ' The gold- bearing gravels are made up largely of granitic sand together with various amounts of boulders and clay. Near the mounhlins. thp. houldp. rs are rp. lativelv abund: mt and coarse but. 47 in the western part of the area, they are mostly less than one foot in diameter and constitute a small percentage of the gravels.. The clay content is erratically distributed, but tends to be relatively greater towards the western part of the area, except near Copper Basin Wash where sand predominates. The gold- bearing gravels form a relatively thin mantle on the ridges, but range in thickness from 3 or 4 feet up to 15 or mo~ e feet in the gulches. They contain some gold throughout theIr thickness but generally are richest in a thin streak at or near bedrock. Widely distributed tests indicate that much. of the ground within this field contains from 50 to 83 cents 111 gold per cubic yard. . The gold, which is from 925 to 950 fine, occurs as particles th~ t range in size from small specks up to nuggets several ounces m weight. In the western part of the field, nuggets worth more than 25 cents each are rare. Near the mountains, the gold fragments are characteristically wiry to angular and coarse. Associated with the gold is abundant mag: t; e~ itic black sa~ d. In the upper portion of Copper Basin Wash, OXIdIzed copper mmeraIs are commonly present. Throu~ hout the southwestern portion of the field, small particles of cmnabar ( mer~ ury sulphIde) and natural amalgam, which were doubtless . derIved from the cinnabar veins of Copper Basin, are apparent m the placer concentrates. Erosion of gold- bearing veins of the Sierra Prieta, partic~ larly in the pediment area, provided the gold of the Copper Basm placers. The increase in angularity and coarseness of the gold towards the mountains indicates a local derivation. History and production: The Copper Basin pla~ ers, which had been intermittently worked in a small way pnor to 1929, began to attract renewed interest with the advent of the depression. During 1932, three concerns carried on large- scale operations in the Copper Basin placers. In the southwestern part of the field, the ~ orback and E~ ston and Smith companies ran separate concent~ atmgplants, equIpped with power shovels, trommels, screen, DIester- type tables and amalgamators, which had capacities of 350 or more yards per eight hours. Water for these plants was pumped from shallow wells and re- used as much as possible. The Forback & Easton plant closed down in the fall of 1932, and was taken over by R Cassendyke. Its production is reported to have been from $ i2 000 to $ 15 000 worth of gold, most of which was in particles wo~ th less th~ n 25 cents each. The Smith Company was succeeded by Gold Star Placer Company, ~ lso contr? lled. by Mr. Cassendyke. Its plant, which was resummg operatIOns m June, 1933, is illustrated in Plate VI. During April and May, 1932, a lessee operated a Ph- yard power shovel and a Girand. barrel concentrator on ground in Mexican Gulch, about 2lh mIles from Skull Valley. According 48 to Mr. Lyda, l° he recovered approximately $ 5,000 worth of gold. Some $ 15 nuggets were found, but most of the gold ranged from $ 3 nuggets down to particles as small as a mustard seed. In June, 1933, Operators and Developers Company had installed in the northeastern part of Copper Basin a plant with a rated capacity of 500 cubic yards per twenty- four hours. This plant was equipped with a vibrating grizzly, washing trommel, vibrating screens, sluice boxes, and Wilfley and Diester- type tables. Water was to be pumped from the Lorna Prieta mine shaft, about 1 mile farther south. The placer gravel was to be mined from an adjacent gulch. During the year prior to June, 1933, from fifty to sixty smallscale, individual operators recovered gold mainly with rockers ( Plate XI) and small sluices in Copper Basin Wash. According to A. S. Konselman, 10 of Prescott, the daily earnings per man ranged from 25 cents to $ 1 and averaged about 50 cents. The U. S. Minerals Resources credit the Copper Basin placers with a production valued at $ 1,023 for the year 1931. The yield for the year prior to June, 1933, as estimated by G. L. Lyda, lO of Kirkland, amounted to about $ 31,000, of which $ 26,000 came from large- scale operations. The output for 1949, as reported in the U. S. Minerals Yearbooks, was valued at $ 27,972. Thus the total production for 1931- 49 was on the order of $ 60,000. BIG BUG PLACERS Physical features: The Big Bug district is in south- central Yavapai County, in the general vicinity of Big Bug Creek, Mayer, Poland, McCabe, and Humboldt. This region includes a pediment at the northeastern foot of the Bradshaw Mountains and extends up local gulches. Big Bug Creek generally has water in approximately the upper half of its course. History and production: Gold was discovered within the Big Bug district in the late sixties, but the greatest activity in placer mining there was during the eighties of the past century. Considerable sluicing, rocking, and panning have. gone on, especially in upper Big Bug Creek as far down as Mayer, and in Chaparral and other gulches near McCabe. Dry- washing has been done to some extent in drier portions of the region. No estimates of the early production are available. In 1926, bullion having a fineness of 0.952 was recovered by sluicing operations of the Uncle Dudley Mining Company. Large- scale operations were attempted during 1932 by Humphries Investment Company of Denver, with a large trackmounted power shovel, a Barber Green stacker, and sluices. In July, 1933, Pantle Brothers began large- scale operations on a 220- acre tract leased from Messrs. Shank and Savoy, west of Big Bug Creek and about 3 miles northwest of Mayer. In August, 1933 they were minipg old placer and mill tailings in a gulch near Big Bug Creek; this material was bouldery to sandy, with but little clay, and rested upon cemented gravels. The gold oc-i' 50 curred as rather irregularly distributed, flat to round and ragged particles which ranged up to about 50 cents each in value. Pantle Brothers' concentrating plant was equipped with four rubber- riffled Ainlay centrifugal bowls ( Plate VII). Fed with a one- yard power shovel, it had a capacity of 1 cubic yard per minute and required about 300 gallons of water per minute. Ample water for this plant was obtained at bedrock. Production during the first forty days of run amounted to about 45 ounces of gold. Four men were employed. Approximately 9,000 cubic yards of gravel were handled during 1933, and the gold produced in 1934 amounted to more than $ 15,000. Subsequent operations in the Big Bug area, as reported in the U. S. Minerals Yearbooks, have been as follows: In 1938 a washing plant equipped with four Ainlay bowls worked at Hill group. Hassayampa River Mining Comp~ ny ran a dragline dredge at Lawson group but suspended operations late in the year. In 1939 dry- land dredging was carried on at the Savoy and Shanks properties, and sluicing was done at the Hill, Johnson, and Caywood properties. During 1940 a dry- land dredge and a ' dragline dredge each worked a few months at the Shanks and Savoy property. Big Bug Dredging Company operated a 2%- yard dragline dredge at the Hill property the last four months of the year and recovered 1,100 ounces of gold. In 1941 Arical Mines, Inc., worked a dragline floating dredge at the Star or Lawson property. Big Bug Dredging Company continued to operate at the Hill property until in March when it ~ oved to the Lynx Creek area. A dragline dredge operated at the Nelson and Fitch property in 1946. Some sluicing was carried on in the district during 1943- 49. Small- scale operations were particularly active during 1932- 33 when, according to the late F. W. Giroux, 1° sixty or more men were placer mining within the area, largely in the gravel benches and side gulches of Big Bug Creek, several miles northwest of Mayer. In this area, which had been rather intensively worked during the past, most of the mining was done by tunnels from which the gravel was packed to sluices, rockers, or small powerdriven concentrating machines. Efforts were handicapped by the large proportion of coarse boulders within the gravels. The recorded gold production from the Big Bug placers amounted to $ 30,751 for 1910- 31 and $ 462,480 for 1934- 39, or a total of $ 493,231 for 1910- 49. Geology: The principal rocks of the Big Bug district are preCambrian schists, smaller amounts of granite and granodiorite, abundant rhyolite dikes, and Tertiary basalt flows. The placers occur in stream channels and on intervening mesas of a roughly triangular area that extends for about 20 miles east and northeast from the head of Big Bug Creek. The gold of the stream placers is generally coarse. One of the largest nuggets found in the Big Bug' region contained about $ 500 worth of gold figured at $ 20.67 per fine ounce. In the gravel mesa between Humboldt and Mayer, the gold, which is rather finely divided and associated with considerable clay, amounts to about thirty to forty cents per cubic yard. Presumably, quartz veins within older rocks of the vicinity provided gold for the stream placers, but the finely divided gold of the gravel mesas between Mayer and Humboldt may have undergone longer transportation. HASSAYAMPA PLACERS Introduction: Placer gold occurs along much of the Hassayampa drainage system in Yavapai County. This creek rises in the Bradshaw Mountains at an elevation of approximately 7,000 feet above sea level, a few miles south of Prescott, and crosses the Yavapai- Maricopa County line two miles north of Wickenburg at an elevation of about 2,000 feet. Owing to its large drainage area, the main creek carries torrential floods in rainy seasons and abundant subsurface water during dry months. History: According to local reports, the greatest period of activity in the Hassayampa placers was from 1885 to 1890. The failure of Walnut Grove Dam in 1880 prevented large~ scale operations that had been planned for a tract downstream from Wagoner. Small- scale, individual sluicing and rocking have been carried on every year, but the total production therefrom is unknown. During the 1932- 33 season, more than fifty men were working the Hassayampa placers of Yavapai County. Most of this activity was confined to the side gulches. In general, the average daily returns amounted to about 50 cents per man. A dragline dredge worked intermittently on the Hobbs property during 1940- 42 and 1946. Production from the Hassayampa placers, as listed by the U. S. Mineral Resources and U. S. Minerals Yearbooks, amounted to $ 3,659 for 1926- 31 and $ 61,568 for 1934- 49. In addition, the Black Rock area was credited with an output valued at $ 2,776, the Blue Tank area with $ 1,609, and the Wagoner area with $ 1,008, during 1934- 49. Geology: The principal rocks of the lower Hassayampa area of Yavapai County are pre- Cambrian granite and schist, mantled in many places by Tertiary gravels and lavas. The upper portion consists of pre- Cambrian schist and granite, intruded by smaller masses of diorite, granodiorite, and rhyolite porphyry. PreCambrian to Tertiary quartz veins within the schist and granite provided the gold that erosion has concentrated in the placer deposits. The gold found along the upper reaches of the creek was generally coarse, but downstream it was progressively finer. GROOM CREEK PLACERS The Groom Creek placers are in south- central Yavapai County along Groom Creek, from 4 to 6 miles south of Prescott. This 54 creek heads in the Bradshaw Mountains west of Walker at an elevation of more than 5,000 feet above sea level and joins Hassayampa Creek at a point about 5 miles in air line farther southwest and 1,900 feet lower. These placers were discovered in the sixties and were actively worked during the eighties. Their total production prior to 1930, according to former State Historian Hall, lO probably has amounted to about $ 100,000. During the past several years, only slight activity has been reported in the Groom Creek placer field, and only small amounts of gold have been produced there. Quartz veins contained within the local pre- Cambrian schist, which has" been intruded by diorite, granodiorite, granite and dikes of rhyolite porphyry, were the original source of the gold of these placers. WALNUT GROVE PLACERS The Walnut Grove placer district, south of Kirkland Junction, includes portions of the Placerita, French, Cherry, Blind Indian, and Mill drainage areas. Throughout a large part of this vicinity, the gulches have dissected a northeastward- sloping pediment of general elevation less than 5,000 feet above sea level. This pediment consists of granite, diorite, and steeply dipping schist, locally mantled by gravel and lava. It contains many small gold- bearing quartz veins. Erosion of such veins probably furnished the gold of the placers. No estimates or records of the early production of this field are available. In 1899, Blake24 stated that " The placers . . . at Placerita have long been known and worked, and are regarded as good- wages mines." According to the late A. B. Colwell, I° a dredging project was attempted several years ago on a small area of ground in French Gulch about 1 mile below Zonia. When water was available during the 1932- 33 season, approximately twenty- five men were placer mining in the vicinity of the junction of French and Placerita gulches, chiefly with rockers and sluices. Their average daily earnings were about 50 cents per man. According to A. R. Evans, l° of Kirkland, the production of this area for the year prior to June, 1933, amounted to approximately $ 2,000. This gold was fairly coarse, with many $ 5 and $ 10 nuggets and one $ 80 nugget. It was worth about $ 18 per ounce at the old price of gold. At the same time, in the upper portion and side gulches of Placerita Creek, three or four men were operating long toms and dry- washers on shallow gravels. They each obtained from 25 to 50 cents worth of coarse gold daily. Large- scale operations were started in June, 1933, on the Maude Lee claims, at the junction of Placerita and French gulches, The plant included a one- yard gasoline shovel, angle- iron riffles, and a barrel amalgamator. Here, the gravels consist mainly of granitic sand with some medium- coarse, flat schist boulders. A small flow of water occurred at bedrock. The Walnut Grove placer areas were credited during 1934- 36 with a gold production valued at $ 9,339. MINNEHAHA PLACERS Placer gold occurs along Minnehaha Creek, about 25 miles in air line south of Prescott, below elevations of 5,000 feet above sea level. Lindgren23 says: Minnehaha Flat is a northward- trending, well. tim~ ered and. watere~ basin on the headwaters of Minnehaha Creek: ~ hlCh dlScha~ ges m~ ~ a~ sayampa River near Walnut Grove, Placer mmmg was earned on ele l~ the eighties of the last century all the way up from the ' Old Log House to the Button Mine, also in branches coming in from the east. ~ he gold was worth about $ 17 an ounce and was extracted by arrastres, ~ IUlces, and dry- washers. The probable production was $ 100,000, accordmg. t? Mr. M. A. McKay, an old- time resident of the district. The fOld is belle\' ed to have been derived from the Fortuna lode near Lapham s place. Placers on Oak Creek, below Fenton's ranch, yielded gold valued at $ 924 during 1935- 40. MODEL PLACERS The Model placers comprise a small area in the vic~ nity of Model Creek on the western side of Peeples Valley. ThIS locality is accessible by some 2 or 3 miles of road whi. ch branches westward from U. S. Highway 89 at a gate % mIle north of Peeples Valley store. These placers have been known for m~ ny years, since the discovery of the M~ del a~ d othe: ~ old- bearmg veins in this vicinity, but comparatIvely ~ Itt1e mmmg of them has been done during the present generatIOn. , Here a granite pediment extends, from elevatIons of 5,000 to 4 500 feet above sea level between the eastern foot of the Wea'ver Mountains and Peeples Valley. This pediment has b~ en dissected to shallow depths by several small eastward- trendmg streams which carry water during only part of. the ye8: r: In pl~ ces between these gulches, it is co? cealed by thm gramtIc detrItus and soil which supports a thIck growth of brush and scrub oaPk. lacer gold occurs in Model and other gulches for some d." IS-tance upstream but the principal gold- bearing gravels bemg worked in June: 1933, occurred in small, local. basins or ch~ nnels on the pediment for a width of about % mIle on each SIde of Model Creek downstream from Pawley's property. . The placer' gravels, which consist mainly of granitic sand ~ Ith some clay and few boulders, are generally less than ~ feet t~ lCk. They contain a little gold throughout, but a~ e richest m a streak 6 to 12 inches thick that rests upon gramte or cemented granitic sand. Partial tests of this pay streak s~ owed about $ 1 in gold per cubic yard. The gold occurs as faIrly rough particles that range up to about lh ounce in weight and are reported to be about 850 fine. It was probably derived by erosion of goldbearing quartz veins in the vicinity. 56 In June, 1933, approximately twelve men were engaged in small- scale placer mining operations in this field. After stripping off the overburden, the pay streak was carefully hand- shoveled and swept from the bedrock and hauled to Model Creek for hand coneentration. BLACK CANYON PLACERS Placer gold occurs along Black Canyon, which upstream branches into Turkey, Poland, Bumblebee, and several other ? reeks and southward drains into the Agua Fria River. Accordmg to Lindgren, 28 Placers have been worked at several places in Black Canyon, particularly belo\~ the. Howard Copper Company's property. A few years ago a Portugese IS saId to have taken out $ 20,000 near the old stone cabin, one mile bel~ w Howard. There are also small placer deposits near Turkey Creek s~ tion, and every year more or less dry washing is done by Mexicans in thIS locality. The placer gravels in much of this field contain abundant coarse boulders. The gold particles are generally flat and fairly coarse. Black sand occurs abundantly in the gravels and adheres to the smaller gold particles. During the cool por~ ion of the 1932- 33 season, about twentyfi,: e . me~, mostly transIents, were engaged in small- scale placer mmmg m Black Canyon, chiefly between Arrastre Creek and Cleator, and to a small extent in American and Mexican gulches. Most of the concentrating was done with rockers and sluices and only a small amount with dry- washers. The average daily returns were very s~ all. W. J. Martin, storekeeper at Bumblebee, purchased approxImately $ 80 worth of gold per month and estimated IO that an equal amount was marketed elsewhere. The largest nugget found during that time came from American Gulch and was valued at $ 14.38. . On a bar some 3 miles south of Bumblebee, a plant equipped WIth a power shovel, screens, and tables was operated for a short time during the summer of 1932. Recorded gold production from the Black Canyon placers during 1934- 49 amounted to $ 12,758. GRANITE CREEK PLACERS Placer gold occurs along the upper branches and main course of Granite Creek, which rises a few miles south of, and flows northwar
Object Description
TITLE | Gold placers and placering in Arizona |
CREATOR | Arizona State Bureau of Mines. |
SUBJECT | Gold mines and mining--Arizona; Hydraulic mining; Placer deposits--Arizona; |
Browse Topic |
Land and resources |
DESCRIPTION | This title contains one or more publications. |
Language | English |
Publisher | University of Arizona Press. |
Material Collection |
State Documents |
Source Identifier | MN 1.3:B 85/168 |
Location | ocm01982150 |
REPOSITORY | Arizona State Library, Archives, and Public Records--Law and Research Library. |
Description
TITLE | Gold placers and placering in Arizona |
DESCRIPTION | This title contains one or more publications. From title page: "by Eldred D. Wilson, Bulletin 168, Reprinted 1981" |
Language | English |
Acquisition Note | Publication or link to publication sent to reports@lib.az.us |
DATE ORIGINAL | 1961 |
Time Period |
1960s (1960-1969) |
ORIGINAL FORMAT | Paper |
DIGITAL IDENTIFIER | gold_bull168_ocr |
DIGITAL FORMAT |
PDF (Portable Document Format) |
REPOSITORY | Arizona State Library, Archives, and Public Records--Law and Research Library. |
Full Text | GOLD PLACERS AND PLACERING IN ARIZONA by Eldred D. Wilson Bulletin 168 Reprinted 1981 - State of Arizona Bureau of Geology and Mineral Technology Geological Survey Branch A Division of the University of Arizona PREFACE TO BULLETIN No. 142 .... Copyright © 1961 The Board of Regents of the Universities and State College of Arizona. All rights reserved. TABLE OF CONTENTS PAGE PREFACE 8 PREFACE TO BULLETIN No. 160 . 8 9 PART I ARIZONA GOLD PLACERS GENERAL FEATURES OF GOLD PLACERS ...........................•.........•...........•....... _... 11 Origin 11 Distribution of Arizona gold placers.................................................... 12 Relatipn to pediments 12 Relation to streams 14 Relation to geology and types of veins.................................................. 14 Yearly rainy seasons of Arizona.............................................................. 15 HISTORY OF ARIZONA GOLD PLACER MINIm;.................................................... 15 Summary 15 Early production 15 Production after 1900 16 YUMA COUNTY ....•...................•.............•.•.••••...•••••••.••.••••.••••••..••..••••••••.•••••••••••••••• 18 Districts 18 Production 18 Gila City or Dome placers 18 I, aguna placers 21 Muggins placers 22 Castle DOIne placers 23 Kofa or S. H. placers.................................................................................. 23 Tank Mountains placers 24 Trigo placers 25 La Paz placers 25 Plomosa. district 29 La Cholla placer area 29 Oro Fino placer area 30 Middle Camp placer area 31 PIOlnosa placer area 31 Harquahala placers 32 MOHAVE COUNTY ............•...................••.........•...........•••.•.••..•.••...•......•........•..••••..• 32 Districts and production 32 Chemehuevis placers 32 Silver Creek placers 33 Lewis placer 33 Lookout placers 34 Wright Creek placers 34 Colorado River placers 34 Gold Basin placers 35 IGng Tut placers 37 YAVAPAI COUNTY ••.......................•......••.•••..•.••••..•••.•.••_ ••••••••••••....••. _................... 38 Introduction 38 Early History 38 Production 39 Arizona Geological Survey The Arizona Geological Survey ( AZGS) became an independent State agency July 1, 1988 in accordance with Senate Bill 1102, which was enacted in 1987. The purpose of the AZGS - to assist the wise use of lands and mineral resources in Arizona by providing scientific and investigative research and information - was essentially unchanged. The ancestral AZGS began in 1881, when the Office of the Territorial Geologist was established by the Territorial Legislature. The primary duties were to collect and provide information about mineral resources. In 1893 the University of Arizona established a testing laboratory, known informally as the " Bureau of Mines." From then until statehood in 1912, Territorial Geologists were also affiliated with the " Bureau of Mines" and the university. A 1915 statute formally established the Arizona Bureau of Mines as a State agency administered by the University of Arizona, continuing, essentially unchanged, the functions of the " Bureau of Mines" and. the Territorial Geologist. Data collection and research activities continued to be · concentrated on mineral resources. Sixty- two years later, in 1977, the Bureau's enabling legislation was modernized and its name was changed to the Arizona Bureau of Geology and Mineral Technology. It continued to be administered as a diVision of the University of Arizona. The Bureau was charged with investigating geologic hazards and limitations, as well as the geologic framework and mineral resources of Arizona, in anticipiltion of population growth and increased competition for and conflict over land, mineral resources, and water. The AZGS publishes maps, books, and reports, which are available for inspection at the AZGS office in Tucson and may be purchased through the mail. The AZGS office includes a library that is open to the public during normal working hours. Arizona Geology, published quarterly by the AZGS, contains summaries of AZGS research, announcements of new publications and theses, and short, generalinterest articles on the geology of Arizona. To obtain copies of this publication, contact the Arizona Geological Survey, 845 N. Park Ave., Tucson, AZ 85719; ( 602) 882- 4795. 12- 88UASOO/ 1839 GOLD PLACERS AND PLACERING IN ARIZONA Arizona Bureau of Mines* Bulletin 168 1961 ( reprinted 1981 and 1988) " currently the Arizona Geological Survey ~ e~~ e; r:~~ tifc~ r~ Ii" ii"'" i~~~~~''''''''''''''''''''''''''''''''''' . ~~~:~;~:~~~~~ fi::=~ · :::~:::::::::::::~::::~::~~~::::::::::::::::::::::::::::::::::::::::::::::::::::: Groom Creek placers __ __ _._.~~~~~~~:~:~::::~:~::~:~~::::~~~:~~:~:~:~:.~ .. Walnut Grove placers . Minnehaha placers . ~~~~ l t~~~ e:~ p" i~~~~~ :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Granite Creek placers ,. Eureka placers . Humbug placers .. other Yavapai placers ::::: , 39 43 46 48 52 52 54 55 55 56 56 57 57 57 SANTA CRUZ COUNTY 81 Production 81 Oro Blanco placers 82 Patagonia or Mowry placers 83 Harshaw placers 83 Tyndall placers 83 Nogales placers 84 Palmetto placers 84 COCONINO, NAVAJO, AND APACHE CoUNTIES , · .. · · .. · · · · · · · · · · · · · · · · · · · · · · · 84 REFERENCES CITED IN PART I 85 PINA~ t~~ J~~ ro~ · · · :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~ anada del Oro or Old Hat placers 61 GRAHAM COUNTY 65 ~ fad~ i~~~ pi";;~.~~~........................................................................................ 65 ...................................................................................... 65 G, u ~~~~:~ i~ J~;;~~~-~_ •-. i! Payson placers 63 ...................................................................................... 64 PART II 90 87 87 87 87 88 88 88 88 88 89 89 87 SEEKING PLACER GOLD ....,. --_ ~ ~ .. , ~ , - -.. SMALL SCALE GOLD PLACERING FACTS ABOUT GOLD . Identification of placer gold , . Color . Specific gravity . Mallea bility and ductility . Solubility . Physical properties of gold . Gravity concentration . Amalgamation . Interfering factors . Size of gold particles . INTRODUCTION . 58 58 58 59 60 61 MARICOPA COUNTY -- - ---.-- _-.-.- . t~! t~~~~~~~~ · ~~~~~~::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Hassayampa placers . Other Maricopa County placers :::::::.:::::::::::::: GREENLEE COUNTY 65 CPrloifdtounc- tiMonorenci , placers . 65 ............................................................................ 65 COCHISE COUNTy .................._- -_ . E1;~~~ i~~~ c~~~~~;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: . g~ fJh~~~ chl~ l~ cse~ · · · ~ i;~~~::: ii:~~~ i~::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~:~~~ n J~~~~ rs : ~:::::::::::::::::::::::::::::::::::::::::::::::::::::::: ••••• _ •• _ _. _' ••• ' u ~.~~ •••••••••• ~ •••• ~ •••••••• ~ •••• ~ •••• PIMA COUNTY .......~~ ~"' ..~ ..~~~ ~ ~ ~.~ ~ _ . Production ~! j~~~~ r;~~~~~~~ i::~~~ i~~~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~~ a: l~: A~:~~ t~ · · Pi"~~~~~ · · · · · · :::::::::::::::::::::::::::::::::::::::::::::::::::::::: . ~~ oa;~~: rl~ f:~: r~ · · · · · · · · · · · · · · · · · :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~~~:~ ~:~ o~ o~~~~ er~;~~~~~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 67 67 67 69 69 70 70 71 71 71 72 77 78 80 80 80 81 81 81 PLACER EQUIPMENT AND METHODS 91 Gra\' ity concentration 91 Panning Utensils 91 Pan, miner's 91 Batea 91 : Miner's spoon 92 Other panning utensils 92 Panning 92 Cleaning concentrates 93 Amalgamation 93 Copper amalgamating pans 94 Instructions for amalgamating copper pans 94 Panning with an amalgamated pan 94 Quantity of gravel that can be panned in eight hours............ 96 Rocker ( Cradle) 96 Capacity 96 Construction details 96 Apron 98 Riffles 98 Hopper or screen box ,....... 98 Slope of bottom 98 Amalgamation 99 APPENDIX SUGGESTED LIST OF EQUIPMENT FOR PROSPECTING IN THE SOUTHWEST 118 Prospecting tools 118 General camping equipment 118 Cooking equipment 118 Medical and first- aid supplies 118 ~ l~~_ t~::.~~:::~~~~:~:~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 1~~ Construction details for knock- down rocker 100 The Long Tom ...................•............................•.............::::::::::::::::::::::::.::::: 100 Operation : : 101 Sl uic~ 1ffl~~ :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: i~~ Slope 104 Water consumption and capacity 104 Amalgamation ....•................................................................................. 105 Clean- ups 105 Small sluices ..........................•............................................................. 105 Wet Methods vs. Dry Methods 107 Dry Concentration 108 Dry Concentrators 109 Blanket 109 Dry panning and blowing 109 Dry- washers 109 Separating Gold from Golci Amalgam III Retorting III Retorts III Charging an amalgam retort 112 Potato method 114 Nitric acid method 115 TABLES AND CONVERSION DATA....................... 116 ILLUSTRATIONS 51 36 38 40 45 46 49 53 60 68 95 103 110 113 13 14 24 27 74 92 92 92 97 101 105 106 107 112 VI.- GOLD STAR COMPANY PLANT, COPPER BASIN . 6. - PAN, GOLD MINEH'S 14. - LONG TOM PLATE FIGURE PLATE VII.- AINLAY BOWL CONCENTHATOR, PANTLE BROS. LEASE, BIG BUG CHEEK . PLATE VIlI.- NUGGETS FROM YAVAPAI COUNTy . PLATE lX.- TypICAL PLACER WORK ON SAN DOMINGO WASH · · · · · PLATE XIlI.- DRY- WASHER . PLATE XIV.- RETOHT ( HOMEMADE) . FIGUHE 1. - INDEX MAP SHOWING LOCATION OF ARIZONA GOLD PLACEHS FIGURE 2. - IDEAL CHOSS- SECTIONS OF MOUNTAIN PEDIMENTS . FIGUHE 3 - GEOLOGIC MAP OF KOFA OR S. H. PLACER AREA.. PLATE X.- GOLD GULCH MINING COMPANY OPERATIONS, TEVISTON DISTRICT . PLATE XI.- ROCKER IN OPERATION . PLATE.. XII.- SMALL SLUICE IN OPERATION . FIGUR~; 7. - BATEA FIGUHE 8. - SPOON, MINER'S . FIGURE 9. - ROClU; R, KNOCKDOWN . PLATE L- MoTOR- DHIVEN DRY- WASHER, SEARLES GROUP, GOLD BASIN PLATE Il.- SAMpLING OPERATIONS IN KING TUT PLACERS . PLATE IlI.- DREDGING OPERATION ON LOWER LYNX CREEK. . PLATE IV.- TypICAL GRAVELS OF WEAVER CREEK PLACERS . PLATE V.- Top OF RICH HILL . FIGUm: 4. - GEOLOGIC MAl' OF pAHT OF DOME ROCK AND PLOMOSA MOUNTAINS . . FIGURE 5. - GEOLOGIC MAP OF GHEATERVILLE PLACER AREA .. FIGUHE FIGUHE 11. - RIFFLES . FIGUHE 13. - SLUICE LAY- OUT FIGURE 14. - RETOHT FIGURE 12. - SLUICE BOX, SMALL . 116 116 116 116 117 117 Troy weights and equivalents........... . . Troy weights and measures . Equivalents . Liquid volume and capacity equivalents . Weights of materials . PART III SELLING GOLD . OpEHATIONS DURING 1951- 1961 119 ARIZONA PLACER PRODUCTION 1951- 1959................................................... 120 INDEX 121 PREFACE Although the yield from placers in Arizona has been relatively small through the past several years, public interest in gold increased greatly in 1960, and the Arizona Bureau of Mines now receives numerous requests for information concerning this precious metal. The Arizona Bureau of Mines Bulletin No. 160, Arizona Gold Placers and Placering, Fifth Edition, Revised, was published in 1952. However, it has not been available for general distribution since 1959. This present Bulletin No. 168 supersedes Bulletin No. 160 in the publication series of the Arizona Bureau of Mines inasmuch as it represents a thorough modification of the subject matter of the earlier bulletin and, also, it contains supplemental information which serves to bring statistical data up to date. J. D. Forrester Director October, 1961 PREFACE TO BULLETIN NO. 160 The Arizona Bureau of Mines Bulletin No. 142, ARIZONA GOLD PLACERS AND PLACERING Fourth Edition which W3S written in 1933 and republished in 19: 31, has been out ' of print for the past two years. For 1932 to 1950, the output of placer gold in the State was more than d? uble the amount produced during 1900- 1931. Owing pa~ tly to thIS fact and partly to a public interest in gold, the ArIzona Bureau of Mines continues to receive numerous requests for information regarding placers. This Bulletin No. 160 represents a revision of the Bulletin No. 142, with addition of data from the U. S. Bureau of Mines Minerals Yearbooks and material accumulated by the Arizona Bureau of Mines. T. G. CHAPMAN PREFACE TO BULLETIN NO. 142 The first publication of the Arizona Bureau of Mines on Arizona Gold Placers was written by M. A. Allen and appeared in 1922 as Bulletin 118. It was mainly a compilation of data already in print, but scattered and difficult to find. The stock of this bulletin was exhausted in four years. Eldred D. Wilson, Geologist with the Bureau, was then commissioned to rewrite the bulletin, adding what new data could be obtained. Assisted by W. R. Hoffman in the field and further aided by the advice and suggestions of Carl Lausen, then Geologist with the Bureau, Mr. Wilson completed his work in the summer of 1927, and a large edition was published at once as Bulletin 124. Conditions with which everyone is familiar developed within two or three years, and so much interest was shown in gold that the demand for this bulletin was extremely heavy, and the supply was exhausted before June of last year. A new and greatly enlarged bulletin, No. 132, was prepared at that time, and, although five thousand copies were printed, they have all been distributed. The present bulletin does not differ radically from No. 132, but many parts of that bulletin have been rewritten and an attempt has been made to bring the information obtained therein up to date. Eldred D. Wilson made the field investigations required to secure this new data, and at least a dozen additional districts are described in the present bulletin. Part II has been presented by G. R. Fansett to thousands of people who have attended short courses for gold prospectors, which he has conducted in centers of population all over the State during the past year or two, and experience has shown that the information conveyed is very useful, especially to inexperienced persons. With the exception of very recent discoveries, in spite of diligent efforts to gather all the information available, the descriptions of Arizona placer fields are incomplete and otherwise unsatisfactory. It could, however, hardly be otherwise. The pioneer prospectors and miners were too busy overcoming obstacles, struggling against hardships and celebrating occasional periods of good fortune to write about their experiences, even if able to do so. Few authentic records of most of the earlier camps exist. Available statistics are often far from reliable, and good judgment is required to separate the true from the' false. Anyone who secures a copy of this bulletin with the idea of obtaining therefrom such data as will enable him to engage profitably in placer mining in Arizona should remember that gold placers are usually the first deposits found and exhausted in every region. Prospecting for placer gold is not expensive, and a deposit once found can be worked with little capital unless dredging is necessary. Even hydraulic operations ( which are not described in this bulletin because it is doubtful if any deposits that can be worked satisfactorily in this way exist where the ~ equisite water is ~ vailable) do not ordinarily require the expendIture of a! ly consIderable sum for equipment unless the water must ~ e pIped or flumed long distances. Because placer gold can ~ e easIly and cheaply recovered where water is available, it is not lIkely that unworked ground of fairly good grade remains, at least al~ ng streams which flow for several months a year. People attemptmg to do placering in such districts must therefore ordinarily be satisfied to work ground where the' difficu1tie~ encountered, such as the prevalence of huge boulders, were too great or the grade of gravel was too low to attract the old- timers. Hundreds of people are, however, trying to earn wages on such ground now. Although there is undoubtedly much placer gold in the socalled " desert" regions of southern Arizona the lack of water both for placering operations and for use in the camp, is a seriou~ ? rawback there, as are also the cemented conditions of the gravel m several areas. Many types of dry- washers have been tried in these regions, usually with very indifferent success for reasons outlin. ed in this bulletin, and the high summer temperatures that pre- yaII there should deter anyone from prospecting in these areas durmg the summer months unless he is accustomed to the conditions he will encounter and knows how to meet them. Recent field investigations made by Eldred D. Wilson reveal the fact that the average daily recovery of each experienced pla~ er . miner ~ n the State is probably less than a dollar a day, whIle mexperIenced persons are averaging less than 25 cents a day. Of cour~ e these statements m~ an that a few are doing fairly well, a larger .!?- umber are earnmg expenses, and the majority are not recovermg en~) Ugh . gold to buy food. Rumors that good ~ ages can be made m thIS way, therefore, should be heavily dIscounted. A person not in robust health or one who has not sUfficien~ funds to fin~ nce his entire trip runs a splendid chance of starvmg to death If he tackles placer mining in Arizona. If, however, a man in good health is out of work, has enough money to pay camp e: x; pense. s fo~' some time, and is willing to work hard, a prospectmg tnp WIll doubtless prove preferable to lying around and doing nothing, but it should be taken with the full realization that it is highly probable that little gold will be found. Of cou. r: se, some ric~, virgin ground may be found, but the chance of makmg such a dIscovery is small. It is this chance, however, that has actuated all prospectors and led to the discovery of most mineral deposits. August 15, 1933 G. M. BUT'LER PART I ARIZONA GOLD PLACERS By ELDRED D. WILSON Geologist, Arizona Bureau of Mines GENERAL FEATURES OF GOLD PLACERS ORIGIN Gold placers, or deposits such as gravel and sand which contain notable concentrations of gold, all result from the slow milling and concentration processes incident to natural erosion of pre- existing gold- bearing rocks. The origin of many gold placers is traceable directly to auriferous veins, lodes, or replacement deposits which, in most instances, were not of high grade. According to Emmons, l placers are not apt to form from goldbearing outcrops that contain abundant manganese, iron sulphides, and chlorides, unless precipitating agents such as calcite, siderite, rhodochrosite, pyrrhotite, chalcocite, nepheline, olivine, or leucite are abundant, or unless erosion is very rapid. In other words, the gold may be dissolved and carried below by means of natural chlorination processes that are established when solutions containing chlorides, together with sulphuric acid from the oxidation of iron sulphides, act upon manganese dioxide; but this process is neutralized if precipitating agents are present, and may be ineffective if erosion is very rapid. According to Lindgren,~ the best conditions for concentration of gold into placers are found where deep decay of the rocks has been followed by slight uplift. As the rocks of a region break up under weathering, rainfall washes away most of the resultant detritus, grinds it by striking and rubbing it together and by dragging it along stream beds, and liberates most of the included gold. Because gold is six or more times heavier than ordinary rock. the liberated particles of gold will concentrate along the bottom and come to rest where the stream gradient lessens. The coarser particles will settle down first, and the fine and flaky gold will be carried farther along. The best placer concentrations probably occur in rivers of moderate ( about 30 feet per mile) gradient, under nicely balanced conditions of erosion and deposition. Except where gravel bars may form in slower reaches, particularly within the arcs of curves, very little concentration will take place in gorges. Such bars, through further deepening of the channel, may be left as elevated benches. Most of the gold in a placer generally rests on or near the bedrock. In some instances, the coarser gold is scattered through the lower 4 to 20 feet, or the gravel may be richest a few feet above bedrock, but never is the richness equally distributed IRefprences are listed numerically at end of Part 1. Figure I.- Index map showing lGlcation of Arizona gold placer districts. 40. Catiada del Oro. 41, Clifton- Morenci. 42. GUa River. 48. Alder Canyon. 44. Qu! jotoa. 46. Papago. 46. Armai'! l08a. 47. Old Baldy. 48. Greaterville. 49. LaB Guijns or Arivaca. 50. Tyndall. 51, Harshaw. 52. Patagonia or ' Mowry. Palmetto. 58. Nogales. 64. 01' 0 Blanco. 65. Tevistoll. 56. DOH Cabezas. 57. Pearce. rift Glee." on. 59. Gold Gulch ( Bisbee). 60. Huachuca. ----- I-----:-~ · _-\ I · I' ,, I · iI ,\ i · I 0' Ii - i_---,\' ! Fj I \ I" i" : r:' I ,~ ! 21. Granite Creek. 22. Lynx Creek. 23. Copper BlUlln. 24. Groom Cteek. 25. Big Bug. 26. Hassayampa ( Yavapai Couhty). 27. Model. 28. Placerlta. 29. Weaver. Rich Hill. 30. Minhehaha. 31. Black CanYon. 32. Humbug. 33. Vulture. 34. Hassayampa ( Maricopa County). 35. San Dominga. 36. Payson. 37. GlobL~' Miaml. : IH. Dd! lping Spring. 39. BUI · hnro~ 8a. p-------- I, ! -.....-....... -. -, i .............................. 1. Gila City ( Dome). 2. Laguna. 3. MugglnB. 4. Castle Dome. 6. Kofa or S. H. 6. ' rank Mountains. 7. Tri~ w. 8. Lu PIll.. 9. LI1 Cholla. Oro FIno. Middle Camp. 10. Plomosa. 11. Harquahala. 12. Chemehuevis. 13. Silver Creek. 14. Lewi:->. 16. Lookout. 16. Wri" hl Creek. 17. Willow Beach. IH. Gold Basin. In. King' Tut. 20. Ellft'lcn. 12 vertically. Among the best types of bedrock are compact clays, somewhat clayey, decomposed rock, and slates or schists whose partings form natural riffles. Smooth, hard material does not catch or retain the gold effectively. Gold works down for some distance into minute crevices of hard rock, for 1 to 5 feet into pores of soft rock, and for many feet along solution cavities of limestones. According to Lindgren, 2 crystallized gold, which is sometimes found in placers, indicates close proximity to the primary deposit. He states that there is probably no authenticated case of crystallized gold occurring in gravels which have been transported far, and that it is difficult to believe the assumption that such crystals are formed by secondary processes in the gravels. The high insolubility of gold in most surface waters is demonstrated by the fact that flake or flour gold, which commonly is in 3,000 particles per one cent's worth, may be carried by rivers of moderate gradient for hundreds of miles. The fineness, or parts of unalloyed gold per thousand, of placer gold is generally greater than that of the vein gold of the same district. This increase in purity, which is proportional to the distance that the placer material has been transported and to the decreasing size of the grains, has been shown to be due to solution and abstraction of silver by surface waters. DISTRIBUTION OF ARIZONA GOLD PLACERS Owing to the presence of gold- bearing rocks in most mountain ranges of the Southwest, gold placers which have been of economic importance occur in every county of Arizona except Apache, Coconino, and Navajo. As indicated on the accompanying map ( Figure 1), the placer districts of Arizona that have been notably worked are in the southwestern mountainous and desert half of the State. Many placers occur in gulches that issue from the numerous mineralized areas throughout this region. RELATION TO PEDIMENTS A pediment, as defined by Bryan, 3 is a more or less hilly plain, carved on solid rock and largely without alluvial cover, at the base of a desert mountain. The mountain slopes of a semi- arid region tend to have a steep profile. Most of the dissected basins or fiats that interrupt steep mountain slopes in this region prove, upon analysis, to be related to elevated pediments. The gold placers of Arizona, with the exception of a few that occur within mountain valleys or gulches, are related to pediments. The gold- bearing gravels occur not only in gulches and old channels which traverse or issue from pediments, but also, in many cases, as mantle upon the pediment itself. This relation may be explained as follows: As previously stated the best conditions for the concentration of gold into placers are where deep decay of the rocks has been followed by slight uplift. When removed by erosion, decayed rocks tend to liberate their heavy minerals within sufficiently short space to promote concentra- 14 Figure 2.- Ideal cross- section of mountain pediments. ( B) represents the effect of renewed uplift and long erosion upon ( A); the pediment of ( A) has been more or less dissected, and a newer one has been formed at the base of the mountain. tions. Undecayed rocks, on the other hand, are broken up by mechanical erosion which does not tend to release the heavy minerals with sufficient uniformity to produce placer deposits. In arid regions, mechanical erosion generally keeps ahead of notable rock decay on steep slopes but falls behind such decay on the the gentle slopes of pediments. RELATION TO STREAMS Most of the streams that have formed gold placers in Arizona were small, intermittent, and subject to torrential floods. Hence, placers of economic importance have been found to extend only for a relatively short distance downstream from mineralized pediment areas. Because of the intermittent character of the streams, many of the placers contain part of their gold more or less eratically distributed through a considerable thickness of gravel. In general, however, the richest material occurs at or near bedrock, especially where the bedrock surface forms natural riffles or contains irregularities such as potholes. Particularly along some of the larger streams, notable placers occur as elevated bars which were deposited within the inner arcs of curves. RELATION TO GEOLOGY AND TYPES OF VEINS The principal gold placers of Arizona are associated with areas of crystalline rocks, such as schist, granite, and gneiss, where the veins tend to be of the deeper- seated mesothermal and hypothermal types. 15 Gold- bearing veins of the shallow- seate. d or epithermal t. ype, which occur particularly in areas of volcamc rock, have not yIelded placers of notable economic importance. YEARLY RAINY SEASONS OF ARIZONA The advent of rain is of great importance to the placer miner in Arizona. It exposes nuggets and provides temporary water for wet methods of concentration, but it hinders the dry- washer, whose dirt must be dry. Usually in Arizona, as in much of the Southwest, the least rain falls in May and J~ ne . and the m? st during July, August, and the win~ er. Often thIS ram comes WIth local violence that fills arroyos WIth torrents. HISTORY OF ARIZONA GOLD PLACER MINING SUMMARY The original discovery of placer gold in Ariz. ona probably was made by Indians long before the advent of y. rhIte men. As early as 1774, according to Elliot's History of Anzona ( 1884), plac~ rs of the Quijotoa district, about 70 miles west o~ : rUCSOl:, were bemg worked extensively by Padre Lopez, a C~ strhan pnest. In 18? 8, according to Hamilton, 4 placers w~ r~ . dIscovered on the GIla River, about 20 miles east of where It Joms the Colorado, by Col. Jacob Snively. About 1862, La Paz placers, ; near the Colorado River about 65 miles north of Yuma, were dIscovered by Capt. Pauline Weaver. The greatly increased prospecting that followed these discoveries soon resulted in finding of the Dome Rock, Plomosa, San Domingo, and Yavapai County gold gravels. The Greaterville placers became known in 1874, and by 1900 many additional discoveries were made in various parts of the State. Since the most important placer fields of Arizona were brought to light prior to 1875, the most active and prosp~ rous period . for mining them was from 1858 to about 1880. Durmg that pe~' lOd, prospecting in portions of the region was opposed by the IndIans. Before 1885 the cream of the placer gold had been harvested, largely by ~ rude methods of dry- washing, sluicing, rocking, and panning. In order to rework the gravels for . gold not rec? ve. red by early miners, various attempts at dredgmg, hydrauhckmg, and large- scale dry concentration have been made; most, but not all of these afforts have been unsuccessful. In general, the placer industry of Arizona during the last sixty years has been unsteady and has depended upon such factors as unemployment or depressions. EARLY PRODUCTION The total production of Arizona's pl3; cers is difficult to ~ stimate, because the major production was durmg . the early ! rontre~ days, when no records were kept, and many mmers carned theIr gold with them when they left the country. 16 17 The following table is based on conservative estimates which ARIZONA PLACER PRODUCTION, 1902- 50 ( Compiled from U. S. Mineral Resources and U. S. Minerals Yearbooks) for certain districts, may be too low. ' No. of Gold Silver Total ESTIMATED PRODUCTION OF PRINCIPAL ARIZONA GOLD Years mines Fine oz. Value Fine oz. Value value PLACERS PRIOR TO 1900 1902 497 $ 10,273 0 $ 0 $ 10,273 Estimated 1! 103 568 11,741 20 11 11,752 Field Source of 1904 815 16,846 ° 0 16,846 production estimate 1905 2,064 42,663 306 186 42,849 La Paz $ 2,000,000 J. Ross Browne/) 1906 1,959 40,493 274 186 40,679 Gila City 1907 2,172 44,895 365 241 45,136 500,000 J. B. Tenney6 1908 1,497 30,943 258 137 31,080 Laguna 1909 1,386 28,649 183 95 28,744 1910 1,257 25,982 167 90 26,072 Muggins 200,000 1911 42 1,144 23,641 154 82 23,723 1912 51 2,082 43,046 388 239 43,285 1913 36 1,485 30,691 270 163 30,854 Kofa 40,000 E. L. Jones, Jr., 1914 57 1,458 30,140 241 133 30,273 U. S. G. S. Bull. 620 1915 49 1,705 35,248 309 157 35,105 1916 23 691 14,281 171 113 14,394 Castle Dome 100,000 J. B. Tenney6 1917 32 833 17,214 227 187 17,401 1918 13 205 4,234 33 33 4,267 La Cholla 1919 15 227 4,694 36 40 4,734 Middle Camp } 1920 8 221 4,567 15 16 4,583 500,000 1921 37 606 12,524 90 90 12,614 Oro Fino 1922 33 580 11,981 113 113 12,094 Plomosa 1923 24 428 8,854 72 59 8,913 1924 9 152 3,139 27 18 3,157 Weaver } 1925 18 206 4,267 24 17 4,284 Rich Hill 2,000,000 J. B. Tenney6 1926 21 339 7,007 56 35 7,042 1927 15 303 6,257 43 24 6,281 1928 22 310 6,400 46 27 6,427 Lynx Creek W. Lindgren, 1929 22 273 5,652 42 22 5,674 1,000,000 1930 41 632 13,057 85 33 13,090 U. S. G. S. Bull. 782 1931 68 1,069 22,103 157 45 22,148 Hassayampa 1932 179 3,480 71,933 454 128 72,061 ) 1933 179 5,130 131,126 603 211 131,337 Big Bug 1934 867 6,982 244,030 1,038 671 244,701 Groom Creek 1,000,000 J. B. Tenney6 1935 1,197 5,157 180,495 832 598 181,093 Minnehaha 1936 787 6,488 227,066 890 689 227,755 1937 376 4,399 153,965 649 502 154,467 1938 329 4,985 174,475 628 406 174,881 Greaterville 700,000 J. B. Tenney6 1939 142 6,409 224,315 691 468 224,783 1940 276 6.241 218,435 1,108 788 219,223 Quijotoa 250,000 J. B. Tenney6 1941 184 11,931 417,585 2,205 1,568 419,153 1942 163 2,836 99,260 398 283 99,543 1943 19 319 11,165 14 10 11,175 PRODUCTION AFTER 1900 1944 17 242 8,470 90 64 8,534 1945 18 540 18,900 45 32 18,932 As shown in th~ following table, the output reported from Ari- 1946 33 398 13,930 62 50 13,980 1947 30 314 10,990 21 19 11,009 zona place~ s durmg 1902- 50 amounted to 94,560 ounces of gold 1948 39 838 29,330 136 123 29,453 together WIth 14,099 ounces of combined silver valued at $ 2830- 1949 32 565 19,775 63 57 19,832 956. Of this yalue, almost. three- fourths was p; oduced during th~ 1950 24 142 4,970 4,970 ~ en- year perIod, 1933~~ 2, m large part by mechanized operations 1902- 31 27,164 $ 561,482 4,172 $ 2,592 $ 564,074 III the Lynx Creek, BIg Bug, and Quartzsite areas. 1932- 50 67,396 $ 2,260,215 9,927 $ 6,667 $ 2,266,882 . For all of the producing counties except Santa Cruz Pima and 1902- 50 94,560 $ 2,821,697 14,099 $ 9,259 $ 2,830,956 PIllal, the ~) Utput in ounces of placer gold was c~ nside; ably greater durmg 1932- 49 than during 1902- 31. Production figures for 1951- 1959 are given in the Appendix, Page 120. 18 YUMA COUNTY DISTRICTS The noted gold- placer districts of Yuma County include the Gila City, Laguna, Muggins, Castle Dome, Kofa ( S. H.), Tank, Trigo, La Paz, Plomosa ( Plomosa, La Cholla, Middle Camp, Oro Fino), and Harquahala. Their general locations are indicated on Figure 1. Additional small production has been reported from the Fortuna, Sonora, Mohawk, and Ellsworth areas. The Yuma County districts are in one of the most arid portions of the Southwest, with but little water outside of the Colorado and dila rivers. The climate is uncomfortable for placer mining during summer, but very enjoyable in winter. According to the U. S. Weather Bureau, Quartzsite, which is near the Plomosa, La Paz, and Dome Rock placers at an elevation of 800 feet above sea level, has a mean annual rainfall of 6.53 inches, a mean annual temperature of 69.6 degrees, a maximum temperature of 119 degrees, and a minimum of 9 degrees above zero on record. Yuma, which is about 20 miles from the Laguna and Gila City placers at an elevation of 141 feet, has a mean annual rainfall of 3.13 inches, a mean annual temperature of 71.7 degrees, a maximum temperature of 118 degrees, and a minimum of 22 degrees above zero. PRODUCTION The yield from gold placers in Yuma County prior to 1900, as estimated on a previous page, was perhaps $ 3,340, OOq. The recorded output amounted to $ 140,200 for 1905- 31 and $ 341,143 for 1932- 49, or a total of $ 481,143 for 1905- 49. GILA CITY OR DOME PLACERS Situation and accessibility: The Gila City placers, at the northern end of the Gila Mountains, about twenty miles east of Yuma, have been worked over an east- west length of approximately 2 miles and a width of from l/ 4 to % mile. Gila City was about 11h miles west of the present site of Dome, near the mouth of Monitor Gulch. The Southern Pacific Railway and the old Yuma- Gila Bend road skirt the northern margin of this placer ground. History: The Gila City placers became well known in 1858. Hinton, 7 in 1878, recounted their early history as follows: Within three months of their discovery, over a thousand men were at work prospecting the gulches and canyons in this vicinity. The earth was turned inside out. Enterprising men hurried to the spot with barrels of whiskey and billiard tables. Jews came with ready- made clothing and fancy wares; traders crowded in with wagonloads of pork and beans. There was everything in Gila City within a few months but a church and a jail. The diggings continued rich for four years and have been continuously worked on a smaller scale up to the present time. FarishB states that Lieutenant Mowry found, in 1859, about 100 men and several families working the gravels at Gila City and saw more than $ 20 washed from eight shovelfuls of dirt. He was told that from $ 30 to $ 125 per day was recovered by each worker. Although the cream of their production was skimmed before 1865, these placers have been worked more or less e: rery year down to the present time, and all the known productIve gravel areas have been dug over at least once. So far, this gold has been commercially recoverable only by dry washing or by panning of dry- washer concentrates at the river. Many plans have been made for large- scale recovery of the gold, but few of them ever passed the experiment. al stage. One such enterprise, attempted in 1870, has been mentlOned by RaymondU as follows: " At Gila City a San Francisco company has during the last year erected works to pump water fro~ t~ e Gila up into a large reservoir on top of the highest foot- hIlls m order to work the placers of the vicinity by hydraulic power. They use a 9- inch pipe through which they pump the wat~ r." Numerous gold- saving machines, large and small, have been tned out here but most of them were of inadequate design. The remains of one ponderous screw- trommel device, brought here scores of years ago, are still visible. During part of 1931, G. H. Mears attempted small- scale. hydraulicking operations in Monitor Gulch. Water was obtamed from a shallow well near the railway and pumped through about % mile of small pipe. . During the cool portion of the 1932- 33 season, approxImately twenty- five men, mostly transients, were ~ onducti: r: g dry placer operations in the Gila City area. The dally earnmgs per man ranged from a few cents ul? to ~ enerally less ~ han $ 1. The production of the GIla CIty placers prlOr to 1900 h~ s been roughly estimated by J. B. TenneyG at $ 500,000, ~ ost of whICh v.: as made prior to 1865. Their annual output durmg the seventIes amounted to a few thousand dollars. u Their recorded yield for the period 1934- 49 was valued at $ i3,828. Topography: The Fortuna and Laguna topogl'aphic sheets, ~ ssued by the U. S. Geological Survey in 1929, in~ lude the q- Ila City placers. Opposite the northern end of the GIla Mountams, the Gila River bottom lands lie about 165 feet above sea level and are bordered on the south by a gently northward- sloping, dissected bench that rises abruptly from 35 to 300 feet higher. From this bench, which is from 1J4 to 1 mile wide, the main mass of the Gila Mountains rises steeply. Numerous canyon systems, originating in the mountains, have cut steep, northward- trending gulches, from 35 to 150 feet deep, in this b~ nch. . Local geology: Faulted against the schISt of the mam mountain mass is the series of probable Tertiary sedimentary rocks that constitute the bedrock of the bench and of the placer deposits. These beds consist of well- stratified, weakly consoli~ ate~, locally mud- cracked clay, marl, arkose, and sands~ one. The~ r color is pale gray, buff, light green, or red, and theIr textur~ IS generally fine grained, even to the very base of the mountams. This consistently fine- grained character indicates that they were deposited when no high mountains were very near, and the well- 20 developed, locally mud- cracked strata point to deposition in shallow water bodies of considerable size. More or less faulting and tilting are evident throughout this forplation. In the road and railway cuts about 21fz miles north of Blaisdell, the beds strike N. 80 degrees E. and dip 25 degrees SE. The age of the sediments is regarded as probably Tertiary, although they are not as thoroughly cemented as the Tertiary sediments east of Wellton. 3 After tilting, these beds were beveled to a pediment. Overlying this pediment and capping the smooth- topped spurs of the dissected bench is a mantle of gravel, up to 15 feet thick. This mantle extends across the fault that separates the Tertiary (?) sediments from the schist, and continues, as narrowing terraces, for some distance headward into the canyons of the main mountain mass. Most of the material in these gravels appears to represent outwash from the Gila Mountains, but part of it is residual from erosion of the Tertiary (?) beds. Bryana interprets the outwash as having been deposited when the Gila River bed stood about 75 feet above its present level. The age of the gravels is regarded at Quaternary. The gulches that dissect this terrace are floored by gravel, sand and silt that are partly of local origin but mostly have been swept down by flood- waters from the mountains. At the edge of the mountains this material contains subangular to rounded boulders as much as 2 feet in diameter, but, northward, it becomes progressively finer. Gold- bearing groavels: The Quaternary outwashed material constitutes the gold- bearing gravels of the Gila City placers, and the pediment carved on the underlying Tertiary (?) sediments forms their bedrock. Most of the gold was found at or near bedrock in gulches, but a considerable amount was recovered from benches. Practically all the gulches and benches from % mile east to 3 miles west of Dome carry some gold, but Monitor Gulch, 1% miles west of Dome, was the scene of the most active mining. Northward from a point not far south of the railway, the bedrock is reported to extend under the water table. Depths of more than 15 feet to bedrock have not appeared to be profitable for mining. The gold not yet mined from these gravels is distributed in rather spotty fashion. In 1926, Messrs. Neal and Morgan found an $ 88 nugget on one of the benches near Monitor Gulch. They found the gravel to run about 50 cents per cubic yard in a few cuts, but 10 cents or less in many places. The fineness of this gold was about $ 19 per ounce. Ill About half of the nuggets were larger than match heads, and a fourth of them were from $ 3 to $ 6 in value. Almost all of the gold particles were rough, and the $ 88 nugget contained some white quartz. Origin: The gold of the Gila City placers probably came from various gold- bearing quartz veins in the northern end of the Gila Mountains. As no high- grade veins have yet been found there, the negative conclusion that many pockety or smal~ low- grad. e. veins supplied the gold seems most reasonable. Durmg. deposltlOn. of the fine- grained Tertiary (?) sediments, the GIla Mountams probably were marked by low relief, slow erosion, and relatively deep rock decay. After each period of subsequent uplift, they suffered rapid erosion, and the weathered quartz vems of the decayed rocks readily parted with their gold. Floods in th~ young canyon systems swept this detritus northward. droppmg out the gold as the stream gradients lessened. Further milling of these gold- bearing gravels by repeated floods concentrated the gold along the bottom of the channels, on the clayey bedrock. LAGUNA PLACERS The Laguna or San Pablo Mountains, in ranges 21 and 22W., immediately north of the Gila River and the Gila Mountains, contain gold placers' in their southern, southeastern, and southwestern portions. The Laguna quadrangle sheet, issued by the U. S. Geological Survey in 1929, shows the local topography. . Production: The total output from the Laguna placers IS unknown. Their recorded production during 1930- 42 was valued at $ 20,103. McPhaul area: Considerable placer mining has been done along the southern margin of the Laguna Mountains, fr~ m near the Gila River to about 1% miles north of McPhaul Bridge. A little dry- washing is still carried on. Only scanty production records for this particular area are available. During some years, its yield was lumped with that of Gila City. These placers, which conform to the exposure of tilted, beveled, Tertiary (?) sediments that constitute their bedrock, occupy an area of approximately % square mile, limited on the north and east by the hard rocks of the Laguna Mountains, on the south by the Gila River bottom lands, and on the west by the high gravel capping of the range. The Tertiary (~) strata, wh? se gener~ l character has been described on a prevlOus page, strIke and dIp in various directions and have been displaced by reverse faults of northeasterly trend. Many southeastward- trending arroyos have dissected the area. Most evidences of placer mining activity are confined to inter- arroyo benches near the base of the overlying gravels, but some at lower elevations and also along arroyo bottoms are evident. Las Flores area: Las Flores district, in the southeastern portion of the Laguna Mountains and 11/ 4 miles north of the Gila River is near the head of an alluvium floored gulch, at an elevation of 300 to 400 feet above sea level. The erosion of several goldbearing quartz veins in this district has given rise to small placer deposits. . . .. According to Raymond, 9 placer mmmg was carned on m Las Flores area chiefly by Mexicans and Indians, at about the time when the Gila City placers were most active. Part of this placer 22 gold occurred in the vicinity of the Golden Queen and India claims, and some was followed downstream to the bank of the Gila River, A little placer mining has been done in several gulches along the southern margin of the mountains. No record or estimate of the amount of gold recovered is available. Laguna Dam area: At the eastern end of Laguna Dam, about ten miles northeast of Yuma, masses of black schist and coarse, granitic gneiss rise steeply for 250 feet above the Colorado River. Erosion of quartz veins in these rocks has given rise to coarse, rusty placer gold that, in places, extends into the bed of the Colorado River. In 1884 or 1885, an attempt was made to recover this river- channel gold by dredging, but a flood destroyed the dredge. In 1907, during the construction of Laguna Dam, placer nuggets and a small gold- quartz vein were found at the river margin of these mountains. Considerable prospecting has been done in several of the gulches of this area, and potholes, up to 100 feet above the river, were found to carry rather coarse gold. This coarseness points to a local origin rather than to long transportation by the Colorado River. The U. S. Mineral Resources report from the Laguna placers a production of $ 1,457 in 1910 and $ 1,989 in 1912. The potholes yielded most of this amount and have made some production since then. Similar, but most extensive, pothole placers occur on the California side of the Colorado River. During the cool portion of the 1932- 33 season, a maximum of fifty men were conducting dry- placer operations in the McPhaul and Las Flores areas. All of the ground was privately owned, but, in general, no royalties were charged. The average daily earnings per man were between 50 and 75 cents. At the same time, approximately twenty- five men were placering in the Laguna Dam area. MUGGINS PLACERS The Muggins Mountains, which occupy parts of Twps. 7 and 8 S" R. 18, 19, and 20 W" contain gold placers in their southern and central portions. These placers have been known for many years b~ t, be, cause of being less easily accessible than the neighboring GIla CIty area, they have not been so intensively worked. The Wellton, Fortuna, and Laguna quadrangle sheets, issued by the U, S, Geological Survey in 1929, show the topography of part of the Muggins Range. In the southern portion of the range, the major placers occur in Burro Canyon. Minor ones are found in smaller canyons in the vicinity of a prominent mountain that is variously known as Klotho, Coronation, or Muggins Peak, and also at the southern base of Long Mountain. Burro Canyon, which is accesible from Dome by some 10 miles of unimproved road, trends southward from Muggins Peak. Here, southward- dipping lava flows, intercalated with thick beds of conglomerate, form a rugged terrain, This conglomerate, which consists mainly of coarse, subangular pebbles of gneiss and granite, rather firmly cemented in a sandy to clayey matrix, forms the bedrock of the placers. The goldbearing gravels occur principally as ancient bars several feet above the stream channel and, to a less extent, i~ the. pre, sent stream bed, The gold occurs as particles up to 0.15 mch m dIameter, mostly concentrated at or near bedrock. It. appea. rs t~ have been derived by erosion of the conglomerate, m whIch It was probably present as low- grade placer material deriv: ed frOi? goldbearing quartz veins originally contained in the gneISS, schIst, and granite of the range. , ' Gold placers occur in the central portIOn of the Muggms Mountains in the vicinity of the headward forks of the long, northwest~ ard- trending canyon that bisects the ra~ ge. The grav. els of this canyon, which are reported to hav: e yIelded many nch pockets during the early days, are occaSIOnally worked ~ f~ er heavy rains. This gold probab~ y ac: umulated. from the, dIsmtegration of quartz veins contamed m the adJacent schIst and gneiss. ' f During the cool portion of the 1932- 33 se~ son,. a maXImum 0 approximately twenty- five n~ en were workmg m the southern Muggins placer area. The dally recovery per man was generally less than $ 1. Practically all the water used must be hauled from wells in the Gila Valley. During 1932, E. H. Rhodes, storekeeper at Dome, purchased $ 2,296 worth of gO, ld w~ ich came Pl~ rtly f: om the Muggins and partly from the GIla CIty placers. BeSIdes this amount an unknown quantity from these areas was marketed elsewher~. The recorded production during 1934- 42 was valued at $ 6,867. CASTLE DOME PLACERS The principal gold placers of the Castle Dome M~ untains are east and south of the Big Eye mine, which is 31 mIles by ro~ d northeast of Dome. The gold occurs mostly at or near bedrock m gulches and appears to have been derived from erosion of gold-bearing veins in the vicinity. .' These placers were discovered in 1884" but theIr productIOn to the end of 1907 is unknown. The U. S. Mmt report for 1~ 87 states that the field was being worked in a crude way by MeXIcan drywashers. According to data and esti~ ates compiled by J. B. Tenney, 6 their yield for the 1884- 99 penod would amount to between $ 75,000 and $ 100,000. During 1932- 33, seldom more than two or three men w~ re working in this placer field. Operations are hampered by scarCIty of water. . The recorded value of output was $ 10,247 for 1908- 25, and $ 29,589 for 1934- 44. KoF'A OR S. H. PLACERS A small area of gold placers in the Kofa or S. H. Mountains of central Yuma County, about 56 miles northeast of Yum. a,. ~ as been described by Jones. ll A geologic sketch map of the VIcIDlty 24 Figure 3.- Preliminary geologic reconnaissance map of the Kofa or S. H. placer area, after E. L. Jones, Jr., and N. H. Darton. is shown in Figure 3. Of these placers Jones says: The known placer deposits of the Kofa Mountains occur in a gulch draining westward north of the detached hills in which the King of Arizona mine is located. These placers have been worked for many years, and the production is reported to be about $ 40,000 in gold nuggets. At present ( 1914) the placers are being worked in a small way, and a yearly production of several hundred dollars is reported. The gold occurs in outwash deposits which consist of boulders and fragments from the metamorphic and volcanic rocks. The gold- bearing debris is said to be from a few feet to seventy feet deep over an area of approximately sixty acres. The gold is coarse and occurs near bedrock. It has evidently been derived from the disintegration of auriferous veins in the metamorphic rocks, as it is much coarser than that contained in the North Star and King of Arizona veins. ll During the winter and spring of 1932- 33, eight to ten men were working in the Kofa placer area. The average daily recovery per man. was 75 cents or less. Production of gold during 1935- 48, as credIted to the Kofa placers by the U. S. Minerals Yearbooks, was valued at $ 1,650. TANK MOUNTAINS PLACERS Some placer gold has been mined in the Tank Mountains at various times since the seventies, but no record of the production is available. Probably the earliest and most profitable activity was in the main gulch below the Johnnie or Engresser prospect, in the northwestern portion of the range. This placer gold presumably was derived from local gold- bearing veins. As the field was small its richer ground was soon worked out, but during the past sev~ ral years it occasionally produced a small amount of gold. Some fifty years ago, active dry- washing was carried on in shallow bench and stream gravels on the pediment near the Puzzles, Golden Harp, Ramey, and Regal prospects, at the eastern f{ lot of the range. The gold obtained from the Puzzles area is said to have been coarser than that from the other localities. 0,-,- l'-- L'... J'- J..__~~ Mile 5 ",,- KEY .............. 1 IOulwash fITTTTTJ rI1f I i ary lu. ll.. 1lJ andesile l7777:: l M( 110marphic tLLLLJ rock ~ Go/~- bearing L----. J v tI inS Recent production from these areas has been practically negligible. TRIGO PLACERS The Trigo placers are at the western' base of the Dome Rock Mountains, in T. 2 N., R, 21 W., approximately 22 miles by road from Quartzsite. The gold- bearing gravels occur in arroyo bottoms and in ancient bars and channels. Most of the gold is in the form of flat grains. For many years, small- scale, intermittent dry- washing operations have been carried on in this field, but no record of the total production exists. Operations are greatly hampered by the scarcity of water and the cemented character of the gravels. Their output during 1936- 49 was valued at $ 3.700. LA PAZ PLACERS Situation and accessibility: La Paz placers are south of the Colorado River Indian Reservation of west- central Yuma County, along the western foot of the Dome Rock Mountains, abOl~ t 9 miles west of Quartzsite and 6 miles east of the Colorado RIVer ( Figure 4). The district is accessible by some 5 miles. of unimproved road that branches northward from the QuartzsIte- Blythe highway. Topography: The Dome Rock Mountains rise steeply to , approximately 2,900 feet above sea level or more than 2,000 feet above the adjacent plains and are extensively dissected by deep canyons. From their western foot, a wide dissected bench slopes gently westward to low bluffs that limit the Colorado River bottom lands. No perennial streams flow through the placer district, but branching arroyos drain the run- off of rain:\:, seasons to the Colorado River. Water is hauled from QuartzSIte or from shallow wells near the river. A scanty supply is afforded by Gonzales Wells or by natural rock tanks, such as Goodman Tank. History: According to former State Historian Hall, l° the presence of placer gold near the Colorado River was learned from Indians soon after establishment of the military post at Yuma. These Indians gave a few small nuggets of gold to a trapper, Capt. Pauline Weaver, and about 1862, according to Browne, 5 guided Weaver and his party to the rich gravels. The party picked up about $ 8,000 in nuggets, returned to Yuma for supplies, and spread news of the discovery. Several hundred miners soon rushed to the district, found the placers to be very rich, and established the adobe town of La Paz about 2% miles from the river. This town, which soon attained a cosmopolitan population of over 1,500, became a station on the Overland ' I'rail from San Bernardino to Ft. Whipple and was the County seat until 1871,12 The district flourished until about 1864 when apparent exhaustion of the higher- grade placers and discoveries of new diggings caused a decline in activity. In 1873, 1874, and 1876, additions to the Colorado River Indian Reservation included much of the placer ground and greatly restricted mining. La Paz be- 27 26 o ,.. D. )- I '"'" [ J~ [ 3= a z ' w" ++ • a g I- ~ m :':"> " , 0 c a Vl t 0: ) )-'" "" z'' l' '-' ",'" ~~ ~ a oz q fa « ~~ o z?;:~ q'" c(~~ ~:..~ ~ 5 " c . J I-a. X w~ q I'" W I-came practically deserted, and the site of this once flourishing town is now marked only by adobe ruins. After the area was excluded from the Indian Reservation in 1910. New La Paz Gold Mining Company acquired control of a large portion of the placer ground and made preparations for large- scale hydraulic treatment of the gravels. Four shallow wells were drilled in the Colorado River flood plain some 4% miles west of the placers. Water was to be pumped from these wells through a 12- inch pipe line to a reservoir 540 feet above the river or 225 feet above the placers. Part of the pipe line was installed, but from 1912 to 1915 the land was again included in the Reservation, and the project was not completed. Several other plans for large- scale operations have been outlined, but none of them have been carried out. Production: Information on the earlier production of the La Paz placers is given by Browne,'; who quotes a letter from A. McKay, a member of the Territorial Legislature from La Paz, as follows: Of the yield of these placers, anything like an approximation to the average daily amount of what was takeJ; l out per man would only be guess work. Hundreds of dollars per day to the man was common, and now and again a thousand or more a day. Don Juan Ferra took one nugget from his claim that weighed forty- seven ounces and six dollars. Another party found a chispa weighing twenty- seven ounces. Many others found pieces of from one to two ounces up to twenty, and yet it is contended that the greater proportion of the larger nuggets were never shown.... It is the opinion of those most conversant with the first working of these placers that much of the greater proportion of the gold taken out was in nuggets weighing from one dollar up to the size mentioned above..... As has been said above, the gold was large and generally clear of foreign substances. .... All that was sold or taken here went for $ 16 to $ 17 an ounce. Since the year 1864 until the present, there have been at various times many men at work in these placers, numbering in the winter months hundreds, but in the summer months not exceeding 75 to 100; all seem to do sufficiently well not to be willing to worl< for the wages of the country, which are and have been for some time $ 30 to $ 65 per month and maintenance. No inconsiderable amount comes in from these placers now weekly, and only a few days ago 1 saw, myself, a nugget which weighed $ 40, clear and pure from foreign substance. . . . . Of the total amount of gold taken from these mines, 1 am at a loss to say what it has been.... 1 have failed to find any pioneer whose opinion is that less than $ 1,000,000 were taken from these diggings within the first year, and in all probability as much was taken out in following years. According to Hall, IO local gold nuggets and dust were the principal currency, particularly for gambling, in La Paz; but a large portion of the gold obtained by Mexican placer miners went to Mexico. On account of the crude methods of recovering the gold, entirely by dry washing in pans or wooden " bateas," only the coarser gold could be saved, and only extremely rich ground would be payable. Wet methods were out of the question, for, according to Jones, 14 water packed from La Paz to the placers brought $ 5 a gallon during the rush period. With the introduction of dry- washer machines in the late sixties, greater quantities of material could be handled and a greater percentage of 28 recovery effected, but by that time most of the richer ground had been worked over. During the winter of 1932- 33, from fifty to sixty men were reported to be conducting small- scale, individual dry- washing operations in La Paz district. The average daily recovery per man was from 50 to 75 cents. La Paz placers are credited with a gold output valued at $ 14,705 for 1934- 37 and $ 805 for 1942- 49. Their production for other recent years is not separately recorded. Local geology: The Dome Rock Mountains in this vicinity ( Figure 4) consist largely of metamorphic rocks and granite, of Mesozoic to early Tertiary age. For a short distance west of the foot of the range, these rocks floor a dissected pediment and constitute the bedrock of the principal placers. Westward they disappear beneath extensive deposits of sand, gravel, and clay which in turn are locally overlain by coarse outwash grav~ ls and boulders. Distrib~ tion. and character of the placer gravels: The placers oC, cur mamly m Goodman Arroyo a~ d Arroyo La Paz, and in trIbutary gulches such as Ferrar, GarcIa, and Ravenna. According to Jones, 13 Ferrar Gulch, tributary to Arroyo La Paz, contained the richest and most productive placers of the district. Evidences of former work are seen in the old excavations and, ... in exposures of bedrock where the wash was shallow.... The thickness of . the gold- bearing wash is variable, ranging from a few fe~ t on the mountam slopes to an unknown measure in Arroyo La Paz and m the gulch traversed by the ( old) Quartzsite- Ehrenberg road.. Shafts have bee~ ~ unk in the wash to depths of thirty feet without reachmg bedrock and It IS reported that in places the wash is at least sixty feet deep. By far the greater part of the auriferous material is unworked especially that in the lower courses of the arroyos where the wash i; deep, F'errar Gu~ ch for mo, st of its course has been p; actically worked out. The gold- bearIng materIal consists of sand and clay inclosing angular rock fragments of greatl~ variable size. Tests indicate that about twenty per cent of the wa~ h wIll pass through a quarter- inch screen, and tli'e largest ~ oulders weIgh several hundred pounds. The material near the s1! rface IS unassorted and is unconsolidated, being readily worked with pIck and shovel.. That at depths of fifteen or twenty feet is consolidated but t~ e cementmg substances readily disintegrate on exposure to air: DepOSIts of wash below the depths of test pits may prove to be similar to the outwash on the east slope of the Dome Rock Mountains and in the Plomosa placers, where the material is firmly cemented with calcium carbona~ e and requires crus1; lin~ in. order to free the gold. The ground stands suffiCIently well to permIt smkmg of shafts without use of timber The w~ sh is readily worked in dry- washer machines, the only requir~ ment bemg that the ground must be dry. The gold is said to be distributed throughout the wash, though in the early workings the richest yield was obtained near bedrock. No estimate could be made of the probable gold content of the wasli in the La Pa~ ~ istrict because of la~ k of detailed data and of uncertainty as to the lImIts of the wash, but In one area the deposit, said to contain values of 50 to 75 cents per yard and much of it thirty feet or more deep occupies at least 640 acres, and considerable areas extend into the small': er gulches. The size of the gold now recovered from the deposits of the La Paz. district probably averages only a few cents, but as' already stated the gord recovered from the early workings was much coarser. The gold' is rough ~ nd angular, an~ particles of iron cling to some of the nuggets. Magnetite IS ~ lw~ ys found In the concentrates, and boulders of magnetite, the largest welgh. Ing several pounds, are frequently found on the surface. HeIkes14 states that the largest nugget found in this region was valued at $ 1,150 and assayed about 870 in fineness. Most of the gold particles or nuggets ranged in value from 5 cents to $ 10, although $ 20 and $ 40 nuggets were not uncommon. La Paz placers were probably derived by the erosion of many gold- bearing veins in the Dome Rock Mountains. PLOMOSA DISTRICT The Plomosa placer district includes the eastern and western margins of La Posa Plain. This plain, which separates the Plomosa Mountains on the east from the Dome Rock Mountains on the west, is approximately ten miles wide and from 1,000 to 1,300 feet in elevation. It is dissected, particularly in the marginal portions, by many shallow arroyos tributary to its northwardflowing axial channel, Tyson Wash. These arroyos contain no water except for short periods after heavy rains. Most of the water used in the western part of the district is hauled from shallow wells at Quartzsite. Heikes14 states: " Surrounding the post office of Quartzsite, in the Plomosa mining district, and extending in every direction, covering an area of about 7,500 acres, is found dry- placer ground with values to an average depth of fifteen feet and varying from five to fifty feet. The gold content per cubic yard is reported to average in coarse gold from ten cents to several dollars." The most important placer fields in the Plomosa district are La Cholla, Oro Fino, and Middle Camp, which lie near the Dome Rock Mountains, and the Plomosa, near the Plomosa Mountains ( Figure 4). These areas have been worked intermittently by individual dry- washers since the early sixties. Several lP. rge- scale operations have been planned or attempted. The 1901- 31 value of production from the Plomosa placer district is given by the U. S. Mineral Resources as $ 44,826. During part of the winter of 1932- 33 more than 100 men were reported to be placer mining in this district. The recorded yield during 1934- 49 was valued at $ 176,042. LA CHOLLA PLACER AREA La Cholla placers comprise an area 4 or 5 miles long and of irregular width bordering the eastern foot of the Dome Rock Mountains south of the Quartzsite- Blythe Highway. Here, a gently eastward- sloping pediment or rock floor eroded largely on tilted bluish- gray slates, borders the mountains and extending beneath the gravels of the plain, constitutes the bed~ rock of the placers. The gravels in general consist of an unassorted aggregate of subangular to slightly rounded slate, schist, and quartzite fragments, more or less firmly cemented with lime carbonate. They I 30 are commonly of medium texture but range in size from fine material to boulders 3 or 4 feet in diameter. The gold occurs mostly at or near bedrock, but some is erratically distributed throughout the gravels. Its particles are characteristically angular and crystallized and range in diameter from that of a pin point up to liB inch or more. The gold has not been transported far and probably was derived from numerous small gold- bearing veins in the adjacent mountains. BInd: sand is abundant only in the shallower diggings. During the first half of 1933, the principal activity in La Cholla placers was on a group of three claims held by G. W. McMillen and Guy Hendrix. On part of this ground, at the eastern foot of a low, steep spur, many old pits, shallow shafts, and drifts proclaim earlier placer mining actiVity. A few hundred feet farther east, the operators sank a shaft tha, t struck bedrock at a depth of 84 feet, According to Mr. McMillen, lO a small pay streak was cut at a depth of 42 feet, and rather finely divided gold was found 15 feet above bedrock. At bedrock, the shaft encountered a rich southeastward- trending channel. When visited in June, 1933, this channel had been followed by some 300 feet of drifts and minor stopes, but its width and length had not been determined. As shown by these workings, the bedrock surface slopes about 15 degrees southeastward and forms natural riffles. The richest gold- bearing gravel occurs within a few inches of the bedrock and is particularly concentrated in the Vicinity of reefs and undulations on the bedrock surface, or where boulders are abundant. In places, it contains up to an ounce or more of gold per cubic yard. Locally, crevices in the bedrock contain placer gold for depths of 1% to 2 feet. Although openings in these cemented gravels required little or no timber, the material mined did not require crushing, It was run through a %- inch trommel screen and then conveyed to a bin from which it was passed over a two- tier dry- washer driven by a small gasoline engine. The tailings from this operation contained approximately 50 cents in golq per cubic yard. Production during the first half of 1933 amounted to about $ 6,000 in gold that ranged from 920 to 924 fine. Five men were employed. In June, 1933, the gravels in a secondary surface channel, a few hundred feet north of the shaft, were being mined with a power shovel. These gravels, reported to run 75 cents per cubic yard, were being treated experimentally in a wet jig for which water was hauled from a well 3% miles distant. Production figures for La Cholla placers are not available. According to the U. S. Minerals Yearbooks, La Posa Development Company during 1939 operated continuously in the area and handled 15,033 cubic yards of gravel; this project was suspended in early 1941. ORO FINO PLACER AREA The Oro Fino placers are at the eastern foot of the Dome Rock Mountains, in the Vicinity of the Quartzsite- Blythe highway. 31 Here, tiltEd,. beveled shl atI. e alndt~~ te n~~~ s~~~ t~~:~ fa~~~ c:~ n'ER~ gravels, WhlCh ar~ re a lVe y m much slaty materIals. t' I mined but During the early days, the~ e placer11 : e: e ~~ ~~~ h, iduals,' Ac- ~~ r~~~~ e~~ ~~~~~~[ J~ g ~~;~ s I~ it~~~ fr~~~ l~~ r~ ps~~~ l~~~~ ~:~~~ ! ina Gold Mmmg ~ m~ a~ y t W From these samples it was found sunk every few hun re ee. f ents to ' over $ 1 per that the gold content ranged from a :~ cThe colors ran from cubic yard and aver~ ged ~ 8 cen~ s ~~~ ~ he gold was of about $ 19 less than 1 cent to 2 cen s, eac, $ 20 67 er ounce). Here the per ounc~ fineness, ( laluat~ of~ a~ f u~ con; olidated rock debris, ~~ l~:~~ r:~! t ili~~~~ I: ndc~~~~ rlYingcemented gravel 18 or more feet thick. MIDDLE CAMP PLACER AREA The Middle Ca~ p placer area, I, U:~ Oed~' etsetlybynoarthmiolef twhiedeOraot Fino, is 4 or 5 mIles long from ea~ Mountains Here according theCehastehrn14fo" oRticohf tsheeamDsom0 fegRraovcel on bedrock yield' f. romthfour ttoo tenurtI~ m, es the vaIue 0 f th'ICker 1g0ratve$ ls25a" nd in creVIces ere halvl- eurbinegen1f9o3u2, ndtwnougcgoemtspawm? erstha$ ttempOted iarge- scale operations in this tract. d f M'ddle Camp Placer Gold, Inc., La On ground lease rom I. ed ut a large machine equipped Cholla Mining Compal ! 1y, L~ d., yl p; roximately 100 feet of sluice with a 3lh- yard drag me s ove, a r cover This machine, for boxes, and settlinghtanlksd which wa: er was au e ff~~: aQte~ ar~ zsite, y; perated for only a few we~ ks. I C r oration installed a plant equipped Amencan ~ oarhse G1d d ~ Po Cottrell tables. It was operated, with a draglme s ave an w . f b t two weeks. with water hauled from, Qu~\ t; s~~~ n~;~ n~~ viduals were carryingInonJusnme, all1- 9s3c3a, leapdprryo- xwlmasha. meg m. the Middle Camp placers. PLOMOSA PLACER AREA d f La Posa Plain and the western Placers at the eas~ rn ~ ~ e 0 bout 5 miles southeast of Quartz-foot of the Plomosa oun aIns,. a bl old in the early sixties, site ( Figure 4), pro~~ c:~ oc~~: I~ er: va~ atle. Bancroft, lG in 19~ 9, but no record ? f t f h nd had been honeycombed WIth found that portIOns 0 t e grou b made to work these small tunnels. Various attempts h~ vean~ e~ et methods. Considplacers on a la. rge scalbe, both bi t y erable productIOn has een ma e yindividual, small- scale dry-washing. t ' h' h east of the district are about The Plomosa Moun ams, w IC b e the plain consist 2la0r0g0elfyeeot faSbCoh~ Iest, segaralmeyteel, aonr dl~~~ e; e~~ l~ a~~ rocIes. Th~ schist, 32 which contains gold- bearing quartz veins and stringers, was probably. the original source of the placer gold. Accordmg to Bancroft, the placer gravels, which occur in old drainage ch. annels leading away from the southwestern part of the mountams, are made up of fragments of schist, granite, and quartz, cemented by lime carbonate. This conglomerate or " cement rock" ~ anges in thickness from a few inches up to many feet, dependmg largely on the shape and size of the former channels, arid rests upon grayish- green, schistose bedrock. Regarding the placers, HeikesJ. i quotes extracts from a professional report by John A. Church as follows: In some localities pits have been sunk to a depth of twenty thirty and fifty feet or. more to be9s of cement which are richer than the gravel. Near the mounta~ n the gol~ IS coarser, but the gravel is much less. Miles of the great depOSit, extendmg westward from the mountains and from three to fo~ r miles in width, have been cut into by deep ravines, and they afford ~ I1es of banks ten to fifteen feet high in which the upper layer of gravel IS well exposed. From these banks, as far as investigations could be made, saIJ; lples gave an average return value of 64 cents per cubic yard with gold estunated at $ 18 an ounce.... There were no failures. The results lay between the extremes of 42 cents and $ 1.04 per cubic yard. The limit of the gr~ v~ l act. ually explored was 2,400 by 1,500 feet and eight yards deep.... Wlthm thIS area bedrock was not reached at any time. During. the winter of 1932- 33, approximately twelve men were engaged m small- scale dry- washing operations on the Plomosa placers. Average daily earnings per man were from 25 to 50 cents. Production dUring 1942- 49 Was reported to be valued at $ 5,740. HARQUAHALA PLACERS The late L. C. Shattuck, of Bisbee, stated lO that, in 1886 and 1887, he worked a small placer in Harquahala Gulch which is in the southwestern portion of the Harquahala Mount~ ins 8 miles south of Salome. For a short while, Mr. Shattuck and hi~ partner e~ ch recovered abou~ an ounc. e of ~ old per day. Although long ~ mce w? rked (: mt, t~ I~ ~ lacer IS of mterest because of occurring m the Il? medlate VICI! 1Ity of the rich Harquahala or Bonanza lode, whIch was not dIscovered until 1888. MOHAVE COUNTY DISTRICTS AND PRODUCTION In Mohave County, gold placers have been worked in the Chemehuevis, Silver Creek, Lewis, Lookout, Wright Creek Willow Beach, Gold Basin, and King ' Tut ( Lost Basin) areas. The most productive of these have been the King Tut Gold Basin and Chemehuevis. " The recorded yield from gold placers in the County was valued at $ 3,442 for 1909- 31; $ 52,446 for 1932- 49; and a total of $ 55,888 for 1909- 49. CHEMEHUEVIS PLACERS The Chemehuevis placers of southwestern Mohave County are in the foothills of the Chemehuevis or Mohave Mountains, about 18 miles southeast of Topock. This area is part of the Gold Wing mining district. Its climate is relatively dry throughout the year and hot during summer. In general, the gravels are angular and free from large boulders. Where deep, they are cemented with lime carbonate. The gold is fairly coarse. During the winter of 1932- 33, a maximum of thirty men were working at one time in the placers of the Chemehuevis Mountains, but most of them left with the advent of hot weather. According to the late J. H. Jones, lO formerly of Topock, their gold production amounted to about $ 1,200. A little activity was reported in Dutch and Printer's gulches, on the northeastern side of the range. The Chemehuevis placers have been worked intermittently by small- scale dry methods fot many years. Probably the most activity has been in the Mexican or Spanish diggings, in the vicinity of the Red Hills, at the southwestern foot of the range. The recorded production of placer gold from the district during 1934- 43 was valued at $ 7,111; it came largely from the Chief claim. SILVER CREEK PLACERS Some minor gold placers occur in the valley of Silver Creek, about 6 miles by road downstream from U. S. Highway 66 and 5 miles northwest of Oatman. lIere, an irregular pediment of volcanic rocks is overlain by a mantle of gravels which locally contain a little placer gold. During the winter of 1932- 33, Gold Gulch Gravel Company attempted to work this ground with a large centrifugal bowl machine for which water waS piped several miles. A short run, however, sufficed to determine that the gold present was insufficient to make the project profitable. A short distance farther southeast, a little small- scale placer mining, chiefly sluicing in connection with assessment work, has been carried on. According to B. White, lO one of the operators, the gravels there are very firmly cemented with caliche and contain about 100 pounds of black sand per cubic yard. This gold is about 730 in fineness. LEWIS PLACER The Lewis placer is on patented property of the old Bi- Metal gold mine, 3 miles southwest of Kingman and % mile northeast of McConnico. Here, a granite area about 300 feet in diame. ter has been considerably mineralized with slightly auriferous pyrite. Regarding the Bi- Metal deposit, Schrader10 says: The free gold to which the deposits owe their value seems to have been derived from a considerable thickness of overlying mineralized rock. As this overlying rock became disintegrated and was removed by erosion, the fine gold liberated from it gradually worked into the underlying rocks in which it is now found. Below or outside of the oxidized zone of mechanical concentration probably only very low- grade ore occurs. In 34 ~~~:~~;~~ e~ l~~~~~~ t: ti of dr b ainftage j within or at the border of the area, t bi on y ow ng water has taken place several ~ n~ i~: n~~ u~ f:~ rly ~ o: re gold, of which some of the largest nuggets been panned. a a 0 ar each in gold value, are reported to have During the winter of 1932- 33, Al Lewis mined and sluiced the gravels from 17 a sma~ l draw in. this area. According to E. Ross Householder, of Kmgman, thIS material ranged in value from $ 1 to $ 5 per cubic yard and yielded about $ 900 in gold that was worth $ 20.21 per ounce. LOOKOUT PLACERS The Lookout placers are in the Maynard mining district near the northern ~ nd of the Hualapai Mountains, about 6' miles ~~ iit~ deast of Kmgman. Here, certain areas of shallow gulch and 1 SI ~ 7gravels contain rough, wiry placer gold. E. Ross House- $ holder states that one dry- washer in this area obtained about 150 worth of gold during the 1932- 33 season. WRIGHT CREEK PLACERS Sm~ ll gold plac~ rs occur in the upper reaches and tributaries C1. jirl1: ht Cre~ k, In the northeastern portion of the Cottonwood I s. ntermIttent, small- scale operations have been carried on here for the past decade, but the total production has been small. COLORADO RIVER PLACERS thThe sands and gravels of the Colorado River, downstream from e. mouth of the qrand Canyon, contain finely divided gold whIch several dredgmg and sluicing operations have attempted to ? flover: .? ne of these enterpr~ ses is mentioned by Heikes18 as 0 thWA . The l~ rge dredge bUIlt in 1909 on Colorado River near e ~ Izona sIde, opposite EI Dorado Canyon Nevada wa~ of. the suctIOn type .... It was built to work the ~ and bar~ and faIle. d on firs~ test to extract the fine gold. It was subse uentl car: Ied from ItS moorings by high water and wrecked duJrig th~ sprmg of 1910." River- bar placers: Minor amounts of coarse gold have been ~ ecovefred by small- scale operations in elevated bars that have een or? 1ed largely by tributary canyons. At WIllow B. each, 65 miles from Kingman and near the Hoover Da~ hIghway, one of these ancient bars contains the ~ andY HarrIs placer. This bar covers an area of about 250 square eet, near the . outer bow of a curve in the Colorado River and rbsts upon an Irregula~ surface of gneissic granite some 150 feet bo~ rd the strealm. 1 d t IS made up of an unassorted aggregate of ers, gr~ ve , an. sand. The boulders, which range u to mo~~ than SIX feet m diameter, are but slightly rounded Pand cou not h; av~ been transported far. Likewise the coar of the gold mdIcates a local derivation. This pla~ er materi: i:~ pro~ a~ yb eroded fro~ gold- bearing rocks in the Vicinity and was e, y way of trIbutary gulches, to the river where it ac-cumulated in the outer portion of the nearest c » rve. Subsequent downcutting of the river has left this bar elevated in its present position. Some thirty- five years ago, Mr. Harris worked this placer by tunneling on bedrock. In 1920, an unsuccessful attempt was made to sluice the gravels with water pumped from the river. A lessee took out about ten ounces of gold during 1931. Black sand is abundant in this placer. Some medium coarse placer gol< l has been recovered from a bench near the Colorado River about 21h miles north of Pyramid Rock. GOLD BASIN PLACERS Situation: The Gold Basin Placers of northwestern Mohave County are in T. 28 and 29 N., R. 17 and 18 W., about 9 miles south of the Colorado River. Their central portion is accessible by about 9 miles of unimproved road that branches northward from the Kingman- Chloride- Pierce Ferry highway at the northern end of Red Lake playa, 56 miles from Kingman. History: The first known discovery of placer gold within this area was made in May, 1932, by W. E. Dunlop. In August of that year, approximately 100 men were testing the field with dry- washers. Most of them left during the winter rainy season, but about forty were there in June, 1933. As most of these people were transients who took part of their gold elsewhere, any approximate estimate of the production is difficult to reach. Experienced, industrious workers each made $ 1 or more per day, but most of the operators averaged less than that amount. Drywashing here is interrupted during rainy seasons. During the summer of 1933, a large- scale dry- treatment plant ( Plate I) was installed by S. C. Searles in Sec. 29, T. 29 N., R. 18 W. This plant, equipped with grizzley, trommel, screens, and a battery of twelve dry- washers, had a rated capacity of 20 cubic yards of gravel per hour. The U. S. Minerals Yearbooks credit the Gold Basin placers during 1934- 49 with a gold production valued at $ 14,500. Topography and geology: Gold Basin is floored largely by a detrital fan that slopes eastward from the White Hills to Hualapai Wash. This fan is approximately 6 miles long from west to east by 5 miles in maximum width. Its vegetation consists principally of small desert shrubs and abundant Yucca or Joshua trees. Water for all purposes is hauled chiefly from Patterson Well, several miles away. The gold- bearing gravels occur principally in arroyos and gulches, between elevations of 3,300 and 2,900 feet above sea level. They consist mainly of medium- grained, angular schist and gneiss fragments together with a minor amount of finely divided quartz. A small proportion of boulders, generally less than 2 feet in diameter, is present. The placer gravels are mostly from 1 to 3 feet thick and rest upon a bedrock of firmly cemented gravels. Their gold occurs partly as flour gold and partly as angular fragments that range from 5 cents to $ 3.50 in 36 37 value. Some of the gold is attached to black schist particles. Black sand is rather abundant. The tests that have been made of this ground show that the gold is erratically distributed. Certain pockety channels contain thin streaks that run more than $ 1 per cubic yard, but most of the arroyo banks probably contain less than $ 1 per cubic yard. The cemented gravels of the bedrock are reported to carry a little gold, but no test of them has been made. Origin: The White Hills, which are made up of granitic, schistose, and volcanic rocks, contain many argentiferous and auriferous quartz veins. 16 Erosion of such veins doubtless gave rise to the Gold Basin placers. The occurrence of most of the gold as angular fragments, some of which are attached to black schist particles, indicates some such nearby source. KING TUT PLACERS Situation: The King Tut placers of northwestern Mohave County are in T. 29 and 30 N., R. 17 W., about 8 miles from the Colorado River. They are accessible from Kingman, via Chloride and the Pierce Ferry Highway, by 72 miles of improved road. History: So far as is known, the first discovery of placer gold within this area was made in February, 1931, by W. E. Dunlop. According to Charles Duncan, l° the gold production prior to June, 1933, was incidental to sampling and amounted to about $ 700. All of this land was privately owned, chiefly by the Duncan ranch and by the Santa Fe Railway. On the Robeson and Joy lease, in sec. 14, T. 30 N., R. 17 E., a Cottrell dry concentrator with a capacity of 25 tons of gravel per hour was being installed. During 1934- 42, a gold production valued at $ 23,510 was credited to the Lost Basin ( King Tut) placer area. Topography and geology: Here, a gravel- floored plain, from 3,000 to 4,000 feet above sea level, rises southwestward between Grapevine Wash and the base of a low northward- trending ridge locally called the Lost Basin Range. Near these mountains, the plain is a pediment floored with schist and granite. Its vegetation consists principally of small desert shrubs and abundant Yucca or Joshua trees. Water for all purposes is hauled from Patterson Well, 5 miles distant. The richer gold- bearing gravels, as known in June, 1933, occur within an area some 8 miles long by an undetermined width and are confiined mainly to the arroyo- bottoms. They consist predominantly of slabby schist pebbles, with few boulders more than 10 inches in diameter, intermingled with abundant silt and sand. These deposits are generally less than 2 feet thick and rest upon caliche- cemented gravels. Their gold occurs partly as fine material and partly as flat, rugged nuggets that are known to range up to 1/ 16 ounce in weight. Black sand is abundantly associated with it. Northeastward, the gold particles and the gravels become progressively finer grained. 36 Tests of part of the field showed average values of 69 cents per cubic yard. In Most of the testing was done with dry- washers. A few small wet machines were tried, but the water for them WaS found to be too costly. According to M~. Duncan, lO the underlying cemented gravels are also gold- bearmg, but no comprehensive test of them has been made. . Origin: The King Tut placers probably originated from eroSIOn of a group of gold- bearing quartz veins in the Lost Basin Range. The ragg~ dn~ ss of the gold nuggets, many of which carry attached quartz, m( hcates a local derivation. Plate n.- Sampling operations in King Tut placers, 1960. YAVAPAI COUNTY INTRODUCTION Yavapa. i County includes a region of approximately 8,150 square mIles.. Exc~ pt fa: th~ edge of the plateau along its northeastern margm, thIS regIOn IS characterized by north- northwestward- trending mountain ranges and valleys. The largest of these ra. nges, the Br~ dshaw, is approximately 45 miles long by 20 miles ~ lde, ~ nd att~ ms a maximum altitude of 7,971 feet. The region IS dramed. chl~ fly by the Verde, Agua Fria, Hassayampa, and Santa Mafla flvers, of which the lower courses are 1600- 2200 feet above sea level. In general the h~ gher ridges and valieys ~ re w. ell wooded and watered, while the slopes below 5,000 feet m altItude . tet; d to be brushy, and the country below 3,500 feet favors semIafld types of vegetation. 39 Placers have been worked in more than thirty districts or areas of Yavapai County. As the boundaries of these distri. cts are not clearly defined or limited, there has been some confUSIOn regarding the designation of local areas among the statistics reported in the U. S. Mineral Resources Volumes and U. S. Minerals Yearbooks. Descriptions in this bulletin include the more important districts as well as some of the minor ones for which information has been obtained. EARLY HISTORY Discoveries of gold in Yavapai County were announced by two expeditions during 1862- 63. One of them, guided by Pauline Weaver and including Major A. H. Peeples, located the Rich Hill placers, while the other party, headed by Capt. Joseph R. Walker, found placer and lode gold deposits in the Lynx Creek, Hassayampa, Big Bug, Groom Creek, and Granite Creek areas. Some fifteen or twenty years earlier both Weaver and Walker had trapped extensively in Arizona and probably had become aware of areas favorable for prospecting. On May 10, 1863, the Walker party organized the Pioneer placer mining district to include " certain portions of Oolkilsipava River and its tributaries." 2o A month later it was extended to the " Francisco ( Verde) River on the east, to the divide of the river Aziamp ( Hassayampa) and Antelope Creek on the west, and to include the Agua Fria River and its tributaries." 21 Each placer claim was to be 300 feet long by 150 feet wide. Prescott, originally a settlement chiefly of placer miners, became the Territorial capital in 1864. . PRODUCTION The value of production from Yavapai County gold placers prior to 1900 is conservatively estimated at $ 4,000,000. After 1929, interest in these placers was greatly stimulated by the financial depression; owing largely to mechanized methods and also to numerous small- scale operations, their value of output rose to $ 379,800 for the year 1941. It receded during World War II and for 1949 was $ 15,505. The recorded yield of gold from placers in Yavapai County amounted to $ 241,510 for 1905- 31 and $ 1,701,728 for 1932- 49, or a total of $ 1,943,238 for 1905- 49. LYNX CREEK PLACERS Physical features: The Lynx Creek placers are in central Yavapai County, along Lynx Creek from near Walker, 7 miles southeast of Prescott, to its junction with Agua Fria Creek, 13 miles east of Prescott. Lynx Creek, which flows northward between foothill ridges of the Bradshaw Mountains, and northeast and eastward through conglomerate terraces of Lonesome Valley, has an approximate length of 18 miles. Since it extends between elevations of about 40 .... .... .. cg ell U I. HH H 41 7,000 and 4,600 feet above sea level and drains a large, high region, it receives a considerable amount of water each season and is perennial in its upper, pine- wooded course. At Prescott, which is about 5 miles west of the creek at an elevation of 5,320 feet above sea level, the normal annual fall of rain and snow water is 18.52 inches, the highest temperature recorded was 105 degrees, and the lowest 12 degrees below zero. 22 Early history and production: According to former State Historian Hall, lo the Lynx Creek placers were discovered in 1863 by a party of California miners headed by Capt. Joe Walker. As the news of their discovery filtered back to California, the number of placer miners on Lynx Creek increased to 200 or more. Active work, with hand rockers, pans, and small sluices, continued along the stream fOT several years before exhaustion of the richest gravels. Like most placers of the Southwest, unfortunately, no records of the early- day yield are available, but Lynx Creek is noted as ope of the most productive gold- bearing streams in Arizona. Raymond9 reported its 1874 production at $ 10,000, and Hamilton4 estimated the total prior to 1881 at $ 1,000,000. According to A. C. Gilmore, lO of Prescott, about 100 men were working the Lynx Creek placers prior to 1885, and some of them recovered about $ 20 per day. W. R. Shananfelt, 1° of Prescott, stated that one man recovered $ 3,600 in eleven days from the lower reaches of the creek. Dredging operations: In the late eighties, B. T. Barlow- Massick built a small dam above the present Prescott- Dewey highway bridge, installed a few miles of 30- inch pipe, and did some hydraulicking, but a flood destroyed the dam. About 1900, the Speck Company tried out an old dredge a short distance below the bridge, but the roughness of the bedrock there prevented its success. Later, G. S. Fitzmaurice operated this dredge farther down the creek, but, after recovering about $ 800 worth of gold, the dredge fell apart. A large patented gold- saving machine was tried out nearby at about this time, but also without success. In 1927, Lynx Creek Mining Company attempted large- scale operations with a moveable plant consisting of an Insley excavator, a Barber Green stacker, screens, and sluices. During 1932 a California- type dredge ( Plate II.) was installed in the lower Lynx Creek placer area, on the G. S. Fitzmaurice property, below the dam illustrated in Plate III. The dredge was 50 feet long by 35 feet wide by three stories high and had a capacity of 100 cubic yards per hour. It drew 30 inches of water and normally required about 85 gallons of new water per cubic yard of gravel treated. Approximately twenty men were employed to conduct the operation three shifts per day. Calari Dredging Company operated this dredge during MarchJuly, 1933, and in sixty- one days treated 60,000 cubic yards of gravel which yielded approximately 32 cents per cubic yard. In June of that year, the dredging was being carried on to an ap- 42 proxi~ ate depth of 6 feet. The gravel, as mined with a 1l, 2- yard draghne shovel, was. passed through a lO- inch grizzly, then through a trommel wlth a 5- 16- inch screen, whence the oversize went to a stacker, and the undersize into a sluice equipped with 400 square feet of angle- bar riffles. I Of the total gold in the gravels, from 85 to 90 per cent was ~ xtr~ cted. It ranged in size from flour up to fragments 0.1 inch m dlameter and was accompanied by abundant black magnetic sand. Subsequent dredging operations in the Lynx Creek area may be summarized as follows: Arizona Dredging and Power Company, latter part of 1933. L~ n~ Cree~ Placer Mine Company, 1934- 40. With large floatmg washmg plant and two draglines, treated 556,115 cubic yards of gravel in 1938 and 542,815 cubic yards in 1939. Was largest producer of placer gold in Arizona Phoenix Lynx Creek Placers Company, 1934: Rock Castle Placer Mines Company, fast quarter of 1939. Handled about 12,000 cubic yards of bench gravel by means of a dr: y- Iand. dredge equipped with four bowl- amalgamators. Placer KlI~ g Mmes, Inc., in September 1940 took over property and equlpment of Lynx Creek Placer Mine Company Big Bug Dredging Company 1941. . Minona Mining Company, 1948- 49. Other dredges at one or two properties, 1940- 42. . Small- scale op~ l" 8tions: Intermittent small- scale placer minmg ~ as been ca~ rled . on in the Lynx Creek area for many years, parbcularly durmg bmes of depression. In the spring and summ~ r of 1933, for example, approximately thirty men were recoverm~ gold. by rocking and sluicing there. Most of the gravel was obtamed m small dry. side- gulches and packed to water. In places, trees were bein~ unrooted in order to reach pay dirt beneath them. A short dlstance below the Dewey highway bridge one man : was drifting on old side- gulch channels. ' Accordmg to A. S. Konselman, lO of Prescott, who kept accurate reco~ ds of the gold produced by these operators, the average earnmgs per man amounted to 50 cents per day. Production since 1900: The total value of production from the Lynx Creek placers, including the Walker area, since 1900 ~ as b~ en on the or~ er of $ 1,000,000. For the period 1914- 31, as hsted l? the U. S. Mmer~ l Resources, it was $ 27,373. For 1933- 49, accordmg to the. U. S. Mmerals Yearbooks, it amounted to $ 903, 604, most of wh~ ch was recovered prior to 1942. Geology: In lt~ south~ rn or uI? per reaches Lynx Creek flows across. pre- Cambnan schlst, gramte, and other intrusive rocks. In the. northeastern portions of the area these older rocks are overlam by conglomerate of medium- grained, fairly well- rounded gravels, firmly cemented in sand and volcanic ash. This conglomerate, which constitutes the bedrock of the placers of lower Lynx Creek, appears to be overlain on the west by late Tertiary basalt of Bald Hill. The youngest formation consists of gravel, sand, and boulders that occupy the bed and flood plain of Lynx Creek. This material, which contains the placer gold, is generally well- rounded except in the upper reaches of the stream. From near Walker to a point about 8 miles in air 1ine downstream, or 2 miles below the Dewey highway bridge, the placers occur as thin relatively narrow benches or bars. Downstream from that point, in the bottom of the steep- walled gulch formed in the conglomerate fill of Lonesome Valley, the placers attain a maximum width of over 1; 8 mile and a thickness of 8 to 24 feet. Although some gold is present throughout this thickness, the richest material commonly is at the conglomerate bedrock and in a streak 4 feet thick about 2 feet above the bedrock. Lindgren23 states that the average value is reported at 18 cents per cubic yard. " At Walker the placers yielded nuggets worth as much as $ 80, at about $ 16 an ounce. Lower Lynx Creek produced a finer- grained gold of higher value, worth about $ 18 an ounce. Such an enrichment in the value of the gold is common and indicates a solution of the silver by the waters." The gold of lower Lynx Creek ranges from finely divided material up to $ 6-$ 8 nuggets, and is associated with considerable hematitic and magnetitic black sand. The placer gold of Lynx Creek apparently was derived from disintegration of numerous gold- bearing quartz veins contained in the pre- Cambrian rocks of the Walker area. WEAVER AND RICH HILL PLACERS Physical features: The Weaver and Rich Hill placers are in southern Yavapai County, a short distance northwest of Octave and 6 to 8 miles east of Congress Junction. This placer area is at the southern margin of the Weaver Mountains, which rise to more than 5,000 feet above sea level or more than 2,000 feet above the adjacent desert plain on the south. Rich Hill attains an elevation of 5,200 feet above sea level between the deeply eroded canyons of Antelope Creek on the west and Weaver Creek on the east. Since the higher portions of the Weaver Mountains receive at least 18 inches of rainfall per year, these two south- flowing creeks often have some water in their upper courses and are subject to torrential floods during rainy seasons. History and production: In the early sixties a party consisting of Capt. Pauline Weaver, Maj. A. H. Peeples, and others, happened to camp at the base of Rich Hill, after their guide had deserted them on the desert north of Wickenburg. A Mexican of the party, while looking for their strayed animals, discovered loose gold nuggets on top o'f Rich Hill. This discovery led also to the finding of placers on Weaver and Antelope creeks. This whole area soon became the scene of intense activity, and in five years, according to Hall, lO produced about $ 500,000. The loose gold underneath boulders and in crevices of rocks on Rich Hill was easily gathered, but more effort was required to work 44 I the ~ ouldery gravels of Weaver and Antelope creeks by panning, ! rockmg, and sluicing. As much as $ 40,000 is said to have been taken from a certain acre, and the production of the whole area prior to 1883 was estimated by HaJl1ilton4 at $ 1,000,000. The town of Weaver, on Weaver Creek, flourished until about 1896 but is now marked only by crumbling ruins.. Blake, in 1899, stated that the score or so of men who were working these placers from year to year were supposed to be recovering over $ 2.000 per month. The value of known output from the Weaver and Rich Hill : placers since 1900 has been approximately $ 150,000, of which $ 83,975 was recorded for the years 1905- 31, and $ 62,049 for 1934- 49. According to the late Carl G. Barth, Jr., 10 the yield for the year prior to June, 1933, was valued at about $ 1,800. Approximately fifty men were carrying on sluicing and rocking in this field during the winter of 1932- 33, but their. number decreased to eighteen with the advent of summer. Because the gravels are mostly coarse ( Plate IV) and have been repeatedly worked, the average daily earnings were not more than 30 cents per man. Minor amounts of dry- washing have been carried on in the vicinity of Oro Fino Gulch, in the · southernportion of the area. In~ 938 th~ chief producer was Universal Placer Mining C? rporation, whIch operated a power . shovel and dry- concentratmg plant at the Thunderbird property. Geology: The Weaver Mountains are made up mainly of old granite and schist, overlain in places by younger sediments and lava. These mountains contain the Congress, Fool's Gulch, Octave, Yarnell, and numerous smaller gold- bearing veins. The placer ground covers an area of approximately 8 by 5 miles. According to local people, the most productive portions were in the northern half of this area and included about 10 acres on top of Rich Hill; portions of the sides of Rich Hill; channels and benches of Weaver, Antelope, and other washes; and gravel benches that lie between these washes. ~ ich Hill, which rises steeply for about 2,000 feet above the plam, consists of : ather ~ ntensely jointed granite. In places, it IS traversed by thm, lentIcular quartz veins which carry pyrite, galena, and gold. The top of this mountain is a hilly mesa about ~ 8 mile long by % mile wide, that evidently represents ~ n ero~ lOnal remnant of the elevated Weaver Mountain pediment. It Includes several acr~ s of broad, shallow b. asins and drainage channels whose gramte floors are mantled WIth granite boulders and very thin, rusty, sandy soil. A few angular pebbles of quartz and of hematite are locally present. The once- abundant occurrence of placer gold within the shallow basins and drainage channels is proclaimed by numerous old workings that scoured every square foot of their surface. ( See Plate V.) Along washes and benches below Rich Hill, the placer material consists of iron- stained gravel and sand, up to 10 or more feet Plate IV.- Typical gravels of Weaver Creek placers. thick, together with abundant subangular boulders that are 2 to 6 feet in diameter ( Plate IV). Character' of the gold: According to Heikes, 14 the fineness of the Rich Hill and Weaver placer gold is 910. On Rich Hill, according to Blake, 24 one nugget worth $ 450, and three worth a total of $ 1,008. were found. C. B. Hosford, l° of Octave, stated that the largest nugget found on upper Weaver Creek was worth $ 396, and that two chunks of quartz contained $ 450. In the spring of 1931, a large nugget was brought into the office of the Arizona Bureau of Mines from the Weaver region. This nugget was described by Heinerhan25 as follows: The nugget is in general outline shaped somewhat like a human molar. It measures approximately 53 mm. across the widest portion of the ' roots,' and 47 rom. from the bottom of the ' root' to ' the crown.' Several fragments of slightly iron- stained quartz remain in the center of the mass. The total weight is 270.90 grams, and it may be calculated that the nugget consists of 252.38 grams of metal and 18.52 grams of quartz ... worth $ 152.62 in gold and 22.71 grams of silver worth 21 cents at date of writing. During the 1932- 33 season, a few nuggets ranging up to more than 3 ounces each in weight were obtained from Weaver Creek. Two nuggets, each weighing more than 5 ounces, were found on upper Antelope Creek. Away from the margin of the mountains, coarse gold becomes progressively more rare. 46 Plate V.- Top of Rich Hill in 1933. Origin: These placers probably were derived by erosion of many small veins within the vicinity and concentrated by local streams. Such large, angular boulders ( Plate IV) and such generally coarse gold could not have been transported far in ancient river channels. COPPER BASIN PLACERS Gener~ l features: The Copper Basin placers are north of Copper BaSIn Wash, between Skull Valley and the Sierra Prieta. They are accessible from the Santa Fe Railway at Skull Valley and Kirkland by a few miles of road. Here, a plain slopes southwestward from an elevation of 5,500 feet at the base of the Sierra Prieta to 4,000 feet at the junction of Skull yalley and. Copper Basin Washes. Most of this plain is ~ oored WIth extenSIve deposits of gravel, sand, and clay, locally mterbedded and mantled with volcanic tuffs and flows, but its easternmost 1 to 3 miles of width is a pediment that has been carved on granite. The whole area is dissected by many southwestward- trending gulches which are tributary to Skull Valley Wash. Part of Copper Basin Wash carries a small flow of water throughout the year, but the other gulches are dry except for occasional short periods. The bedrock of the placers generally consists of cemented gravels, but, in certain areas relatively far from the mountains it is hard clay. ' The gold- bearing gravels are made up largely of granitic sand together with various amounts of boulders and clay. Near the mounhlins. thp. houldp. rs are rp. lativelv abund: mt and coarse but. 47 in the western part of the area, they are mostly less than one foot in diameter and constitute a small percentage of the gravels.. The clay content is erratically distributed, but tends to be relatively greater towards the western part of the area, except near Copper Basin Wash where sand predominates. The gold- bearing gravels form a relatively thin mantle on the ridges, but range in thickness from 3 or 4 feet up to 15 or mo~ e feet in the gulches. They contain some gold throughout theIr thickness but generally are richest in a thin streak at or near bedrock. Widely distributed tests indicate that much. of the ground within this field contains from 50 to 83 cents 111 gold per cubic yard. . The gold, which is from 925 to 950 fine, occurs as particles th~ t range in size from small specks up to nuggets several ounces m weight. In the western part of the field, nuggets worth more than 25 cents each are rare. Near the mountains, the gold fragments are characteristically wiry to angular and coarse. Associated with the gold is abundant mag: t; e~ itic black sa~ d. In the upper portion of Copper Basin Wash, OXIdIzed copper mmeraIs are commonly present. Throu~ hout the southwestern portion of the field, small particles of cmnabar ( mer~ ury sulphIde) and natural amalgam, which were doubtless . derIved from the cinnabar veins of Copper Basin, are apparent m the placer concentrates. Erosion of gold- bearing veins of the Sierra Prieta, partic~ larly in the pediment area, provided the gold of the Copper Basm placers. The increase in angularity and coarseness of the gold towards the mountains indicates a local derivation. History and production: The Copper Basin pla~ ers, which had been intermittently worked in a small way pnor to 1929, began to attract renewed interest with the advent of the depression. During 1932, three concerns carried on large- scale operations in the Copper Basin placers. In the southwestern part of the field, the ~ orback and E~ ston and Smith companies ran separate concent~ atmgplants, equIpped with power shovels, trommels, screen, DIester- type tables and amalgamators, which had capacities of 350 or more yards per eight hours. Water for these plants was pumped from shallow wells and re- used as much as possible. The Forback & Easton plant closed down in the fall of 1932, and was taken over by R Cassendyke. Its production is reported to have been from $ i2 000 to $ 15 000 worth of gold, most of which was in particles wo~ th less th~ n 25 cents each. The Smith Company was succeeded by Gold Star Placer Company, ~ lso contr? lled. by Mr. Cassendyke. Its plant, which was resummg operatIOns m June, 1933, is illustrated in Plate VI. During April and May, 1932, a lessee operated a Ph- yard power shovel and a Girand. barrel concentrator on ground in Mexican Gulch, about 2lh mIles from Skull Valley. According 48 to Mr. Lyda, l° he recovered approximately $ 5,000 worth of gold. Some $ 15 nuggets were found, but most of the gold ranged from $ 3 nuggets down to particles as small as a mustard seed. In June, 1933, Operators and Developers Company had installed in the northeastern part of Copper Basin a plant with a rated capacity of 500 cubic yards per twenty- four hours. This plant was equipped with a vibrating grizzly, washing trommel, vibrating screens, sluice boxes, and Wilfley and Diester- type tables. Water was to be pumped from the Lorna Prieta mine shaft, about 1 mile farther south. The placer gravel was to be mined from an adjacent gulch. During the year prior to June, 1933, from fifty to sixty smallscale, individual operators recovered gold mainly with rockers ( Plate XI) and small sluices in Copper Basin Wash. According to A. S. Konselman, 10 of Prescott, the daily earnings per man ranged from 25 cents to $ 1 and averaged about 50 cents. The U. S. Minerals Resources credit the Copper Basin placers with a production valued at $ 1,023 for the year 1931. The yield for the year prior to June, 1933, as estimated by G. L. Lyda, lO of Kirkland, amounted to about $ 31,000, of which $ 26,000 came from large- scale operations. The output for 1949, as reported in the U. S. Minerals Yearbooks, was valued at $ 27,972. Thus the total production for 1931- 49 was on the order of $ 60,000. BIG BUG PLACERS Physical features: The Big Bug district is in south- central Yavapai County, in the general vicinity of Big Bug Creek, Mayer, Poland, McCabe, and Humboldt. This region includes a pediment at the northeastern foot of the Bradshaw Mountains and extends up local gulches. Big Bug Creek generally has water in approximately the upper half of its course. History and production: Gold was discovered within the Big Bug district in the late sixties, but the greatest activity in placer mining there was during the eighties of the past century. Considerable sluicing, rocking, and panning have. gone on, especially in upper Big Bug Creek as far down as Mayer, and in Chaparral and other gulches near McCabe. Dry- washing has been done to some extent in drier portions of the region. No estimates of the early production are available. In 1926, bullion having a fineness of 0.952 was recovered by sluicing operations of the Uncle Dudley Mining Company. Large- scale operations were attempted during 1932 by Humphries Investment Company of Denver, with a large trackmounted power shovel, a Barber Green stacker, and sluices. In July, 1933, Pantle Brothers began large- scale operations on a 220- acre tract leased from Messrs. Shank and Savoy, west of Big Bug Creek and about 3 miles northwest of Mayer. In August, 1933 they were minipg old placer and mill tailings in a gulch near Big Bug Creek; this material was bouldery to sandy, with but little clay, and rested upon cemented gravels. The gold oc-i' 50 curred as rather irregularly distributed, flat to round and ragged particles which ranged up to about 50 cents each in value. Pantle Brothers' concentrating plant was equipped with four rubber- riffled Ainlay centrifugal bowls ( Plate VII). Fed with a one- yard power shovel, it had a capacity of 1 cubic yard per minute and required about 300 gallons of water per minute. Ample water for this plant was obtained at bedrock. Production during the first forty days of run amounted to about 45 ounces of gold. Four men were employed. Approximately 9,000 cubic yards of gravel were handled during 1933, and the gold produced in 1934 amounted to more than $ 15,000. Subsequent operations in the Big Bug area, as reported in the U. S. Minerals Yearbooks, have been as follows: In 1938 a washing plant equipped with four Ainlay bowls worked at Hill group. Hassayampa River Mining Comp~ ny ran a dragline dredge at Lawson group but suspended operations late in the year. In 1939 dry- land dredging was carried on at the Savoy and Shanks properties, and sluicing was done at the Hill, Johnson, and Caywood properties. During 1940 a dry- land dredge and a ' dragline dredge each worked a few months at the Shanks and Savoy property. Big Bug Dredging Company operated a 2%- yard dragline dredge at the Hill property the last four months of the year and recovered 1,100 ounces of gold. In 1941 Arical Mines, Inc., worked a dragline floating dredge at the Star or Lawson property. Big Bug Dredging Company continued to operate at the Hill property until in March when it ~ oved to the Lynx Creek area. A dragline dredge operated at the Nelson and Fitch property in 1946. Some sluicing was carried on in the district during 1943- 49. Small- scale operations were particularly active during 1932- 33 when, according to the late F. W. Giroux, 1° sixty or more men were placer mining within the area, largely in the gravel benches and side gulches of Big Bug Creek, several miles northwest of Mayer. In this area, which had been rather intensively worked during the past, most of the mining was done by tunnels from which the gravel was packed to sluices, rockers, or small powerdriven concentrating machines. Efforts were handicapped by the large proportion of coarse boulders within the gravels. The recorded gold production from the Big Bug placers amounted to $ 30,751 for 1910- 31 and $ 462,480 for 1934- 39, or a total of $ 493,231 for 1910- 49. Geology: The principal rocks of the Big Bug district are preCambrian schists, smaller amounts of granite and granodiorite, abundant rhyolite dikes, and Tertiary basalt flows. The placers occur in stream channels and on intervening mesas of a roughly triangular area that extends for about 20 miles east and northeast from the head of Big Bug Creek. The gold of the stream placers is generally coarse. One of the largest nuggets found in the Big Bug' region contained about $ 500 worth of gold figured at $ 20.67 per fine ounce. In the gravel mesa between Humboldt and Mayer, the gold, which is rather finely divided and associated with considerable clay, amounts to about thirty to forty cents per cubic yard. Presumably, quartz veins within older rocks of the vicinity provided gold for the stream placers, but the finely divided gold of the gravel mesas between Mayer and Humboldt may have undergone longer transportation. HASSAYAMPA PLACERS Introduction: Placer gold occurs along much of the Hassayampa drainage system in Yavapai County. This creek rises in the Bradshaw Mountains at an elevation of approximately 7,000 feet above sea level, a few miles south of Prescott, and crosses the Yavapai- Maricopa County line two miles north of Wickenburg at an elevation of about 2,000 feet. Owing to its large drainage area, the main creek carries torrential floods in rainy seasons and abundant subsurface water during dry months. History: According to local reports, the greatest period of activity in the Hassayampa placers was from 1885 to 1890. The failure of Walnut Grove Dam in 1880 prevented large~ scale operations that had been planned for a tract downstream from Wagoner. Small- scale, individual sluicing and rocking have been carried on every year, but the total production therefrom is unknown. During the 1932- 33 season, more than fifty men were working the Hassayampa placers of Yavapai County. Most of this activity was confined to the side gulches. In general, the average daily returns amounted to about 50 cents per man. A dragline dredge worked intermittently on the Hobbs property during 1940- 42 and 1946. Production from the Hassayampa placers, as listed by the U. S. Mineral Resources and U. S. Minerals Yearbooks, amounted to $ 3,659 for 1926- 31 and $ 61,568 for 1934- 49. In addition, the Black Rock area was credited with an output valued at $ 2,776, the Blue Tank area with $ 1,609, and the Wagoner area with $ 1,008, during 1934- 49. Geology: The principal rocks of the lower Hassayampa area of Yavapai County are pre- Cambrian granite and schist, mantled in many places by Tertiary gravels and lavas. The upper portion consists of pre- Cambrian schist and granite, intruded by smaller masses of diorite, granodiorite, and rhyolite porphyry. PreCambrian to Tertiary quartz veins within the schist and granite provided the gold that erosion has concentrated in the placer deposits. The gold found along the upper reaches of the creek was generally coarse, but downstream it was progressively finer. GROOM CREEK PLACERS The Groom Creek placers are in south- central Yavapai County along Groom Creek, from 4 to 6 miles south of Prescott. This 54 creek heads in the Bradshaw Mountains west of Walker at an elevation of more than 5,000 feet above sea level and joins Hassayampa Creek at a point about 5 miles in air line farther southwest and 1,900 feet lower. These placers were discovered in the sixties and were actively worked during the eighties. Their total production prior to 1930, according to former State Historian Hall, lO probably has amounted to about $ 100,000. During the past several years, only slight activity has been reported in the Groom Creek placer field, and only small amounts of gold have been produced there. Quartz veins contained within the local pre- Cambrian schist, which has" been intruded by diorite, granodiorite, granite and dikes of rhyolite porphyry, were the original source of the gold of these placers. WALNUT GROVE PLACERS The Walnut Grove placer district, south of Kirkland Junction, includes portions of the Placerita, French, Cherry, Blind Indian, and Mill drainage areas. Throughout a large part of this vicinity, the gulches have dissected a northeastward- sloping pediment of general elevation less than 5,000 feet above sea level. This pediment consists of granite, diorite, and steeply dipping schist, locally mantled by gravel and lava. It contains many small gold- bearing quartz veins. Erosion of such veins probably furnished the gold of the placers. No estimates or records of the early production of this field are available. In 1899, Blake24 stated that " The placers . . . at Placerita have long been known and worked, and are regarded as good- wages mines." According to the late A. B. Colwell, I° a dredging project was attempted several years ago on a small area of ground in French Gulch about 1 mile below Zonia. When water was available during the 1932- 33 season, approximately twenty- five men were placer mining in the vicinity of the junction of French and Placerita gulches, chiefly with rockers and sluices. Their average daily earnings were about 50 cents per man. According to A. R. Evans, l° of Kirkland, the production of this area for the year prior to June, 1933, amounted to approximately $ 2,000. This gold was fairly coarse, with many $ 5 and $ 10 nuggets and one $ 80 nugget. It was worth about $ 18 per ounce at the old price of gold. At the same time, in the upper portion and side gulches of Placerita Creek, three or four men were operating long toms and dry- washers on shallow gravels. They each obtained from 25 to 50 cents worth of coarse gold daily. Large- scale operations were started in June, 1933, on the Maude Lee claims, at the junction of Placerita and French gulches, The plant included a one- yard gasoline shovel, angle- iron riffles, and a barrel amalgamator. Here, the gravels consist mainly of granitic sand with some medium- coarse, flat schist boulders. A small flow of water occurred at bedrock. The Walnut Grove placer areas were credited during 1934- 36 with a gold production valued at $ 9,339. MINNEHAHA PLACERS Placer gold occurs along Minnehaha Creek, about 25 miles in air line south of Prescott, below elevations of 5,000 feet above sea level. Lindgren23 says: Minnehaha Flat is a northward- trending, well. tim~ ered and. watere~ basin on the headwaters of Minnehaha Creek: ~ hlCh dlScha~ ges m~ ~ a~ sayampa River near Walnut Grove, Placer mmmg was earned on ele l~ the eighties of the last century all the way up from the ' Old Log House to the Button Mine, also in branches coming in from the east. ~ he gold was worth about $ 17 an ounce and was extracted by arrastres, ~ IUlces, and dry- washers. The probable production was $ 100,000, accordmg. t? Mr. M. A. McKay, an old- time resident of the district. The fOld is belle\' ed to have been derived from the Fortuna lode near Lapham s place. Placers on Oak Creek, below Fenton's ranch, yielded gold valued at $ 924 during 1935- 40. MODEL PLACERS The Model placers comprise a small area in the vic~ nity of Model Creek on the western side of Peeples Valley. ThIS locality is accessible by some 2 or 3 miles of road whi. ch branches westward from U. S. Highway 89 at a gate % mIle north of Peeples Valley store. These placers have been known for m~ ny years, since the discovery of the M~ del a~ d othe: ~ old- bearmg veins in this vicinity, but comparatIvely ~ Itt1e mmmg of them has been done during the present generatIOn. , Here a granite pediment extends, from elevatIons of 5,000 to 4 500 feet above sea level between the eastern foot of the Wea'ver Mountains and Peeples Valley. This pediment has b~ en dissected to shallow depths by several small eastward- trendmg streams which carry water during only part of. the ye8: r: In pl~ ces between these gulches, it is co? cealed by thm gramtIc detrItus and soil which supports a thIck growth of brush and scrub oaPk. lacer gold occurs in Model and other gulches for some d." IS-tance upstream but the principal gold- bearing gravels bemg worked in June: 1933, occurred in small, local. basins or ch~ nnels on the pediment for a width of about % mIle on each SIde of Model Creek downstream from Pawley's property. . The placer' gravels, which consist mainly of granitic sand ~ Ith some clay and few boulders, are generally less than ~ feet t~ lCk. They contain a little gold throughout, but a~ e richest m a streak 6 to 12 inches thick that rests upon gramte or cemented granitic sand. Partial tests of this pay streak s~ owed about $ 1 in gold per cubic yard. The gold occurs as faIrly rough particles that range up to about lh ounce in weight and are reported to be about 850 fine. It was probably derived by erosion of goldbearing quartz veins in the vicinity. 56 In June, 1933, approximately twelve men were engaged in small- scale placer mining operations in this field. After stripping off the overburden, the pay streak was carefully hand- shoveled and swept from the bedrock and hauled to Model Creek for hand coneentration. BLACK CANYON PLACERS Placer gold occurs along Black Canyon, which upstream branches into Turkey, Poland, Bumblebee, and several other ? reeks and southward drains into the Agua Fria River. Accordmg to Lindgren, 28 Placers have been worked at several places in Black Canyon, particularly belo\~ the. Howard Copper Company's property. A few years ago a Portugese IS saId to have taken out $ 20,000 near the old stone cabin, one mile bel~ w Howard. There are also small placer deposits near Turkey Creek s~ tion, and every year more or less dry washing is done by Mexicans in thIS locality. The placer gravels in much of this field contain abundant coarse boulders. The gold particles are generally flat and fairly coarse. Black sand occurs abundantly in the gravels and adheres to the smaller gold particles. During the cool por~ ion of the 1932- 33 season, about twentyfi,: e . me~, mostly transIents, were engaged in small- scale placer mmmg m Black Canyon, chiefly between Arrastre Creek and Cleator, and to a small extent in American and Mexican gulches. Most of the concentrating was done with rockers and sluices and only a small amount with dry- washers. The average daily returns were very s~ all. W. J. Martin, storekeeper at Bumblebee, purchased approxImately $ 80 worth of gold per month and estimated IO that an equal amount was marketed elsewhere. The largest nugget found during that time came from American Gulch and was valued at $ 14.38. . On a bar some 3 miles south of Bumblebee, a plant equipped WIth a power shovel, screens, and tables was operated for a short time during the summer of 1932. Recorded gold production from the Black Canyon placers during 1934- 49 amounted to $ 12,758. GRANITE CREEK PLACERS Placer gold occurs along the upper branches and main course of Granite Creek, which rises a few miles south of, and flows northwar |