Bureau of Mines Report of Investigations/l975 

Selected Geologic Factors Affecting 

Mining of the Pittsburgh Coalbed 

UNITED STATES DEPARTMENT OF THE INTERIOR 
UNITED STATES DEPARTMENT OF THE INTERIOR 

Thomas S. Kleppe, Secretary 

Jack W. Carlson, Assistant Secretary-Energy and Minerals 

BUREAU OF MINES 

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

McCulloch, Charles M 

Selected geologic factors affecting mining of the Pittsburgh coalbed, by C. M. McCulloch [and others. Washington] U.S. Bureau of Mines [1975] 

72 p. illus., tables. (U.S. Bureau of Mines. Report of investigations 8093) 

Includes bibliography. 

1. Coal mines and mining-Pennsylvania . 2. Coal mines and 

mining-West Virginia. 3. Methane. I. U.S. Bureau of Mines. 

11. Title. 111. Title: Pittsburgh coalbed, Pennsylvania and 

West Virginia. (Series) 

TN23.U7 no. 8093 622.06173 

U.S. Dept. of the Int. Library 
CONTENTS 

Page 

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

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

Acknowledgments ......................................................... 3 

Historical background ................................................... 3 

Structure and stratigraphy of the Pittsburgh coalbed .................... 4 

Regional structure and paleogeography .............................. 4 

Thickness and rate of accumulation ................................. 6 

Generalized stratigraphy of the Pittsburgh Formation ............... 11 

Overburden thickness above the Pittsburgh coalbed .................. 12 

Geologic factors contributing to mining problems ........................ 13 

Strata above the Pittsburgh coalbed ................................ 14 

Sandstone channels ................................................. 17 

Clay veins ......................................................... 19 

Cleat within mines ................................................. 27 

Determination and analysis of cleat orientation ............... 27 

Relationship of local structure to cleat orientation .......... 28 

Geologic factors affecting methane emission ........................ 30 

Example of geology-related problems in a working mine .............. 32 

Determination and analysis of joints and photolinears ................... 36 

Surface joint determination ........................................ 37 

Surface joint analysis ............................................. 37 

Photolinear interpretation from infrared photographs ............... 42 

Photolinear analysis ............................................... 42 

Ronchi inspection of photoindex sheets and analysis of trends ...... 44 

Criteria for cleat estimation ...................................... 47 

Relationship of cleat to surface joints and photolinears 

overlying individual mines ....................................... 48 

Summary of directional data analysis ............................... 50 

Relative costs of cleat estimation by the three methods of 

analysis of surface directional data .................................. 50 

Field mapping ...................................................... 50 

Infrared photography analysis ...................................... 51 

Ronchi inspection of photolinear sheets ............................ 51 

Sunanary ................................................................. 51 

Bibliography of previous work in the Pittsburgh coalbed ................. 54 

Appendix A.--Glossary of terms .......................................... 63 

Appendix B.--Surface joint readings of individual quadrangles ........... 66 

Appendix C.--Photolinear readings of individual quadrangles ............. 69 

Appendix D.--Principal direction for individual photoindex sheets 

of the study area ...................................................... 72 

ILLUSTRATIONS 

1 . Map of the study area and the portion underlain by the 

Pittsburgh coalbed ................................................. 2 

2 . Structure map drawn on the base of the Pittsburgh coalbed ............ 5 

3 . Basin of deposition present in the study area during late 

Pennsylvanian time ................................................. 6 
ILLUSTRATIONS ..Continued 

Page 

Isopach of the Pittsburgh coalbed ................................... Location of data points for the study area .......................... Areas of the Pittsburgh coalbed that have been mined out ............ Overburden isopach of the strata above the Pittsburgh coalbed ....... Generalized stratigraphic column of the Pittsburgh Formation ........ Fence diagram of the strata directly above the Pittsburgh coalbed 

for the study area ................................................ Map of the known sandstone channels cutting into the Pittsburgh 

coalbed ........................................................... Isopach of the Pittsburgh sandstone ................................. Map of the Shannopin and Robena mines with sandstone cutouts. ....... Fence diagram of the strata above the Pittsburgh coalbed at 

the Shannopin mine ................................................ Generalized cross section of clay veins intersecting coalbeds ....... Mines operating in the Pittsburgh coalbed with abundant clay veins .. Location and structure around the Marianna No . 58 mine .............. Clay veins in synclinal trough at the Marianna No . 58 mine .......... X-ray diffraction charts of the clay vein, the roof rock, and 

the floor rock lithologies ........................................ Cleat systems in mines operating in the Pittsburgh coalbed .......... Composite rose diagram of cleat orientation in 18 mines surveyed .... Relationship between local structure and cleat orientation 

in the Pursglove No . 15 mine, Monongalia County, W . Va ............ Map of Federal No . 2 mine showing horizontally drilled holes 

and cleat directions .............................................. Structure map drawn on the base of the Pittsburgh coalbed for the 

area adjacent to the active workings of the Somerset No . 60 mine .. Fence diagram of the strata directly abwe the Pittsburgh coalbed 

adjacent to the active workings of the Somerset No . 60 mine ....... Sandstone channel probability map of the area adjacent to 

the active workings of the Somerset No . 60 mine ................... Rapid lateral variation in the strata directly above the 

Pittsburgh coalbed ................................................ Isopach of "draw slate" above the Pittsburgh coalbed in the area 

adjacent to the active workings of the Somerset No . 60 mine ....... Rose diagram of surface joint trends from the New Freeport 

quadrangle, Pennsylvania .......................................... Composite rose diagram of principal surface joint trends ............ Rose diagrams of surface joints for 39 quadrangles .................. Rose diagram of photolinears for 39 quadrangles ..................... Composite rose diagram of principal photolinear trends 

for entire area ................................................... Composite rose diagram of principal Ronchi trends for entire area ... 

TABLES 

Cleat systems of 18 mines surveyed .................................. Composition of gas from the Pittsburgh coalbed ...................... 
TABLES --Continued 

iii 

Page 

Average surface joint orientations, by county ....................... 38 

Principal surface joint trends in order of dominance. ............... 38 

Average photolinear orientations, by county ......................... 43 

Principal photolinear trends in order of dominance .................. 43 

Average photoindex sheet linear orientations, by county ............. 45 

Principal Ronchi photoindex trends in order of dominance ............ 45 

Fundamental systems from directional data. .......................... 47 

Coal cleat, dominant surface joint, and photolinear orientations 

of the study area................................................. 49 

Time and cost requirements for measuring joints and photolinears 

for the study area................................................ 50 
SELECTED GEOLOGIC FACTORS AFFECTING MINING 

OF THE PITTSBURGH COALBED 

C. M. McCulloch. Wm Pm Diamondl' B. Mm Bench. l 

and Maurice Deul 

1 ABSTRACT 

As part of the Bureau of Mines methane control program, the Pittsburgh 

coalbed was studied in Washington and Green Counties, Pa. , and in Marion and 1 Monongalia Counties, W. Va., where this coalbed is now being mined at its 

Igreatest depth. The coalbed thickness appeared to be structurally controlled ; 

the bed was generally thinner near the axes of anticlines and thicker near the 

axes of synclines. The overburden isopach shows a similar relationship. Most 

of the clay veins in coal occur in the synclinal troughs, generally under 

sandstone roof. 

Cleat orientations measured in 18 underground mines showed that face 

cleats are perpendicular to the axial trends of the folds, and the butt cleats 

are parallel to the axial trends, indicating structural control of the cleat. 

Measurement and analysis of surface joint orientations provide a method 

for predicting the cleat orientations of the coalbed, but linears measured 

from infrared photographs and photoindex sheets helped only to determine 

regional trends. 

The results of these investigations provide a geologic framework for 

rational planning for underground mine development to use the best available 

technology to cope with methane emissions, coalbed discontinuities, and 

related ground support problems. 

I INTRODUC TION I 

The Pittsburgh coalbed is one of the largest and most valuable mineral 

deposits in the world. It extends from the western tip of Maryland, west to 

Belmont County, Ohio, and from Allegheny County, Pa. , southwest to Putnam 

County, W. Va. This report is focused on Washington and Greene Counties, Pa., 

and Monongalia and Marion Counties, W. Va., because this is the area of 

greatest active mining. Within this area (fig. 1) the coalbed crops out only 

l~eologist. 

2~esearch supervisor. 
tion of data assembled by 

Latimer (7l) that the ~Gtsburgh coalbed had yielded 

about 8 billion tons of coal 

from the beginning of mining 

in the early 1900's to 

January 1, 1965. This total 

FIGURE 1. - Map of the study area and the portion under- was about 35 percent of the 

lain by the Pittsburgh coalbed. cumulative production of the 

Appalachian bituminous coal 

basin and 21 percent of the cumulative production of the United States. The 

coal reserves in western Washington and Greene Counties, Pa., and Marion and 

Monongalia Counties, W. Va., represent an important future source of coal. 

The coal here is deeper (up to 1,500 feet) than that previously mined in the 

Pittsburgh coal basin. Methane gas has been a continuing source of problems 

in the Pittsburgh coalbed, and such problems will probably increase with 

greater depth of mining. Roof instability and the occurrence of clay veins 

and sandstone channels are also possible. 

This report deals with selected geologic factors that affect the mining 

of the Pittsburgh coalbed. Selected factors examined include structure, 

3Underlined numbers in parentheses represent items in the bibliography preceding the appendixes. 
overburden, immediate roof strata, relation to joints and linears, and cleat 

orientations. 

Much of the Bureau of Mines methane control research has been conducted 

in the Pittsburgh coalbed (3, 64, 75). The present report gives results of 

one phase of this research, which is seeking to identify the geologic factors 

that in£ luence methane accumulations and emissions in coalbeds and which may 

be used in planning the degasification and ventilation of coal mines and the 

recovery of mine gas. Similar studies can be conducted on other coalbeds. 

ACKNOWLEDGMENTS 

This project could not have been completed without the assistance of many 

people and companies. We thank Consolidation Coal Co., Bethlehem Mines Corp. , Eastern Associated Coal Corp., and Jones & Laughlin Steel Corp., who provided 

personnel to escort us in our underground studies and supplied core logs, mine 

maps, and other necessary data. 

We especially thank James Marshalek, supervisory mining inspec tor for the 

Mining Enforcement and Safety Administration (MESA); S. M. Linger, W. C. Doran, 

Jr., J. G. Tilton, and J. C. Patton of the Equitable Gas Co.; James Barlow of 

the West Virginia Economic and Geologic Survey; Herb Steinman of Jones & 

Laughlin Steel Corp. ; and W. Edmonds of the Pennsylvania Geological Survey 

for supplying information and reviewing the manuscript. 

The contributions of C. H. Elder and P. W. Jeran, Bureau geologists are 

acknowledged. They have spent considerable time on investigations of the 

Pittsburgh coalbed and were most helpful with suggestions and supplying data 

for the preparation of maps. 

HISTORICAL BACKGROUND 

The first investigation of the Pittsburgh coalbed dates back to 1759 when 

Kenny (52) referred to a coal being mined on the hills around Pittsburgh. 

Since that time, numerous investigations have resulted in more than 100 publications. See Bibliography. 

Nineteenth century investigators were concerned primarily with the stratigraphy of the area and the problems in working out stratigraphic boundaries 

(72, 85, 98-100, 107, 115). Rogers (100) in 1884 was one of the first to 

realize the importance of the Pittsburgh coalbed in the mining industry. 

The most comprehensive single work on the Pittsburgh coalbed is that published in 1954 by Cross (=), who studied the stratigraphy, petrology, origin, 

composition, and mining problems of the bed. Much of Cross' work is pertinent 

today, and his paper has served as a model for the present report. 

As would be expected for so important a deposit, mapping has been extensive. The early 1900's saw a flurry of activity, with the Pittsburgh coalbed 

being mapped in parts of all four counties of the study area by Clapp (18) , Munn (B), Hennen (g), and Hennen and Reger (46). The first detailed map 

showing the area underlain by the Pittsburgh coalbed in West Virginia, Ohio, 
and Pennsylvania was published by Burrough (16) in 1914 and was a fairly accurate map for the small amount of data available. 

The coal-bearing Upper Pennsylvanian and Lower Permian rocks of the Washington, Pa., area have been studied by Berryhill, Schweinfurth, and Kent (=), 

who prepared a number of isopach and lithofacies maps of the area. 

In 1972 Roen and Farrel (96) published a structure map drawn on the base 

of the Pittsburgh coalbed using published geologic maps of Pennsylvania, 

county reports from West Virginia and Pennsylvania, and coal company data. 

The 7-112-minute geologic quadrangles of Amity, California, Ellsworth, 

Hackett, Mather, Monongahela, Prosperity, Washington East, Washington West, 

and Waynesburg have been mapped by the U.S. Geological Survey. TheCarmichaels, 

Oak Forest, and Midway quadrangles have been covered in other studies. Geological maps of the Blacksville, Fairmont East and West, Grant Town, Morgantown North, Osage, and Rivesville 7-112 -minute quadrangles have been prepared 

by graduate students at West Virginia University. 

The stratigraphy of the Monongahela Group in West Virginia, Ohio, and 

Pennsylvania has been studied by Hoover (a), who prepared a series of isopachs on all major units from the Redstone to the Pittsburgh coalbed. The 

Pittsburgh-Redstone coal interval in West Virginia has also been studied by 

Conti (20). 

In preparation for the present report, underground geologic investigations were conducted in 18 mines operating in the Pittsburgh coalbed. Coal 

cleat orientations were measured, and the location and trend of sand channels 

and clay veins were obtained. Surface joints were measured to evaluate their 

relationship to cleat directions underground. An aerial photoanalysis was 

conducted to locate lineaments and evaluate their relationship to surface 

joints. Geologic factors in£ luencing roof control were also investigated. 

STRUCTURE AND STRATIGRAPHY OF THE PITTSBURGH COALBED 

Regional Structure and Paleogeography 

Most of the Pittsburgh coalbed lies in a broad, gently dipping basin. 

The basin is a highly dissected region of gently folded anticlines and synclines that decrease in intensity westward from the Allegheny structural front 

(fig. 2). The area is known physiographically as the Allegheny Plateau. The 

fold axes generally parallel the axes of the basin. The dip of the rocks is 

generally less than lo. The forces that produced the folding and subsequent 

erosion exposed, or brought near the surface, numerous coalbeds that otherwise 

would still lie deeply buried. 

Figure 2 is a structural contour map of the Pittsburgh coalbed by Roen 

and Farrel (96). The Bureau has drilled approximately 20 holes to the Pittsburgh coalbed within the study area, but the additional information obtained 

did little to alter the interpretation of- the structural trends. 
HARRISON COUNTY I 

FIGURE 2. - Structure map drawn on the base of the Pittsburgh coalbed (me 
and Conti (20) have made other paleogeographic investigations. 7 

Thickness and Rate of Accumulation 

A coal isopach (fig. 4) was prepared to give an idea of original minable 

coal in place. The interval measured included partings in the coal. It also 

included roof coal when not separated by more than 6 inches of shale or sandstone. It was constructed from more than 3,000 data points (fig. 5) derived 

from two sources, driller's logs of oil and gas wells and core logs from coal 

companies. The thickness data from the driller's logs, somewhat less reliable 

(probably '2 feet) than those obtained from the detailed core descriptions, 

were mapped as reported. The reliability of the driller's logs depends in 

part on how long ago the wells were drilled, the type of equipment used, and 

the exactitude of the driller. Core data description generally correlated 

well with oil and gas well driller's logs. Mined-out areas are depicted on a 

separate map (fig. 6) . Strip -mined areas, determined from the most recent 

topographic maps, are shown on the overburden isopach (fig. 7) .* 

4Both the isopach of the coalbed and the overburden isopach are available from 

the authors 'at scales of 1:24000 (one inch equals 2,000 feet). The isopach 

has a 100-foot contour interval on the 1:24000 maps. Also all other maps 

of the area are available on a scale of 1: 96000. 
FIGURE 4. - lsopach of the Pittsburgh coalbed. (Sandstone cutouts are not 

included.) 
miles to the west, begins in 

western Marion County, 

W. Va., and runs through 

central Greene County, Pa. , into Washington County. 

This trend generally lies on 

the eastern flank of the 

Robinson and Waynesburg 

synclines. A third trend 

overlies the Nineveh syncline of western Greene and 

central Washington Counties, 

Pa. 

The thickest coal measured was 16 feet in a core 

LEGEND hole in northern Monongalia :::.'. Data points County, W. Va. (fig. 4), near 

0 6 12 

Scale, miles 

the Pennsylvania border. 

Several thicknesses of 15 

feet were also obtained from FIGURE 5. - Location of data points for the study area. core descriptions in the 

same vicinity. 
24 Bethlehem No. 4 1 

25 Bethlehem No.44 

26 Consol No. 20 

27 Robena 

28 Nemacolin 

29 Crucible 

30 Bethlehem No. 51 

fJ Mined-out area 

(as of 1973) 

0 6 12 

Scale, miles 

FIGURE 6, - Areas of the Pittsburgh coalbed that have been mined out. 
LEGEND 

, Stripmine 

I 0-400ft 

400-800ft 

800-~200ft 

hmft phis L 

FIGURE 7. - Overburdbn isopoch of the strata above the Pittsburgh coalbed. 
Arkle (1) and Kent and Gomez (58) believe that the structures may have 

been "growing" during deposition, which could possibly explain the thinner 

coals near the axes of anticlines and the thicker coal deposits near the synclinal trough. Areas of low coal (less than 4 feet) are scattered throughout 

the area. Many have a preferred orientation, parallel to that of the regional 

structure. Some are closely associated with the anticlinal trends of the 

present structure. These thin areas may represent lower accumulation of plant 

material, greater erosion, or irregular surface of deposition. Several of the 

thin coal areas have a sinuous pattern suggestive of meandering streams and 

are probably the result of stream erosion. 

Hoover (47) attributed the variations in thickness of the Pittsburgh 

coalbed to four possible causes: (1) Greater abundance of plant growth in 

some parts of the coalbed relative to others, (2) better preservation of 

accumulated plant debris in some areas, (3) influx of coarser detrital materials that may have diluted part of the peat already formed or terminated 

plant growth, and (4) the presence of deeper water, which prevented terrestrial vegetation from becoming established. 

There were at least three other possible reasons for the variation in 

thickness: (1) Some parts of the swamp existed longer than others, (2) some 

areas may have been too high and dry to allow substantial plant growth, and 

(3) postdepositional erosion. 

The time required for formation of the Pittsburgh coalbed can be estimated from the theoretical rate of accumulation for an ideal coalbed as determined by Ashley (2). Approximately 10 years would be required for 1 foot of 

peat to form from accumulated plant material. Since compaction and dewatering 

due to burial would reduce 1 foot of peat to 1-118 inches, approximately 100 

years is required to produce 1 foot of compressed peat. The formation of 

1 foot of coal requires between 3 and 3-112 feet of compressed peat, equivalent to at least 300 years. Thus, a 6-foot thickness of Pittsburgh coal would 

theoretically require 1,800 years of accumulation of plant material. This is 

only a reasonable estimate and cannot be considered a firm rule because the 

maximum thickness of 16 feet, which would require 4,800 years for deposition, 

is immediately adjacent to thinner coals. This maximum thickness may be due 

to greater accumulation of plant material in low areas as it was washed down 

from surrounding heights. 

Generalized Stratigraphy of the Pittsburgh Formation 

The Monongahela Formation in western Pennsylvania was raised to group 

rank by Berryhill and Swanson (2) who divided it into two formations, the 

Pittsburgh, which includes dominantly calcareous rocks with the Pittsburgh 

coalbed as its basal member and extends to the base of the Uniontown coalbed; 

and the Uniontown, which includes the Uniontown coalbed and the overlying predominantly sandy rocks to the base of the Waynesburg coalbed. 

The Pittsburgh Formation (fig. 8) has five members: Lower, Redstone, 

Fishpot, Sewickley, and Upper. The Lower member includes the Pittsburgh coalbed at the base of the overlying Pittsburgh sandstone (when present). This 
- Redstone coalbed I 

Pittsburgh rider coal 

Pittsburah coal bed 

Redstone 

member 

Lower 

member 

FIGURE 8. - Generalized stratigraphic column of the 

Pittsburgh Formation. 

thickness ranges from 220 to 

450 feet and consists mainly 

of interbedded sandstone, 

siltstone, limestone, and 

shale with lesser amounts of 

coal and clay. In general, 

throughout the section the 

coals overlie the calcareous 

units but are separated from 

them by underc lays. The 

Pittsburgh coalbed is the 

most extensive and economically important part of the 

Monongahela Group. 

Overburden Thickness Above the Pittsburgh Coalbed 

An isopach (fig. 7) was prepared to display the thickness of rock overlying the Pittsburgh coalbed in the study area. The map was constructed by subtracting the elevation of the structure, drawn on the base of the coal from 

the topographic elevation. Overburden thickness ranged from zero, where the 

Pittsburgh coalbed crops out, to more than 1,500 feet. Generally, the coal is 

shallow on the axes of anticlines and deeper in the troughs of synclines. The 

deepest cover in the study area is in southwestern Greene County and western 
Monongalia and Marion Counties, where it averaged 1,200 feet with a maximum 

thickness of slightly over 1,500 feet. 

As mining progresses under deeper cover, methane control and other mining 

problems will undoubtedly intensify. As gas emission rates are measured by 

the Bureau for increasing depths, attempted correlations with overburden thickness will be made to develop a theoretical model of depth versus gas emission 

for the Pittsburgh coalbed. 

In Washington County the Pittsburgh coalbed crops out and is strip-mined 

in three localities (fig. 7). One outcrop in the western part of the county 

has no structural dependence. The other two occur on the axes of the Amity 

anticline and the top of the Westland dome. Maximum overburden thickness is 

slightly over 800 feet in the southwestern part of the county. Average thickness is approximately 400 feet. 

In Greene County the coalbed crops out and is strip-mined along the 

Monongahela River. The overburden reaches a maximum thickness of 1,400 feet 

in southwestern Greene County and averages approximately 800 feet. The area 

where the overburden is relatively shallow is roughly parallel to the axes of 

anticlines, and the areas of the greatest overburden are in the synclinal 

troughs. For example, the Nineveh syncline in the southwestern part of the 

county has an overburden of between 800 and 1,200 feet. Along the Washington 

anticline to the west, the overburden ranges between 400 and 800 feet. 

In Monongalia County there is stripping along the eastern edge of the 

Pittsburgh coalbed where itcropsout. Of the four counties, Monongalia'has 

the most extensive stripping of the Pittsburgh coalbed. The coalbed rapidly 

increases in depth to a maximum of 1,500 feet of overburden in the western 

part of the county. 

In Marion County the Pittsburgh coalbed crops out along the eastern part 

of the county. The central part of the county has an average of 400 feet of 

overburden, whereas the western part has between 800 and 1,200 feet of cover. 

Only small sections of Harrison and Wetzel Counties are covered in this 

study. In Wetzel County, the eastern part of which is included in this study, 

the overburden averages between 800 and 1,200 feet. In Harrison County, there 

is some outcrop and strip mining. The overburden averages approximately 400 

feet with a high of 1,300 feet along the border between Harrison County and 

Marion and Wetzel Counties. 

GEOLOGIC FACTORS CONTRIBUTING TO MINING PROBLEMS 

Geological investigations can identify many underground mining problems. 

Sand channels that may intersect and cut out the coal can be located in 

advance of mining by analysis of core hole logs, and their probable course and 

influence on future mining operations can be predicted (76). Clay veins can 

be located and their trends can sometimes be established so that high gas concentrations, frequently associated with clay veins, can be anticipated. 
A detailed map of the rock above the coalbed can be used to determine the 

length of bolts needed to anchor into competent strata for proper roof support. 

Such a map can also help to locate rock known to deteriorate rapidly when 

exposed t o a i r so that resin bolts can be used. 

Abnormal accumulations of water can be evaluated and perhaps related to 

fracturing of the roof rock or to a fault zone. These zones of weakness may 

also be responsible for high gas concentrations. 

A detailed analysis of surface joints above a mine area can be prepared 

and examined for a possible relationship to the coal cleat directions and roof 

joints. Local deviations in joint and cleat directions serve as a basis for 

modifying mine projections. The cleat and joint analyses also supply information related to roof stability. For example, excessive spalling of ribs when 

mining parallel to cleat directions can sometimes be corrected by rotating the 

direction of mining 45". 

Strata Above the Pittsburgh Coalbed 

The strata overlying the Pittsburgh coalbed vary locally and regionally 

as shown in the fence diagram (fig. 9). This figure was prepared using 77 

core logs, electric logs, and other data selected from more than 500 logs to 

best represent the regional stratigraphic trends. The most common rock type 

directly overlying the Pittsburgh coalbed is the "draw slate" or "roof slate" 

(miners' terminology), consisting of alternating thinly bedded, dark gray to 

black, fissile carbonaceous shale, coal stringers, and sandstone lenses. This 

draw slate unit is generally less than 4 feet thick, but thicknesses up to 12 

feet have been observed. 

In the central part of the study area, the most common rock types above 

the draw slate are limestone and calcareous and silty shales. Surrounding the 

central area is a sequence of shales and massive sands. Other areas of massive sand development are shown on the sandstone channel map (fig. 10). 

In Monongalia and Marion Counties, W. Va., the rocks above the coal and 

draw slate are predominantly limestone and shale, although the "limestone" of 

older core logs is more likely interbedded limestone, shale, and siltstone; in 

earlier years these rock types were not usually differentiated. The only sand 

deposits in these two counties are along the eastern margin of the area. 

The roof rock in Greene County, Pa., is similar to that in Monongalia and 

Marion Counties, W. Va. Limestone is still dominant in the south but 

decreases in importance toward the northern border where large sand bodies 

become more prominent. The Pittsburgh sandstone unit may be up to 80 feet 

thick. 

In Washington County, Pa., limestone dominates the southwestern portion, 

sandstone the southern and central area, and shale the northern portion. 

Throughout the area, a few coals are detected, but there appears to be no 

pattern to their occurrence. 
FIGURE 9, - Fence diagram of the strata directly above the Pittsburgh coalbed for the study area. 
LEGEND 

4 Sandstone cutouts 

Scale, miles 

FIGURE 10. - Map of the known sandstone channels cutting into the Pittsburgh 

coal bed, 
An isopach of the Pittsburgh sandstone prepared by Hoover (47) covers the 

known extent of the Pittsburgh sandstone in Monongalia and Marion Counties, 

Greene County, Pa. , and part of Washington County, Pa. (fig. 11). The 

bodies trend predominantly either to the northeast or northwest. 

portions of the sandstone especially seem to be oriented to the 

northeast, as are the axes of the folds, which again suggests some structural 

control. There is also the possibility that the sandstone bodies are sedimentologically controlled, as suggested by W. Edmonds of the Pennsylvania 

Geological Survey (personal comnication, available for consultation at 

Bureau of Mines Pittsburgh Mining and Safety Research Center, Pittsburgh, Pa.). 

The northeast-oriented bodies could be related to the strike of the strandline 

and could have formed as longshore b'ars. The northwest-oriented bodies could 

be down-paleoslope features such as alluvial valleys. A correlation may also 

exist between the thickness of the sandstone and areas of sandstone cutouts in 

the coal. 

I Sandstone Channels 

Sandstone channels are lenticular, sometimes sinuous bodies of sandstone 

extending into, and sometimes completly through, a coalbed. Figure 10 is a 

map of known sandstone channels in the Pittsburgh coalbed, encountered in 

underground mining operations. Cross (2) also reports a channel extending 

from southwestern Pennsylvania to Monongalia County, W. Va., generally paralleling the Monongahela River. The channel then turns westward at the 

Monongalia-Marion County border. 

Most of the known channels are within the present mine workings. Channels are difficult to detect in advance of mining because exploratory drilling 

of a mine property is frequently on 1-mile centers or more, whereas the channels are usually less than 2,000 feet wide. A much closer spacing, preferably 

2,000 or 3,000 feet, will enable more detailed mapping and predicting of sandstone channel trends in advance of mining. 

Even when a sandstone channel is not directly encountered in the core 

drilling, other evidence may suggest the proximity of one. The coal may 

become abnormally thick, sometimes even doubling in thickness near a sandstone 

channel by possibly washing to the side or by differential compaction. The 

sulfurcontentmay increase toward channel areas. Channels can also possibly 

be detected by analysis of the related sediments using sedimentological and 

paleodepositional techniques, but this would be beyond the scope of this 

paper. Donaldson and Morton (27) listed five criteria that may be helpful in 

predicting channels: (1) Presence of clay veins, (2) change in coal type, 

(3) increase in the number and thickness of partings, (4) increase in detri- 

( tals in the coal, and (5) a down-bowed parting. 
0 - 5 10 

Scale, mlles 

FIGURE 11. - lsopach of the Pittsburgh sandstone (48). 
Figure 10 also shows other mines where sandstone channels have occurred. 

Clay Veins 

Clay veins are wedges of indurated clays and silts that penetrate the 

coalbed from either above or below. They can be vertical (parallel to the 

cleat directions) or form an angle of about 45" with the vertical (parallel to 

shear directions ) (fig. 14). 

Clay veins encountered in mines are usually crooked, are frequently 

angular, and interfinger with the coal rather than forming smooth contact surfaces. They may be hard enough to damage mining equipment. Thickness normally ranges from 1 inch to several feet but may be up to 15 feet. A total 

length of more than 1,000 feet has been observed underground. 

There are two physical types of clay veins. The first occurs as inclusions within a clay-silt matrix and has a conglomeratic or brecciated appearance. The second type is composed of small interlocking lenslike masses of 

shale fragments with convoluted, slickensided surfaces. 
\ 

\ /- 

------I 

0 

U 

LEGEND . - 

+ Scale, feet Limy shale 

50 Limestone 

0 Shale 

0 a Sandstone 4,000 8,000 

Horizontal Coal 

FIGURE 13. - Fence diagram of the strata above the Pittsburgh coalbed at the Shannopin 

mine. 
, 

LEGEND 

0 

Sandstone Cloy vein 

Rl 

Coal 

Horizontal 

FIGURE 14. - Generalized cross section of clay veins intersecting coalbeds. 

Clay veins were found in the following mines operating in the Pittsburgh 

coalbed (fig. 15): Mathies, Bethlehem Nos. 41 and 44, Marianna No. 58, 

Gateway, Shannopin, and Vesta No. 5; all these mines have a predominance of 

sandstone in the immediate roof. Two other adjacent mines, Loveridge and 

Federal No. 2, show no clay veins, and their roof strata are predominantly 

shale :and limestone. 

The presence of clay veins can greatly affect mining conditions. They 

often form cells within which large volumes of gas are isolated under high 

pressure. A test hole drilled into a cell enclosed by such a clay vein measured a confined pressure of 263 lb/in2 (a). The gas flow from a 2-inch hole 

drilled horizontally into the coalbed through the clay vein at this point produced an average of 78,000 ft3/d of gas for a short time. When mining encounters such a cell, large volumes of gas are released rapidly into the mine 

creating an explosion hazard. Also the chance of an explosion is increased by 

the sparks that are generated when mining into clay veins with both continuous 

miners and lognwall systems. 
LEGEND 

Clay vein area 

0 6 12 

Scale, miles 

FIGURE 15. - Mines operating in the Pittsburgh coalbed with abundant clay 

veins. 
-300- Structure contour, 50+t interval 

Drawn on base of Pittsburgh coalbed 

Datum is mean sed level 

Mined-out area 

0 2 4 

Scale, miles 

FIGURE 16. - Location and structure around the Marianna No. 58 mine. 
\ 

LEGEND \ 

- 410- Structure contour, 5ft Interval 

Drawn on base of Pittsburgh coalbed 

+ Datum a mean sea level Syncllne axis 

> Cloy vetns 

0 2,000 

Scale, ft 

FIGURE 17. - Clay veins in synclinal trough at the 

Marianna No. 58 mine. 

research, it has been postulated that the clay veins 

intruded the coal after 

coalification had taken 

place. This conclusion is 

supported by the presence of 

coal fragments with good 

cleat development in clay 

veins. As the coal fragments were layered and the 

layers were parallel to the 

dip of the clay vein 

(fig. 14), it would appear 

that clay was not injected 

into cracks in peat as suggested by Raistrich and 

Marshall (90), but was 

forced into the coalbed 

after coalification. 

It appears that the 

clay veins in the Pittsburgh 

coal bed are probably the 

result of tectonism, as in 

the Marianna No. 58 and 
6 IIIIIIIIIIII III~ 

U 

a, A 

q 5- Sarnple,roofrock Quartz V) 

- 

C 

C 

s 4- 

0 

C 

Kool ini te 

8 3- 

0 

- 

I 2- 

v, + - 

2 I3 

Sample, clay vein \ 05 Quartz 

64 60 56 52 48 44 40 36 32 28 24 20 16 12 8 4 

SCAN, deg 

FIGURE 18. - X-ray diffraction charts of (A) the clay vein, (B) the roof rock, and (C) the 

floor rock lithologies. 

V) C 

\ 

E 4- 

C 

3 

o 

u5'11'11J'~~~~~

Sample, floor rock - 

Colci te 

3- 1 .Quartz 

0 
LEGEND 

/ Montour 4 

2 Mathies 

3 Westland 

4 Somerset GO 

5 Vesta 5 

6 Marianna 58 

7 Gateway 

8 Shannopin 

9 Humphrey 7 

/O Pursglove 15 

// Blacksville I 

/2 Blacksville 2 

13 Osage 3 

14 Arkwright 

/5 Federal 2 

/6 Consol 93 

/7 Loveridge 

/8 Consol 20 

,A ~utt cleat 

\Face cleat 

coal bed, 
Shannopin mines, although they may also be related to differential compaction 

in a depositional environment such as described by Wilson (124) in the central 

Missouri coals. This would explain the thick sandstone units found above them, 

whereas mines with limestone and shale roofs have no clay veins. The only 

known evidence of igneous activity within the study area is a peridotite dike 

found in Fayette and Greene Counties, Pa. The dike has been noted by Cross 

and others, and its presence has been confirmed by exposure in mine workings. 

The dike, which has been traced on the surface for approximately 15 miles, 

ranges in width from a few inches to several feet and tends to be perpendicular to the axial folds. The coal around the dike has been naturally "coked. " 

Cleat Within Mines 

Cleat is the natural vertical fracture system in bituminous c-oalbeds. It 

is usually composed of a fundamental system of two components (sets) at 90" to 

each other. The more dominant fracture plane is the face cleat; the minor 

fracture plane is the butt cleat. The face cleat is more continuous, crossing 

bedding planes in the coal and extending for many feet, and tends to be perpendicular to the fold axes. The butt cleat is short, is often curved, and is 

a discontinuous feature that frequently terminates against the face cleat. 

In the past, the orientation of the cleat in the Pittsburgh coalbed controlled the direction of mining. As coal tends to break along the cleats, it 

was easier to mine parallel to the cleat than at an angle to it. This has 

changed with the introduction of continuous miners, which mine as fast at an 

angle to the cleat as parallel to it. However, cleat is still very important 

because its orientation determines directional permeability which, in turn, 

determines the flow of methane and water into the mine workings (64, 75). 

When mining advances perpendicular to the face cleats, much more gas and water 

are emitted into mine workings than when the advance is parallel to the face 

cleat. 

Determination and Analys is of Cleat Orientation 

Cleat surveys were conducted in 18 mines operating in the Pittsburgh 

coalbed. The average cleat orientations were measured for each mine (table 1) 

and plotted according to geographic location (fig. 19). A composite rose diagram (fig. 20) was constructed using the values from table l. Two distinct 

peaks are present in the face and butt cleat directions. Two equally dominant 

fundametal cleat systems with directional trends approximately perpendicular 

are calculated for the study area. These two systems are N 76" W - N 17" E, 

with a 93" separation; and N 67" W - N 28" E, with a 95" separation. 

In southwestern Pennsylvania and northern West Virginia, the cleat sys - 

term rotate clockwise from south to north. In figure 20, the dominant 

N 17' E direction is composed of the measurements from mines in the southern 

portion of the area (Nos. 8 to 18 with the exception of No. 9), and the 

dominant N 28' E direction is composed of the measurements from mines in the 

northern portion of the area (Nos. 1 to 7 plus 9). The geographic plot of the 

cleat systems (fig. 19) gives a more detailed picture of the cleat rotation on 

a mine-to-mine basis. 
28 

TABLE 1. - Cleat systems of 18 mines surveyed 

A slight counterclockwise rotation of the cleat from east to west was 

also noted. Starting in the eastern part of the study area with Humphrey 

No. 7 (N 70" W), and continuing westward to Blacksville No. 1 (N 75" W) and 

Blacksville No. 2 (N 77" W) mines, the face cleat rotates 7". A similar 

rotation was detected between Consol No. 93 mine (N 73" W) and the Loveridge 

mine (N 80" W) to the west, and in the northernmost part of the study area 

between the Mathies mine 

(N 65" W) in the east and 

N the West land mine (N 70" W) 

in the west. 

Relationship of Local 

Structure to Cleat 

Orientation 

Cleat orientation and 

local structure are closely 

related. The butt cleats 

tend to be parallel to the 

axial trends of folds, 

whereas the face cleats are 

perpendicular to the axial 

36 readings total 0 trends. This has been noted 

I not only in the Pittsburgh 

scale of readings coalbed but also in the 

Pocahontas No. 3 (Virginia) , FIGURE 20. - Composite rose diagram of cleat orientation 

in 18 mines surveyed. 

Butt cleat 

N 25" E 

N 27" E 

N 25" E 

N 30" E 

N 30" E 

N 28" E 

N 28" E 

N 18" E 

N 27" E 

N 19" E 

N 20" E 

N 17" E 

N 17" E 

N 12" E 

N 17" E 

N 18" E 

N 15" E 

N 12" E 

No. 

North : 

I........ .... Z...... ...... 3............ 

4............ 

s............ 

6............ 

7. ........... 8. ........... g............ 

10 ............ 

11 ............ 12.. .......... 13 ............ 14.. .......... 15 ............ 

16 ............ 17 ............ South: 18 ...... 

Mine name 

Montour 4................. 

Mathies....... ............ Westland .................. Somerset No. 60 ........... Vesta No. 5. .............. Marianna No. 58 ........... Gateway ................... Shannopin. ................ Humphrey No. 7............ 

Pursglove No. 15 .......... Blacksville No. 1 ......... Blacksville No. 2.. ....... Osage No. 3............... 

Arkwright.. ............... Federal No. 2............. 

Consol No. 93 ............. Loveridge ................. Consol No. 20 ............. 

1 Face cleat 

N 65" W 

N 65" W 

N 70" W 

N 62" W 

N 66" W 

N 68" W 

N 68" W 

N 73" W 

N 70" W 

N 72" W 

N 75" W 

N 77" W 

N 75" W 

N 79" W 

N 77" W 

N 73" W 

N 80" W 

N 78" W 
the Lower Kittanning (Pennsylvania) , and the Har tshorne (Oklahoma) coalbeds 

(75) 

A good example of the relationship between local structure and cleat 

orientation in the Pittsburgh coalbed can be observed in the Pursglove No. 15 

mine, located in Monongalia County, W. Va. , between the area's two dominant 

structural features --the Fayette anticline and the Lambert syncline (fig. 21). 

Cleat orientations measured in the mine define a M 72" W - N 19" E fundamental 

system. The structural strike within this portion of the mine averages 

N 24" E, close to the N 19" E strike of the butt cleat. The structural dip is 

N 76" W, similar to the N 72" W trend of the face cleat. Similar (210") relationships between cleat orientation and local structural trends are observed 

for the majority of the mines surveyed. 

Scale, f t 

FIGURE 21. - Relotionship between local structure and cleat orientation in the Pursglove 

No. 15 mine, Monongalio County, W. Va. 
Geologic Factors Affecting Methane Emission 

The Pittsburgh coalbed is a gassy coalbed. According to Irani (50-51) 

the five counties in the United States producing the most coal gas are-- 

Monongalia County, W. Va.. ............. 40.7 

Marion County, W. Va................... 23.1 

Buchanan County, Va.. .................. 22.1 

Washington County, Pa.... .............. 12.4 

Greene County, Pa. ..................... 11.7 

Four of these counties are within the study area. They have a total gas production of 87.9 MM ft3 /d; approximately 95 percent is from mining in the 

Pittsburgh coalbed. Also Kim (60-61) has estimated that the Pittsburgh coalbed in southwestern Pennsylvania (over an area of 575 square miles) contains 

over 500 billion ft3 of methane in the virgin coal. 

Analysis of a number of gas samples collected from horizontal holes 

drilled from active faces into virgin coal (2) showed that their methane contents ranged from 84 to 96 percent (table 2). 

TABLE 2. - Composition of gas from the Pittsburgh coalbed, percent 

sion 

in id 

Gas 

CH, ......................... C2H6.... .................... CO .......................... 

O,........................... 

N2.......................... 

Although the 

is still not 

ent ifying cer 

total effect of the geology of a coalbed on its methane emiscompletely understood, considerable progress has been made 

tain controlling factors. Kissell and Bielicki (64) have 

found that an unfractured "solid" block of coal has a very low permeability, 

in contrast to high permeability in the coalbed where fracturing is extensive. 

The density of the fractures and the permeability of the coalbed depend on the 

coal rank. The low-volatile coals tend to be the most highly fractured. In a 

given coalbed, fractures are not uniform in size or spacing. This could be 

due to such factors as the degree of folding and faulting, proximity to fold 

axes, and the thickness of overburden. The in situ fracture spacing calculated for the Pittsburgh coalbed is 8 cm, as compared with 4.5 cm for the 

Pocahontas No. 3 coalbed, although observed fracture spacings may vary widely 

from these calculations. 

Sample 1 

88.91 

.04 

10.97 

.04 

.05 

Permeability should be greatest in the face cleat direction. In one area 

of a mine operating in the Pittsburgh coalbed, the methane emission from the 

solid ribs was significantly higher than the emission from the working face. 

It was observed that the rib intersected the face cleats and that the working 

face was draining the less permeable butt cleats (64). 

Sample 2 

95.86 

1.08 

2.54 

.06 

.46 

Sample 3 

93.85 

.04 

4.75 

.05 

1.20 

Sample 4 

84.4 

- 

14.75 

.02 

-65 
operating mines. Greater 

werburden pressures that 

may tend to close fractures 

and reduce permeability may 

be compensated for by a 

4- greater gas content of the 

deeper coals. 

Friability of the coal 

also affects methane emission. A core from the 

MAP Beckley or Pocahontas No. 3 

coalbed (both of which are 

friable), when allowed to 

degasify in a sealed container, gives off approximately 94 percent of its 

LEGEND total gas content, whereas 

I- 4 Measurement holes the same amount of Pittsburgh coal (which is blocky) 

under the same conditions 

Scole, ft gives off only 60 to 65 perFIGURE 22. - Map of Federal No. 2 mine showing hori- cent of its total gas. This 

also may be due to the zontally drilled holes and cleat closer cleat spacing in the 

directions, 
Beckley and Pocahontas No. 3 (114 inch) coalbeds, as compared with the Pittsburgh coalbed (1 inch). 

Geologic structure can also affect gas emission through its effect on 

waterflow. Even a dip of less than 1" can decrease the flow of gas because 

any water in the coal must be displaced uphill before gas can flow freely. 

Example of Geology-Related Problems in a Working Mine 

Typical struc ture-related problems were studied at Somerset No. 60 mine (s), which was being developed down the northwest flank of the Amity anticline towards a syncline (fig. 23). Water has been accumulating at the face 

of entries being driven to the northwest, which dip into the working face. 

Once the axis of the syncline is crossed, the floor will dip away from the 

face, allowing the water to run off. 

The N 62" W (face) and N 30" E (butt) cleat system is nearly orthogonal. 

The measured rock joint orientations are between N 57" W and N 75" W, corresponding roughly to the face cleat. Mining was originally parallel to the 

cleat orientations but at present is 45" to the previous working. According 

to the operators, this gives more stable ribs and roof. 

The immediate roof is generally coal. A weak slickensided claystone, 

generally up to 12 inches thick and overlying the coal, is removed during mining, leaving the "stable" rider coal. Study of roof falls shows the weak 

strata to be either micaceous sandstone with thinly interbedded shale, or 

alternating coals and slickensided claystones. 

In the western part of the mine workings there are sand channels that 

completely cut out the coal. To investigate roof conditions and the probability of sandstone channels in the area of future advancement adjacent to the 

active mine workings, a fence diagram (fig. 24) was constructed using data on 

the 40 feet of strata immediately above the Pittsburgh coalbed. The probability of the coal being cut out increases in areas where the rock type directly 

above the coal is predominantly sandstone and where the base of the sandstone 

approaches the top of the coal. Based on this consideration and on core data, 

a sandstone cutout probability map (fig. 25) was constructed. 
KEY MAP 

LEGEND 

Data points 

Mined-out area 

-700- Structure contour, 25-f t interval 

Drawn on base of Pittsburgh coalbed 

Datum is mean sea level 

Scale, ft 

FIGURE 23. - Structure map drawn on the base of the Pittsburgh coalbed for the area 

adjacent to the active workings of the Somerset No. 60 mine. 
FIGURE 24. - Fence diagram of the strata FIGURE 25. - Sandstone channel probability 

directly above the Pitts- map of the area adiacent to 

burgh coalbed adjacent to the active workings of the 

the active workings of the Somerset No. 60 mine. 

Somerset No. 60 mine. 

Zones of abrupt lithologic change often coincide with areas of unstable 

roof and high gas emission (53, 58, 75-76). The significant lithologic 

changes that can occur within a very short horizontal distance above the Pittsburgh coalbed are exemplified in figure 26 by two core holes (TH1 and TH2) 620 

feet apart and on opposite sides of the boundary between the zones of low and 

high probability shown in figure 25. The rapid change in lithology is due to 

the removal of stream erosion of approximately 20 feet of original sediments 

at the location of the TH2 hole along a stream channel that was subsequently 

filled with sand. More core drilling in the area adjacent to the active workings of the Somerset No. 60 mine could provide additional data to substantially refine the prediction of specific problem areas. The practice of spacing core holes 3,000 feet or more apart makes correlations and predictions 

difficult, especially where there are rapid changes in lithology and sedimentation patterns. 
FIGURE 26. - Rapid lateral variation in the strata directly above the Pittsburgh coalbed. 

Directly overlying the main bench (mined portion) of the Pittsburgh coalbed is an interval of variable thickness known as "draw slate" (fig. 27). 

This rock interval has very little strength and commonly fails, resulting in 

sudden gas emissions and rock haulage problems. Most miners prefer to anchor 

roof bolts in the more competent rock above the draw slate. The minimum bolt 

length that would be necessary to anchor into competent rock abwe the "draw 

slate" unit in any area can be determined from isopach maps like figure 27. 
widely spaced and most prom-. 

inent. Inspection of the 

LEGEND joint measurements for each 

rock type gives an overall 

Mined-out area 

view of the principal 

-6 - Contour interval, 3 ft trends. 

Photolinears are zones 

of weakness that generally 

FIGURE 27. - lsopach of "draw slate" above the Pitts- correlate with measured 

joint trends and may or may burgh coalbed in the area adjacent to the not be actual fractures active workings of the Somerset No. 60 observed in the field. In 

mine. areas of heavy vegetation or 

few outcrops, or during periods of bad weather for fieldwork, photolinear 

analysis is an alternative to the measurement of surface joints. 

The directional trends established by the various techniques indicate 

directions of inherent weakness in a coalbed and the rock surrounding it. An 

analysis of the fundamental directional systems in a virgin area prior to mine 

development can provide an estimate of the cleat system in a coalbed underground. This in turn determines the most efficient spacing of degasification 

holes for maximum gas flow, and to some extent, determines the most efficient 

mine development in directions that can minimize problems such as rib spalling 

and water and gas influx. 
Coal is the rock type 

most susceptible to the tectonic forces that produce 

directional trends that 

reflect structural weakness. 

The face and butt cleats measuredincoal underground are 

the direct result of these 

tectonic forces and are 

directly related to the 

regional structural trends. 

Because of the need to estimate the directional trend of 

cleat underground and the 

137 readings total 0 10 es tab lished-relationship of 

Scale of readings cleat tostructure, the cleat 

data are used as a standard 

FIGURE 28, - Rose diagram of surface ioint trends against which to judge the 

from the New Freeport quadrangle, reliability of data obtained 

Pennsylvania, by other methods. 

Surface Joint Determination 

Surface joints were measured over the thirty-nine 7-1/2-minute quadrangle 

s tudy area in southwestern Pennsylvania and northern West Virginia. An aver - 

age of 120 joint readings were taken per quadrangle with a minimum of 100 

readings per quadrangle and no more than 10 readings at a single outcrop. 

Rock types and quality of joints were noted at each outcrop. The directions 

were read as azimuths using damped Brunton compasses corrected for magnetic 

declination. To evaluate the principal directional trends, the data from each 

quadrangle were plotted individually on rose diagrams (fig. 28). By plotting 

only the dominant trends from each individual quadrangle on a single rose 

plot, a composite rose diagram (fig. 29) of surface joint trends for the study 

area was constructed. Joint orientations by tier (fig. 30) and corresponding 

counties from north to south are given in table 3. 

Surface Joint Analysis 

It was determined from the data shown in figure 29 that there are three 

major directional trends to the west and four to the east (table 4). The 

number directly above the directional trends in table 4 gives the order of 

dominance within the group, based on the number of readings comprising the 

peaks on figure 29. The assigning of the same order of dominance to two 

readings in the same group indicates equally strong directional trends. 
TABLE 3. - Average surface joint orientations, by county 

Tier I County I 1 I 2 I 3 1 4 I 5 I 6 I 7 

1, 2, 3 

4, 5 

6 

7 

8 

WEST 

N 33" WI - 

1, 2, 3 

4, 5 

6 

7 

8 

NOTE.--Numbered trends are arranged within the 2 directional groups (east and west) b

divergence from north and not by their order of dominance. Trends within the 

column of a group are assumed correlative. Directional data from the individu

are tabulated in appendix B. 

Washington.. . . . . . . . . . Greene... . ... .. . . . . .. Wetzel and Monongalia 

Marion and Monongalia 

Mar ion and Harrison. . 

TABLE 4. - Principal surface joint trends 

in order of dominance 

Washington ........... Greene. .............. Wetzel and Monongalia 

Marion and Monongalia 

Marion and Harrison.. 

N 6" W 

- 

- 

N 5" W 

N 7" W 

N-21" w 

N 19" W 

- 

N 20" W 

- 

N 7" E 

N 2' 

N 5" E 

N 2" E 

N 5" E 

- 

E'N 14" E 

N 13" E 

N 15" E 

N 14" E 

West 

I 

N 57" W 

N 76" W 

East 

111 

N 34" W 

- 

I 

N 15" E 

- 

I1 

N 27" E 

- 

111 

N 37" E 

- 

IV 

N 47" E 

- 
207 readinas total 

of read 

al (5.8) 

ings 

- 

Scale of readings 

FIGURE 29. - Composite rose diagram of principal surface joint trends. 

The principal directional trends listed in table 4 can be paired to form 

six fundamental joint systems: 

1. *N 57" W' and N 27" El' with an 84" separation. 

2. *N 57" W' and N 15" E' with a 72" separation. 

3. *N 57" W' and N 37" E' ' ' with a 94" separation. 

4. *N 76" W' and N 15" E' with a 91" separation. 

5. *N 76" W' and N 27" E' ' with a 103" separation. 

6. *N 34" W" ' and N 47" ElV with an 81" separation. 

The superscripts in Roman numerals indicate the order of dominance, and 

the asterisks indicate the most dominant trend of each system. Two surface 

joint systems (Nos. 2 and 4) are composed of joint sets of the first order of 

dominance. Both systems are composed of the N 15" E' set. System 4, with a 

91" separation, more closely approaches the ideal fundamental system's 90" 

separation than does system 2 with a 72" separation. System 4 (*N 76" W' - 

N 15" E') is quite similar in orientation to the *N 76" W' - N 17" E' cleat 

system established underground. The *N 76" W' set of system 4 is the most 

dominant set of system 4 and parallels the face cleat. The N 76' W' set could 

also be paired with the N 27" E" set (system 5), but the separation of 103" 
I 

I 

WETZEL 

COUNTY 

Eos Glodesville 

65 V 5 0 1 

New Freeport Hoibrook 

Glover Gap 

//5 

I 

r' 

HARRISON COUNTY 9 7 

Hundred" 

156 

- 

Oak Forest 

Monnlngton 

187 

MARION 

the face cleat orientation. 

/37 1 

Wadestown 

//7 \ 

-- 

The most dominant east - 

ern corn onents (N 15" E' and P N 27" E ' ) closely parallel 

the strike of the major 

structural axes of the area, 

and the western trend is 

nearly perpendicular to the 

axes. Therefore, the systems are probably directly 

related to the regional 

structural deformation. The 

sixth surface joint system 

(*N 34" W" ' - N 47" ElV) 

may also be related to the 

regional structure, although 

it is composed of sets of 

the third and fourth order 

/30 

Gorords Fort 

Gront Town 

300 

COUNTY 

143 -Indicates total readings 

- 

Scale, miles of dominance and not oriFIGURE 30. - Rose diagrams of surface ioints for 39 ented parallel to the cleat 

directions. This system is quadrangles. oriented at approximately 

45" to the *N 76" W' - N 15" E' system, which is within the theoretical angle 

of shears to the dominant trends. 

Mosontown 

Blocksv~lle 

143 

---- \ 

109 

~!ves;llle 

/44\ 

1% 

Osoqe 

/2/ 

MONONGALIA 

COUNTY 

South 

128 

I 

L: 

99 

Fjorth 

108 

126 . 
Wol loce 

724 

HARRISON COUNTY 0 - 7 

Scale, miles 

495 -Indicates total readings 

FIGURE 31. - Rose diagram of photolinears for 39 quadrangles. 

Sh~nnston 

423 

-~oirrnont West -Fo~rmont ~o;t 

'408-- \39// 

Glodesville 

384 
Additional evidence for the correlation of jointing with regional structure is the clockwise rotation of the joint trends in the study area; this is 

also observed for the trends of the major structural axes. The rose diagrams 

of the joint measurements from the individual quadrangles assembled in figure 30 illustrate the shift of the joint trends throughout the area. 

Photolinear Interpretation From Infrared Photographs 

Aerial photographs covering the 39 quadrangles of the study area were 

examined stereoscopically for photolinears. Photolinears are combinations of 

a great number of individual surface fractures that form distinctive alinements discernible on the photographs. They are zones of weakness that generally correlate with measured joint trends. An excellent photolinear study of 

a small portion of the study area was done by Hough (48) in 1960. 

In theory, photolinears that are a direct result of fracturing can be 

recognized as straight lines separating areas of tonal differences in open 

ground, linear topographic depressions, alinements of vegetation or taller 

than average trees, and shadow lines from cliff edges. In practice, farming, 

mining, and other manmade changes obscure most features that otherwise would 

be observable. Theref ore the interpretation of photolinears depends largely 

on straight segments of valleys and stream courses and on abrupt right-angle 

turns in streams and rivers. 

Photolinear Analysis 

The data from the infrared ~hotographs were used to prepare rose diagrams 

for each of the 39 quadrangles (fig. 31). The dominant photolinear directions 

for each quadrangle were determined from the rose diagrams (appendix C) and 

plotted on a single composite rose diagram (fig. 32). Directional data by 

tier and corresponding counties from north to south are given in table 5. 

Figure 32 shows five principal photolinear trends to the west and three 

to the east. Their order of dominance is given in table 6. 

The individual photo linear trends can be paired into six fundamental 

photolinear systems, with an asterisk indicating the dominant trend of each 

system: 

1. *N 65" W' and N 20" E' with an 85" separation. 

2. N 79" W" ' and *N 20" E' with a 99" separation. 

3. N 79" W' ' and *N 1" E' ' with an 80" separation. 

4. N 40" w"' and *N 20" E' with a 60" separation. 

5. *N 25" W' and N 75" El1 with a 100" separation. 

6. N 13" W" and *N 75" E' ' with an 88" separation. 
TABLE 5. - Average photolinear orientations, by county 

Tier 1 County 1 1 I 2 I 3 I 4 I 5 I 6 

T.rn C T WLIUJ. 

NOTE. --Numbered trends are arranged within the 2 directional groups (east and west) b

divergence from north and not by their order of dominance. Trends within the 

column of a group are assumed correlative. 

TABLE 6. - Principal photolinear trends 

in order of dominance 

- EAST 

N 52" W 

N 54" W 

N 51" W 

- 

N 52" W 

N 39" W 

N 41" W 

N 44" W 

N 43" W 

N 43" W 

N 63" E 

N 62" E 

- 

- 

N 63" E 

N 30" W 

- 

N 29" W 

N 30" W 

N 35" W 

N 21" W 

N24"W 

N 18" W 

- 

N 23" W 

N 37" E 

N 31" E 

N 32" E 

N 37" E 

N 38" E 

N 19" E 

N 20" E 

N 24" E 

N 25" E 

N 24" E 

West 

1, 2, 3 

4,5 

6 

7 

8 

N 51" E 

N 44" E 

N 54" E 

- 

N 50" E 

N 13" E 

- 

N 15" E 

N 15" E 

N 16" E 

East 

N 3" W 

N3"W 

N 4" W 

N 4" W 

N 3" W 

.......... Washington.. 

Greene ................ Wetzel and Monongalia. 

Marion and Monongalia. 

. Marion and Harrison.. 

N 4" E 

N 5" E 

N 2" E 

N 3" E 

- 

1, 2, 3 

4, 5 

6 

7 

8 

v 

- 

N 13" W 

I 

- 

N 20" E 

I 

- 

N 65" W 

N 12" W 

N14"W 

- 

N 11" W 

N 13" W 

Washington.. .......... Greene.. .............. Wetzel and Monongalia. 

Marion and Monongalia. 

. Marion and Harrison.. 

I1 - 

N 1" E 

I1 

- 

N 25" W 

I1 I 

- 

N 75" E 

111 

N 79" W 

N 40" W 
The first infrared photolinear system (*N 65" W' - N 20" El) is composed 

of the most dominant westerly set and the most dominant easterly set. This 

system best estimates the established *N 67" W' - N 28" Er coal cleat system. 

The *N 65" W' set is the most dominant of the system and it nearly parallels 

the face cleat. The N 20" E! set, if not paired with N 65" w', could be 

paired with an N 79" w"[ (system 2) which is similar to the *N 76" W' - 

N 17" E' cleat system. Photolinear system 2, however, contains one set of the 

third order and has a larger divergence from 90" than system 1. The 

N 79" W" I set can also be paired with N 1" ' s stem 3) for an 80" separa- 'Y tion. This system, while having one set (*N 1" E' ) which diverges 16" from 

the butt cleat of the *N 76" W' - N 17" E' cleat system, has one set 

(N 79" W' ") which diverges only 3" from the face cleat. System 3, however, 

is composed of one set of third order dominance, and more significantly, the 

most dominant set of the system (*N 1" El*) is in the butt cleat direction. 

The fourth, fifth, and sixth photolinear systems are each composed of one 

component of third or lower order of dominance and have no similarity to the 

established cleat systems. 

Ronchi Inspection of Photoindex Sheets and Analysis of Trends 

Thirteen photoindex sheets covering the study area were inspected for 

photolinears using a Ronchi-type defraction grating. The scale of the index 

sheets is 1 inch to 1 mile; hence only general trends can be differentiated, 

not specific linears. This method was investigated to determine its 
reliability as a relatively inexpensive, rapid reconnaissance procedure for 

delineating structural weakness. 

Principal directional trends as interpreted from the 13 individual index 

sheets of the area were plotted on a composite rose diagram (fig. 33). The 

individual trends established for each of the 13 sheets are presented in 

appendix D. Directional data by county from north to south are given in 

table 7. 

TABLE 7. - Average photoindex sheet linear orientations, 

by county 

EAST 

County I 1 1 2 I 3 I 4 

WEST 

Washington.. .......... Greene ................ Monongalia.. .......... Marion.. .............. 

NOTE.--Numbered trends are arranged within the 2 directional groups (east and west) by increasing divergence from north, not by order of dominance. 

Trends within the same vertical column of a group 

are assumed to be correlative. 

Washington. ........... Greene ................ Monongalia. ........... Marion ................ 

The rose diagram (fig. 33) shows four directional trends to the west and 

four to the east. Although the order of dominance of the directional trends 

does not stand out clearly in figure 33, it was established (table 8) for the 

data based on the strength of the image of the directional trends viewed 

through the Ronchi grating. 

TABLE 8. - Principal photoindex trends in order of dominance 

N 70" W 

N 69" W 

N 70" W 

N 73" W 

N 10" W 

N 8" W 

N 8" W 

N 8" W 

N 19" E 

N 11" E 

N 8" E 

I N 6" E 

The principal directional trends delineated by the Ronchi grating can be 

paired into five fundamental systems, with the superscripts again indicating 

the order of dominance and an asterisk the most dominant trend of each system. 

N 24" W 

N 23" W 

N 22" W 

N 24" W 

N 30" E 

N 25" E 

N 23" E 

N 20" E 

1. *N 70" w1 and N 27" E' with a 97" separation. 

N 45" W 

N 42" W 

N 43" W 

N 43" W 

West 

2. *N 70" W' and N 12" E~ ' with an 82" separation. 

N 51" E 

N 56" E 

N 58" E 

N 58" E 

East 

I 

N 70" W 

3. N 23" W" ' and *N 77" EI with a 100" separation. 

N 73" E 

N 79" E 

N 80" E 

N 78" E 

I 

N 77" E 

I1 

N 44" W 

I1 

N 77" E 

I11 

N 23" W 

IV 

N 9" W 

I11 

N 12" E 

IV 

N 55" E 
104 readings total 

Scale of readings 

FIGURE 33. - Composite rose diagram of principal Ronchi trends for entire area. 

4. *N 44" W" and N 55" EfV with a 99" separation. 

5. N 9" wiV and *N 77" E" with an 86" separation. 

The pairing of the most dominant westerly trend, *N 70" W' with either 

N 27" E' , the most dominant easterly trend, or N 12" E"' closely approximates 

the dominant trend of structural weakness as previously indicated from the 

analysis of cleat, surface joint, and photolinear orientations. The *N 70" W' 

is the most dominant trend of the first system and correlates with the face 

cleat. The components of the less dominant systems 3, 4, and 5 appear to be 

related to shears to the principal direcLiuzia1 trer~ds. 

A rotation of directional trends, similar to that observed for the cleat 

and surface joint trends, is apparent in a portion of the Ronchi derived data. 

The two trends at N 27" E1 and N 12" E"' on the composite rose diagram 

(fig. 33) appear to be parts of a weak bimodal peak. A review of the actual 

data for these two trends (appendix D, Nos. 1 and 3 east) shows that they are 

indeed two distinct trends with an easterly shift of the county directional 

means of 10" and 13O, respectively, from south to north. 
Criteria for Cleat Estimation 

The analysis of directional data yielded trends that could be paired into 

various combinations of fundamental systems (table 9). Two surface joint systems (1 and 4) correlated best with the established cleat systems. These two 

systems are composed of trends of the first and second order of dominance. 

Systems 2, 3, and 5 are composed of sets already paired in systems 1 and 4, 

and system 6 is composed of trends of third and fourth orders of dominance and 

is not similar to the cleat orientations. One infrared photolinear system (1) 

correlated with a cleat system and was composed of trends of the first order 

of dominance. An additional system (3) was reasonably correlative with the 

remaining cleat system, but was composed of second- and third-order trends. 

The second photolinear system is composed of trends already used in systems 1 

and 3. Systems 4-6 are not correlative with a cleat system and are composed 

of at least one trend of third or lower order of dominance. One photoindex 

photolinear system (1) correlated with a cleat system and was composed of 

trends of the first order of dominance, Even though system 2 would correlate 

with a cleat system, it is composed of one trend already used in system 1 and 

one trend of the third order of dominance. Systems 3-5 are not correlative 

with a cleat system and are composed of at least one trend of third or lower 

order of dominance. In each case where a directional data system correlated 

with a cleat system and was composed of trends of the first or second order of 

dominance, the most dominant trend correlated with the face cleat, 

TABLE 9. - Fundamental systems from directional data 

Photolinears (infrared 

photographs). 

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

group (east or west) for each data source, and an asterisk indicates 

the dominant trend of each system. 

Data source 

Cleat ........................... 

Surface joints .................. 

Photolinears (photoindex sheets) 

System 

*N 67" W' N 28" El 

J:N 76" W' N 17" El 

*N57"W1 N 27" EEt 

*N57"Wr N 15" E' 

*N57"W1 N 37" En' 

>kN 76" W' N 15" E1 

*N 76" WE N 27" E" 

*N34"WrE' N47"E" 

*N65"WB N 20" El 

N 79" W' ' *N 20" E' 

N 790 i':~ 10 

N 40" W* I' *N 20" Ef 

qq25"wtf ~75"~"" 

N 13" WV i':~ 750 E! 1" 

*N 70" W' N 27" EB 

*N 70" W' N 12" EEDD 

N 23" w"' *N 77" E" 

*N 44" w" N 55" ErV 

N go wiV +CN 770 E" 

System 

No. 

1 

2 

1 

2 

3 

4 

5 

6 

1 

2 

3 

4 

5 

6 

1 

2 

3 

4 

5 

Degrees of 

separation 

95 

93 

84 

72 

94 

9 1 

103 

81 

85 

99 

80 

60 

100 

88 

97 

82 

100 

99 

86 
The procedure proposed for the estimation of cleat orientation is based 

on the results of the directional data analysis summarized above. The pairing 

of the established sets into all reasonable combinations of fundamental systems is of primary importance in analysis of each type of directional data. 

Which system or systems are to be used to estimate the cleat orientation is 

based on the relative dominance of the sets of each system as determined by 

the number of readings comprising the corresponding peaks on rose diagrams. A 

system composed of the most dominant set and a perpendicular set of the first 

or second order of dominance will most likely give the best estimation of 

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

likely the face cleat direction. 

Cleat systems of similar, but different orientation may be present. Here, 

two regional fundamental joint systems were in fact composed of sets of the 

required orders of dominance, and correlated with the observed cleat systems. 

In the analysis of linears from infrared photographs and linears on photoindex 

sheets, one system satisfied the dominancy requirements and was correlative 

with one cleat system, and other systems were reasonably correlative with the 

remaining cleat system. But these other systems would be rejected because one 

component lacks the necessary relative dominance. The rejection of an estimator for the second cleat system is not detrimental as the two cleat systems 

are separated by only about 10". In all cases the directional systems not 

correlative with established cleat systems were rejected because they did not 

meet the dominance requirements, 

Rela tionship of Cleat to Surface Joints and Photolinears 

Overlying Individual Mines 

The relationship between coal cleats measured in individual mines and the 

directional trends established by measuring joints and photolinears directly 

overlying the mines was investigated utilizing the criteria established in the 

regional analysis. The most dominant directional systems measured with the 

degrees of deviation from the cleat directions are listed in table 10. An 

asterisk indicates the most dominant trend of each system. As with the 

regional data, surface joints provided the best estimation of cleat orientation. The most dominant surface joint system averaged within '7.4" of the 

face cleat and '6.6" of the butt cleat. It was possible to correctly predict 

the face cleat direction for 14 of the 18 mines using the surface joint data. 

The photolinear data were considerably less reliable, with averages of '23,7" 

for the face cleat and k19.4" for the butt cleat. The face cleat direction 

was correctly predicted in only 7 of the 18 mines. 

The high degree of divergence observed for the photolinear analysis is 

primarily the result of a dominant westerly photolinear trend in the vicinity 

of N 15"-30" W. This is similar to the second most dominant *N 25" W" trend 

observed on the photolinear composite rose diagram (fig. 32), and the 

N 34" w"' trend on the surface joint composite rose diagram (fig. 31). In 

several cases the second most dominant local photolinear system above the mine 

had an orientation similar to that of the cleat. 
TABLE 10 . . Coal cleat. dominant surface joint. and photolinear 

orientations of the study area 

No . 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

- 

Mine 

.............. Montour 4 

Mathies ................ Westland ............... . Somerset No 60 ........ Vesta No . 5 ............ 

. Marianna No 58 ........ Gateway ................ Shannopin .............. . Humphrey No 7 ......... . Pursglove No 15 ....... . Blacksville No 1 ...... . Blacksville No 2 ...... ............ Osage No . 3 

Arkwright .............. 

. Federal No 2 .......... . Consol No 93 .......... .............. Loveridge 

. Consol No 20 .......... Average divergence ..... 

Face 

cleat 

*N 65" W 

*N 65" W 

*N 70" W 

~'cN 62" W 

*N 66" W 

*N 68" W 

*N 68" W 

7'cN 73" w 

YcN 70" W 

7kN 72" W 

7kN 75" W 

;kN 77" W 

;kN 75" W 

*N 79" W 

;'cN 77" W 

*N 73" W 

fcN 80" W 

*N 78" W 

- 

Butt 

cleat 

N 25" E 

N 27" E 

N 25" E 

N 30" E 

N 30" E 

N 28" E 

N 28" E 

N 18O E 

N 27" E 

N 19" E 

N 20" E 

N 17" E 

N 17" E 

N 12" E 

N 17" E 

N 18" E 

N 15" E 

N 12" E 

- 

Surface joints 

N 55" W 

*N 60" W 

fcN 73" W 

>kN 65" W 

fcN 76" W 

9cN 72" W 

fcN 78" W 

i'cN 80" W 

7kN 80" W 

7kN 78" W 

~cN 66" W 

N 65O W 

N 82" W 

;kN 76" W 

;'cN 68" W 

N 80" W 

;kN 75" W 

;?N 91" W 

- 

Degrees of 

*N 37" E 

N 27" E 

N 23" E 

N 27" E 

N 14" E 

N 12" E 

N 13" E 

N 23" E 

N 20" E 

N 17" E 

N 27" E 

*N 13" E 

N 17" E 

N 19" E 

N 28" E 

;'cN 17" E 

N 17" E 

N 3" E 

- 

West 

10 

5 

3 

3 

10 

4 

10 

7 

10 

6 

9 

12 

7 

3 

9 

7 

5 

13 

7.4 

divergence. 

East 

12 

0 

2 

3 

16 

16 

15 

5 

7 

2 

7 

4 

0 

7 

11 

1 

2 

9 

6.6 

Photoline

Insufficient 

fcN 66" WI N 

Indetermina

N 6"W 

N 53" W 

N 70" W 

N 18" W 

N 26" W 

N 27" W 

N28"W 

YcN68" W 

YcN 66" W 

N 51" W 

f:N 66" W 

fcN 75" W 

*N57"W 

*N 53" W 

- 

N

*N 

*N 

N 

N 

N 

N

N

N 

N 

N59"W*N

N 

N 

N

N 
Analysis of directional data for a limited area is hampered by problems 

not normally encountered in a regional approach. Surface joint measurements 

are limited by the number and location of outcrops in the area of interest and 

at times by weather conditions. As outcrops become less numerous and farther 

from the area, the validity of the analysis decreases. Under these conditions, 

photointerpretation would perhaps be of benefit since it does not rely on outcrops for data, nor does it depend on the weather. However, photoanalysis, 

which depends on the availability of quality photographs and an experienced 

photointerpreter, is significantly less reliable than field measurements of 

joints. Both methods are limited by the small number of directional measurements usually obtainable for a small area. The fewer the data, the less 

likely are individual trends to stand out clearly, and this makes analysis 

difficult. 

Summary of Directional Data Analysis 

The estimation of regional underground cleat systems in coal by surface 

joint and photolinear analysis and Ronchi inspection is reliable within the 

established limits. The confidence level is least for Ronchi inspection 

results because the order of dominance of Ronchi trends is based largely on a 

visual impression of image "strength." Surface joint analysis is the only 

technique considered sufficiently reliable to be used on a local basis. 

RELATIVE COSTS OF CLEAT ESTIMATION BY THE THREE METHODS 

OF ANALYSIS OF SURFACE DIRECTIONAL DATA 

The relative costs and time requirements for the three analytical procedures are discussed below. 

F ie ld Mapping 

The mapping of surface joints requires approximately 2 days of fieldwork 

per 7 -112 -minute quadrangle by an experienced two-man team. An additional day 

is required for tabulation and analysis of data. Salary or consulting fee and 

field expenses for such a two-man team would amount to approximately $650 per 

7-112 -minute quadrangle. An area of 39 quadrangles, like the one investigated 

in this report, would require 33 weeks to evaluate (table 11) for a total cost 

of $25,350. 

TABLE 11. - Time and cost requirements for measuring joints 

and photolinears for the study area 

Time, weeks 

33 

39 

1 

Me th od 

Field measurement of surface joints ... Measuring linears from infrared 

photographs .......................... Measuring linears from photoindex 

sheets.. ............................. 

Cost 

$25,350 

25,460 

625 
Infrared Photography Analysis 

Interpretation of infrared photographs requires approximately 1 week per 

7-112-minute quadrangle for delineation and analysis of directional trends. 

Cost in this case would include $110 for infrared photo coverage and the salary or consulting fee of an experienced photointerpreter and would total 

approximately $650 per quadrangle. Photolinear interpretation of a 39- 

quadrangle area would take 39 weeks and would cost $25,460. 

Ronchi Inspec tion of Photo linear Sheets 

As already noted, cleat estimation by Ronchi inspection of photoindex 

sheets is somewhat less reliable than the two other methods, but it is far 

less expensive and time consuming. The total cost per 7 -112 -minute quadrangle 

is about $15. This is essentially the salary or consulting fee of a geologist, 

since cost of the photoindex sheet coverage for the whole 39-quadrangle area 

was only $40. An 8-quadrangle area could be evaluated in 1 day and the entire 

39 quadrangles in 1 week. Cost of the 1-week evaluation would be only $625. 

Ronchi inspection is especially attractive because this rapid and inexpensive reconnaissance technique can provide a good initial estimate of the 

cleat underground for subsequent checking by one of the two other methods. In 

an area of unknown cleat orientation, a combination of two or perhaps all 

three of the methods would be advantageous in that it would greatly increase 

the confidence level of the results. 

SUMMARY 

The Pittsburgh coalbed is one of the largest potential fuel resources in 

the world with respect to total tonnage of coal and the associated gas 

reserves. To aid in the efficient utilization of this deposit, a study was 

made of the southwestern Pennsylvania and norther West Virginia area which it 

underlies. The primary objective was to identify geologic factors that interfere with efficient mining and especially those factors that in£ luence gas 

migration in the coalbed. 

For this purpose, a map was prepared of all known sandstone bodies that 

intersect the coalbed. A correlation was found between areas of thicker sandstone and the occurrence of sandstone channels cutting into the coal. Prediction of sandstone channel trends is commonly hindered by the lack of sufficient subsurface data. Core drilling on the usual mile centers may entirely 

miss some of the sinuous, narrow sandstone channels. 

Clay veins were found and mapped in eight of the mines surveyed and tend 

to be clustered along the axes of synclines. Clay veins have been observed 

more frequently near channel sandstone bodies. Clay veins tend to intersect, 

forming boxlike cells that prevent gas migration. A hole drilled through two 

clay veins had pressures of 220 and 263 lb/in? on the virgin side and 0 lb/ina 

on the mined side (41). X-ray diffraction analysis of clay vein material and 

roof and floor rock indicates that in the mines investigated the clay material 

was injected after coalification from the roof and not from the floor. 
An isopach map of the Pittsburgh coalbed was constructed from more than 

3,000 data points. Wherever possible, strip mines were located and mapped. 

The coalbed thickness trends were oriented northeast to southwest, closely 

paralleling the regional structure. Areas of thick coal (8 feet plus) generally were located near synclinal troughs. Some areas of thin coal (less than 

4 feet) were located near the axes of the anticlines. Several other areas of 

low or thin coal had a sinuous pattern, suggesting a possible relation to 

ancient stream systems. 

A fence diagram was prepared of the strata above the Pittsburgh coalbed. 

The predominant rock type directly above the coalbed is a "draw slate" composed of thinly bedded, dark gray to black, fissile carbonaceous shale, coal, 

and sandstone, This unstable unit is generally less than 4 feet thick but may 

be as much as 12 feet thick. In Monongalia and Marion Counties, the rock 

above the draw slate is usually limestone and shale. In Greene County, limestone predominates in the south and sandstone in the north, reaching a maximum 

thickness of 80 feet. In Washington County there is a preponderance of limestone in the southwest, sandstone in the south and center, and shale in the 

north. 

A c lose relationship between overburden thickness and structure was 

established in Pennsylvania. In general, the coalbed was nearer to the surface along the axes of anticlines and deeper along the troughs of synclines, 

The overburden thickness ranged from zero at outcrop along the eastern edge of 

the study area to a maximum of 1,500 feet in western Greene and Monongalia 

Counties, The relationship was less well developed in West Virginia. 

Cleat surveys were completed in 18 mines operating in the Pittsburgh 

coalbed. Two similar, but slightly different cleat system (&N 76" W and 

N 17" E, *N 67" W and N 28" E) were established for the area, amounting to 

approximately a 10" clockwise rotation from south to north. A slight counterclockwise rotation of 4" to 7" was detected from east to west. A strong relationship was apparent between the cleat orientations and the local and 

regional structure. Face cleats tended to be perpendicular to the axial 

trends of folds, and the butt cleat tended to be parallel to the axial trends. 

The rotation observed for the cleat directions in general matches the rotation 

of the structural trends. 

The need for estimating the cleat systems in areas of virgin coal 

prompted the measurement and analysis of surface joints and the analysis of 

photolinears from infrared photographs and photoindex sheets. Although all 

three techniques provide reliable regional estimates of the cleat systems, 

surface joints provide the best estimate, especially on a local basis. Ronchi 

inspection of photoindex sheets is the fastest and cheapest method, but the 

level of confidence is better for the two other techniques. 

This report is a study of a large area and the problems that may be 

encountered in mining coal. The problems that can occur were noted, and pos - sible solutions and methods of detection of the trouble areas are offered. 

The project was implemented because a number of studies had been conducted on 

individual mines in the area and on individual quadrangles and selected areas, 
but no overall geologic study of this important coalbed had been attempted. 

Eighteen coal mines were studied underground, 39 quadrangles were mapped for 

surface joints and photolinears, and more than 3,000 core log descriptions 

were collected. 

It is hoped that the results presented in this report can serve as a 

framework for future mine planning and operations in the Pittsburgh coalbed. 

More detailed geologic studies dealing with specific problems of individual 

mines can be conducted as outlined by McCulloch and Deul (74). Because the 

methodology developed in this study can be applied to other areas, especially 

where there will be more underground coal mining, this approach is recommended 

for consideration by the mining geologists and engineers responsible for mine 

p laming. 
BIBLIOGRAPHY OF PREVIOUS WORK IN THE PITTSBURGH COALBED 

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and Green Series, Permian System, of the Appalachian Basin. Guidebook 

Series of the Geol. Soc. of America, Pittsburgh Meeting, 1959, 

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Arndt, H. H., P. Averitt, J. Dowd, D. H. Frandzel, and P. A. Gallo. 

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Paper 580, 1968, pp. 111, 102-120. 

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Survey in Western Pennsylvania and Parts of Eastern Ohio, Northern West 

Virginia, and Western Maryland. Pa. Geol. Survey IC 52, 1964, 10 pp. 

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Quad. Map GQ 283, 1964. 

Bishop, M. S. Subsurface Mapping. John Wiley & Sons, Inc., New York, 

1960, 198 pp. 
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County, Pa. U.S. Geol. Survey Bull. 300, 1907b, p. 145. 

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APPENDIX A. --GLOSSARY OF TERMS 

Anticline.--A fold in sedimentary rocks, convex upward with the sides 

dipping away from a common line,or crest. 

Autochthonous.--Describing coal that formed inplace, from the constituent 

plants that grew, accumulated, and degraded, without transport. 

Axial plane.--A plane that intersects the crest or the trough of a fold 

in such a manner that the limbs, or the sides of the fold, are more or less 

symmetrically arranged with reference to it. 

- Axis.--The intersection of the axial plane with a particular bedding 

plane. 

Basin of deposition. --Depression in which sediments accumulate. 

Bedding plane. --A surface that visibly separates successive layers of 

stratified rock (of the same or different lithology). 

Butt cleat. --A short, poorly defined joint or cleavage plane in a coalbed, 

usually oriented at right angles to the face cleat and terminating against it. 

Clay vein. --A body of clay, usually inducted, tabular to irregular in 

form, which fills a fissure in a coalbed. Clay veins are also known by the 

following miner's terms: Clay dikes, clay slips, clay seams, clay cutouts, 

mud fills, spars, and horsebacks. 

Coal cleat. --A joint or set of joints along which the coal is fractured. 

There are usually two cleat sets developed perpendicular to each other. (See 

butt cleat and face cleat.) 

Detrita1.--Applied to materials occurring in sedimentary rock that were 

derived from preexisting igneous, sedimentary, or metamorphic rocks and have 

usually been transported from place of origin. 

Dip.--The angle at which a stratum or any planar feature is inclined from 

the horizontal. The dip is at a right angle to the strike. 

Draw slate.--Soft shale that occurs above a coalbed and fails readily 

after the removal of the coal (also called roof slate). 

Eustatic.--A worldwide change in sea level as opposed to a relative 

change in sea level resulting from local coastal subsidence or elevation. 

Extension fracture. --Fractures that form parallel to the direction of a 

compressive force. In a sence they are tension fractures. 

Face cleat. --A well-defined joint or cleavage plane in a coalbed. The 

major set of joints in a coalbed. 
Fundamental system (joint system). --Two sets of prominent joints oriented 

at approximately 90" to each other. 

Interdistributary bay. --Restricted body of shallow, brackish or marine 

water located between distributary branches of a river in a deltaic depositional system. 

Isopach map. --A map that shows the variation of the interval (thickness) 

between two designated stratigraphic units or horizons or between any horizon 

and the surface; for example, a map prepared directly from two structurecontour maps by subtracting the elevations of the lower surface from those of 

the upper surface at each control point and drawing new contours. 

Joints. --Fractures in rock, generally more or less vertical or perpendicular to bedding, along which no appreciable movement has occurred. 

Linear or lineaments. --Straight or gently curved mappable physiographic 

features on the earth's surface. 

Lithofacies map. --A map based on lithologic characteristics showing variation in the lithologic makeup of a selected stratigraphic unit. The map may 

emphasize the dominant, average, or specific lithologic aspect of the unit, 

and provides information on the changing composition of that unit. 

Paleos1ope.--The direction of initial dip of a former land surface. 

Peridotite dike.--A vertical or nearly vertical igneous intrusion composed of coarse-grained plutonic rock composed chiefly of olivine. 

Rank of coal. --A generalized classification of coals according to degree 

of metamorphism, or progressive alteration, in the natural series from lignite 

to anthracite. 

Release fractures. --Fractures that form perpendicular to the major stress 

axes. These fractures are assumed to have formed when the load was removed, 

hence their name. 

- Rib. --The side wall of an outside entry in a coal mine. 

Rider coal. --A thin unminable coal found closely above a thicker minable 

coalbed. Normally only a few inches thick. 

Rose diagram. --Circular or semicircular diagram for plotting the frequency of measured strikes (or dips) of planar features, such as joints and 

cleats. 

Sandstone channel. --A body of sand deposited in the channel of a stream 

or river. 

- Set. --A group of essentially parallel related planar features, such as 

joints or dikes or faults, or clay veins. 
Shear fracture. --A fracture that results from opposed stresses which displace one part of a rock mass past the adjacent part. 

Slickenside. --Polished and striated (scratched or grooved) surf ace that 

results from friction along a plane. The movement can be very slight. 

Spalling of ribs or pillars.--The breaking off of layers of coal parallel 

to the surface of ribs or pillars in underground mines. 

Strandline.--The line or level at which a body of standing water, such as 

the sea, meets the land; for example, the shoreline. 

Strike.--The course or bearing of the intersection of an inclined bed or 

structure with the horizontal. It is perpendicular to the direction of dip. 

Structure contour map. --A map that portrays by means of lines drawn 

through points of equal elevation the subsurface configuration of a stratum 

such as a coalbed. 

Syncline. --A fold in sedimentary rock where the strata dip inward from 

both sides toward the axis. 

Sync1inorium.--A broad regional syncline on which are superimposed minor 

folds. 

Tectonic forces. --The forces involved in deformation of the earth's crust, 

resulting in folding and faulting. 

Washouts.--A channel cut into or through a coalbed during or after its 

deposition and generally filled with sands tone. 

Wild coal.--Brittle shale interstratified with thin coalbeds. 
APPENDIX B . - -SURFACE JOINT READINGS OF INDIVIDUAL QUADRANGLES 

Quadrangle West 

West 

1 I 2 I 3 I 4 I 5 I 6 

Tier 4: 

Windridge ......... Rogersville. ...... Waynesburg ........ Mather.. .......... Carmichaels. ...... Degrees separation 

Directional mean.. 

Tier 5 : 

New Freeport ...... Ho lbrook. ......... Garards Fort. ..... Oak Forest.. ...... Masont own. ........ Degrees separation 

Directional mean.. . County separation.. . County directional 

mean. .............. 

1 I 2 1 3 1 4 1 5 I 6 I 7 1 8 

N 22" W 

- 

- 

N 15" W 

N 17" W 

7 

N 18" W 

- 

- 

- 

N 19" W 

- 

- 

N 19" W 

1" 

N 19" W 

Tier 1: 

Avella.... ........ Midway.. .......... Cannonsburg ....... Bridgeville ....... Degrees separation 

Directional mean.. 

Tier 2 : 

West Middletown.. . Washington West.. . Washington East.. . Hackett.. ......... Monongahe la. ...... Degrees separation 

Directional mean.. 

Tier 3 : 

Claysville. ....... Prosperity ........ Amity ............. Ellsworth ......... California ........ Degrees separation 

Directional mean.. 

County separation.. . County directional 

mean............... 

WASHINGTON 

- 

N 21" W - 

- 

- 

N 21° W 

- 

- 

N 20" W 

- 

- 

- 

N 20" W 

- 

- 

- 

- 

- 

N 23" W 

GREENE 

- 

- 

- 

- 

N 26" W 

- 

N 26" W 

N 28" W 

- 

- 

N 32" W 

- 

4 

N 30" W 

4" 

N 28" W 

- 

N 7" W 

- 

- 

- 

N 7" W 

N 7" W 

- 

- 

N 8" W 

- 

1 

N 8" W 

- 

- 

- 

N4"W 

N 1" W 

3 

N 3" W 

5" 

N 6" W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 12" W 

N 12" W 

- 

- 

- 

0 

N 12" W 

- 

N 12" W 

COUNTY 

N 37" W 

N 32" W 

- 

N 26" W 

11 

N 32" W 

- 

- 

N 38" W 

- 

N31°W 

7 

N 35" W 

- 

- 

N 32" W 

N23OWN33"W 

N 32" W 

1 

N 32" W 

COUNTY 

- 

- 

- 

- 

N 37" W 

- 

N 37" W 

- 

N 43" W - 

- 

- 

- 

N 4-3" W 

6" 

N 40" W 

N 21" 30 W 1 N 33"0 W 

N 51" W 

N 58" W 

N 57" W 

- 

N 49" W 

9 

N 54" W 

- 

N 61" W 

N 61" W 

N 64" W 

N 56" W 

8 

N 61" W 

7" 

N 58" W 

- 

- 

- 

N 87" W 

- 

N 87" W 

- 

- 

N 49" W 

- 

- 

N 49" W - 

- 

N 49" W 

- 

- 

- 

N 77" W 

N 77" W 

N 70" W 

7 

N 75" W 

N 74" W 

N 77" W 

- 

- 

N 75" W 

3 

N 75" W 

0" 

N 75" W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 56" W 

N 52" W 

- 

N 60" W 

8 

N 56" W 

N 57" W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 81" W 

- 

- 

- 

N 81" W 

- 

N 81" W 

N 85" W 

- 

N 74" W 

- 

- 

- N 74" W 

N 70" W 

N 57" W N 73" W 

- 

N 82" W 

- 

- 

- 

N 82" W 

- 

- 

- 

- 

- 

- 

- 

5" 

N 53" W 

N 59" W 

N 52" W 

N64"W 

12 

N 57" W 

N 60" W - 

- 

- 

N 58" W 

2 

N 59" W 

3" 

N 76" W 

N 72" W 

N 67" W 

- 

9 

N 71" W 

N 76" W 

N 72" W 

N 75" W 

N 72" W 

N 71" W 

5 

N 73" W 

3" 
Quadrangle West 

1 I 2 I 3 I 4 I 5 1 6 I 7 

WETZEL AND MONONGALIA COUNTIES 

N81°W 

N 85" W - 

N 77" W 

N 76" W 

9 

N 80" W 

Tier 6: 

Hundred. .......... Wadestown.. ....... B lacksville. ...... Osage ............. Morgantown North.. 

Degrees separation 

Directional mean.. 

- 

- 

- 

- 

N 87" W 

- 

N 87" W 

- 

- 

- 

- 

- 

- 

MAR ION AND MONONGALIA COUNTIES 

- 

- 

- 

- 

- 

- 

- 

- N 47" W 

N 50" W 

N 57" W 

- 

10 

N 51" W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N64" W 

N 70" W 

N 66" W 

- 

- 

6 

N 67" W 

Tier 7: 

Glover Gap. ....... Manning ton. ....... Grant Town.. ...... Morgantown South.. 

Rivesville.. ...... Degrees separation 

Directional mean.. 

N 3" W 

- 

- 

- 

N 7" W 

4 

N 5" W 

MARION AND HARRISON COUNTIES 

- 

- 

N 23" W 

N 17" W - 

6 

N 20" W 

Tier 8 : 

Wallace ........... Shinnston.. ....... Fairmont West..... 

Fairmont East.. ... Gladesville ....... Degrees separation 

Directional mean.. 

N 50" W 

N 47" W 

N 52" W 

N 54" W - 

7 

N 51" W 

- 

- 

- 

- 

- 

- 

- 

- 

N 12" W - 

- 

N 2" W 

10 

N 7" W 

- 

- 

- 

- 

N 68" W - 

N 68" W 

N 84" W 

N 75" W 

N 80" W 

N 84" W - 

9 

N 81" W 

East 

1 I 2 I 3 I 4 I 5 I 6 I 7 1 8 

- 

- 

- 

- 

- 

- 

- 

Tier 1: 

Avella ............ Midway ............ Cannonsburg ....... Br idgeville. ...... Degrees separation 

Directional mean.. 

Tier 2 : 

West Middletown.. . Washington West.. . Washington East.. . Hackett.. ......... Monong ahe la. ...... Degrees separation 

Directional mean.. 

Tier 3 : 

C laysville. ....... Prosperity.. ...... Amity ............. Ellsworth.. ....... California. ....... Degrees separation 

Directional mean.. 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- N 7" E - 

- 

- 

- 

N 7" E 

- 

- 

- 

- 

N 35" W - 

N 35" W 

- 

- 

- 

- 

- 

- 

N 88" E - 

- 

N 89" E 

- 

1 

N 89" E 

- 

N 89" E 

- 

- 

- 

- 

N 89" E 

- 

N 17" E - 

N 19" E 

2 

N 18" E 

N 19" E 

N 17" E - 

- 

- 

2 

N 18" E 

N 19" E 

- 

- 

- 

N23"E 

4 

N 21" E 

- 

N 51" W - 

- 

- 

- 

N 51" W 

COUNTY 

- 

- 

- 

N 37" E - N 37" E 

N 37" E 

N 37" E 

- 

- 

N 37" E 

0 

N 37" E 

- 

- 

N 37" E 

- 

- 

- 

N 37" E 

WASHINGTON 

- 

N 28" E 

N 27" E - 

1 

N 28" E 

- 

- 

N29"E 

N 27" E 

N 27" E 

2 

N 28" E 

- 

N33"E 

N 27" E - 

- 

6 

N 30" E 

- 

- 

N 60" W 

N 58" W 

N 66" W 

5 

N 61" W 

N 46" E 

N 44" E 

N 45" E - 

2 

N 45" E 

N 47" E - 

N47"E 

N 47" E 

- 

0 

N 47" E 

- 

- 

- 

N 47" E 

N45OEN62"E 

2 

N 46" E 

- 

- 

N 80" W 

N 80" W - 

- 

N 80" W 

- 

N 63" E 

N 63" E 

N 57" E 

6 

N 61" E 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 63" E 

- 

- 

N 63" E 

N 89" W - 

- 

- 

- 

- 

N 89" W 

- 

- 

- 

- 

- 

- 

N 70" E - 

- 

N 69" E 

N69"E 

1 

N 69" E 

N75"E 

N 72" E - 

- 

- 

3 

N 74" E 
Quadrangle East 

1 I 2 I 3 I 4 I 5 I 6 1 7 I 8 

WASHINGTON COUNTY --Cont inued 

Tier 7 : 

Glover Gap.. ...... Manning ton. ....... Grant Town........ 

Morgantown South. . Rivesvi lle. ....... Degrees separation 

Directional mean. . 

East 

1 1 2 1 3 1 4 1 5 I 6 I 7 

Tier 8 : 

Wallace. .......... Shinnston ......... Fairmont West.. ... Fairmont East..... 

Gladesville. ...... Degrees separation 

Directional mean.. 

County separation.. . ....... 

MARION AND MONONGALIA COUNTIES 

I I I I 

2" 

County mean.. 

N 39" E 

- 

- 

- 

- 

- 

N 39" E 

N 37" E 

N 37" E 

N 37" E - 

0 

N 37" E 

2" 

N 38" E 

- 

N 46" E 

N 43" E - 

N44" E 

3 

N 44" E 

- 

- 

- N 52" E 

1 

N 53" E 

8" 

N 49" E 

- 5" 

N 80" E 

- 

N 82" E 

N 76" E 

N78" E 

6 

N 79" E 

N 77" E 

N 85" E - 

- 

8 

N 81" E 

2" 

N 80" E 

- 

N 26" E - 

- 

N 29" E 

3 

N 28" E 

- 

N 27" E 

N 27" E - 

0 

N 27" E 

1" 

N 28" E 

Tier 4 : 

Windridge. ........ Rogersville ....... Waynesburg. ....... Mather. ........... Carmichaels ....... Degrees separation 

Directional mean.. 

Tier 5 : 

New Freeport ...... Garards Fort.. .... Oak Forest.. ...... Masontown. ........ Degrees separation 

Directional mean.. 

County separation.. . County mean.. ....... WETZEL AND MONONGALIA COUNTIES 

- 

- 

- 

N 2" E - 

- 

N 2" E 

3" 2" 0" 

- 

- 

- 

- 

- 

- 

- 

N 2" E 

N 1" E - 

- 

1 

N 2" E - 

N 2" E 

MARION AND HARRISON COUNTIES 

I I I 

- N 10" E 

N 17" E - 

N 17" E 

7 

N 15" E 

N 7" E N 63" E,N 72" E 

0" 

- 

NIOOE 

N 14" E 

N 15" E - 

5 

N 13" E 

N 25" E 

N27"E 

N 27" E - N 27" E 

2 

N 27" E 

Tier 6 : 

Hundred. .......... Wadestown. ........ Blacksville.. ..... Osage ............. Morgantown North. . Degrees separation 

Directional mean.. 

N 19" E N 29" E N 89" E 

2" 

GREENE 

NIOOE 

N 9" E 

N 12" E 

N 13" E - 

4 

N 11" E 

N 16" E 

- 

- 

- 

- 

N 16" E 

5" 

N 14" E' 

N 7" E 

- 

N 3" E - 

- 

4 

N 5" E 

N 28" E - 

- 

N 22" E 

- 

6 

N 25" E 

COUNTY 

N23"E - 

- 

- 

- 

- 

N 23" E 

- 

- 

N 18" E 

N 22" E 

4 

N 20" E 

3" 

N 22" E 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 37" E - 

- 

N 37" E 

N 37" E N 46" E 

N 57" E - 

- 

N 54" E 

N 49" E 

8 

N 53" E 

N 74" E - 

N 70" E - 

- 

4 

N 72" E 

- 

- 

- 

- 

- 

- 

- 
APPENDIX C. --PHOTOLINEAR READINGS OF 

INDIVIDUAL QUADRANGLES 

West 

1 1 2 I 3 I 4 I 5 I 6 1 7 

Quadrangle 

GREENE COUNTY 

West 

1 I 2 I 3 I 4 1 5 1 6 I 7 I 8 

Tier 1 : 

Avella. ........... Midway. ........... Cannonsburg ....... Bridgeville. ...... Degrees separation 

Directional mean.. 

Tier 2 : 

West Middletown.. . Washington West.. . Washington East.. . Hackett ........... Monongahela.. ..... Degrees separation 

Directional mean.. 

Tier 3 : 

C laysville. ....... Prosperity ........ Amity. ............ Ellsworth ......... California. ....... Degrees separation 

Directional mean.. . 

County separation.. . County mean.. ....... 

Tier 4: 

Windr idge ......... Roger svi 1 le ....... Waynesburg ........ Mather. ........... Carmichae 1s. ...... Degrees separation 

Directional mean.. 

Tier 5 : 

New Freeport ...... Holbrook. ......... Oak Forest.. ...... Garards Fort.. .... Masontown ....... Degrees separation 

Directional mean.. 

County separation.. . County mean.. ....... 

N 1" W 

- 

- 

- 

- 

N 1" W 

- 

N 3" W 

- 

N 8" W 

N 6" W 

5 

N 6" W 

- 

- 

- 

N 2" W - 

- 

N 2" W 

5" 

N 3" 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 2" W - 

N 4" W 

2 

N 3" W - 

N 3" W 

N 13" W 

- 

N 12" W 

N 17" W 

N 13" W 

5 

N 14" W 

- 

- 

- 

- 

- 

- 

- 

- 

N 14" W 

- 

- 

- 

- 

- 

- 

N 10" W 

- 

- 

- 

- 

- 

N 10" W 

N13"W - 

N 14" W - 

- 

1 

N 14" W 

4" 

N 12" W 

COUNTY 

- 

- 

- 

- 

- 

- 

- N 29" W 

- 

- 

- 

- 

N 29" W 

- 

- 

N 30" W 

- 

- 

- 

N 30" W 

1" 

N 30" - - W - 

WASHINGTON 

N 22" W 

N 22" W 

N 18" W 

N 19" W 

4 

N 20" W 

N 24" W - 

N 23" W 

N 18" W - 

6 

N 22" W 

- 

N 20" W 

- 

N 20" W 

N 20" W 

0 

N 20" W 

2" 

N 21" W 

- 

N 29" W - 

- 

- 

- 

N 29" W 

- 

N 28" W 

N 25" W 

N 23" W 

N 29" W 

6 

N 26" W 

3" 

N 24" W 

- 

- 

- 

N 38" W 

- 

N 38" W 

- N 43" W 

N 40" W 

- 

- 

3 

N 42" W 

N37"W 

- 

- 

N 35" W - 

2 

N 36" W 

6" 

N 39" W 

N 43" W 

- 

N 35" W 

N 42" W 

N 34" W 

9 

N 39" W 

N 37" W - 

N 43" W 

N 47" W - 

10 

N 42" W 

1" 

N 41" W 

- 

- 

N 47" W - 

- 

N 47" W 

N57"W 

- 

- 

- 

N 57" W 

0 

N 57" W 

- 

N 53" W - 

N 53" W 

- 

0 

N 53" W 

10" 

N 52" W 

- 

- 

N 53" W 

- 

N 54" W 

1 

N 54" W 

- 

N 53" W 

- 

- 

- 

- 

N 53" W 

1" 

N 54" W 

- 

- 

N 64" W 

N 69" W 

5 

N 67" W 

- N 62" W 

N 67" W 

N 69" W - 

7 

N 66" W 

N60°W 

N 67" W 

N 69" W 

N 69" W 

N 68" W 

9 

N 67" W 

1" 

N 66" W 

N 61" W 

N 66" W - N 67" W 

- 

6 

N 65" W 

- 

- 

N 60" W 

N 62" W 

N 69" W 

9 

N 64" W 

1" 

N 65" W 

- 

N 80" W 

N 89" W 

- 

9 

N 85" W 

N88"W 

- 

N 90" W 

N 84" W 

N 80" W 

10 

N 86" W 

- 

- 

- 

N 83" W 

N 84" W 

1 

N 84" W 

2" 

N 85" W 

- 

- 

N 73" W - 

N 77" W 

4 

N 75" W 

N 77" W 

- 

- 

N 76" W 

- 

1 

N 77" W 

2" 

N 76" W 
-- - - - - 

Tier 1 : 

Avella. ........... Midway ............ Cannonsburg ....... Br idgevi 1 le ....... Degrees separation 

Directional mean.. 

Tier 2 : 

West Middleton .... Washington West.. . Washington East.. . Hackett ........... Monongahe la. ...... Degrees separation 

Directional mean.. 

Tier 3 : 

C laysvi lle. ....... Prosperity. ....... Amity ............. Ellsworth. ........ California.. ...... 

- 

Quadr ang le 

- WASHI 

- 

- 

N 13" E - N 13" E 

- 

N 14" E 

- 

N 10" E - 

West 

1 I 2 I 3 I 4 I 5 I 6 I 7 I 8 

'GTON COUNTY 

- - 

N 19" E - 

N 15" E - - - 4 - N 17" E - 

WETZEL AND MONONGALIA COUNTIES 

- 

- 

- 

N 51" W - 

- 

N 51" W 

- 

N44"W - 

- 

- 

- 

N 44" W 

N 28" W 

- 

- 

N 29" W 

N 29" W 

1 

N 29" W 

MARION AND MONONGALIA COUNTIES 

N62"W 

N66"W 

N 68" W 

N 63" W 

- 

6 

N 65" W 

Tier 6: 

Hundred. .......... Wadestown. ........ B lacksville ....... Osage. ............ Morgantown North. . Degrees separation 

Directional mean.. 

- 

- 

- 

N 76" W 

N 72" W 

4 

N 74" W 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 4" W 

- 

N 4" W 

- 

N18"W - 

- 

- 

- 

N 18" W 

- 

N 61" W 

N 60" W 

N 59" W 

N 65" W 

6 

N 61" W 

- 

- 

- 

- 

- 

- 

- 

N 77" W - 

N 75" W 

N 84" W 

N 85" W 

10 

N 80" W 

MARION AND HARRISON COUNTIES 

N 32" W 

- 

- 

N 30" W 

N 29" W 

3 

N 30" W 

Tier 7 : 

Glwer Gap.. ...... Manning ton. ....... GrantTown ........ Rivesvi lle. ....... Morgantown South.. 

Degrees separation 

Directional mean.. . 

- 

- 

- 

- 

N 43" W 

- 

N 43" W 

N 6" W - 

NlOW - 

- 

5 

N 4" W-N 

- 

- 

- 

- 

N 11" W - 

11" W. 

- 

- 

- 

- 

- 

- 

- 

I East 

N 50" W 

N 53" W - 

- 

- 

3 

N 52" W 

- 

N 68" W - 

N 69" W 

N 69" W 

1 

N 69" W 

N 76" W - N 82" W 

- 

- 

6 

N 79" W 

Tier 8 : 

Wallace. .......... Shinnston ......... Fairmont West.. ... Fairmont East..... 

Gladesville.. ..... Degrees separation 

Directional mean.. 

- 

- 

N 43" W 

- 

- 

- 

N 43" W 

- N3"W 

- 

- 

- 

- 

N 3" W 

N 20" W 

- 

- 

- 

N 25" W 

5 

N 23" W 

- 

- 

N 14" W 

N 14" W 

N 12" W 

2 

N 13" W 

N 36" W 

N 33" W - 

- 

- 

3 

N 35" W 
-- - - -- 

Quadr ang le East 

County mean.. ....... I N 4' E ( N 13" E 1 N 19" E 1 N 37" E 1 N 51" E 1 N 63" E I N 78" E 

I 1 I 2 1 3 1 4 I 5 I 617 

WASHINGTON COUNTY--Continued 

10 

N 78" E 

0" 

- 

- 

4" 

Tier 4 : 

Windridge.. ....... Rogersville ....... Mather.. .......... Carmichaels.. ..... Waynesburg ........ Degrees separation 

Directional mean.. 

Tier 5 : 

New Freeport ...... Holbrook.. ........ Oak Forest.. ...... Garards Fort.. .... Masontown. ........ Degrees separation 

Directional mean.. 

County separation.. . Countvmean ......... 

MARION AND MONONGALIA COUNTIES . 

Degrees separation 

Direction mean.. ... County separation.. . 

GREEN 

N 24" E 

N 22" E 

N 20" E 

- N 18" E 

6 

N 21" E 

- N 17" E 

N 17" E 

N 23" E 

- 

6 

N 19" E 

2" 

N 20" E 

N 3" E 

N 3" E 

N 3" E 

N 8" E 

- 

5 

N 4" E 

N 5" E 

N 5" E - 

- 

- 

0 

_N 5" E 

1" 

N5" E 

Tier 7: 

Glover Gap. ....... Manning ton. ....... Grant Town.. ...... Rivesville.. ...... Morgantown South.. 

Degrees separation 

Directional mean.. 

- 

- 

1" 

4 

N 6" E 

WETZEL AND MONONGALIA COUNTIES 

Tier 6: 

Hundred, .......... Wadestown. ........ Blacksville. ...... Osage.. ........... Morgantown North. . Degrees separation 

Directional mean., 

- 

- 

- 

N 3" E - 

- 

N 3" E 

3 

N 20" E 

3" 

COUNTY 

- 

- 

- 

- 

- 

- 

- 

N 35" E 

N 33" E 

N 27" E - 

N 30" E 

8 

N 31" E 

- 

N31° E 

MARION AND HARRISON COUNTIES 

N 50" E - 

- 

N 44" E 

N 48" E 

6 

N 47" E 

- 

- 

- 

N 41" E 

- 

- 

N 41" E 

6" 

N44" E 

- 

- 

- 

N 2" E 

- 

- 

N 2" E 

N 17" E - 

- 

- 

N 12" E 

5 

N 15" E 

Tier 8 : 

Wallace. .......... Shinnston.. ....... Fairmont West.. ... Fairmont East...., 

Gladesville.. ..... Degrees separation 

Directional mean.. 

4 

N 37" E 

1" 

N 89" E - 

- 

- 

- 

- 

N 89" E 

- 

- 

- 

- 

N 88" E 

- 

N 88" E 

1" 

N89" E 

- 

- 

N 62" E 

N 63" E 

- 

1 

N 63" E 

- 

- 

- N 60" E 

- 

- 

N 60" E 

3" 

N62" E 

- 

N 48" E 

5" 

N 73" E - 

- 

N 78" E 

N 79" E 

6 

N 77" E 

N 70" E 

- 

N 75" E 

N 73" E 

N 75" E 

9 

N 73" E 

4" 

N 75" E 

N 17" E 

N 13" E - 

- N 15" E 

4 

N 15" E 

- 

N 27" E 

N 26" E 

- 

N 22" E 

5 

N 25" E 

- 

- 

- 

- 

- 

- 

- 

- 

- 

N 24" E 

- 

- 

- 

N 24" E 

- 

- 

- N 41" E 

N 33" E 

8 

N 37" E 

N 18" E - 

- 

- 

N 13" E - 

N 16" E 

- 

- 

- 

N34" E 

N 30" E 

4 

N 32" E 

- 

- 

- 

- 

- 

- 

- 

- 

N 26" E 

N 23" E 

N 22" E 

- 

4 

N 24" E 

N 58" E 

N 49" E - 

N55" E - 

9 

N 54" E 

N 64" E 

- 

- 

N 75" E 

N 67" E 

11 

N 69" E 

N 33" E 

- 

- 

N 41" E 

N 40" E 

8 

N 38" E 

- 

- 

- 

- 

- 

- 

- 

N 68" E 

N 74" E - 

N 73" E 

- 

6 

N 72" E 

- 

- 

N 50" E - 

- 

- 

N 50" E 

- 

- 

N 87" E - 

N 89" E - 

N 88" E 

N 63" E - 

- 

- 

- 

- 

N 63" E 

- 

- 

- N 83" E 

N 85" E 

2 

N 84" E 
APPENDIX D. --PRINCIPAL DIRECTION FOR INDIVIDUAL PHOTOINDEX 

SHEETS OF THE STUDY AREA 

IN T.mBU.0 F MINES, PGH.%P A. 2070 1 

West 

1 I 2 I 3 I 4 

East 

1 I 2 I 3 I 4 

WASHINGTON COUNTY 

N 72" E 

N 74" E 

N 70" E 

N 77" E 

N 73" E 

7 

N 73" E 

Sheet : 

1.. . . . .. . . . Z.... ...... 3.. . . . . ... . 4.. . .. . . . . . 5.. . ....... Degrees 

separation.. 

Direct ional 

mean. .. . ... . GREENE COUNTY 

N 51" E 

N 52" E 

N 49" E 

N 50" E 

N 53" E 

4 

N 51" E 

N 45" W 

N 43" W 

N 44" W 

N 45" W 

N 47" W 

4 

N 45" W 

N 23" E 

N 23" E 

N 18" E 

N 17" E 

N 12" E 

11 

N 19" W 

N 67" W 

N 67" W 

N 68" W 

N 70" W 

N 77" W 

10 

N 70" W 

N 7" W 

N 10" W 

N 13" W 

N 9" W 

N 10" W 

6 

N 10" W 

N 30" E 

N 32" E 

N 27" E 

N 34" E 

N 27" E 

7 

N 30" E 

N 19" W 

N 24" W 

N 20" W 

N 28" W 

N 27" W 

9 

N 24" W 

Sheet: 

I... ... . . . . 2.. . . . . . . . . 3 ..... . .. . . 4.......... 

Degrees 

separation.. 

Directional 

N 14" E 

N 10" E 

N 7" E 

N 12" E 

7 

N 7" W 

N 12" W 

N 9" W 

N 5" W 

7 

N 79" E 

N 58" E 

N 56" E 

N 57" E 

N 53" E 

5 

N 68" W 

N 70° W 

N 70" W 

N 67" W 

3 

N 28" E 

N 24" E 

N 21" E 

N 26" E 

7 

N 25" W 

N 23" W 

N 20" W 

N 23" W 

5 

N 81" E 

N 75" E 

N 77" E 

N 82" E 

7 

N 47" W 

N 43" W 

N 42" W 

N 44" W 

5 

mean. .. .... . N 8" W 

MONONGALIA COUNTY 

N 23" W N 42" W N 69" WIN 11" E 

Sheet : 

1. .. ....... 2.. . .. .... . Degrees 

separation.. 

Directional 

mean.. . . . . . . 

N 25" EIN 56" E 

N 20" W 

N 23" W 

3 

N 22" W 

N 8" W 

N 7" W 

1 

N 8" W 

MARION COUNTY 

N 42" W 

N 43" W 

1 

N 43" W 

Sheet: 

1. .. . .... . . z*......... 

Degrees 

separation.. 

Directional 

mean.. . ..... 

N 69" W 

N 70" W 

1 

N 70" W 

N 8" W 

N 7" W 

1 

N 8" W 

OVERALL 

N 5" E 

N 10" E 

5 

N 8" E 

Degrees 

separation 

between 

counties.... 

Directional 

mean.. .. .. .. 

N 28" W 

N 20" W 

8 

N 24" WIN 

N 19" E 

N 26" E 

7 

N 23" E 

N 42" W 

N 44" W 

2 

43" W 

N 72" W 

N 73" W 

1 

N 73" W 

2 

N 9" W 

N 60" E 

N 56" E 

4 

N 58" E 

N 4" E 

N 7" E 

3 

N 6" E 

2 

N 23" W 

N 79" E 

N 81" E 

2 

N 80" E 

N 19" E 

N 21" E 

2 

N 20" E 

2 

N 44" W 

N 57" E 

N 59" E 

2 

N 58" E 

3 

N 70" W 

N 78" E 

N 77" E 

1 

N 78" E 

13 

N 12" E 

10 

N 27" E 

7 

N 55" E 

7 

N 77" E