Coking-Coal Deposits

of the

Western United States

; By PAUL AVERITT

CONTRIBUTIONS TO ECONOMIC GEOLOGY

GEOLOGICAL SURVEY BULLETIN 1222-G

A short summary of the geology 

' and occurrence of coal in 21 

\ localities in 8 Western States

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 25 cents (paper cover)
\ CONTENTS

1 Page.

Abstract___-_-_-________________-___-_-_-_-____-_-____-_-___.__ Gl

* Introduction. __________-_-_-_----_--______-____-______-_-___-_____ 1

Acknowledgments _________________________________________________ 3

Origin, classification, and distribution of coal__________________________ 3

! Properties of coking coal_-_-__-_-----_--__-_-_--__-_-___---_______- 5

Uses and properties of coke-__--____________--_--___________________ 6

Blast-furnace coke__---_------------------------_-_---_-------- 6

Foundry coke--___----_-_---_-------------------_-------_---_- 7

* Coking-coal deposits___^__-__-___---__---__-----____-__--______--_- 7

Washington_________________________________________________ 10

Wilkeson-Carbonado field and Fairfax-Montezuma area, Pierce

County, Wash_________.__________________ 10

Roslyn field, Kittitas County, Wash._____________________ 12

i Montana.____________________________________________________ 14

Livingston field, Park and Gallatin Counties, Mont__________ 14

Electric field, Park County, Mont.__________________________ 16

Great Falls field, Cascade and Judith Basin Counties, Mont____ 17

Wyoming__ _________________________________________________ 18

Kemmerer-Willow Creek field, Lincoln County, Wyo_________ 19

Rock Springs field, Sweetwater County, Wyo _________________ 21

; Cambria field, Weston County, Wyo_________________________ 22

^ Utah__________-.________________________ 23

Sunnyside-Castlegate field, Carbon County, Utah _____________ 23

Mount Pleasant field, Sanpete County, Utah_______________ 25

Kolob field, Iron, Washington, and Kane Counties, Utah_______ 26

Colorado. _._______.____..___________^____.__ 27

; Somerset-Crested Butte-Carbondale region, Delta, Gunnison, and

Pitkin Counties, Colo_______-__________________._____ 27

Somerset field, Coal Creek district_______________________ 28

, Crested Butte field. __ __________________ ___ 29

Carbondaie field__________________________ 29

v San Juan River field, Montrose, San Miguel, Dolores, and Montezuma Counties, Colo____________________________.________ 30

y. Durango field, La Plata County, Colo______________________ 30

Raton Mesa region, Huerfano and Las Animas Counties, Colo.,

\ and Colfax County, N. Mex____________________ 32

New Mexico______-__________________-___.____________________ 33

] Monero field, Rio Arriba County, N. Mex____________________ 34

Cerrillos field, Santa Fe County, N. Mex.____________________ 35

* Carthage field, Socorro County, N. Mex__________________ 35

^ Oklahoma and Arkansas______________________________________ 36

Henryetta district, Okmulgee County, Okla_________________ 36

Southern part of the Oklahoma field, Coal, Pittsburg, Atoka,

Latimer, and LeFlore Counties..__________________________ 38

Western Arkansas field, Sebastian, Crawford, Franklin, Logan,

Scott, Johnson, Pope, and Yell Counties_________________ 41

" * Conclusion__ ______________________________________'_____________ 42

Selected bibliography______________________________________________ 43

\

m
IV CONTENTS

ILLUSTKATION

Page 

FIGURE 1. Map of coal fields of the conterminous United States west of

the Mississippi River showing coking-coal localities _________ G2

TABLE

Page

TABLE 1. Classification of coals by rank__ _____ ____ G4 /
CONTRIBUTIONS TO ECONOMIC GEOLOGY

COKING-COAL DEPOSITS OF THE WESTERN 

UNITED STATES

By PAUL AVERITT

ABSTRACT

Twenty-one areas in eight Western States yield coal of varying degree of utility in the manufacture of coke. The geology and coal resources of each of these 

areas is summarized briefly. Three of these areas the Raton Mesa region, 

Colorado and New Mexico, the Carbondale field, Colorado, and the SunnysideCastlegate field, Utah are important sources of metallurgical coke used by the 

growing western steel industry. Some of this western-made metallurgical coke 

is upgraded by the addition of small amounts of low-volatile bituminous coal 

from the southeastern Oklahoma and Arkansas fields.

Several other fields, notably the Wilkeson-Carbonado-Fairfax and the Roslyn 

fields, Washington, and the Kemmerer-Willow Creek field, Wyoming, contain adequate resources of coal that by washing and blending can be made to yield coke 

approaching in quality that made from coal obtained in the producing fields.

Other areas yield coal suitable for the manufacture of lower grade coke, 

formerly used in nonferrous smelting, and used at present in the recovery of 

elemental phosphorus and in the refining of sugar. Other areas are undeveloped.

INTRODUCTION

The U.S. Geological Survey and various State agencies have mapped 

the geology and studied the coal resources of the United States for 

many years. The U.S. Bureau of Mines and other agencies have been 

engaged in sampling, analysis, and technologic studies of coals, which 

complement the geologic and resource studies. Of the great bulk of 

accumulated data, the part applicable to coking coals in the Western 

United States is widely scattered in the geologic and technologic literature, and many older reports of great value are out of print.

This report is, therefore, intended to consolidate and to summarize 

very briefly information pertinent to coal in 21 localities in the Western 

United States (see fig. 1) where the coal has coking properties and to 

provide a selected list of publications describing the coal in these localiGi
G2 CONTRIBUTIONS TO ECONOMIC GEOLOGY

ties. Although emphasis is placed on the geology and resources of 

coal, publications concerned with the technologic aspects of coking 

coal are cited to complete the summary.

Anthracite and 

semianthracite

Medium- and high-volatile Subbituminous coal 

bituminous coal

Lignite

1. Wilkeson-Carbonado field and 

Fairfax-Mohtezuma area.

2. Roslyn field.

3. Livingston field.

4. Electric field,

5. Great Falls field.

6. Kemmerer-Willow Creek field.

7. Rock Springs field.

8. Cambria field.

9. Sunnyside-Castlegate field.

10. Mount Pleasant field.

11. Kolob field.

12. Somerset-Crested Butte-Carbondale region.

13. San Juan River field.

14. Durango field.

15. Baton Mesa region.

16. Monero field.

17. Cerrillos field.

18. Carthage field.

19. Henryetta district.

20. Southern part of the Oklahoma field.

21. Western Arkansas field.

FIGURE 1. Coal fields of the conterminous United States west of the Mississippi 

River showing coking-coal localities.
COKING-COAL DEPOSITS, WESTERN UNITED STATES G3 

ACKNOWLEDGMENTS

This report is a revision of an earlier report by L. R Berryhill and 

Paul Averitt (1951) and incorporates much information used in that 

report. Paragraphs on specific areas and fields have been reviewed, 

updated, or rewritten by individuals familiar with those areas. These 

contributors include H. M. Beikman and H. D. Gower (Washington),' 

A. E. Roberts (Livingston field, Montana), G. D. Fraser (Electric 

field, Montana), R. B,. Johnson (New Mexico and Raton Mesa field, 

Colorado), J. R Donnell (Carbondale field, Colorado), W. J. Mapel 

(Cambria field, Wyoming), and B. R. Haley (Oklahoma and 

Arkansas).

ORIGIN, CLASSIFICATION, AND DISTRIBUTION

OF COAL

Coal is composed of ancient plants and plant fragments that accumulated in former marshes and swamps. As this material increased 

in quantity year after year in the swampy environment, the lower 

layers were compacted under the weight of the upper layers and, in 

time, became peat, the initial stage in the formation of coal. Later, 

the swamps were flooded by the sea and buried under vast accumulations of sand and silt washed in by streams flowing from nearby lands. 

The layers of peat thus became further compressed under the weight 

of these sediments. Pressure and heat from movements of the earth's 

crust aided locally in the process of compaction and coalification, which 

has been going on slowly and continuously for a long period of geologic time.

During the process of compaction and coalification, the beds of coal 

undergo a series of physical and chemical changes that, in general, 

result in a reduction in moisture and volatile matter and a corresponding increase in fixed carbon, and heat value. The change a coal has 

undergone, as measured by variations in these components, is the basis 

for the established classification of coal by rank. The terms "lignite," 

"subbituminous coal," "bituminous coal," and "anthracite" thus 

describe stages in the coal-forming process. Each of these major ranks 

of coal is further subdivided on the basis of chemical properties. 

Table 1 shows the classification used in the United States.

More than half of the coal used in the manufacture of coke is of 

high-volatile A bituminous rank, followed, in order of use, by coal of 

low-volatile and medium-volatile bituminous ranks.

Coal-bearing rocks are widely distributed west of the Mississippi 

River, as shown in figure 1. On a simple tonnage basis, this area 

contains 70 percent of the total coal resources of the United States.
TABLE 1. Classification of coals by rank 1 

[Adapted from American Society for Testing Materials, 19

Class

III. Subbituminous____

Group

1. Meta-anthracite _ __

1. Low- volatile bituminous 

coal. 

2. Medium-volatile bituminous coal. 

3. High-volatile A bituminous coal. 

4. High-volatile B bituminous coal. 

5. High-volatile C bituminous coal.

2. Lignite B _ __.___._ _

Limits of fixed carbon, 

dry, mineral-matterfree basis (percent)

Equal or 

greater 

than 

98 

92 

86 

78

69

Less 

than 

98 

92 

86

78 

69

Limits of volatil

matter, dry, miner

matter-free basis 

(percent)

Equal or 

greater 

than 

2 

8 

14

22 

31

Les

than 

1 This classification does not include a few coals, principally nonbanded varieties, 

which have unusual physical and chemical properties and which come within the limits 

of fixed carbon or calorific value of the high-volatile bituminous and subbituminous 

ranks. All of these coals either contain less than 48 percent dry, mineral-matter-free 

fixed carbon or have more than 15,500 moist, mineral-matter-free Btu per pound.

2 "Moist" refers to coal containing its natural inherent moisture but not including visible water on the surface of the coal.

3 If agglomerating, class

4 Coals having 69 percen

shall be classified accordin

6 It is recognized that th

bituminous class, and ther
COKING-COAL DEPOSITS, WESTERN UNITED STATES G5

Most of the western coals are of lignitic, subbituminous, and highvolatile C and B bituminous ranks and 'are generally unsuitable for 

the manufacture of coke. By contrast, the area east of the Mississippi River contains 30 percent of the total United States resources, 

all of which is of bituminous or anthracitic rank, and much of which 

can be used in the manufacture of coke. This geographic distribution 

of high- and low-rank coal is due in part to differences in age. Coal 

east of the Mississippi Eiver, and in Iowa, Kansas, Missouri, Oklahoma, Arkansas, and parts of Texas, is of Pennsylvanian age, whereas 

coal in the Rocky Mountain and Pacific coast regions is of Cretaceous 

or Tertiary age. The younger coal in the West has reached bituminous 

or higher rank only in areas of mountain building and igneous activity, 

as locally in Montana, Wyoming, Colorado, New Mexico, Utah, and 

Washington.

The best metallurgical coke is made from high-volatile A or mediumvolatile bituminous coal or from blends of high- and low-volatile bituminous coal. Although the West possesses comparatively small resources of coal of these ranks suitable for manufacturing coke, 21 

localities contain coal that will coke to some degree. Several of these 

localities produce most of the coal used in the western steel industry. 

The growing industrialization of the West and the accompanying increase in energy consumption thus emphasize the desirability of more 

knowledge of western coking-coal resources.

PROPERTIES OF COKING COAL

Coke is a hard cellular mass of carbon and inert ingredients prepared from certain kinds of coal that fuse or become semiliquid during 

destructive distillation. Once formed, coke is infusible, rather friable, 

and porous and has a metallic gray luster. Many bituminous coals will 

coke or fuse when heated in a closed furnace, but only those that produce coke within the specific range of chemical and physical properties suitable for metallurgical and other industrial uses can be considered coking coals.

Standards have not yet been devised for the identification of a good 

coking coal by its chemical composition or physical properties. Rank 

is not the only criterion, for many coals of suitable rank have poor 

coking qualities. It must be concluded, therefore, that the original 

composition of the bed is an important factor in determining coking 

properties. Certain ingredients of coal influence coking properties. 

Most bituminous coals, for example, contain bright, vitreous bands 

known as vitrain, which represents the coalified trunks and limbs of 

plants. The most strongly coking ingredients occur within the vitrain 

bands, which are abundant in good coking coals. Fusain, the ingre799-641 66 2
Go CONTRIBUTIONS TO ECONOMIC GEOLOGY

dient making up the dull, porous, and friable bands in coal, will not 

coke and, if present in large quantities, renders a coal useless for the 

manufacture of coke.

Other factors being equal, coal having an oxygen content of less than 

about 10 percent will coke, and coal having more than 10 percent will 

not coke. Excessive hydrogen also has been shown to decrease the 

coke yield.

A good coking coal, when subjected to a gradually increasing temperature, fuses or softens generally between 572° and 752° F. Gases of 

decomposition that form at the fusing temperature, or slightly higher, 

cause the mass to become cellular and swollen. Viscosity increases with 

increased temperature until the mass becomes practically rigid as the 

temperature of 842° F is approached. Changes in structure continue, 

because of devolatilization, even after the coke has reached red heat, 

and the evolution of gases continues long after the mass has become 

rigid (Rose, 1927, p. 601-602). Noncoking coals will not fuse or become pasty when heated. The fused cellular structure is a unique 

characteristic of coke that distinguishes it from charcoal and from 

chars formed from infusible or noncoking coals. The coking qualities 

of most coals can be improved by washing to remove ash and sulfur, 

or by processing to remove noncoking components. An excellent coke 

may sometimes be obtained by blending two coals having somewhat 

different properties, although neither of the coals alone would produce 

a satisfactory coke. Similarly, blends employing a poorly coking coal 

as the base stock may include small amounts of noncoking ingredients, 

such as anthracite fines, petroleum coke, or low-temperature char, 

which greatly improve the qualities of the resulting coke. Natural 

coke may be produced under favorable geologic circumstances in coal 

beds penetrated or affected by igneous intrusions.

USES AND PROPERTIES OF COKE

Coke is used primarily in blast furnaces for the reduction of iron 

ore and in foundries as a source of heat to melt metal. Other minor uses 

include the production of elemental phosphorus by the electric-furnace 

method, the refining of sugar, space heating, and the manufacture of 

water gas. (See Sheridan and De Carlo, 1965, p. 27.) Specifications 

for coke vary, therefore, according to the intended use. In general, 

physical characteristics and included impurities, such as ash, sulfur, 

and phosphorus, are the most important factors.

BLAST-FURNACE COKE

Specifications are most rigid for coke that is used in the blast furnace, where it must have strength adequate to support the charge and
COKING-COAL DEPOSITS, WESTERN UNITED STATES G7

must supply carbon monoxide for reducing the ore, as well as heat to 

melt the metal. Most blast-furnace coke is used in iron smelting, and 

for this purpose the requirements are as follows (Eose, 1927, p. 631- 

636;Davis,1942,p.2-7):

Maximum 

percentages

Ash (less than 10 percent desirable) _ 8-16

Sulfur ____________________________________ 1.3

Phosphorus (for acid Bessemer iron)._____________________ .01

In addition, the coke should be of medium density, and the individual 

pieces should range from 2 to 4 inches in diameter.

Standards of strength and ash content are lower for coke used in 

nonferrous smelting in a blast furnace. A large and increasing proportion of nonferrous ore, however, comes to the smelter as finely 

ground concentrate that is more easily handled in a reverberatory furnace, which requires no coke. Since 1910 the blast furnace has been 

largely replaced by the reverberatory furnace in copper smelting.

FOUNDRY COKE

Foundry coke provides only heat to melt metal, and for this purpose 

the chief requirements are purity, large size, good strength, and a 

minimum reactivity with carbon dioxide gas. :

Other users of coke have specifications that generally can be met only 

by use of certain coals or blends of coal in the coke manufacturing 

process. Experience in wartime and in areas with limited coal resources has shown, however, that by blending coals, chars, and other 

ingredients and by adopting special metallurgical processes, coal of 

inferior quality can be used in the manufacture of coke that will be 

satisfactory for many purposes, including the production of iron and 

steel. The selection of a coal for coking is, therefore, determined in 

part by economic considerations. In the Western United States, the 

cost of shipping eastern coal is weighed against the cost of cleaning, 

blending, and using local coal.

COKING-COAL, DEPOSITS

The expansion of manufacturing and industry in the West during 

and after World War II has increased the need for local coal that will 

serve for coking and allied purposes. At several localities the western 

high-volatile bituminous coal will form a coke that is satisfactory for 

use in blast furnaces and foundries. It is, however, inferior in porosity, 

size, and strength to the coke produced from eastern coal. At other 

localities in the West the potential of the coal in the manufacture of 

coke depends in part upon improvements in processing and coking
G8 CONTRIBUTIONS TO ECONOMIC GEOLOGY

practices, or on special adaptions of metallurgical processes. A few 

other areas contain coal with coking properties, but these areas are 

considered to be of minor economic importance because of impurity 

of the coal, difficult mining conditions, or limited resources.

The important coking-coal localities in the West are the Raton Mesa 

region in Colorado-New Mexico, the Sunnyside-Castlegate field in 

Utah, the Somerset-Crested Butte-Carbondale region in Colorado, and 

the coal fields in southeastern Oklahoma and western Arkansas. The 

highest quality western coke, satisfactory for all metallurgical purposes, is made from coal from the Eaton Mesa region blended with 

small amounts of low-volatile coal. Coal from this field serves the coke 

plant and steel mills of the Colorado Fuel and Iron Corp. at Pueblo, 

Colo., but it is relatively remote from other centers of western iron 

and steel production and consumption, and more general use of the 

coal is restricted by transportation costs.

The coal from the Sunnyside-Castlegate field, Utah, is notable because it produces a borderline coke that is used successfully in blast 

furnaces for the smelting of iron though the coke is brittle and contains too high a percentage of small sizes. As a result, it has become 

the minimal standard by which the coking properties of high-volatile 

western coal are judged. The Sunnyside-Castlegate field supplies most 

of the industrial coking-coal needs of Utah, and because of its location 

west of the Rocky Mountains, it is the source of much of the coke used 

on the west coast.

The coal in the Carbondale field, Pitkin County, Colo., has long been 

known for its excellent coking properties. Since 1953 it has been 

mined for shipment to the Geneva plant of the United States Steel 

Corp., near Provo, Utah.

Most of the other deposits of coking coal in the West are no longer 

mined as sources of metallurgical coke though, in the past, coal from 

many of these areas was coked in beehive ovens and used in nonferrous 

smelters and refineries. With more restrictive specifications and improvements in transportation, however, the superior cokes made from 

eastern coal and from the coal produced in the Raton Mesa region, the 

Sunnyside-Castlegate field, and the Somerset-Crested Butte-Carbondale region in the West were able to compete directly with the local 

products.

The growing western iron and steel industry would be greatly benefited, if coal from some of the more advantageously located cokingcoal deposits, of which the Washington coal deposits are an excellent 

example, could be utilized for metallurgical purposes. Such use might 

entail both cleaning and blending of the local coal with a low-volatile 

char, but even with the added processing costs the utilization of the
COKING-COAL DEPOSITS, WESTERN UNITED STATES G9

local coal might eventually prove to be more economical than shipping and processing coal from distant sources.

Another avenue of investigation that deserves and has received much 

attention is the development of practical methods of producing lowvolatile char and coke from lower rank coal. During the period 1961- 

63, the Food Machinery & Chemical Corp. and the United States Steel 

Corp. operated an experimental plant at Kemmerer, Wyo., designed 

to produce metallurgical coke from subbituminous coal. Several thousand tons of coke briquettes were produced annually during the period 

and were tested in iron blast furnaces and in electric furnaces for the 

recovery of elemental phosphorus. The tests were reported to be successful. The plant was placed on a standby basis in July 1963 (U.S. 

Bur. Mines, 1964a, p. 1212). Other similar experiments have been reported by the U.S. Bureau of Mines (1964c) and by Berg (1962).

Because many economic and technologic factors are involved in 

the specification for a coking coal, no simple field or laboratory test 

will measure the coking quality of a coal in absolute terms. On 

the basis of available information, therefore, it is difficult to delimit 

adequately the areas of coking coal in the Western States or to make 

completely satisfactory estimates of resources of coking coal. Figure 

1, however, shows 21 localities in the West where coal having coking 

properties has been obtained. In paragraphs following, the available 

information regarding the occurrence of coal at each locality, the 

properties of the coke produced, and the resources of coal are summarized very briefly.

In discussion of resources of coal, the terms "measured," "indicated," 

and "inferred" are used to distinguish three classes of coal according 

to the abundance and reliability of the data on which the estimates are 

based. Measured resources are based on observations about one-half 

mile apart, or which lie within one-half mile of a well-defined continuous outcrop. Indicated resources are based on observations about 

1-1 y2 miles apart, or which lie no more than 2 miles from a welldefined continuous outcrop. Inferred resources are based on broad 

knowledge of the geologic character of the coal beds and may be supported by few observations. In general, coal classed as inferred lies 

more than 2 miles from the outcrop.

In reporting tonnages of coal resources, the term "original resources" 

refers to resources in the ground before mining began. "Remaining 

resources" are unmined resources in the ground as of the date of the 

appraisal. Where this term is used, past production and losses have 

been subtracted from the estimated original resources, but no allowance has been made for future losses. Where allowance has been made 

for past production and losses and for future losses, the term "recoverable resources" is used.
GlO CONTRIBUTIONS TO ECONOMIC GEOLOGY

WASHINGTON

The important deposits of coking coal in Washington are in the 

Wilkeson-Carbonado field and the Fairf ax-Montezuma area in Pierce 

County, on the western slope of the Cascade Range, and in the Roslyn 

field in Kittitas County, on the eastern slope of the Cascade Eange. 

Other deposits of coal that may be of coking quality, but that have 

not yet been adequately tested, extend along the western slope of the 

Cascade Range from eastern Lewis County, through the Ashford 

urea in southern Pierce County, and into King, Skagit, and Whatcom 

Counties, nearly to the northern boundary of the State (Warren and 

others, 1945; Vine, 1962; Gower and Wanek, 1963; Jenkins, 1923, 

1924).

Much information on coking properties of coal in Washington is 

contained in reports by Daniels (1941), Davis and others (1942), 

Marshall and Bird (1931), Reynolds and others (1946), and Yancey 

and others (1939, 1943). A summary of the history of coke production, the rank and quality of the coking coal, and brief descriptions 

of coking-coal areas are included in a report on the coal reserves of 

the State (Beikman and others, 1961).

The coking properties of the coal in Washington, except for coal 

in the Roslyn field, are related primarily to an increase in rank caused 

by the close folding of the sedimentary rocks containing the coal 

beds. Other factors that may affect the rank and hence the coking 

properties of coal are age and depth of burial. The stratigraphically 

lower coals those that are older and have been more deeply buried 

have a higher rank in places.

In the Roslyn field, coal suitable for coking occurs only in the 

northwestern part of the field, although the amount of structural 

deformation is about the same everywhere. The coking properties 

are therefore attributed to differences in composition of the original 

coal-forming materials and to a local increase in rank that is due 

possibly to the heat of a nearby igneous intrusive.

WILKESON-CARBONADO FIELD AND FAIRF AX-MONTEZUMA AREA, 

PIERCE COUNTY, WASH.

Most of the coking coal produced on the Pacific coast has been obtained from the Wilkeson-Carbonado field and from the Fairf axMontezuma area in Pierce County, Wash. (fig. 1, loc. 1; Daniels, 1914). 

Many coal beds of varied extent and thickness are present in these 

areas. In the Wilkeson-Carbonado field, there are nine beds more 

than 2!/£ feet thick, and in the Fairf ax-Montezuma area there are six 

beds more than 2!/£ feet thick (Beikman and others, 1961). Additional beds may be present in both areas. The coal beds are confined 

to a north-south trending belt 3-6 miles wide near the center of the
COKING-COAL DEPOSITS, WESTERN UNITED STATES Gil

county. On both, the east and west sides of the belt, the coal-bearing 

rocks dip beneath volcanic rocks of Tertiary age.

The coal beds in Pierce County are in the Puget Group of Eocene 

age, a sequence of interbedded sandstone and shale 10,000-15,000 feet 

thick. The Puget Group in this area is divided into three formations, 

the oldest of which, the Carbonado Formation, contains most of the 

important coal beds. The Wilkeson Formation, a sequence made up 

dominantly of sandstone overlying the Carbonado, is barren. The 

still younger Burnett Formation includes only a few beds of commercial value, which yield coal of lower quality than the coal from the 

Carbonado Formation.

The principal structural features of the Wikeson-Carbonado field 

and the Fairfax-Montezuma area are tightly folded anticlines and 

synclines, the limbs of which commonly dip more than 60°. The 

strata involved in these folds have been broken by many normal and 

high-angle reverse faults. Displacements on these faults range from 

a few feet to more than 1,500 feet. The structure of the coal field is 

further complicated by intrusive igneous rock, the heat from which 

has altered the adjoining sedimentary rocks and coal beds.

The coal ranges widely in rank according to the amount of deformation or alteration it has undergone, and analyses on the as-received 

basis range in general as follows (Daniels, 1941, p. 16):

Range in composition

(percent)

Moisture_________ 4. 0- 2. 0 

Volatile matter_____ 33. 0-20. 0 

Fixed carbon______ 51. 0-63. 0

Range in composition

(percent)

Ash________________ 12. 0-15. 0 

Sulfur______________ .6- .8 

Phosphorus__________ .05- .1

According to Daniels (1941, p. 62), Pierce County coals can be 

coked successfully in byproduct ovens and with careful blending will 

yield a coke that can be used for most purposes. Coke manufactured 

during the period 1915-34 ranged from 12.7 to 26.6 percent in ash 

content and from 0.25 to 1.65 percent in sulfur content. The higher 

figures are extreme, however, and can be reduced by washing and 

selective blending of the coal. Tests conducted by the U.S. Bureau 

of Mines, utilizing coal from the No. 2 bed near Wilkeson blended 

with 25 percent petroleum coke, yielded coke having the following 

properties (Yancey and others, 1943) :

Phosphorus____percent__ 0.69

Sulfur _________do__ .5

Cell space ______do__ 55.2

Coke yield_______do__ 72.1

Apparent specific gravity- 0.87 

True specific gravity___ 1.94 

Ash-softening temperature

°F ____________ 2, 800+ 

Btu _____________ 12,620 

Moisture _____percent_ 1. 0 

Volatile matter__do__ . 8 

Fixed carbon___do__ 87.0 

Ash _______do__ 11.2

Tumbler and shatter tests: satisfactory 

for electrochemical and electrometallurgical purposes, questionable for 

foundry and iron blast furnace.
G12 CONTRIBUTIONS TO ECONOMIC GEOLOGY

The estimated remaining resources of coal in the Wilkeson-Carbonado field, in beds 14 inches or more thick and less than 3,000 feet 

below the surface, total 222 million tons. Of this total, 78 million tons 

is in beds 42 inches or more thick and less than 1,000 feet below the 

surface (Beikman and others, 1961, p. 81-82). The estimated resources in the Fairfax-Montezuma area, calculated on the same basis, 

total 21 million tons, of which most is in thinner beds (Beikman and 

others, 1961, p. 84-85). Much of the tonnage in these two areas is 

coking coal; however, the coking properties of all coal beds have not 

been adequately tested.

In the nearby Spiketon, Melmont, and Ashford areas, which are 

structurally separated from each other and from the Wilkeson-Carbonado and Fairfax-Montezuma areas, the combined estimated resources in beds 14 inches or more thick and less than 3,000 feet below 

the surface total 119 million tons. Of this total, 26 million tons is in 

beds 42 inches or more thick and less than 1,000 feet below the surface 

(Beikman and others, 1961, p. 82, 83, 85). Part of this total is also 

coking coal.

ROSLYN FIEHJ>, KITTITAS COUNTY, WASH.

The Koslyn field in Kittitas County, Wash. (fig. 1, loc. 2), which 

has been described by Saunders (1914) and by Beikman and others 

(1961), covers an area of about 30 square miles on the east slope of 

the Cascade Range, approximately 75 miles east of Tacoma. The 

Roslyn field, though small, has produced more coal than any other area 

in the State. The coal beds are confined to the upper 1,560 feet of 

the Roslyn Formation, a 6,500-foot-thick sequence of sandstone and 

shale of Eocene age. This upper zone includes eight major coal beds 

ranging in thickness from less than 2 feet to 21 feet. Of these eight 

coal beds, five have been mined, but the Roslyn (No. 5) and Big Dirty 

(No. 1) are the most important.

The Roslyn (No. 5) coal bed, which has been mined most extensively, ranges in thickness from about 4.5 to 7 feet and contains an 

average of 4.4 feet of clean coal. The bed is relatively uniform in 

thickness and has been mined throughout the entire area of the field. 

The Big Dirty (No. 1) coal bed, so named because it is 15-19 feet 

thick and high in ash, is the uppermost bed in the field and second in 

economic importance. Only the lower part of the Big Dirty, which 

contains an average of 4.6 feet of coal, is sufficiently clean to be minable. Much less is known about the remaining three coal beds that 

have been mined. The Plant (No. 6) bed is about 2.9 feet thick and 

about 410 feet below the Roslyn bed; the Green (No. 7) bed is about 

1.8 feet thick and about 90 feet below the Plant bed; and the Wright
COKING-COAL DEPOSITS, WESTERN UNITED STATES G13

(No. 8) bed, the lowest in the stratigraphic sequence, is 3.0 feet thick 

and 150 feet below the Green bed.

The coal-bearing sedimentary rocks in the Roslyn field dip toward 

the center of a gentle southeastward-plunging syncline at angles of 

10°-30°. In general, the structure is simple and presents no obstacle 

to mining. The structure along the southwest margin of the field is 

more complex and consists of a series of anticlines that trend parallel 

to the major syncline. Local variations in the dip and thickness of 

the beds, known as "faults" by the miners, are actually rolls or warpings that have thickened or thinned the coal. For the most part these 

do not interfere seriously with mining. The Roslyn Formation is underlain by the Eocene Teanaway Basalt and overlain by the Miocene 

and Pliocene Yakima Basalt.

Coal suitable for coking occurs only in the northwestern part of 

the Roslyn field. The increase in coking properties of the coal in the 

Roslyn bed, from the southeast to the northwest, is related to differences in composition and a change in rank. Differences in composition are indicated by a gradual increase to the northwest in the agglutinating value of the coal and by a decrease in the ash content. The 

rank and Btu value of coal in the Roslyn bed also increase gradually 

to the northwest. Changes similar to these observed in the Roslyn 

bed may occur in other coal beds in the field, but this cannot be substantiated because available analyses of the other beds are confined 

to samples from the northwestern end of the field.

The change in rank of the Roslyn coal bed may have been caused in 

part by heat from a nearby intrusive body. This possibility is suggested by the presence of a granodiorite exposure 6 miles northeast of 

the Roslyn field.

The coal from the Roslyn field is of high-volatile A bituminous rank. 

An analysis, on the as-received basis, of a composite sample of coal 

from the Roslyn bed taken from three locations within the Roslyn 

No. 3 mine at Ronald, Kittitas County, is as follows (U.S. Bur. Mines, 

1941, p. 42-43):

Percent

Moisture __________ 3.5 

Volatile matter_______ 37. 8 

Fixed carbon_________ 46. 7 

Ash ______________ 12.0 

Sulfur ____________ . 3

Percent 

Air-drying loss__________ 1. 6

Btu_________________ 12, 630

Average phosphorus content of four 

samples of coal from the Roslyn bed 

0.66 percent (Yancey and others, 1943, 

P. 8).

Tests by the U.S. Bureau of Mines (Yancey and others, 1943), indicated that coke made from 100 percent Roslyn coal is somewhat

799-641 '66-
G14 CONTRIBUTIONS TO ECONOMIC GEOLOGY

fingery as compared with coke manufactured from coal produced in 

Pierce County or with coke manufactured from blends of Eoslyn and 

Pierce County coal and petroleum coke. Furthermore, it tends to be 

weak in shatter and tumbler tests and to have a high phosphorus content. Koslyn coal forms excellent coke for domestic use, however, 

and is satisfactory for use in coking-coal blends.

The estimated remaining resources of coal in the Koslyn field, based 

on exploration and mapping as of January 1, 1960, total 241 million 

tons. Only part of this total lies in the more favorable northwestern 

part of the field. The Roslyn bed contains 54 million tons, of which 

28 million tons is in a part of the bed 42 inches or more thick and 

less than 1,000 feet below the surface (Beikman and others, 1961, p. 

32-33). The Roslyn bed is the only bed in the field known to have 

coking properties, although other coal beds as yet untested may have 

similar properties.

MONTANA

Although Montana has large resources of coal, only three areas in 

the central part of the State contain coal with coking properties. In 

the Livingston field, Gallatin and Park Counties, and in the Electric 

field, southern Park County, the sedimentary rocks have been tightly 

folded and faulted and, as a result, part of the coal has coking properties. In the Great Falls field, Cascade and Judith Basin Counties, 

the rocks are nearly horizontal and no alteration of the coal by earth 

movements or igneous activity has taken place.

Coal from these three Montana fields was formerly used in the 

production of coke for local copper smelters. With the introduction 

of the reverberatory furnace and the basic copper converter in the 

early 1900's, coke was no longer needed in quantity. Because coke 

made from Montana coal is not of sufficiently high quality for use in 

other metallurgical processes without the adoption of special methods, 

the local coke manufacturing industry closed down about 1912. No 

coke has been manufactured in Montana since that date. Information on the past production of coke in Montana is contained in "Mineral Resources of the United States" (U.S. Geol. Survey, 1883-1916), 

in annual reports of the Montana Inspector of Mines (1890-1912), 

and in a report by Roberts (1966).

LIVINGSTON FIELD, PARK AND GALLATIN COUNTIES, MONT.

The Livingston coal field is a narrow, Y-shaped belt of deformed 

rocks covering an area of about 35 square miles between Bozeman and 

Livingston, Mont. (fig. 1, loc. 3). The area has been mapped in detail by Roberts (1957, 1964a-h). The coal beds in the Livingston 

field are concentrated in two well-defined and persistent carbonaceous
COKING-COAL DEPOSITS, WESTERN UNITED STATES G15

zones in the Eagle Sandstone of Late Cretaceous age. In each zone 

the coal beds range in thickness from a few inches to more than 10 

feet but average 3-4 feet. The variations in thickness are due in part 

to differences in the nature of the original carbonaceous deposits and 

in part to later tectonic movements. The individual beds typically 

contain several partings of shale, clay, or impure coal.

The coal-bearing rocks have been compressed into three major enechelon folds, which are partly overturned and overthrust, and are 

further disturbed by subordinate thrust faults, normal faults, and 

tension cracks. Erosion of these folds has left the coal-bearing rocks 

in narrow belts along the flanks of anticlines and in the intervening 

synclines. The coal beds generally dip 40°-50°, and in several localities they are overturned.

The coal in the Livingston field is of high-volatile A, B, and C 

bituminous ranks. The localities that yielded the best coking coal 

are along the flanks of anticlines. Coal in synclines and in the 

plunging ends of anticlines either made poor coke or would not coke. 

The synclines are more tightly compressed than the anticlines, and 

the plunging ends of anticlines are much more faulted than the flanks. 

Thus, coal with the strongest coking properties is found in areas of 

apparently less tectonic disturbance.

An analysis, on the as-received basis, of coking coal from a selected 

37-inch part of the Cokedale bed at the Hodson mine is as follows 

(Calvert, 1912a, p. 402):

Percent 

Moisture ________ 5. 8

Volatile matter_______ 33.1

Fixed carbon- _ 50. 5 

Ash ______________ 10. 57

Percent

Sulfur ________.______ 0.50 

Air-drying loss_ .._____ 3. 8

Btu _________ ____. ______ 12, 280

Coal from the Livingston field was used to manufacture coke between the early 1880's and 1896 and again in the early 1900's. During 

the period of maximum coke production in the 1890's, about 115 

beehive ovens were in operation at Cokedale. Nearby, at the town of 

Storrs, there were 100 finished and 100 unfinished ovens, but these 

were used only for experimental tests (Eowe, 1906, p. 77).

Most of past mining in the field has been concentrated in the 

Cokedale bed, which has the strongest coking properties. According 

to Roberts (1966), the remaining resources in the Cokedale bed in 

parts of the bed 28 inches or more thick and less than 1,000 feet 

below the surface totaled 21 million tons as of January 1,1965. The 

distribution of resources in other parts of the Cokedale bed, and in 

other beds in the field, is presented in the Roberts report by townships, 

beds, thickness of coal, amount of overburden, and other resource 

categories.
G16 CONTRIBUTIONS TO ECONOMIC GEOLOGY 

BjLiECTKIC FIEU>, PARK COUNTY, MONT.

Coal has been mined for the production of coke in three structurally 

separated parts of the Electric field (fig. 1, loc. 4), which together 

compose an area of less than 3 square miles. Mining and coke manufacturing were carried out in this area between 1894 and about 1912, 

but the mines have been closed and the ovens abandoned since that 

time. The coal is in the Eagle Sandstone of Late Cretaceous age 

in a 300-foot sequence of shale and sandstone overlying the Virgelle 

Sandstone Member, which in this area is the conspicuous basal member 

of the Eagle. Of the three coal beds noted by Calvert (1912b) only 

the upper or No. 1 coal, about 300 feet above the Virgelle, has been 

mined extensively. The No. 1 coal occurs as local lenses within a 

thicker carbonaceous sequence; hence stratigraphic position, thickness, 

and purity of the coal are highly variable. At most localities, however, the coal is l%-5 feet thick, including clay and sandstone partings, 

and it averages about 3 feet. The No. 2 and 3 coals, approximately 

100 feet and 50 feet, respectively, above the Virgelle, though locally 

as thick as the No. 1, were not mined when the field was active, apparently because they were generally too thin, deep, discontinuous, 

or impure, or did not coke well enough.

Mining in the Electric field is difficult because of the complex structure. The coal-bearing rocks occur in a synclinal area within a fault 

block that has been downdropped several thousand feet. Coal-bearing 

rocks on the northeast side of the fault block are sheared and overturned and are in contact with Precambrian crystalline rocks. The 

fault block itself has been cut by many subordinate faults, the larger 

of which separate the field into the three component parts. The coalbearing rocks dip steeply in most parts of the field and locally are overturned ; in places, however, they are nearly horizontal. Because of the 

faults and steep dips only a small part of the coal can be considered 

minable by present standards.

The deformation of the coal-bearing rocks is responsible for the relatively high and variable rank of the coal. Most of the coal ranges in 

rank between high-volatile C and medium-volatile bituminous, but locally in fault zones it is semianthracite. An analysis, on the as-received 

basis, of a sample of coal from the Aldridge mine at Aldridge, Park 

County, is as follows (U.S. Bur. Mines, 1932, p. 54-55) :

Moisture ___ _ . .

Volatile matter- _. .

Fixed carbon _ . _

Ash ___ ___ __._.

Percent 

_ _ 4.0

_ 22. 5

59.3

___ 14. 2

Sulfur ______

Air-drying loss__ _ _

Btu __ _ __

Percent 

. _ __ 0.6

._ _ __ 2.7

- _ 12. 760
COKING-COAL DEPOSITS, WESTERN UNITED STATES G17

This sample is from one of the more highly deformed areas and 

probably contains higher fixed carbon and lower volatile matter than 

most coal in the field. (See Calvert, 1912b, p. 421.)

Of the three coal beds in the Electric field, the No. 1 has the strongest coking properties. Locally, however, coal from the two lower beds 

is also suitable for coking. Practically all coal mined in the past was 

used to manufacture coke. During the early 1900's when coke production was at a peak, 125 beehive ovens were in operation in the area. 

Most of the coke was shipped to copper smelters at Anaconda and 

Butte. The coke was of good quality, although the operators were unable to meet the requirements of those smelters for coke with an ash 

content of less than 18 percent (Calvert, 1912b, p. 419).

Combo and others (1949, p. 18) estimated that the inferred original 

resources of coal in the field in beds 3 feet or more thick and less than 

1,000 feet below the surface totaled about 20 million tons. This estimate was based on assumed continuity of three beds throughout the 

total productive area of the field and is, therefore, the maximum potentially present. The inferred original resources in the No. 1 bed are 

roughly one-third this amount, or about 7 million tons. When this 

figure is reduced to allow for past production and losses in mining and 

for estimated future losses in mining, the estimated recoverable resources in the No. 1 bed are about 3 million tons.

GREAT FALLS FIELD, CASCADE AND JUDITH BASIN COUNTIES, MONT.

The Great Falls coal field, in Cascade and Judith Basin Counties, 

Mont. (fig. 1, loc. 5), includes three adjacent basins of minable coal, 

which have given rise to the three mining districts, from west to east, 

the Sand Coulee, Otter Creek, and Sage Creek districts. The three 

districts compose an area of at least 334 square miles (Fisher, 1909). 

The coal is about 60 feet above the base of the Kootenai Formation, 

which consists of interbedded massive sandstone and shale of Early 

Cretaceous age. Local variations in the thickness of the coal are characteristic, but at least one bed, ranging from 2% to 14 feet in thickness, including partings, is present throughout the field. Near Belt in 

the Sand Coulee district, where the coal has been mined extensively, the 

bed ranges typically from 4 to 9 feet in thickness and is separated into 

two or three benches by partings of shale and impure coal, which must 

be removed. The individual shale partings range in thickness from a 

fraction of an inch to 1 foot, and usually they are easily separated from 

the coal above and below.

Throughout the Great Falls field the coal-bearing rocks dip gently 

3°-5° NE., but they may steepen locally. In some places, steeper dips 

present difficulties in mine haulage. Faults having displacements of
G18 CONTRIBUTIONS TO ECONOMIC GEOLOGY

5-20 feet and igneous rocks, principally basalt dikes, break the continuity of the coal-bearing rocks locally, but neither of these disruptions causes unusual mining problems. There is no report of coal 

having been altered or changed in rank by contact with the igneous 

rocks.

The coal in the Great Falls field is of high-volatile B and C bituminous rank. An analysis, on the as-received basis, of a sample of 

coal from the Deep Creek mine in Cascade County, 22 miles southwest 

of the town of Great Falls, is as follows (U.S. Bur. Mines, 1932, 

p. 42-43):

Volatile matter__ _

Fixed carbon. _ _

Ash _ __ _ _

Percent 

__ _ 5.9

___ 32. 8

__ 49. 3

_ 12.0

Sulfur _ _

Btu ____ __ __

Percent 

... __ - 4.0

. __ __ _ 2.4

._ _ __ _ _ 11.470

The sulfur content is due primarily to the presence of pyrite nodules, 

which range in diameter from that of a pinhead to a maximum of 

about 4 inches, the average being 1 inch. The nodules and much of 

the ash can be removed by washing.

Only certain benches of the coal have coking properties. The coke 

ovens formerly operated at Belt, Mont., by the Anaconda Mining Co. 

were abandoned, in part because of the difficulty and expense of separating coking from noncoking coal and in part because of the decline 

in importance of the blast furnace in nonferrous smelting.

In the Great Falls field the estimated original resources of coal 

classed as measured and indicated, according to the definitions on 

page G9, total 309 million tons. This coal is in several beds, each 

at least 24 inches thick, beneath no more than 500 feet of overburden. 

Some of this coal has been mined, and the amount remaining that is 

of coking quality can be ascertained only by actual tests. The remaining resources are, however, believed to be sufficient to supply a 

moderate industrial demand for coke of lower quality. Additional 

information about the resources of coal in the Great Falls field and 

other fields in Montana is contained in reports by Combo and others 

(1949, 1950).

WYOMING

The coal beds in Wyoming are of Cretaceous and Tertiary age and 

are preserved chiefly in broad synclinal basins lying between the mountain ranges. Around the edges of these basins the coal-bearing rocks 

may dip steeply as a result of later uplift of the surrounding mountains, but in the central parts of the basins the rocks are virtually 

flat-lying. Many of the coal beds have been subjected to little or no 

deformation. Consequently, Wyoming, which has large resources of
COKING-COAL DEPOSITS, WESTERN UNITED STATES G19

coal, contains mostly subbituminous coal and low-rank bituminous 

coal. Coal having coking properties occurs only in three small areas.

The Willow Creek (No. 5) coal bed of Late Cretaceous age in the 

Kemmerer-Willow Creek field, Lincoln County, has coking properties probably as a result of the rather close folding of the rocks. In 

the Rock Springs field, Sweetwater County, where the coal-bearing 

formations have been affected by the Rock Springs uplift, the lowermost coal bed, of Late Cretaceous age, has coking properties but yields 

a product that is poor in quality. The Cambria field, on the western 

flank of the Black Hills, contains a coal bed of Early Cretaceous age 

that was mined formerly as a coking coal.

The carbonizing properties of coal from the Kemmerer-Willow 

Creek and Rock Springs fields have been discussed by Landers and 

others (1961).

KEMMEREK-WILLOW CHEEK FIEU>, LINCOLN COUNTY, WYO.

.The coal field near Kemmerer, in southwestern Wyoming (fig. 1, 

loc. 6), which has been described by Schultz (1914), comprises several 

areas of coal-bearing rocks in a long, narrow synclinal belt that extends 

northwestward into Idaho. A part of this belt, 12 miles long and 

about 12 miles north ;of Kemmerer, has been studied by Andrews 

(1944) and by Toenges and others (1945).

Coal having coking properties in the Kemmerer-Willow Creek area 

occurs in the Willow Creek and Kemmerer coal zones in the Frontier 

Formation of Late Cretaceous age. Higher in the section, coal generally unsuitable for making coke occurs in the Adaville Formation, 

also of Late Cretaceous age. Both the Willow Creek and the Kemmerer zones contain several closely spaced coal beds. The most important of these is near the center of the Willow Creek zone and is 

known as the Middle Main bed or the Willow Creek (No. 5) bed. 

Henceforth, it will be termed the "Middle Main [Willow Creek 

(No. 5)] bed." The thickness and character of this bed have been 

proved by drilling and sampling for a distance of 41/£ miles along the 

outcrop on the east side of the synclinal belt, and with the exception of 

two small areas of thin coal, the bed ranges in thickness from 4 feet 

3 inches to 4 feet 10 inches. Two clay partings, each 1-2 inches thick, 

generally occur 7-14 inches below the top of the bed. These partings 

can be removed by washing but only with the loss of some coal. The 

bed is overlain in the proved area by a 2-foot clay zone, which in turn 

is overlain by a thin coal, generally 15-25 inches thick.

On the eastern limb of the syncline, the rocks dip 28°-33° W. The 

regularity of dip, together with an absence of faults, makes this location favorable for mining. The rocks on the western limb, on the 

other hand, dip at least 45° and locally may be vertical or overturned.
G20 CONTRIBUTIONS TO ECONOMIC GEOLOGY

Mining would be difficult on the western limb of the syncline, but the 

Middle Main [Willow Creek (No. 5)] bed in this area ranges from 

3 feet 2 inches to 6 feet 5 inches in thickness and has no partings. 

The coal in the Middle Main [Willow Creek (No. 5) ] bed is of highvolatile A bituminous rank. An analysis, on the as-received basis, 

of a sample of coal from a drill hole at the NE. cor. sec. 12, T. 23 N., 

E. 116 W., sixth principal meridian, is as follows (Toenges and others, 

1945, p. 44-45):

Percent

Moisture ___________ 2. 8 

Volatile matter_______ 36.9 

Fixed carbon_______ 51.4

Ash __

Sulfur

Percent

8.9

.6

Btu _________________ 12, 780

Coke manufactured from coal from this bed alone is unsuitable for 

use in the blast furnace. With the addition of 50-60 percent of coal 

from the Sunnyside region, Utah, however, it will provide a coke 

nearly comparable to that made from 100 percent Sunnyside coal. 

The percentage of Sunnyside coal needed in the blend can probably 

be reduced by washing the coal from the Middle Main [Willow Creek 

(No. 5) ] bed to remove impurities. The physical and chemical properties of cokes derived during tests of various blends of the Middle 

Main [Willow Creek (No. 5) ] coal and other coals are described in the 

report by Toenges and others (1945, p. 14-25).

In the area proved by drilling, which includes 1,710 acres, or nearly 

3 square miles, the estimated original resources of coking coal in the 

Middle Main [Willow Creek (No. 5)] bed are 15 million tons. Assuming minimum mining losses, the recoverable coal totals 11 million 

tons (Toenges and others, 1945, p. 10-11). Making generous additional allowances for losses incurred in eliminating the impurities contained in the two clay partings, the recoverable clean marketable coal 

in the area proved by drilling totals at least 8 million tons (Andrews, 

1944).

South of the area of drilling, the coal in the Middle Main [Willow 

Creek (No. 5)] bed presumably has the same coking properties as the 

coal just described. In the five townships where the Middle Main 

[Willow Creek (No. 5)] bed is 28-42 inches thick, the original measured resources of coal under less than 2,000 feet of overburden total 

38 million tons, and the original indicated resources total 59 million 

tons. Additional measured resources of 9 million tons of coal and 

indicated resources of 39 million tons of coal lie at depths between 

2,000 and 3,000 feet.

Additional information about the coal resources of the KemmererWillow Creek field and other fields in Wyoming is contained in reports 

by H. L. Berryhill, Jr., and others (1950,1951).
COKING-COAL DEPOSITS, WESTERN UNITED STATES G21 

ROCK SPRINGS FIELD> SWEETWATER COUNTY, WYO.

The coal in the Rock Springs field (fig. 1, loc. 7) occurs in the Rock 

Springs and Almond Formations of the Mesaverde Group (Upper 

Cretaceous), in the Lance Formation (Upper Cretaceous), the Fort 

Union (Paleocene) Formation, and in the Wasatch Formation 

(Eocene). As described by Schultz (1909, 1910), the thickest and 

best coal in the field is in the Rock Springs Formation, which is 600- 

1,400 feet thick. This formation contains at least 12 coal beds individually 2-10 feet thick and many other beds less than 2 feet thick. Partings of shale, impure coal, and sandstone, ranging in thickness from a 

fraction of an inch to as much as 1 foot, occur in most of the beds.

The coal crops out on the flanks of the Rock Springs uplift, a low 

dome about 90 miles long and 40 miles wide. The beds on the west 

flank of the uplift dip 15°-30° W.; those on the east flank dip 5°-10° E. 

Normal faults break the continuity of the beds on the flanks of the 

uplift, and in areas where these faults are concentrated they may increase the difficulty and expense of mining. Intrusions and extrusions of igneous rock crop out in the northern half of the uplift, but 

no alteration of the coal by igneous activity has been observed.

The coal in the Rock Springs Formation is of high-volatile C bituminous rank. An analysis, on the as-received basis, of a sample of coal 

from the Rock Springs No. 7 bed from the Superior A mine, threequarters of a mile southeast of Superior, Sweet\vater County, is as 

follows (U.S. Bur. Mines, 1931a, p. 74-75):

Volatile matter.. _ .

Fixed carbon _.

Ash__ ____ _._ .

Percent

. _____ 12. 7

. __ 32.8

._ _ 50. 0

. __ 4.5

Sulfur

Air-drviDfir ° loss

Btu _ ___ _.

Percent

. _ __ 0.8

. ______ 5.6

. _ ___ 11.720

Coal from some of the beds in the Rock Springs Formation, particularly the No. 7 bed, will yield a poor grade of coke that is unsuitable 

for metallurgical purposes but that has potential use by industries with 

less stringent specifications. In 1963, the Gunn-Quealy Coal Co. began 

construction near Rock Springs of a plant designed to manufacture 

coke from local coal. The coke is intended for use by industries in 

Idaho producing elemental phosphorus by the electric furnace method 

(U.'S. Bur. Mines, 1964b, p. 1212).

According to H. L. Berryhill, Jr., and others (1950, p. 29), the estimated original resources of the No. 7 bed, where it is 28 inches or more 

thick and loss than 2,000 feet below the surface, total 899 million tons, 

of which 335 million tons is classified as measured, 393 million tons as 

indicated, and 172 million tons as inferred. At depths between 2,000 

and 3,000 feet below the surface the No. 7 bed contains additional indicated resources of 38 million tons and inferred resources of 206 million

799-641 66 4
G22 CONTRIBUTIONS TO ECONOMIC GEOLOGY

tons. Approximately 108 million tons of coal from the No. 7 bed was 

mined or lost in mining to January 1, 1950. All mining has been in 

parts of the bed included in the measured original coal resources.

CAMBRIA FIELD, WESTON COUNTY, WYO.

The coal in the Cambria field (fig. 1, loc. 8) is in a single bed that 

occurs sporadically in the lower part of the Lakota Sandstone of Early 

Cretaceous age (Darton, 1904, 1905; Stone, 1912). Abrupt changes 

in composition and thickness of the bed are common, but generally the 

bed ranges between 3 and 10 feet in thickness. Near the town of 

Cambria, where most of the past mining has been carried on, the coal 

is typically 7 feet thick and of good quality. The structure of the 

Cambria field is monoclinal and the coal-bearing rocks dip gently to 

the southwest. Coal mining began at Cambria in 1889 and ceased in 

1928. The total production during this period was a little more than 

12 million tons (Connolly and O'Harra, 1929, p. 382).

The coal in the Cambria field is of high-volatile C bituminous rank. 

An analysis, on the as-received basis, of a composite sample of coal 

taken from three locations within the Antelope No. 4 mine at Cambria 

is as follows (U.S. Bur. Mines, 1931a, p. 76-77) :

Moisture _ . _ ____

Volatile matter ____

Fixed carbon _ __

Ash _ _

Percent 

_ _ 10.8

39. 1

___ 35. 1

_ _ 15. 0

Sulfur __ _ __ _

Btu_ _ _ ________

Percent 

4.9

_ _ 8. 1

10, 340

Certain parts of this bed, presumably of greater purity than the 

remainder, have good coking qualities, and in the past these parts were 

employed for manufacturing coke to supply smelters and refineries 

in the Black Hills.

The coal used for making coke was chiefly the slack produced in 

mining operations, and no effort was made to clean or wash it before 

coking (Connolly and O'Harra, 1929, p. 384). Coke was produced 

principally during the years 1891-1900; during this 10-year period, 

107,000 short tons of coke was made from 225,000 short tons of coal.

According to H. L. Berryhill, Jr., and others (1950, p. 34, 36, 38), 

the Cambria field contained estimated original resources of 22 million 

tons of coal at least 28 niches thick and covered by no more than 1,000 

feet of overburden. The coal that was measured or indicated by 

geologic evidence constituted 19 million tons of the total resources, and 

an additional 3 million tons was inferred to be present from general 

geologic knowledge of the area. Accumulated past production totals 

12 million tons, and these resources have consequently been almost 

entirely mined or lost in mining. Certainly the readily accessible
COKING-COAL DEPOSITS, WESTERN UNITED STATES G23

resources of coking coal, which represented only a small percentage of 

the total, are now depleted.

UTAH

The Sunny side-Castlegate field, Carbon County, is the only area in 

Utah containing coal with the qualities necessary for the production 

of satisfactory metallurgical coke. Two other areas, the Mount 

Pleasant field, Sanpete County, and the Kolob field, Iron County, contain coal that will form weaker and less desirable cokes.

SUNNYSIDE-OASTLEGATE FIELD, CARBON COUNTY, UTAH

The Sunnyside-Castlegate field (fig. 1, loc. 9), which is a strip about 

40 miles long at the western end of the large Book Cliffs field of 

Colorado and Utah, is the most important source of coking coal in 

the West. In 1963, coal production in Carbon County, Utah, which 

embraces the 'Sunnyside-Castlegate field, totaled nearly 3% million 

tons, or about 80 percent of the total production in Utah (U.S. Bur. 

Mines, 1964a, p. 140). Of this 3% million tons, about 2 million tons 

was used for the production of coke. Half of this, or about 1 million 

tons, was shipped to southern California for use in the Fontana plant 

of the Kaiser Steel Corp., and half was used in Utah (U.S. Bur. Mines, 

1964b, table 1, p. 1-19). The coal has been mined extensively for coking at Sunnyside, Columbia, and Horse Canyon.

As described by Clark (1928), the coal in the Sunnyside-Castlegate 

field is in a zone about 500 feet thick near the base of the Mesaverde 

Group of Late Cretaceous age. This sequence consists of massive beds 

of sandstone, which crop out conspicuously in the Book Cliffs, and 

alternating beds of shale and coal. As many as nine coal beds occur 

locally in the coal-bearing zone, and a minimum of two occur at any 

one locality. The coal beds are generally lenticular.

The Lower Sunnyside bed, which is mined extensively near Sunnyside for use in the manufacture of coke, crops out for a distance of 

about 25 miles. It ranges in thickness from 5 to 11 feet in the area of 

active mining but thins both to the northwest and to the south. 

Although partings are uncommon in this field, the bed is separated 

locally into two benches by a parting of sandy shale 1-2 feet thick.

The Sunnyside-Castlegate coal field is on the north and northeast 

flanks of the San Rafael Swell. At the town of Sunnyside, where 

mining has been most extensive, the coal beds dip about 12° NE., under 

the Book Cliffs. Northwest and southeast of Sunnyside, however, the 

dip of the rocks decreases to 2°-4°. Except for a few minor faults 

concentrated mostly at the south end of the field, there are no structural complications. Mining in the field is, however, handicapped 

by infrequent coal-mine bumps in which pillars of coal collapse with
G24 CONTRIBUTIONS TO ECONOMIC GEOLOGY

explosive violence as a result of accumulated stress in the roof rock. 

Recent studies by Osterwald (1961, 1962) have done much to show 

the cause of, and methods of preventing, bumps.

The coal in the Sunnyside-Castlegate field is of high-volatile A and 

B bituminous ranks. An analysis on the as-received basis of a sample 

of coal from the Lower Sunnysicle bed at Sunnyside is as follows 

(Reynolds and others, 1946, p. 12-13) :

Percent

Moisture _ _. _ 4. 5 

Volatile matter..______ 38. 5 

Fixed carbon_.__ 51. 2 

Ash_______________ 5. 8

Sulfur___. 

Air-drying loss.

Percent 

1.3 

2.2

Btu (moist, mineral-matter

free) _______________ 14, 020

The Lower Sunnyside coal is a conspicuous example of a highvolatile bituminous coal used successfully in byproduct ovens for the 

production of satisfactory metallurgical coke. A typical analysis of 

coke produced from Lower Sunnyside coal from the Columbia mine 

shows the following physical and chemical properties (Reynolds, 

1946, p. 44-48):

Apparent specific gravity___ 0.78

True specific gravity______ 1. 89

Btu________________ 12, 790

Volatile matter_,__percent_ 1.7

Fixed carbon___________do 87.4

Ajsh___________percent 10. 9 

Sulfur___________do__ . 9 

Cell space_ ______do 58.7 

Tumbler and shatter tests: satisfactory 

for all purposes.

Coke produced from Sunnyside coal yields only about two-thirds 

of its weight in furnace-size pieces, which contain many lateral and 

transverse fractures, but otherwise the coke is hard and holds up 

well in the blast furnace.

At the town of Sunnyside, more than 800 beehive ovens have been 

constructed over the years. Many of these were in use on an emergency basis during World War II. Nearby at Columbia there are 

additional beehive ovens. Today most of the coal is processed in 

modern byproduct coke plants. Coke made from Sunnyside coal is 

used in the Columbia Steel plant at Iroriton, Utah, the Geneva Steel 

plant near Provo, Utah, the Fontana plant of the Kaiser Steel Corp. 

in southern California, and in local sugar refineries.

The coking qualities of the coal decrease northwestward from the 

Sunnyside area to Castlegate where the coal is no longer used for 

coking purposes, though prior to 1903 it was the main source of supply 

for the State. Similarly, the coal in the Huntington Canyon area 

south of Castlegate has coking properties, but coke made from this 

coal is inferior to that produced at Sunnyside.

The total resources of coking coal in the Lower Sunnyside bed are 

large enough to supply anticipated demands. Detailed calculations
COKING-COAL DEPOSITS, WESTERN UNITED STATES G25

of the resources in the Sunnyside-Castlegate field as measured along 

the outcrops and indicated by the continuity of the beds have been 

tabulated by township and by individual bed by Clark (1928, p. 101- 

102,161). These figures show that the Lower Sunnyside bed contains 

estimated original resources ranging from 5 to 9 million tons per 

square mile in a belt about 10 miles long and averaging about 2 miles 

in width northwest of the town of Sunnyside. This coal lies under 

less than 2,000 feet of overburden. Because commercial mining in 

the Lower Sunnyside bed is restricted for the most part to an area 

southeast of this belt, the entire tonnage, less normal expectable losses 

in mining, is available for future needs. Additional resources are in 

the Lower Sunnyside bed in the area of active mining, which extends 

from about 1 mile northwest of Sunnyside southeastward to several 

miles south of Horse Canyon.

MOUNT PLEASANT FIELD, SANPETE COUNTY, UTAH

The Mount Pleasant coal field (fig. 1, loc. 10), on the west side of 

the Wasatch Plateau, is favorably located with respect to the western 

steel industry and has been carefully investigated as a source of coking 

coal. The area was mapped by the U.S. Geological Survey in 1942 

(Duncan, 1944), and an exploratory hole was drilled by the U.S. 

Bureau of Mines to obtain samples for analysis (Toenges and Turnbull, 1943).

The six coal beds penetrated in the drilling are in the lower 200 

feet of the Blackhawk Formation of Late Cretaceous age and range 

in thickness from 18 inches to 5 feet 8 inches. On the western margin 

of the Wasatch Plateau, the rocks are broken by many faults, and 

west of the fault zone the coal beds have been downdropped. In this 

area the coal beds lie more than 2,000 feet below the present surface, 

beyond the present practical depth of mining. On the east side of the 

fault zone, however, the coal beds were found in the test hole at depths 

of only 955 to 1,151 feet below the surface.

An analysis, on the as-received basis, of a core sample of coal from 

one of the thicker beds in the Mount Pleasant field is as follows 

(Toenges and Turnbull, 1943, p. 14, sample D):

Percent

Sulfur ________________ 0.6 

Air-drying loss ________ 1. 4

Percent

Moisture___________ 3.2 

Volatile matter._______ 42. 9 

Fixed carbon__.______ 45. 3 

Ash______________ 8. 6 Btu _________________ 12,890

Coking tests made on samples from the five thicker beds, all of 

which are of high-volatile A and B bituminous ranks, as is the coal 

from the Lower Sunnyside bed, showed that the resulting coke was 

softer, considerably weaker, and more fingery than coke manufactured
G26 CONTRIBUTIONS TO ECONOMIC GEOLOGY

from Sunnyside coal. It was concluded, therefore, that coal from the 

Mount Pleasant area is not suitable for the production of blast-furnace 

coke to be used in smelting iron ore.

KOLOB FIRLI>, IRON, WASHINGTON, ANI> KANB COUNTIES^ UTAH

The western part of the Kolob field (fig. 1, loc. 11) has been described by Averitt (1962) and the eastern part by Cashion (1961). 

The coal beds in this field crop out in cliffs bordering the Kolob Terrace or in canyons eroded in the margins of the terrace. The coal 

beds occur in the Tropic Shale and in the overlying Straight Cliffs 

Sandstone, both of Late Cretaceous age. In the western part of the 

field near Cedar City, Utah, the single important coal bed occurs in 

a 10- to 14-foot carbonaceous sequence, termed the "Upper Culver 

coal zone," at the top of the Tropic Shale. This bed, including impure 

layers at the top and several partings, is 6-8 feet thick. It is mined 

extensively, primarily to supply fuel for the production of electric 

power.

The coal in the western part of the field has heat values ranging 

in general from 10,350 to 11,430 Btu on the as-received basis, ash contents ranging from 4.7 to 12.2 percent, sulfur contents from 5.6 to 6.7 

percent, and moisture contents from 6.1 to 13.5 percent. An analysis, 

on the as-received basis, of a composite sample of coal from the 

Webster-Nelson mine in Right Hand Canyon, a few miles east of 

Cedar City, is as follows (Averitt, 1962, p. 55) :

Percent

Moisture____.______ 6.0 

Volatile matter_______ 41.1 

Fixed carbon_._____ 40.9 

Ash _____________ 12.0

This coal is near the borderline between subbituminous A and highvolatile bituminous C ranks and is lower in rank than most coals used 

in the manufacture of coke. The coke produced from this coal is high 

in sulfur and tends to be too friable for metallurgical use. In the 

early iron-making experiments of Utah pioneers, this coke proved to 

be unsatisfactory and was replaced by charcoal.

Most of the accessible coal in the western part of the Kolob field 

is in the Cedar Mountain quadrangle. In this quadrangle, measured 

and indicated resources remaining as of January 1, 1956, in the important coal in the Upper Culver coal zone totaled about 200 million 

tons, of which about half is recoverable. These resources are in a bed 

6 feet thick and generally less than 1,000 feet below the surface (Averitt, 1962, p. 61-62). Additional resources are present north and east 

of the Cedar Mountain quadrangle, and much larger resources of

Sulfur ______________

Air-drying loss _____

Btu ____ _ _ _ -

Percent 

____ 6.5

_ __ 2. 6

_ __ 11.260
COKING-COAL DEPOSITS, WESTERN UNITED STATES G27

comparable coal are present in the eastern part of the Kolob field, 

which has been described by Cashion (1961).

COLORADO

Four areas in Colorado yield coal used at present or in the past 

for the manufacture of metallurgical coke. Two of these areas, the 

Somerset-Crested Butte-Carbondale region and the Eaton Mesa region 

of Colorado and New Mexico, are important centers of western coking 

coal production. The Durango and San Juan Eiver fields in southwestern Colorado contain coal used in the past for the manufacture of 

coke to supply local nonferrous smelters. Information about coal in 

these and other fields in Colorado has been summarized by Landis 

(1959).

SOMERSET-CRESTED BUTTE-CARBONDALE REGION, DELTA, GUNNISON, AND PITKIN COUNTIES, COLO.

The Somerset-Crested Butte-Carbondale region (fig. 1, loc. 12) 

is a major source of coking coal in the west, comparable in area and 

resources to the Eaton Mesa region in Colorado and New Mexico and 

to the Sunnyside field, Utah. The general geology of the region has 

been described by Emmons and others (1894) and by Lee (1912), 

and the detailed geology of specific parts of the region is described in 

more recent reports cited below.

The Somerset-Crested Butte-Carbondale "region is on the southeastern rim of the Uinta Basin, a large structural basin that extends 

into Utah. Igneous intrusions and deformation associated with the 

uplift of the Eocky Mountains have, however, so disturbed the rocks 

in the region that the relations of the structure to the Uinta Basin 

are not clearly defined.

The coal beds are in the Bowie Shale Member and the overlying 

Paonia Shale Member of the Mesaverde Formation of Late Cretaceous 

age. Several coal beds of minable thickness occur in each of the two 

members, and a total of eight beds have been observed at one locality. 

Correlation of the coal beds and accurate measurements of their thickness are difficult because of deformation, but, in general, the thicker 

beds are 4-12 feet thick.

As a result of the deformation and the intrusions, the coal ranges 

in rank from bituminous to anthracite. In general, the coal in the 

Bowie Shale Member is slightly higher in rank than the coal in the 

Paonia Shale Member, but this difference is nonexistent where the 

coals have been altered. The variation in rank in the region is so 

great that no single analysis or group of analyses is adequate to show 

the character of the coal, but for the most part, the ash content is 

moderate and the sulfur content low.
G28 CONTRIBUTIONS TO ECONOMIC GEOLOGY \

Coal having coking properties occurs at many places in the region, ^ 

but because of the range in rank and quality of the coal, the coke produced shows a comparable range in quality.

Because of its diversity, the region is best discussed in three parts: 

the Coal Creek district of the Somerset field, the Crested Butte field 

proper, and the Carbondale field.

! 

SOMERSET FIELD, COAL CREEK DISTRICT 4

The Coal Creek district is in T. 13 S., R. 89 W., Gunnison County, 

in the easternmost part of the Somerset or Paonia field. In the Coal \ 

Creek district the Mesaverde Formation is divided from bottom to top 

into the Eollins Sandstone Member, the lower coal member (in general 

equivalent to the Bowie Shale Member), the upper coal member (in 

general equivalent to the Paonia Shale Member), and the barren 

member. Exploration in the Coal Creek district by V. H. Johnson 

(1948) and by Toenges and others (1952) has shown that the lower 

coal member contains two principal beds. The lower bed, known as 

the Snowshoe, is 9-15 feet thick in the central part of the district, 

but it thins and splits into two benches to the north and west, each 

bench ranging in thickness from 1 to 7 feet. The upper or Bear bed, 

although locally minable, is less than 3 feet thick throughout most of 

the Coal Creek district. The coal in the upper coal member of the 

Mesaverde is of no economic importance.

To test the coking properties of coal from the Coal Creek district, 

a selected area of about 6 square miles near the center of T. 13 S., E. i, 

89 W., was core drilled by the U.S. Bureau of Mines (Toenges and ' 

others, 1952). Analyses and carbonization tests showed that coal ^ 

from the lower bench of the Snowshoe bed, termed the "lower bed," 

and from the Bear bed, termed the "upper bed," yields a stronger 

coke than does coal from the Sunnyside bed in Utah. The coal from 4 

the upper bench of the Snowshoe bed, termed the "middle bed," 

yields a coke slightly inferior to coke made from Sunnyside coal. All 

three cokes are satisfactory in chemical composition, having sulfur x 

contents of 0.4MX9 percent and ash contents of 6.3-10.9 percent.

In the area proved by drilling, the measured original reserves of 

coal total 121 million tons, of which 108 million tons will yield coke of ;. 

metallurgical quality (Toenges and others, 1952, p. 13). Assuming » 

a 50 percent recovery in mining, recoverable reserves of metallurgical j 

coking coal are about 54 million tons. All this coal lies under moderate *r 

to heavy overburden. At the confluence of Anthracite and Coal 

Creeks, for example, the upper bed was penetrated in a drill hole at a 

depth of 658 feet and the lower bed at 695 feet. East and northeast 

of this point the thickness of the overburden increases rapidly, and 

most of the coking coal lies 1,000-2,000 feet beneath the surface.
COKING-COAL DEPOSITS, WESTERN UNITED STATES G29

Extrapolation of the data reported by Toenges and others (1952, 

p. 13) suggests that coal in the east half of T. 13 S., E. 89 W., is more 

strongly coking than coal in the west half and should be suitable for 

the manufacture of metallurgical coke. About 7 miles to the southwest in the Minnesota Creek area the coal is also less strongly coking 

than coal in the east half of T. 13 S., E. 89 W. (Toenges and others, 

1949, p.20-29).

These few facts suggest that coal suitable for the manufacture of 

metallurgical coke lies, in general, in the east half of T. 13 S., E. 89 

W. Such coal probably also occurs in townships to the east, northeast, and southeast toward a cluster of small masses of igneous rock 

associated with the Crested Butte intrusives. In these townships the 

coal is largely below drainage, and the amounts available, although 

presumably large, can be ascertained only by exploratory drilling.

CRESTED BUTTE FIELD

The Crested Butte field is in central Gunnison County in an area 

of much greater structural complexity than that of the Coal Creek 

district described above. In the Crested Butte field the coal-bearing 

rocks have been folded, faulted, and intruded by igneous rocks, and as 

a result the coal ranges locally in rank from subbituminous A to anthracite. The field has been mapped by Emmons and others (1894) 

and by Lee (1912), and the metamorphism of the coal has been studied 

by Dapples (1939).

The coal in this field is in the lower part of the Paonia Shale Member 

of the Mesaverde Formation. As many as five beds crop out near the 

former mining towns of Crested Butte and Anthracite, but only one 

bed is present at Floresta, about 10 miles west of Crested Butte.

Landis (1959, p. 147) estimated original coal resources totaling 244 

million tons in an area of 35 square miles near the outcrops of coalbearing rocks in this field. Of this tonnage, about 15 percent is anthracite and semianthracite, and the remainder is bituminous coal 

that has coking properties. Additional resources should be present 

in unexplored areas downdip from the outcrops.

CARBONDALE FIELD

The Carbondale field extends northward from the Crested Butte 

field through northern Gunnison, Pitkin, and Garfield Counties. In 

this field, the coal is in four zones in the Mesaverde Formation, of 

which two or more are present at most localities. Most of the coal 

in the Carbondale field dips 10°-45° W. under the Piceance Creek 

lobe of the Uinta Basin, except near intrusives of Elk Mountain where 

the beds are locally overturned.
G30 CONTRIBUTIONS TO ECONOMIC GEOLOGY

The coal ranges in rank from anthracite near Crested Butte to 

high-volatile B bituminous in Garfield County. Coal with the strongest coking properties is centered in Pitkin County. In this part of 

the field there are 10 coal beds that individually exceed 42 inches in 

thickness. As estimated by Donnell (1962), these beds contain about 

150 million tons of coal that has less than 1,000 feet of overburden 

and an additional 150 million tons that has 1,000-2,000 feet of overburden. Larger amounts of coal are in thinner beds and at greater 

depths.

In the early part of the 20th century, the Carbondale field was an 

importance source of coking coal, and mining was carried on actively 

around the towns of Placita, Gulch, and Coal Basin. The cumulative 

production from these areas prior to 1919 totaled several million 

tons. After World War I, production declined markedly because 

of the postwar decline in industrial activity, the decrease in use 

of coke for nonferrous smelting, and the competition from coal in 

the Eaton Mesa region and the Sunnyside-Castlegate field. Between 

1919 and 1953, production from the field was less than 50,000 tons 

annually. In 1953, however, mines were opened in the Thompson 

Creek area to supply coking coal to the Geneva, Utah, plant of the 

United States Steel Corp., and in 1956 the Dutch Creek mine was 

opened in the Coal Basin area. In 1964 the output of these mines was 

more than 600,000 tons. The coal is moved by truck to the railhead 

at Carbondale, then by train to Provo, Utah.

SAN JUAN RIVER FIELD, MONTROSE, SAN MIGUEL, DOLORES, AND 

MONTEZUMA COUNTIES, COLO.

In the San Juan River field (fig. 1, loc. 13) several thin discontinuous beds of coal occur in the Cretaceous Dakota Sandstone, which is 

virtually flat lying. These coal beds locally are as much as 5 feet 

thick, and at many places they are more than 3 feet thick. They 

have been mined only on a very small scale for local use. In the past, 

low-grade coke was made from coal mined near Norwood, in Montrose 

and San Miguel Counties, and near Rico, in Dolores County. The coal 

mined at Rico was 20 inches thick, and the coke produced was used 

at a nearby smelter (Hills, 1893, p. 359) until a railroad connection at 

Durango gave access to the superior coal in the Durango field. In 

general, the San Juan River field is no longer considered as a source of 

coal for the production of industrial coke.

DURANGO FIELD, LA PLATA COUNTY, COLO.

The Durango field (fig. 1, loc. 14), which lies on the northern side 

of the San Juan coal basin of Colorado and New Mexico, has been 

described by Taff (1907) and Zapp (1949). Coal in this field occurs 

in the Fruitland Formation and in the older Menef ee Formation, both
COKING-COAL DEPOSITS, WESTERN UNITED STATES G31

of the Mesaverde Group of Late Cretaceous age. The Fruitland contains subbituminous coal that is not suitable for coking. The Menef ee, which consists of interbedded sandstone and shale, contains near 

the middle three and in some places four minable beds of coal that 

have coking properties. At least two of these beds have been mined 

extensively near Durango.

The minable coal beds in the Menef ee Formation range in thickness 

from 2 to 7 feet, but partings of shale and impure coal, each several 

inches thick, generally divide the beds into benches containing 1-6 

feet of coal.

All the coal-bearing rocks dip to the south or southeast at angles 

ranging from 6° near Hesperus, 8 miles west of Durango, to 40° in 

the area 6 miles northeast of Durango. A few faults of small displacement are present in the field, but they do not interfere with 

mining operations.

Most of the coal in the Menefee Formation is of high-volatile A 

bituminous rank. An analysis, on the as-received basis, of a sample 

of coal from the Hesperus mine is as follows (U.S. Bur. Mines, 1937, 

p. 88-89):

Moisture _____ _

Volatile matter- _____

Fixed carbon _ _____

Ash _______ _____

Percent 

__ _ 5.6

__ 36. 2

__ 52. 5

5.7

Sulfur ______ __

Air-drying loss _ _____

Btu __ __ ___ _

Percent 

. _______ 0.5

________ 2.3

_ ____ 13.120

Beehive ovens formerly in operation at Durango and Porter pro- 

;< duced coke used for smelting purposes. Tests by the Bureau of Mines 

of the agglutinating, swelling, and plastic properties of 19 samples of 

coal from this area indicated that most of the samples had good coking 

qualities and that many were suitable for use in byproduct ovens 

(Fieldner and others, 1945, p. 58). Although there are local variations in the coking quality of the coal in the Durango area, some of 

the coal in the Menefee Formation probably could be treated by

 > modern cleaning and processing methods and used to manufacture 

metallurgical coke.

The measured original resources of thicker accessible coal in the 

Durango field, as estimated by Zapp (1949), total 67 million tons. 

This coal is in beds more than 42 inches thick at depths of less than 

1,000 feet below the surface. The remaining measured resources

"> as of January 1, 1949, total 64 million tons, of which 32 million tons 

can be classified as recoverable resources, assuming 50 percent recovery of the coal. Only a small amount of coal has been mined

-* since the 1949 estimate. Larger indicated and inferred resources 

{ of coal are in the field at depths from 1,000 to 3,000 feet below the 

surface.
G32 CONTRIBUTIONS TO ECONOMIC GEOLOGY

RATON MKSA REGION, HUERFANO AND LAS ANIMAS COUNTIES, COLO., 

AND COLFAX COUNTY, N. MEX.

The Eaton Mesa region (fig. 1, loc. 15) covers an area of about 

2,000 square miles in south-central Colorado and northeastern New 

Mexico. Coal from this region, when blended with small amounts 

of low-volatile coal, yields the highest quality coke in the West. 

This coke is used by steel mills of the Colorado Fuel and Iron Corp. 

at Pueblo, Colo., and by the steel mills of the Kaiser Steel Corp. 

at Fontana, Calif. The region is the second largest producer of 

coking coal in the West, being exceeded only by the Sunny side-Castlegate field in Utah.

The geology and coal resources of most of the Colorado part of 

the region, termed the "Trinidad field," have been described by Harbour and Dixon (1959), R. B. Johnson (1958, 1959), Johnson and 

Stephens (1954a, b), Wood, Johnson, and Dixon (1956, 1957"), and 

Wood, Johnson, Eargle, and others (1951). E. B. Johnson (1961) has 

summarized the geology and coal resources of the Colorado part, on the 

basis of these and older reports. The New Mexico part of the region, 

termed the "Eaton field," has been described by Lee (1922) and 

Wanek (1963). The carbonizing properties of coal in the Eaton 

Mesa region have been discussed by Eeynolds and others (1946, p. 

75-76).

The coal in the Eaton Mesa region is in the Vermejo Formation of 

Late Cretaceous age and in the Eaton Formation of Late Cretaceous 

and Paleocene age. The coal beds are generally lenticular and discontinuous, and only a few are persistent over wide areas. The coal in 

the northern part of the coal region is nonagglomerating and of highvolatile C bituminous rank and in the southern part is agglomerating 

and of high-volatile A and B bituminous ranks. On an as-received 

basis, the heating value of the coal ranges from about 11,000 to about 

14,000 Btu. Workable coal beds occur at all localities where the 

Vermejo and Eaton Formations are exposed, and as many as 10 beds 

of minable thickness have been found at one locality.

Coal beds are thicker, more numerous, and more extensive in the 

Vermejo Formation than in the Eaton Formation. Thick coal beds 

in the Eaton Formation are generally local in extent and are mainly 

in the lower part of the formation. The Vermejo contains 3-14 coal 

beds more than 14 inches thick. Many of these have been mined extensively along the southern, eastern, and northern margins of the 

region. The Eaton Formation locally contains many coal beds more 

than 14 inches thick, but only four are sufficiently thick and extensive 

to be of economic importance.

The principal structural feature of the Eaton Mesa coal region is
COKING-COAL DEPOSITS, WESTERN UNITED STATES G33

the Eaton basin, a broad asymmetric structural trough, the axis of 

which trends generally northward from near Ute Park, N. Mex., into 

Huerfano Park, Colo. The eastern limb of the trough dips gently 

westward over a broad area, whereas the western limb dips steeply 

eastward and is overturned in places. Smaller folds of varying orientations and structural relief are present throughout the coal region, 

but faults are rare. The coal-bearing rocks have been intruded by 

many dikes and sills and by a few laccoliths emanating from the stocks 

and plugs of the Spanish Peaks group of intrusives. The sills, in particular, have metamorphosed the coal at many localities and have 

destroyed many square miles of coal beds in the eastern part of the 

region and in the drainage of the Purgatoire Eiver west of 

Trinidad, Colo.

Only by the examination of a large number of analyses can the range 

in rank of the coal in the Eaton Mesa region be determined (U.S. 

Bur. Mines, 1936, p. 44-51; 1937, p. 76-84, 92-101). Where the coal 

is suitable for coking purposes, as at Stonewall in western Las Animas 

County, it is mined extensively to supply byproduct ovens of the 

Colorado Fuel and Iron Corp. at Pueblo, Colo. This coal is generally 

washed to remove some of the impurities and then blended with a small 

amount of low-volatile coal or char obtained by devolatilizing available 

low-rank coal. The resulting coke is superior to any other commercial 

metallurgical coke produced from western coal. Coking coal mined in, 

Colfax County, N. Mex., is shipped for processing to the Fontana, 

Calif., steel mills of the Kaiser Steel Corp.

Johnson (1961, p. 159, 169) estimated that the original measured, 

indicated, and inferred coal resources of the .Colorado part of the 

region, in beds more than 42 inches thick and less than 1,000 feet below 

the surface, totaled 1,103 million tons. This figure is based on mapping 

and exploration near outcrops of coal beds. Additional quantities of 

coal should be present in untested areas remote from outcrops. About 

90 percent of the total is of coking quality.

In the Eaton field, Colfax County, N. Mex., which constitutes the 

New Mexico part of the Eaton Mesa region, Eead and others (1950, 

p. 15-17, 21) estimated that the original measured, indicated, and 

inferred resources, in beds more than 42 inches thick and less than 

3,000 feet below the surface, totaled 1,324 million tons. Wanek (1963) 

has provided a more detailed analysis of coal resources in the southern 

half of the Eaton field. Most of the coal in the Eaton field is of coking

quality.

NEW MEXICO

The most important source of coking coal in New Mexico is the 

Eaton field, the southern part of the Eaton Mesa coal region, which
G34 CONTRIBUTIONS TO ECONOMIC GEOLOGY

has already been described with the Trinidad field of Colorado. The 

Monero field, southeast of Durango, Colo., in Rio Arriba County, 

N. Mex., is on the northeastern side of the San Juan Basin, and some 

of the coal beds, as at Durango, have coking properties. In the 

Cerrillos field, Santa Fe County, where the coal-bearing rocks have 

been intruded and upturned by igneous rocks, some coal has coking 

properties, but the resources of such coal are small. Similarly, only a 

small amount of coking coal remains.in the Carthage field where the 

geologic structure is very complex. In this field the coking properties 

of the coal are due to alteration accompanying the close folding and 

faulting of the sedimentary rocks.

MONERO PIBIJO, RIO ARRIBA COUNTY, N. MEX.

The Moriero coal field (fig. 1, loc. 16) has been described briefly by 

Gardner (1909), and the stratigraphy and structure of the area have 

been mapped in greater detail by Dane (1948). The coal field lies on 

the northeast side of the San Juan Basin, just south of the New 

Mexico-Colorado line. The coal having coking properties is in the 

Gibson Coal Member of the Crevasse Canyon Formation of the Mesaverde Group of Late Cretaceous age. Three minable beds, which 

range individually in thickness from 3 feet 7 inches to 4 feet, are present. Partings of sandstone and shale from 7 to 9 inches thick split the 

beds into benches of coal that are 1 foot 4 inches to 3 feet 4 inches thick.

In the vicinity of Monero and Lumberton, where most of past mining in this area was carried on, the rocks are broken by several normal 

faults, and about 2 miles west of Monero they are arched into a low 

dome. As a result, the beds dip at moderate angles to the southwest 

and northwest and locally to the southeast.

The coal in this area is commonly of high-volatile A bituminous 

rank. An analysis, on the as-received basis, of a sample of coal from 

the Kutz mine, 1 mile south of Lumberton, Rio Arriba County, is as 

follows (U.S. Bur. Mines, 1936, p. 56-57):

Percent

Moisture-___. _ 2. 4 

Volatile matter_______ 38.0 

Fixed carbon __ 52.3 

Ash____________ 7.3

Percent

Sulfur__________.____ 1. 5 

Air-drying loss _ 1.2

Btu__________________ 13, 600

According to Read and others (1950, p. 15-17), the original resources of bituminous coal in Rio Arriba County in beds 28 inches or 

more thick and less than 1,000 feet below the surface total about 17 

million tons. Larger quantities are in thinner beds and at greater 

depth. All the coal mined in the Monero field was used for railroads 

and domestic purposes. Certain coal beds, however, are known to
COKING-COAL DEPOSITS, WESTERN UNITED STATES G35

have coking qualities in parts of the field, although the resources of 

such coal have not been determined.

CEBBILLOS FIELD, SANTA FE COUNTY, N. MEX.

The Cerrillos field (fig. 1, loc. 17), one of the oldest coal-producing 

areas in the West, lies 25 miles south of Santa Fe, near the town of 

Los Cerrillos on the main line of the Atchison, Topeka, and Santa Fe 

Railway. As described by Lee (1913, p. 285-312), the coal in the Cerrillos field is in the Mesaverde Group of Late Cretaceous age, which 

consists of a massive basal sandstone overlain by a sequence of interbedded coal-bearing sandstone and shale. Three zones of coal beds, 

known in ascending order as the Miller Gulch, Cook and White, and 

White Ash coal zones, are present. The upper two zones have been 

extensively mined. The main bed of the White Ash coal zone ranges 

from 33 to 66 inches in thickness, and the main bed of the Cook and 

White zone averages 52 inches in thickness. There has been little 

development of the Miller Gulch zone, but the main bed is known to 

be approximately 40 inches thick.

The coal-bearing rocks occupy the center of a small structural basin 

and dip gently toward the center on the east and west sides, but on 

the north and south they have been steeply upturned by large igneous 

intrusions. Igneous rocks in dikes and sills have intruded the sedimentary rocks in the basin and locally have altered the coal so that it 

ranges in rank from bituminous to anthracite. Certain beds in the 

Cook and White and Miller Gulch coal zones contain coal that can be 

coked and used satisfactorily in blast furnaces, but most of the minable 

coal has been too highly metamorphosed to have coking qualities. The 

U.S. Geological Survey and the U.S. Bureau of Mines have examined 

areas where, on the basis of the distribution of the igneous rocks in 

relation to the coal beds, coking coal might be expected to occur. The 

results of this study showed that the resources of coking coal were too 

small to warrant further iexploration (Toenges, Turnbull, and Mould, 

1943; Turnbull and others, 1951).

CARTHAGE FIELD, SOCOBBO COUNTY, N. MEX.

The Carthage field, Socorro County, N. Mex. (fig. 1, loc. 18), is about 

12 miles southeast of San Antonio. As described by Gardner (1910), 

the minable coal in the field is in the Carthage bed which lies just above 

the basal sandstone of the Mesaverde Group of Late Cretaceous age 

and which averages about 5 feet in thickness. Partings of clay, shale, 

and impure coal ranging in thickness from 2 to 15 inches split the 

coal so that the principal bench is 2-4 feet thick. A second unnamed 

coal bed 30-40 feet above the Carthage bed is locally as much as 7 feet 

thick but is very impure.
G36 CONTRIBUTIONS TO ECONOMIC GEOLOGY

The Carthage field is on an uplifted fault block, which has been 

broken by a system of north-trending normal faults. Because of the 

faulting and many changes in dip, mining operations are hampered.

The coal in the Carthage field is of high-volatile A bituminous rank. 

An analysis, on the as-received, basis, of a sample of coal from the 

Government mine at Carthage is as follows (U.S. Bur. Mines, 1936, 

p. 62-63):

TVTni dfiTpp

Ash __________

Percent 

_____ 3. 7

_ _ 39.7

___ 46. 7

___ 9.9

Sulfur ______ _____

Btu _ _ ____________

Percent 

_______ 1. 0

2 2

____ 12,860

The field was opened in 1861 and was mined almost continuously 

for a long period. Prior to 1894 a few beehive coke ovens were operated at San Antonio, 12 miles west of the field. Tests of the carbonizing properties of the coal by Eeynolds and others (1946) showed 

that the coal yielded a fair coke but inferior in quality to that produced 

at Sunnyside, Utah. Most of the coal in the Carthage field has been 

mined out, or is unrecoverable, and the known areal extent of the coal 

bed at minable depth is no more than 2 square miles.

OKLAHOMA AND ARKANSAS

The coal fields in eastern Oklahoma and west-central Arkansas form 

a continuous area of coal-bearing rocks of Pennsylvanian age that 

have been folded into generally eastward-trending anticlines and synclines. Eastward-trending thrust faults are present along the crests 

of some of the larger anticlines in the southern part of the coal field. 

Normal faults are common in the northern part of the coal field. As 

a result of regional differences in the amount of folding and faulting, 

the coal increases markedly in rank from west to east. In the southwestern part of the Oklahoma field where the rocks are only moderately folded, the coal is of high-volatile bituminous rank. In eastern 

Oklahoma and in west-central Arkansas, where the deformation was 

greater, the coal is of low-volatile bituminous rank. At the east end 

of the Arkansas field, where deformation was even greater, the coal 

is semianthracite. Some of the coal from the Oklahoma-Arkansas 

field can be used directly for coke making, and the remainder, particularly the low-volatile bituminous coal, is useful for blending with 

lower rank coal.

The geology and occurrence of coal in Oklahoma and Arkansas have 

been summarized by Trumbull (1957) and Haley (1960), respectively.

HENRYETTA DISTRICT, OKMULGEE COUNTY, OKLA.

The Henryetta district in Okmulgee County (fig 1, loc. 19), only 10 

square miles in size, is one of the most extensively mined areas in the
COKING-COAL DEPOSITS, WESTERN UNITED STATES G37

Oklahoma coal field. According to Dunham and Trumbull (1955), 

most of past production has been from the Henryetta bed, in the 

Senora Formation of Pennsylvanian age. This bed ranges in thickness from 25 to 41i/£ inches, but it is about 36 inches thick over a large 

area. Throughout most of the mined area a parting of impure or bony 

coal 2-4 inches thick occurs in the middle of the bed. A second coal 

the Morris coal which lies 125 feet below the Henryetta bed, has been 

mined locally on a small scale. The coal-bearing rocks in the Henryetta district dip gently to the west. The structure and the roof rock 

are favorable for mining, and the thinness of the coal bed is only a 

minor disadvantage.

Generally the coal in the Henryetta bed is of high-volatile B 

bituminous rank. An analysis, on the as-received basis, of a sample 

of coal from this bed from the Whitehead No. 2 mine at Henryetta is 

as follows (U.S. Bur. Mines, 1928a, p. 21):

Volatile matter . .

Fixed carbon __ .___.

Ash ________ __.

Percent 

_____ 7. 6

._ _ _ 34.7

___ 52. 7

5.0

Sulfur _________ .

Air-drying loss ___ -._

Btu ____________ .

Percent 

. ____ 0. 7

.... ___ 3. 8

.... ___ 12,880

The U.S. Bureau of Mines in cooperation with the Oklahoma 

Geological Survey has conducted experiments to determine the coking 

properties of Henryetta coal when used alone and when blended with 

Lower Hartshorne coal from Sebastian County, Ark. Two analyses 

on a dry basis of 900°C cokes that were produced are as follows (Davis 

and Eeynolds, 1941, table 3):

Volatile matterFixed carbon. _.

Sulfur.

100 percent 

Henryetta 

coal 

(percent)

1.4

90.0

8.6

1.8

80 percent 

Henryetta coal 

and 

SO percent 

Lower Hartshorne coal 

(percent)

1.8

89.7

8.5

1.8

Btu---_._ __________________________.___. 13,180 13,230

Henryetta coal does not form a coke so strong as that obtained from 

the eastern coal customarily used, but it is probably suitable for making blast-furnace coke. A blend containing 20 percent low-volatile coal 

from the Lower Hartshorne bed, however, produces a coke that has 

greatly improved strength. The low softening temperature of the ash 

makes the coke unsuitable for uses where clinker is a detriment, but 

it is not disadvantageous for use in the blast furnace.

On the basis of mapping and exploration as of January 1,1952, the 

remaining resources in the Henryetta bed as determined by Dunham 

and Trumbull (1955, p. 209) totaled 271 million tons, all of which is
G38 CONTRIBUTIONS TO ECONOMIC GEOLOGY

less than 1,000 feet below the surface. Of this total, 206 million tons is 

in parts of the bed 28-42 inches thick. About half of the total is readily 

recoverable. Dunham and Trumbull (1955, p. 211) also discussed 

several small areas where the Henryetta and Morris beds are suitable 

for strip mining.

SOUTHERN PART OP THE OKLAHOMA FIEU>, COAl^, PITTSBURG, 

ATOKA, LATIMER, AN1> LEFLORE COUNTIES

Coal of coking quality occurs in the southern part of the Oklahoma 

field (fig. 1, loc. 20) in an east-west belt extending through Coal, Pittsburg, Atoka, Latimer, Haskell, Le Flore, and Sequoyah Counties 

(Thorn and Rose, 1935; Hendricks, 1937,1939; Dane and others, 1938; 

Oakes and Knechtel, 1948; Knechtel, 1937, 1949). The coal-bearing 

rocks in the southern part of the Oklahoma field are of Pennsylvanian 

age and locally contain at least seven workable coal beds, of which the 

most important are the Lower and Upper Hartshorne and the McAlester beds. Many other beds are present, but each is generally less 

than 12 inches thick.

The Lower Hartshorne coal lies near the middle of the Hartshorne 

Sandstone, which includes interbedded shale and is 50-500 feet thick. 

The coal bed ranges in thickness from 2^ to 6 feet and averages 4 

feet where mined. The coal bed is free of partings in some places and 

contains as many as four partings in other places. Generally these 

partings are composed of pyrite or mineral charcoal and individually 

are seldom more than a fraction of an inch thick.

The Upper Hartshorne coal lies just above the base of the McAlester 

Shale, which overlies the Hartshorne Sandstone. The McAlester Shale 

is composed predominantly of dark shale, 1,200 to 2,800 feet thick. The 

Upper Hartshorne coal ranges in thickness from 1 foot 8 inches to 

5 feet 7 inches and averages about 3 feet. The bed generally contains 

no partings, but locally one to three partings, each a fraction of an inch 

thick, may be present.

The McAlester coal occurs just above the middle of the McAlester 

Shale. It ranges in thickness from 1 foot 8 inches to 4 feet and, where 

mined, averages 3% feet. Prospecting has shown, however, that the 

McAlester bed is less than 2i£ feet thick throughout much of the area. 

As many as seven partings may be present in the bed, but most of 

them are very thin bands of pyrite that can be easily removed by 

washing.

East and south of Vian and south and southeast of Sallisaw, Sequoyah County, are several large strip mines that produce low-volatile 

bituminous coal. Trumbull (1957, p. 348) referred to the coal south
COKING-COAL DEPOSITS, WESTERN UNITED STATES G39

and southeast of Sallisaw as the Stigler coal, and suggested that it may 

be correlative with the McAlester coal.

The structure of the southern part of the Oklahoma coal field consists principally of a series of eastward- and northeastward-trending 

folds. The synclines are broad and flat, but the anticlines are tightly 

folded, and the dip of the rocks, which ranges from 5° to 90°, has to a 

great extent determined the areas where mining has taken place. 

Where the dips are less than 20°, mining operations'have been extensive, but the more steeply dipping coal beds have been worked only 

locally.

Thrust faults having displacements that range from a few feet to 

more than 1,000 feet also trend generally eastward or northeastward 

across the coal field, and some can be traced for several miles. Normal 

faults, some of which have large displacements, are common in the 

eastern part of the coal field near the Arkansas State line.

The coal in the southern part of the Oklahoma field increases in 

rank from high-volatile C bituminous in the southwesternmost counties 

to low-volatile bituminous in the easternmost counties near the Arkansas line. Because of this regional gradation and because differences 

in rank within a single bed may be greater than differences in rank of 

two separate beds, the composition of the coal can be shown only by 

many analyses (U.S. Bur. Mines, 1928a, p. 13-29).

Between 1880 and 1908, coke was manufactured in the McAlester 

district, in the western part of the southern Oklahoma field, from 

high-volatile bituminous coal produced from the McAlester and Hartshorne beds. Only washed slack coal, however, could be used satisfactorily. An analysis of coke produced from the washed coal is as 

follows (Hendricks and others, 1939, pt.l, p. 81):

Percent

Volatile matter_______ 2. 59 

Carbon ____________ 85. 33 

Ash ______________ 11.12

Percent

Phosphorus ____________ 0.04 

Sulfur _______________ 1.75

At Howe, in the eastern part of the field, 40 ovens were used from 

1900 to 1905 for the manufacture of coke from low-volatile coal produced from the Lower Hartshorne bed. The quality of the coke is 

said to have been good, and the lack of an adequate market is given 

as the principal reason for abandonment of the ovens. Low-volatile 

Lower Hartshorne coal cannot be coked alone at the present time, 

however, because it tends to expand and will ruin the walls of a modern byproduct oven.

Coking experiments on samples of McAlester coal from Pittsburg, 

County and Lower Hartshorne coal from Le Flore County, Okla.,
G40

yielded 900 °C coke having compositions as follows, calculated on a dry 

basis (Davis and Keynolds, 1942, table 4):

100 percent 

McAlester 

coat

0.76

1.90

13, 480 

2. 2

90.8

7.0

.4

70 percent 

McAlester 

coal and 

SO percent 

Lower 

Hartshorne 

coal

0.82

1. 93

13, 440

1.8

91. 1

7.1

.8

Apparent specific gravity.--.-- ________________

True specific gravity____________________________

Btu_____________________________ 

Volatile matter.______________________.percent..

Fixed carbon...._________________________do.___

Ash_.___ ________-_--_-._--_____ .do _

Sulfur. __._____________________do. 

The high-volatile McAlester coal alone yields a very weak coke, but 

blends incorporating 30 percent low-volatile Lower Hartshorne coal 

yield a coke with increased specific gravity, size, and stability. The 

sulfur content is thereby increased, because of the high sulfur content 

of the Lower Hartshorne coal, but it is still below the maximum limit 

set for blast-furnace coke. The low softening temperature of the ash 

contributed by both coals renders the coke unsuitable for some uses, 

but will not affect its performance in a blast furnace.

Low-volatile coal from eastern Oklahoma has been used in coke ovens 

at Provo, Utah, Fontana, Calif., and Daingerfield, Tex., for blending 

with high-volatile coals to improve the physical properties of the coke 

produced.

As estimated by Trumbull (1957, p. 309), the remaining resources 

of coal in Oklahoma, based on exploration and mapping as of January 1,1953, totaled 3,245 million tons, which includes beds 14 inches 

or more thick and less than 3,000 feet below the surface. This tonnage 

is subdivided by rank as follows:

Millions of 

Rank short tons

High-volatile bituminous __ _ _ ______________ 2,114

Medium-volatile bituminous_________________________________ 430

Low-volatile bituminous____________________________ 701

(Total_______ 3,245

All the strongly coking low- and medium-volatile bituminous coal is 

directly useful in the manufacture of coke and in the preparation of 

coking-coal blends. Much of the high-volatile bituminous coal is useful as base stock in the preparation of coking-coal blends. The Trumbull report includes a detailed classification of the resources by townships, beds, thickness of beds, rank, and other resource categories.
COKING-COAL DEPOSITS, WESTERN UNITED STATES G41

WESTERN ARKANSAS FIELD, SEBASTIAN, CRAWFORI>, FRANKLIN, 

IA)GAN, SCOTT, JOHNSON, POPE, AND YELL, COUNTIES

The western Arkansas coal field (fig. 1, loc. 21) is an eastward extension of the eastern Oklahoma field and is underlain by rocks of the 

same age. These rocks are subdivided into named units, which are 

equivalent, with a few minor exceptions, to units of the same names 

in Oklahoma. The geology of the field has been described by Collier 

(1907) and by Hendricks and Parks (1937), and the occurrence and 

distribution of coal by Haley (1960).

Three coal beds the Lower Hartshorne, the Charleston, and the 

Paris are of commercial importance in the Arkansas field, and many 

other beds, each less than 18 inches thick, are present. The Lower 

Hartshorne bed, which is in the lower part of the McAlester Shale, is 

generally correlated with the Lower Hartshorne bed in Oklahoma. 

This bed is 2-7 feet thick and is the most important coal in Arkansas. 

Partings are typically 1-6 inches thick but locally increase to as much 

as 3 feet thick. In some places only one bench of coal is mined.

In the extreme southwest part of the Arkansas coal field, a local 

coal bed correlated with the Upper Hartshorne of Oklahoma lies 40- 

90 feet above the Lower Hartshorne bed, but it is a thin bony coal and 

has little or no commercial value.

The Savanna Sandstone, overlying the McAlester Shale, consists 

of alternating beds of sandstone and shale and contains the other two 

workable coal beds in the Arkansas field. The lower bed, the Charleston, is generally 14-20 inches thick, and the upper bed, the Paris, is 

18 inches thick, increasing locally to 34 inches.

The Arkansas coal field trends east-west and lies between the Boston 

Mountains on the north and the Ouachita Mountains on the south. 

The two mountain areas were formed by different types of earth 

movement, and these differences are reflected in the structure on the 

north and south sides of the coal field. In the Boston Mountains 

the rocks dip gently southward and are broken by high-angle normal 

faults. The coal-bearing rocks on the north side of the coal field 

conform to this pattern. In general they dip less than 10° S. and are 

broken by high-angle normal faults. South-dipping normal faults, 

which are common in this part of the coal field, have displacements 

of as much as 2,500 feet. North-dipping normal faults, which are 

less common, have displacements of as much as 500 feet. In the 

Ouachita Mountains the rocks have been deformed by thrust faults 

and by folds with steeply dipping and locally overturned, limbs. On 

the south side of the Arkansas coal field, therefore, the coal-bearing 

rocks are folded and locally thrust faulted.

The coal in the Arkansas field increases in rank from low-volatile 

bituminous in the western part of the field near the Oklahoma State
G42 CONTRIBUTIONS TO ECONOMIC GEOLOGY

line to semianthracite in the eastern part of the field. The approximate range in composition of the coal as shown by many as-received 

analyses is as follows:

Range in

composition

(percent)

Moisture___________ 2-4 

Volatile matter_______ 12-20 

Fixed carbon________ 70-80

Range in

composition

(percent)

Ash_________________ 3-10 

Sulfur_______________ . 7-2.6

Low-volatile coal from the Arkansas field, when blended with highvolatile coal, produces a coke with improved physical properties, particularly increased strength. This coal is shipped to California, Utah, 

and Colorado for use in blends with western high-volatile coals.

As estimated by Haley (1960, p. T95), the original resources of coal 

in western Arkansas in beds 14 inches or more thick and less than 

3,000 feet below the surface totaled 2,272 million tons. The original 

resources include 1,816 million tons of low-volatile bituminous coal 

and 456 million tons of semianthracite. The strongly coking lowvolatile bituminous coal is used in blends with lower rank coal as the 

base stock to improve the quality of the coke produced, and small 

amounts of semianthracite may be used in the same way. The Haley 

report includes a detailed classification of resources by counties, beds, 

thickness of beds, thickness of overburden, rank, and other resource 

categories.

CONCLUSION

Although the 21 localities in the West, described above, collectively 

contain large resources of coal having coking properties, only a few 

localities contain adequate resources of the better quality coal necessary 

for the production of metallurgical coke. The Sunnyside-Castlegate 

field, Utah, the Eaton Mesa region, Colorado-New Mexico, the Somerset-Crested Butte-Carbondale field, Colorado, and the southeast Oklahoma and Arkansas fields contain most of the resources of the better 

quality coal and account for most of the western production of coking 

coal. Several other fields, notably the Wilkeson-Carbonado-Fairfax 

and Eoslyn fields, Washington, and the Kemmerer-Willow Creek field, 

Wyoming, contain adequate resources of coal that, by washing and 

blending, can be made to yield coke approaching in quality that made 

from coal obtained in the main producing fields listed above. The 

remaining fields, for the most part, yield coal with weak coking 

properties, or they contain small resources. These fields, however, 

may be advantageously located for consumers whose requirements 

could be served by the quality and quantity of coal available.

The practice of washing and blending coal to improve the quality 

of the resulting coke is employed at most coke-producing centers in
COKING-COAL DEPOSITS, WESTERN UNITED STATES G43

, the West. Materials typically added to the western coals to improve 

( the quality of the blends include low-volatile bituminous coal, petroleum coke, and a char made by the low-temperature distillation of 

local coal. Of them, the low-volatile bituminous coal is most desirable. 

Unfortunately, the West contains insignificant resources of suitable 

low-volatile bituminous coal, and the most convenient assured supply 

is from the large resources of southeastern Oklahoma and western 

Arkansas fields. Coke produced from blends of western coals does 

not equal the best eastern coke in quality, but with a growing market 

' for industrial products in the West, blends utilizing the better quality 

western coal as base stock continue to offer the best opportunity for 

reducing transportation and other costs below those required for eastern coke.

The development of the large resources of western coking coal for 

use in iron and steel manufacturing is largely dependent, therefore, 

upon technological advances in washing, blending, and coke manufacturing procedures, and in the design and operation of blast furnaces 

to utilize the available product effectively.

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G44 CONTRIBUTIONS TO ECONOMIC GEOLOGY

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 1939, Geology and fuel resources of the southern part of the Oklahoma coal

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 1924, Geological investigation of the coal fields of Skagit County, 

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 1959, Geology of the Huerfano Park area, Huerfano and Custer Counties, 

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 1961, Coal resources of the Trinidad coal field in Huerfano and Las

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G46 CONTRIBUTIONS TO ECONOMIC GEOLOGY

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 1964b, Geology of the Chimney Rock quadrangle, Montana: U.S. Geol. 

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COKING-COAL DEPOSITS, WESTERN UNITED STATES G47

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 1910, The southern part of the Rock Springs coal field, Sweetwater County, 

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 1952, Coal deposit, Coal Creek district, Gunnison County, Colorado: U.S.

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 1928b, Analyses of Arkansas coals: U.S. Bur. Mines Tech. Paper 416, 26 p.

 1931a, Analyses of Wyoming coals: U.S. Bur. Mines Tech. Paper 484,159 p.

 1931b, Analyses of Washington coals: U.S. Bur. Mines Tech Paper 491, 

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 1932, Analyses of Montana coals: U.S. Bur. Mines Tech. Paper 529,119 p.
G48 CONTRIBUTIONS TO ECONOMIC GEOLOGY

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 1937, Analyses of Colorado coals: U.S. Bur. Mines Tech. Paper 574, 

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 1941, Analyses of Washington coals: U.S. Bur. Mines Tech. Paper 618 

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 1957, Geology and coal resources of the Starkville-Weston area, Las

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1951, Geology and coal resources of the Stonewall-Tercio area, Las Animas

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Zapp, A. D., 1949, Geology and coal resources of the Durango area, La Plata and

Montezuma Counties, Colorado: U.S. Geol. Survey Oil and Gas Inv. Prelim.

Map 109.

O