GEOLOGICAL SURVEY CIRCULAR 90 

March 1951 

COKING-COAL DEPOSITS 

OF 

THE WESTERN UNITED STATES 

By 

Louise R. Berryhill and Paul Averitt 
UNITED STATES DEPARTMENT OF THE INTERIOR 

Oscar L. Chapman, Secretary 

GEOLOGICAL SURVEY 

W. E. Wrather, Director 

Washington, D. C. 

Free on application to the Geological Survey, Washington 25, D. C. 
Introduction . . • . . . . . • • . . . . . . Origin, classification, and distribution 

·of coal. . . . . . • . . • . ••. 

Properties of coking coal. . . . . . . . . 

Coking-coal deposits . . . . . . . • . . 

Washington. . . . . • . . . . . . . . • 

Wilkeson -Ca,rbonado-Fairfax field, 

Pierce and King Counties, Wash. 

Roslyn field, Kittitas County, Wash .. 

Montana .....•..•.......... 

Great Falls field, Cascade, Fergus, 

and Chouteau Counties, Mont. . . • . Livingston-Trail Creek field, 

Gallatin and Park Counties, Mont .•• 

Electric field, Park County, Mont. 

Wyoming .......•.•...... Kemmerer -Willow Creek field, 

Lincoln County, Wyo. . . . . . . Rock Springs field, Sweetwater 

County, Wyo. . . . . . . . . . . . . 

Cambria field, Weston Cou:hty, Wyo. . . 

Utah .................. . Sunnyside-Castlegate field, Carbon 

County, Utah . . . . . . . . . . . Mount Pleasant field, Sanpete 

County, Utah . . . . . . . . . . . 

Kanab field, Iron County, Utah • 

Colorado .............. . 

Crested Butte field and vicinity, 

CONTENTS 

Page 

1 

1 

4 

5 

6 

6 . 6 

7 

7 

8 

8 

9 

9 

10 

10 

11 

Colorado--Continued. 

Delta, Gunnison, and Pitkin 

Counties, Colo. . . . . . . . Norwood ·field, Montrose and 

San Miguel Counties, Colo. . . 

Durango field, La Plata County, 

Colo ............... . 

Raton Mesa field, Huerfano and 

Las Animas Comities, Colo., 

and Colfax County, N. Mex. . 

New Mexico .............. . 

Monero field, Rio Arriba County, 

N.Mex ..•......•.. Cerrillos field, Santa Fe County, 

N.Mex ............ . 

Carthage field, Socorro County, 

N.Mex ............ . 

Oklahoma- Arkansas ...... . 

Henryetta district, Okmulgee 

County, Okla. . . . . . . . • . 

Southern part of the 01:1~ 1oma field, 

Coal, Pittsburg, Atoka, Latimer, 

and Le Flore Counties . . • • . • 

Western Arkansas field, Sebastian, 

Crawford, Franklin, Logan, 

Scott, Johnson, Pope, and Yell 

Counties. 

11 

12 

12 

12 Conclusion . . 

References. ·. 

ILLUSTRATIONS 

Figure 1. Coal fields of the western United States showing coking-coal localities . 

2. Heat value of coal of different ranks compared to proximate analyses 

TABLES 

Table 1. Classification of coals by rank . 

Page 

13 

14 

14 

14 

15 

15 

15 

16 

16 

16 

17 

18 

• 19 

• 19-20 

ii 

3 

2 
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EXPLANA ION ............ '-, I I ,---, ------- '---.t_, " 

-

Anthracite ·anthracite \ and semt 

~ 

.~ 

-

Low-volatile 

bituminous cool 

Medium- and high-volatile 

bituminous cool 

Subbituminous cool 

.. , 

' ,, r---, 

.. ~ \~ 

e ~' L----, JJ~() I ' 

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COKING-COAL LOCALITIES 

1. Wilkeson-Carbonado-Fairfax 

field 

2. Roslyn field 

3. Great Falls field 

4. Livingston-Trail Creek field 

5. Electric field 

6. Kemmerer-Willow Creek field 

7. Rock Springs field 

8. Cambria field 

9. Sunnyside-Castlegate field 

10. Mount Pleasant field 

11. Kanab field 

12. Crested Butte field and 

vicinity 

13. Norwood field 

14. D~rango field 

15. Raton Mesa field 

16. Monero field 

17. Cerrillos field 

18. Carthage field 

19. Henryetta district 

20. Southern part of the Oklahoma 

field 

21. Western Arkansas field 

IH1mmgJ Lignite 

0 200 4 00 600 Mil11 

Figure I.-Coal fields of the Wes·tern United States showing coking-:coal localities. 

\ 
COKING-COAL DEPOSITS OF THE.WESTERN UNITED STATES 

By Louise R. Berryhill and Paul Averitt 

INTRODUCTION 

The U. S. Geological Survey has been engaged 

in a study of the geology and coal resources of the 

western United States for many years, and theresults of this work have been presented in numerous 

volumes of the regular series of Annual Reports, 

Bulletins, Professional Papers, and Folios of the 

Geologic Atlas of the United States. In 1942, in 

response to the needs of the expanding western steel 

industry, the U. S. Geological Survey began a program of mapping and re-examination of areas in the 

West believed to contain coal of coking quality, and 

at the same time the U. S. Bureau of Mines began 

a program of drilling, sampling, and testing the 

coal in these areas. As a result of this cooperative 

effort much new information has been obtained. Because many of the earlier geologic reports on the 

western coal fields are now out of print, and because 

some of the more recent geologic studies of the areas 

containing coking coal are still in manuscript or preliminary form, this circular has been prepared tq 

summarize the information now available about the 

occurrence and reserves of coal in a number of 

seleCted localities in the western states where the 

coal has coking properties. Although emphasis is 

placed primarily on the geology of the coal deposits, 

references to publications concerned with the technological aspects of coking coal are cited where appropriate. 

The analyses of coal and generalized statements 

of coking properties included in this circular are 

based chiefly on information contained in publications 

of the U. S. Bureau of Mines. Data included in the 

bulletins of the Washington Geological Survey and 

in the mineral reports of the Oklahoma Geological 

Survey have also been abstracted to provide a summary of the occurrences of coking coal in these 

states. 

ORIGIN, ;CLASSIFICATION, AND DISTRIBUTION 

OF COAL 

Coal is composed of ancient plants and plant 

fragments that accumulated slowly on the floors of 

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 development 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 time. 

1 

During the process of compaction and coalification 

the beds of plant material undergo a series of physical 

and chemical changes, which, in general, result in a 

reduction of the amounts of moisture and volatile 

matter present, and a corresponding increase in the 

amounts of fixed carbon and heat value. The relative 

amount of ehange 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, 

as shown in table 1, which is a reproduction of the 

standard classification used in the United States 

(Amer. Soc. Testing Materials, 1939, pp. 1-6). 

Figure 2 shows graphically the relation between the 

heat value, moisture, volatile matter, and fixed 

carbon for the various ranks of coal defined in table 1. 

. Consider~bly more than half of all coal used in 

the manufacture of coke is of high-volatile A bituminous rank, followed in order of abundance of use 

by low-volati~e and medium-volatile bituminous ranks. 

Coal-bearing rocks are widely distributed west of 

the Mississippi River, as shown by figure 1, which 

also shows the distribution by rank. On a simple 

tonnage basis this area contains 70 percent of the 

total reserves of the United States, of which the 

larger part is of lignite, subbituminous,· and highvolatile C and B bituminous ranks, and is thus generally unsuitable for the manufacture of coke. By 

contrast, the area east of the Mississippi River 

contains 30 percent of the total United States reserves, 

all of which is of bituminous or anthracitic rank. A 

hu·ge part of the eastern bituminous coal reserves have 

· cokina orooerties. This geographic distribution of 

high- and low-rank coal is due in part to differences 

in age. Coal east of the Mississippi River, and in 

Iowa, Kansas, Missouri, Oklahoma, Arkansas, and 

parts of Texas, is of Pennsylvanian age. On the other 

hand, the coal in the Rocky Mountain and Pacific Coast 

regions is of Cretaceous or Tertiary age. Only in 

areas of mountain building and igneous activity, as 

locally in Montana, Wyoming, Colorado, New Mexico, 

Utah, and Washington, has the younger coal in the 

West reached bituminous or occasionally anthracitic 

rank. 

The best metallurgical coke is made from highvolatile A or medium-volatile bituminous coal, or from 

blends of high- and low-volatile bituminous coal. 

Although the West possesses comparatively small 

reserves of coal of these ranks ·suitable for manufacturing coke, at least 21localities in the West are 

known to contain coal that has coking properties. 

Several of these localities produce most of the coal 

used in the western steel industry. The growing 

industrialization of the West, and the accompanying 
Table I. Classification of coals by ranka 

Legend: F.C. == Fixed.Carbon. V .M. - Volatile Matter. Btu. - British thermal units. 

I Limits of Fixed Carbon or Requisite Physical Class Group Btu. Mineral-Matter-Free 

I Basis Properties 

1. Meta-anthracite ................. Dry F .C .• 98 per cent or more {Dry V.M., 2 per cent or less) 

2. Anthracite ...................... Dry F .C., 92 per cent or more 

I. Anthracitic 

and less than 98 per cent 

{Dry V.M.,8 per cent or less 

and more than 2 per cent) 

3. Semianthracite .................. Dry F .C., 86 per cent or more and less than 92 per cent 

N onagglomerating b..-

(Dry V .M., 14 per cent or less and more than 8 per cent) · 

1. Low volatile bituminous coal. ... Dry F .C., 78 per cent or more and less than 86 per cent 

{Dry V.M., 22 per cent or less and more than 14 per 

cen\) 

2. Medium volatile bituminous coal. Dry F .C., 69 per cent or more and less than 78 per cent 

(Dry V.M., 31 per cent or less and more than 22 per 

II. Bituminousd 

cent) 

3. Hil:!h volatile A bituminous coal. Dry F.C., less than 69 per cent 

(Dry V.M., more than 31 per cent); and moistc Btu., 

14,()008 or more 

4. High volatile B bituminous coal. Moistc Btu., 13,000 or more and less than 14,000C 

5. High volatile C bituminous coal. Moist Btu., 11,000 or more and less than 13,oooe 

Either agglomerating or non weathering/ 

1. Subbituminous A coal. .......... Moist Btu., 11,000 or more Both weathering and 

and less than 13,00(1 nonagglomerating 

III. Subbituminous 2. Subbituminous B coal. .......... Moist Btu., 9500 or more and 

less than 11,000' 

3. Subbituminous C coal. .......... Moist Btu., 8300 or more and 

less than 95ooe 

I 

IV. Lignitic 11. Lignite ......................... Moist Btu., less than 8300 Consolidated 

2. Brown coal ..................... ·Moist Btu., less than 8300 Unconsolidated 

a This classification does not include a few coals which haveunusual physical and chemical properties and which come within the limits of fixed carbon or Btu. of the high-vola.tile bituminous and subbituminous ranks. All of these coals 

either contain less than 48 per cent dry, mineral-matter-free fixed carbon or have more than 15,500 moist, mineral-matterfree Btu. 

b If agglomerating, classify in low-volatile group of the bituminous class. c Moist Btu. refers to coal containing its natural bed moisture but not including visible water on the surface of the 

coal. 

d It is recognized that there may be noncaking varieties in each group of the bituminous class. • Coals having 69 per cent or more fixed carbon on the dry, mineral-matter-free basis shall be classified according to 

fixed carbon, regardless of Btu. . 1 There are three varieties of coal in the high-volatile C bituminous coal group, namely, Variety 1, agglomerating and nonweathering; Variety 2, agglomerating and weathering; Variety 3, nonagglomerating and nonweathering. 

2 
B.t.u. 

14,000 

12,000 

10,000 

8,000 

6,000 

4,000 

~ 

2,000 :~ 

...J 

0 

Percent 

100 

80 

60 

40 

20 

0 

/ 

I 

I 

I 

I 

I 

I 

,I 

..... -----

...... ...... r--....... ... _~ 

,/ 

~--------~~~"'--VA----~~----~~--~~~----~~--~~----~~----4~----~~----~/~ / 

Figure 2.- Heat value of coal of different ranks compared to proximate analyses. 

Upper diagram: Comparative heat value of typical samples of the several ranks of coal, computed on . 

samples as received, on the ash-free basis. Lower diagram: Variation in the fixed carbon, volatile matter, and 

moisture of samples used in upper diagram, computed on samples as received, on the ash-free basis. 

3 
general increase in energy consumption thus place 

special emphasis on the desirability of more complete 

knowledge of wester:o resources of coking. coal. 

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 semi-liquid during destructive distillation. Once formed·, coke is infusible, more or _less 

friable, porous, and has a dark to metallic gray 

luster. Many bituminous coals will coke or fuse when 

heated in a closed furance, but only those coals that 

produce coke with a specific range of chemical and 

physical properties suitable for metallurgical and 

other industrial uses can be considered coking coals. 

It has not been possible as yet to devise a set of 

standards for the identification of a good coking coal 

by its chemical composition or physical properties. 

Rank is not the only criterion, as many coals of apparently 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 ingredi-ents of 

coal are recognized as generally influencing coking 

properties. Most bituminous coals, for example, 

contain bright, vitreous bands that represent the 

coalified trunks and limbs of plants and are known as 

vitrain. The best -coking ingredients occur within the 

vitrain bands, which are present in abundance in good 

coking coals. Fusain, the ingredient 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 within certain known limits will coke, but if 

too high or too low a percentage of oxygen is present, 

the coal will not coke. The presence of hydrogen in 

excess also has been shown to decrease the coke yield 

of coal. 

A good coking coal, when subjected to a uniformly 

increasing temperature, fuses or softens generally 

between 572° and 752° F. Gases of decomposition 

are formed at the fusing temperature, or slightly 

higher, causing the mass to become cellular and 

somewhat swollen. Viscosity increases until the 

mass becomes practically rigid before reaching a 

temperature of 842° F. Changes in structure continue 

to occur because of devolatilization, even after the 

coke has reached red heat, and the evolving of gases 

continues long after the mass has become rigid 

(Rose, 192'7, pp. 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 or from chars 

formed from coals that do not· fuse under coking 

conditions. The coking qualities of most coals can 

be improved by washing to remove ash and sulfur, 

or 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 

noncoking ingredients, such as anthracite fines, 

petroleum coke, or low-temperature char, which 

greatly improve the qualities of the resulting coke. 4 

Under certain circumstances natural coke may be 

produced in coal beds penetrated or affected by 

igneous intrusions. 

The standards that a coke must meet vary according 'to the purpose for which it is intended. Physical 

characteristics and the included impurities largely 

determine the value of coke as a fuel in particular 

industrial processes. On the basis of its principal 

uses coke may be classified as blast-furnace coke, 

foundry coke, water-gas coke, and domestic 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 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 industry the requirements are as follows (Rose, 1927, pp. 631-636): 

Maximum percentages 

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

.Sulfur ....•.•.....•................•...... 1. 3 

Phosphorus (for acid Bessemer iron) ........ 0. 01 

In addition, a coke of medium density is usually preferred for use in blast furnaces, and the optimum size 

of the individual pieces of coke should range between 

2 and 4 inches in diameter. 

Standards of strength and ash content are somewhat lower for coke intended for nonferrous smelting 

in the blast furnace. An increasingly high proportion 

of nonferrous metal, however, comes to the smelter 

in the form of finely ground concentrates that are 

more easily handled in a reverberatory furnace, which 

requires no coke. Since 1910 the blast furnace, although still used to some extent in lead smelting, 

has been gradually replaced by the reverberatory 

furnace in copper smelting. 

Foundry coke is used only to provide heat to melt 

the metal, and for this purpose the requirements are 

chiefly purity, large size, good strength, and a 

minimum reactivity with carbon dioxide gas. 

Water -gas coke must have a maximum ash content 

of no more than 6 percent, because the clinker and 

its removal present serious operating problems in this 

industry. The fusing temperature of the ash should 

range between 2300° a,nd 2500° F. , and the sulfur 

content should be low. A strong coke of uniform size 

is desirable for use in mapufacturing water gas .. 

Coke is an important source of fuel for smokeless 

domestic heating, as only a small proportion of the 

original volatile matter remains after destructive 

distillation. Coke used for domestic heating is, in 

general, not required to meet as exacting standards 

as that produced for industrial purposes. Too coke 

should be dense and have an ash content that ranges 

between 8 and 10 percent. A fusing temperature of 

2500° F. or more is desirable for the ash. Assuming 

optimum conditions such as an easily available supply 

of coal suitable for the production of a particular coke, 

the above standards are desirable for each type of 

coke. Necessity in wartime and in areas with limited 

coal reserves has shown, however, that by blending 

and by adopting special metallurgical processes, coke 

manufactured frorp. coal of seemingly inferior quality 

can often be used satisfactorily for many pu;rposes, 
even for the production of iron and steel. The selection of a coal for coking is, therefore, determined 

in part by economic considerations, and the demand 

for coke having certa1n physical properties is balanced 

against the availability of various coals that separately 

or in blends can be prepared to yield cqke having these 

properties. In the western United States, the cost 

of shipping eastern coal is weighed against the cost 

of cleaning, blending, and using local coal. A decision 

based in part upon freight rates becomes one that the 

individual user of coking coal must make, depending 

upon his location and needs, and the characteristics 

of nearby coal deposits. 

COKING-COAL DEPOSITS 

Until recently, the West has been remote from 

population centers and the consequent industrial 

and domestic demands for coke. In addition, the 

limited reserves of low- and medium-volatile bituminous coal throughout the West have restricted the 

development of a large coking industry. The expansion 

of manufacturing and industry in the West during 

World War II, however, and the desirability.of the 

post-war continuation of these activities have emphasized 

the need for coal that will best serve the West for 

coking and allied purposes, such as the growing need 

in some urban areas for a smokeless domestic fuel. 

At several localities the western high-volatile 

bituminous coal will form a coke that performs 

satisfactorily in blast furnaces and foundries. It is, 

however, somewhat inferior in porosity, size, and 

strength to the coke produced from eastern coal. At 

other localities in the West the coal has potential use 

in the manufacture of coke, depending in part upon 

improved processing and coking practices, or specially adapted metallurgical processes. A few other 

areas contain coal with coking properties, but are 

considerea of little or no economic importance because 

of impurity of the coal, difficult mining conditions, 

or exhaustion of reserves. 

The important localities in the West that produce 

coking coal are the Raton Mesa field, ColoradoNew Mexico, the Sunnyside-Castlegate field, Utah, 

the Crested Butte field, Colorado, and the coal fields 

in southern Oklahoma and western Arkansas. i The 

highest quality western coke, satisfactory for all 

metallurgical purposes, is made from the coal from 

the Raton Mesa field blended with low-volatile coal. 

As this field lies on the eastern side of the Rocky 

Mountains, it is relatively remote from the several 

main 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, in spite of being brittle and containing 

too high a percentage of small.sizes, is used successfully in blast furnaces for ferrous smelting. As a 

result, it has become the standard b~ 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 by 

virtue of its position west of the Rocky Mountains, is 

the source of much of the coke used on the West Coast. 

5 

Most of the other areas in the West containing 

coking coal are no longer used as sources of metallurgical coke, though at various times in the past, 

coal from many of these areas has been coked in 

beehive ovens and used in nonferrous smelters and 

refineries. With more restrictive specifications, 

and with improvements in transportation, however, 

the superior cokes made from eastern coal and from 

the coal produced in the Raton Mesa, SunnysideCastlegate, and Crested Butte fields in the West were 

able to compete directly with the local products. 

The growing western iron and steel industry would 

be greatly benefited, however, if coal from some of 

the more advantageously located coking-coal 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, but even with the added processing costs, 

the utilization of the local coal might eventually prove 

to be more economical than shipping and processing 

coal from distant sources. 

As many economic and technologic factors are 

involved in the definition of 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 their reserves. The accompanying ]nap 

(fig. 1), however, shows 21 localities in the West 

where coal having coking properties has been obtained, 

and the available information regarding. the occurrence 

of coal at each locality, the properties of the coke 

produced, and the reserves of coal is summarized in 

the following paragraphs. 

In discussing reserves 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 reserve estimates are based. 

Measured reserves are those based on observations 

about one-half mile apart, or which lie within onehalf mile of a well-established, continuous outcrop. 

Indicated reserves are those based on observations 

about 1 ar 1! miles apart, or which lie no more than 

2 miles from a well-established, continuous outcrop. 

Inferred reserves 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 inferr.ed lies more than 2 miles from the 

outcrop. 

In reporting tonnages of coal reserves, the term 

original reserves refers to total reserves in the 

ground before mining began, and does not take into 

account past production and losses or future losses. 

Remaining reserves are unmined reserves 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 reserves, but 

no allowance has been made for future losses. Where 

allowance has been made for past production and 

losses and future losses, the term recoverable 

reserves is used. 
Washington 

The important deposits of coking coal in Washington are in the Wi~son-Carbonado-Fairfax field 

in Pierce and King Counties on the western slope 

of the Cascade Mountains, and in the Roslyn field 

in Kittitas County on the eastern slope of the Cascade 

Mountains. Smaller deposits of coal that may be of 

coking quality extend along the western slope of the 

Cascade Mountains through Skagit and Whatcom 

Counties nearly to the northern boundary of the State. 

The coking properties of the coal in Pierce, King, 

Skagit, and Whatcom Counties appear to be due to 

the physical and chemical changes that resulted from 

the close folding of the sedimentary rocks containing 

the coal beds. In the Roslyn field the coal-bearing 

rocks are less sharply folded, and coal that is suitable 

for coking occurs only in the northwestern part of the 

field. In this area the coal-bearing rocks have been 

somewhat more altered than the rocks in the north .. 

eastern part of the field, which contains noncoking 

coal. Alteration of the rocks alone, however, does 

not appear to be sufficient to account for the coking 

or noncoking properties of the coal in this field. Differences in the composition of the coal are indicated 

by the higher agglutinating value and lower ash content 

of the coal in the northwestern part of the field as 

compared with the coal in the southeastern part. 

Wilkeson-Carbonado-Fairfax field, Pierce and King 

Counties, Washington (Loc. 1). --Most of the coking 

coal produced on the Pacific coast is obtained from the 

Wilkeson-Carbonado-Fairfax fieldl in Pierce and King 

Counties, Washington (Daniels, 1914; Warren and 

others, 1945). · The coal beds in this field are in the 

Puget group of Eocene age, which is a sequence of 

interbedded sandstone and shale, 10,000 to 15,000 

feet thick. Many coal beds of varied extent and 

thickness are present, but onl3• 17 are known to be 

workable. The Puget group 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, and 

the Burnett formation, the youngest formation in the 

group, includes only a few beds of commercial value, 

which yield coal of lower quality than the coal from 

the Carbonado formation. 

The workable coal beds in the Carbonado formation are individually from 3 to 15 feet thick, but 

are divided by partings. into benches, each of which 

is usually 2 to 4 feet thick. The partings between 

the benches consist of shale, clay, and bone, and 

each parting is from a fraction of an inch to one foot 

thick. 

The principal structure of the field is an asymmetrical, 

northward plunging anticline, having an average dip 

of 60° on the east limb and steeper dips ranging from 

60° to 85° on the west. The strongly folded west 

limb contains a series of synclines, or.basins, in 

which most of the coal mines are located. Faults are 

numerous, and both overthrust faults associated with 

the folding, and younger normal faults cut the coalbearing rocks with displacements ranging from a few 

feet to nearly 2, 000 feet. The structure of the coal 

field is further complicated by the presence of dikes 

and flows of igneous rock, the heat from which has 

altered the adjoining sedimentary· rocks and coal beds. 6 

The coal varies widely in rank according to the 

amount of deformation or alteration it has undergone, 

but analyses on an as-received basis range in general 

as follows (Daniels, 1941, p. 16): 

Moisture •.....•. ." •..•••.. 

Volatile matter .......•..• 

Fixed carbon ••..•••...•.• 

Ash .....•..••.•••.•••••.• 

Sulfur ••.•.••...•.•.•..•.• 

Phosphorus .•..•....•.•••• 

Percent 

4. 0- 2. 0 

33.0- 20.0 

51.0- 63.0 

12.0- 15.0 

o. 6- a. 8 

0. 05- 0. 1 

The coal from this area .can be used in byproduct 

ovens and will yield a coke that can be used for most 

purposes. Coke manufactured during the period 

1915-1934 ranged between 12. 7 and 26. 6 percent in 

ash content, and 0. 25 and 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 

with the following properties (Yancey and others, 

1943): 

Apparent specific gravity. . . . . . . . . . . . . . 0. 87 

True specific gravity. . . . . . . . . . . . . . . . . 1. 94 

Ash softening temperature ............. 2, 800° F~ plu""' 

B. t. u· ................................ 12, 620 ' 

Moisture .......................... . 

Volatile matter ......•..•............ 

Fixed carbon •........................ 

Ash .....•...•.••..•..•.••...•....•• 

Phosphorus ........................ . 

Sulfur .......................•...... 

Cell space ..............•.•.....•..• 

Coke yield ........................ . 

Percent 

1.0 

0.8 

87.0 

11.2 

0.69 

0.5 

55.2 

72. 1 

Tumbler and shatter tests: satisfactory for electrochemical and slectrometallurgical purposes; 

questionable for foundry and iron blast furnace. 

The phosphorus content of coal from the WilkesonCarbonado-Fairfax area is too high to meet therequirements of specialized industries; such as ferroalloy manufacturing, but blast-furnace and foundry 

operators might use some of the coke from this field 

by modifyinQ their standard operating practices. Within certain limits,. therefore, coke prepared from blendE' 

of Washington coal could be utilized successfully for 

purposes now served by coke from eastern states. 

As estimated by the operating companies in the 

area in 1940, the recoverable reserves of coking coal 

in the Wilkeson-Carbonado-Fairfax field were believed 

to be between 60 and 125 million net tons (Daniels, 

1941, p. 16). 

Rosl n field Kittitas Count Washin ton loc. 2). -· 

The Roslyn field in Kittitas County, ashington, which 

has been described by Saunders (1914), covers an area 

of about 40 square miles on the east slope of the Cascac' 

Mountains, approximately 75 miles east of·Tacoma. TT· 

coal beds are confined. to the upper 1, 000 to 1, 200 feet 

of the Roslyn formation, a sequence of sandstone and 

shale of Eocene age. This upper zone includes 10 

coal beds, each ranging in thickness from less than 2 

feet to 15 feet, but only four" of these beds have been mir· 
Of them, the Roslyn (No. 5) and the "Big Dirty" beds are the most important. 

The Roslyn coal "bed normally is 4 feet 6 inches 

thick, having an upper bench of coal 29 inches thick, 

a 4- to 6-inch parting of coal and shale, and .a lower 

bench of coal 20 inches thick. The bed is relatively 

uniform in thickness and has been worked throughout 

the entire area of the field. The "Big Dirty" bed is 

15 to 19 feet thick, but the workable coal is limited 

to a zone 5 to 6 feet thick in the lower part of the 

bed. This lower part is usually divided into two 

benches by a thin clay parting. 

The coal-bearing sediments in the Roslyn field 

dip toward the center· of a gentle, southeastward 

plunging syncline at angles of 10° to 30°. In general, 

the structure is simple, and the coal is mined with 

ease. 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, but for the mcst part, they do not 

interfere seriously with mining. The Roslyn formation is overlain and underlain by basalt, but no 

dikes are known to cut the sedimentary rocks, and. 

the coal is unaffected by igneous activity. 

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, pp. 42-43): 

Percent 

Moisture. . . . . . . • . . . . . . . . . . . • . . . . . 3. 5 

Volatile matter. . . . . . . • • . . . . . • . . . . . 37. 8 

Fixed carbon . . . . . . . . • . • . . . • • . . • . . . 46. 7 

Ash............................... 12.0 

Sulfur............................. Q3 

Air-drying loss.................... 1. 6 

B. t. u. • • • • • • • • • • • . • • • • • • . • • • . • • • 12 .• 630 

The average phosphorus content of four san;tples of 

coal from the Roslyn bed as determined by tests of 

the U. S. Bureau of Mines is 0. 66 percent (Yancey 

and others, 1943, p. S}. 

The agglutinating value of the coal in the Roslyn 

bed increases from the southeastern part of the field 

to the northwest. In addition, the ash content is somewhat lower in the northwestern part. In general, 

therefore, the coal in the northwestern part of the 

field is considered more suitable for use in making 

coke. Tests by the U. S. Bureau of Mines (Yancey 

and others, 1943}, indicated that coke made from 

100 percent Roslyn coal is somewhat fingery as 

compared with coke manufactured from coal produced 

in the field in Pierce and King Counties, or from 

blends of the two coals with petroleum coke. Furthermore, it tends to be weak in shatter and tumbler tests. 

and to have a high phosphorus conten~. · Roslyn coal 

forms excellent coke for domestic use, however, 

and is satisfactory for use in coking-coal blends. 

As estimated by Mr. Thomas Murphy, Manager 

of Coal Operations for the Northwestern Improvement 

Co. , the recoverable reserves· of coal in the Roslyn bed 

before minin~,,~re 64,068,000 tons. During the period 

7 

from 1886 to January 1, 1949, production from the 

bed has totaled 52, 324, 000 tons, leaving on January 1, 

1949, recoverable reserves of 11, 744, 000 tons. Only 

part of this total lies in the more favorable northwestern 

pai"t of the field. 

Montana 

Although Montana has large coal reserves, only 

three areas, all located in the central part of the 

State, contain coal that has coking properties. In 

the Livingston-Trail Creek field, Gallatin and Park 

Counties, the sedimentary rocks have been tightly 

folded and faulted, and as a result, part of the coal 

has coking properties. Similarly, in the Electric 

field, in Park County, the coal has coking properties 

because of the deformation to which the coal-bearing 

rocks have been subjected. In the Great Falls field, 

Cascade, Fergus, and Chouteau Counties, the rocks 

have only gentle dips and no alter~tion of the coal by 

earth movements or igneous activity has taken place. 

The coal in this field occurs in rocks of Lower 

Cretaceous age, however, and is older than·the coal 

in the Livingston-Trail Creek and Electric fields, 

which is of Upper Cretaceous age. 

Coal from these three Montana fields formerly 

was used in the production of coke. for local copper 

smelters. Coke is seldom used in cppper refining 

today, however, and as coke made from Montana 

coal is not of sufficiently high quality for use in other 

metallurgical processes without the adoption of special 

methods, no coal was being mined for coking purposes 

in Montana in 1949. 

Great Falls field Cascade Fer us and Chouteau 

Counties, Montana loc. . --T e Great Fa s coal 

field, in Cascade, Fergus, and Chouteau Counties, 

Montana, includes three adjacent areas of minable 

coal, which together cover a minimum of 334 square 

miles (Fisher, 1909}. The coal occurs about 60 feet 

above the base of the Kootenai formation, which consists 

of interbedded massive sandstone and shale of Lower 

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, is present 

throughout the field. Near Belt and Sand Coulee, 

where the coal has been mined extensively, it ranges 

typically between 4 and 9 feet in thickness, and is 

broken into two or three benches "by shale and bone 

partings, which must be removed. 'rhe 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. 

The coal-bearing rocks dip gently 3° to 5° NE., 

but may exhibit minor local undulations. In some places steeper dips present difficulties in mine 

haulage. Faults having displacements of 5 to 20 feet, 

and igneous rocks, principally basalt dikes, break 

the continuity of the coal-bearing rocks locally, but 

neither of these features causes any unusual mininc;J 

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_ 

Band C bituminous ranks. An analysis on the asreceived 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, pp. 42-43): 

Percent 

Moisture . . . . . . . . . . . . . . . . . . . . . . . . . 5. 9 

Volatile matter. . . . . . . . . . . . . . . . . . . • 32. 8 

Fixed carbon . . . . . . . . . • . . . . . . . . . . . 49. 3 

Ash •.............•............... 12.0 

Sulfur .....•.•.•......••......•...• 4. 0 

Air-drying loss.................... 2. 4 

B. t. u .........•............... 11,470 

Sulfur is present principally in the form of pyrite 

nodules, which range from the size of a pinhead to 

about 4 inches in diameter, the average being about 

1 inch. Some of these rtodules, together with much 

of the ash, can be elimirated by washing and jigging 

the coal. ' 

I 

I 

Only certain benche~ of the coal possess coking 

properties. The Anaconda Mining Co. formerly 

operated coke ovens at $elt, Montana, but abandoned 

them, in part because oif the difficulty and expense of 

separating coking from honcoking 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 

reserves of coal that can be c-lassed as measured and 

indicated, according to the definitions on page 5, 

total 308,820,000 tons. This coal is contained in 

several beds, each at least 24 inches thick, beneath 

no more than 500 feet of overburden. Some of these 

estimated original reserves have been depleted by 

mining, and th~ amount of coal remaining that is of 

coking quality can be ascertained only by actual 

tests; but the reserves are believed to be sufficient 

to supply moderate industrial demands that have somewhat lower standards for industrial coke. Additional 

information about the reserves of coal in the Great 

Falls field and other fields in Montana is contained 

in reports by Combo and others (1949, 1950). 

Livin ston-Trail Creek field, Gallatin and Park 

Counties, Montana loc. 4 . --The Livingston-Trail 

Creek coal field, in Gallatin and Park Counties, 

Montana, forms a narrow Y -shaped belt extending 

across three townships for a distance of approximately 

22 miles (Calvert, 1912, pp. 384-405). The coalbearing formation, composed predominantly of sandstone beds totaling 750_ to 900 feet in thickness, is at 

the base of the Montana group of Upper Cretaceous 

age. This unit is probably equivalent to the Eagle 

sandstone, which occurs in the lower part of the 

Montana group at other localities in the state. Coal 

of workable thickness occurs in three or four beds 

that individuaJ.ly range from 2 to 5 feet in thickness. 

Several partings of clay, shale, or bone separate 

the coal into benches, each of which usually contains 

1 to 3 feet of coal. 

The coal beds in this area are on the steeply 

dipping flanks of anticlinal folds and locally are broken 

by faults. Because the rocks normally dip between 

40° and 65°, and in some places are vertical or overturned, the coal is too deep for mining a short distance 

from the outcrops. Locally the coal has been crushed 

by differential mo'tfements in the overlying and underlying beds. 

8 

The coal ranges in rank according to the amount 

of deformation it has undergone, but in general it is of 

high-volatile A, B, or C bituminous rank. An analysis 

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

Anaconda mine at Storrs, Gallatin County, is as follows 

(U. S. Bur. Mines, 1932, pp. 48-49): 

Percent 

Moisture. . . . . . . . . . . . . . . . . . . . . . . . . . . 6. 3 

Volatile matter. . . . . . . . . . . . . . . . . . . . . . 32. 4 

Fixed carbon. . . . . . . . . . . . . . . . . . . . . . . . 45. 6 

Ash................................ 15.7 

Sulfur.............................. 0. 4 

Air -drying loss. . . . . . . . . . . . . . . . . . . . . 4. 5 

B. t. u ......................... _. .. .11, 460 

In the past, coal mined from several parts of 

this field has been washed and used for the manufacture 

of coke, and at one time 100 beehive ovens were in 

operation at Cokedale. The original coal reserves in 

the main bed in T. 2 S. , R. 8 E. , Montana principal 

meridian, were inferred to be 442, 500 tons, all presumaJ· 

of coking quality. All of the easily accessible coking 

coal in the field, however, is now. mined out. 

Electric field, Park County, Montana (loc. 5). --The 

Electric field, Park County, Montana, includes two 

small coal-producing areas·, which together cover 

less than 3 square miles. The coal-bearing rocks in 

this field lie in the lower part of the Montana group 

of Upper Cretaceous age and are believed to be 

equivalent to the Eagle sandstone. The coal occurs in 

a thick sequence of shale interbedded with sandstone in 

a stratigraphic interval of 300 feet. Three principal 

beds, which individually range in thickness from 3 to 

5 feet and locally contain thin partings of clay and 

sandstone, are known to be present. 

Mining conditions are difficult in the Electric field 

because of the complexity of the structure. The coalbearing rocks occur in two synclinal areas within a 

fault block that has been downdropped several thousand 

feet in relation to the surrounding area, so that the 

coal-bearing rocks on the e~st side of the fault block 

are in contact with pre-Cambrian crystalline rocks. 

The fault block itself has been cut by numerous normal 

and thrust faults. The sedimentary rocks lie in 

positions ranging from nearly horizontal to vertical, 

but tight folding is common, and steep dips prevail 

throughout most of the field. Beca1:1se of the faults 

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

considered minable by present standards. 

Igneous rocks are not uncommqn, but few have 

been encountered in the mine workings. They will 

present a more serious problem, however, as 

operations are continued southward to the vicinity of 

Electric Peak, which is the center of a system of 

radiating dikes and sills. 

The coal in this field is relatively high in rank 

because of the alteration and deformation to which it 

has been subjected. In general, the coal is of highvolatile A or medium-volatile bituminous rank, but 

locally it is semiantl').racite. Ar;. analysis on the asreceived basis of a sample of coal from the Aldridge 

mine at Aldridge, Park County, is as follows (U. S. 

Bur. Mines, 1932, pp. 54-55): 
Percent 

Moisture. . . . . . . . . . . • . . • . . . . . . 4. 0 

Volatile matter............... 22. 5 

Fixed carbon .... :. . . . . . . . . . . . 59. 3 

Ash .......................... 14.2 

Sulfur........................ 0. 6 

. Air .. drying loss............... 2. 7 

B. t. u. ••..•.••..••.•.•.•.• 12, 760 

Of the three coal beds in the Electric field, the 

uppermost has the strongest coking properties and 

is the only one that has been mined extensively. 

Locally, however, coal from the other two beds also 

is suitable for coking. Practically all the coal mined 

from this area in the past was used to manufacture 

coke, chiefly for the smelters at Anaconda and Butte. 

It is reported that the coke was of good quality, although the operators were unable to meet the requirements of those smelters for an ash content of less 

than 18 percent (Calvert, 1912, pp. 406-422). 

The original coal reserves of the Electric field 

in beds at least 3 feet thick, having overburdens of 

no more than 1, 000 feet, are inferred to have been 

20,834,670 tons. Because of the great number of 

faults in the field, and because of the scarcity of 

information about the coal underlying the centers of 

the two synclinal areas, none of the reserves can be 

classified as measured or indicated. The reserve 

estimate includes the coal in all three minable beds, 

and as only one is predominantly of coking quality, 

probably no more than one-third of this figure should 

be considered as representing the inferred cokingcoal reserves. Further allowance should be made 

for past production in the field and for losses in 

mining. , ' 

Wyoming 

The coal beds in Wyoming, which are of Cretaceous 

and Tertiary age, were deposited 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 essentially flat-lying. 

Because many of the coal beds have been subjected to 

little or no deformation, Wyoming, which has large 

coal reserves, contains mostly subbituminous coal 

and low-rank bituminous coal. Only in three areas 

in the State is the coal suitable for coke production. 

In the Rock Springs field, Sweetwater County, 

where the coal-bearing formations have been affected 

by the Rock Springs uplift, the lowermost coal bed, 

which is of Upper 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 Lower Cretaceous age that was mined 

formerly as a coking coal. The Willow Creek coal 

bed of Upper Cretaceous age in the KemmererWillow Creek field, Lincoln County, has coking 

properties, probably as a result of the rather close 

folding of the rocks. 

Kemmerer-Willow Creek field Lincoln Count , 

Wyoming loc. 6. --The coal field near Kemmerer 

in southwestern Wyoming, which has been described 

by Schultz (1914), comprises several areas of coalbearing rocks located in a long, narrow synclinal 

9 

belt that extends northwestward into Idaho. During 

1942-1943, a part of this belt 12 miles long, approximately 12 miles north of Kemmerer, was the subject 

of a cooperative survey by the U. S. Geological Survey 

and the U. S. Bureau of Mines to determine the quantity 

and quality of available coking coal (Andrews, 1944; 

Toenges and others, 1945) . 

Coal having coking properties in the KemmererWillow Creek area occurs in the Willow Creek and 

Kemmerer coal zones in the Frontier formation of 

Upper Cretaceous age. Higher in the section, coal 

generally unsuitable for making coke occurs in the 

Adaville formation, also of Upper Cretaceous age. 

Both the Willow Creek and the Kemmerer zones 

contain several closely spaced coal beds, the most 

important of which is near the center of the Willow 

Creek zone and is known both as the Middle Main 

bed and as the Willow Creek (No. 5) bed. The thickness and character of this bed have been proved by 

drilling and sampling for a distance of 4! miles alonq 

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

with the exception of two small areas of poor coal, 

the bed ~anges in thickness from 4 feet 3 inches to 

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

thick, generally occur 7 to 14 inches below the top 

of the bed. These partings can be removed by washing, 

but only with a resulting loss of some coal. The bed 

is over lain in the proved area by a 2 foot clay zone, 

which in turn is overlain by a thin coal, generally 

15 to 25 inches thick. 

On the eastern limb of the syncline the rocks have 

an average dip to the west of 28° to 33°. The regularity of dip, together with an absence of faults, 

makes this location a favorable one for mining. The 

rocks on the western limb, on the other hand, dip 

at least 45° and locally may be vertical or overturned. 

Although mining conditions would be difficult on the 

western limb of the syncline, the Middle Main bed in 

this area ranges between 3 feet 2 inches and 6 feet 

5 inches in thickness and has no partings. 

The coal in the Middle Main bed is of high-volatile 

A bituminous rank. An analysis on the as-received 

basis of a sample of coal from a drill hole at the northeast corner of sec. 12, T. 23 N. , R. 116 W. , sixth 

principal meridian, is as follows (Toenges and others, 

1945, pp. 44-45): 

Percent 

Moisture. -. . . • . . . . . . . . . . . . . . • . 2. 8 

Volatile matter. . . . . . . . . . . . . . . . 36. 9 

Fixed carbon .....•......• , . . . . 51. 4 

Ash.......................... 8. 9 

Sulfur........................ 0. 6 

B. t. u. ..•.•....••..••••••• 12, 780 

Coke manufactured from coal from this bed alone 

is unsuitable for use in the .blast furnace. With the 

addition of 50 to 60 percent of coal from the Sunnyside region, Utah, however, it will provide a coke 

nearly comparable to coke made from 100 percent 

Sunnyside coal. It is believed that the percentage 

of Sunnyside coal needed in the blend can be reduced 

by washing coal from the Middle Main bed to remove 

the impurities. Details of the physical and chemical 

properties of cokes, derived during tests of various 

blends of Willow Creek and other coals, are contained 

in the report by the Bureau of Mines (Toenges and 

others, 1945, pp. 14-25). 
In the area proved by drilling, which includes 

1, 710 acres, or nearly 3 square miles, the estimated 

original reserves of .,.coking coal in the Middle Main 

bed are 15,345,000 tons. Assuming minimum mining 

losses, the recoverable coal totals 11, 2i5, 000 tons 

(Toenqes and others, 1945, pp. 10-11}. Making generous 

additional allowances for losses incurred in eliminating th~ impurities-contained in the two clay partings, 

the recoverable clean marketable coal in the area 

proved by drilling totals at least 8, 000,000 tens 

(Andrews, 1944). 

South of the area of drilling, the coal in the 

Middle Main bed presumably has the same coking 

properties as the coal just described, and considerable 

mining of the bed has taken place. In the five townships where the Middle Main bed is 28 to 42 inches 

thick, the original measured reserves of coal under 

less than 2, 000 feet of overburden tota,l 37,940,000 

tons, and the original indicated reserves total 

58,700,000 tons. Additional measured reserves of 

8, 560,000 tons of coal and indicated reserves of 

39,420,000 tons of coal are present at depths between 

2, 000 and 3, 000 feet below the surface. 

Additional information about the co8.1 reserves of 

the Kemmerer-Willow Creek field and other fields 

in Wyoming is contained in reports by H. L. 

Berryhill and others (1950}. 

Rock Sprin s field, Sweetwater Count W omin 

(loc. . -- he coal in the Rock Springs field occurs 

in four main zones: the Rock Springs and Almond 

coal zones in the Mesaverde formation of Upper 

Cretaceous age; the Black Butte coal zone in the 

Laramie formation, also of Upper Cretaceous age; 

and the Black Rock coal zone in the Wasatch formation of Tertiary age. The Rock Springs zone near the base of the Mesaverde formation comprises the 

thickest and best coal in the field. The zone contains 

at least 12 coal beds that are individually from 2 to 

10 feet thick, and many other beds less than 2 feet 

thick. Partings of shale, bone, and sandstone occur 

in the coal beds. The thickness of each parting ranges, 

in general, from a fraction of an inch to 1 foot. 

The principal structure of the Rock Springs field 

is a low dome, in which the coal beds are exposed 

almost continuously around the non-coal-bearing 

central portion. Normal faults break the continuity 

of the beds on the flanks of the dome, and in areas 

where these faults are numerous, they may greatly 

increase the difficulty and expense of mining. Intrusions and extrusions are numerous in the northern 

half of the dome, but no alteration of the coal by 

igneous activity has been observed (Schultz, 1909, 

p~. 256-282;·1910, pp. 214-281). 

The coal of the Rock Springs zone is of highvolatile C bituminous rank, and the coal in the overlying zones is of subbituminous A, B, or Crank. 

An analysis on an as-received basis of a sample of 

coal from the Rock Springs No. 7 bed from the 

Superior A mine, three-quarters of a mile southeast 

of Superior, Sweetwater County, is as follows (U. S. 

Bur. Mines, 1931, pp. 74-75): 

10 

Percent 

Mqisture. . . . . . . . . . . . . . . . . . . . . . 12. 7 

Volatile matter ..........••. ·. . . 32. 8 

Fixed carbon. . . . . . . . . . . . . . . . . . 50. 0 

Ash.......................... 4. 5 

Sulfur .................... ·-· . . 0. 8 

Air -drying loss. . • . . . . . . . . . . • • 5. 6 

B. t. u. . . . . • . . . . . . . . . . . . . . . 11, 720 

Coal from some of the beds in the Rock Springs 

zone, particularly the No. 7, will yield a poor grade 

of coke that is unsuitable for metallurgical purposes. 

The estimated original reserves of the No. 7 bed, 

where it is at least 28 inches thick and has an overburden of no more than 2, 000 feet, total 899,440, OOC 

tons. Of this amount the measured reserves were 335, 160,000 tons, the indicated reserves 392,650,001 

tons, and the inferred reserves 171, 630, 000 tons. 

At depths between 2, 000 and 3, 000 feet below the 

surface the No. 7 bed contains additional indicated 

_ coal reserves of 35, 780,000 tons and inferred reserves 

of 205,710,000 tons. Approximately 107,580,000 

tons of coal from the No. 7 bed was mined or lost in 

mining-to January 1, 1950. All mining has taken place 

in parts of the bed included in measured original 

coal reserves. 

Cambria field, Westori County, Wyoming (loc. 8). -

The coal in the Cambria field is contained primarily 

in a single bed that occurs sporadically near the base 

of the Lakota sandstone of Lower Cretaceous age 

(Darton, 1904; 1905). Abrupt changes in compositior 

and thickness of the bed are common, but usually the 

bed ranges between 3 and 10 feet in thickness. Near 

the town of Cambria, where most of the mining has 

been carried on, the coal is typically 7 feet thick and 

of good quality. The structure of the Cambria field 

is a monocline in which the coal-bearing rocks dip 

gently to the southwest. 

The coal from this area is of high-volatile C 

bituminous rank, and an analysis on an 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, 1931, pp. 76-77): 

Percent 

Moisture. . . . . . . . . • . • . . . . . • . . . . . . . . . . . 10. 8 

Volatile matter . . . • . . • . . . . . . . . . . . . . . . . 39. 1 

Fixed carbon ............•...... ? • • • • • 35. 1 

Ash.................................. 15.0 

Sulfur............................... 4. 9 

Air -dryi.qg loss. . . . . . . . • . . . . . . . . . . . . . . 8. 1 

B. t. u .....•........................ . 10, 340 

Certain parts of this bed, presumably of greater 

purity than the remainder, have good coking qualities, 

and in the past were employed for. manufacturing cok@. 

to supply the Black Hills smelters and refineries. 

The Cambria field contained estimated original 

reserves of 21,920,000 tons of coal at least 28 inchef' 

/ thick covered by no more than 1, 000 feet of overburden. The coal that was measured or indicated 

by geologic evidence accounted for 18, 600, 000 tons 

of the total reserves, and an additional 3, 320,000 
tons was inferred to be present from qeneral qeoloqic 

knowledqe of the area. These reserves have been 

almost entirely mined or lost in mininq. Certainly 

the readily accessibie reserves of cokinq coal, which 

represented only a small percentaqe of the total reserves, are now depleted. 

Utah 

The Sunnyside-Castieqate field, Carbon County, 

is the only area in Utah that contains coal havinq the 

qualities necessary for the production of satisfactory 

metallurqical coke. The coal beds, which are of 

Upper Cretaceous aqe, crop out alonq the south side -

of the Uinta Basin. At the town of Sunnyside, where 

mininq has been carried on most extensively, the 

coal beds dip about 12° NE. Northwest and southeast of Sunnyside, however, the dip of the rocks 

decreases to between 2° and 4°. 

Two other coal-producinq areas, the Mount 

Pleasant field, Sanpete County, and the Kanab field, 

Iron County, have formerly been thouqht to contain 

deposits of possible cokinq coal. Tests on the coal 

from the Mount Pleasant field and experience in 

usinq the coal from the Kanab field, however, have 

shown that the coal from these areas does not possess 

the qualities required in the formation of qood blastfurnace coke. 

Sunn side-Castle ate field Carbon Count , Utah 

(loc. 9 . --The Sunnyside-Castleqate field is the most 

important source of cokinq coal in the West. In 1947, 

approximately one-third of the cokinq coal mined in 

this field was shipped to California, and two-thirds 

remained in Utah (De Carlo, Corqan, and Otero, 1947). 

As described by Clark (1928), the cokinq-coal area 

in the field comprises a strip about 40 miles lonq at 

the western end of the larqe Book Cliffs field of 

Colorado and Utah. The coal in the SunnysideCastleqate area has fair to qood cokinq qualities, and 

it has been mined extensively for this purpose at 

Sunnyside, Columbia, and Horse Canyon. 

The coal in the Sunnyside-Castieqate area occurs 

as a zone about 500 feet thick near the base of the 

Mesaverde qroup of Upper Cretaceous aqe. This formation consists of massive beds of sandstone, which 

crop out conspicuously in the Book Cliffs, and alternatinq beds of shale and coal, which lie between the 

sandstones. As many as nine coal beds are kn0wn to 

occur locally in the coal-bearinq zone, and it is 

believed that at least two are present throuqhout the 

area. 

The coal beds are qenerally lenticular in shape, 

and are, therefore, of varied thickness. 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 ranqes in thickness 

from 5 to 11 feet in the area of active mininq, but 

thins somewhat both to the northwest and to the south. 

Locally it is separated into two benches by a partinq 

of sandy shale 1 to 2 feet thick. Partinqs, however, 

are uncommon in this field, and the coal normally 

occurs as one bench. 

The Sunnyside-Castleqate coal field has a simple 

monoclinal structure. The beds dip 6° to 12° N. and 

NE. under the Book Cliffs, and, except for lit few 

11 

minor faults concentrated mostly at the south end of 

the field, are undisturbed. 

The coal in this field is of hiqh-volatile A and B 

bituminous ranks, and an analysis on the as-received 

basis of a sample of coal from the Lower Sunnyside 

bed at Sunnyside is as follows (Reynolds and others, 

194~, pp. 12-13): 

Moisture ........................... . 

Volatile matter .....•....•.....•..•.. 

Fixed carbon ......•..•.. ·· •.......... 

Ash ....•.......•........•....•..... 

Sulfur ............•...........•..... 

Air -dryinq loss .......•...•......... 

B. t. u. (moist, mineralPercent 

4.5 

38.5 

51.2 

5.8 

1.3 

2.2 

matter-f:ree) ..................... 14,020 

The Lower Sunnyside coal is a conspicuous 

example of a hiqh-volatile bituminous coal beinq 

used successfully in byproduct ovens for the production 

of satisfactory metallurqical coke. A typical analysis 

of coke produced from Lower Sunnyside coal from the 

Columbia mine shows the followinq physical and 

chemical properties (Reynolds, 1946, pp. 44-48): 

Apparent specific qravity............ 0. 78 

True specific qravity................ 1. 89 

B. t. u ..........•.•.•...•.•..•.••.. 12, 790 

Volatile matter ..................•. 

Fixed carbon ................•..... 

Ash .........•.•.......•.......•.. 

Sulfur ..............•..........•.. 

Cell space ....................••.. 

Percent 

1.7 

87.4 

10.9 

0.9 

58.7 

Tumbler and shatter tests: satisfactory for 

all purposes. 

Coke produced from Sunnyside coal yields only 

about two-thirds of its weiqht in furnace-size pieces, 

which contain many lateral and transverse fractures, 

but it is hard and holds up well in the blast furnace. 

At the town of Sunnyside more than 800 beehive 

ovens have been constructed, many of which were in 

use durinq World War II. Nearby at Columbia there 

are additional beehive ovens, but most of the coal is 

processed in a q10dern byproduct plant at Provo, Utah. 

Coke made from this coal is used in the Columbia 

Steel plant at Ironton, Utah, the Geneva Steel plant 

near Provo, Utah, the Fontana piant in southern 

California, and in local suqar refineries. 

The cokinq qualities of the coal in this field decrease northwestward from the Sunnyside area to 

Castleqate,and the coal at Castleqate is no lonqer 

used for cokinq purposes, thouqh pr-ior to 1903 it was 

the main source of supply for the State. Similarly, 

the coal in the Huntinqton Canyon area s~th of 

Castleqate has cokinq properties, but the ce~e made 

from this coal is inferior to that produced at-sunnyside. 

The total reserves of cokinq coal in the Lower 

Sunnyside bed are believed to be larqe enouqh to 

supply anticipated demands. Detailed calculations 
of the reserves in the Sunnyside-Castleqate field as 

measured along the outcrops and. indicated by the 

geologic continuity of the bed are tabulated by township and by individual bed in U. S. Geological Survey 

Bulletin 793 (Clark, 1928, pp. 101-102, 161). These 

figures show that the Lower Sunnyside bed contains 

estimated original reserves ranging from 5, 472,000 

to 8, 928,000 tons per square mile in a belt about 

10 miles long, and averaging about 2 miles wide, 

lying northwest of the town of Sunnyside. The coal 

here lies under less than 2, 000 feet of overburden. 

As commercial minin<J in the Lower Sunnyside bed is 

restricted for the most part to an area southeast of 

this belt, the entire tonnage in the belt, less normal 

expectable losses in mining, is available for future 

needs. Additional reserves are present in the Lower 

Sunnysidebedin the area of active mining, which ex- tends from a point about 1 mile northwest of Sunnyside, southeastward to a point several miles south 

of Horse Canyon. 

'-- Mount Pleasant field, Sanpete County, Utah 

{loc. 10). --The Mount Pleasant coal field, which is 

on the western side of the Wasatch Plateau, is 

favorably located with respect to the western steel 

industry, and for this reason it 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 diamond-drill 

hole was sunk by the U. S. Bureau of Mines to obtain 

samples for analysis (Toenges and Turnbull, 1943). 

The six coal beds encountered in the drilling are 

in the lower 200 feet of the Blackhawk formation of 

Upper Cretaceous age and range in thickness between 

18 inches and 5 feet 8 inches. On the western margin 

of the Wasatch Plateau, the rocks are broken by 

numerous faults, and west of the fault zone the coal 

beds have been dropped down to more than 2, 000 feet 

below the surface, thus placing them beyond the 

present practical limit 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 fie~d is as follows (Toenges and 

Turnbull, 1943, p. 14): 

Percent 

Moisture. . . . . . • • . • • . • . • . . • . . . . • • . 3. 2 

Volatile matter. . . . . . . . . . . . . . . . . . . 42. 9 

Fixed carbon. . . . . . • • . . . . • . . • . • . . . 45. 3 

Ash............................. 8. 6 

Sulfur........................... 0. 6 

Air -drying loss. . . . . . . • . • . • . . . . • . . 1. 4 

B. t. u ••..........•....•.....•• 12,890 

Coking tests made on six samples of this coal, 

which is of high-volatile A and B bitummous ranks, 

as is the coal from the Lower Sunnyside bed, revealed 

that the resulting coke was softer, considerably 

weaker, and more fingery than coke manufactured 

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. 

12 

Kanab field Iron County, Utah (loc. 11). --The 

Kanab field, wfiich has been described in U. S. 

Geological Survey Bulletin 316 (Lee, 1907, pp. 359-3"74)1 

is on the western edge of the Colob Plateau near 

Cedar City. The coal beds in this field crop out in 

the cliffs that border the Colob Plateau or in the 

canyons eroded in its margin. The coal occurs near 

the base of the Benton shale of Upper Cretaceous age 

in one minable bed 3 to 8 feet thick and in several 

additional thin beds. Partings of shale and clay 

between 1 and 4 inches thick split the coal into 

benches, -which individually are usually 2 to 3 feet 

thick. · 

The Kanab coal field is located along the northern 

extension of the Hurricane fault, and the conspicuous 

elevation of the cliffs above the basin to the west is 

due to displacement along the line of this fault. The 

coal-bearing rocks are somewhat folded and broken 

by minor faults, although locally they may be nearly 

horizontal. At places where the plateau is capped by 

basalt, the underlying sedimentary rocks are cut by 

large dikes, but no visible alteration of the coal by 

the igneous rocks has been reported. 

The coal of the Kanab field has a heat value ranging 

in general between 11,000 and 12,000 B. t. u. on a 

moist, mineral-matter-free basis. This is a borderline coal, therefore, and can be classified as either 

subbituminous A or high-volatile C bituminous in , 

rank, depending upon the weathering and agglomerating 

indices. 

An analysis on an as-received basis of a sample 

of coal from the Jones mine on Coal Creek, 7 miles 

southeast of Cedar City, Iron County, is as ~ollows 

(U. S. Bur. Mines, 1925, p. 37): 

Percent 

Moisture. . . . • • . . . . . . . • . . . . • • . . . . . . • . 10. 4 

Volatile matter. . . • • . • • . . • • . • . • • . . . . . 36. 3 

Fixed carbon........................ 43. 7 

Ash................................ 9. 6 

Sulfur.............................. 5. 8 

Air-drying loss..................... 1. 8 

B. t. u............................. 10,870 

The coke produced from this coal is high in sulfur 

and tends to be too friable for metallurgical use. 

Formerly, coke produced from coal obtained from 

the Kanab field near Cedar City was used to smelt 

the nearby Iron Springs iron ores. The results, 

however, were unsatisfactory, and the field, tkhich 

contains large reserves of coal, is generally not 

considered as a source of coking coal. 

Colorado 

Two of the important centers of western coking 

coal production --the Raton Mesa field and the 

Crested Butte field -- are in Colorado. In the Raton 

Mesa field, which extends from Huerfano County 

southward into New Mexico, the now extinct Spanish 

Peaks volcano has played an important part in the 

geologic history of the region. During the period 

of activity of this volcano, ·dikes and sills of igneous 

rock were intruded in radial arrangment into the 

surrounding coal-bearing sedimentary rocks, and 
f'le accompanying heat may have raised the rank of 

''le coal, and thus may havE improved the coking 

::)roperties. 

In the Crested Butte and adjacent fields of Delta, 

Gunnison, and Pitkin Counties, the geologic structure 

~ 8 very complex as a result of the uplift of the Rocky 

'l[ountains, and the coal-bearing rocks have been 

"r.,lded, faulted, and cut by large intrusions of igneous 

"')Ck. Consequently, the coal beds have been altered 

'1.Xtensively, and locally are suitable for coking 

Durposes. 

The Durango field, a third area in Colorado 

eontaining deposits of coking coal, is on the northern 

':'!dge of the San Juan Basin, which lies mostly in 

"~ew Mexico. In the vicinity of Durango, La Plata 

County, the coal beds dip to the south at angles 

'""anging .from 6° at places a few miles southwest of 

'"he town up to 40° at places a few miles to the north-

·~ast. In most of the San Juan Basin, the dips are 

"'ower and the coal is of lower rank than in the Durango 

~ield. The folding along the northern edge of the 

·~asin, therefore, appears to have caused significant 

alteration of the coal, and to be partly responsible 

.eor the localization of the deposits of coking coal. 

Crested Butte field and vicinity, Delta, Gunnison, 

.and Pitkin Counties, Colorado (loc. 12). --The 

Crested Butte coal field, together with several adjacent fields in Gunnison, Delta, and Pitkin Counties, 

constitutes the second largest coke-producing area 

in the West, exceeded only by the Sunnyside-Castlegate 

field in Utah. The general geology of the region is 

described in.two publications of the U. S. Geological 

Survey (Eldridge, 1894; Lee, 1912). In addition, an 

area containing coking coal in western Gunnison County 

near Somerset, known as the Coal Creek district, 

has been the subject of a recent cooperative investigation 

by the U. S. Geological Survey (Johnson, 1948) and 

the U. S. Bureau of Mines (Toenges and others, 

1947). 

The coal fields in the Crested Butte area are on 

the southeastern rim of the Uinta Basin, a large 

structural feature that extends into Utah. Igneous 

intrusions and the uplift associated with the formation 

of the Rocky Mountains have so disturbed the rocks in 

the Crested Butte area, however, 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 over lying Paonia shale member of the Mesaverde 

formation of Upper Cretaceous age. Several coal 

beds of minable thickness occur in each of the two 

members, and a total of eight beds have been observed 

in one locality. Correlation of the coal beds and 

accurate determinations of thickness are difficult 

because of the deformation in the area, but, in general, 

the thicker beds range between 4 and 12 feet in thickness. 

The Mesaverde formation is extensively folded, 

faulted, and cut by igneous rocks in the Crested Butte 

area. As a result of the defo~mation and the effect 

of 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 

13 

disappears where the coals have been altered. The 

variation in rank in this area 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. 

Coal with coking properties occurs at Gibson 

Ridge, Floresta, Mount Carbon, Red Gap, and 

Placita, in addition to the Coal Creek district, but 

because of the range in rank and quality of the coal 

in this area, the coke produced from the coal also 

shows a considerable range in quality. Gocd metallurgical coke is produced, however, from coal obtained 

at several places in Gunnison County. 

In the Coal Creek district, T. 13 S. , R. 89 W. , 

sixth principal meridian, the Mesaverde formation 

is divided from bottom to top in tv the Rollins 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. Recent 

exploration in the Coal Creek district has shown that 

the· lower coal member contains two principal beds. 

The lower bed, known as the Snowshoe, is between 9 

and 15 feet thick in the central part of the township, 

but thins to the north and· west and splits into two 

benches, ea.ch containing 1 to 7 feet of coal. The 

upper or Bear bed, although locally minable, is less 

than 3 feet thick throughout most of the Coal Creek 

district. The upper coal member of the Mesaverde formation includes one coal bed that within a limited area 

is 23 to 26 inches thick. In most of the Coal Creek 

district, however, the upper coal member contains 

only thin erratic coal beds ea.ch of which is usually 

less than 1 foot thick. 

Tests conducted by the Bureau of Mines show that 

coal from the lower bench of the Snowshoe bed and 

from the Bear bed yields a stronger coke than does 

coal from the Sunnyside bed in Utah. The coal from 

the upper bench of the Snowshoe bed produces a coke 

slightly inferior to coke made from Sunnyside coal. 

All three of the cokes are satisfactory in chemical 

composition, having sulfur contents between 0. 4 and 

0. 9 percent and ash contents between 6. 3 and 10. 9 

percent. The lower Snowshoe bed and the Bear bed, 

therefore, can be considered suitable for use in the 

production of metallurgical coke. 

In the area proved by drilling in T. 13 S., R. 89 W., 

the measured original reserves of coal total 

100,000,000 tons, of which 65,000,000 tons is of 

coking quality. Assuming a 70 to 80 percent recovery 

in mining, which in this area is believed to be attainable, 

recoverable reserves of coking coal in the drilled 

area are between 45,500,000 and 52,000,000 tons. 

None of this coal is immediately accessible from the 

outcrop, and it all lies under moderate to heavy overburden. At the confluence of Anthracite· and Coal 

Creeks, for example, the Bear bed was encountered 

in a drill hole at 658 feet, and the lower bench of the 

Snowshoe bed at 695 feet. East and northeast of this 

point the thickness of the overburden increases 

rapidly, and most of the coking coal lies from 1, 000 

to 2, 000 feet beneath the surface. 

In the entire area ofT. 13 S., R. 89 W., the 

original reserves of coal contained in the lower. coal 
member in beds at least 30 inches thick are estimated on. the basis of qeoloqic evidence to be 503, 000, 000 

tons, of which one-half to two-thirds can be considered as cokinq coal. Aqain, an allowance must be made 

for mininq losses. 

With the exception of the arc of iqneous rocks 

lyinq immediately sou~heast ofT. 13 S., R. 89 W., 

the areas to the northeast and south of the township are believed to contain coal havinq cokinq properties. 

Althouqh no reserve fiqures are available as yet for 

these additional areas of potential cokinq coal, their reserves should be comparable to those of the Coal 

Creek district. The reserves of cokinq coal in the 

entire Crested Butte area, therefore, are adequate 

to supply a larqe industrial demand. 

Norwood field Montrose and San Mi uel Counties 

Colorado loc. 1 . --Coke has been made locally from 

the coal in t e Dakota sandstone near Norwood in 

Montrose and San Miquel Counties, Colo. The coal 

beds are thin and discontinuous, however, and the 

cokinq coal frequently is limited to separate zones 

within the beds. In qeneral, the reqion is not considered as a source of coal for industrial coke. 

Duran o field La Plata Count Colorado 

(loc. 1 . -- he Duranqo field, whic lies on the 

northern side of the San Juan coal basin of Colorado 

and New Mexico, has been described by Taff (1907, 

pp. 321-337) and Zapp (1949). Coal in this field 

occurs in the Fruitland formation and in the Menefee 

formation of the Mesaverde qroup. The Fruitland 

f6rmation, which is the younqer, contains beds of 

coal of subbituminous rank that are not suitable for 

cokinq. The Menefee formation consists of interbedded sandstone and shale and has in its central 

part three, and in some places four, minable coal 

beds havinq cokinq properties. At least two of these 

beds have been extensively mined near .Duranqo. 

The minable coal beds in the Menefee formation 

ranqe in thickness between 2 and 7 feet, but partinqs 

of shale and bone, each several inches thick, qenerally 

divide the beds into benches each containinq 1 to 6 feet 

of coal. 

All the coal-bearing rocks dip to the south or 

southeast at angles ranging fro~ f!f or 8° near 

ijesperus, 8 miles west of Durango, to 40° in the area 6 miles northeast of Durango. A few faults are 

present in the field, but they are too small to interfere with mining operations. 

Most of the coal in the Menefee formation is of 

hiqh-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, pp. 88-89): 

Moisture .•.•.•.•••.•.••..•.... Volatile matter •.•...••..•••.•. 

Fixed carbon. •••.•....•.•••.•• Ash. •.....••••••.•..•.•.•.... · 

Sulfur .••..••.•••••••••••••••• 

Air-drying loss ..•....•...... ·. 

B. t. u. ••..•.......•...•....•. 

Percent 

5. 6 

36.2 

52.5 

5. 7 

0. 5 

2. 3 

13,120 

14 

Beehive ovens formerly were in operation at 

Durango and Porter, and the coke produced was used 

for smelting purposes. Recent tests by the Bureau 

of Mines of the aqqlutinatinq, swelling, and plastic 

properties of 19 samples of coal from this area 

indicated that most of the samples had qood cokinq 

qualities, and that many were suitable for use in by· 

product ovens (Fieldner and others, 1945, p. 58). 

Although there are local variations in the cokinq . 

quality of the coal in the Duranqo area, some of the 

coal in the Menefee formation probably could be treate1 

by modern cleaning and processinq methods and used 

to manufacture metallurqical coke. · 

The oriqinal measured reserves of thicker 

accessible coal in the Duranqo field, as estimated by 

· Zapp, total ~7, 180, 000 tons. All of this coal is in 

beds more than 42 inches thick at depths of less than 

1, 000 feet below the surface. Takinq into consideraticn 

the coal that has been mined or lost in mining, the 

remaininq measured reserves as of January 1, 1949, 

are 64,300,000 tons, of which 41,790,000 tons can be 

classified as recoverable reserves assuming 

65-perqent recovery of the coal. Larqer indicated 

and inferred reserves of coal also are present in the 

field at depths between 1, 000 and 3, 000 feet below 

the surface (Zapp, 1949). 

Raton Mesa field, Huerfano and Las Animas 

Counties Colorado and Colfax Count New Mexico 

loc. 1 . -- e Raton Mesa 1eld, whic inclu es an 

area of about 2, 000 square miles in Huerfano and 

Las Animas Counties, Colorado and Colfax County, 

New Mexico, is the third larqest producer of coking 

coal in the West. Detailed descriptions of different 

parts of the field are contained in several publications 

of the U. S. Geoloqical Survey (Hills, 1899, 1900, 

1901; Lee and Knowlton, 1917; Lee, 1922), and the coal 

has been the subject of much technologic work by the U.S 

Bureau of Mines (Reynolds and others, 1946, pp. 75-71~; 

Fieldner and others, 1945, pp. 58-59; Parry, 1943, 

p. 32). 

The coal in this field occurs in three zones, the 

lower in the Vermejo formation of Upoer Cretaceous 

age, and the middle and upper in the Raton formation 

of Cretaceous and Paleocene ages. In parts of the 

field as many as eight workable beds can be found, 

and at least one or two are present in all localities. 

The beds are generally discontinuous, however, and 

only a few are persistent over wide areas. 

The beds in the lower zone are most persistent, 

and between one-and eight beds,· ~dividually containing 

2 to 14 feet of coal, are workable. Mining operations 

are extensive in this zone, which generally contains 

the highest grade bitumino~ coal in the field. In the 

middle Z<>ne, the workable.beds, each of which averaqe:o:; 

4 feet in thickness, are known only in Las Animas 

·County, Colorado. In the upper zone, the beds thicken 

and thin within short distances, but those that are workable are between 2 and 6 feet thick. 

Structurally, the Raton Mesa field. is~ northward 

trending syncline with steep dips on the west side and 

relatively gently dips on the east. In the northwestern 

part of the syncline lies the extinct Spanish Peaks 

volcano with numerous radiatinq dikes and sills of 
of igneous rock that have produced many local 

variations in the character of the coal and impose 

problems of mining in the vicinity. 

Only by the examination of a large number of 

analyses can the range in rank of .the coal in the Raton 

Mesa field be determined (U. S. Bur. Mines,1936, 

pp. 44-51; 1937, pp. 76-84, 92-101). Where the coal 

is suitable for coking purposes, as at Trinidad, it is 

mined extensively to supply the byproduct ovens at 

Pueblo, Colo. The coal used to manufacture coke is 

generally washed to remove some of the impurities 

and blended with a small amount of noncoking coal 

or the char obtained by devolatilizing available lowrank coal. The resulting coke is much superior to 

any other commercial metallurgical coke produced 

from western coal. Where the coal is not suitable 

for coking, as at Walsenburg, it is mined for railroad and domestic use. 

The reserves of coking coal in the Raton Mesa 

field have not yet been determined accurately because of the lack of adequate information concerning 

local variations in the quality of the coal and because 

of the discontinuity of the coal beds. The total 

estimated original reserves of coal of all classes in 

the field are quite large, however, and the reserves 

of coal of coking quality are believed to represent a 

considerable part of the total. 

In 1949 and 1950 the U. S. Geological Survey was 

engaged in a detailed study of a part of the Raton Mesa 

field covering about 70 square miles between the 

towns of Stonewall, Tercio, and Weston fu Las Animas 

County, Color~do, near Trinidad. The first report 

by Wood and others (1951) on the results of this work 

shows that the original reserves of coal in the area 

total 490, 969, 000 tons. The Raton formation contains 

262,486,000 tons of coal, of which 151,266,000 tons 

is classed as measured and indicated reserves and 

111,220,000 tons as inferred reserves. The Vermejo 

formation contains 228,483,000 tons of coal, of which 

72,340,000 tons is classed as measured and indicated 

reserves and 156,143,000 tons as inferred reserves. 

Most of the measured, indicated, and inferred reserves 

of coal in the Stonewall-Tercio area lie under less 

than 1, 000 feet of overburden. 

A recent study of the coal reserves of New Mexico 

by Read and others (1950) indicates that in Colfax 

County the estimated original reserves of measured 

and indicated bituminous coal in beds 28 inches or 

more in thickness, under less than 2, 000 feet of 

overburden, total 1, 486, 900,000 tons. An additional 

1, 445, 200, 000 tons of bituminous coal 28 or more 

inches in thickness is inferred to be present at depths 

of less than 2, 000 feet below the surface, and 

376, 900, 000 tons of bituminous coal at least 42 inches 

thick is inferred to be present at depths between 

2, 000 feet and 3, 000 feet below the surface. As 

much of the coal in the Raton Mesa field is of coking 

quality, these figures give some indication of the 

probable reserves of coking coal in the part of the 

field that lies in Colfax County, New Mexico. 

·New Mexico 

The most important coking coal area in New 

Mexico, the Raton Mesa field, lies partly in Colorado, 

and has already been describ_ed with the Colorado fields. 

15 

The Monero field, Rio Arriba County, which lies 

southeast of Durango, is on the northeastern side of. 

the San Juan Basin, and some of the coaJ beds, as at 

Durango, have coking properties, . ln the Cerrillos 

field, Santa Fe County, where the coal-bearinq rocks 

have been intruded and upturned by igneous rocks, 

some coal has coking properties, but,tlre reserves 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, and the coking 

properties of the coal are due in part to alteration 

accompanying the close folding and faulting of the 

sedimentary rocks. 

Monero field, Rio Arriba Count New Mexico 

(loc. 1 . --The Monero coal field has been described 

in a brief r~port by Gardner (1909, pp. 352-363), 

and the stratigraphy and structure of the area have 

been mapped more recently by Dane (1948). The coal 

field lies on the northeast side of the San Juan coal 

basin, immediately south of the Colorado line. The 

coal having coking properties occurs in the Gibson 

coal member of the Mesaverde formation as three 

minable beds which vary individually from 3 feet 

7 inches to 4 feet in thickness. Partings of sandstone 

and shale from 7 to 9 inches thick split the beds into 

benches of coal that range in thickness between 

1 foot 4 inches and 3 feet 4· inches. 

In the vicinity of Monero and Lumberton, where 

most of the mining in this area is 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 the 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, pp. 56-57): 

Percent 

Moisture. . . . .. . . . . . • . . . . . . • . . . . . . . • . . 2. 4 

Volatile matter. . . . . • . . • . . . . • . . . . . . . . 38. 0 

Fixed carbon. . . . . . . • . . . . . . . . . . . . • . • . 52. 3 

Ash................................ 7. S 

Sulfur.............................. 1. 5 

Air-drying loss..................... 1. 2 

B. t. u. .........•...............•.. 13,600 

According to Read and others (1950), the original 

reserves of measured and indicated bituminous coal 

in Rio Arriba County in beds 28 uiches or more in 

thickness, under less than 2, 000 feet of overburden, 

total 4, 500, 000 tons. An additional 390,300,000 tons 

of bituminous coal 14 inches or more in thickness may 

be inferred to be present under overburdens of less 

than 3, 000 feet. All of the coal mined in the Monero 

field is at present used for railroads and domestic 

purposes. Certain beds, however, are known to 

possess coking qualities in parts of the field,· although 

the reserves of such coal have not been determined. 

Cerrillos field Santa Fe Count New Mexico 

(loc. 1 . --The Cerrillos field, whic is one o t e 

oldest coal-producing areas in the West, lies 25 miles 

south of Santa Fe, near the town of Madrid on the main 

_line of the Atchinson, Topeka, and Santa Fe Railroad. 
As described in a report by Lee (1913, pp. 285-312), 

the coal in the Cerrillos field is in the Mesaverde 

formation of Upper Cretaceous age, which consists 

of a massive basal sandstone overlain by a sequence 

of interbedded coal-bearing sandstones and shales. 

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 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. 

Dikes and sills of igneous rock cut 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. During 1942-1943 the U. S. 

Geological Survey and the U. S. Bureau of Mines 

.jointly examined areas in the field 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 

reserves of coking coal were too small to warrant 

further exploration (Toenges, Turnbull, and Mould, 

1943}. 

Cartha e field Socorro Count New Mexico 

(loc. 18. --The Carthage field, Socorro County, 

New Mexico is about 12 miles southeast of San Antonio. 

As described by Gardner (1910, pp. 452-460), the 

minable coal in the field occurs as a single bed that 

averages about 5 feet in thickness and lies just above 

the basal sandstone of the Mesaverde formation of 

Upper Cretaceous age. Partings of clay, shale, and 

bone that range in thickness from 2 to 15 inches split 

the coal so that the principal bench is between 2 and 

4 feet thick. Several other coal beds are present in 

the Mesaverde formation above the minable bed. 

The Carthage field is located on an uplifted fault 

block, which in turn has been broken by a system of 

north-south normal faults. Because of the faulting 

and numerous change$ in dip, the complexity of the 

structure is such that mining operations can seldom 

follow the coal from one minor block to another. 

The coal in the Carthage field is of high-volatile 

A bituminous rank. An analysis on an as-received 

basis of a sample of coal from the Government mine 

at Carthage is as follows (U. S. Bur. Mines, 1936, 

pp. 62-63): 

Percent 

Moisture. . . . . . . . . . . . . . . • . • . . . . . 3. 7 

Volatile matter. . . . . . . . . . . . . • . . • 39. 7 

Fixed carbon................... 46. 7 

Ash ............•............ ·.. 9. 9 

Sulfur......................... 1. 0 

Air-drying loss................ 2. 2 

B. t. u ..•.....•....•.........•. 12,860 

16 

The field has been mined more or less continuously 

since 1861, and prior to 1894 beehive coke ovens were 

operated. In 1942, the field was examined by the U. S. 

Geological Survey and the U. S. Bureau of Mines as 

a possible source of coking coal (Reynolds and others, 

1946, pp. 10, 25, 35, 37-38,· 41, 48, 62, 64, 67-68, 

76). Tests showed that the coal yielded a fair coke 

inferior in quality to that produced at Sunnyside, Utah. 

Most of the Carthage field has been worked out, and 

the known areal extent of the coal bed at minable depth · 

is no more than 2 square miles. 

Oklahoma-Arkansas 

The coal fields in southern Oklahoma and Arkansas 

together form a continuous area of coal-bearing rocks 

of Pennsylvanian age that crop out as a series of 

generally eastward trending anticlines and synclines 

cut by thrust faults having approximately the same 

strike as the folds. As a result of the folding and 

faulting , the coal has been somewhat altered and 

shows a marked increase 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 western Arkansas, where the deformation was 

greater, the coal is of low-volatile bituminous rank. 

Some 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. 

Henr etta district Okmul ee Count Oklahoma 

(loc. 1 . --The Henryetta district in Okmulgee County, 

although only 10 square miles in size, is one of the 

most extensively mined areas in the Oklahoma coal 

field. Coal is produced from one bed, the Henryetta, 

in the Senora formation of Pennsylvanian age. Usually 

this bed is 34 to 36 inches thick and contains clean 

coal, but locally 2 to 4 inches of impure or bony coal 

may form a parting in the center of the bed. The 

coal-beai-ing 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 co~l 

bed is only a minor disadvantage. Exploratory 

drilling west of the mined area shows that the coal 

thickens in that direction to 39 inches and lies 580 to 

630 feet below the surface. 

Generally the coal in the Henryetta bed is of 

high-volatile B bituminous rank. An analysis on an 

as-received basi~ of a sample of coal from this bed 

from the Whitehead No. 2 mine at Henryetta is as 

follows (U. S. Bur. Mines, 1928,, Tech. Paper 41t; 

p. 21): 

Percent 

Moisture. . . . . . . . . . . . . . . . . . . . . . . . . . . 7. 6 

Volatile matter. . . . . . . . . . . . . . . . . . . . . 34. 7 

Fixed carbon. . . . . . . . . . . . . . . . . . . . . . . 52. 7 

Ash............................... 5. 0 

Sulfur............................. 0. 7 

Air-drying loss.................... 3. 8 

B. t. u. ~ ••....•.•.•••••....•...•.•• 12, 880 

The U. S. Bureau of Mines in cooperation with 

the Oklahoma Geological Survey conducted eJ;Cperiments 

in 1941 to determine the coking properties of Henryetta 

coal both when used alone and when blended with 

Lower Hartshorne coal Jrom Sebastian County, ArkansG'.S. 
Two analyses on a dry basis of the cokes that were 

produced are as follows (Davis and Reynolds, 1941): 

100% Henryetta coal 80% Henryetta coal 

Percent. 

Vo.latile matter •• 10. 5 

Fixed carbon ••. 82.4 

Ash........... 7. 1 

Sulfur......... 1. 6 

B. t •. u. • • . • • • • 13, 800 

20% Hartshorne coal 

Percent 

• • • • • . . • . • . • 1. 8 ••.••••••.•• 89.7 

•••••••••••• 8. 5 

• • • • • • • • • • • • 1. 8 

•••••••.•. 13,230 

Henryetta coal does not form a coke as stroncJ 

as that obtained from the eastern coal. customarily 

used, but it is believed to be suitable for making 

blast-furnace coke. Blending with 20 percent lowvolatile Hartshorne coal, however, produces a coke 

with greatly improved strength. The low softening 

temperature of the ash makes the coke unsuitable 

for use in a water -gas generator and probably for 

domestic heating because of clinkering, but this is 

no disadvantage in the. blast furnace. 

No estimates of the coal reserves of the Henryetta 

field are available, but according to a report of the 

Oklahoma Geological Survey in 1941, drilling has 

shown that beyond the area of active mining there ~e 

additional coal reserves that can be developed (Davis 

and Reynolds, 1941, p. 2). 

The southern ~t of the Oklahoma coal field, 

coal, 15lttSbilrg, I toka, Latimer, and Le Flore 

Counties Uoc. 20). --Coal of coking quality is present 

is the southern part of the Oklahoma field in an eastwest belt extending through Coal, Pittsburg, Atoka, 

Latimer, Haskell,and Le Flore Counties (Thorn and 

Rose, 1935; Hendricks and, others, 1939; Oakes and 

Knechtel, 1948; Knechtel, 1949). The coal-bearing 

rocks in the southern Oklahoma field are of Pennsylvanian age and locally contain at least seven workable 

coal beds, of which the most important are the Upper 

and Lower Hartshorne and the McAlester. Numerous 

other beds are present, but eaeh is usually less than 

12 inches thick. 

The Lower Hartshor~e coal bed lies near the 

central part of the Hartshorne sandstone, which 

includes interbedded shale and has a total thickness 

of 50 to 500 feet. The coal bed ranges from 2! to 

6 feet in thickness, averaging 4 feet in thickness 

where mined. Partings may be absent entirely in 

some places but as many as four are found locally. 

,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 bed is located near 

the base of the McAlester shale, which is 1, 200 

to 2, 800 feet thick and composed predominantly of 

dark shale. The thickness of the coal is between 

1 foot 8 inches and 5 feet 7 inches and averages· about 

3 feet. Usually the bed contains no partings, but from 

one to three, each a fraction of an inch thick, may be 

present locally. 

The McAlester coal bed occurs just above the 

middle of the McAlester shale: It ranges from 

1 foot 8 inches to 4 feet in thiclmess, and, where 

mined, it averages 3! feet. Prospecting has shown, 

however, that the McAlester bed thins to less than 

17 

2! feet throughout much of its area of occurrence. 

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. 

The structure of the southern Oklahoma coal field 

consists principally of a series of eastward or northeastward trending folds. The synclines are broad and 

flat, but the anticlines are tightly folded, and the dip 

of the rocks, which varies from 5° to 90°, has to a 

great extent determined the areas where mining has 

taken plac~. Where the dips are less than 20°, mining 

operations have been extensive, but the more steeply 

dipping coal beds have been ww-ked only locally. 

Thrust faults having displacements that vary from 

a few feet to more than 1, 000 feet also trend generally 

eastward or northeastward across the coal field and 

often can be traced for several miles. In addition, 

small normal faults are present in the area. 

The coal in the southern Oklahoma field ranges 

from high-volatile C to low-volatile bituminous in 

rank. The difference in rank within the various parts 

of a single bed is often greater than the difference in 

rank of two separate beds, and the character of the 

coal can be shown only by many analyses (U. S. Bur. 

Mines, 1928, Tech. Paper. 411, pp. 13-29). In 

general, the rank of the coal increases in an eastward 

direction. The coal is of high-volatile bituminous 

rank in the western part of the field and grades 

eastward into coal that is characteristically of lowvolatile bituminous rank. 

Between 1880 and 1908, coke was manufactured 

in the McAlester district, in the western part of the 

southern Oklahoma field, from high-volatile McAlester 

and Hartshorne coal. Only washed slack coal, however, 

could be used satisfactorily. An analysis of the coke 

that was produced from washed coal was as follows 

(Hendricks and others, 1939, pt. 1, p. 81): 

Volatile matter ......•..•......... 

Carbon ......................... . 

Ash ............................ . 

Phosphorus ..................... . 

Sulfur .......................... . 

Percent 

2.590 

85.330 

ll. 120 

0.043 

1. 750 

Also, 40 ovens were used at Howe in the 

eastern part o{ the field from 1900 to 1905 for 

the production of coke from low-volatile Lower 

Hartshorne coal. 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. 

Recently, coking experiments were conducted 

by the U. S. Bureau of M4tes ill cooperation 

with the Oklahoma Geological .Survey on samples 

of McAlester coal from Pittsburg County and 

Lower Hartshorne coal from Le · flore County, 

Oklahoma (Davis and Reynolds, 1942). Analyses on a dry basis of the cokes that were produced 

are as follows: 
70% McAlester coal 

100% McAlester coal 30% Hartshorne coal 

Apparent specific 

gravity.............. . 71 

True specific 

gravity. . . • • . • • . • . . . . 1. 46 

B. t. u. • •...••••... 13, 940 

Percent 

Volatile matter......... 12. 0 

Fixed carbon........... 81.8 

Ash................... 6. 2 

Sulfur ••....••........• • . 5 

• 82 

• . . . • • . . . . 1. 93 

••.•... 13, 440 

Percent 

.. 0........ 1. 8 

91. 1 

7. 1 

.8 

The high-volatile McAlester coal alone yields a 

very weak coke, but blending with 20 percent lowvolatile Lower Hartshorne coal produces 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 within the limits set for blast-furnace 

coke. The low softening temperature of the ash from 

both coals prohibits the use of the coke in water -gas 

sets and in domestic heating, but will not affect its 

performance in a blast furnace. 

With the recent expansion of the steel industry in 

the West, Oklahoma has again become a producer of 

coking coal. Since 1944, low-volatile coal from 

eastern Oklahoma has been used-principally in the 

coke ovens at Provo, Utah, Fontana, Calif., and 

Daingerfield, Texas-for blending with high-volatile 

coals to improve the physical properties of the 

metallurgical <;oke produced in the western states. 

The reserves of low-volatile coal in eastern 

Oklahoma appear to be of the order of 2, 000,000,000 

tons, as determined by recent geologic mapping 

(Oakes and Knechtel, 1948; Knechtel, 1949). The 

total coal reserves of the Oklahoma field have not 

as yet been accurately calculated, but the reserves 

of coking coal appear to be adequate to maintain the 

present increased rate of production. In addition to 

the three principal coal beds in the field, at least 

four other beds, although somewhat thinner, are of 

minable thickness and can be developed as the Upper 

and Lower Hartshorne and McAlester beds are exhausted. It is believed that the coal from all of these 

seven beds can be used for coking or for coking blends. 

Western Arkansas field, Sebastian, Crawford, 

Franklin Lo an Scott Johnson, Po e and Yell 

Counties loc. 21 . --The western Arkansas field, 

which has been described in two reports of the U. S. 

Geological Survey (Collier, 1907; Hendricks and Parks, 

1937), is an eastward extension of the Oklahoma field. 

In general, the same formations are present, although 

few of the coal beds can be correlated from one state 

to the other. The coal-bearing formations in Arkansas 

are the Hartshorne sandstone, the McAlester shale, 

and the Savanna sandstone. Each of these formations 

is equivalent to the formation of the same name in 

Oklahoma, except that · the upper part of the 

Hartshorne sandstone between the Lower and 

Upper Hartshorne coal beds is absent throughout 

most of the Arkansas field. The contact between 

the Hartshorne sandstone and the overlying 

McAlester shale, therefore, is placed below the 

Lower Hartshorne coal bed in Arkansas, rather 

than at the base of the Upper Hartshorne coal 

bed, as in Oklahoma. 

18 

Three coal beds - the Lower Hartshorne, the 

Charleston, and the Paris -are of commercial 

importance in the Arkansas field, and numerous 

other beds, each less than 18 inches thick, are 

present. The Lower Hartshorne bed, which lies in 

the basal part of the McAlester shale, is generally 

correlated with the Lower Hartshorne bed in Oklahoma. 

Normally this bed is between 2 and 7 feet thick and 

is the most important coal in Arkansas. Partings 

are sometimes lacking but when they do occur, most 

of them are between 1 and 6 inches thick. Locally 

the indiviqual partings increase to as much as 3 

feet thick, and in such places only th~ upper bench of 

coal is mined. 

Locally a coal bed correlated with the Upper 

Hartshorne of Oklahoma lies 40 to 90 feet above the 

Lower Hartshorne bed, but it is a thin, bony coal 

and has little or no commercial value. 

The Savanna sandstone, over lying 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, 

generally has a thickness of 14 to 20 inches, and the 

upper bed, the Paris, has a thickness of 18 inches, 

increasing locally to 34 inches. 

The Arkansas coal field extends east-west and 

lies between the Ouachita Mountains on the south and 

the Boston Mountains on the north. Different types 

of earth movements formed the two mountain areas, 

and the structure in different parts of the coal field 

varies according to position with respect to these two 

relatively uplifted areas. In the Ouachita Mountains 

horizontal pressures formed thrust faults and tight 

folds having limbs that are steeply dipping or overturned. On the south side of the Arkansas coal field, 

therefore, the rocks are folded and locally thrustfaulted, though not so intensely as in the Ouachlla 

Mountains. In the Boston Mountains the rocks dip 

only slightly southward and are broken by high-angle 

normal faults. The northern side of the coal field 

has the same type of structure, although the degree of 

folding and amount of faulting are somewhat greater 

than in the Boston Mountains due to the additional 

pressure from the south. 

All the coal in the western part of the Arkansas 

field is of low-volatile bituminous rank, but toward 

the eastern part of the field the coal increases in 

rank to semiant:t:tracite. An analysis on the asreceived basis of a sample of low-volatile coal from 

the Central No. 10 mine at Hartford, Sebastian 

County, is as follows (U. S. Bur: Mines, 1928, Tech. 

Paper 416, pp. 12-13): 

Percent 

Moisture. . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 4 

Volatile matter. . . . • . . . . . . . . . . . . . . . . 19. 4 

Fixed carbon. . . . . . . . . . . . . . . . . . . . . . . 66. 3 

Ash............................... 10.9 

Sulfur............................. 1. 1 

Air -drying loss. . . . . . . . . . . . . . . . . . . . 2. 8 

B. t. u. .................. • ......... 13, 140 

Low-volatile coal from the Arkansas field, when 

blended with high-volatile coal produces a coke with 

improved physical properties, particularly increased 

strength. Since 1944, therefore, this coal has been 

shipped to California, Utah, and Colorado for use in 

blends with western high-volatile coals. 
The total original reserves of bituminous coal in the 

Arkansas field are inferred to be 1, 396,000,000 tons, 

of which 82,785,000 tons of coal was produced through 

1949. Assuming a loss in mining of 50 percent of the 

coal in the ground, a total of 165,570,000 tons of coal 

was min~d or lost in mining through 1949. The remaining inferred reserves as of January, 1950, therefore, totaled 1, 230,430,000 tons. As most of the bituminous coal in the Arkansas field is suitable for coking 

or for use in blends, this figure closely represents 

· the remaining inferred reserves of coking coal. 

CONCLUSION 

Although the 21localities in the West described 

above collectively contain large reserves of coal that 

has coking properties, only a few contain adequate 

reserves of the better quality coals necessary for the 

i production of metallurgical coke. The Sunnyside-

: Castlegate field, Utah; the Raton Mesa field, ColoradoNew Mexico; the Crested Butte field, Colorado; and 

1 the southeast Oklahoma and Arkansas fields, contain 

, most of the reserves of the better quality coals, and 

I account for most of the western production of coking 

coal. Several other fields, notably the WilkesonCarbonado-Fairfax, and Roslyn fields, Washington; 

I and the Kemmerer-Willow Creek field, Wyoming, 

1 contain adequate reserves of coal that by washing 

: and blending can be made to yield coke approaching 

in quality that made from coal obtained in the main 

I producing fields listed above. The remaining fields, 

for the most part, either yield coal that is only feebly 

: coking or contain only small reserves. 

The practice of washing and blending coal to improve 

~ the quality of the resulting coke is employed at most 

coke-producing centers in the West. Materials typically 1 added to th~ western coals to improve the quality of 

I the blends include low-volatile bituminous coal, petro.-

' leum 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 reserves of suitable 

. low-volatile bituminous coal, and the most convenient 

assured supply is from the southeastern Oklahoma and 

Arkansas fields, where there are large reserves of 

coal of this rank. Coke produced from blends of western coals does not equal the best eastern cokes in 

quality, but with a growing market for industrial 

products in the West, blends utilizing the better 

I 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 reserves of western 

coking coal for use in iron and steel manufacturing 

is largely dependent, therefore, upon technological 

advances in washing and blending procedures, and in 

the design and operation of blast fUfnaces to utilize 

the available product effectively. 

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---------------, Knechtel, M. M., Dane, C. H., 

Rothrock, H. E., and Williams, J. S., 1939, 

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~--------, 1900, U. S. Geol. Survey Geol. Atlas, 

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---------, 1901, U. S. Geol. Survey Geol. Atlas, 

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Johnson, V. H., 1948, Paonia coal field, Delta and 

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Lee, W. T. , 1907, The Iron County coal field, Utah: 

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---------, 1912, Coal fields of Grand Mesa and the 

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---------, 1913, The Cerrillos coal field, Santa Fe 

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---------, 1922, U. S. Geol. Survey Geol. Atlas, 

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---------, and Knowlton, F. H., 1917, Geology and 

paleontology of the Raton Mesa and other regions in 

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Oakes, M. C., and Knechtel, M. M., 1948, Geology 

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properties of western coals: U. S. Bur. Mines Tech. 

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Rose, H. J., 1927, Selection of coals for the manufacture of coke: Am. Inst. Min. Met. Eng., Trans. , 

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Saunders, E. J., 1914, The coal fields of Kittitas 

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Schultz, A. R., 1909, The northern part of the Rock 

Springs coal field, Sweetwater County, Wyo. : U. S. 

Geol. Survey Bull. 341-B, pp. 256-282. 

------------, 1910, The southern part of the Rock · Springs coal field, Sweetwater County, Wyo. : U. S. 

Geol. Survey Bull. 381-B, pp. 214-281. 

------------, 1914, Geology and geography of a portion of Lincoln County, Wyo. : U. S. Geol. 

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Taff, J. A., 1907, The Durango coal district, Colorado; 

· ·U. S. Geol. Survey Bull. 316-E, pp. 321-337. 

Thorn, w. T., and Rose, Pat, 1935, Stigler-Poteau 

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U. S. Geol. Survey Prelim. Map. 

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-------------, and Turnbull, L. A., 1943, Bed 

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six beds at the Mount Pleasant project, S~npete 

County, Utah: U. S. Bur. Mines War Mine~als 

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---------, and others, 1945, Reserves, bed 

characteristics, and coking properties· of the 

Willow Creek coal bed, Kemmerer district, 

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Paper 673. 

---------, and others, 1947, Investigation of coal 

deposits in the Coal Creek district, Gunnison 

County, Colo.: U. S. Bur. Mines Rept. Inv. 4104. 

U. S. Bur. Mines, 1925, Analyses of Utah coals: 

U. S. Bur. Mines Tech. Paper 345. 

----·---, 1928, Analyses of Oklahoma coals: U. S. 

Bur. Mines Tech. Paper 411. 

--------, 1928, Analyses of Arkansas coals: U. S. 

Bur. Mines Tech. Paper 416. 

-------, 1931, Analyses of Wyoming coals: U. S. 

Bur. Mines Tech. Paper 484. 

---------, 1932, Analyses of Montana coals: U. S. 

Bur. Mines Tech. Paper 529. 

---------, 1936, Analyses of New Mexico coals: 

U. S. Bur. Mines Tech. Paper 569. 

---------, 1937, Analyses of Colorado coals: U. S. 

Bur. Mines Tech. Paper 574. 

---------, 1941, Analyses of Washington coals: U. S. 

Bur. Mines Tech. Paper 618 (Supplement to Tech. 

Paper 491). 

Utah Conservation and Research Foundation, Lowtemperature Carbonization of Utah coals: Utah 

Conservation and Research Foundation, Report to 

the Governor and Legislature, May, 1939. 

Warren, W. G. , Norbisrath, H.-, Grivetti, R. M .• 

and Brown, S. P. , 1945, Coal fields of King County, 

Wash. : U. S. Geol. Survey Prelim. Coal Map. 

Wood, G. H., Johnson, R. B., Eargle, D. H., 

Duffner, R. T., and Major, Harold, 1951, Geology 

and coal resources of the Stonewall-Tercio area, 

Las Animas County, Colo.: U. S. Geol. Survey 

Coal Inv. Map C-4. 

Yancey, H. F., and others, 1943, Byproduct cokeoven tests of Washington coals: U. S. Bur. Mines 

Rept. Inv. 3717. 

Zapp, A. D., 1949, Geology and·coal resources of 

the Duranqo area, La Plata and Montezuma Counties, 

Colo. : U. S. Geol. Survey Oil and Gas Inv. Prelim. 

Map 109.