GEOLOGICAL SURVEY CIRCULAR 343

MICROSCOPIC STUDIES OF 

URANIFEROUS COAL DEPOSITS

This report concerns work done on 

behalf of the U. S. Atomic Energy 

Commission and is published with 

the permission of the Commission.

UNITED STATES DEPARTMENT OF THE INTERIOR 

Douglas McKay, Secretary

GEOLOGICAL SURVEY 

W. E. Wrather, Director

GEOLOGICAL SURVEY CIRCULAR 343

MICROSCOPIC STUDIES OF URANIFEROUS COAL DEPOSITS

By James M. Schopf and Ralph J. Gray

This report concerns work done on 

behalf of the U. S. Atomic Energy 

Commission and is published with 

the permission of the Commission.

Washington, D. C., 1954

Free on application to the Geological Survey, Washington 25, D. C.
COMPOSITION,IN PERCENT

Total anthroxylon

URANIUM 

Ash profil

(air-dry ba

31740ft

95 percent of coal thickness studied in thin section

p/m/g-pulses per minute per gram

+ -coal layer sample of relatively low uranium content 

* -caol layer sample af relatively high uranium content

Total anthraxylon

Total composition, in percent, for layers between 317.40ft and 32

Pre-vitrain (woody) 33.5 

Attrital anthraxylon 14.8 

Translocent attritus 31.0

//////////////////////////m

Opaque 

attritus

Opaque attritus 7

Fusain I

Visible impurities 2

Ash pro

(air-dry 

Fusain

*TE-24

322.56ft gg perCent af coal thickness studied in thin section

! f

Total composition,in percent, for layers between 321.37ft and 322.56ft

Pre-vitrain (woady) 56.0 Opaque attritus 0.5

Attrital anthraxylon 6.8 Fusain 0.8

Scale for co

0 2

I I I !..J_

Translucent attritus 19.0 Visible impurities 17.0

Figure 1. Composition of lignite in upper bench, Olesrud bed, drill hole SD-10, Slim Buttes area, Hardin
MICROSCOPIC STUDIES OF URANIFEROUS COAL DEPOSITS

By James M. Schopf and Ralph J. Gray

CONTENTS

Page

Abstract................................. . 1

Introduction ............................... 1

Acknowledgments..................... 2

Geologic investigations ................... . 2

Geologic setting............................ 2

Coal petrology of lignite from

Slim Buttes............................... 2

Composition of translucent 

attritus ................

Discussion ...............

Conclusion...............

Literature cited..........

Unpublished 

reports.................

ILLUSTRATIONS

Figure 1. Composition of lignite in upper bench, Olesrud bed

2. Composition of lignite in lower bench, Olesrud bed,

3. Composition of lignite in Mendenhall "rider" bed..,

TABLES

Table 1. Comparison of average composition of Slim Buttes coal beds.with other coal beds mined in 

North Dakota .....................................................................

2. Analyses of coal ...................................................................

3. Composition of uraniferous coal layers...............................................

4. Composition of translucent attritus in uraniferous coal layers ..........................

Page

10

Page

ii

4

5

Page

ABSTRACT

Quantitative coal petrologic studies have been completed on 4 beds of uranium-bearing lignite from the 

Slim Buttes area of Harding County, S. Dak. Comparison of analyses of these deposits with analyses of lignite from commercial deposits suggests that the 

Slim Buttes coal deposits are highly diverse in composition. Relative to most coal deposits, however, all 

of the Slim Buttes coal that was studied has an unusually high uranium content. The studies show that no 

quantitative correlation exists between uranium content and the coal petrologic constituents that are normally determined for coal-type classification and for 

prediction of coal behavior in utilization.

As the coal constituents normally determined are 

to some extent heterogeneous, a further study was 

made of subordinate components. The components of 

translucent attritus were studied particularly, not only 

for selected layers of Slim Buttes lignite, -but also for 

layers of coal from the Goose Creek field in southern 

Idaho. These data are presented for 11 layers of

relatively high uranium content and for 8 associated 

layers that are much less radioactive and approach 

values that are about normal for coal. The results 

of this comparison cast doubt on direct correlation of 

uranium content with the amount of any single microscopic component of coal. A more complex control 

of uranium occurrence in coal is indicated.

It may be significant that the samples richest in 

uranium contain relatively large amounts of humic 

attrital matter resulting from decomposition and microbial decay. One may tentatively conclude that this 

type of organic material is most favorable to uranium 

emplacement.

INTRODUCTION

Uranium-bearing coals in South Dakota, Idaho, 

and Wyoming are being studied by the Geological Survey as possible sources of uranium. The fuel value of the 

coal should favor economic uranium extraction. Field 

reconnaissance and detailed geologic studies have been
followed by exploratory drilling in the Slim Buttes area, 

South Dakota, the Goose Creek area, Idaho, and the 

Red Desert area, Wyoming. Cores from the exploratory drilling have been processed and sampled in the 

laboratory of the Geological Survey to provide close 

correlation of analyses and descriptions of the coal 

and associated rocks as a basis for further petrologic. 

and geochemical research.

The object of these studies is to determine the 

 nature of these uranium-bearing coals and, as far as 

possible, to indicate conditions governing the occurrence of uranium in them. Only brief statements, 

showing general radioactivity profiles (Schopf, 1953) 

and progress in petrologic investigations (Schopf, 

Gray, and Warman, 1953), have previously been given. 

Part of the petrologic research, involving quantitative 

microscopy of coal thin sections from the Slim Buttes 

area, Harding County, S. Dak., and from the Goose Creek 

area, Cassia County, Idaho, is presented in this progress report. Studies of the deposits in these areas and 

in the Red Desert area are continuing. The work is being 

done on behalf of the Division of Raw Materials of the 

U. S. Atomic Energy Commission.

Coal petrologic methods and microanalytic standards developed by Thiessen and his colleagues at the 

U. S. Bureau of Mines (Thiessen, 1931; Thiessen and 

Sprunk, 1935; Thiessen, 1937; and Parks and O'Donnell, 

1949) have been followed in the present study and to 

some extent expanded. These methods of study more 

definitely indicate similarities or differences in the 

plant products that have contributed to the coal than 

standard chemical analyses that are based on empirical 

procedures. However, the two procedures are complementary, each being used to evaluate different properties. 

Thiessen1 s petrologic procedures have been most widely 

applied in the United States, and thus are preferable for our 

use in studying the relationship between plant constituents and uranium content. Most coal beds are not 

uraniferous (see Russell, 1944, 1945; DeMagnee, 1952; 

and Welch, 1954); therefore, this comparison should 

disclose whether coal of unusual plant composition is 

associated with an unusual content of uranium.

Breger and Deul (1952) have shown that almost all of the uranium in weathered lignite from 

the nearby Mendenhall mine is chemically held 

by the organic matter as an organouranium compound or complex, and is not directly associated 

with mineral matter or with other trace elements. 

Because radioactivity profiles of weathered and unweathered lignite are similar (Schopf, 1952, unpublished), it is probable that this condition applies 

generally to radioactive coal of the Slim Buttes 

area. However, the uneven distribution of uranium within a coal bed requires further explanation.

Acknowledgments

Analytic values for air-dry ash and uranium have been determined in the laboratory of 

the U. S. Geological Survey by Alice Padgett, 

Alice Cammerer, and Thomas Murphy under the 

direction of Irving May. Standard analyses of 

coal have been provided by the U. S. Bureau of 

Mines under supervision of Mr. Roy F. Abernethy.

GEOLOGIC INVESTIGATIONS

The uranium-bearing lignite in the Slim Buttes 

area was studied by Denson, Bachnian, and Zeller 

(1951), and results of exploratory core drilling by the 

Geological Survey were reported by Zeller (1952). The 

area was included in the earlier geologic report by 

Winchester and others (1916). Additional core drilling 

was undertaken in 1952 by the Atomic Energy Commission in cooperation with the Bureau of Mines and the 

Geological Survey. J. R. Gill of the Geological Survey 

is preparing a geologic report on the drilling by the 

Atomic Energy Commission. Samples from both programs of exploratory drilling are included in the present report. Hail and Gill (1953) made a reconnaissance 

study of the geology of the Goose Creek area, and 

Mapel and Hail (1953) described the geology of the 

district in detail. Exploratory core drilling was undertaken there by the Geological Survey in 1953, and 

samples from two of these holes are included in the 

present report.

GEOLOGIC SETTING

The uranium-bearing lignite in the Slim Buttes 

area is in the Ludlow member of the Fort Union formation of Paleocene age. The lignite-bearing rocks are 

exposed in the lower part of the Slim Buttes, a prominent topographic feature which is capped by rocks of 

the White River group (Oligocene) and by the Arikaree 

formation (Miocene). Denson, Bachman, and Zeller 

0.951) and Zeller (1952) believe that uranium was emplaced 

in the lignite beds by ground water that had leached uranium 

from the overlying Oligocene and Miocene(?) strata. 

The White River deposits are thick and tuffaceous, 

at most places mildly radioactive, and recently have 

been found to contain carnotite (Gill, 1953). Emplacement of uranium in Slim Buttes coal by ground-water 

movement is suggested by the frequent occurrence of 

uranium in greatest|concentration in the uppermost 

part of the first bed of lignite below the pre-Oligocene 

unconformity.

The uranium-bearing lignite and carbonaceous 

shale in the Goose Creek area are in the Salt Lake formation of probable Pliocene age, a thick sequence made 

up chiefly of volcanic ash and welded tuff. The volcanic ash is slightly uraniferous. Mapel and Hall (1953) 

suggest that uranium had been deposited in the lignite 

and carbonaceous shale by ground water that had 

leached the uranium from the volcanic ash and tuffs.

COAL PETROLOGY OF LIGNITE FROM SLIM BUTTES

Coal petrologic studies thus far have been completed for the 3 coal beds cored in hole SD-10 1 

and 1 bed in hole 16.2 According to recent studies 

by J. R. Gill (personal communication, 1954), the 

upper two beds of hole SD-10 are jointly equivalent to 

the upper bench of the bed formerly worked at the 

Olesrud mine in the SEi sec. 36, T. 18 N., R. 7 E.

1 Core holes designated by numbers prefixed with SD were drilled 

in 1952 and 1953 by the Atomic Energy Commission in cooperation with 

the Bureau of Mines and the Geological Survey.

2 Core holes designated by numbers without a letter prefix were 

drilled by the Geological Survey in 1951.
The third bed is equivalent to the lower bench of coal 

at the Olesrud mine. The coal bed tested in hole 16 

is equivalent to the thin bed in the outcrop along the 

west side of the Slim Buttes. This bed is located some 

distance above the Mendenhall bed of the nearby 

Mendenhall strip mine (NWiSEi sec. 1, T. 17 N., 

R. 7 E.) and is referred to as the Mendenhall "rider. " 

The results of these studies are illustrated diagrammatically in figures 1-3.

Uranium-bearing lignite in the Slim Buttes area 

usually shows definite, nearly regular concentration 

of uranium at the top of the bed, as is illustrated by 

the Mendenhall "rider" bed in figure 3. In hole SD-10, 

the Olesrud group of beds is exceptional, for the uranium is irregularly concentrated in several layers 

(figs. 1 and 2). Apparently, this irregular distribution 

is related to a cause other than downward percolation 

of ground water. For this reason it presents an opportunity to test the relationship of the petrologic composition to uranium content under circumstances that 

might be unusually revealing. It was hoped that at 

this locality a direct petrologic correlation would be 

apparent and so indicate which coal constituents or 

components were most receptive to emplacement of 

uranium.

The average composition of these Slim Buttes 

coal beds is presented in table 1 in comparison with 

some of the available petrologic data on other lignite 

deposits of North and South Dakota that contain little 

or no uranium. 3 If any general feature of petrologic 

composition is related to the unusual association of 

uranium in coal, such a comparison should reveal it, 

but none is apparent. The most striking feature of 

Slim Buttes coal is the wide range in petrologic composition of the different beds.

An unusually high content of opaque attritus 

seems to be distinctive for the coal from hole 16 

(fig. 3). The high anthraxylon content of the thin

3None of 21 lignite samples from 4 companies producing in 

North Dakota in 1951 and 1952 showed more than 0.001 percent equivalent uranium, according to TUP reports 1324 and 1590-93, and TWC 

report 1803 of the Geological Survey laboratory.

second coal bed in hole SD-10 indicates an extremely 

woody lignite (fig. 1). The 11 percent of fusain found 

in the upper coal bed in hole SD-10 (fig. 1) is also 

exceptional, particularly as it is linked with a high, 

but not extraordinary, occurrence of opaque attritus. 

There is, however, a considerable amount of pyrite 

associated with the upper coal bed in this drill hole, 

which suggests at least temporary periods of increased 

anaerobic bacterial activity (Schopf, 1952) during the 

period of peat accumulation. The marked diversity of 

composition undoubtedly signifies differences in conditions of accumulation having paleoecologic significance 

 in the varieties of plants, their accumulation and 

decay in peat formation, and in their influence on 

diagenetic changes. Although these topics merit further consideration, they are beyond the range of this 

preliminary report.

Standard coal analyses were obtained for all cores 

of coal beds that might be of economic interest. Analyses of samples from hole SD-10 and hole 16 are given 

in table 2. Older analyses are given by Winchester 

and others (1916, p. 42-3). Analyses of lignite from 

a few recently operated mines in North Dakota, and 

one recent analysis of impure coal from Goose Creek, 

are included in table 2 for comparison. The usual 

evaluations of coal quality, which are based almost 

entirely on chemical analyses such as those in table 2, 

do not indicate the variety of organic materials composing the beds. For example, analysis of the coal 

from hole 16, which is unusually high in opaque attritus, 

shows, on a moisture and ash-free basis, fixed carbon 

almost identical to the other coal from the Slim Buttes 

area and only about 2 percent more total carbon.

The similarity of the coal analyses, regardless of marked differences in organic makeup, 

is not surprising because the materials contributed 

by different plants may be similar in chemical 

properties. However, these materials react in 

different ways during coalification. Opaque attritus 

and fusain generally indicate a greater concentration of carbon, but this expected effect can be 

counterbalanced in a sample by other materials 

of more volatile composition. The relation between 

plant composition (type) and advancing incoalation 

(rank) is least understood in coal of low rank

Table 1. Comparison of average composition, in percent, of Slim Buttes coal beds with other coal

beds mined in North Dakota

Source Depth 

(feet) Anthraxylon Translucent attritus

Opaque 

attritus Fusain

Uraniferous coal of Slim Buttes

Hole 16 (Mendenhall "rider") 

Hole SD-10 (top split of Olesrud bed, upper bench) .

Hole SD-10 (bottom split of Olesrud bed, upper bench) .

Hole SD-10 (Olesrud bed, lower

bench) .

333-92

3rM

321.37

381.07

53

50

75

56

17

32

23

31

24

7

1

6

3

11

1

7

Lignite mined in North Dakota

Burleigh lignite 

Lehigh lignite 

Beulah lignite 

Baukol-Noonan lignite 

63

59

53 

56

31 

36

oc

33

5

3

15

4

1

2

6

7
COMPOSITION, IN PERCENT URANIUM 

Total anthraxylon Translucent attritus Opaque 

attritus

90 percent of cool thickness studied in thin section

Fusain

Megafusain Micrafusain

Visible 

impurities

Total composition, in percent, for layers between 381.07ft and 386.56ft 

Pre-vitram (woody) 38.0 Opaque attritus 5.3 

Attrital anthraxylon 16.2 Fusain 6.8 

Translucent attritus 30.4 Visible impurities 3.3

Ash prof

(air-dry b

Total anthraxylon, 69.5

Pre-vitrain 

(woody), 60.3

Attrital 

anthraxylon, 9.2

*TE-43 V//////////////////J&& 

- ^ ^ /< f f ^revwi

Total onthroxylon, 50.1___

Pre-vitrain Attrital 

(woody), 34.4 anthraxylon, 15.7

Translucent 

attritus, 25.7

l^^^sSSs^M

Translucent 

attritus, 42.9

I^^S^^

Opaque 

attritus, 3.4

D

Opaque 

attritus, 1.5

1 D

Fusain, 

1.5

1

Fusoin, 

4.9

Visible impurities, 

0.0

Visible impurities, 

0.7

1

Scale for composition of individual layers, in percent 

0 20 100

Figure 2. Composition of lignite in lower bench, Olesrud bed, drill hole SD-10, Slim Buttes area, Ha
Totol onthroxylon

COMPOSITION, IN PERCENT 

333.60 fK 

Loyer I 

Loyer 2,

333.92 f \J

Loyer 3

335.52 ft

Pre-vitrain Attritol 

(woody) anthraxlyon

Translucent 

attritus

341.96 ft

j Tabs indicate positions of thin sections sampling attrital coal. 

1 15.3 percent of attrital coal is represented in sections

Opaque 

attritus

Fusain Visible Ash 

impurities (air-d

Microfusain /Impure shaly coal

Megafusain

Dark clay'

Pyrite and clay

Pyrite

TE-5

TE-6

TE-7

TE-8

TE-9

TE-IO

TETE-12

TE-13

Totol composition, in percent, for loyers between 333.60ft ond 341.96ft

Pre-vitroin (woody) 39.15 Opaque ottritus 25.4

Attritol onthroxylon 11.53 Fusoin 3.3

Translucent attritus 16.1 Visible impurities 4.5

Scale far composition of individual layers, in percent 

0 20 100

Figure 3. Composition of lignite in Mendenhall "rider" bed, hole 16, Slim Buttes area, Harding Cou
Table 2. Analyses of coal

[Bureau of Mines lab. aos. Basis of reporting: AR, as received; MF, moisture free; MAP, moisture and ash free]

Proximate 

Ultimate

Moist ureVolatile 

Fixed car

Sulfur

Fusibility 

of ash,°F

Specific gi

Initial c 

Softening 

Fluid -

cavity- -

Total 

leformation 

r 

E-9832

A R

44.2 

20.2 

25.7 

9.9 

.01 

.24 

 32 

.6 

7-0 

32.8 

.4 

49-3 

5470

M F

36.3 

46.0 

17-7 

.02 

.43 

.57 

1.0 

3-7 

58.8 

 7 

18.1 

9790

M A F

44.1 

55-9

.02 

.52 

 70 

1.2 

4.5 

71.4 

.8 

22.1 

11890

1980 

2020 

2130 

1.65

E-9933

A R

43.9 

21.6 

25.5 

9.0 

.01 

.41 

.42 

.8 

7-1 

33-4 

.4 

49.3 

5640

M F

38.4 

45.5 

16.1 

.01 

 74 

 74 

1.5 

3-9 

59.5 

.8 

18.2 

10050

M A F

45.8 

54.2

.02 

.88 

.89 

1.8 

4.6 

70.9 

 9 

21.8 

11970

1970 

2020 

2060 

1.63

D-71570

A R

41.8 

22.0 

26.1 

10.1

3 .8 

6.9 

34-7 

.4 

47.1 

5790

M F

37-9 

44.8 

17-3 

?.07

2 " 29 

*1.25 

4 1.4 

3.8 

59-7 

.8 

17.0 

9950

M A F

45.8 

54.2

"~To8

/ ^

'l.5C 

8 1.7 

4.6 

72.2 

.9 

20.6 

12030

2050 

2100 

2180

C-324421

A R

36.7 

29.3 

28.5 

5-5

.6 

6.9 

42.0 

.6 

44.4 

6930

M F

46.3 

45.0 

8.7

.9 

4.4 

66.3 

1.0 

18.7 

10960

2500

M A F

50.7 

49-3

1.0 

4.8 

72.6 

1.1 

20.5 

12000

C-654

A R

35-5 

26.6

31-7 

6.2

 5

7250

M F

41

49

9

1124

'Total sulfur of D-71570. Total of duplicate dry sample is 

"Total sulfur of D-71570. Total of duplicate dry sample is 

'Analyses from U. S. Bureau of Mines Bull. 482, p. 23 (Selvig, Ode, Parks, and O'Donnell, 1950). 

*Forms of sulfur determined from a duplicate dry sample corresponding to D-71570. 

'Total sulfur of D-71570.

Source of samples:

E-9832. Top and middle Slim Buttes beds, 317 feet 4% inches to 322 feet 6% inches; hole SD-10.

E-9933. Lower Slim Buttes coal bed, 381 feet '/, inch to 386 feet &/t inches; hole SD-10.

D-71570. Mendenhall "rider"(?) bed, 333 feet 7>/t inches to 341 feet 11% inches; hole 16.

C-32442. Burleigh strip mine, Burleigh County, N. Dak.; coal bed face sample.

C-65444. Noonan bed, Baukol-Noonan mine, Divide County, N. Dak.; mine-run composite sample.

C-46606. Coteau bed, Velva mine, Ward County, N. Dak.; mine-run composite sample

E-28432. Goose Creek impure coal, 243 feet 6'/. inches to 247 feet 8% inches; hole 2.
that has been only slightly metamorphosed. The 

analyses of commercial deposits of North and 

South Dakota appear to indicate coal of somewhat 

higher rank than the beds of the Slim Buttes.

The petrologic charts (figs. 1, 2, and 3) illustrate 

the layer-by-layer distribution of all the coal constituents, impurities, ash, and uranium. These results, 

based as they are on a succession of diverse layers, 

do not suggest a direct correlation between uranium 

content and coal petrographic constituents. The chemical analyses for uranium are the basis for the uranium 

profiles presented on the right in each of the three 4 

figures. The laboratory radioactivity profiles (p/m /g) 

and air-dry ash determinations for successive layers 

are also superimposed on the uranium profiles in 

figures 1 and 2. The ash profiles suggest a very slight 

increase of ash in several of the more radioactive 

layers. Generally, the radioactivity measurements 

closely parallel chemical determinations of uranium 

for this type of material. Where chemical analyses 

were made by combining laboratory radioactivity 

samples, the results suggest that the uranium is distributed even more irregularly than is indicated by the 

profiles based on the larger chemically determined 

samples.

COMPOSITION OF TRANSLUCENT ATTRITUS

In order to test further for a possible correlation 

between microscopically visible plant materials and 

degradation products, it is principally necessary to 

identify and separate the various components of translucent attritus. This finely particulate, nonopaque 

fraction of coal can vary greatly in amount between 

different samples and is the most heterogeneous of the 

constituents. According to the standard coal petrologic procedure (Parks and O'Donnell, 1949), translucent attritus is determined by difference after 

anthraxylon, fusain, and opaque attritus have been 

determined by direct transect measurements. It is 

usually described qualitatively. The refinement of the 

process of quantitatively analyzing the translucent 

attritus requires more time and painstaking observation at higher microscopic magnification than normally 

is practicable for study of an entire coal bed. Data 

comparable to that presented in the following paragraphs, concerning the quantitative occurrence of 

materials composing translucent attritus, have not 

been previously presented in coal petrologic 

literature.

The relation between uranium content and 

the composition of coal layers was studied in 

4 SD-10 coal layers of relatively high uranium 

content and compared with 5 layers of low uranium content. These layers are marked by 

asterisks at the left margin of figures 1 and 2. 

A similar but briefer study was made of

p/m/g =pulses per minute per gram. For this purpose a coarsely 

crushed sample is placed in a cup surrounding a thin-vailed GeigerMiiller tube (Victoreen 1B85) and pulses recorded by a standard 

64 sealer. Net pulses per minute pet gras» are determined in duplicate, 

and averaged, using roughly similar volumes of sample for duplicate 

determinations. Introduction pf the weight factor io calculating results 

apparently compensates to some extent for natural variations in density 

aq *«}J £Mor Taiatioos in. sample volonn* occasioned tiy a minimum "°Y. 

procedure ih sairfple preparation.

6 layers of high radioactivity from Goose Creek 

hole 2 and 3 layers of low radioactivity from Goose Creek 

hole 3A. The results of these studies are given in 

tables 3 and 4. Each set of samples is arranged in detail in 

order of decreasing uranium content. Table 3 presents the distribution of all identified constituents or 

components as percentages of the individual layers; 

table 4 presents the distribution of the identified components of the translucent attritus as percentages of the 

total translucent attritus alone. In interpreting table 4 

it should be borne in mind that translucent attritus 

makes up from about 25 to 55 percent of the layers of 

the lignite from the Slim Buttes area and over 70 percent of all layers in the Goose Creek deposit. Percentages 

of total translucent attritus in each layer studied are 

given at the bottom of each column in table 4.

The Goose Creek coal is of a highly attrital or 

nonbanded type and contrasts strongly, in appearance 

and petrologic composition, with the banded lignite of 

the Slim Buttes area. Highly and slightly radioactive 

samples from different Goose Creek drill holes are 

indistinguishable in appearance, but in radioactivity 

the contrast is more pronounced than in Slim Buttes 

material. The most radioactive layers of the bed in 

hole 2 are centrally and somewhat irregularly distributed without apparent fixed relation to the top of 

the coal bed.

The different kinds of organic particles are more 

uniformly dispersed in nonbanded carbonaceous deposits such as oil shale and cannel coal than in banded 

coal. As the Goose Creek deposits are essentially 

nonbanded, adequate analytic studies require somewhat 

fewer thin sections. The Goose Creek data are based 

on studies at high magnification of one or two thin 

sections from each of the arbitrarily selected layers. 

The composition was determined in detail from each 

of 20 to 30 fields that were distributed at predetermined 

uniform intervals across the thickness of coal included 

on each thin-section slide. Anthraxylon was determined 

by normal transect procedure, and the results from 

both transects were combined to yield data comparable 

to that available for the selected layers of Slim Buttes 

coal. The method seems suitable for detailed comparison of many of the very fine textured carbonaceous 

deposits that differ from banded coal.

The data presented in these tables deserves a 

more extensive discussion than can be given here. 

Calculations have been reported to two places in all 

instances so that an indication of relative abundance 

of very minor elements might be reflected. Some of 

these minor elements, such as disseminated pyrite, 

may signify differences in decomposition processes. 

Other components, such as spore coats or fungal 

sclerotia that have a striking appearance under the 

microscope, are shown to be quantitatively unimportant.

DISCUSSION

It is very doubtful that a direct correlation exists" 

between any single coal component and uranium content. 

The presence of the greatest amount of yellow waxy 

matter (14 to 25 percent) in the most radioactive 

samples (Goose Creek coal, hble 2) seems most 

sugtjestivef Virtually all of the waxy matter in this 

Goqs.e,Creek coal is similar to the waxy amorphous 

.matter that predominates In the most'highly organic
Table 3. Composition, in percent, of uraniferous coal layers

Components

Anthraxylon:

Total 

Translucent attritus:

Total 

Spores, pollen, cuticle 

Total yellow waxy matter 

Transparent organic matter 

Fungus spores 

Fungal sclerotia 

Brown matter with traces of 

semifusain fragments 

Fusain:

Total 

Visible mineral impurities:

Clayey minerals 

Total 

Total 

Uranium determined or estimated 

ppm 

Banded coal-layer samples, Slim Buttes hole SD-10

"Hi

TE-16

16.48 

16.08

32. 56

0.83 

46.99

47.82

f 0.24 

.13 

1.72

2.09

0.01

0.08 

.40 

0.48

5.56

4.42 

3.80

8.22

0.10 

.12 

.0 

0.22

99.81 

377

eh" radioactivity

TE-43

60.25 

9.24

69.49

1.26 

18.97

20.JL5

0.13 

.07

3.76

3.96

0.04

0.05 

.13

0.98

3-35

0.0 

1.47

1.47

0.15 

Tr. 

 15 

0.15

99.81 

150

TE-31

39-48 

12.43

51.91

2.20 

38.66

40.86

0.21 

.03 

1.94

2.18

0.10

0.04 

.23

0.27 

0.84

1.43 

1.36

2.79

0.02 

.06 

.19 

0.27

99.99 

150

TE-24

48.40 

10.81

59.21

0.62 

31.10

31.72

0.07 

.06 

2.00

2.13

0.0

0.02 

.0

0.02

0.61 

1.14

0.0 

.14

0.14

0.50 

.15 

3-46 

4.11

99-98 

134

Low radioactivity

TE-37

18.66 

16.05

34.71

0.27 

36.37

36.64

0.23

.0 

2.59

2.82

0.62

0.01 

.0

0.01 

7.18

10.02

5-14 

2.08

7.22

0.0 

.0 

.07 

0.07

100.03

21

TE-22

59.58 

11.95

71.53

0.25 

23.79

24.04

0.04 

.02 

1.07

1.13

0.02

0.03 

.02

1.31

0.0 

1.15

1.15

0.0 

.01 

.08 

0.09

100.04 

20

cTE-10

53.96 

18.02

71.98

0.55 

20.92

21.47

0.05 

.07 

.72

0.84

0.02

0.03 

.05 

0.08

1.43

2.33 

0.83

3.16

0.0 

.0 

.0 

0.0

99.43 

19

' TE-40

34.37 

15.76

50.13

0.78 

32.56

33.34

0.12 

.20 

5.04

5.36

0.0

0.0 

.0

1.96

1.51

1.10 

3.77

4.87

0.63 

.0 

 03 

0.66

99-99 

16

TE-40

46.95 

17.77

64.72

0.38 

23.19

23.57

0.27 

Tr. 

1.02

1.29

0.04

0.03 

.03 

0.06

2.65

1.66 

3.02

4.68

Tr. 

Tr. 

.0 

.Tr.

99.96 

3

Nonbanded or high

"Very high' radioacti

L-8

2.40

74.57

17.38

0.68

0.19 

.0

0.19 

Tr.

0.0

0.29 

2.14 

.0 

2.43

99-39 

^103

L-6

1.60

67-31

24.70

2.95

0.30 

.60

0.90 

Tr.

0.0

0.03 

1-57 

.0 

1.60

99-98 

 '896

L-7

2.90

71.85

17.5C

1.65

0.19 

.0

0.19 

Tr.

0.0

0.0 

3.50 

.0 

3". 50

99-83 

1 753

L

1

Estimated from radioactivity determinstions

Table 4. Composition, in percent, of translucent attritus in uraniferous coal layers

Components

Total 

Spores, pollen, cuticle 

Total yellow waxy matter 

Fungus spores 

Fungal sclerotia ----- -

Brown matter with traces of 

Semifusain fragments 

Uranium determined or estimated 

ppm 

Approximate amount of layer represented by the translucent 

attritus analyzed -percent 

Banded coal-layer sam

"Hi

TE-16

1.47 

83,12

84.59

0.43 

.24 

3.04

3.71

0.15 

.72

0.87 

9.84

99.90 

377

56.5

eh" radioactivity

TE-43

4.90 

73.87

78.77

0.51 

.28 

14.65

15.44 

0.17

0.21 

.50

3.85

99.99 

150

25.7

TE-31

4.93 

86.66

91.59

0.47 

.08 

4.36

4.91

0.10 

.40

0.60 

1.88

99.99 

150

44.6

TE-24

1.76 

87.84

89.60

0.19 

 17 

5.64

6.00

0.06 

.0

1.79

100.00 

134

35.4

pies, Slim Buttes hole SD-10

Low radioactivity

TE-37

0.56 

75.75

76.31

0.48 

.0 

5.40

_5_.88

0.01 

.0

14.96

100.01 

21

48.0

TE-22

0.92 

88.39

89.31

0.20 

.08 

3.97

4.25

0.12 

.08

4.89

99.95 

20

26.9

TE-16

2.27 

86.86

89.13

0.21 

.28 

3.01

3.50

0.24 

.23

0.47 

5.90

99.90 

19

24.1

TE-46

1.83 

76.02

77.85

0.29 

.46 

11.77

12.52

0.0 

.0

0.0 

4.59

16 

42.8

TE-40

1.36 

83.07

84.43

0.98 

.01 

3.64

4.63

0.12 

.09

0.22 

9.50

99.91 

3

27.9

Nonbanded or high

"Very high" radioactiv

L-8

79. 5C

18.53

0.21 

.0

0.21

Tr. 

99.8S

'1103 

94.3

L-6

69.74

25.59

0.41 

.60

1.01 

Tr.

*896 

97-5

L-7

78.31

19.15

0.21 

.0

0.21 

Tr.

*753 

91.8

L

1 Estimated from radioactivity determinations.
laminae of oil shale in the Green River formation. 

However, no direct correlation with estimated uranium 

content (based on laboratory radioactivity measurements) 

is apparent among the several adjacent samples from 

Goose Creek hole 2; neither does the waxy amorphous 

matter nor the total of yellow waxy matter and waxy 

amorphous matter of the "high" and "low" Slim Buttes 

layers indicate a direct correlation.

Some other more or less systematic differences 

can also be noted from tables 3 and 4. For example, 

the low radioactivity samples from Goose Creek hole 3A 

all contain more anthraxylon than high radioactivity 

samples from Goose Creek hole 2. This is very probably indicative of a difference in decay. The types of 

fungus spores in these samples also differ. It is clear, 

however, that none of the differences in petrologic 

composition can be taken as an indication of the concentration of uranium.

If it is assumed that the uranium in all the coal 

components is combined or taken up by the organic 

matter in the same way, the correlation of petrologic 

components with the variations in uranium content 

would appear to be highly complex and probably also 

dependent on other factors. The particular significance 

of this series of samples rests on the fact that none of 

them appear to owe their high or low uranium content 

to their relative position within the bed.

An unusually high uranium content at the top of 

the Mendenhall "rider" coal in hole SD-8 has been 

noticed in the course of processing core from test 

drilling in the Slim Buttes area. This layer, less than 

3 inches thick, is the only lignitic material received 

from the Slim Buttes area that is as highly radioactive 

as that from Goose Creek hole 2. A comparison of 

translucent attritus components of the thin layer from 

hole SD-8 with samples from hole SD-10 and hole 16 

seemed of interest because the sample (TE-2) from 

hole SD-8 is in normal top-preferential position. A 

summary of rounded totals from this unusual layer, 

expressed on the whole-coal basis for comparison 

with table 3, is as follows: anthraxylon, 35 percent; 

humic matter, 53 percent; red resins, 0. 5 percent; 

brown matter, 2.3 percent; opaque attritus, 1.5 percent; fusain, 4 percent; visible impurities, negligible. 

Translucent attritus comprises nearly 60 percent of 

the layer, and the layer contains about 900 ppm 

uranium.

This sample and the richest sample from 

hole SD-10 (TE-16; 380 ppm U) have the highest 

amounts of humic matter (53 and 48 percent) and 

fungus material (0.49 and 0.48 percent) among the 

Slim Buttes samples. Humic matter is largely the 

product of extensive decomposition of plant materials. 

The types of fungi observed are chiefly responsible for 

processes of aerobic decay. The very rich series of 

samples from Goose Creek hole 2 has already been 

noted as exceptionally rich in products of plant decay, 

and sclerotium-forming fungi also are present as they 

are in the Slim Buttes coal. Obviously, this 

relationship is not likely to lead to an exact 

basis for the prediction of uranium occurrences, 

but the data suggest more than a fortuitous coincidence. Further investigation of the relationship will require the collection of more data 

that reflect on the paleoecology of coal formation

and the related processes of aerobic and anaerobic 

microbial decay.

CONCLUSION

It is conceivable that plant material that has 

been most subjected to decay is the most receptive 

to uranium emplacement. This working hypothesis 

would seem consistent with the almost sapropelic condition of Goose Creek material of high 

radioactivity, as well as the most radioactive 

Slim Buttes material. It would also seem generally 

consistent with the usual dominance of humic substances 

in the organic matter of radioactive marine deposits. 

The coal of low radioactivity in Goose Creek hole 3A, 

however, indicates that extensive decay can at most 

only predispose the coal to uranium emplacement.

LITERATURE CITED

DeMagnee, I., 1952, Observations sur la radioactivite des horizons marins du Westphalien 

Beige: Congres, Troisieme, pour 1'Avancem. 

des Etudes de Stratig. et. de Geol. du 

Carbonif., Heerlen Juin 25-30, 1951, v. 2, 

p. 429-434.

Parks, B. G., and O'Donnell, H. J., 1949, 

Determination of petrographic components of 

coal by examination of thin sections (with 

discussion, and text corrections omitted from 

AIME Tech. Paper 2492, Nov. 1948): Am. Inst. 

Min. Met. Eng. Trans., Coal Division, 1948, 

v. 177, p. 535-555.

Russell, W. L., 1944, The total gamma ray 

activity of sedimentary rocks as indicated by 

Geiger counter determinations: Geophysics, 

v. 9, no. 2, p. 180-216.

_______1945, Relation of radioactivity, organic 

content, and sedimentation: Am. Assoc. Petroleum Geologists Bull. 29, p. 1470-1493.

Schopf, J. M., 1952, Was decay important in 

origin of coal?: Jour. Sed. Petrology, v. 22, 

p. 61-69.

Selvig, W. A., Ode, W. H., Parks, B. C., 

and O'Donnell, H. J., 1950, American lignites: 

geological occurrence, petrographic composition, 

and extractable waxes: U. S. Bureau of Mines 

Bull. 482, p. 63.

Thiessen, Reinhardt, 1931, Microscopic examination 

of coal; Description and properties of coal, 

in Fieldner, A. C., and others, Methods 

and apparatus used in determining the gas, 

coke, and by-product making properties of 

American coals: U. S. Bur. Mines Bull. 344, 

p. 22-32, 53-83.

_______1937, What is coal?: 17th Engineers' 

Meeting, Appalachian Coals, Inc., Cincinnati, 

Ohio, 38 p. (reprinted June 1947, omitting 

discussion, as U. S. Bur. of Mines Inf. 

Circ. 7397, 53'p.).

Thiessen, Reinhardt, and Sprunk, G. C., 1935, 

Microscopic and petrographic studies of certain 

American coals: U. S. Bur. Mines Tech. 

Paper 564.

Winchester, D. E., Hares, C. J., Lloyd, E. R., and 

Parks, E. M., 1916, The lignite field of northwestern 

South Dakota: U. S. Geol. Survey Bull. 627, p. 169.
UNPUBLISHED REPORTS

Breger, I. A., and Deul, M., 1952, Status of investigations on the geochemistry and mineralogy of 

uraniferous lignites: U. S. Geol. Survey Trace 

Elements Inv. Rept. 284, p. 1-80.

Denson, N. M., Bachman, G. O., and Zeller, H. D., 

1951, Summary of new information on uraniferous 

lignites in the Dakotas: U. S. Geol. Survey Trace 

Elements Memo. Rept. 175.

Gill, J. R., 1953, Uranium minerals in Cedar Canyon, 

Harding Co., S. D., in_ Search for and geology of 

radioactive deposits; semiannual progress report 

Dec. 1, 1952 to May 31, 1953: U. S. Geol. Survey 

Trace Elements Inv. Rept. 330, p. 124-125.

Hail, W. J., Jr., and Gill, J. R., 1953, Radioactive carbonaceous shale and lignite deposits in the Goose Creek 

district, Cassia County, Idaho: U. S. Geol. Survey 

Trace Elements Inv. Rept. 272, p. 1-34.

Mapel, W. J., and Hail, W. J., 1953, Uraniumbearing carbonaceous shale and lignite in the 

Goose Creek district, Cassia County, Idaho, Boxelder County, Utah, and Elko County, Nev.: U. S. Geol. 

Survey Trace Elements Inv. Rept. 339, p. 1-57.

Schopf, J. M., 1952, Core processing, in Search for 

and geology of radioactive deposits; semiannual 

progress report'June 1 to Nov. 30, 1952: U. S. Geol. 

Survey Trace Elements Inv. Rept. 310, p. 156- 

162.

_______1953, Core processing, in Search for and 

geology of radioactive deposits; semiannual progress 

report Dec. 1, 1952 to May 31, 1953: U. S. Geol. 

Survey Trace Elements Inv. Rept. 330, p. 153- 

159.

Schopf, J. M., Gray, R. J., and Warman, J. C., 1953, 

Coal petrographic studies on Dakota lignite, in Search 

for and geology of radioactive deposits; semiannual 

progress report Dec. 1, 1952 to May 31, 1953: 

U. S. Geol. Survey Trace Elements Inv. Rept. 330, 

p. 125-138.

Welch, S. W., 1954, Radioactivity of coal and associated 

rocks in the anthracite fields of eastern Pennsylvania: 

U. S. Geol. Survey Trace Elements Inv. Rept. 348, 

p. 1-31.

Zeller, H. D., 1952, Results of core drilling of uraniumbearing lignite deposits in Harding and Per kins Counties, S. D., and Bowman County, N. D.: U. S. Geol. 

Survey Trace Elements Inv. Rept. 238, p. 1-104.

10

INT.-DUP. SEC., RASH., B.C. 66283
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