Stone in Arizona: an economic study

              S T O N E I N A R I Z O N A
An Economic Study
prepared for
ARIZONA DEVELOPMENT BOARD
by
Roland C. Townsend
Consulting Geologist
Phoenix, Arizona
THE ARIZONA DEVELOPMENT BOARD
1521 West Jefferson Street Phoenix, Arizona
PIERRE BAFFERT
Chairman
Santa Cruz County
ARLO WOOLERY
Cochise County
W. D. JAMES Coconino
County
EDWIN D. SMITH
Gila County
J. GREEN
Graham County
C. C. RILEY
Greenlee County
DAVID R. MURDOCK
Maricopa County
BERNARD M. MERGEN
Director
M. E. HAFLEY
Mohave County
ROYALL SMITH
Navajo County
HAROLD A. PATTEN
Pima County
PAUL LOUCKS
Pinal County
LEONARD SEXTON
Yavapai County
HENRY F. COLMAN
Yuma County
HARVEY PLATT
Apache County
CONTENTS
Page
Acknowledgments • 4
II Introduction --- 5
III General 6
A History 6
B Present uses 7
C Industry economic status ............... 7
D Exploration 7
E Production and values . 8
IV Resources • 9
A Sandstone 9
1. Geology and areal extent, Coconino sandstone 9
2. Structure • 10
3. Composition and physical character 10
4. Production 11
5. Shipping - 14
6. Costs 14
7. Specifications, products, trends in use 14
8. Problems 15
9. Moenkopi formation 16
10. DeChelly sandstone - - - - - - - - - - - - - - - - - - - - - - - - - - - --
-• - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
16
B Marble - 16
1. Geology and areal extent 16
2. Composition and physical character 20
3. Production, products, shipping, and costs 21
4. Specifications and trends 23
5. Problems ...... .....- 23
C Tuff - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ....................
................................................
25
1. Terminology and general geology 25
2. Character of representative deposits 28
3. Production ... 29
4. Problems 29
D Granite .--- .-. 31
E Slate ....--- 32
F Limestone - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 33
G Schist ...... ...._. 34
H Miscellaneous stone - - - - - - - - - - - - - - - - - - - - - - - - - - 34
1. Rhyolite and porphyry 34
2. Basalt and scoria . .--- 35
3. Travertine, tufa, and onyx marble 36
4. Quartzite and quartz 37
5. Jasper - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 38
6. Copper stained rock - - - - - - - - - - - - - - - - - - - - - - - ._...--•
..-..
38
7. Magnesite 38
8. Serpentine - - - - - - - - - - - - - - - - - - - - - - - - .. 38
4
CONTENTS
Page
V Available Stone — Land Status and Acquisition of Mining Rights - - - - - - 38
VI Transportation and Freight Rates .......................................................................40
A Railroads - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - . - 41
B Trucking - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 41
VII Labor Market - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 42
VIII Depletion Allowance, Taxes, and Insurance ......................................................... 42
IX Potential - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
X Glossary - - - - - - - - - - - - - ...... - - - - - - - - - - - - - - - - - - - - - .....-... - ... - 46
XI Annotated Bibliography - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 48
XII Agencies Concerned With Stone Industry .............................................................. 50
Map—Showing quarry sites and major transportation routes
I. ACKNOWLEDGMENTS
In preparing this report, many quarry operators and stone producers were con-tacted.
Not a single one refused aid or data; each has contributed information about
his experience in the stone industry, making the report possible. Use of specific data
is noted in the report. In addition, several state and federal agencies made avail-able
both time and information. Mr. Louis Smith and others on the staff of the Arizona
Department of Mineral Resources provided valuable data on quarry locations and
production. Mr. H. Wesley Peirce of the Arizona Bureau of Mines gave many
valuable suggestions. Mr. Frederick C. Ryan of the Arizona State Land Department
provided helpful data. Mr. Dee E. Reese and Miss Wilma Richard of the Arizona State
Employment Service gave helpful data on the labor market. Also, in-formation on
transportation was given freely by Mr. Hans M. Kruesl, Watson Bros. Transportation
Co., Inc., Mr. Donald B. Malcolm, The Atchison, Topeka & Santa Fe Ry. Co., and Mr.
C. F. Head, Southern Pacific Company.
5
I I INTRODUCTION
The natural beauty of rock formations in Arizona is famed the world around. No
wonder, then, that with the tremendous population growth in the west, stone pro-ducers
and users are looking to Arizona for sources to supply the ever-increasing mar-ket.
All of the principle types of building stone, and many unique varieties are avail-able
within this one state.
The purpose of this report is to draw together known data on occurrences of
stone, present production techniques and problems, types and varieties of available
stone, markets, labor and land conditions, and the general potential of the stone in-dustry
in Arizona. Thus, the report is primarily an economic study. Data on building
stone, landscaping stone, and crushed rock used in building for its decorative purpose
are included; aggregate, ballast, rip rap, etc. are not included. Compilation of com-plete
data on as widespread and varied an industry as this would probably be im-practical
at this time. Therefore, an annotated bibliography has been included; ref-erence
numbers in the text indicate items in the bibliography. Reference is also made
to the state and federal agencies that can provide additional data. It is hoped that this
report is sufficiently detailed to show basic trends, economics, and potential to both
the present producers and those considering participation in this industry.
Data have been gathered from many sources. A map is included showing by
symbol the general location of many active and inactive quarries, as well as unworked
prospects known to have a good potential. Over the years some stone deposits have
been worked intermittently by various persons; an absolute count and check of re-ported
locations has been unfeasable for this report. In some places several quarries
are located within an area that must be represented by only a single symbol. Under
such circumstances, omissions or errors in location are both unintentional and un-avoidable.
6
I I I GENERAL
HISTORY comprehension, compounding building needs.
Stone is doubtless the world's earliest and old- Third, new equipment became available, from
est building material, prized through the ages for power machines in quarries to guillotine cutters
its strength and durability, for its adaptability to in stone yards, to high speed, economical trucks
both simple and sophisticated construction needs, on new highways. At the same time, cross-country
and for its decorative qualities. Trends in use have freight rates climbed, hampering shipping to the
been determined by accessibility and local needs, west from traditional stone sources in the east.
transportation, changing construction and stone While these factors may diminish somewhat, their
production methods, and by current fashions. Ari- continuing effect at a steady rate will tend to sta-zona
stone has been used since the earliest settle- bilize the stone industry.
ment of the state. Until 1946, commercial produc- Immediateley after the war, building needs
tion was intermittent, with local projects and use were simple, and were met with available mate-being
dominant. Quarries were opened for tempo- rials. As the construction gap began to close, new
rary markets or individual jobs, then virtually building techniques, materials and styles made
abandoned. stone popular. Aluminum and glass enjoyed novel
After World War II, several new factors con- uses, and steel in concrete changed structural re-tributed
simultaneously to the development of the quirements. By themselves they are efficient, but
Arizona stone industry. First, a building boom they tend to give a hard, cold appearance. Natural
necessarily followed the war. Second, population stone was found to give texture and warmth to
in west coast areas and in Arizona increased beyond structures. So the age-old concept of stone used
Section of field stone in a wall of cast slabs with exposed aggregate.
7
primarily structurally, changed to use of stone as a
facing or curtain wall, and use in places where its
decorative qualities are paramount but durability,
strength, and low maintenance are also desired.
In addition, use of uncut and of crushed stone
increased. New building methods now allow for low
pitched roofs with crushed stone coatings, and highly
decorative and efficient uses of terrazo have become
popular. Style changes have introduced exposed
aggregate, again combining the structural factors
with decorative qualities. Fashions in landscaping
have sent prospectors to the hills for sources of
flagstone, rubble, and crushed rock for walks,
driveways, and gardens. Fines from crushing
operations are being used in cast products.
One of the most important style trends has been
to design almost any uncut stone into large wall
areas. Even otherwise nondescript stones, that might
as individual pieces lack attractiveness, such as field
stone, talus, or slabby boulders, may be used with
attractive results. The only requirement seems to be a
common color or texture, such that the whole effect
is that of a large mass. This mass effect, combined
with modern materials such as aluminum and glass
gives an appearance of both dignity and stability
found only in older buildings made wholly of stone.
Few new business buildings in the Phoenix area lack
a mass effect stone wall. Another trend opening new
design possibilities has been to different mortar
joints; some are recessed, others abnormally wide.
Some stones are cast into poured walls, giving the
stone an appearance of floating. In all, keeping
abreast of design trends has become an important
phase of the stone industry.
PRESENT USES
Today the uses of Arizona stone are many and
varied,15 but they can be grouped as follows:
1. Buildings — structural and decorative
dimension and uncut
2. Roofing -- granular, crushed rock, insulation
3. Terrazo — granules, aggregate
4. Inside flooring — sheets of stone
5. Retaining and yardwall — cut and uncut
6. Patios and walks — flagstone and crushed
rocks
7. Furniture -- table tops, benches
8. Monuments
9. Fireplaces and fireboxes
10. Landscaping — ground cover, uncut and
crushed
11. Landscaping — planters, edging
12. Fines — aggregate, swimming pool copings
and plaster
INDUSTRY ECONOMIC STATUS
Basically, growth of the stone industry is de-pendent
on the construction industry, and in turn, on
population growth. The full potential of the state's
resources, and the most fficient production are
realized when a stable m rket of a size able to
warrant substantial capita investment is attained.
Although new uses of stone, wider range of products,
and vigorous sales promotion can in-crease demand,
long-term stability requires a large population within
the optimum marketing area.
Obviously, before the end of World War II,
Arizona alone could not suppoit a large stone in-dustry
similar to those in the eastern United States.
Even west coast markets were nbt easily developed.
Today, however, factors mentioned above appear to
provide a basis for a strong stone industry. Here-tofore,
producers might be said to have "felt their
way" in expanding their part of the production.
Today, market demands sometimes exceed supply,
and stone materials usually available in Arizona are
even imported. Today, producers are looking to
mechanization and otherwise increasing production,
and to assuming processing functions now being
done elsewhere.
EXPLORATION
After being prospected for, more than a cen-tury,
Arizona would seem to have no geologic se-crets.
Indeed, most of its surface has been trod by
explorers, prospectors, miners, and geologists. Also,
inasmuch as nearly all rock formations can yield
some material to meet basic construction require-ments,
the need for exploration for stone quarries
would seem small. However, the character of rock
formations may vary greatly froth place to place,2
and quality and style specifications require in-creasingly
greater selectivity of quarry sites. In order
for a producer to compete for markets, he must
consider such things as accessibility, transportation,
labor supply, and housing conditions in the
8
choice of a quarry site. Moreover, the success of a
quarry may depend on geologic changes or variations
in the stone not apparent except by close
examination; a marble quarry may run into a fault or
shear zone, or a good "dune set" of beds in sandstone
may be truncated by a younger set. Many abandoned
quarries are testimony to the need for careful
selection of sites.
In a recent publication, L. W. Currier 7 has given
detailed procedure for the broad, geologic exploration
for quarry sites, and also describes the industrial
factors in evaluation of deposits, with particular
reference to traditional producing areas in the eastern
United States. He points out that the lower production
from the far western states is not a measure of
availability of suitable deposits, but is due to factors
of population, economic conditions, and industrial
development. These factors, plus the facts that
western deposits are more complex in distribution,8
and market demands are for new construction forms
and new colors and textures, make exploration
requirements somewhat different in Arizona.
It should also be noted that for stone production
in Arizona, the character of most rock formations at
any significant depth is not known. That is, no
quarries have been developed to depths far be-low the
weathered zone, or into `fresh' rock that is not
affected by surface considerations of topography,
chemical alteration, fracturing, etc. Some formations
may be seen at depth in mines, drill hole cores, and
large open pits, but generally these are not cut in rock
types that might be considered for large-scale stone
production.
Below is a brief outline of important consid-erations
in exploring and prospecting for stone
deposits in Arizona:
Type of Stone — sandstone, schist, marble, etc.
geologic formation; distribution
Economic factors — markets land status*
access
transportation
labor supply
Physical characteristics 1 — color and texture strength;
compressive, tensile, shear, hardness,
toughness
porosity and absorption
insulation, reflection
* See land status considerations page 38
Workability — topography
overburden
fractures
cleavage and partings
weathering
trends at depth
cutability
reserves
PRODUCTION AND VALUES
By far the bulk of Arizona's stone production
has been carried on since World War II. Gross
production figures have beer compiled from time to
time,23 26 but only since 1953 have they begun
to show consistent trends, as below :
STONE PRODUCTION IN ARIZONA
(From Area Reports, Mineral Industry Surveys,
U. S. Bur. Mines)
YEAR TONS VALUE
1954 1,205,452 $1,914,315
1955 1,600,939 2,328,566
1956 1,623,000 2,475,000
1957 2,101,000 2,982,000
1958 1,528,000 2,731,000
1959 2,468,000 3,998,000
The above figures are reportedly from mine
shipments, sales, or marketable production, includ-ing
consumption by producers. The average price per
ton of approximately $1.60 indicates that the figures
probably represent mostly production of limestone
for cement, and of :rushed rock for aggregate. Even
the lowest values (quarry prices of unprocessed rock)
of stone used for granules and for dimension stone
are in the magnitude of $4 and $10 per ton
respectively. Because of the newness of the stone
industry, and its wide range of size and distribution of
operations, accurate data on total production and
values are not available.
However, a compilation f estimates by pro-ducers
of dimension stone an flagstone, crushed stone
as used in this report, nd decorative rock used in
construction and landscaping, indicates the following
general estimate:
YEAR TONS VALUE
(wholesale-processed)
1959 75,000 $1,575,000
A more detailed account of values may be seen
from a consideration of average quarry and
9
processed prices for representative materials. For
example, in the case of marble crushed for roofing
materials, some rock is sold F.O.B. quarries; hav-ing
passed an 8-12 inch grizzly and been roughly
screened of fines less than to 3/4 inches. Here,
prices average about $4.00 per ton. After process-ing,
the wholesale market price varies from $13 to
$20 per ton, depending on bulk or bagged, trans-portation
allowed, etc. In the case of sandstone,
quarry products consist mostly of large sheets in a
variety of thicknesses as needed to supply the mar-ket.
Here, average value at the quarry is about $7.
50 per ton, in a range from $5.00 to $11.00 per
ton, depending on quality. Because of the many
different products made in processing, wholesale
prices here vary widely; small pieces of poor grade
flagstone may sell for little more than $10.00 per
ton, while special cuts will run more than $30.00
per ton.
Thus, it may be seen that in 1960, at least 85,
000 tons of stone were produced at an average
wholesale value of $21-$22 per ton. Coupled with
the retail business in Arizona, the State's stone in-dustry
may be said to be well over $2,000,000
gross.
IV RESOURCES
SANDSTONE
At the present time, production from the pop-ular
Coconino sandstone dominates the stone in-dustry
in Arizona. It probably accounts for 75 per
cent of both tonnage produced and dollar volume
of sales. Although flagstone and dimension stone
are quarried from as far east as Holbrook, and as
far west as Seligman, the town of Ashfork is
known as the center of production. Railroad cars
and trucks leave Ashfork daily with loads
consigned to all parts of the United States.
Geology and areal extent
The Coconino sandstone is a uniformly me-dium-
grained, well-cemented, generally pink, red,
or white, eolian sandstone of Permian Age. As part
of the Permian-Pennsylvanian Aubrey Group, this
formation underlies the Kaibab limestone, and
overlies the Hermit shale and Supai formation.
Stratigraphically, its thickness is from 40 feet to
more than 400 feet. Thus, it underlies the entire
Coconino plateau in northern and northeastern
Arizona.
Extensive outcrops of Coconino sandstone
Old and new—Tower of Moenkopi sandstone, and new wall of Coconino sandstone.
are found in Mohave, Coconino, Yavapai, Navajo,
Apache, and Gila Counties.11 However, due to its
position under a hard, relatively resistant lime-stone,
and over softer shales and sandstones, its
out-crops do not generally cover the very broad
areas of northern Arizona as do the Kaibab
limestone and other formations. Although not
practical as producing areas, the most extensive
outcrops are in the rim of the Colorado River and
its tributaries, crossing Coconino and into Mohave
Counties. The beds are well exposed at the Grand
Canyon.
Some of the more important areas of present
and potential production of Coconino sandstone
are as follows: In Coconino County north of Se-ligman,
the sandstone forms the slopes of Aubrey
Cliffs under a capping of Kaibab limestone. Ap-proximately
10 miles northwest, north, and north-east
of Ashfork, Coconino sandstone is exposed or
under slight soil cover over more than 75 square
miles. From east of Drake to the Oak Creek Can-yon
area, it crops out along the Coconino and
Yavapai Counties border, where it forms the
southern edge of the Colorado Plateau. In Yavapai
County about 15 miles west of Ashfork it is ex-posed
over a few square miles near Picacho Moun-tain.
In Navajo County, the Coconino sandstone
covers many square miles in scattered areas south,
southwest, and west of Holbrook; exposures in
valleys tributary to the Little Colorado River are
abundant. Less accessible are outcrops along the
Mogollon Rim in northern Gila County, and wide
areas southeast of Show Low in southern Navajo
and northeastern Gila Counties. The widest single
area of Coconino sandstone is in northern Apache
County on the Navajo Indian Reservation. Here,
the Coconino sandstone and DeChelly sandstone
are undiffrentiated.
Structure
In general, and as a formation, the Coconino
sandstone beds are nearly flat-lying. In places,
folding and faulting have created structural dips up
to more than 45 degrees, but beds dipping steeply
enough to create problems in quarrying are rare.
However, this formation is noted for its intense
cross-bedding. Stratigraphic beds are from thin
seams to more than 20 feet thick, but within these
beds the arcuate cross-bedding is dominant. Thus,
in quarrying, thin sheets are split along these ar-cuate
lines. A single zone of cross-bedding is
some-times only 20-30 feet in length, but more
often the best quarries are in zones up to more than
100 feet long.
Fractures across the bedding are not closely
spaced. Parting is generally fair to excellent, but
some massive zones 1-3 feet thick are present.
Most parting surfaces are smooth and nearly flat;
surfaces with ripple marks are sometimes found.
Composition and physical character
The Coconino sandstone consists essentially
of rounded grains of quartz which are cemented by
silica. As a formation, other materials are present,
mostly as thin seams of clay minerals, mica, and
secondary silica, calcite, and gypsum. Inasmuch as
these thin seams are usually culled in quarrying,
the rock produced is an even-textured, quartz
sandstone. Of this rock, the silica content is
generally more than 90% and sometimes more than
97%. Minor amounts of feldspar, mica, and iron
oxide are the most notable accessories; heavy min-erals
are present in academic quantity only.
Color variations are due largely to the quan-tity
of iron oxide present. Gradations from white
through pink to red are dominant; such variations
are broad in scale, both vertically and laterally.
Thus, any single quarry usually produces only one
color with small variation. In some quarries, the
white tends to gray or to pink, and the red tends to
tan, buff or to pink. Rarely, yellowish, purple,
lavendar, and even banded colors are found, but
not in large quantities.
Porosity varies from approximately 7% to as
much as 19%. Moisture content varies from quarry
to finished stone; rock in place is usually damp, but
tends to dry quickly on exposure. One sample of
finished stone tested 0.3% moisture.* Compres-sive
or crushing strength is generally high, but may
vary according to cementing and weathering. Sam-ples
from the Navajo Indian Reservation tested is
from 2,225 pounds per square inch to 12,975 psi,
with an average of 5,382 psi. However, three sam-ples
of quality dimension stone* tested 14,795,
* Dunbar Stone Co., Ashfork, Arizona
11
013,450, and 13,993 psi.
Weathered rock, that is rock buried in soil or
within a few feet of the surface, tends to be gray, if
white at depth, and maroon, if red or pink at depth. It
also is more porous, may be friable (crumbly), and is
weaker or lower in compressive strength.
Production
To the uninitiated, production of flagstone and
dimension stone from sandstone beds may seem
fairly simple. Most pieces of "float" seen on mile after
mile of 'surface may be attractive for a stepping stone
or two in a garden or patio, but production of
specified sizes, consistent colors, and uniform
strength, all in large quantities for demanding
markets requires careful exploration, skilled
quarrying, and efficient handling. Present practice is
as follows:
1. Prospecting for likely quarry sites. Consid-erations
are accessibility, terrain, and transporta
tion terminals, as well as quality of rock. Explora-tion
usually consists of finding an exposed bed of
proper angles of cross-bedding in a wash or valley, or
of bull-dozing the surface in timbered or soil-covered
areas.
2. Overburden or weathered rock is removed by
bulldozing or simple quarrying; sometimes blasting is
done to develop a back seam to work toward.
3. Approximately 4-inch thick sheets are wedged
and barred from in place. Massive beds unsuitable for
splitting are left as islands, or cut around and bull-dozed
to waste pits.
4. Sheets are split by wedging, and broken to
size for handling, and graded and stacked on edge.
Handling in quarries is aided by roller conveyers and
by rubber-tired, 2-wheel carts than can handle up to
500 pounds.
5. Graded rock is loaded on flat bed trucks and
hauled from quarries to cutting yards. Grad-
Arcuate bedding in Coconino sandstone beds rise to right and left of truck in bottom of "trough".
12
ing in quarries is by size, color, firmness, smooth-ness,
lack of scale, etc. Some operators market their
products at this point, hauling to dealer's sales yards
or to consumers in cities, or selling by contract to
cutters who further process the stone; sales are by
weight.
6. At cutter's yards, the stone is again sorted, graded,
sized and cut to dimension. Cutters are the "guillotine"
type, hydraulically operated. Flat sheets of stone up
to 12 inches thick, and as much as 5 feet in longest
dimension, move under the cutter blade on rollers.
The cutter consists of a row of "teeth", each powered
separately, which are lowered in unison to the surface
of the stone. The individual teeth fit any irregularities
in the
surface. Power is applied, and the teeth snap the
stone, creating a "split face." Eleven of these cutters
of different capacities are now in use in Arizona.
7. Finished stone is again graded by cut di-mensions
and stacked on pallets, bound with steel
tape, and in some cases covered with paper or plastic.
Palleted stone is stored in yards, then loaded on
trucks or railroad cars for shipment to dealers, or
direct to jobs.
8. Flagstone is often transferred from quarry
trucks to docks, and then loaded direct to cross-country
trucks or railroad cars for shipment.
9. Recently one operator installed a wire saw.
Massive pieces unsuitable for splitting, are rolled
Quarry in Coconino
sandstone, showing wedging,
waste, and stone
stacked for shipment.
Guillotine
stone cutter in quarry
of Coconino sandstone.
13
14
under the saw on tracks. A continuous,
multiple-strand wire on large reels runs over the
slab immersed in abrasive grit, cutting large,
thin sheets.
In order to meet quality demands, the above
production procedure involves considerable
waste. Approximately 1/3 of the rock handled
in the development of a quarry is culled into
waste or "muck" piles. During quarrying 2/3 to
as high as 80% of the rock handled is wasted
off. At the cutting yard, again about 1/3 of the
rock brought in is ultimately waste. some
operators say that after a quarry is developed
and is operating efficiently, the waste rock can
be held to 60% of the total handled.
Shipping
Coconino sandstone is shipped by both rail-road
and truck. A main line of the Atchison, To-peka,
and Santa Fe Railroad trends east-west
across the state, and through major areas of
stone production. The largest rail shipments
are made from Ashfork and Williams. Most of
the stone destined for points in Arizona is
hauled by truck. Also, large quantities are
shipped out of the state via truck. particularly
to the west coast.
Some Coconino sandstone producers prefer
shipment by rail, but customers often prefer
truck delivery. Trucking allows for "back door
delivery" to individual jobs or to dealer's
yards, and obviates double handling. In
addition, large dealers in construction materials
may haul with their own trucks, and some
trucking companies are also in the materials
business. The larger producers ship
approximately equal amounts by truck and rail.
Loads are. of course, larger on railroad cars. (
See discussion of transportation and freight
rates be-low.)
Currently. approximately 70% of Coconino
sandstone produced is shipped to the west
coast. particularly to Los Angeles. San
Francisco, and Seattle. About 10% is used in
Arizona, and 20% goes to midwest and eastern
markets. Some is being shipped as far as
Alaska. Canada, and Hawaii. With only the
post-war period of development, Arizona's
Coconino sandstone is becoming well known
throughout the United States.
Costs
Under present conditions, and granting con-siderable
variation between different operators,
the proportions of costs for extracting and
processing Coconino sandstone are
approximately as follows:
Quarrying 30%
Haul quarry to yard - - - - - - - - - - - - - - - - - - 9%
Cutting, grading, packaging - - - - - - - - - - - 30%
Haul to destination (customer)
Overhead, development, profit - - - - - - - - - 31%
Specifications, products, trends in use
The qualities that make Coconino
sandstone popular are due to several
characteristics that make it an excellent
building stone. First, of course, is its lasting
natural beauty. Attractive colors are avail-able,
and coupled with its general linear form the
stone is highly adaptable architecturally. The
popular, informal, rustic effects may be
attained, as well as the more formal
requirements of public buildings, churches, and
office buildings.
Physical characteristics of this stone also make
it desirable. It is durable, it does not contain
minerals that oxidize or weather, causing
stains, it can easily be kept clean, and it can be
cut to clean edges. Moreover, it competes well
with brick and other manufactured materials in
close tolerance to dimensions. One producer is
marketing 117 sizes, with thickness of 1 / 16
inch intervals. Either, or both split faces and
parting surfaces may be ex-posed. Special
orders may be filled to the most ex-acting
architectural needs. Flagstone in large sheets is
desirable for particular purposes. Thus, variety
itself allows a wide range of uses.
Prior to World War II, only small amounts
of dark red, weathered, surface rock were
available; the unweathered rock beneath the
soil had no value. This flagstone was used
primarily for very rustic settings, and although
considerable amounts are sold today, the trend
in quantity has been to semi-formal uses. As
the Coconino sandstone be-came popular, a
basic change in stone use was taking place.
Due to new developments in use of steel and
cement, demand for stone blocks for structural
purposes was supplanted by a much greater
need for decorative veneers, facings, and
15
Stationary wire saw cutting Coconino sandstone.
urn. Specifications became more rigid. In order to
meet both design and structural needs, new produc-tion
techniques from quarry to final delivery had to
be devised for this stone. Thus, grading in quarries
assures firm, smooth-surfaced rock of consistent
color; the new, multi-toothed, guillotine cutter makes
cleaner split faces; close tolerance in thickness
allows designers freedom and promotes speed and
efficient use of material by masons.
As a result, products now being produced are
numerous. Large and small operators produce flag-stone
in a variety of colors, thicknesses, and grades.
Cut stone is produced in thickness from 1/2 to 12
inches, and in forms for ashlar strip for veneer, for
treads, sills, lintels and copings. Table tops and large
sheets are available. Broken stone is available for
informal landscaping. Colors may be matched, and
special orders for extraordinary products are
solicited. At least one company is packaging do-it-yourself
kits of stone cut to dimensions suitable for
building home improvements, such as barbecue
fireplaces and planters. At least one company is
marketing sized and color-grade granules for roof-ing.
Problems
Some of the problems facing the sandstone in-dustry
in Arizona are normal to the growth of any
new industry. Developing new markets and new
products, meeting more and more rigid specifica-tions,
and developing research are common needs.
other problems are peculiar to Arizona's sandstone
industry:
1. A skilled labor force has had to be created.
The State's small population, and location remote
from traditional stone producing areas conspire to
provide few experienced stone workers. As
fluctuating markets are becomin stabilized, working
conditions are becoming better.
2. Handling of waste is a problem that will
eventually be reduced, possibly by new by-products,
or by mechanization, or by improved quarry tech-niques.
At present, demand for high quality forces
high waste factors on most operators.
16
3. Mechanization has had to grow with the
industry and markets. A few years ago, nearly all
work was done by hand. Today, light and some
heavy machinery are used. As the industry grows,
the eventuality may be machines designed expressly
for handling Coconino sandstone.
4. Improvement of products is a continuing
problem. Although a certain amount of sandstone
will always be demanded for its unique characteris-tics,
volume production and sales will depend on
meeting competition of brick, artificial stone, alu-minum,
glass and other materials that may be sub-stituted
for stone in designs. This means primarily
holding costs down by efficient production, and
making a product that may be installed easily and
cheaply.
5. New exploration techniques are needed to
provide good quarries. Again, as the industry grows,
capital will become available for more thorough
field exploration, and research may develop criteria
for choosing quarry sites.
In the total picture, none of the problems
appears insurmountable. Resourcefulness, determi-nation,
and dedication to quality have already made
the Coconino sandstone famous. Operators have
confidence in their raw material, and end users have
confidence in the products.
Moenkopi formation
Sandstone from the Moenkopi formation (Tri-assic)
has been used extensively for construction in
Northern Arizona, and has been shipped out of
Arizona as building stone. The Moenkopi formation
is exposed over wide areas in Navajo and Apache
Counties," and in northern and eastern Coconino
County. It consists of uniform shades of maroon and
chocolate-colored sandstone and shale beds. The
sandstone occurs in beds from a few inches to several
feet thick, separated in places by thin partings up to
thick beds of shale. The sandstone is generally
massive within beds, and does not split easily, as
does the Coconino sandstone. Although vertical
jointing is common, large blocks may be quarried in
places, and the stone may be cut and shaped. Fairly
new buildings on the campus of Arizona State
College at Flagstaff are made of sandstone from the
Moenkopi formation.
Moenkopi sandstone deposits along the rail-road
from Flagstaff to Holbrook have been quarried
extensively. This hard stone commonly caps mesas,
making quarrying somewhat easier. Deposits on the
Navajo Indian Reservation are reported to be good
for dimension stone.
DeChelly sandstone
In a description of dimension stone on the Na-vajo-
Hopi Indian Reservations, H. Wesley Peirce
gives considerable data on the DeChelly sandstone (
Permian) . Comparisons are made with the Coco-nino
sandstone. Regarding stone as a whole in this
area, he reports, "Of the sandstone deposits, the
upper unit of the DeChelly sandstone offers the best
potential for a good commercial stone."
MARBLE
Occurrances of marble as a geologic rock type
are numerous but widely scattered in Arizona. Many
varieties are available, and many deposits have had
intermittent production. Past production includes saw
blocks and polished slabs, but current production
consists almost entirely of crushed marble for
terrazzo, roofing materials and exposed aggregate.
Increased markets, and the installation of modern
extraction and processing facilities could make
Arizona marble compete favorably with any other
source of this traditionally elegant stone.
Due to the variety of types of marble and of
geologic settings, neither a general description such
as for the Coconino sandstone is sufficient, nor are
detailed descriptions of individual deposits appro-priate
here. Therefore, the following consists of
pertinent general features, with some detail con-cerning
certain regions having common character-istics.
Geology and Areal Extent
Geologically, marble deposits are generally treated
as a part of limestone and dolomite stratigraphy.
That is, the basic sedimentary units are limestone and
dolomite, and these have been more or less
metamorphosed to marble. In some places, the
metamorphism is local, creating small and ir-regularly-
spaced marble deposits, and in other places
the marmarization is continuous and wide-spread.
The type of marble in any deposit is due
17
R e c e n t u s e o f Moenkopi s a n d s t o n e .
essentially to first, the nature of the original for-mation,
its composition, bedding, intercalated lay-ers
such as shale and sandstone, fossils, and struc-ture.
Secondly, the types and intensity of meta-morphism
determine the character of the marble.
Thus, if a pure limestone, white and without inter-calated
beds of shale or sandstone, has been sub-jected
to folding (dynamic metamorphism) only,
the mineral calcite (CaCO3) making up the lime-stone
may be recrystallized to a white and other-wise
featureless, massive marble. On the other
hand, an impure limestone, perhaps dolomite9 (
CaMg(CO3)2,) containing iron and other colored
oxides, and containing shaley and sandy partings
or beds, may have been subjected not only to
folding and faulting, but to intense thermal
metamorphism, and metmorphism created by the
introduction of other materials through veins or
impregnation by solutions. Here, obviously, the
resulting marble will be greatly different from the
original
rock. It may be colored, possibly with several
hues, veined and streaked with new minerals, or
the original rock may have been fractured and the
fragments cemented by a metamorphic matrix.
Thus, the more abundant the variety of original
and introduced minerals, and the more intense the
crustal movement, heat, and pressure, the more
complex in color and texture the marble will be.
It may be seen that the more varigated mar-bles
have undergone severe changes that obscure
the original character of the limestone formation.
Age correlations are, therefore, difficult at best. In
Arizona, although some Cretaceous limestones are
locally marmarized, the bulk of the marble de-posits
are Permian to Devonian in age. In some
cases, early detailed dating has been abandoned
for the general age of Paleozoic undivided," or
even Paleozoic and Mesozoic undivided. Also, it
may be seen that contrary to the consistently simi-lar
geologic settings of deposits of Coconino sand-
18
stone, marble deposits are likely to vary greatly even
in the same region.
Marble deposits are particularly abundant in the
southern and western parts of the state. De-posits that
have been exploited, although not all inclusive, may
be grouped roughly as follows:
1. Harquahala Mountains
2. Tucson region
3. Dragoon and Chiricahua Mountains
1. Harquahala Mountains, including the Little
Harquahala Mountains.
Here, Paleozoic and Mesozoic limestones have
been locally marmarized in a zone trending north-east
from about 10 miles southeast of Hope in Yuma
County, across the boundary and into Maricopa
County to about 12 miles southwest of Aguila. In a
country rock of granite, gneiss, and schist,
sedimentary beds have been altered to marble and
quartzite largely by metamorphic action related to
Cretaceous andesitic volcanics, and diabasic dikes.
Probably the best exposed marble, and fairly
representative of the area is in a zone on the north-west
side of the Harquahala Mountains, where
limestone with intercalated shale seams and limey
sediments have been folded and faulted and intruded
by basic material. Irregular masses of dark gray, dark
brown, and reddish brown, veined marble are present
together with irregular masses or large blocks of
white, pink and green marble. On the weathered
surface, the former is dark brown, while the highly-colored
marble is largely a dirty white or gray color.
Production in the area appears to have been
concentrated on the brightly-colored stone. This is
probably dominantly white, but is colored pink and
green near veins and dikes. Metamorphism pro-gressed
away from the intrusive features, largely
along original bedding planes. The resulting stone is
vari-colored; in places is consists of alternating pink,
green and white beds of various thicknesses from less
than an inch to more than one foot thick, and in other
places a mottled pink and green is present. Some of
the original shaley seams have been converted to a
greenish-gray mica.
This attractive rock appears to he localized in
large blocks, at most several tens of feet in longest
dimension. The dark, reddish-brown portion is mostly
dense, fine-grained, and tough, probably with some
silification. The colored facies are fine to coarse-grained,
dense in small units, but tend to part along
veins and micaceous bedding planes; they have a
frosted appearance in both fresh fractures and
polished slabs.
2. Tucson region.
Deposits of white marble are being exploited
north, southwest, and southeast of Tucson. In Pinal
County, north of Tucson and about 5 miles southwest
of Oracle Junction, a small area of coarsely-crystalline
marble dated with Carboniferous and
Devonian formations occurs on Precambrian granite
country rock; the total area of the marble deposit is
less than one square mile, but substantial reserves
are present. Original bedding and stratification have
been lost. As deep as present workings show, the pure
white, dense rock is fairly highly fractured.
Approximately 30 miles southwest of Tucson,
along the west side of the Sierrita Mountains, Pale-ozoic
beds are present in northwest trending bands.
The formations are up to mile wide and extend over
more than 8 miles. Marmarization has generally
produced a massive to highly fractured, fine to
coarsely crystalline, white to gray marble, being
exploited for roofing and other crushed rock uses.
The geology of the Sierrita Mountain region is
complex. The Paleozoic beds lie within an area of
Cretaceous sediments and granitic intrusions. These
have been affected by intrusion of both Cretaceous
and Tertiary lavas which, together with intense
faulting, further complicate the picture. Nevertheless,
in any one locality, the geology of substantial
deposits of marble may be determined.
In areas currently being worked, pure white mar-ble
is sought. Exposures show considerable variation
in color, texture, and fracturing. Discernible bedding
is fairly regular, but fracturing is also fairly intense.
The rock breaks along what may be bed-ding planes,
with beds being 2 inches to 2 1/2 feet thick and an
average of about 9 inches. Iron stain and some pale
pink and green zones are present. In addition,
apparently discontinuous sandy and shaley facies are
present. The white marble is re-
19
ported to be a very high lime rock.
Approximately 27 miles southeast of Tucson,
and 6 or more miles south and southeast of Moun-tain
View, other deposits of white marble are
being exploited. Here again, Paleozoic beds occur
in complex structural relations with Cretaceous
sediments, and with younger granite and diorite
porphyry intrusions; some of the marble may be
Cretaceous in age. Dirty-gray on the weathered
surface, the marble is brilliantly white, and is
medium to coarsely crystalline in fresh exposure.
Fracturing is fairly intense, but none of the
quarries extend to very great depth.
In the northwest corner of Santa Cruz Coun-ty,
about 3 miles east of Amado, Paleozoic beds
include another deposit of white marble that has
been quarried in the past. The areal extent is not
great, but local reserves may be large. Here, the
Paleozoic beds have been intruded by a Laramide
granite.
3. Dragoon and Chiricahua Mountains area.
Perhaps the best known marble deposits in
Arizona occur in Cochise County at the north end
of the Dragoon Mountains and the north end of the
Chiricahua Mountains, grouped here because of
proximity and common historical development. In
1909, L. R. Ligier, the pioneer marble prospector,
stone mason, and stone sculptor, staked claims for
marble on Federal land in both areas. Due to claim
jumping, bitter litigation ensued. In the 1920's,
after the death of the far-sighted pioneer, the
claims were perfected.
At the north end of the Chiricahua Moun-tains
approximately 15 miles southeast of Bowie,
deposits of massive, white marble with dark veins
occur. Here, Cambrian beds of Abrigo limestone,
Carboniferous and Devonian beds, and Cretaceous
sediments have been folded and faulted into com-plex
relations with Precambrian granite and schist.
The marmarized rock is fairly widespread, with
Outcrop of colored marble near Wendon.
20
large reserves. The stone is mostly dense, massive,
and moderately free of fractures.
Spectacularly-colored marble occurs at the north
end of the Dragoon Mountains, southeast and
northeast of Dragoon. A number of quarries have
been opened here, and are scattered over an area of
more than 10 square miles. Granting some variation
within quarries, in general a single color or pattern
may be produced from a particular de-posit.
Available colors are black, white, pink, green,
maroon, gray, cream, black with gold colored veins,
shades of yellow, a combined gray and gold, and a
gray and vari-colored, fossiliferous breccia. In
addition, a "Serpentine marble" said to resemble onyx
has been reported.
In this region, the structure and metamorphism
of the marmarized beds are particularly complex 12
Paleozoic limestones and dolomites of the Naco
Group, together with Cretaceous sediments (Bisbee
formation) are intensely folded and faulted, and have
been intruded and otherwise affected by Tertiary
granite, dikes and other igneous rocks. Structurally,
the sedimentary formations are tightly folded
anticlines and svnclines with axes trending north and
northwest. In places, limits of the folds have been
sheared by faults trending roughly parallel to the
fold axes; cross faults are also common. This
complex of sedimentary rock is bounded on the south
and northwest by Tertiary granite and other igneous
rocks which probably also underlie the sedimentary
rocks at shallow depth. The metmorphic effect of the
young intrusives, together with the intense tectonic
deformation, has been to alter the original rocks
nearly beyond identification and correlation. The
combination of impure (shaley and sandy) carbonate
rocks, intense metamorphism of all kinds, and
introduction of plutonic materials has created the
present, highly-varigated in color, veined and
patterned
marble. Bedding and stratification are esentially
absent, faults and fractures have been filled and
recemented with metamorphic minerals, and in
places, brecciated rock is suspended in matrix of
marmarized limestone. Only detailed study of the
area can yield an accurate and complete description
of the rocks.
Composition and physical character
In the Harquahala region and the Dragoon and
Chiricahua Mountains, the marble is so varigated in
color and texture as to lack consistent chemical
composition. Doubtless, analyses of the highly
metamorphosed rock would show high ratios of
silicon. magnesium, iron, etc., to calcium carbonate.
However, an analysis* of white marble fines from a
crushing operation near Dragoon is as follows :
CaCO3 98.00%
SiO, 0.62%
MgCO 0.39%
R2O3 0.80%
99.81%
Also, the white marble in the Tucson region is
generally "pure" consisting of 97 percent or more of
calcium carbonate.
The composition of the highly-colored, veined,
and varigated marbles in the Dragoon Mountains, is
complex, by virtue of the new minerals created by
metamorphism. Basically, the original limestones and
dolomites contain impurities of quartz, iron oxide,
and clay minerals. High temperatures and the
introduction of new elements from nearby igneous
intrusions have created a number of metamorphic
minerals. Part of the green color is due to chlorite, an
hydrous silicate of aluminum, magnesium and
ferrous iron; and green, reddish, yellow, and even
black colors may be due in part to serpentine, an
hydrous magnesium silicate. Mica of various colors is
also present, and wollastonite, a calcium silicate is
reported in some of the marble; rarer minerals such
as lime garnets further complicate the composition.
Of course the ubiquitous oxides of iron are
responsible for much of the col-oration, including not
only shades of red, but yellow, green, brown, purple,
and black and cream.
The attractiveness of the stone is enhanced by
the colors and textures, streaks, bands and patterns
created by metamorphism and the attendant min-erals.
But large amounts of these minerals may
weaken the rock, complicate cutting and polishing,
and causes pitting and staining in use. In both the
Harquahala and Tucson regions, the marble is firm
and dense in small fragments up to as much
*Courtesy of Mr. D. G. Ligier, Dragoon, Arizona
21
as 2-3 feet in longest direction. But present quarry
faces show fairly closely-spaced fracturing and
jointing. This may be due to current quarrying by
blasting for granule production, or to the fact that
few, if any quarries have been exploited to depths
well below the weathered and fractured surface
material. In the Dragoon and Chiricahua Mountains
saw blocks more than 6 feet in length, and a
minimum of 2½ - 3 feet in thickness have been pro-duced
in quantity. Here too, the quarries have not
been developed to depths assuredly below the
weathered zone. Deposits near Tucson are being
worked primarily for crushed stone for roofing, ter-razzo,
plaster, etc. The purest white reflective stone
is sought. Thus, sandy and clayey seams are avoid-ed,
but in places the accompanying iron stain causes
rejection of gray and yellowish stone.
The weight of the Arizona marbles is neither
heavier nor lighter than normal. Dragoon marble.
presumably originally dolomitic and containing
heavy accessory minerals, has been tested at 186
pounds per cubic foot. High lime marbles made
dominantly of calcite, may be as low as 170 pounds
per cubic foot.
Production, products, shipping, and costs
Two general types of construction materials
have been produced from Arizona marble deposits;
one, cut and polished slabs, sheets and blocks, and
two, granular materials for roofing, terrazzo, plaster,
copings, exposed aggregate, and landscaping.
By far the largest part of the marble produced
for cutting and polishing has come from the Dragoon
and Chiricanua Mountains. As much as 4,000 tons is
reported to have been produced in this area around
1950, when substantial production of saw blocks was
attained. The blocks were shipped to California,
Missouri, and New York, and as far as Canada, where
they were cut, polished, and finished to flooring, wall
facing for store fronts, fire-places and interiors and
monuments. No large-scale, permanent cutting and
polishing mills have been established in Arizona.
Saw blocks were produced by first clearing a
face in firm rock. Then pneumatic drills (drifters) on
rigid quarry bars cut rows of holes on all sides,
followed by broaching, and the blocks were
loaded on trucks and hauled to the railroad for
shipping. Attempts were made, to make blocks ap-proximately
6 feet long and at least 2 / 2-3 feet in
width and thickness: smaller sizes are acceptable,
but less desirable.
The cost of quarrying marble saw blocks can
vary widely, due largely to the waste or recovery
factor. After a quarry is well established, a basic
cost of $1.50 per cubic foot is expected: larger
blocks not only cost less per cubic foot to quarry,
but bring better prices. Colored marble should sell
for $7.50 per cubic foot up - $15.00 per cubic foot
would probably be normal in standard blocks. 10-
10½ square feet of slab or sheet marble are ex-pected
from 1 cubic foot. After polishing, prices of
colored marble are in the magnitude of $4-12 per
square foot.
Today, the only marble being produced for
cutting and polishing is in small blocks which can be
cut and finished on light equipment. Small pro-duction
for copings, fireplace fronts and special jobs
is reported from several areas, including the quarries
of pink and green marble near Wendon.
The bulk of today's marble production in Ari-zona
is granular or crushed stone. Nearly all of the
active quarries in the Harqualhala, Tucson, and
Dragoon-Chiricahua regions have at least intermit-tent
production, and quarries in several other areas
are reported to have had substantial production in
the past. At least 4 plants are producing regularly, if
not continuously.
After prospecting by examination of outcrops
and bulldozing surface material, production of
crushed marble entails first removal of overburden.
Most present quarries are on hillsides, where over-burden
is light and can be pushed to lower eleva-tions
away from actual quarry sites. This is followed
by air drilling and blasting, with heavy charges to
induce fragmentation. Broken rock is moved by
front-end loader to a truck which hauls to a grizzly.
One operation includes a shaker screen under the
grizzly to remove fines, clays and dirt. Another
operation uses a dragline to remove broken stone
from the quarry to a truck loading arrangement.
From the grizzly, the stone is truck-hauled to proc-
22
essing plants. Processing usually consists of
passing the stone through a grizzly, through
primary jaw and secondary roll crushers, screening
to size with return of oversize, and bagging. With
this general process, specifications are considered
easy to meet.
Granules are produced in all gradations from
fines to 2 inches in size. Larger pieces, including
rubble are produced for masonry and landscaping.
The bulk of the white marble of the Tucson area is
produced for roofing granules which have a high
insulation factor through reflection; white terrazzo
chips are second in demand. 65-70% of the colored
marble from the Dragoon Mountains is used as
terrazzo, with roofing material demands being sec-ond.
Considerable colored, rough marble for wall
work and decoration is produced. Other uses are
growing, but are currently minor. Much of the
Tucson area marble is consumed in Arizona, with
some shipment to the west coast. Destination of the
colored marbles is about evenly divided between
Arizona and California, with eastern markets be-ing
developed.
For the two basic uses, prices F.O.B. plant are
approximately:
White Colored
Roofing granules $15-18/T $19/T
Terrazzo $15-19/T $22-30/T
Costs of producing crushed marble vary ac-cording
to types of operation, haul, and waste.
Quarry waste varies considerably, being 2-5% in
established colored stone quarries, and as high as
35% in relatively new white marble operations.
Processing waste is about 15%, including 2% culls
and 13% powder. Powders are generally saved for
possible future use.
Reported quarry costs vary from $2.00 to $4.
50 per ton, and processing is about $9.00 per ton.
Truck haul over rough roads for any appreciable
distance may be as high as 10¢ per ton-mile,
Serrated quarry face due to removal of marble saw blocks.
23
with haul on pavement being 5¢ - 7¢ per ton-mile. A
breakdown of average costs is summarized:
Specifications and trends
Presuming availability of colors, the require-ments
for crushed marble are few and can be met.
Sizing must be accurate, the particles must he clean
and free of powder, and colors must be consistent
and not subject to stain.
On the other hand, specifications for dimension
stone, monuments, and statuary marble are far more
rigid. The stone must be firm, cut smoothly, take a
high polish, and have consistent color, veining
patterns, and fossil and breccia distribution. It must
be free of minerals that weather to pits, holes, or
stains. Statuary and memorial marble must be free
of any structural flaws. Unless vein patterns are
desired, specifications for white marble slabs
include freedom from stains, discolorations, and
veins and cracks; closer attention is given to firm-ness
than with highly-colored and textured stones.
Traditionally, marble chips have been used for
terrazzo. Experiments are made with other ma-terials,
but to date no substitute or alternate has
provided serious competition. The infinite design
possibilities of terrazzo are beginning to capture
builder's interest as their demand diminishes for the
quick, cheap, rudimentary construction that
followed World War II. Also, more efficient grind-ing
and polishing equipment, as well as the pre-casting
of both slabs and shaped units should re-duce
costs. Cost of terrazzo chips could be substan-tially
reduced by larger volume production at quar-ries
and procesing plants.
The use of marble granules for "mop down"
roofs has grown with the development of low angle
roofs. Here the architectural trends probably
determine most of the demand; likewise for marble
granules used as exposed aggregate and in copings
for swimming pools and other structures.
For marble used as dimension stone, there is a
reawakening to the adaptability and beauty of this
ancient stone. Few rock types are easier to cut, and
no polished surface can exceed the interest of
texture, pattern, and color. This, together with high
durability and strength, and low maintenance. make
it fitting for most decorative architectural
requirements.
Arizona marble can compete in quality and
beauty with the best European sources. Moreover, it
is one of the few highly colored and patterned
marbles in the western hemisphere. Varieties are
exceeded only by the reserves, of which colored
stone alone are in the hundreds of million of tons. If
less than 1/10 of estimated reserves are suitable for
cutting and polishing, more than 7 square miles could
be covered with marble, each square mile with a
different color or pattern.
Problems
Because of differences in production tech-niques,
products, and markets, the problems of in-creasing
and stabilizing crushed marble production
are considerably different from those connected with
polished marble.
Techniques for quarrying and processing
crushed marble are fairly well established for mod-est
production. The primary goal at this point must be
increased markets. Larger demand for terrazzo, 'mop
down' roofs, and exposed aggregate in construction
will require the greatest increase in production.
Substantial increases in production will provide a
basis for more mechanization and eventual lower
prices for products. Stability will accrue only when
the products are consistently competitive with other
building materials. In addition, methods should be
devised for more accurate exploration of deposits. In
some quarries, extraction costs are unduly high
because new production sites must be found before
an optimum amount of material has been removed,
Geologic examination, coupled with exploratory
drilling of properties could remove much of the
hazard of unanticipated shaley, sandy,
24
24
and stained zones. Also, more consistent rock, al-lowing
closer quality control may be found at greater
depths below the weathered zone.
Renewed production of Arizona marblc for
polishing will consist, in essence, of starting a new
type of industry in this area. with problems of de-velopment
of deposits and production techniques,
creation of markets, and meeting present day speci-fications.
The problems may be grouped as follows:
1. Proper choice of deposits to be worked, based
on geologic examination and drilling, must
be made to insure adequate re-serves and
efficient production with the least waste.
This may require some development work
to obtain stone from depths below surface
weathering.
2. Financial requirements will probably be
large, relative to other stone operations. The
built-in difficulties attending small-scale
extraction operations in today's economy
are well known. Indeed, it is probable that
the only successful production will be
obtained by an operation including not only
quarrying of saw blocks, but cutting and
polishing and marketing the stone for final
use. Mechanization is essential, and the use
of the latest and best production techniques,
such as wire saw quarrying of blocks, is
indicated.
3. Standardization of shapes and sizes is es-sential,
in order to compete with other
materials in cost of installation. Large de-mand
is most likely to come from building
and other construction, where the choice of
materials to be used often depends on the
ease and speed of handling.
TUFF
Tuff may be considered at this time as a
neglected stone. Yet its unique characteristics give it
a potential of becoming a standard construction
material in modern practice. Being light in weight
and easy to shape, its history as a fundamental
building material is ancient in many parts of the
world. It has been used extensively in Mexico with
unmitigated success, and from colonial days to the
present. Early settlers in Arizona found it not only
convenient to produce, but particularly functional as
an insulation from severe heat and cold. As with all
building stone, for a recent period its quality has been
overlooked in favor of the novelties of more modern
materials. But the combination of increased
population creating markets. new production
techniques. and architectural fashion trends should
renew interest in Arizona's excellent deposits of tuff.
Terminology and general geology
Specifically. and geologically, the word tuff
refers to cemented volcanic ash; a pyroclastic rock.13
18 Variations include tuffite, a general term applied to
rocks containing not only ash, but also other detrital
material both volcanic and surface in origin. Tuff
breccia includes fragments that are much larger than
ash. In a welded tuff, the particles have been
indurated or consolidated at least in part by retained
volcanic heat and gases. If, during its origin, the
tuffaceous materials flowed, the resulting rock is a
tuff lava, and may be known as an ash flow. A
common misuse is the word tufa or tufa-stone, which
properly applies to the cellular, calcareous sinter or
siliceous sinter deposits of mineral springs. Most
Arizona deposits of tuffaceous material having a
potential as building stone would more accurately be
called tuffite, tuff breccia or welded tuff, as the case
may be, but for general use the term tuff is practical.
Tuff deposits have their origin in volcanic ac-tion.
The many varieties are understandable when the
complexities of volcanism are considered. During
eruption of a volcano, not only is lava usually
emitted, but solid and semi-solid fragments, bombs,
dust, cinders and ash, as well as water vapors and
other gaseous materials are ejected, all at various
temperatures. Sometimes these materials are ejected
simultaneously, and at other times only one at a time.
Also, as these materials come up through the earth's
crust, they may break off and carry with them large
and small fragments of other rock. Finally, after
being deposited, the materials may be shoved,
reheated, fractured, covered, or intruded by other
volcanic ejecta. Arizona was an active
17
volcanic area from some time in the Cretaceous
period into the Quarternary period. Therefore,
the resulting deposits visible today are
generally complex in size, composition and
structure.
Character of representative deposits
Deposits of tuff are numerous in Arizona.
They are, of course, associated with other
volcanic rocks that are scattered throughout the
state. The range in area of deposits that have
been worked is from north of Kingman to south
of Wendon on the west, and from north of
Holbrook on the east to the southeast corner of
the state. Only deposits representative of areas
or types are discussed here; many others of
equal quality and potential exist.
On the Navajo Indian Reservation in
central Apache and Navajo Counties, deposits
of tuff in the Bidahochi formation (Tertiary)
are common. These are ably described in
Mineral Resources, Navajo-Hopi Reservations.
Arizona-Utah,16 and are reported only
generally here. At least three dozen deposits of
tuff are reported. The tuff beds are mostly
whitish-gray in color, are 2-6 feet thick, contain
some clay and sand beds, have a wide range in
chemical composition, and consist dominantly
( 7 0 - 8 5 ) of glass shards (ash,) with the
remainder "being quartz, feldspar, hornblendes,
rutile, glass and garnet fragments." the stone is
light in weight. fine-grained and porous; the
grains and fragments are not tightly bonded,
but compressive strengths of 2,000-3,000
pounds per square inch are reported.
In the southeastern corner of Cochise
County, tuff deposits are associated with
Tertiary rhyolite (lava.) In one area, a welded,
porphyritic, rhyolitic tuff (see analysis below)
is present over at least 150 acres. The stone
occurs in colors of white, a sand-colored huff,
and a soft pink. The colored matrix is dense,
fine-grained, well-bonded and en-closes
crystals of sanidine, biotite and magnetite, as
well as fragments of tuff and siliceous
material.
Density measurements of two samples of
this tuff are reported to average about 2.1,
which gives a weight of approximately 131
pounds per cubic foot. Other samples are said to
compensated in part by higher strength; the
aver-age compressive strength of this tuff is
probably well over 5,000 pounds per square
inch, and may be more than many competent
sandstones. Porosity-permeability tests of two
samples show the volume of water absorbed
per volume of rock to be 9.7%' and 4.4%. This
tuff is generally massive, and will yield large
saw blocks. It may be cut with ease with a
diamond saw, and quite adequately with a
carborundum saw.
A third notable area of tuff is the vicinity of
San Carlos in southeastern Gila County and
north-western Graham County.4 Considerable
production has been reported from several
deposits in this area characterized by Tertiary
and Quaternary volcanics, particularly basalt.
The tuff is mostly fine-grained, white to gray,
with some pumice and andesite pebbly
fragments. In places the "pebbles" are
stratified in zones. The material reportedly de
velops a case hardened effect with prolonged
exposure. It cuts easily into large blocks, and
has been used with considerable success.
In the vicinity of Clifton, Greenlee County,
an off-white tuff, largely free of "pebbles" is
easily carved and has been used locally with
success.
At Canyon Lake on the Salt River,
Maricopa County, a generally buff-colored, but
also gray and white tuff with fragments of
andesite and rhyolite has been in intermittent
production.
Another notable area of tuff is near
Kirkland in Yavapai County, where deposits
associated with
* Courtesy of Mr. D. G. Ligier, Dragoon, Arizona
29
Tertiary and Quaternary basalt have been operated
intermittently since before 1900. The deposits are
irregularly distributed over an area of perhaps a
square mile, and extend to depths of 100 feet in
places.
The stone is consistently light gray in color, and
is composed of a fine-grained matrix of glass shards,
enclosing small but easily visible quartz and sanadine
crystals, and including fragments of dark volcanic
rock. The latter fragments range in size from tiny to
pebble and cobble size; they are not evenly
distributed, and in places form strata or beds, giving
the stone a pebbly appearance. The dark fragments
are mostly obsidian and aggregates of glassy
fragments.
The stone is not as firm and well-bonded as
some other tuffs, but is correspondingly very light in
weight. Its compressive strength has been tested at 3,
200 and 3,400 pounds per square inch, and its weight
is 88-115 pounds per cubic foot. It is, of course,
highly porous, and its insulating character has been
found by long experience to be very good.
A tuff deposit notable for its unique colors is
located on the northeast side of the Eagle Tail
Mountains, Yuma County. Called "mint stone," the
rock in general has a unique soft green color, but also
includes bands of lavender, purple and white
material. The bands range from fractions of an inch
to more than a foot wide, and are composed
individually of dense, massive, welded ash to beds
composed dominantly of very coarse fragments of
purple, black, and maroon-colored volcanics with a
small awount of fine-grained matrix. Fairly large
reserves are available, but are limited by complex
structure. The tuff beds apparently lie between lavas,
and the whole sequence has been faulted, tilted, and
intruded by other volcanics. Thus, the beds of tuff are
blocky, and are not continuous over great distances.
Intermittent production is carried on.
In the vicinity of Kingman, Mohave County, tuff
was quaried in years past for extensive local use. The
stone is largely a light-colored reddish pink, with
some dark to black zones. "It is medium-grained and
fairly uniform in texture and dresses well." 20 Small,
but distinguishable phenocrysts of
biotite, feldspar and quartz are present.
Also in Mohave County, about 5 miles south-east
of Wickieup, a green stone classed as tuff is
notable. Although reserves are not large, the stone is
unique in its soft, apple green color, and that it is
opalized and otherwise silicified. It occurs as a bed
8-12 inches thick, included in Quaternary basalts,
with overburden up to 50 feet consisting of tuff and
altered tuff. The stone is hard and dense, with
varigated bands of shades of green. Current
production is under way.
Production
Much tuff has been used locally in Arizona over
many years. In 1909, Schrader20 wrote, "The most
important building stone in the region is the rhyolitic
tuff underlying Kingman Mesa." and, "The most
important buildings in Kingman are built of it." The
production history consists of intermittent operation
of many quarries; therefore, production data are
scant and inaccurate. Tuff has been exported from
Arizona in considerable quantities, but not sufficient
to sustain continued production.
Recently, more than 33,000 square feet of
curtain walls in additions to the state capitol were
made of tuff; 8 to 10-ton saw blocks were quarried
near Kirkland, and hauled by truck to a Phoenix
cutting yard, where a sand and water saw cut rough
slabs that were trimmed by diamond saw. Currently,
some quarries are being worked for rough stone for
wall facing and landscaping. Also, substantial
quantities of the green colored "mint stone" have
been quarried since World War II. Thus, although
one quarry operator believes that tuff can be
produced for about one-third the cost of marble,
production has never been stabilized on a continuous
basis.
Problems
Two problems are fundamental to growth of a
stable production of tuff. First, larger markets for
slabs and dimension cut stone must be developed.
Tuff is a relatively unknown rock type, and its
characteristics as a building stone must be called to
the attention of builders and designers. Its con-tinued,
successful use in comparatively small quan-
30
Massive t u f f .
tities over the years is not sufficient advertising in
today's rapid and highly competitive building econ-omy.
All building stones have some disadvantages;
and these must be studied with a view toward
overcoming them, or circumventing them with proper
design. Below is a general evaluation of the
characteristics of tuff :
Advantages* Disadvantages*
Light weight Low tensile strength
lower shipping cost Permeable
ease of handling high absorption
light weight construc- may be weakened b}
tion freezing when wet
High insulation quality Will not take polish
Variety of colors Some deposits thin and
Variety of textures or small
Can be worked easily
Can be cut to dimension
Compressive strength
adequate to high
Low production costs
The second fundamental problem is to establish
operations consisting not only of quarrying, but also
of milling and finishing. As in the case of marble,
integrated production from quarry to market holds
the most promise of stable success. Not only is there
an obvious financial advantage in an integrated
operation, but techniques of production may be
improved; detailed characteristics of a particular
rock may be learned in the quarry and passed on to
the benefit of cutting and trimming operations. Also,
stocks of various sized dimension stone may be built
up, and special orders are easier to fill if quarrying
and processing are integrated. It is not too visionary
to conceive of a cutting and trimming yard being
supplied saw blocks from a number of quarries, in
order to market a greater variety of products.
In addition, mechanization is essential. Wire
saws requiring little attention can be adjusted to saw
block production and slabbing; handling of saw
blocks must be systemized. Quality control
* It should be noted that some features create both de- stone may be permeable and have less strength. Also, not-sirable
and undesirable characteristics. For example, the able is the variety in character of various deposits; if low
more porous types of tuff are very light in weight and are permeability is needed, a tightly welded tuff from one
good insulators, if the pores or spaces are connected, the source may excel a very light tuff from another source.
31
Green tuff deposit in Eagle Tail Mountains. Note beds cut by dark volcanics.
must be increased by closer evaluation of deposits
and of quarry sites, in order to reduce waste in
slabbing and trimming.
GRANITE
By a casual glance at the geologic map of Ari-zona,
one may see that the state contains an un-limited
supply of granite as a rock type. Of course,
not all of this rock is suitable for building stone, but
out of the wide areas and many varieties, doubtless
numerous excellent sources could be developed. For
many years, granite has been used as a building stone
and for monuments within Arizona, but out-of-state
markets have not been developed. Probably the
largest use has been for public buildings, such as the
Yavapai County Court House in Prescott, and parts of
the state capitol in Phoenix.
Specifically, granite refers to a very particular
rock type, but practically, the term applies to all
related13 18 or "granite type" rocks, including
granite-porphyry, diorite, gabbro, and some gneis-sic-
textured rocks. These rocks are common in Ari-zona,
but are confined essentially to the southern,
southwestern and western parts of the state. Many of
the mountains in these parts of the state are
composed of granite type rocks of various geologic
ages. Because of market conditions and past access
and transportation problems, most of them have not
been prospected for possible granite quarries.
For purposes here, only a few granite deposits
are mentioned. Near Cochise Stronghold in Cochise
County, a very good, even and fairly coarse-grained
gray granite (granodiorite) can be quarried in large
blocks. In Greenlee County, north of Morenci, large
reserves of a coarse-grained granite with aplitic
veins and zones are available. This granite has an
over-all wine pink color due to dark red feldspars.
Small amounts have been quarried from large
residual boulders. A similar deposit of smaller
reserves is near Clifton. Part of the state capitol
building was built of granite from north of
32
Salome, in Yuma County. A "black" granite (gran-odiorite?)
is reported 6 northeast of Helvetia, Pima
County. In Yavapai County, inexhaustible supplies of
a dark gray to white granite (quartz diorite) are
available, particularly in the Prescott region. In
Maricopa County, abundant reserves of gray, white,
and pink granite may be found; notable are the
mountainous areas in the northeast part of the county,
and also south of Phoenix where a gneissoid granite
was quarried for part of the state capitol. Similarly,
Mohave, Yuma, Pinal, and Santa Cruz counties
contain large areas of massive granite.
Granite and related rocks have certain well-known
good characteristics for building stone. They
are particularly strong and durable, and have low
porosity; they are available in sleek homogenous
textures, or in veined and patterned textures with
swirls and irregular zones of fine-grained to coarse-grained
matrices. The stone takes and keeps a high
polish that brings out colors. On the other hand, it is
a hard and dense stone, more difficult to quarry and
cut than others.
In prospecting, assuming an available rock
satisfies needs of appearance such as texture and
color, probably the most important quality to be
determined for granite is strength in large blocks.
First, it should be noted that in arid climates such as
in Arizona, granite characteristically erodes by
disintegration. That is, being a crystalline rock com-posed
essentially of the three minerals, quartz, feld-spar,
and mica, all having different coefficients of
expansion, changes in temperature open cracks and
cleavage planes. Moisture penetrates; alternating
cold and extreme heat over geologic ages cause the "
fresh" rock to break down, or "weather" to sharp,
angular fragments. This resultant material is locally
called "disintegrated granite," and incidentally has
considerable use in landscaping and other ground
coatings. In places, outcrops of granite are weak and
punky, being in the process of disintegration to
depths of more than 10 feet. It is most important to
realize that a surface of weathered granite may
conceal an entirely different looking fresh rock at
depth, and may mask an excellent de-posit of
building stone.
Further, prospecting for firm granite should
include careful evaluation of jointing, fracturing,
cleavage, and other lines or zones of weakness. Wide
areas of some Arizona granites contain closely-spaced
joints that were formed during cooling of the
magma. These may preclude quarrying of large saw
blocks. Other areas may be massive, but contain
faults and fracture zones that must be avoided in
quarrying. Also, most even-textured granites have
more or less subtle cleavage, or directions along
which the stone may break more easily; quarrymen
know this as "grain" and "rift". Fortunately, granite is
abundant enough in Arizona that problems of
firmness and strength may be met by relatively little
and inexpensive exploration.
SLATE
Good slate in the classic sense is the least abun-dant
of the major building stone types in Arizona.
Most slate used as building stone is a hard, durable,
finely-crystalline, metamorphic rock with strong
cleavage in one plane.14 It is commonly blue-black,
known as `slate colored,' but also occurs in shades of
gray, red, green, and purple. The metamorphism that
has created slate from clay and shale beds is low-grade;
more intense metamorphism creates phyllite
and schist. Thus, in Arizona it is not generally as
common a rock type as schist.
The largest use of slate 24 has been for roofing
plates, but many other products utilize its unique
character, such as blackboards, electric panels, bil-liard
tables and laboratory and other table tops. As a
building stone it is also used structurally for
wainscoting, sills, mantels, steps, etc., and is cur-rently
a popular material for flooring.
Most occurrences of slate in Arizona are more
properly phyllite, and some are known as `mica slate.'
However, southwest of Walker, in the Bradshaw
mountains of Yavapai County, deposits of excellent
slate are reported. It occurs in shades of green,
brown, and black, and is hard and smooth, with good
cleavage. Development is said to be under way to
remove sheets for cutting.
Near Sunnyslope, north of Phoenix in Maricopa
County, a deposit of largely blue-black and green
colored slate has been worked for a number
33
of years. It tends to be micaceous, and is hard
and firm. It can be split into fairly large sheets.
No production of cut or dimension slate is
reported from this deposit, but it is highly
prized for rough, masonry walls.
Also, in the Sierra Ancha District north of
Globe, Gila County, a hard, banded "ribbon
slate" is reported. It is said to be banded in dark
shades of red, gray, and purple.
Doubtless other deposits of slate are available
in Arizona. Systematic prospecting in areas of
metamorphic rocks should bring to light much
good material for building stone. The
Precambrian rocks of the mountainous
southerly and westerly portions of the state
hold the best possibilities.
LIMESTONE
Limestone, including dolomite, is common
in Arizona, but in recent years it has seldom
been utilized for building stone. As with other
types of
stone, it has been used locally in the past; no
post-war production is reported.
Limestone is a sedimentary rock composed
essentially of calcium carbonate, or when
dolomitic, it includes magnesium carbonate. It
is characteristically dense, compact,
microcrystalline, and white in pure form. When
it has been metamorphosed and recrystallized
to the point of taking a polish, it is called
marble. Normally, limestone has been de-posited
over wide areas." Thus, the Kaibab
lime-stone (Permian) and the Redwall
limestone (Mississippian) crop out in many
places on the sedimentary plateau of northern
Arizona. In the south-ern part of the state,
several other Paleozoic and Precambrian units,
such as the Modoc, Escabrosa, Martin, Abrigo,
and Mescal limestones are present; these are
marmarized in places. In addition, lime-stone
and limey or calcerous beds suitable for build-ing
stone are included in other formations that
are dominantly shale or sandstone, as for
example,
Saw block quarry in light gray tuff.
34
limestone lenses in the Navajo sandstone.16
Clearly, limestone is abundant in Arizona,
needing market demand and systematic prospect-ing
to provide suitable production areas. The ad-vantageous
potential quarry operation methods in
Arizona merit attention here. In many parts of the
United States, suitable building stone deposits are
on nearly flat land, or in topography requiring ex-pensive
vertical lift of stone from quarries. But in
Arizona, many good deposits are located on hill-sides,
or in such topographic positions that quarry-ing
to great depths below surrounding surfaces need
not be anticipated. Particularly notable are such
formations as the Kaibab limestone, which may be
found in thick, massive beds capping mesas. Under
such conditions, large volume removal of stone
may progress horizontally rather than vertically,
and in many cases, flow of materials from source
to loading for shipment may be entirely by
gravity.
SCHIST
Schist is a rock type that is not traditionally
considered to be a common building stone, prob-ably
because it does not readily lend itself to pre-cise
cutting or shaping. Nevertheless, since World
War II, thousands of tons have been produced in
Arizona, and out-of-state shipments are becoming
a significant factor. Apparently, the variety of both
subtle and brilliant colors available has made this
stone a popular wall facing.
Arizona is peculiarly endowed with large sup-plies
of schist. Although young (Mesozoic) schist
is reported, as in Yuma County, most of it occurs
in the oldest of rocks, Precambrian in age. Rocks
of this age, particularly common in southern and
western Arizona,ll are only scantily available or
even absent in many other states. Modern architec-tural
trends requiring color and textural relief to
otherwise monolithic structures have brought nu-merous,
small quarries of schist into operation.
Production methods are simple. This meta-morphic
rock generally cleaves into irregular, platy
pieces, due to the common orientation of platy
minerals, largely mica. After overburden is re-moved,
firm rock is exposed by light blasting, and
pieces that may be handled by one or two men
are pried loose and loaded for shipment. Due also
to the cleavage, many surfaces are weathered to
attractive colors, even at considerable depths. The
material is hard, but may be shaped by masons
without extraordinary difficulty. The slabby shape
of most stone also makes it adaptable to palleting
for shipment.
Currently, the material having the so-called
desert colors, shades of red, yellow, and brown are
popular. Several small operations are being devel-oped
in the Tucson area, but the largest production
is in the vicinity of Phoenix. One of the oldest
quarries is in Sunnyslope, north of Phoenix. High-ly
colored schist is quarried north of New River in
northern Maricopa County, and near Mayer in
Yavapai County. Also, extensive deposits have
been developed elsewhere in the Bradshaw Moun-tains,
south of Prescott, and in the vicinity of Tuc-son.
MISCELLANEOUS STONE
Arizona has deposits of a number of rock types
that have been used for building and related pur-poses,
but because of lack of data, or specific po-tential
in the building industry, they are classified
here as miscellaneous stone. This does not mean
that any one of them is unimportant, or indeed,
may not become a strong factor in the stone indus-try.
A change in production techniques or con-sumer
desire or knowledge of deposits, as in the
case of schist, could warrant detailed study in the
future. Generally, their production has been erratic
and small due to their rarity, types of deposit, diffi-culty
of being worked or lack of markets. Togeth-er,
however, they comprise a group that adds to the
necessary variety of available stone, and thereby
increases the potential of the industry as a whole.
Rhyolite and porphyry
Grouped here are all of the light-colored vol-canic
rocks including dacite, rhyolite porphyry,
and tuffaceous rhyolite, that are abundant
throughout the state, excepting, of course, tuffs as
previously described. Being volcanic in origin,
they are either characteristic or related to the many
Tertiary and Cretaceous rock areas in the state, and
gradations
between them are common. As a whole, they
lack the light weight and cuttability of tuff, the
cleavability of sandstone and slate or the
ability to take polish as granite and marble.
Nevertheless, the variety of colors and
textures, and the relative abundance give them
a strong potential as building stone. Perhaps the
availability of tuff has caused them to be
overlooked.
In Greenlee County near San Carlos, a
tuffaceous rhyolite has been quarried. It is
fairly massive, reddish in color, and in places
it has attractive banding of reddish and light
colors such as cream. Northeast of Wickenburg,
Maricopa County, a rhyolite with bands and
halos of red to brown is reported. It is fine-grained
and can be cut to good building stone.
Another deposit west of Alamos Springs in
Yuma County is prized for the halo bands of
salmon-pink to red in a light gray back-ground.
Regarding halo bands, in places some fine-grained
rhyolites have a fairly regular jointing
and fracture system, allowing alteration (
oxide) to affect the rock along the planes of
fracture, and more or less into the rock,
probably along flow lines. When quarried, the
rock tends to have colored bands parallel to
fractures. Interesting and attractive patterns
and "designs" may also be ex-posed by cutting
such rock.
Of particular current interest are the many
surface deposits of both residual and
transported boulders of rhyolite porphyry.
Weathering has created shades of red, brown,
pink and even lavender that make the rock
desirable in masonry walls and landscaping.
Large areas near urban centers in Arizona
have been cleared of this surface material;
shipment out-of-state is also reported.
Basalt and scoria
In parts of the United States, this heavy,
dense, very hard, fine-grained, and generally
dark-colored rock is a major type of building
stone. Vast areas of basalt are present in
Arizona.il Although is has had local use, no
significant shipments are reported. It is
Outcrops of massive granite.
36
granite," 7 and includes other basic rocks such as
diabase and diorite. In Arizona, it is commonly
called "malpais".
Because of the weight, hardness, and subdued
and somewhat somber colors, basalt has a limited
potential as a dimension-cut building stone. How-ever,
currently the weathered basalt is popular for
masonry walls, wallfacing, and landscaping rock. In
some cases, the rounded boulders transported by
erosion are desired, and in other cases, the
weathered but more angular pieces near the out-crops
are used.
Somewhat more difficult to obtain are the
scoriaceous basalts, or scoria. This material is some-what
lighter in weight because it contains vesicules
or holes due to contained gases in the original lava.
The vesicules are often not connected, and may be
filled with white, secondary minerals. The more
representative scoria resembles clinker or slag, and
is commonly red or maroon in color. Irregular dep-osition
of scoria makes quality control difficult, but
at this time large tonnages are being sought to meet
an increasing demand.
Travertine, tufa, and onyx marble
These stones of ancient reputation occur
sparsely in Arizona. They all originate from the
same process of calcium carbonate precipitation in
springs, streams, or caves. Sometimes beds are only
a few inches thick, but may be scores of feet thick.
Travertine is a solid, layered rock, which when pure
is white, but may be colored to many hues due to
contaminating elements such as iron oxide or
organic material. Tufa is cellular in structure, and
onyx marble is banded and crystalline. All may
contain some siliceous material, and in fact, true
onyx is a variety of agate, primarily silica. Being
made dominantly of calcite, they are soft, cut easily,
may be carved, and may take a high polish.
Onyx marble, or decorative onyx is probably
the most spectacular of the three stones, and even
though deposits of travertine 6 and tufa a are present
in the state, onyx presently exceeds the others in
demand. Due to the irregular deposition of onyx,
quarrying of large volumes of consistent quality is
difficult. The market for novelties made of onyx is
well established, but the stone's greatest potential
is in building materials, such as wall facings, sills,
table tops, trims, floor tiles, and moldings. The
relative ease of cutting and polishing may make it
competitive with other textured, polished stones, in
spite of the quarrying difficulties.
In Santa Cruz County, northwest of Sonoita, a
type of onyx is variously reported as onyx marble
and travertine.6 It was found in a cavern in
limestone on the east side of the Santa Rita Moun-tains.
It is reported to be various shades of brown,
and to be sufficiently massive and firm to be re-moved
in large blocks.
Near Cave Creek in Maricopa County, green-ish
and yellowish onyx with veins of brown and red
is deposited in intimate association with basalt.
Although of fine quality, only relatively small pieces
may be removed due to shattering by volcanics.
Near Mayer, Yavapai County, considerable
onyx has been produced.26 It is white and pale green
in places, but the deposit contains much amber,
brown, and yellow stone. Several openings have
been made in a deposit that covers about one quarter
of a square mile. In one place, a large open pit,
approximately 40 feet across, has been excavated,
exposing onyx on three sides; beds here vary from
an inch to more than 10 feet thick, and are reported
to be more than 20 feet thick elsewhere. The beds
are also wavy and irregular. Adits have been dug
more than 10 feet into the vertical walls of the pit.
Excellent deposits of multi-colored onyx are
located approximately 20 miles north of Globe, Gila
County. 300,000 to 1/2 million tons of gross
material are estimated to be available with a sub-stantial
portion useable or recoverable. As many as
17 different colors of banded, crenulated, and
veined material are reported. In places, the bands
and crenulations are fine and tight. Elsewhere,
massive white and ivory colored onyx with fine
veins is present. Production consists largely of in-termittent,
surface work over the past two years. It
is believed that consistent colors and patterns can
be quarried in large saw blocks; the stone contains
some vugs that appear firm. What work has been
done indicates relatively little fracturing in the rock
and one bed is 20 feet thick over a con-
37
siderable distance. Also, the stone contains some
siliceous material, agate or chalcedony, largely
filling vugs. Due to the presence of the harder,
siliceous material, and particularly for volume pro-duction,
diamond saws are indicated for cutting.
Quartzite and Quartz
A sandstone made of quartz grains, that has
been metamorphosed to the extent that the rock will
break through the individual grains, is termed
quartzite. Impurities in the original sandstone, or
introduced by metamorphism can give quartzite
almost any color and banded effect. The rock is hard
and tough, and many varieties will take a good
polish. Quartzite cuts and polishes with about the
same ease as granite. In places such as the northeast
corner of Pima County, some quartzite cleaves along
bedding planes, yielding sheets, plates. and blocky
pieces, depending on the thickness of the beds.
Many beds are massive and several feet thick, and
could be quarried for saw blocks.
At least six quartzite formations are well-known
in Arizona," and this rock type is also found
as members in other formations, such as associated
with marble. Production of quartzite has been
meager, but the many deposits in Arizona should
get attention in the future.
Quartz, on the other hand, has been a common
building stone for many years. As a stone, the term
quartz usually refers to vein deposits, where it is
often found in shades of white or milky white. Rose
quartz is rarer, and currently much in demand.
Commercial deposits are mostly at least several
feet wide, and may compose small hills, making
extraction easier. Quartz has a hardness and
toughness equal to quartzite, and characteristically
breaks with a glassy, conchoidal fracture.
Numerous deposits of quartz have been
worked for flux in copper smelting, and these and
others can be used to provide building stone. Not-able
deposits of rose quartz are northeast of Cave
Creek in Maricopa County, in the Cerbat Moun-tains,
near Chloride, Mohave County, and north
Schist wall (lower portion) with top of exposed quartz aggregate.
38
of Bagdad in Yavapai County. Although deposits of
white quartz are generally not large in size, they are
common in all counties except Apache, Navajo, and
Coconino.
Jasper
Jasper is a hard, dense, variety of silica re-sembling
chert in some respects. It is opaque, and
occurs in colors of black, brown, and yellow, but
most commonly red; it takes a high polish. Being a
siliceous precipitate from cold water, it occurs in
large and small irregularly-shaped masses, and
sometimes in fairly widespread `beds'. Although the
hardness and irregular deposition do not give it the
large volume potential of some other stones, jasper is
considered unique and is in demand for special uses.
Jasper may be found in every county of Ari-zona,
but the best known deposits are in a wide area
where Yavapai, Gila, and Maricopa Counties meet,
between Cave Creek and Sunflower, and north along
the Mazatzal Mountains. Here, red, green, and purple
jasper, partly banded and crenulated is exposed in
many places; some of it is associated with mercury (
quicksilver) deposits. Fairly extensive and thick beds
west of Sunflower have been worked. Also, deposits
in northwest Yavapai County and Mohave County are
reportedly being opened. Out-of-state shipments of
rough, quarry run stone from various parts of the
state are re-ported.
Copper-stained stone
Currently, any rock type containing substantial
quantities, coatings, or stain of the blue and green,
secondary or oxide minerals is in demand. The
extensive copper mineralization in Arizona provides
ample supplies, not only in outcrops, but in many
mine dumps. The brilliantly colored secondary
minerals, chiefly chrysacolla and malachite,' are
difficult ores of copper to process, and are often
discarded or stockpiled at mines for later use. Where
the rock is firm, its value as building stone exceeds
its value as ore. Numerous buildings in Arizona have
wall facings of oxide copper stone, and substantial
shipments to other states attest the growing
desirability of this unique stone.
Magnesite
North of Phoenix near Rock Springs in Mari-copa
and Yavapai Counties, deposits of a white and
cream-colored rock called "magnesite" may be
found. It occurs over a fairly large area as beds at
least ten, and possibly many more feet thick. It
appears to be opalized carbonates of calcium and
magnesium. Surface material varies from hard and
firm to crumbly. Recent production has increased
markedly.
Serpentine
A "serpentine" stone in shades of pink, gray,
and purple has been reported from southwest of
Globe, Gila County. The rock is said to be banded
and fairly hard, and is being produced for shipment.
V AVAILABLE STONE — LAND STATUS AND
ACQUISITION OF MINING RIGHTS
In the future, doubtless many new sources of
stone will be developed in Arizona. The state con-tains
vast areas that are available for prospecting,
but due to the several basic kinds of land owner-ship,
mining rights must be acquired in several
different manners. For purposes of developing stone
quarries, four types of land according to basic own-ership
may be considered; 1) private land, 2) U. S,
public domain open to mineral location, 3) Arizona
state land, and 4) Indian land. These types of land
constitute 90 percent of the state; the other 10
percent consists of Federal lands withdrawn for
military purposes, parks, reclamation projects, and
other uses not open to mining. The approximate
acreage and proportions of these lands are as fol-lows:
Type of Land
Ownership Approximate Acreage Percent
Private 10,200,023 14
U.S. Public Domain 24,451,252 34
State of Arizona 10,785,564 15
Indian 19,378,795 27
Other 7,872,366 10
Totals 72,688,000 100%
Private land
Inasmuch as all of Arizona was once Federal
land, private ownership has been acquired through
patents of one kind or another, such as homestead,
mineral, and land grant patents, and the land is now
owned in fee simple. Therefore, private land is also
known as patented or fee land.
Acquisition of mineral rights on private land in
Arizona is the same as any other place. Some-times
land is bought outright, but more commonly lease
arrangements are negotiated with owners. Some
owners want a flat rental, others want a royalty on
material removed or a combination of both.
Prospecting should be done with the consent of
owners.
U. S. Public Domain
These lands are known as Federal, or simply "
U.S." lands. They consist largely of U. S. Forest
lands, and of unappropriated Federal lands man-aged
by the U. S. Bureau of Land Management.
Mineral rights for unique varieties of stone
may be acquired on open public domain, under the
mineral location laws applicable to lands in sixteen
western states. Prospecting may be done without
permit. Upon discovery of a valuable deposit,
claims which are generally 600 x 1500 feet in size,
are located, location notices are filed, and mining
or quarrying may begin. Claim monuments and
discovery work must be done according to General
Mining Regulations. One may locate and mine on
as many claims as necessary, and upon which a dis-covery
is made; neither a lease nor royalty pay-ments
are required. Under certain conditions, min-eral
claims may be patented; that is, full rights to
the land are granted the claim holders.
Under an Act of July 23, 1955, the U. S. min-ing
laws were amended to provide for multiple use
of land, restricting miner's use of the surface of
unpatented claims to those activities necessary to
prospecting, exploration and mining. Also, "com-mon
varieties" of sand, stone, gravel, pumice, pum-icite
or cinders were made non-locatable, and are
subject to disposal by sale under contract. Thus, a
common variety of stone could be removed only
under contract, and by payment of a unit price for
the stone removed.
The question of definition of "common varie-ties"
is, of course, important to the stone industry,
because rights under mineral claim location proce
dure are greater than that for disposal of common
varieties by contract. Materials which have a dis-tinct
and special value are not considered "common
varieties." It appears that such characteristics as
unique coloration, ability to cleave or be split easily
into slabs or sheets, or ability to be cut to dimension
could cause a particular deposit of stone to be
classified as uncomomn. Stone having no unique
chemical or physical properties would normally be
a common variety. There must be a market for the
material at the time of location to make it valuable
and subject to location. However, the law is so new
that few guide lines have been established, and
each deposit must be evaluated by itself. It may be
inferred that today's market requirements of high
specifications and unique appearance of products
should presume the existence of many uncommon
varieties of stone that would be locatable as mining
claims.
State of Arizona Land
State land is also subject to entry for mining
purposes; prospecting may be done without a per-mit.
Upon discovery of a valuable mineral deposit, a
claim may be located in essentially the same man-ner
as on Federal land, or according to 20-acre
claims set out by legal subdivision. Stone is included
with other minerals, without distinction as to com-mon
or uncommon varieties.
The major differences between mining on State
and on Federal land are that after location on state
land, a 20-year lease is obtained, royalty on
production is paid, and no patent proceedings are
available; also, lessees pay an annual rental of $15.
00 per claim. and hai, a preferred right to renewal
of the lease on expiration. Leases may be assigned
or transferred, wholly or in parts.
State lands are managed by the Arizona State
Land Department. Proof of discovery is required,
and for stone claims this may consist of sending a
sample to the Department, along with an affidavit
that the sample came from a particular claim. Roy-alty
is payable at the rate of 5 percent of the net
value, after deduction of cost of processing, costs of
transportation, and applicable taxes. Rules and
regulations, and instructions on procedure to
40
obtain a mineral lease are also available. Arizona
encourages mining on its land as well as throughout
the State, and a substantial amount of the present
stone industry obtains raw materials from State land.
Indian Land
Approximately 27 per cent of Arizona is Indian
land, divided into separate Indian Reservations
scattered over the state. Generally, exploration and
mining rights may be acquired by negotiation. with
individual tribes, under the supervision of the U. S.
Bureau of Indian Affairs. Most commonly, leases
are obtained for a particular area, and payment
includes a fixed rental, plus royalty. Where possible,
the use of Indian labor is encouraged.
Surface and subsurface
In addition to the above general ownership of
lands in Arizona, attention should be called to the
variations in surface and subsurface ownership. That
is, title to the surface may be held by one of the U. S.
Government, State of Arizona, private parties, or
Indians, while title to the subsurface or mineral rights
may be held by another of those four. For example,
the surface rights may be owned by the State, while
the subsurface is held by the Federal Government; in
this case, mineral claims could be located according
to Federal procedure. Or, private parties may own
the surface, but the State owns the mineral rights or
subsurface, making it subject to State mineral leases.
Most commonly, the State or private parties own
surface rights, with subsurface reserved to the
Federal Government.
In any case, this divided land ownership, which
could be called "vertical ownership," is a factor to be
considered in exploring for stone quarry sites.
Although seemingly complicated, its total effect has
been to reserve large areas for mineral claim location
under Federal or State laws. The U. S. Bureau of
Land Management and the Arizona State Land
Department make both records and help available to
determine land status.
VI TRANSPORTATION AND
FREIGHT RATES
No consideration of the economics of the stone
industry would be complete without a realistic eval-uation
of transportation conditions. Length of haul,
modes of transportation, availability of loading fa-cilities,
and freight rates loom large in the determi-nation
of whether or not a particular stone can
compete with other materials. This is particularly true
in Arizona, where the appeal of west coast markets is
strong. Not only must Arizona stone compete with
manufactured materials, such as glass and aluminum,
but it must be competitive with stone from other
states; Arizona has an obvious advantage over
eastern stone moved by truck and rail, but may not be
so fortunate regarding overseas haul, even from
foreign countries. The importance of transportation to
the stone industry may be seen by the general
location of quarries near major transportation routes.
Some quarry operators rely in part on their own
trucking facilities; others contract hauls, and use both
truck and railroad transport. Between truck and
railroad service, each has advantages that must be
weighed for operation of any given stone deposit.
The transportation of goods is a more complicated
field than many producers in all industrial fields
realize. Specialist representatives of common carriers
in Arizona stand ready to analyze, and to
recommend proper arrangements and adjustments to
meet the conditions of new and changing industries.
Their aid should be sought. Common carriers must
quote rates on any and all commodities except a few
specialties of "extraordinary value." They are
constantly evaluating rate schedules to make them
appropriate for a given volume of movement. Rates
are generally first established for a particular need.
Such rates may be applied to other similar needs even
though they may not be wholly applicable, unless
circumstances for additional and different rates are
presented by shippers. Thus, more flexibility is
available, particularly for new commodities or
forms.
Several general principles of common carrier
transportation are pertinent. Shippers should de-termine
the difference between "class" and "com-modity"
rates. The former are more general, and
apply to all of one type of carrier, and the latter are
more detailed, for specific volumes and haul routes.
Secondly, interstate and intrastate haul conditions
41
may be different, affecting rates and franchises.
Thirdly, minimum weight requirements must be
considered. For example, present truck and rail-road
rates for hauling stone from Ashfork to the Los
Angeles area overlap according to the various
minimum weight requirements. Another important
factor regarding rates is the degree of finish of a
product. Fundamentally, carrier's rates are based 1)
the work done in hauling, 2) the particular risks
encountered in handling and hauling goods, and 3) `
the wear-and-tear' and damage done to transport
equipment. It may be seen that in general the higher
value goods require higher rates, and many different
classifications are created. With stone, as with many
other products, the more finished the material, the
higher is its value. Related to this, stone producers
are becoming more interested in packaging, not
only for ease of handling, such as cut stone steel-taped
on pallets, but for protection of products, and
for merchandising of building kits. For some
products, carriers rates vary according to packaging.
Railroads
Two major rail systems serve Arizona; the
Southern Pacific Company in the southern part of
the state, and The Atchison, Topeka, and Santa Fe
Railway Co. in the northern part of the state. Both
have had limited experience in hauling stone in
Arizona, and consequently do not have detailed
commodity rate schedules for many potential ship-ping
points. Below is a general classification of
stone for rail haul, according to degree of finishing:
1. Rough quarried, or broken stone.
2. Finished not more than sawed, dressed, or
cut to shape.
3. Polished, decorated, finished.
Within the above groupings, there are, of
course, many possible stone commodities. Move-ment
of stone in the southern part of Arizona has
been erratic over many years, so quoted rates may
be unrealistic for specific commodities, but in the
northern part of the state, stone is now being
moved by rail at the following representative rates :
CURRENT CARLOAD COMMODITY RATES
FOR RAILROAD SHIPMENT
Natural stone, rough quarried, or broken
(no packaging required)
FROM: Northern Arizona, viz: Ashfork, Drake,
Prescott, Seligman
TO:
Rate per
100 lbs.
Minimum
lbs.
Los Angeles, California $0.455 60,000
.335 80.000
San Francisco, California .445 100,000
Fresno, California .415 100,000
Seattle, Washington .88 100,000
1.21 50.000
Portland, Oregon .88 100,000
1.21 50,000
Chicago, Illinois .93 80,000
Kansas City, Missouri .84 80,000
Milwaukee, Wisconsin .93 80,000
Houston, Texas .75 80,000
Other features related to rail transportation
that should be considered are loading sites and
processing sites. Most stations have public loading
tracks (team tracks) and also have some leasable
industrial sites on trackage (industry track). All
named stations have sidings, and these are more
numerous than commonly believed. Moreover, be-tween
stations railroad companies have rights of
way of an average of about 100 feet on both sides
of tracks, which under certain conditions may be
used for additional facilities. Thus, if volume of
haul warrants, processing plants may be located
adjacent to rail loading facilities.
Trucking
A number of substantial interstate and intra-state
motor carriers serve Arizona. They, as well as
the railroads, are eager to expand services, and help
develop new industries in Arizona. Hence such
services as new accounting methods to save paper
work by shippers, and arrangements to spot trailers
for loading at shipper's convenience are offered.
Some independent carriers haul stone under ne-gotiated
contract, but common carriers haul ac-cording
to established class or commodity rates.
Below is a sample of present truck rates for stone
42
shipped to the Los Angeles, California, area:
CURRENT COMMODITY RATES FOR
TRUCK SHIPMENT*
COMMODITY: viz: flagstone, gravel, gypsum
rock, lime rock.
TO: Los Angeles, California, area
FROM: Rate
Min.
Wt.
Per
Ton
Per Ton
Miles Mile
Kingman $.51 20,000 $10.20 381 $0.0267
Seligman .51 20,000 10.20 414 .0246
Ashfork .51 20,000 10.20 425 .0240
.43 30,000 8.60 425 .0202
Williams .60 20,000 12.00 445 .0269
.50 30,000 10.00 445 .0224
Flagstaff .68 20,000 13.60 465 .0292
.65 30,000 13.60 465 .0279
Prescott .43 30,000 8.60 372 .0231
Phoenix** .41 20,000 8.00 392 .0204
VII LABOR MARKET
Even a modest growth. of the stone industry in
Arizona implies a need for skilled and semi-skilled
labor. The number presently employed in this field is
not only not known, but is difficult to determine,
because of the many small operations being carried
on at irregular intervals. From a general knowledge
of the production of stone during 1960, it appears
that approximately 200 persons consider the major
portion of their living as being made in stone
production. At least that many again derive some of
their income from stone production, including the
part-time prospector who sells an occasional load,
and the seasonal worker in established quarries.
Many others have some knowledge of stone through
its distribution, sale, and use in construction. Of all
of these, few are considered skilled stone workers.
The industry is new in Arizona, and many of those
who are skilled became so through experience over
the last few years.
In addition to what is considered to be a plen-tiful
general labor market, Arizona's unique climate
is often used to attract specialists in many fields. The
Arizona State Employment Service of the
Employment Security Commission can readily obtain
qualified workers in any field, through the highly
efficient nationwide clearance program; they report
that 30,000 inquiries annually are received from out-of-
state skilled and semi-skilled workers
* Rates as of 2-10-61, shown in Interstate Freight Carriers
Conference, Inc., Local and Joint Freight Tariff No. 1-E,
MFICC No. 7, first revised page 311, items 5620 & 5630.
** Commodity: viz: Building stone, NOI, flagstone, gypsum
rock, lime rock.
desiring to relocate if employment could be pro-vided.
Therefore, any shortage of properly trained
and experienced personnel for the stone industry
should be only temporary.
The ultimate personnel needs of an expanded
stone industry fall into three categories. First, effi-ciency
in production can undoubtedly be in-creased
by skilled quarryman. Even though each rock type
has its own peculiar characteristics to be learned and
mastered, competent stone workers from one part of
the country can readily adapt themselves to a new
type of rock. Second, an expanded stone industry
would presume closely associated milling and
processing, requiring skilled operators of wire saws
and diamond and other rigid saws, and of grinding
and polishing equipment. Third, much of the present
quarry and processing practice requires workers
qualified to operate light and heavy machinery. A
more integrated, mechanized industry would add
further to these requirements.
Arizona's large mining industry could doubt-less
provide many qualified workers for the above
projected needs. Many people in the present stone
industry have mastered the intricacies of particular
rock types. Further personnel needs can be solved
through the national clearance program of labor
placement.
VIII DEPLETION ALLOWANCE, TAXES,
AND INSURANCE
Contrary to popular opinion, tax depletion
allowances are not limited to oil and gas production.
Dimension and ornamental stone, and stone for
aggregate, and road materials are all included in
depletion allowance schedules as well as uranium,
copper, and other minerals. In order to keep pro-ducers
of irreplaceable natural resources on an even
tax basis with manufacturers whose need for de-preciation
(depletion) allowances for capital re-placement
is obvious, Congress has provided that a
certain portion of gross income from a mining or
quarrying operation may be deducted before
calculating taxes. In most industries, the cost of the
capital investment being depleted is known, or can be
evaluated, and a depreciation schedule can be set up
for its replacement. But in mining or quarry-
ing, the reserves of ore or stone are the capital be-ing
depleted; this capital is difficult to evaluate and
to schedule replacement or eventual loss, so the
somewhat arbitrary basis of a percentage of gross
income is used. That is, it is asumed that if a
certain portion of gross income from a property is
not taxed, the money saved will eventually equal
the value of the deposit.
Thus, the following depletion allowances
apply in the stone industry:
Dimension and ornamental stone ....................15%*
Common varieties of stone—including those
sold for concrete aggregate, ballast,
road material, riprap, rubble, or similar
purposes - - - - - - - - - - - - - - - - - - - - - - 5
Inevitably, taxes are an important considera-tion
in any business. Historically, Arizona has been
sympathetic to mining industries, and today con-tinues
to encourage development of its resources.
Taxes facing the stone industry are not excessive.
The most notable assessment is the state-wide sales
tax, as follows:
Wholesale sales tax ...........................................1 %2
Jo
Retail sales tax - - - - - - - - - - - - - - - - - - - - - - -3%
In addition, attention should be drawn to the
requirement for State Industrial Insurance. This
insurance is paid on employees, and the amount
varies according to the job, or type of work, and to
the experience record within an industry.**
IX POTENTIAL
Arizona stone has the potential of being a
well-known, highly desired, and industrially im-portant
construction material. In order to realize
the full potential, people in the stone industry must
recognize the use-position stone is in, relative to
other materials. Then the resources in Arizona, and
the status of the state's present industry must be
evaluated. An expanded and stable stone industry
will develop, if modern production and marketing
methods are diligently applied.
Although concrete block, steel, aluminum, and
glass have replaced stone in some uses, this should
not be looked upon as a crippling blow to the stone
industry. True, heavy structural needs, i.e., founda-
* Not to exceed 50% of net income computed without
allowance for depletion.
** Further general information regarding taxes is avail-able
from the Arizona Development Board and detailed data
are, of course, available from the Arizona State Tax
Commission,
tions and bearing walls, are more efficiently met
by other materials. Also, when rapid construction
is urgent and essential, such as after World War
II, the durability, low maintenance and beauty of
stone may be sacrificed temporarily.
However, excepting these two circumstances,
several factors should combine to create a
rennaissance in the stone industry. First, of
course, the tremendous volume of construction in
the United States has made part of the use of new
materials additional rather than replacement.
Stone is being made to compete in cost with
other materials by standardizing sizes and
shapes, and by volume and integrated production.
Also, architects and designers are abandoning
rigid concepts of stone use, making stone fit
designs rather than designing to fit stone.
Moreover, the very use of new materials
mentioned above, contrives in two ways to
promote use of stone; one, by creating a need for
textural and color relief from the coldness of
manufactured materials, and two, by providing
structural members to support stone work in
circumstances other-wise unfeasible.
Therefore, one may look with optimism to-ward
a steady growth of the stone industry,
roughly parallel to normal construction needs.
Assuming the post-war building gap to be
essentially closed, construction needs should in
turn be parallel to population growth. If, then, the
potential of Arizona's stone industry may be
linked with population growth, the state is indeed
fortunate. Within the optimum transportation
zone, the Pacific South-west, population trends
are awesomely upward. Projections show 3 that
by 1970, five states bordering Arizona (
Colorado excluded) will comprise a 25,000,000
market.
Considering the present status of the stone
industry in Arizona, one may first conclude not
only that the variety of raw material is wide, and
that many unique stones are available, but also
that the reserves are more than ample in most
cases, and almost unlimited in others. Second, one
should freely conclude that as an industry, stone
production in Arizona is in its infancy. Only since
World War II, have population and construction
growth warranted much more production than
would fill local needs.
43
44
How, then, may this burgeoning industry with
ample raw materials realize the indicated
potential? On the basis of study of stone
production problems, mention of some of the
means has been made previously in this text. A
more formal listing of general needs follows.
1 . Volume markets and production
In today's cyclical economy, stability in most
industries is achieved only with large and diversi-fied
markets that are fed by volume production.
Certainly, to be important in the vast construction
industry, Arizona stone must be produced in quan-tities
able to meet needs that arise or that may be
developed. The products may excel in beauty and
durability, but they must also be competitive in
quality, adapatability to construction methods, and
in cost. To some extent, volume demand will in-crease
without stimulation, but it can be hastened
by concerted effort on the part of Arizona stone
producers. Advertising and promotion are
necessary phases of any marketing.* The potential
to business interests and to the State as a whole
justifies increased effort in market creation. With
notable exceptions, producers have concerned
themselves largely with production problems and
quality control. The need for a state-wide trade
association should be considered, state agencies
should be given data by which they can publicize
the industry, and individual producers must plan
for larger sales and promotion programs.
A combination of three rock types may lead
the way toward volume markets. Sandstone, mar-ble,
and tuff all have the potential of meeting most
market demands; all can be produced in large
quantities; all can be cut or split to standardized
dimensions without undue cost; all have a variety
of unique colors and textures. Sandstone is becom-ing
well established, and marble is a traditionally
desirable polished stone. Tuff excels in light
weight, insulation, and ease of cutting, along with
soft colors and textures.
2. Mechanization
If markets are increased. stone producers
must look to mechanization to achieve large
volume production with competitive costs. One of
the most promising mechanical devices not yet
used in Ari-
In this regard, the industry suffers somewhat from lack
of precision in terminology. Architects, designers, and
builders are humanly attracted to materials whose
characteristics they can visualize and measure. This fault
faces all new industries, and can be remedied by cooper-ation
among producers and with users,
zona is the quarry wire saw. Consisting essentially
of a continuous, twisted wire cable run through
pulleys, the saw cuts a groove by carrying abrasive
materials across the stone. Various devices keep
the wire taut, and the groove clean and straight.
Long cuts may be made, and once a cut is started.
little attention is required. Also, as permanent
quarry sites are established, producers may look
to more permanent stone loading and handling
equipment for processing in quarries.
3. Integrated industry
Sandstone is now quarried, hauled, processed,
and marketed by some operators. Other standstone
producers and nearly all other operators perform
only one or two functions. For sufficient profits,
and to remain stable and competitive, it is prob-able
that all dimension stone producers, and cer-tainly
producers of stone to be polished must an-ticipate
performing all functions from quarry to
final sales.
Capital
Without doubt, investment capital is
necessary to implement all other general needs.
Some operators maintain that capital is all that is
needed, but the records show that investment
capital by itself will not necessarily produce the
stability that combined volume markets and
production, mechanization and integration can
produce.
Research and exploration
The organizations and efforts made to create
volume markets, as well as individual producing
firms must contribute to research and exploration.
New techniques are needed in finding deposits, or
in determining the proper quarry sites in known
deposits. Hardly a quarry in Arizona has reached
depths sufficient to know the true nature of un-weathered
or fresh rock. New quarrying techniques
and processing methods may be developed, and
quarry and plant layouts to utilize favorable terrain
are needed. Techniques may be devised for
production of more than one type of stone in a
single processing plant; production of some of the
less produced stone, such as rhyolite, quartzite,
and onyx could possibly be dove-tailed into
production of sandstone, marble, or tuff.
Also research is needed to meet and to help
45
create new trends. Shapes and dimensions must
conform to requirements of steel, concrete, glass
and other materials. Stone producers must work
with producers of pre-cast slabs containing exposed
aggregate, and may even be able to develop pre-fabricated
masonry units; not only the cost of stone,
but the time needed to handle it during construc-tion
must be competitive with other materials.
Colored marble being crushed, screened to size, and bagged for shipment.
46
X GLOSSARY
1. AGGREGATE — The mineral material, such as sand, gravel, shells, slag, or broken
stone, or combinations thereof, with which cement or bituminous material is
mixed to form a mortar or concrete.13
2. ASHLAR — Rectangular blocks having sawed, planed, or rock-faced surfaces,
contrasted with cut blocks which are accurately sized and surface tooled,24 may
be laid in courses.
3. BASALT — A fine-grained, extrusive (volcanic) rock, basic in composition, and
generally dark-colored and hard.
4. BEDDING — Collective term signifying existence of beds or laminae in a rock;
planes dividing sedimentary rocks of the same or different lithology.13
5. BROACH — To drill or cut out material left between closely spaced drill holes.
Also, a mason's sharp pointed chisel for dressing stone.
6. CHANNELING MACHINE — A track-mounted machine operating steel bars in a
chopping action that cuts narrow channels to remove blocks of stone.14
7. CROSS-BEDDING — The arrangement of laminations of strata transverse or
oblique to the main planes of stratification.13
8. CURBING — Slabs and blocks of stone bordering streets, etc.
9. DACITE — A fine-grained, extrusive (volcanic) rock, intermediate in color and
composition between basalt and rhyolite.
10. DOLOMITE — A sedimentary rock composed of carbonate of calcium and
magnesium; resembles limestone.
11. EXPOSED AGGREGATE Phrase applied to the larger pieces of aggregate
purposefully exposed for their color and texture in a cast slab or in concrete or
paving.
12. FIELD STONE —Loose stone scattered by