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

BUREAU OF MINES 
CONTENTS 

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

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

Instrumentation ....................................................... 4 

Methane emissions and coal production .................................. 5 

Methane emissions and overburden ....................................... 10 

Methane emission and virgin ribs ....................................... 11 

Methane emissions during 32-day strike ................................. 13 

Methane layering in Beckley mine ....................................... 14 

Conclusions. ........................................................... 15 

Recommendations ........................................................ 15 

References ............................................................. 16 

ILLUSTRATIONS 

Structure of Beckley coalbed ...................................... Structure of base of Beckley coalbed at the Beckley mine .......... Mine outline ...................................................... Daily methane emissions and coal production from North mains ...... Daily methane emissions and coal production from Northwest mains .. Daily methane emissions and coal production from South mains ...... Daily methane emissions and coal production from South right mains 

Overburden over Beckley mine development .......................... Daily methane emissions from monitored sections during strike ..... Daily barometric pressures from weather station at Beckley. W . Va . Daily methane emissions from three sensors in layering experiment .. 

TABLES 

1 . Range of daily coal production and daily methane emissions ........ 6 

2 . Summary of monthly methane emissions and coal production .......... 10 

3 . Summary of methane emissions and overburden thicknesses ........... 10 

4 . Virgin rib lengths ................................................ 12 
METHANE EMISSIONS FROM FOUR WORKING PLACES 

IN THE BECKLEY MINE, RALEIGH COUNTY, W. VA. 

by 

Pa W. Jeran, D. Ha Lawhead,2 and Ma C. Irani 

AB STRACT 

The Beckley mine is one of five new mines in a heretofore unmined portion 

of the Beckley coalbed. The remoteness of these new mines from prior mining 

and their greater overburden preclude applying methane emission experience 

obtainedinthe oldmines. Four sections ofthe Beckleyminewere monitored. The 

data gathered show that variations in methane emission cannot be explained by 

variations in coal production. Although overburdens varied by as much as 

30 pct, no correlation with methane emissions could be determined. The rib 

emissions increase with increased length of rib from a section advancing into 

virgin coal and do not decline over a prolonged idle period (32 days) whereas 

some decline has been measured for a section not mining into virgin coal. The 

indication is that degasification prior to mining will reduce the hazard of 

methane emissions in this area of the Beckley coalbed. 

INTRODUCTION 

Methane air explosions are a major hazard in underground coal mining. 

The Bureau of Mines has developed two instruments that give continuous and 

accurate data on the emission of methane into coal mines. One, an exhaust fan 

4 methanometer (z), monitors total emissions from the mine. The other, an 

in-mine methane analyzer system (L), allows subdivision of the total variations seen at the exhaust fan into the component parts contributed by the individual sections of the mine. 

The first multiple section installation of the methane analyzer system 

was at the new Beckley mine operating in the Beckley coalbed near Glen Daniel, 

Raleigh County, W. Va. The mine property is in an area of the Beckley coalbed 

Geologist. 

 i in in^ engineering technician. 3 Supervisory mining engineer. 

All authors are with the Pittsburgh Mining and Safety Research Center, 

Pittsburgh, Pa. 

4 Underlined numbers in parentheses refer to the list of references at the end 

of this report. 
remote from prior mining. Four other mines in this area of the coalbed are in 

various stages of planning and development. 

The remoteness from prior mining does not permit the extrapolation of 

methane emission data from the old mines to these new mines. The primary 

purpose of this investigation was to study the effects of various parameters 

on methane emissions during mining. 

Monitoring began September 12, 1974, and was continued until December 27, 

1974, when an icefall in the main shaft severed the data cable connecting surface and underground components of the instrumentation system. 

The geology of the Beckley coalbed was described byPopp andMcCulloch (5). - Past mining in the Beckley coalbed shows that it varies in thickness. Popp 

and l~lcCulloch show the coalbed to range from less than 36 to 108 inches within 

the Beckley mine property. In these workings the coalbed is about 7 feet 

thick. 

The Beckley coalbed dips to the northwest and has two major folds, the 

Pineville anticline and syncline (fig. l), neither of which are present in the 

Beckley mine property. Overburden above the Beckley coalbed ranges from200 to 

over 2,200 feet, but at the Beckley mine the average overburden thickness is 

830 feet (5). 

The face cleat in the Beckley mine is oriented about 15" counterclockwise from a major rock joint striking N 25" W. The butt cleat oriented 

N 50" E lies between the two strongest or most often measured rock joints. 

The cleat, although well developed, is not closely related to the jointing of 

the rocks overlying the coalbed. 

Little geologic variation was observed in the Beckley mine. The roof 

rock is gray sandy shale between 30 to 40 feet thick. The floor rock is dark 

shale. A contour map of the base of the Beckley coalbed within the mine 

(fig. 2) shows that the coal dips to the northwest, in general agreement with 

the regional structure of the coalbed. No variations in the coal cleat 

orientation were observed within the mine workings. 
WYOMING COUNTY 

I I 

McG RAWS LESTER CRAB ORCHARD 

1 

L 

FIGURE 1. - Structure of Beckley coalbed. 
The methane analyzer system (L) installed in the Beckley mine has a 

capacity for 31 methane sensors because of the size of the data transmission 

cable. The system continuously records the volume percent of methane in the 

air passing each sensor with an accuracy of '0.04 on a scale of 0 to 2 vol-pct. 

The receiving units and recorders at the surface were connected to the 

sensors through the main data cable containing 31 pairs of wire. The cable 

ran down the elevator shaft to an underground electrical room where the power 

supply boxes were installed. From these boxes, four-conductor cables were 

strung to each sensor. 

A standby battery power source at the surface receiving station insures 

continuous methane recordings in case of a power failure on the surface. Up 

to 3 hours of electrical power can be supplied to the receiving units and 

recorders in this way. Also, each sensor contains a standby battery. 

The four sections monitored were the North mains, Northwest mains, South 

mains, and the South right mains (fig. 3). The Southwest mains was not monitored because changes were being made in ventilation to this area. 
Sensors were installed at each of the regulators controlling airflow 

from the individual sections. The volume of air passing each regulator is 

regularly measured by mine personnel. The ventilation and daily coal production data from each section were supplied by the mining company. 

METHANE EMISSIONS AND COAL PRODUCTION 

Figures 4-7 are plots of the daily methane emissions and coal production from each section. The breaks in the coal production represent periods 

of idle time. The dashed line is a 32-day strike. 

These graphs show the wide range of daily coal production and give 

the general trend of methane emissions during the monitoring. Only the South 

mains (fig. 6) shows a definite upward trend in methane emission. Table 1 

summarizes the range and average values of daily coal production and daily 

methane emission. These data show that while the north sections had the same 

range of daily coal production as the south sections, the north sections were 

not as productive of either coal or methane. 
Ill I IIIII I I I I I I1 1 1 I 

- 

- 

- - 

- - 

- - 

Ill I I IIII I I Ill Ill I I I 

September 30 October 3 1 November 30 December 3 1 

1974 

TIME, months 

FIGURE 4. - Daily methane emissions and coal production from North mains. 

TABLE 1. - Range of daily coal production and daily methane emissions 

No. of 

Sect ion I monitored Days i production, 

1 Daily average. 

North ............... 

Northwest. .......... 

South ............... 

South right ......... 

Range of coal 

production, 

Range of methane 

emissions, ft3 

107 

107 

107 

86 

days 

43 

47 

55 

41 

tons 

60 to 500 

'282 

50 to 400 

I224 

50 to 500 

'361 

50 to 500 ' 356 

180,000 to 380,000 

1289,000 

80,000 to 200,000 

135,000 

180,000 to 450,000 ' 304,000 

120,000 to 250,000 ' 158,000 

Ill Ill I I I I\' I I 1 

I 

- I I 

I I 

- 

- I- Strike - 

- 

I /I I - 

L 

- 

- 

- - 

. 1 I IIIII I Ill Ill Ill Ill 

0 September 30 October 3 1 November 30 December 

1974 

TIME, months 

FIGURE 6. - Gaily methane emissions and coal ~roduction from South mains. 
wv, 

z 

0 

J - 100 v, 

Ill I"" I I I -11 I I I I ' 1' I I I 

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I 

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: dJ/\[[(y\~rstrike [ ; - -

- 

- 

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111 I I I I I I I 111 111 I I I b 0 

September 30 October 3 1 November 30 December 3 1 

1974 

TIME, months 

FIGURE 7. - Doily methane emissions and cool production from South right mains. 

The South mains section had the highest average coal production and also 

the highest methane emissions. Its companion section, South right mains, had 

almost as high an average daily coal production but only about half the emissions. This same relationship exists between the North and Northwest mains. 

Comparison of the monthly totals of coal production and methane emissions for 

each section monitored (table 2) shows no correlation between volume of methane emitted and tons of coal produced within each section. Furthermore the 

plots of the daily methane emissions and daily coal production show no correlation between daily high coal production and high methane emission. 
TABLE 2. - Summary of monthly methane emission and coal production 

'NO data. 

METHANE EMISSIONS AND OVERBURDEN 

Total methane, 

October to 

December, ft3 

24.44 xlOG 

12.39 x106 

29.75~10q 

13.6 x106 

Except for North mains, all sections increased their average daily 

methane emission during the monitoring (table 3). During this time the overburden (fig. 8) above the face increased for all except Northwest mains. The 

two southsections showan increase of methane emission with increased overburden while the two north sections contradict this. Therefore, no conclusions from these data can be drawn regarding the effect of overburden on 

methane emissions in this area. 

Section 

North: 

September ......... October... ........ November .......... December... ....... Northwest: 

September ......... October ........... November .......... December .......... South: 

TABLE 3. - Summary of methane emissions and overburden thicknesses 

Total methane 

for month, ft3 

6.49~10~ 

8.37 x10" 

8.32x106 

7 .75x106 

2.13~10' 

3.65 x10' 

4.35 x106 

4.39~10' 

4. 53x10G 

8.85x106 

10.60 x106 

10.30 x106 

4.52~10" 

5.17 ~10" 

3.92~10~ 

Total coal 

for month, 

tons 

564 

6,776 

1,696 

3,092 

7 50 

7,717 

1,034 

1,014 

Total coal, 

October to 

December, tons 

11,564 

9,765 

17,178 

14,7 65 

September ......... 1 2,661 

October. .......... November .......... December .......... South right: 

September ......... October ........... November .......... December .......... 

Sect ion 

South mains.... ....... North mains.......... . Northwest mains. ...... South right mains.. ... 

11,802 

2,214 

3,162 

10,536 

2,201 

2,028 

Average overburden over 

face, ft 

Average daily emissions, ft3 

Beginning 

6 50 

650 

650 

7 50 - 

Beginning 

200,000 

350,000 

100,000 

150,000 

Ending 

850 

700 

625 

850 

Ending 

400,000 

350,000 

150,000 

200,000 
e oute at stat ootog 0 50 300 

---- Mine outline at end of monitorinq 

'850,~ontour interials, 50ft 

Scale 

FIGURE 8. - Overburden over Beckley mine development. 

METHANE EMISSIONS AND VIRGIN RIBS 

At the beginning of the monitoring the North mains had advanced about 

1,250 feet beyond the initial development and the South mains had advanced 

about 1,000 feet. At the end of the monitoring period the North mains had 

advanced to 1,550 feet and the South mains had advanced to 1,600 feet. The 

limited advance (300 feet) of the North mains was due to roof control problems. 

The 250-foot difference in advance into virgin coal at the beginning of monitoring is reflected in a 150,000-ft3/d difference in daily methane emissions. 

At the end of monitoring the 50-foot difference in advance is reflected in a 

50,000-ft3/d difference in emissions. This shows that the section furthest 

advanced into virgin coal has the highest emissions in both cases. 

The virgin rib lengths of each section at the beginning and end of 

monitoring are summarized in table 4. Tables 3and 4 show that the South mains 

doubled average daily emissions after a 690-foot increase in rib length while 

the North mains showed no increase in methane emissions with a 320-foot 

increase in rib length. The South mains had fairly regular production and 

steady advance and the methane emissions rose accordingly. The North mains, 

with sporadic production and irregular advance, showed no increase in daily 

methane emissions. This indicates that a steadily advancing section in the 

Beckley coalbed will exhibit increasing methane emissions. 
TABLE 4. - Virgin rib lengths, feet 

The South right mains and Northwest mains both showed increased methane 

emissions of 50,000 ft3/d with virgin rib increases of 320 feet. Comparing 

the South right mains and Northwest mains, almost equal initial rib lengths, 

increases in rib lengths, and increases in daily methane emissions are noted. 

Throughout the study interval the South right mains had 50,000 ft3/d more 

daily methane emission than the Northwest mains. The 50,000-ft3/d difference 

in methane emissions between these sections is attributed to the relative 

distances behind their adjacent sections. The Northwest mains, 500 feet 

behind North mains, mined into a more degasified area of the Beckley coalbed 

than did the South right mains, which started only 100 feet behind the South 

mains. 

The four sections monitored can be grouped into two sets of 10 entries, 

one driving north, and the other south. Each of these consists of two 5-entry 

sections in which one section is advancing into virgin coal and the other is 

following between 100 and 500 feet behind. Krickovic, Findlay, and 

Merritts (4) found that comparing two working places in the Pittsburgh coalbed, 

one adjacent to old workings, produced 32 ft3/min less methane for twice as 

much coal as one mining into virgin coal. In the Beckley coalbed the data 

show that the following section, mining coal partially degasified by the 

advance section, has about half the emissions of the advancing section. 

Sect ion Start of monitoring End of monitoring 

2,380 

1,290 

2,920 

1,200 

North mains........... ...... Northwest mains.. ........... South mains...... ........... South right mains........... 

Increase 

320 

320 

690 

320 

2,060 

97 0 

2,230 

880 
I 

- Northwest mains - 

- 

- 

8 

- South right mains - 

- 

- 

.l 

- 

- 

- South mains - 

A 

- - 

- 

- 

North mains 

METHANE EMISSIONS DURING 32-DAY STRIKE 

A 32-day strike took place at the 

Beckley mine during the 107-day monitoring period. Methane emission was 

monitored continually for all four 

sections during this idle time 

(fig. 9). The graphs show that the 

North mains and the South mains, both 

driving into virgin coal, had no 

decline in emissions during the strike. 

The Northwest mains and the Southwest 

mains driving parallel to, but behind 

the North and South mains, had lower 

gas emissions with a slight decline 

except for a slight peak at the end. 

This indicates that methane emissions 

from the r i b s w i l l be long lasting and 

that advance degasification can effectively control emissions into the 

return airways. The slight decline in 

the following sections indicates that 

rib emissions do decline but data are 

insufficient to estimate the rate of 

decay. 

Jeran (3) reported that in the 

Pittsburgh coalbed the methane emissions from an advancing section can be 

explained by the length of virgin rib. 

The data gathered during this monitoring, while not sufficient to demonstrate the excellent correlation 

previously observed, show that in the 

Beckley coalbed methane emissions 

increase with increased length of 

FIGURE 9, - Daily methane emissions from virgin rib. 

monitored sections during During the 32-day strike, the 

strike, daily methane emissions were not 

constant or regular. These variations 

are not explained by the daily barometric pressure variations (fig. 10); the 

largest barometric change of 0.7 inch mercury (November 30 through December 4) 

had no effect on methane emission from any section. The variations in daily 

methane emissions observed during idle time remain unexplained. 
airway, approximately 140 feet from the active face. One sensor was 15 

inches below the roof, another 15 inches above the floor, and the third midway between, 3 feet from the floor. 

W .- 27.75 

w 

11 

m 27.50 m 

W 

27.25 

oCK O .C 27.00 

W 

z 

O 26.75 CK 

a * 26.50 

Recordings taken from the sensors for 30 days while the section was 

advancing show that the methane was well mixed in the return air by the time 

it reached the sensors. At no time during the experiment did the methane concentration exceed 0.35 pct methane (fig. 11). 

C 0.40~1111~1111~1111 ,"ll,l,,l,'lll ,,Ill 

w U, - 

- 

> a 

A .I - ---Middle sensor 

z + 

- 

n W -Bottom sensor 

2 

02~11~1'1111"1~1111~"~29 1 3 8 13 18 23 28 

emissions were increasing 

FIGURE 10. - Dai ly barometric pressures from weather steadily. Three methane 

station at Beckle~, We Va. sensors were placed in the 

center of the left return 

1 I 

- - 

- - 

- 

I - 

I 

I I - I - I Strike period 

I I 

METHANE LAYERING IN 

B ECKLEY MIN E 

During the monitoring 

period, an experiment was 

set up to determine if 

methane emitted from an 

active section was layering 

in the return airway. The 

South mains were chosen for 

this experiment because mining was fairly rapid and gas 

FIGURE 11. - Daily methane emissions from three sensors in layering experiment. 

t~ctober --- ~overnberd 

1974 

TIME, days 
CONCLUSIONS 

The 107-day monitoring of the four sections in the Beckley mine showed 

that the coal production rate cannot be used as a parameter to explain methane 

emission; that sections advancing steadily into the virgin Beckley coalbed 

will have increasing methane emissions; that the driving of a section into 

virgin coal partially degasifies the coal resulting in lower emissions from a 

following parallel section; and that rib emissions from the Beckley coalbed 

are slow to decline and not affected by normal barometric pressure variations 

(0.7 inch of mercury) . 

RECOMMENDATIONS 

This study is the first long-period monitoring of methane emissions from 

the Beckley coalbed in a heretofore unmined area. Based upon the data gathered, it is recommended that companies planning new mining in this area seriously consider some technique of degasification of the coalbed in advance of 

mining to decrease and control the level of methane emission into mine 

workings. 
REFERENCES 

1. Irani, M. C., P. W. Jeran, and D. H. Lawhead. Methane Analyzer System To 

Record Continuously the Methane Content of Coal Mine Ventilation Air. 

BuMines RI 8009, 1975, 14 pp. 

2. Irani, M. C., A. Tall, B. M. Bench, and P. W. Jeran. A ContinuousRecording Methanometer for Exhaust Fan Monitoring. BuMines RI 7951, 

1974, 18 pp. 

3. Jeran, P. W., D. H. Lawhead, and M. C. Irani. Methane Emissions From an 

Advancing Coal Mine Section in the Pittsburgh Coalbed. BuMines RI 8132, 

1976, 10 pp. 

4. Krickovic, S., C. Findlay, and W. M. Merritts. Methane Emission Rate 

Studies in a Northern West Virginia Mine. BuMines TPR 28, 1970, 11 pp. 

5. Popp, J. T., and C. M. McCulloch. Geological Factors Affecting Methane in 

the Beckley Coalbed. BuMines RI 8137, 1976, 35 pp. 

r': U.S. GOVERNMENT PRINTING OFFICE: 1977-703-001 i34