Bureau of Mines Report of Investigations/l976 

Geology of the Mary Lee Group 

of Coalbeds, Black Warrior Coal 

Basin, Alabama 

UNITED STATES DEPARTMENT OF THE INTERIOR 
Report of Investigations 8189 

Geology of the Mary Lee Group 

of Coalbeds, Black Warrior Coal 

Basin, Alabama 

By G. W. Murrie, W. P. Diamond, and S. W. Lambert 

Pittsburgh Mining and Safety Research Center, Pittsburgh, Pa. 

UNITED STATES DEPARTMENT OF THE INTERIOR 

Thomas S. Kleppe, Secretary 

BUREAU OF MINES 

Thomas V. Falkie, Director 
This publication has been cataloged as follows: 

hlurrie, Gary W 

Geology of the Mary Lee Group of coalbeds, Black Warrior 

coal basin, Alabama / by G. W. Wurrie, W. P. Diamond, and 

S. W. Larnbert. [Washington] : beau of bhines, 1976. 

49 p. : maps, diagrams ; 26 cm. (Report of investigati~ns 

Bureau of Xlines ; 8189) 

Bibliography: p. 41-42" 

1. Coal - Geology - Alabama - Hlack Warrier coal basin. I. 

Diamond, William P., joint author. 11. Lambert, Stephen K., joint 

author. 111. United States. Bureau of hlines. IV. Title. V. 

Series: United States. Bureau of hlines. Report of investigations - Bureau of >lines ; 8189. 

TN23.U7 no. 8189 622.06173 

U.S. IJept. of the Int. I.ibrary 
CONTENTS 

Page 

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

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

Acknowledgments ........................................................ 4 

Previous work ........................................................... 4 

Regional structure ...................................................... 4 

Black Warrior coal basin structure ................................. 4 

Cleat and inclined fractures in the Mary Lee coal .................. 7 

Mary Lee Group coal stratigraphy ........................................ 11 

New Castle coal .. ................................................. 12 

Mary Lee coal ...................................................... 12 

Blue Creek coal .................................................... 22 

Jagger and Ream coals .............................................. 26 

Depositional setting of the Mary Lee Group ......................... 26 

Structural control bf Mary Lee Group sedimentation ...................... 30 

New Castle coal .................................................. 30 

Mary Lee coal ...................................................... 30 

Blue Creek coal ..............o..................................... 31 

Geologic factors influencing mining operations .......................... 31 

Strata overlying the Mary Lee coalbed .............................. 31 

Methane gas content and degasification ............................. 32 

Surface joint and cleat measurements .................................... 34 

Field methods and data compilation ............................... 36 

Prediction of subsurface cleat orientation^........^............... 36 

Origin of joints and cleats ....................................... 39 

Sunrmary ................................................................. 40 

References .............................................................. 41 

Appendix A.--Surface joint reailings of individual quadrangles ........... 43 

Appendix B...Surface cleat readings of individual quadrangles ........... 47 

ILL TRATIONS 

Map of study area .................................................. 2 

Location of study area within the Black Warrior basin .............. 3 

Structure map drawn on the base of the Mary Lee coalbed ............ 5 

Strike of normal faults in the Black Warrior coal basin ............ 6 

Rose diagrams of cleat strikes in seven mines operating in the Mary 

Lee coalbed ...................................................... 8 

Rose diagrams of strikes of cleat and inclined fractures in the Oak 

Grove and Blue Creek mines ....................................... 9 

Mines in the Mary Lee coalbed ...................................... 10 

Generalized stratigraphic column showing the Mary Lee Group coalbeds and adjacent strata ......................................... 11 

New Castle coal isopach ..............................*............. 13 

New Castle-Mary Lee interval isopach ............................... 14 

Isopach of sandstone in the New Castle-Mary Lee interval ........... 15 

Map showing location of regional cross section lines ............... 16 

Cross section D . D' ............................................... 17 

Cross section E . E' ............................................... 18 
ILLUSTRATIONS . -Continued 

Page 

Cross sectionA -A' ............................................... 19 

Cross section B . B' ............................................... 20 

Mary Lee coal isopach .............................................. 21 

Map of volatile content of the Mary Lee coalbed .. .................. 23 

Blue Creek coal isopach ............................................ 24 

Cross section C . C ' ............................................... 25 

American-Mary Lee interval isopach ................................. 27 

Combined isopach of the Mary Lee Group of coalbeds ................. 29 

Depth of coalbed versus gas content ................................ 32 

Overburden isopach of strata overlying the Mary Lee coalbed ........ 33 

Rose diagrams of surface joints for 35 quadrangles ................. 35 

Composite rose diagram of principal surface cleat trends ........... 36 

Composite rose diagram of principal surface joint trends ........... 36 

Composite rose diagram of principal underground cleat trends ....... 37 

TABLES 

1 . Methane resources .................................................. 34 

2 . Fundamental regional systems from directional data .................. 37 
GEOLOGY OF THE MARY LEE GROUP OF COALBEDS, 

BLACK WARRIOR COAL BASIN, ALABAMA 

by 

G. W. Murrie, W. P. Diamond, and S. W. Lambert 1 

ABSTRACT 

A geologic study of the Mary Lee Group of coalbeds in the Black Warrior 

coal basin was undertaken to examine coal stratigraphy and determine regional 

trends and extent of the coalbeds. The area investigated encompasses 

835 square miles in Jefferson, Walker, and Tuscaloosa Counties, Ala. More 

than 700 core logs were used to construct a structure map, coal, interval, 

and overburden isopachs, and cross sections. 

There is evidence that structure affected sedimentation. Coalbed isopachs indicate the Mary Lee Group was deposited in fluvial-deltaic and lowlying coastal plain environments. The Mary Lee coalbed is the only coalbed 

which is continuous throughout the area, commonly with two benches which have 

a combined thickness of 2 to 12 feet. The Mary Lee coalbed changes rank in 

the basin from high- through medium- to low-volatile coal. The methane gas 

potential of the Mary Lee Group coals is estimated to be greater than 1 trillion cubic feet. 

There is an excellent correlation between the orientation of surface 

cleatswiththose measured undergroundin the Mary Lee coalbed. The face cleats 

roughly parallel the axes of the area's folds and trend northeast-southwest. 

INTRODUCTION 

The investigation of the geology of the Mary Lee Group, Upper Pottsville 

age, was initiated with an evaluation of the methane content of the coalbeds 

of this group (6).' - Over 700 core logs were used in the methane study and the 

maps, cross sections, and stratigraphic data provide a valuable geological 

framework heretofore unavailable for this part of the Warrior basin. All 

these data provide information with practical application for the coal mining 

industry as well as providing a basis for further geological investigations. 

This report is part of a continuing effort of the Bureau of Mines to 

determine the factors that affect the safety of mining coal in U.S. coalbeds. 

In the course of these investigations it has been established that significant 

quantities of methane may be recovered from coalbeds before and during mining. 

Geologist . 'underlined numbers in parentheses refer to the list of references preceding 

the appendixes. 


to be within the Warrior field Q). The Warrior coalfield now accounts for 

approximately 93 pct of Alabama's coal production. The Mary Lee Group is the 

most economically important of all the coal groups, containing three times 

more coal reserves than the combined estimate for the other three Alabama 

coalfields. 

ACKNOWLEDGMENTS 

The authors acknowledge the cooperation and assistance of several coal 

companies and their personnel without whose support this investigation could 

not have been completed. Core data and permission for mine surveys were 

supplied by the following: Charles Hager, vice president of mining; Jack 

Morris, chief geologist; Gary Myers and Norman Bowne, geologists, Jim Walter 

Resources; Douglas Cook, vice president of engineering-mines, Alabama 

By-Products Corp.; E. J. Files, general superintendent, and Henry Kerley, 

chief mining engineer, U.S. Steel Corp.'s Southern District; and W. H. Haynes, 

manager of fuels, and Harry Raykes, mining engineer, Southern Services Corp. 

Credit is also due to T. W. Daniel, J. A. Drahovzal, F. E. Evans, Jr., and 

W. E. Ward 11, geologists, Geological Survey of Alabama, for joint surveys and 

general geological data collected under a grant from the Bureau of Mines. 

PREVIOUS WORK 

The first investigations of the Alabama coalfields were initiated in 

1886 by McCalley (2) of the Geological Survey of Alabama. His report 

included an outcrop map of the coals in the Warrior basin and a general 

stratigraphic column. Culbertson Q), in 1964, described the geology of the 

coalbeds and estimated remaining reserves for all three major Alabama coalfields. More recent studies deal with petrology, stratigraphy, and paleogeography of the Black Warrior basin (3, 8-g, - 21) and the methane gas 

content of Alabama coalbeds (6). - 

REGIONAL STRUCTURE 

The Black Warrior coal basin lies within the Cumberland Plateau section 

of the Appalachian Highlands in north-central Alabama. The Mary Lee Group 

outcrops along the northern and eastern edge of the basin. The eastern margin 

of the study area is bounded by the Opossum Valley thrust fault (19) along 

most of its length. The coalbeds plunge into the basin dipping asmuch as 9' 

(fig. 3). The basin has a regional southwestern dip of lo to 2' and is 

covered by the Cretaceous onlap to the west and south. 

Black Warrior Coal Basin Structure 

The major structural feature within the Black Warrior coal basin is the 

Sequatchie anticline trending northeast to southwest through the center of the 

study area. The Warrior syncline lies to the west of the Sequatchie anticline 

and the Coalburg syncline lies to the east. Faulting is widespread in the 

Warrior basin with high-angle faults predominating and fault grabens common. 
FIGURE 3. - Structure mop drawn on the base of the Mary Lee coolbed. 
The strike of the known 

normal faults and fault segments have been plotted on a 

rose diagram (fig, 4) , The 

faults strike generally to 

the north-northwest , with 

two peaks on the rose diagram, N 08" W and N 24" W, 

indicating the dominant 

average strikes. Several 

lineaments detected with the 

use of remote sensing 

(LANDSAT-1) seem to coincide 

with certain known highangle faults (7). The 

presence and length of these 

fault-paralleling lineaments 

indicate the existence of 

previously unrecorded faults 

and longer known faults than 

those previously mapped, 

The faults tend to 

cluster in the two synclines, 

especially in the Coalburg 

syncline, with essentially 

12 8 4 0 90 readings plotted faults cutting the 

Sequatchie anticline, 

FIGURE 4, - Strike of normal faults in the Black Warrior se&es attributes the 

coal basin, faulting in the Coalburg 

syncline to a combination 

of lateral pressures from 

the Sequatchie folding, on the west, and the Opossum Valley thrust, on the 

east . 

The presence of faults can severely affect underground coal mining operations as well as surface mining. The faults in the Warrior basin range up to 

6 miles in length. The maximum vertical displacement reported by Sernrnes (19) - is about 200 feet; however, displacement of more than 100 feet is rare. A 

first alternative is to encounter these faults underground which necessitates 

mining along the fault until the vertical displacement is so small as to permit conventional mining machinery to continue into coal on the other side of 

the fault. A second alternative is to tunnel through the faults and resume 

normal mining operations when the coalbed is located on the other side, 

Either alternative results in a loss in production and can cause disruptive 

changes in basic mine development projections. Geologic studies of proposed 

mining sites utilizing standard surface mapping and well-planned exploratory 

core hole drilling to provide structural, as well as coal thickness and coal 

quality data, can help locate faults and delineate their direction of strike, 

dip, and vertical displacement. More efficient mine development plans can be 

devised to deal with the faulting when these basic geological data are used 

before selecting shaft sites and beginning full-scale mine development. 
Cleat and Inclined Fractures in the Mary Lee Coalbed 

Cleat surveys were made in seven underground mines operating in the Mary 

Lee coalbed. Approximately 250 strike measurements were taken on cleats 

(vertical fractures) and a similar number of additional readings were taken 

where inclined fractures (fractures inclined at about 45" to bedding) were 

also present. 

The five mines surveyed in the shallow, northern part of the study area 

have relatively well-defined, singular face cleat orientations (fig. 5), with 

few inclined fractures. Measurements taken in the Bessie mine indicate a 

bimodal face cleat. The face cleat orientations range from N 53" E to N 68" E 

in the north and are generally parallel to the axes of the folds. The butt 

cleat in the Mary Lee No. 1 mine is bimodal with the two peaks separated by 

10". The Segco No. 1 mine, in the same vicinity, has a wide, weakly trimodal 

butt cleat. The Chetopa and Bessie mines in the northeastern corner of the 

study area have well-defined, singular butt cleats. Butt cleat measurements 

in the Flat Top mine are quite variable, probably the result of difficulties 

in accurately measuring cleats where rib spalling has occurred. The butt 

cleats in the north of the study area varied in orientation from N 20" W to 

N 37" W, roughly parallel to the strike of the normal faults nearby, which 

have average strikes of N 08" W and N 24" W (fig. 5). 

Fracturing is quite varied in the two mines located in the deeper, 

southern part of the basin and also nearer to the structural front than any 

of the other mines (figs. 6 and 7). Both cleat and inclined fractures are 

present. In the Oak Grove and Blue Creek mines, the inclined fractures, 

which dip at approximately 45" to the coalbed, are much more predominant than 

the vertical cleat systems. The Oak Grove mine has a well-defined face cleat 

peak at N 64" E which is within the range found in the northern part of the 

area (fig. 69. Several peaks are present in the butt cleat direction with 

two (N 18" W and N 41" W) being the most dominant. 

The cleat directions measured in the Blue Creek mine are complex 

(fig. 62) with significant differences from the adjacent Oak Grove mine and 

the mines further to the north. Most cleats in the Blue Creek mine have 

strikes to the northwest, whereas in the other mines, the strikes are toward 

the northeast. Three peaks of similar dominance (N 48" W, N 13" W, and 

N 02" W) are present in the northwestern quadrant. 

The rose diagram (fig. 6s) of the strike of inclined fractures in the 

Oak Grove mine has several well-defined peaks. The most dominant peak is 

N 26" W. No preferred orientation is present for the dip of these fractures, 

with approximately half dipping east to northeast and half dipping west to 

southwest. 

Strikes of inclined fractures in the Blue Creek mine (fig. 6D) are more 

varied than those of the Oak Grove mine. The most dominant peak is N 07" W 

as compared with Oak rove's N 26" W most dominant peak. 
FIGURE 5. - Rose diagrams of cleat strikes in seven mines operating in the hlary Lee coalbed. 
250 readings 0 8 16 24 

318 readings 0 8 16 24 

240 readings 0 

6 

250 readings 0 

D 

FIGURE 6. - Rose diagrams of strikes of cleat and inclined fractures in the Oak Grove and 
i-l ,/ TUSCALOOSA COUNTY ). 1. 

/ ' 1- -L.', 

/ i 

LEGEND 

1 Calun~et .! Calu~~et 

: Howell 

; Bankhead 

s Ra~lway Fuel 

u Segco No. 1 

7St1lh 

h!ary Lee No. 1 

!lNATCO 

lo Acrowe Russell 

I1 Indian Head 

I.! lndlan Head 

1: lnd~an Head 

I; Excelsior 

1.5 Sulfur Springs 

11; Ruby 

I7 Barney 

1,s Riverslde 

1:) Pratt Fuel 

20 Sol~~erset 

21 Benoit 

:No. 10 

2; NO. 11 

-'I No. 8 

-*.; Red Star 

..f; T. N. Dav~s 

3 Hall -,,, Ada~r 

...,I Price 

:a ?iediiiont 

:1 Burliwell 

: Burnwell 

:: Yerkwood 

:: Kershaw 

::; Gall111 2 

,r, Colla 

.:; VIegra 

;s Praco 

:o Powahatan No. 2 

;o Powahatan 

.;I Labuco 

;: Porter. 

.;: Palos 

; ; bess~e 

;:; Flat Top 

;!; Ba~iiier 

;; Chelope 

;A Sayre 

;!I New Castle Nos. 2, 5, 5 so hlary Lee No. 1 

.;I Graves 

..;-, Sayreton 

.+: Hail~ilton 

.;: 3ak Grove 

:;.; Blue Creek 

FIGURE 7. - Mines in the Mary Leecoalbed. 
The Pottsville Formation is divided into two 

units based on the presence 

of productive coalbeds. The 

Upper Pottsville contains 

all of the thick, economically important coalbeds. 

These coalbeds have been 

FIGURE 8. - Generalized stratigraphic column showing divided into six groups 

the Mary Lee Group coalbeds and adia- which, in descending order, 

cent strata. are the Brookwood, Gwin, 

Cobb, Pratt, Mary Lee, and 

Black Creek Groups w. The Lower Pottsville contains no known thick, productive coalbeds and is predominantly a barren interval which begins at the 

base of the Black Creek Group. 

The Mary Lee Group is comprised of five coalbeds which, in descending 

order, are the New Castle, Mary Lee, Blue Creek, Jagger, and Ream (fig. 8). 

The intervening strata are shales and sandstones with thin fireclays underlying the coalbeds in many areas. The stratigraphic section tends to thicken 

to the south and southwest. 
New Castle Coal 

The New Castle is a discontinuous coalbed that ranges from 0 to 4 feet 

in thickness. It attains maximum thickness in Tuscaloosa County, where, in 

places, it is comprised of three benches, spread through up to 35 feet of 

vertical section. Normally a single bench does not exceed 2 feet in thickness. 

In Walker and Jefferson Counties, the New Castle ranges from 0 to 1 foot, with 

the exception of a small area within the Coalburg syncline where it attains a 

maximum thickness of 3 feet (fig. 9). McCalley (14) indicated that west of 

Palos, the New Castle is seldom over 12 inches thick with the exception of a 

small area near Carbon Hill. The New Castle coal is absent in large areas of 

Jefferson and Walker Counties but is present throughout the area under investigation in Tuscaloosa County and attains a maximum thickness of 4 feet. 

The New Castle coal, where present, occurs between 15 to 65 feet above 

the Mary Lee (fig. 10). The interval thicknesses within the hatchured areas, 

where the New Castle coal is absent, are approximate and based on trends in 

thickness and continuity of intervening lithologies. The sandstones in this 

interval range from 0 to 53 feet in thickness. There is a general correlation 

between interval thickness and sandstone thickness (fig. 11). 

From analysis of core log and mine data it appears that in the vicinity 

of New Castle the Mary Lee coalbed may have been mistakenly called the New 

Castle. Data indicate that the New Castle coalbed is absent at New Castle and 

first appears to the south near Lewisburg, Ala. (figs. 1, 12, and 13). 

Mine sections as described by Butts (9 were used for the construction 

of cross section E - E ' (figs. 12 and 14). Measured mine sections from the 

New Castle Nos. 2 and 6, Mary Lee No. 1, and Hamilton mines located north to 

south, respectively, appear to be correlative. The nomenclature problem has 

arisen since the coal in the New Castle No. 6 mine is named New Castle, 

whereas in the adjoining mines to the south the same coalbed is named Mary Lee. 

Mary Lee Coal 

The Mary Lee coalbed is comprised basically of two benches (figs. 12, 15, 

and 16) which coalesce in the northern part of the Warrior syncline. In certain localities, the Mary Lee is split into as many as five benches. On the 

basis of core log data, this coal is present throughout the entire study area, 

unlike the New Castle and Blue Creek coalbeds. The Mary Lee coalbed ranges in 

thickness from 2 to 12 feet and is normally 2 to 6 feet thick in the northwestern half of the basin and from 6 to 8 feet in the southwest. The combined 

thickness of all benches and intervening stringers of coal were included in 

the construction of the Mary Lee coal isopach (fig. 17). This map should not 

be construed as an interpretation of minable coal thickness, because in most 

areas of the Warrior field only one bench of the Mary Lee is mined. 
FIGURE 9. - New Castle coal isopach. 
FIGURE 10. - New Castle-Mary Lee interval isopach. 
FIGURE 11. - lsopach of sandstone in the New Castle-h4~ry Lee interval. 
FIGURE 12. - Map showing location of regional cross section lines. 
Northeast 

D 

LEGEND 

fT""1 Sandstone 1 Shale 

Coal 

FIGURE 13. - 
Northeast Southwest 

1 L~ew Castle No. 6 L~ary Lee No. I 

New Castle No. 2 Hamil ton 

LEGEND 

0 Shale 

Coa l 

- 0 8 16 

Horizontal scale, lo3 ft 

FIGURE 14, - Cross section E - E , 
North 

New Castle 

Mary Lee 

Blue Creek 

LEGEND 

Sandstone 

0 Shale 

Coal 

FIGURE 15. 
New Castle 

Mary Lee 

Blue Creek 

orth 

B 

r 

LEGEND 

,-:::I Sandstone 

[-I Shale 

Coal 

Hori

FIGURE 16. - Cross section B - B . 
FIGURE 17. - Mary Lee cm l isopach. 
Two benches of the Mary Lee are present over much of the basin and are 

separated by a parting which ranges to a maximum of 10 feet in Jefferson 

County near Oak Grove, Ala. The top bench of coal is usually 0 to 24 inches 

in thickness, whereas the bottom bench is normally between 30 and 90 inches 

thick. 

There is a general correlation between the Mary Lee coalbed thickness 

and the thickness of sandstone in the New Castle-Mary Lee interval (fig. 11). 

There is an excellent correlation between the thickness of the Mary Lee coalbed and the thickness of the New Castle-Mary Lee interval (figs. 10 and 17). 

In the study area, the Mary Lee coal ranges from high-volatile in parts 

of Walker County, through medium-volatile to low-volatile coal in northeastern 

Tuscaloosa and southwestern Jefferson Counties (fig. 18). The Pratt coalbed 

also exhibits a similar increase in rank to the southeast, across the Warrior 

coalfield (2). This rank variation can be attributed to the degree of 

tectonism cGmbined with depth of burial of the coalbeds. 

Blue Creek Coal 

The Blue Creek coal, where present, occurs from 7 to 40 feet below the 

Mary Lee and typically lies 10 to 25 feet beneath it. This coalbed reaches 

a maximum thickness of 5 feet, but is normally between 1 and 2 feet thick 

(fig. 19). The Blue Creek coal, absent over much of Tuscaloosa County, is 

oriented in a wide belt trending northwest-southeast and exhibits minor 

increases in thickness in the synclines. 

Most regional maps inthis report were constructed by using data from more 

than 700 core logs. The isopach of the Blue Creek coalbed was based on approximately 200 core logs because of the general practice of terminating coring a 

short distance below the lower bench of the Mary Lee coalbed, which is the bed 

of primary importance in mining. 

Correlations of the Mary Lee and Blue Creek coalbeds have generally been 

based upon limited data. The limited access to all pertinent data, the 

geologic complexities due to the close stratigraphic proximity of the two 

coalbeds, and the splitting of the Mary Lee into two or more benches has made 

correlation difficult. The investigators in this study have had the distinct 

advantage of access to data obtained in exploratory core hole drilling by most 

of the coal mining Companies in the Warrior field. Correlations presented 

here were derived from the construction of several cross sections and panel 

diagrams of individual mine properties, which were subsequently linked 

together for regional studies. Representative general cross sections 

(figs. 12, 13, 15, 16, and 20) are presented to illustrate regional stratigraphic trends. 

The lower bench of the Mary Lee coalbed is now being mined in the newer 

deep mines in the southern part of the basin. This bench, commonly called 

the "~lue Creek1' in the south can be traced northward through core logs to 

where it coalesces with the top bench of the tlary Lee. The correlations can 

further be traced to outcrops in Walker and northwestern Jefferson Counties 
TUSCALOOSA 3 

G- - - - - COUNTY i 

LEGEND 

v74 High volatile 

Scale, ft 

Medium volatile Low volatile 

FIGURE 18. - Map of volatile content of the Macy Lee coalbed. 
i. BLOUNT 

\ 

WALKER COUNTY 

. -r' JEFFERSON 

COUNTY 

/ 

3 

LEGEND 

Contour interval, 

I ft 

Scale, ft 

,ey map 

COUNTY _L -- 

FIGURE 19. - Blue Creek cool isopoch. 
Northeast 

P 

New Castle 

Mary Lee 

LEGEND 

KI Sandstone 

1-1 Shale 

Coal 

Horizon

FIGURE 20. - Cross section C - C . 
where the coalbeds were originally distinguished by McCalley (14). Two cross 

sections (figs. 15 and 16) show the sporadic occurrence of the actual Blue 

Creek coalbed beneath the Mary Lee. 

Nomenclature and correlation problems are in part due to the fact that 

the Mary Lee coal changes rank in the basin. In the northern part of the 

field, where most of the mining has occurred, the Mary Lee is known as a highto medium-volatile coal. To the south, where newer mines have been opened, 

the Mary Lee is a higher rank, low-volatile coal (fig. 18). In Tuscaloosa and 

southern Jefferson Counties this coal is called the "~lue Creek," although 

stratigraphically it is the lower bench of the Mary Lee. 

Jagger and Ream Coals 

Data on the Jagger and.Ream coals are insufficient to construct regional 

coal isopach maps. Only a very small number of core holes have been drilled 

deep enough below the Blue Creek to intercept either coal. The few data show 

the Jagger and Ream coalbeds to be often absent, thin, and erratic in occurrence, and to vary greatly in depth beneath the Blue Creek. 

Depositional Setting of the Mary Lee Group 

The American coalbed is the lowermost productive member of the Pratt 

Group of coalbeds and overlies the Mary Lee Group by 350 to 750 feet in the 

study area. An isopach (fig. 21) of the interval between the Mary Lee and 

American coalbeds shows a southward thickening wedge of sediments which 

suggests a primary source of detrital material generally to the south. A 

map of sandstone distribution between the Mary Lee and the overlying New 

Castle coalbed (fig. 11) shows the largest concentration of sandstone in the 

south and southwest portion of the area. This again indicates a south or 

southwest source area. Previous investigations of sediment source directions 

into the southern portions of the Black Warrior basin have shown results 

similar to those indicated on figures 20 and 21. Ehrlich @) found that the 

quartz content of low rank graywackes in the basin diminishes to the south 

indicating proximity to the original sediment source. Ferm (9) observed that 

all Pennsylvanian intervals, including the coal groups, expand southward. 

Davis and Ehrlich (3) found that mineral compositional trends in late 

Carboniferous sediments of the Black Warrior basin show variation along 

roughly north to south trends and that no compositional trends have been 

detected at high angles to present Appalachian trends. This was interpreted 

by Davis and Ehrlich to have been a manifestation of tectonic activity along 

the Ouachita structural belt to the south. The Ouachita structural belt 

defines the southern boundary of the Warrior basin (11, 2) and was probably 

the ultimate source of Pennsylvanian clas tic sediments which were brought into 

the basin. Within the study area, the local source area was to the southwest 

and sands were transported primarily to the north and northeast. 

An isopach map of the New Castle-Mary Lee interval (fig. 10) shows the 

relatively thick sedimentary section to the northeast separated to the west 

and south by low interval thicknesses (less than 20 feet); the sediment 

present in the northeast may have been derived from a second source area to 
v7A 400 - 500 

500 - 600 

600 - 700 

Greater than 700 

Scale, ft 

FIGURE 21. - American-Mary Lee interval isopach. 
to the north or northeast. Mary Lee Group coal thickness (combined isopachs 

of the New Castle, Mary Lee, and Blue Creek coalbeds) distribution (fig. 22) 

indicates that thick areas of coal in the northeast are more or less separate 

from the coals farther to the south and west. This suggests contemporaneous 

peat deposition within two separate locations as in two distinct deltaic 

complexes--one developing to the northeast and the other to the southwest. 

Thomas (20) - found evidence for these two different source directions in late 

~ississi~ian and Pennsylvanian sandstones northeast of the study area. 

Hobday (g) studying Pennsylvanian-Pottsville sandstone cross-bed directions 

found evidence of two sedimentary systems which merged near Cullman County, 

just north of the study area. 

Individual coalbeds within the Mary Lee Group show thickness distributions that suggest original peat accumulation in fluvial-deltaic and lowlying coastal plain environments. The New Castle coalbed (fig. 9) represents 

peat deposition associated with an ancient deltaic complex. The northward 

thinning wedge of sediment on which the New Castle coal lies (fig. 10) 

indicates that delta progradation was primarily from the southwest, although 

small sediment contributions are thought to have been brought in from the 

northeast. Areas of thicker coals (over 2 feet) were probably locations of 

peat swamps between major distributary channels that flowed to the north and 

northeast filling the basin. Once the delta had been cut off from its source 

of detrital matter, peat could accumulate over most of the delta platform 

forming extensive, relatively thin coal deposits. 

The Mary Lee coalbed (fig. 17) is representative of peat deposition 

within an ancient low-lying fluvial system. Thicker Mary Lee coal bodies 

(over 6 feet) form sinuous patterns trending generally northeast-southwest. 

These thick coal bodies probably represent locations of ancient low-lying 

inland valleys that were associated with the major stream courses in the upper 

delta plain. 

The Blue Creek coalbed is distributed as wide belt-shaped bodies 

(fig. 19). Trends of thicker coal (over 2 feet) parallel these wide belts 

in the eastern and southeastern portions of the area. To the northwest, 

however, thick Blue Creek coal bodies are elongated at right angles to the 

wider coal belts. The Blue Creek coal appears to represent peat accumulation 

along coastal plains and perhaps, within shallow lagoonal lows behind ancient 

beach barriers. The beltlike distribution of the Blue Creek coal suggests a 

general parallelism to such an ancient coastline. The change in trend directions of thick coals indicate at least two different environments associated 

with peat accumulation: (1) Peat accumulation parallel to the larger belts 

probably represents abandoned deltaic distributary channel environments 

associated with delta progradation from the south and southeast and 

(2) coastal processes become more pronounced farther to the north and northwest and resulted in channel development perpendicular to the strand line. 

Small tidal channels which drain lagoonal areas are good examples of such 

features. With a drop in sea level these channels were abandoned and became 

locations of thick peat accumulations. 
\ 

k, Jasper 

? * 

WALKER COUNTY 

I 

k-.t s- BLOUNT 

COUNTY 1 

FIGURE 22. - Combined isopach of the Mary Lee Group of coalbeds. 
STRUCTURAL CONTROL OF MARY LEE GROUP SEDIMENTATION 

There is a good correlation between interval thicknesses, Mary Lee Group 

coal thickness distribution, and structure. Comparison of the New Castle-Mary 

Lee interval isopach (fig. 10) with thickness distribution of the Mary Lee 

Group of coalbeds (fig. 22) shows an excellent correlation between thick 

sediments (greater than 40 feet) and thick coal (greater than 6 feet). In 

addition, the structure map (fig. 3) shows that these areas of thick sediments and thick coal tend to correspond with either structurally low or 

highly faulted portions of the basin. Examination of isopachs of individual 

coalbeds within the Mary Lee Group of coals indicates varying degrees of 

structural control over coalbed distribution. 

New Castle Coal 

An isopach of the uppermost coalbed, the New Castle, is shown on figure 9. This coalbed is altogether absent in the vicinity of the Sequatchie 

anticline but is present within the Coalburg and Warrior synclines. Thicker 

New Castle coal also predominates in the structurally deep southwestern part 

of the area. A concentration of thick New Castle coal in the northeast is 

associated with an excessively faulted region west of Birmingham. The close 

association of structure with New Castle coal thickness suggests that ancient 

physiographic low-lying areas of peat accumulation correspond to synclinal 

features present at the time of original deposition. Some of the faulted 

zones on the structure map (fig. 3) may have been subsiding areas at the time 

of coal deposition and thus were loci for thicker than "normal" peat accumulation. Because these normal faults are nearly perpendicular to major sediment 

source directions (northeast and southwest), they may be growth or slump 

features similar to those in the Cretaceous sediments of the Gulf Coast. 

Apparently deposition was structurally controlled before time of New Castle 

deposition because similar relationships are seen in the New Castle-Mary Lee 

interval isopach (fig. 10) . 

Mary Lee Coal 

An isopach of the Mary Lee coalbed (fig. 17) shows that most of the coal 

more than 4 feet thick occurs within the general area of the Coalburg syncline 

and also within structurally deep areas to the southwest. As with the New 

Castle, thick Mary Lee coal is associated with the faulted region in the 

northeast. The most notable difference between the New Castle and Mary Lee 

coal isopachs is that a significant thickness of Mary Lee coal is present 

along the Sequatchie anticline whereas the New Castle coal is absent. 

Like the New Castle, the Mary Lee coalbed isopach indicates peat 

accumulation was affected by the structural configuration of the area at 

the time of deposition. Thick and extensive coal within the general confines 

of the present Coalburg syncline suggests that this structural feature was the 

location of extensive physiographic lows where peat could accumulate. The 

present day Sequatchie anticline apparently was a minor feature during the 

time of Mary Lee coal deposition and, therefore, did not influence peat 

accumulation. Consistent and abrupt changes in coal thickness just north 
and west of the present Sequatchie anticlinal axis indicate the position of 

an ancient "hingle line" oriented northeast-southwest that separated the 

deep southeastern basin from shallower northwestern areas. The area of Mary 

Lee coal over 4 feet thick northwest of the hingle line cannot be correlated 

with the present-day Warrior syncline, but there is a good correlation of 

thick coal with a faulted region immediately to the north of the syncline. 

Cross sections taken north to south across the basin show that the Mary 

Lee coal is thicker within areas of (greater) structural deepening. These 

sections, shown in figures 12, 15, and 16, indicate that thicker Mary Lee coal 

in the southern portions of the area is a result of a gradual southerly 

increase in thenumber and thickness of individual coal benches. Although up 

to five separate benches have been recognized on some core log descriptions, 

two major benches can be readily traced throughout the southern portion of the 

field. To the north these two benches coalesce to form a single minable unit. 

Intermittent and relatively rapid subsidence of the southern area, accompanied 

by influx of detrital material, is recorded by the numerous splits in the 

Mary Lee. An increasing number of coal benches to the south indicates more 

frequent periods of subsidence in this direction. The stability of the 

northern areas accounts for relatively thin coal and few or no shale partings. 

Blue Creek Coal 

Data used to construct the isopach of the Blue Creek coalbed (fig. 19) 

were limited and there is little correlation of coal thickness with present 

structural configuration (fig. 3). The distribution of the Blue Creek coal 

suggests only a subtle influence of structure on original peat deposition. 

Differences in trend directions of thick Blue Creek coals suggest at least 

two different modes of original peat accumulation which were ultimately controlled by differential structural movements between the more actively subsiding Coalburg syncline and the more stable area to the northwest. 

GEOLOGIC FACTORS INFLUENCING MINING OPERATIONS 

Roof instability and methane emissions are two major problems which 

affect underground coal mining operations in the Warrior basin. Comprehensive geological investigations can be used by mine operations to anticipate 

areas of possible roof problems. Desorption tests of coal samples from 

vertical boreholes can be used to estimate the methane content of virgin 

bituminous coalbeds. This information can then be applied to design mine 

ventilation systems and to determine whether degasification of the coalbed 

in advance of mining will be necessary. 

Strata Overlying the Mary Lee Coalbed 

The rock directly overlying the Mary Lee coalbed throughout most of the 

Warrior field is shale (figs. 13, 15, 16, 'and 20). There is an overall 

increase in the frequency and size of sand bodies in the southern parts of 

the basin (fig. 11). In Tuscaloosa County, where sandstone directly overlies 

the Mary Lee, there has been very little erosion of the top bench of coal. 

There are no known cases where the Mary Lee coal has been reported to be 

absent due to erosion and subsequent filling by channel sands. 
Roof problems may be encountered during mining of the lower bench of the 

Mary Lee where only a thin parting may separate it from the upper bench, which 

is often left in place. Roof bolts should be long enough to penetrate the 

parting, upper bench and to firmly anchor into competent overlying strata. 

ROO£ problems may also be encountered in areas where the interval to the New 

Castle coalbed is smallest. The interval with the next higher coalbed 

(fig. 10) is critical because the uppermost plane along which the roof tends 

to separate is the bottom of the coalbed immediately above (15). Other areas 

of unstable roof may be related to sandstone channel depositywhere differential compaction has occurred along the margins of sandstone channels. 

Methane Gas Content and Degasification 

Coal production in the Warrior basin has in the past (fig. 7) been from 

relatively shallow (less than 1,000 feet) depths in older mines where methane 

emissions were not a serious problem. New mines are now operating at depths 

exceeding 1,000 feet and there are mines planned for depths approaching 

2,000 feet. The newer deep mines are already encountering problems with 

methane emissions. Desorption tests of coal cores indicate that at these 

greater depths, .the problem of methane gas affecting mining operations will 

be acute. One sample obtained at a depth of 2,200 feet yielded 17 crn3lg or 

544 ft3/ton of coal in place (13, 3. The methane emission from a mine in 

cubic feet per ton of coal mina would be much greater than the calculated 

cubic feet of methane per ton of coal in place because gas is also emitted 

from the coal in the face, ribs, roof, floor, pillars, old workings, and gob 

areas (l2). 

Coal samples were obtained from seven core holes ranging in depths from 

600 to 2,200 feet. A graph (fig. 23) for estimation of gas content was construtted by plotting the 

20- 

18 

16 

14 \ 0 

10 5 12- 

vi 

10- 

J 

2 

e 

6 

1~~1~~ measured gas content versus 

- - depth for each sample. The 

methane gas content of the 

- - Mary Lee Group, within the 

study area, has been - - estimated to be more than 

1 trillion ft3 (5). Nearly - 70 pct of this gas is con- 

- tained within the Mary Lee 

coalbed alone and could be 

8- - encountered by mining 

operations. - - 

The relationship of gas 

4- - content to depth, as shown 

on the graph (fig. 23), can 

2- / ,0' 

- 

be used to delineate geoCIC-Cl > -- lit 1111 1111 1111 graphic areas of high gas 

0 500 1,000 1,500 2,000 2,500 concentrations. TheMary 

OVERBURDEN, ft Lee coals aremore than 1,500 

feet deep in only 12 pct of 

FIGURE 23, - Depth of coolbed versus gos content, the study area (fig. 24), 
FIGURE 24. - Overburden isopach of strata overlying the hiary Leecoalbed. 
yet more than half of the methane is estimated to be in these deep coals. 

The average methane content and the calculated methane resources of each 

overburden interval is given in table 1. 

TABLE 1. - Methane resources 

Due to the lack of data, the gas content of the Mary Lee Group in the 

deeper part of the Warrior basin, outside of the study area (fig. 2),could not 

be calculated, but it should be noted that in the deeper part of the Warrior 

basin it is enormous. Every additional square mile of coal 6 feet thick, at a 

depth of 2,000 feet, could contribute 3.3 billion ft3 of gas to the 1 trillion 

cubic foot total. 

Methods to remove methane in advance of mining are being tested in the 

Mary Lee coalbed. The Bureau of Mines is currently involved in a cooperative 

venture in the Warrior basin to test the feasibility of degasification of the 

Mary Lee coalbed from vertical boreholes in advance of mining. 

Methane resources (ft3), 

Mary Lee Group 

0.13 x 1011 

1.15 x lo1' 

3.76 x 10l1 

3.54 x 1011 

1.96 x 1011 

10.54 x lo11 

Overburden (ft) 

0-500.. . . . . . 500-1,000. . . . 1,000-1,500.. . . . . 1,500-2,000 ....... 2,000-2,500. .... .. Total . . . . . . . . . .; 

SURFACE JOINT AND CLEAT MEAS UREMENTS 

As part of the structural interpretation of the study area, joint and 

cleat strikes were measured in outcrops. The primary purpose was to obtain 

data for evaluation of a cleat-prediction technique which was successfully 

applied in the northern Appalachian coalfields (4-3). Cleat directions are 

important because they influence the flow of methane in coalbeds. It has been 

demonstrated in degasification experiments in coalbeds with high permeability, 

conducted underground by the Bureau of Mines, that horizontal holes drilled 

perpendicular to and, therefore, intersecting the largest number of face 

cleats will yield 2.5 to 10 times the amount of gas as holes drilled perpendicular to the butt cleat. 

Av methane 

content 

The directional permeability is, in turn, important in the placement of 

vertical and slant degasification holes drilled from the surface into a coalbed. A vertical hole in a coalbed with a well developed cleat system will 

collect gas at a higher rate from the face cleat direction than from the butt 

cleat direction. An elliptical drainage pattern will be developed with the 

long axis parallel to the face cleat. When drilling slant holes from the 

surface to intersect coalbeds horizontally, it is important that the hole 

penetrates the face cleats as nearly perpendicular as possible for maximum 

gas flow. To determine the most efficient pattern for vertical degasification 

holes and orientation for slant holes in virgin coal, it is requisite that the 

cleat orientation be determined. 

cm3/g 

0.25 

2.00 

7.50 

13.10 

18.60 - 

~t~/ton 

7.5 

64.0 

240.0 

419.0 

595.2 - 
154 

Samantha SE 

153 

Searles SW 

Coltondale 

Number of 

readings 

Surface jo~nts 

Quadrangle 

name 

,........... L~mitof detailed 

geologic mapping 

FIGURE 25. - Rose diagrams of surface ioints for 35 quadrangles. 
Butt cleat N Field Methods and Data 

Compilation 

3 

Surface joints were 

Face cleat measured in 35 quadrangles 

in and around the primary 

study area (fig. 25). Whenever possible, 15 readings 

were taken at 10 separate 

locations within the quadrangles. Locations were 

W spaced as evenly as the out77total readings 0 10 crops would permit. Fewer 

readings were obtained along 

Scale of readings the eastern margin of the 

area, mainly because of the 

FIGURE 26. - Composite rose diagram of principal surface increasing structural comcleat trends. plexity of the outcrops and 

because portions of the 

quadrangles are outside of 

the Warrior basin study area. Individual readings were taken on joints of 

varying prominence and in various lithologies and bed thicknesses to obtain 

an unbiased representation of the principal joint strikes. 

When coal outcrops or strip mines were present, data were also obtained 

on surface cleat strikes (fig. 26). Fifteen readings from three locations 

were about the average number of surface cleat measurements taken per quadrangle. The uniformity of the generally orthogonal cleat system found in 

coalbeds permits the measurement of fewer readings to establish directional 

trends. 

The principal surface 

joint trends of each quadrangle in figure 25 were 

determined as described by 

Diamond (4-2) and are tabulated in appendix A. The 

principal surface cleat 

trends were also determined 

and are tabulated in appendix B. The principal surface joint and surface cleat 

trends from each quadrangle 

were plotted on composite 

194 total readings 0 10 rose diagrams for regional 

I evaluation (figs. 26 and 27). Scale of read~ngs 

Prediction of Subsurface 

FIGURE 27. - Composite rose diagram of principal surface Cleat Orientations 

joint trends. The composite rose 

diagram of principal surface 
N joint strikes (fig. 27) 

Butt cleat indicates numerous trends, 

especially in the west. 

For cleat prediction, 

individual peaks are 

Face cleat assigned orders of dominance based on the 

number of readings corn-. 

prising the peak. The 

most dominant peak is 

assigned the first order 

of dominance; the next 

most dominant is the 

26totaI readings 0 - 5 second order, etc. The 

peaks in the west are 

Scale of readings ;hen paired with those 

in the east (table 2) 

FIGURE 28. - Composite rose diagram of principal under- to determine the possible 

fundamental joint systems ground cleat trends. (joint sets oriented perpendicular to each other). 

TABLE 2. - Fundamental regional systems from directional data 

Data source I Sys tem I Degrees 

Surface joints.. . . . . 

NOTE.--Superscripts indicate the order of dominance within the 

Surface cleat ....... 

directional group (east or west) for surface joints and 

i (1) N 65" WI I -*N 40" E1 

(2) *N 81" WI-N 07" Els' 

(3) N 20" WI ' -*N 59" El 

(4) N 32" WV -*N 59" El 

(5) N 42" WI -9;N 59" E' 

an asterisk denotes the dominant trend of each system. 

separation 

105 

88 

79 

91 

101 

(1) N 21" w-;~N 61" E 

{(2) N 36"W-;kN 61" E 

It was found in an investigation of the Pittsburgh coalbed in southwestern Pennsylvania and northern West Virgini.a (4-5) - - that a joint system 

composed of the most dominant set when combined with a perpendicular set of 

82 

97 

the first or second order of dominancewill usually give the best estimation 

of cleat orientation. The most dominant set of the selected system is 

ordinarily the face cleat direction. These estimation criteria were formulated by comparing the surface joint data to cleat data obtained in underground mines in the same area. 
A composite rose diagram (fig. 28) of the principal underground cleat 

strikes measured in the Mary Lee coalbed was constructed to serve as a 

standard against which the surface joint data could be evaluated. This 

diagram indicates two possible fundamental systems as follows: N 24" W- N 60" 

E = 84" separation, and N 37" W-N 60" E = 97" separation. (table 2). Both 

systems contain the N 60' E face cleat trend and neither system seems to be 

dominant over the other. The two separate butt cleat trends present do not 

appear to be segregated within any particular geographic or structurally 

defined area. In fact, the Chetopa nine (fig. 5) has a bimodal butt cleat 

with trends of N 27" W and N 37" W, which are nearly identical to the average 

butt cleat orientations on the regional composite (fig. 26). The presence of 

a bimodal butt cleat, both in the Chetopa mine and on the composite diagram is 

probably the result of an "overlapping" of dominant trends as described by 

Nickelsen and Hough (18). - 

Of the five fundamental joint sys tems in table 2, only one (N 65" W' ' - N 43" E' = 105" separation) satisfies the established estimation criteria. 

The dominant set of this system (N 40" E'), while not being the closest 

surface joint set to the underground face cleat is only 20" from the N 60" E 

actual face cleat orientation (fig. 28, table 2). The N 65" W" set diverges 

30" to 40° from the bimodal butt cleat trends. The 20" divergence of the 

estimated value of the face cleat from the actual value is not considered to 

be of such a magnitude to severely affect planning of well-density patterns or 

orienting slant hole drilling paths. 

The N 59" E' surface joint peak is essentially the same as the N 60" E 

face cleat orientation observed in the underground mines (fig. 28). However, 

the three western joint sets that this peak could be paired with to form 

potential fundamental systems (Nos. 3, 4, and 5, table 2) are of very low 

dominance. Hence no sys tem containing the N 59" E' joint set would meet the 

established criteria and be selected as an estimator of the underground cleat 

orientation. Although the analysis of surface joints has provided an adequate 

estimate of underground cleat orientations on a regional basis in the Black 

Warrior coal basin, it is not always reliable for an individual mine property 

or single quadrangle size area. Similar studies on the Pittsburgh coalbed 

(4-5) - - determined that the small number of joint readings usually obtainable 

for a limited area does not provide sufficient data to clearly delineate 

individual trends. 

The geologic section above the Mary Lee Group contains numerous coalbeds. 

Many of these coalbeds outcrop in the study area and measurements on cleat 

strikes were obtained (fig. 5). The principal cleat directions from all the 

quadrangles were plotted on a single regional composite rose diagram (fig. 26). 

The composite diagram has a very pronounced face cleat peak at N 61" E, and a 

bimodal butt cleat peak at N 21" W and N 36" W. These peaks are essentially 

identical to the underground cleat orientation represented on figure 28 and 

in table 2. It is apparent that in areas where coalbeds outcrop at the 

surface, measurements and evaluation of their cleat orientations should 

provide the best estimate of the subsurface cleat orientation. Recent investigations in other coalbeds (17) have confirmed that cleat orientations remain 

parallel throughout a vertiGl section. 
Origin of Joints and Cleats 

The two fundamental surface joint systems (table 2) composed of the two 

dominant western sets (N 65" W" -N 40" El and N 81" W' -N 07" E') are quite 

similar to the two dominant surface joint systems (N 57" WI -N 27" E' ' and 

N 76O W' -N 15" E' ) measured in the Appalachian Plateau of Pennsylvania and 

West Virginia (4-5, l8). Nickelsen and Hough (18) relate the origin of the 

western component of the two fundamental joint systems in the north-central 

Appalachians to extensional forces related to the principal compressive stress 

which was ultimately responsible for the northeast-southwest folding in the 

area. It seems likely that a similar origin for the N 65" W' ' and N 81" W' 

joint sets in Alabama is possible. The eastern component of the joint systems 

would probably result from late, release-type fractures resulting from a 

combination of residual tectonlc stress differences during erosion and 

unloading. 

Several complications to the compressive stress origin theory are 

recognized. The most serious problem is that in the Warrior basin the 

N 65O W" and N 81" W' surface joint sets are about 20" to 36" off, respectively, from a perpendicular orientation with the structural axis. In the 

north-central Appalachians, however, the dominant surface joint sets to the 

northwest were more nearly perpendicular to the structural axis and parallel 

to their associated maximum compressive stress. Nickelsen and Hough believe 

that in their study area the principal joints formed early, before the folding 

and faulting, and along slightly varying stress axes. One possible explanation is that the compressive stress from the southeast that eventually led to 

the formation of the folds and faults in the Alabama area was shifted to a 

more east-southeast orientation during the formation of the joints. 

A second possible explanation for the orientation of the joints with 

respect to the maximum compressive stress axis of the folds is that they are 

associated shear fractures. The N 65" W" and N 81" W' joint sets are within 

the theoretical interval for shears associated with a compressive stress 

oriented at approximately N 45" W (perpendicular to the fold axes). The 

N 20" W" and N 7" WtV surface joint trends (fig. 27) could then be the 

conjugates of the N .65" W' ' and N 81" W' sets, respectively. A minor complication to both compressive stress-related joint origins is that there is 

no obvious tangential movement observed on the joint surfaces as would be 

expected. However, the joint surfaces in the north-central Appalachians, as 

described by Nickelsen and Hough as being of compressive origin, also were 

similarly lacking in evidence of tangential movement. 

A third possible explanation for the orientation of the dominant westerly 

surface joint sets is that they have a tensional origin as a result of either 

the warping of a sedimentary basin or the vertical growth of basement structures (18). No readily apparent, properly oriented downwarping or vertical 

growth is associated with the study area to produce the observed N 65" W' I and 

N 81" W' joint sets by tensional forces. 

The last major surface. joint set to consider on figure 27 is the N 59O E' 

trend. This set and the N 40" E' set are the most dominant joints to the east. 
The N 59O E' surface joint set is essentially parallel to the N 61" E composite surface face cleat (fig. 26) and the N 60" E composite underground' face 

cleat (fig. 28). The origin of all three fractures is probably related. An 

origin related to the Appalachian structural front is not readily apparent. A 

more likely source for the stresses which produced the N 59" E' surface joint 

is the Ouachita orogeny in the southwest. Depending on the actual orientation 

of the Ouachita structural front, the N 59" El surface joint and the face 

cleats could either be extensional fractures oriented parallel to the maximum 

compressive stress or they could be shear fractures. A tensional origin has 

been discounted. The maximum tensional stress related to the Warrior basin 

would be oriented perpendicular to the northeast-southwest axis of the 

depositonal basin. This tensional stress would probably not produce a fracture in the vicinity of N 60" E. 

SUMMARY 

The Mary Lee coalbed is the only coal of the Mary Lee Group that is persistent throughout the entire study area. It is split into as many as five 

benches and is comprised basically of two benches which have a combined 

thickness of 2 to 12 feet. The Mary Lee coalbed changes rank from a highvolatile coal, in parts of Walker County, through medium-volatile to lowvolatile coal in northeastern Tuscaloosa and southwestern Jefferson Counties. 

Faults in the Warrior coalfield strike north-northwest. Face cleats 

measured in mines operating in the Mary Lee coalbed are oriented generally 

parallel to the axes of folds. The butt cleats trend parallel to the strike 

of the faults. 

Sedimentation was subject to structural control. Areas of thick coal 

and sediment correspond to structurally low or highly faulted portions of the 

basin. Individual coalbeds within the Mary Lee Group show thickness distributions which indicate original peat accumulation in fluvial-deltaic and lowlying coastal plain environments. 

The methane gas resources of the Mary Lee Group coalbeds exceeds 1 trillion cubic feet in the area under investigation. Seventy percent of this gas 

is contained within the Mary Lee coalbed alone and, at depths exceeding 

1,000 feet, methane emissions will adversely affect mining operations. 

Subsurface cleat orientations can be accurately predicted on the basis of 

cleat directions measured at the surface. As structural complexity increases 

the variation in surface and subsurface cleat orientations also increases in 

complexity. On a local basis, proximity to structural fronts may mask 

regional cleat trends, but throughout a vertical section the cleat orientations remain parallel. Surface joint trends can only be used on a regional 

basis in the Warrior basin to determine the general orientation of cleats. 
REFERENCES 

1. Butts, C. Analyses of Alabama Coals. Geol. Survey of Ala., Bull. 31, 

1926, 117 pp. 

2. Culbertson, W. C. Geology and Coal Resources of the Coal-Bearing Rocks 

of Alabama. Geol. Survey of Ala., Bull. 1182-By 1964, 79 pp. 

3. Davis, M. W., and R. Ehrlich. Late Paleozoic Coastal Composition and 

Dynamics in the Southeastern U.S. Geol. Soc. America, Special 

Paper 148, 1974, pp. 171 -187. 

4. Diamond, W. P., C. M. McCulloch, and B. M. Bench. Estimation of Coal 

Cleat Orientation Using Surface-Joint and Photolinear Analysis. 

Geology, v. 3, No. 12, 1975, pp. 687-690. 

5 . . Use of Surface Joint and Photolinear Data for Prediction of 

Subsurface Coal Cleat Orientation. BuMines RI 8120, 1976, 13 pp. 

6. Diamond, W. P., G. W. Murrie, and C. M. McCulloch. Methane Gas Content 

of the Mary Lee Group of Coalbeds, Jefferson, Tuscaloosa, and Walker 

Counties, Ala. BuMines RI 8117, 1976, 9 pp. 

7. Drahovzal, J. A., W. E. Ward 11, and F. E. Evans, Jr. Fracture Analyses 

in a Selected Area of the Warrior Coal Field, Alabama (written for 

Bureau of Mines under research contract No. G0155028, Data Accumulation 

on Selected Coal Measures in the Warrior Basin of Alabama). Geol. 

Survey of Ala., Open File Rept. 1976, 97 pp.; available for consultation at Geol. Survey of Ala., Tuscaloosa, Ala. 

8. Ehrlich, R. The Geologic Evolution of the Black Warrior Detrital Basin. 

University Microfilms, Inc., Ann Arbor, Mich., 1963, 64 pp. 

9. Fern, J. C., R. Ehrlich, and T. L. Neathery. A Field Guide to Carboniferous ~etrital Rocks in Northern Alabama. Geol. Soc. America, Ann. 

Field Trip, 1967, 101 pp. 

10. Hobday, D. K. Beach and Barrier -Island Facies in the Upper Carboniferous 

of Northern Alabama. Geol. Soc. America, Special Paper 148, 1974, 

pp. 209-223. 

11. King, P. B. The Subsurface Ouachita Structural Belt in the Ouachita 

System. Univ. of Texas, Pub. 610, 1961, pp. 83-97. 

12. iss sell, F. N., and M. Deul. Effect of Coal Breakage on Methane mission. 

SME-AIME Trans., v. 256, 1974, pp. 182-184. 

13. Kissell, F. N., C. M. McCulloch, and C. H. Elder. The Direct Method of 

Determining Methane Content of Coalbeds for Ventilation Design. 

BuMines RI 7767, 1973, 17 pp. 
McCalley, H. Reports on the Warrior Coal Basin. Geol. Survey of Ala., 

Special Rept. 10, 1900, 327 pp. 

~cculloch, C. M., and M. Deul. Geologic Factors Causing Roof Instability 

and Methane Emission. The Lower Kittanning Coalbed, Cambria County, 

Pa. Bwines RI 7769, 1973, 25 pp. 

McCulloch, C. M., J. R. Levine, F. N Kissell, and M. Deul. Measuring 

the Methane Content of Bituminous Coalbeds. BuMines RI 8043, 1975, 

22 PP 

McCulloch, C. M., S. W. Lambert, and J. R. White. Determining Cleat 

Orientation of Deeper Coalbeds From Overlying Coals. BuMines RI 8116, 

1976, 19 pp. 

Nickelsen, R., and V. D. Hough. Jointing in the Appalachian Plateau of 

~ennsylvania. Geol. Soc. America, Bull., v. 78, 1967, pp. 609-630. 

Semes, D. R. Oil and Gas in Alabama. Geol. Survey of Ala., Special 

Rept. 15, 1929, 408 pp. 

Thomas, W. A. Converging Clastic Wedges in the Mississippian of Alabama. 

Geol. Soc. of America, Special Paper 148, 1974, pp. 187-209. 

Thomas, W. A. (ed.). Ouachita Influence on Mississippian Lithofacies in 

Structural Development of the Southernmost Appalachians. Geol. Survey 

of Ala., 3d Ann. Field Trip, 1965, pp. 23-28. 
APPENDIX A.--SURFACE JOINT READINGS OF INDIVIDUAL QUADRANGLES 

NOTE: Numbered trends are arranged by increasing divergence from north and not by th

dominance. Trends within the same vertical column of a directional group (ea

are assumed correlative. 

Quadrangle 

Tier 1: 

....... Carbon Hill 

Degrees deviation. 

Directional mean. . Tier' 2 : 

Howard. ........... Townley ........... Jasper ............ Cordova ........... Sipsey ............ Creel ............. Warrior ........... Degrees deviation. 

Directional mean.. 

Tier 3 : 

Berry ............. Oakman ............ Parish ............ ....... Goodsprings 

.............. Dora 

......... Brookside 

........ Gardendale 

Pinson ............ Degrees deviat ion. 

Directional mean. . 
Quadrangle 

Tier 4 : 

Berry SE .......... ............. Wiley 

Tutwiler School ... Gilmore.... ....... I 

Sylvan Springs. ... Adamsville ........ Birmingham North.. 

Degrees deviation. 

Directional mean.. 

Tier 5: 

Samantha NE... .... Searles NW........ 

....... Searles NE. 

Yolande NW........ 

Yolande NE.. ...... Bessemer.. ........ Degrees-deviation. 

Directional mean.. 

Tier 6 : 

Samantha SE. ...... Searles SW ........ Searles SE. ....... Yolande SW... ..... Yolande SE... ..... Degrees deviation. 

Directional mean.. 

Tier 7: 

Cottondale.. ...... Coaling ........... Degrees deviation. 

Directional mean.. 

- 

1 

- 

N 7' W - 

- 

- 

N 2" W 

- 

5 

N 5" W 

N 9" W - 

- 

- 

- 

- 

- 

N 9" W 

- 

N 1' W 

- 

- 

N 7' W 

6 

N 4' W 

N 8" W - 

- 

N 8" W 

West 

2 

- 

N 20' W 

- 

3 

- 

- 

N32"~ 

- 

4 

- 

N39"~ 

- 

- -I 

- 

- 

- 

N 20' W 

N 22" W - 

N 19' W 

N19'~ - 

- 

3 

N 20" W 

- 

- 

N 18' W 

N 13' W - 

5 

N 16" W 

- 

- 

- 

- 

- 

- 

- 

- 

N 39" W 

- 

- 

N 37" W 

N 41' E 

- 

- 

- 

- 

N 33" W 

1 

N 33' W 

N 34' W - 

- 

- 

- 

- 

- 

N 34' W 

- 

N35'W 

- 

- 

- 

- 

N 35" W 

N 25' W 

N 27" W 

2 

N 26" W 

5 

N 52" W - 

- 

- 

- 

- 

N 54' W 

2 

N 53' W 

- 

- 

- 

- 

- 

- 

6 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- - I - 

- 

N 54' W 

N 55' W - 

- 

- 

1 

N55'W 

N56'W 

- 

- 

N 56" W 

7 

- 

N 63' W - 

- 

N 39" W 

- 

- 

N45'~ 

N 43' W 

- 

2 

N 44' W 

N 42" W 

N 42" W 

0 

N 42" W 

- 

N 61' W 

- 

2 

N 62' W 

N 58" W 

N 57' W - 

N6Z0w 

N6Z0W - 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

5 

N 60' W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 
Quadrangle 

Tier 1 : 

Carbon Hill.. ..... Degrees deviation. 

Directional mean.. 

Tier 2 : 

Howard ............ Townley ........... Jasper ............ Cordova ........... Sipsey ............ 

............. Creel 

Warrior ........... Degrees deviation. 

Directional mean.. 

Tier 3: 

Berry ............. Oakman ............ 

............ Parish 

Goodsprings ....... Dora .............. Brookside ......... Gardendale ........ Pinson.. .......... Degrees deviation. 

Directionalmean.. 

Tier 4 : 

Berry SE .......... Wiley ............. Tutwiler School.. . Gilmore ........... Sylvan Springs .... Adamsville ........ Birmingham North.. 

Degrees deviation. 

Directional mean.. 

East 

1 

- 

- 

- 

- 

- 

2 

- 

- 

- 

- 

- 

3 

- 

- 

- 

- I - - 

-1 - 

- 

- 

- 

- 

- 

- 

- 

N 7" E - 

- 

- 

N 7" E 

4 

N 43" E - 

N 43" E 

N 37" E 

N 24" E 

N 18" E 

N 19" E 

6 

N 20" E 

N 11" E - 

0 

N 8" E 

- I 

- 

- 

- 

N 60" E - 

N 67" E - 

5 1 

- 

- 

- 

N 51" E 

N 49" E 

N 35" E 

1 - N36"E N55"E 

- 

- 

N 31" E - 

- 1 N 51" E 

6 1 

N 69" E - 

N 69" E 

- - 

N 41" E - 

- 

- 

N 61" E - 

- 

N 66" E 

N 59" E 

N 67" E 

8 

N 63" E 

N 60" E 

N 64" E 

N 64" E - 

- 

- 

- 

4 

N 63" E 

- 

N 29" E - 

- 

2 

N 30" E 

- 

N 33" E - 

- 

- 

- 

- 

- 

N 33" E 

N 44" E - 

N 41" E 

N 39" E - 

N 35" .E 

- 

9 

N 40" E 

N 44" E 

N 44" E 

- 

- 

- 

N41°E 

N 37" E 

7 

N 42" E 

I N 2" E N 23" E 

7 -1 

N64" E I 

- 

- , 

N 47" E 

N 39" E 

7 

N 38" E 

. 

N 55" E - 

- 

- 

N 54" E - 

- 

4 

N 53" E 

- 

- 

- 

- 

- 

N54"E 

N 54" E 

0 

N 54" E 

N 6" E - 

N 12" E 

12 

N 7" E 

- 

N 1" E 

N 12" E 

N 11" E 

N 12" E - 

N 1" E 

11 

N 7" E 

- 

8 

N51° E 

N 16" E - 

- 

7 

N 20" E 

- 

- 

- 

- 

N 26" E 

N 22" E - 

4 

N 24" E 
Quadrangle 

Tier 5 : 

Samantha NE. ...... Searles NW........ 

Searles NE ........ Yolande NW. ....... Yolande NE ........ Bessemer..... ..... Degrees deviation. 

Directional mean.. 

Tier 6: 

1 

- 

- 

- 

- 

N 11" E - 

- 

N 11" E 

Samantha SE. ...... 

2 

- 

- 

- 

- 

- 

- 

- 

- 

N 8" E - 

- 

N 22" E - 

- 

- 

N 22" E 

- 

- 

- 

- 

3 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 30° E 

N 27" E 

3 

N 29" E 

- 

- 

- 

- 

Searles SW... ..... I - 

East 

Searles SE........ 

Yolande SW.. ...... Yolande SE ........ Degrees deviation. 

Directional mean.. 

Tier 7 : 

Cottondale ........ Coaling ........... Degrees deviation. 

Directional mean.. 

4 

N 41" E 

N 39" E - 

N40° E 

N 44" E - 

5 

N 41" E 

N 42" E 

N 44" E 

N38"E - 

- 

6 

N 8" E 

N 2" E 

- 

6 

N 6" E 

- 

- 

- 

- 

5 

- 

- 

N 52" E 

N59"E 

- 

- 

7 

N 56" E 

- 

- 

N56"E 

N 57" E - 

1 

N 41" E IN 57' E 

- 

N 37" E - 

N 37" E 

N 48" E 

N 51" E 

3 

N 50" E 

N 66

N 6
APPENDIX B.--SURFACE CLEAT READINGS OF INDIVIDUAL QUADRANGLES 

NOTE: Numbered trends are arranged by increasing divergence from north and 

not by their order of dominance. Trends within the same vertical 

column of a directional group (east or west) are assumed correlative. 

Quadrangle 

Tier 1: 

Carbon Hill.. ..... Degrees deviation. 

Directional mean.. 

Tier 2 : 

Howard. ........... Townley ........... Jasper ............ Cordova........... 

Sipsey ............ Creel ............. Warrior........... 

Degrees deviation. 

Directional mean.. 

Tier 3 : 

Berry ............. Oakman ............ Parish ............ Goodsprings ....... Dora.............. 

Brookside ......... Gardendale ........ Pinson ............ Degrees deviation. 

Directionalmean..N1lOW 

Tier 4: 

Berry SE .......... Wiley ............. Tutwiler School... 

Gilmore ........... Sylvan Springs .... Adamsville ........ Birmingham North.. 

Degrees deviation. 

Directional mean.. 

Tier 5 : 

Samantha NE. ...... Searles NW........ 

Searles NE. ....... Yolande NW........ 

Yolande NE........ 

Bessemer .......... Degrees deviation. 

Directional mean.. 

1 

- 

- 

- 

- 

- 

- 

N 6" W 

N 5" W - 

- 

1 

N 6" W 

- 

- 

- 

- 

- 

N 11" W - 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

2 

N 24" W 

- 

N 24" W 

- 

N 19" W 

N 22" W 

N 25" W - 

- 

N 16" W 

9 

N 21" W 

- 

N 24" W 

N 24" W - 

N 27" W - 

- 

- 

3 

N25"W 

N 22" W - 

- 

N 21" W 

N 24" W 

N 18" W 

N 17" W 

7 

N 20" W 

- 

N 23" W 

- 

N 19" W - 

- 

4 

N21°W 

West 

3 

N 45" W - 

N 45" W 

- 

- 

- 

N 37" W - 

4 

- 

- 

- 

- 

- 

- 

- 

- 

5 

- 

- 

- 

- 

- 

- 

- 

- 

N84"W - 

- 

N 84" W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N76"W - 

- 

N76"W 

- 

- 

- 

N 37" W 

N 33" W 

N 35" W 

- 

N 35" W 

- 

N 33" W - 

- 

2 

N34"W 

- 

- 

N 30" W 

- 

- 

N 40" W 

- 

10 

N 35" W 

N 37" W - 

- 

- 

N32"W 

- 

5 

N35"W 

I N63"W 

N 70" W 

7 

N 67" W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N65"W 

- 

- 

N65"W 
I East 

Quadrangle 

Tier 6 : 

Samantha SE....... 

Searles SW........ 

Searles SE. ....... Yolande SW. ....... Yolande SE. ....... Degrees deviation. 

Directional mean.. 

Tier 7: 

Cottondale........ 

Coaling ........... .Degrees deviation. 

Directional mean.. 

Tier 1: 

Carbon Hill ....... Degrees deviation. 

Directional mean.. 

Tier 2 : 

Howard............ 

Townley ........... Jasper ............ Cordova. .......... Sipsey ............ Creel............. 

Warrior........... 

Degrees deviation. 

Directional mean. . Tier 3: 

Berry ............. Oakman ............ Parish ............ Goodsprings ....... Dora... ........... Brookside. ........ Gardendale ........ Pinson ............ Degrees deviation. 

Directional mean.. 

West 

1 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

4 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

2 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

5 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

3 

- 

N 35' w 

N 34O W 

N 44O W 

- 

10 

N 38' W 

N 51° W 

N 41° W 

10 

N 46' W 
*US. GOVERNMENT PRINTING OFFICE 1976-703-ooi/4 

Quadrangle 

Tier 4 : 

Berry SE.. ........ Wiley ............. Tutwiler School.. . Gilmore........ ... Sylvan Springs.. .. Adamsville........ 

Birmingham North.. 

Degrees deviation. 

Directional mean.. 

Tier 5 : 

Samantha NE....... 

Searles NW.. ...... Searles NE.... .... Yolande NW.. ...... Yolande NE........ 

Bessemer.......... 

Degrees deviation. 

Directional mean.. 

Tier 6 : 

Samantha SE....... 

Searles SW........ 

Searles SE.. ...... Yolande SW........ 

Yolande SE........ 

Degrees deviation. 

Directional mean.. 

Tier 7 : 

Cottondale........ 

Coaling. .......... Degrees deviation. 

Directional mean. . 

6 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

5 

N 70" E - 

- 

N 67" E 

N65"E - 

N 67" E 

5 

N 67" E 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 68" E 

- 

- 

- 

N 68" E 

- 

- 

- 

- 

East 

7 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 81" E 

- 

- 

N 81" E 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

4 

- 

- 

N 63" E 

- 

- 

N 54" E - 

9 

N 59" E 

N 64" E 

- 

1 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 12" E - 

- 

N 12" E 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

2 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

3 

- 

- 

- 

- 

- 

- I - 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- N 63" E I iN 640 - 

- 

- 

- 

- 

- 

N 47" E 

N 43" E - 

4 

N 45" E 

- 

- 

- 

- 

N 63" E 

- 

1 

N 64" E 

- 

N 54" E 

N 57" E - 

- 

3 

N 56" E 

N 56" E 

N 53" E 

3 

N 53" E ----