By A. T. lannacchione, G. L. Finfinger, 

T. M. Kohler, and D. M. Hyman 

UNITED STATES DEPARTMENT OF THE INTERIOR 
Report of Investigations 8723 

Investigation of Methane Emissions 

From an Advancing Face in the Belle 

Isle Domal Salt Mine, Louisiana 

By A. T. lannacchione, G. L. Finfinger, 

T. M. Kohler, and D. M. Hyman 

UNITED STATES DEPARTMENT OF THE INTERIOR 

James G. Watt, Secretary 

BUREAU OF MINES 

Robert C. Horton, Director 
This publication has been cataloged as follows: 

r 

In~esti~atiorl of methane emissions from an advar~cing fat-c. in tllc t3ellc. 

Isle tiomal s;llt mine, 1,ouisiana. 

(Report of investigatioris ; 87'23) 

tli bIiography: p. 15. 

Supt of 1)ocs. no.: I 28,21:8-23. 

1. Salt mines arltl mining-1.ouisiana-Ilellc Isle (Saint hlary Parish)- 

Safety rneasurcs. 2. Methane-I.ouisiana-HeIIc Isle (Saint Mary 1';lrish)- 

Measureme~lt. 3. Mine gascs-l.ouisianil-13elle Isltx (Saint Mary L'arishlXleasuremcnt. I. lnnnacchiorle, Anthony 7'. 11. Scrics: Kcport of invcstigations (1'nitc.d States. Hurcau of Mines) ; 8-25. 

'I'N 23,U/13 r'l'N90 2,I.X) 2 2 82-600255 
CONTENTS 

Page 

Abstract ....................................................................... Introduction ................................................................... Acknowledgments ................................................................ Engineering and geological setting ............................................. Location of study area .................................................... Design and layout of sensing system ....................................... Geology of the advancing face ............................................. Methane emissions from the advancing face ...................................... Methane concentrations .................................................... Velocity determination .................................................... Methane emission rates .................................................... Exploratory drilling of advancing face .................................... Summary and conclusions ........eee.............e.ee...ee.......e.eee.......ee.. 

References ..................................................................... Appendix.--Strip-chart data of methane sensor and sonic anemometer inside exhaust duct during the 18 production days used to calculate methane concentrations. production times. and emission rates .................................. ILLUSTRATIONS 

Location of study area within decline of Belle Isle salt mine. Louisiana 

Cross-sectional view of the locations of the instruments used to monitor 

velocity and methane concentrations from advancing decline face ....... Photograph showing the intake methane sensor. 30-in exhaust duct. transformer. and control system ............................................ Photograph showing the placement of the sonic anemometer and methane 

sensor in exhaust tubing .............................................. A plan view of mappable geological units encountered within the lower 

portion of the decline and location of the advancing face during the 

18 production days of this investigation .............................. Trace of dark. argillaceous salt zone (anomalous zone) within the Belle 

Isle salt dome ........................................................ Photograph of the dark. argillaceous salt occurring in the study area ... Temperature and barometric pressure measurements recorded in the decline 

during the investigation .............................................. Daily range of methane emissions from the advancing decline ............. Methane emission rates from advancing decline using production time for 

rate estimates ........................................................ Methane emission rates from advancing decline using tons of salt hauled 

for rate estimates . Tonnage data was supplied by the operator ........ A comparison of tonnage (salt hauled) with production time (measured 

from charts) enables calculation of decline production rate ........... Corrected methane emission rates for each of the 18 production days ..... Strip-chart recording of methane emissions during drilling of an exploratory drill hole ...................................................... A.1 . Day 1 ................................................................... A-2 . Day 2 ................................................................... A.3 . Day 3 ...........................................e.eeee............e.ee.. 

A-4 . Day 4 ................................................................... A-5 . Day 5 ................................................................... A-6 . Day 6 ................................................................... A.7 . Day 7 ................................................................... 
ILLUSTRATIONS.. Continued 

Page 

A.8 . Day 8 .................................................................. 19 

A-9 . Day 9 .................................................................. 20 

A-10 . Day 10 ................................................................. 20 

A-11 . Day 11 ................................................................. 21 

A-12 . Day 12 ................................................................. 21 

A-13 . Day 13 ................................................................. 22 

A-14 . Day 14 .................................................................. 22 

A-15 . Day 15 ................................................................. 23 

A-16 . Day 16 .................................................................. 23 

A-17 . Day 17 ................................................................. 24 

A-18 . Day 18 ................................................................. 24 

TABLES 

1 . Gas analysis from face area collected several days after the last production shift ......................................................... 8 

2 . Gas analysis from face area collected immediately after a production 

shift .........e....................................................... 8 

3 . Gas analysis from face area collected after the drilling of several exploratory drill holes ................................................. 9 

4 . Air velocity and quantity ranges within exhaust tubing for varying air 

densities ............................................................ 10 

5 . Gas analysis taken approximately 1-ft (0.3 m) inside the collar of a 

300-ft (91-m) exploratory drill hole .................................. 15 

LIST OF ABBREVIATIONS 

cm centimeter mi mile 

f t foot min minute 

g grams Pet percent 

hr hour t metric ton 

km kilometer ton short ton 

m meter wt-pct weight-percent 
INVESTIGATION OF METHANE EMISSIONS FROM AN ADVANCING FACE 

IN THE BELLE ISLE DOMAL SALT MINE, LOUISIANA 

By A. T. lannacchione, G. L. Finfinger, 2 T. M. Kohler, 3 and D. M. Hyman 1 

ABSTRACT 

The Bureau of Mines measured methane emission rates from an advancing 

salt face ranging from 15 to 56 ft3/ton (0.5 to 1.8 m3/t). Small room 

size, use of a continuous miner, and a well-defined ventilation system 

made possible air velocity and methane concentration measurements, 

These measurements, representing data from 18 production days, were conducted in an area of abnormally low grade salt, Methane emissions 

occurred primarily during the advance of the salt face by continuous 

miner. 

l~eologist. 

2~upervisory geologist . 3~ining engineer. 

All authors are with the Pittsburgh Research Center, Bureau of Mines, Pittsburgh, Pa. 
INTRODUCTION 

Since 1979 four of the Five Islands 

salt mines in southern Louisiana have 

been classified as "gassy" mines. Compliance with Part 57, Title 30 of the 

Code of Federal Regulations is presently 

being investigated to determine its 

influence on mining productivity. Basic 

information on methane emission rates, 

physical properties tests, and methane 

content of domal salt mines is needed to 

develop the safest and most economical 

way to control methane. 

Bureau of Mines research is currently 

divided into three tasks: 

1. Characterizing the quality, composition, and occurrence of potentially 

explosive gases with rapid changes in 

the geology and geochemistry of domal 

salt. 

2. Determining the physical properties 

of domal salt, such as pressure gradients, permeability, and gas flow characteristics. This information will determine the potentials of directional 

in-mine drilling technology for degassing 

and/or avoiding outburst-prone areas. 

Outbursts , which occur in several Louisiana salt mines, are a sudden, violent 

release of occluded gases and salt under 

high pressure (7) - .4 

3. Examining daily methane emissions 

from advancing faces to identify correlations with changes in production rates, 

atmospheric conditions, and geology of 

the advancing face. Characterization of 

the most important factors affecting 

methane emissions from working faces can 

then be made so that a safe mining method 

can be established. 

ACKNOWLEDGMENTS 

The authors wish to thank all of the 

operators and miners of the Five Islands 

salt mines of southern Louisiana for 

their help and cooperation. Special 

thanks are extended to Charles von 

Dreusche and Thomas Fudge of Cargill, 

Inc. (Belle Isle Mine) for helping 

locate a site for this investigation. 

J. D. Martinez, R. L. Thoms, and D. H. 

Kupfer of Louisiana State University 

provided valuable information on geological and engineering problems encountered 

in mining domal salt. Invaluable technical support was supplied by R. Wosniak of 

Ryan Laboratories, MSA Corp., Pittsburgh, 

Pa., in instrumentation design and V. G. 

Iannacchione of the Research Triangle 

Institute, Research Triangle Park, N.C., 

in statistical analysis. 

ENGINEERING AND GEOLOGICAL SETTING 

Location of Study Area 

The Belle Isle mine, one of a group of 

four underground domal salt mines presently operating in southern Louisiana, is 

located 19 mi (30.6 km) southeast of 

Franklin, La. Within this mine a decline 

is being driven from the 1,200-ft (366-m) 

level to the 1,600-ft (488-m) level 

(fig 1) . The advancing face of this 

decline, which is being worked by a continuous miner, is 13 ft (4 m) high by 

35 ft (11 m) wide. Normal production 

faces in domal salt mines are 30 ft (9 m) 

high by 60 to 160 ft (18 to 40 m) wide 

and are advanced by blasting 5- to 15 f t 

(2- to 5-m) cuts into the face. The 

advancing decline is ideal for a methane 

emissions study because of the comparatively small room size, presence of a 

rigid exhaust duct, and use of a continuous miner. 

lunderlined numbers in parentheses refer to items in the list of references 

preceding the appendix. 
g 

of Belle Isle salt mine, Louisiana. steel to prevent corrosion. The sonic 

Methane sensor and sonic anemometer 

(installed within exhaust duct) 

SCALE LEGEND 

- -- Intake air Exhaust air 

Advancing 

face 

FIGURE 2. - Cross-sectional view of the locations of the instruments used to monitor velocity and 

methane concentrations from advancing decline face. 
FIGURE 4. - Photograph showing the la cement of the sonic anemometer and methane sensor in 

exhaust tubing. 
anemometer, which employs the vortex 

shedding principle, measures velocities 

ranging from 1,500 to 10,000 ft/min (457 

to 3,048 m/min) and is unaffected by air 

density changes. The sonic anemometer 

head and one of the methane sensor heads 

were placed directly into the exhaust 

tubing (fig. 4). Another methane sensor 

was placed directly into the intake air 

stream. A third methane sensor sampling 

air from the exhaust tubing did not operate during the preliminary investigation 

because of mechanical problems with the 

vacuum pump. 

Geology of the Advancing Face 

Three mappable geological units are 

represented in the study area (fig. 5). 

The upper or southern portion of the 

decline is predominantly a clean or 

normal production grade salt with occasional dark bands that are generally 

diffuse in density and light gray in 

color. The strike of these bands range 

from N 0' N to N 50' W in the upper or 

southern half of the decline. The second 

distinct mappable unit (fig. 5) has 

tightly folded darker bands that are 

b~ethane sensors 

////////////7////////////3/ // / / 

3-30 4-8 4-20 4-24 

3-31 Approximate location per day of 

advancing face (month-day ) 

a Location of rock salt samples 

White salt with occasional \\ darkbands 

\ Dark argillaceous salt, 

h \ highly banded 

0 * 20 40 60 Ft 

0 6 12 18 M 

SCALE 

FIGURE 5. - A plan view of mappable geological units encountered within the lower portion of 

the decline and location of the advancing face during the 18 production days of 

this investigation. 
the dissolution method (2). The sample contained approximately 2.2 cm3 

CH4 per 100g (0.7 ft3/ton) of salt, 

0.3 cm3 CO per 100 g (0.1 ft3/ton), and 

had a water-insoluble residue of approximately 9 wt-pct. Gas-enriched salt from 

the Five Islands salt domes have occluded 

methane contents ranging from about 

0.2 to 10 cm3 per 100 g of salt (2). The 

salt sampled from the study area popped 

and snapped when broken and/or dissolved 

similar to gas-enriched "popping" salt. 

Decline 

FIGURE 6. - Traceof dark, argillaceous salt zone 

(anomalous zone) within the Belle Isle salt dome. 

associated with the trace of a largescale, anomalous zone mapped elsewhere in 

the dome. It is a low-grade production 

quality salt. The occluded methane content of this anomalous salt is somewhat 

less than that of salt samples collected 

from areas where outbursts have 

occurred. 

The salt encountered in the study area 

is essentially a dark, argillaceous salt 

METHANE EMISSIONS FROM THE ADVANCING FACE 

Methane was found to be emitted from a mined at this face emits a measurable 

freshly mined underground salt face as amount of methane, comparisons are made 

well as from the broken salt being ex- based on the relative volumes of gas 

tracted from the face. Because the salt emitted per unit weight of mined salt. 
FIGURE 7. - Photograph of the dark, argillaceous salt occurring in the study area. 

The methane emissions study covered in 

this study report spanned 18 production 

days and several days of exploratory 

drilling of the face from March 30 to May 

15, 1981. The methane emitted per ton of 

salt mined ranged from approximately 

15 to 56 ft3/ton (0.5 to 1.8 m3/t). Four 

interesting points have been noted during 

this study: 

1. Methane emissions occur mainly during mining. 

2. Methane concentrations are very low 

during nonmining periods. 

3. Methane concentrations decline to 

very low rates in about 1 to 4 hr after 

salt production. 

4. Some variation in methane emission 

rates occurs during mining. 

Methane Concentrations 

Methane emissions were measured by 

recording methane concentrations with 

the sensor units. Methane was found 

to range from 0 to 0.2 pct inside 

the exhaust duct (see appendix). No 

measurable amount of methane was detected 

from the methane sensor in the intake 

air. 

Gas samples from the face area collected in evacuated 20-1 glass cylinders 

were analyze in the laboratory to confirm the accuracy of the methane sensors. 

Samples were collected, approximately 

1 ft (0.3 m) from the advancing face on 

March 28, March 30, and May 15, 1981. 

Analysis from table 1 were taken on a 

weekend several days after the last 

production shift. Table 2 contains 
analysis of gas collected immediately Methane concentrations as shown in 

after the continuous miner was shut down table 1 average 0.0025 pct. Because the 

for lunch. Analysis of gas samples col- methane sensors have a sensitivity of 

lected from the face 10 days after the 0.01 pct, the average methane percentage 

drilling of several exploratory drill found in table 1 would be recorded as 

holes is shown in table 3. zero from the methane sensor. 

TABLE 1. - Gas analysis from face area collected several days after the last 

production shift, pct 

[Saturday, March 28, 1981 (No salt production)] 

TABLE 2. - Gas analysis from face area collected immediately after a production 

shift, pct 

Sample 

l........................... 

2........................... 

3........................... 

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

5........................... 

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

7........................... 

8........................... 

9........................... 

lo........................... 

ll........................... 

[Monday, March 30, 1981 (Salt production)] 

Sample 

............................... 

2.............................. 

ND Not detected. other hydrocarbons. 

OZ+Nz 

99.03 

99.03 

99.03 

99.02 

99.02 

99.03 

99.03 

99.01 

99.02 

99.03 

99.03 

ND Not detected. 'other hydrocarbons. 

*samples were collected directly from a thin, 6-in stream of gas and brine 

hissing from the face. 

Ar 

0.93 

.93 

.93 

.93 

.93 

.93 

.93 

.93 

.93 

.93 

.93 
TABLE 3. - Gas analysis from face area collected after the drilling of several 

exploratory drill holes, pct 

[Friday, March 15, 1981 (Several days after drilling exploratory holes)] 

Gas samples taken immediately after 

production ceased (table 2) have an average methane concentration of 0.0328 pct 

(samples 1-9). At the same time, the 

methane sensor (inside the exhaust tubing) was recording methane concentrations 

of 0.03 to 0.04 pct. Samples 10 and 11 

were collected from a thin stream of gas 

and brine hissing 6 in (15 cm) out from 

the face. This stream contained approximately 3 pct methane, ethane, propane, 

and butane, and 0 pct CO. 

Sample 

la............................. 

2.............................. 

3.............................. 

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

5.............................. 

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

7.............................. 

8.............................. 

9.............................. 

lo.............................. 

................................ 

12~~. ........................... 132... .......................... 14~ ............................. 

The third set of gas samples (table 3) 

contains an average methane concentration of 0.0151pct. Samples 1 to 11 

were collected several days after drillND Not detected. ' Other hydrocarbons. 

2~ollected near a 150-ft (45-m) exploratory hole drilled May 5, 1981. 

0, + N, 

99.01 

99.01 

99.02 

99.01 

99.01 

99.01 

99.00 

99.00 

These analyses show the reliability of 

the data generated by the electronic 

methane sensing system. Baseline methane 

sensor readings of zero probably contain 

some trace amounts of methane. If an 

average baseline methane concentration 

of 0.0025 pct is assumed (table l), 

approximately 0.3 f t /min (0.0085 m3 /min) 

of methane will be emitted from the 

freshly cut face. Because emissions of 

0.3 ft3/min (0.0085 m3/min) are insignificant, this report will avoid further consideration of baseline methane 

emissions. 

Velocitv Determination 

ing the exploratory holes at the face. Velocity inside the 30-in rigid exhaust 

Samples 12, 13, and 14 were collected duct with two fans operating ranged from 

near the 150-ft (45-m) exploratory 2,900 to 3,300 ft/min (15 to 17 m/sec). 

hole. (See section on Exploratory Drill- Air density determinations and velocity 

ing at Face.) 

Ar 

0.93 

-93 

.93 

.93 

.93 

.93 

-93 

.93 

99.01 .0002 .0080 < .0002 

99.03 I 1 1 , / .0028 1 .0004 

CO 

<0.0002 

< .0002 

ND 

< .0002 

ND 

<.0002 

ND 

ND 

C02 

0.05 

.06 

.05 

.05 

.05 

.05 

.05 

.06 

.0004 

.0008 

.0005 

.0003 

CH4 

0.0043 

.0040 

.0035 

.0046 

.0046 

.0054 

.0083 

.0140 

.0078 

.0500 

.0600 

.0333 

CHI 

<0.0002 

.0004 

<.0002 

.0006 

< .0002 

<.0002 

< .0002 

.0006 

ND 

ND 

ND 

ND 

99.01 

98.96 

98.96 

98.97 

.93 

-93 

.93 

.93 

.05 

.06 

.06 

-05 
pressure measurements from pitot tube 33 , 

surveys were used to determine velocity. 

The sonic anemometer was not used to 5 ~ 

determine the velocity of the air in the 

exhaust duct because of a nonlinear 

increase in voltage output with increas- a [r ing velocity; it did provide a basis for g 1 32 

establishing times of product ion and no 

production. w z 

LT Pitot tube surveys were conducted by a 

m inserting the tube through a small hole 

in the exhaust duct, permitting velocity 

pressure to be measured with a manometer 3 1 

gage. Six 10-point transverses along a 110 

horizontal and vertical axis were conducted for each survey. Vel~city pressure in inches of water is changed into 0 100 G velocity (feet per minute) by multiplying 

the square root of each velocity pressure 

by 4,000 (3). Average velocities from 90 

six pitot tube surveys were used to cal- a IJJ 

culate an average velocity of 3,100 5 

100 ft/min (16 5 1 mlsec). + 80 

Air density was considered in cal- I I 

culating true velocity. Temperature, 

barometric pressure, and relative humidity are variables that should be measured arch+- ~pri I May -4 

to determine density. Temperature and TIME, days 

barometric pressure were measured on a 

daily basis at variable times and are FIGURE 8. - Temperature and barometric presshown in figure 8. Relative humidity sure measurements recorded in the 

was measured, but the reliability of decline during the investigation. 

these data are questionable, so this 

information was not included. Air dens- (0.075 lb/ft3) divided by the measured 

ity ranged from 0.071 to 0.078 lb/ft3. air density (table 4). Air density meaTrue average velocity was calculated by surements and true average velocity calmultiplying the average velocity of 3,100 culations for each of the 18 production 

100 ft/min (16 ' 1 m/sec) by the square days are given in figures A-1 to A-18. 

root of the standard air density 

TABLE 4. - Air velocity and quantity ranges within exhaust tubing for varying 

air densities 

Air density, 

lb/f t3 

0.071 

.076 

.077 

.078 

True velocity 

Minimum, 

f t/min (mlsec) 

3,100 (16) 

3,000 (15) 

3,000 (15) 

2,900 (15) 

- Air quantity 

Maxiumum, 

f t/min (mlsec) 

3,300 (17) 

3,200 (16) 

3,200 (16) 

3,100 (16) 

Minimum, 

f t3/min (m3 Isec) 

15,200 (7) 

14,700 (7) 

14,700 (7) 

14,200 (7) 

Maximum, 

f t3/min (m3/sec) 

16,200 (8) 

15,700 (7) 

15,700 (7) 

15,200 (7) 
The sonic anemometer continuously 

recorded approximate centerline velocity 

within the exhaust duct. The sonic anemometer was not used to determine velocity because of nonlinear changes in output signal with changing velocity. Other 

possible factors impairing accurate 

velocity measurements were production of 

salt dust at the face, voltage surges 

from the operation of other electrical 

face equipment, and short calibration 

life. However, the sonic anemometer was 

useful in approximating the duration of 

salt product ion. Abnormal responses from 

the instrument are associated with salt 

production (figs. A-1 to A-18). Minutes 

of salt production time per day are 

approximated by adding intervals of 

abnormal responses from the sonic 

anemometer. 

Methane Emission Rates 

Methane was emitted from the advancing 

face at a rate ranging from 15 to 56 ft3/ 

ton of salt mined per day (0.5 to 

1.8 m3/t). Methane emission rates were 

determined by measuring the total quantity of methane emitted per day, determining a production rate from tonnage and 

production time data, and calculating a 

daily emissions rate per ton of salt 

mined per day. Each range of daily emission rates was then added and divided by 

the total number of production days to 

determine the average emissions rate for 

this preliminary study. 

Daily methane emissions, which ranged 

from approximately 1,000 to 8,000 f t3/day 

128.3 to 226.6 m3/day (fig. 9) 1, were 

March-++ Apri I May 

TIME, days 

FIGURE 9. - Daily range of methane emissions from the advancing decline. 
calculated as follows. The percentage of 

methane in the exhaust duct was measured 

every 15 min during a production shift 

with the sensor inside the tubing. 

The air velocity in the duct was considered constant for each production day 

(table 4), but methane concentration changed continuously (figs. A-1 to 

A-18). Instead of assuming a constant 

methane concent ration between measurements, a numerical integration technique 

known as Simpson's rule was used (6). 

Simpson's rule interpolates a quadraric 

polynomial between each 15-min measurement of the methane concentration. Each 

of these curves were then integrated and 

their resuiting areas summed to estimate 

the total amount of methane exhausted 

through the 30-in tubing during salt 

production. 

Methane emission rates are compared 

with salt production rates. Two independent measurements of production rate 

were used. One measured the total minutes of salt production time (fig. lo), 

and the other the total tons of salt 

hauled by the load-haul-dump (LHD) machines (fig. ll). Both sets of data have 

error involved in estimating the tons of 

salt mined at the face. Measuring the 

minutes of production time does not diff erentiate continuous miner down-t ime 

while LHD's are operating. The tonnage 

data supplied by the operator was based 

on salt hauled by the LHD's, not by the 

actual tons mined by the continuous 

miner. 

A more accurate estimation of the mining rate was obtained by comparing daily 

tonnage data with daily production time 

as determined from sensor system (figs. 

A-1 to A-18). Figure 12 is a comparison 

of the total tons of salt hauled per day 

by LHD's with the total minutes of salt 

production per day (estimated from sensor 

charts, figs. A-1 to A-18). These data 

provide a more realis tic approximation 

of the mining rate of the decline 

advancing face. These charts A-1 to 

A-18 (see appendix) showed discrepancies 

between haulage data and production time 

1 I I 1 1 1 1 

12 16 20 24 28 

March- April 

TI ME, days 

FIGURE 10. - Methane emission rates from advancing 

decline using production time for rate estimates, 

Minutes of production per day were measured from 

charts in the appendix (figs, A-1 to A-18). 

~arch4-~pnl d~ay 

TIME, days 

FIGURE 11, - Methane emi ssion rates from advancing 

decline using tons of salt hauledfor 

rate estimates, Tonnage data was supplied by the operator, 
0 100 200 300 400 500 600 700 

PRODUCTION, min/day 

I I I I I 

- 4-28h04G - 

- KEY - 

A 

- Yz23.3-0.34X - 

- r2=0.92 - 

- 

l Data points - 

- 

0 Data points known to - 

- be in error - 

- . Corrected data points - 

- - 

- 

FIGURE 12. - A comparison of tonnage (salt hauled) with production time (measured from charts) 

enables calculation of decline production rate. 

- 

05-30 I - 4-60 @47-24 1 0 

- 3-31 

- r 04-21 

- 

- 4-22. 7! 

04-29 - 

measurements. These discrepancies are 

shown as open circles in figure 12. Each 

of these data points represents inaccurate tonnage data, because salt was 

evidently mined but not hauled during one 

of the two production shifts. If these 

six misrepresented data points are 

ignored and linear regression is performed on the remainder, the equation for 

the line that best fits the data can be 

determined. Calculation of corrected 

tonnage data is done by substituting 

the minutes of production for each of 

the six misrepresented data points into 

- 

- 

- 

- 

- 

- 

0 

- 

the equation for the line representing 

production rate in the decline (fig. 12). 

An approximate methane emissions rate, 

based on the cubic feet of methane 

emitted per ton of salt, was then 

calculated by dividing the total 

methane by the tons of salt mined 

at the face for each day. These data 

are shown in figure 13. Dashed bars 

in figure 13 represent inaccurate tonnage 

data determined from comparison of daily 

tonnage data with daily production time 

(fig. 12). The daily range of methane 

- 0 - 

0 - - 

I I I I I 
;; I .o 

.8 

w .6 Z 

a .4 

f .2 

.O 

I 10 pm 12 mid 2 4 6 am 8 10 12 noon 2 

+ 5/6/81 

t; 1.0 

.8 

w .6 z 

a .4 

I 

I- .2 

g .o 

I 

4 8 10 12 mid 2 4 6 am 8 10 

5 / 7/81 

FIGURE 14. - Strip-chart recording of methane emissions during drilling of an exploratory drill hole. 
TABLE 5. - Gas analysis taken approximately 1-ft (0.3 m) inside 

the collar of a 300-ft (91-m) exploratory drill hole, pct 

(Friday, May 15, 1981) 

ND Not detected. lother hydrocarbons. 

2~oncent rat ions represent minimum values. 

SUMMARY AND CONCLUSIONS 

Sample 

l........ 

2 ........ 

3 ........ 

4 ........ 

In driving a decline, the advancing 2. Methane emissions decrease with 

face emits methane at a rate ranging from time after a production shift. 

15 to 56 ft3/ton (0.5 to 1.8 m3/t). 

Daily methane emissions from the decline 3. Methane concentrations in the rewere approximately 1,000 to 8,000 ft3/day turn air were less than 0.01 pct within 

(28.3 to 226.6 m3/day). The average several hours after production. 

production time was approximately 

6.3 hr/day, while the average tonnage was 4. Variations in methane emission 

105 tons/day. rates occur during face advancement. 

CO 

ND 

ND 

ND 

ND 

The investigation showed that: This study found that geologic and geochemical characteris tics of domal salt 

1. Measurable methane emissions do influence methane emission rates during 

occur within the low-grade salt during production from advancing faces. 

production, 

O2 + N2 

35.18 

34.41 

40.45 

76.19 

REFERENCES 

CH4 

61.52 

62.30 

56.45 

21.10 

1. Howard, J. C. Computer Simulation 

Models of Salt Domes. Bull. AAPG, v. 55, 

No. 3, March 1971, pp. 495-513. 

Ar 

0.33 

.32 

.38 

.72 

2. Hyman, D. M. Methodology for Determining Occluded Gas Contents in 

Domal Kock Salt. BuMines RI 8700, 1982, 

15 PP* 

CHI 

0.83 

.85 

.82 

.21 

C02 

2-12 

2.10 

1-90 

1-78 

3. Kingery, D. S. Introduction to 

Mine Ventilating Principles and Practices. BuMines B 589, 1960, pp. 9-15. 

4. Kupfer, D. H, Problems Associated 

With Anomalous Zones in Louisiana Salt 

Stocks, USA. Proc. 5th Symp. on Salt, 

pub. by Northern Ohio Geological Society, 

Cleveland, Ohio, v. 1, 1980, pp, 119-134. 

soZ2 

0,0058 

,0071 

.0058 

.0026 

5. Paine, W, R.,M. W.Mitchel1, R. R. 

Copeland, Jr., and L. de A. Gimbrede. 

Frio and Anahuac Sediment Inclusions, 

Belle Isle Salt Dome, St, Mary's Parish, 

Louisiana. Bull, AAPG, v. 49, 1965, 

pp. 616-620. 

CH~SH~ 

0.0017 

,0025 

,0018 

.0011 

6. Shampine, L. F., and R. C. Allen. 

Numerical Computing: An Introduction. 

W. B. Sanders Co,, 1973. 

7. Thoms, R. L., and J. D. Martinez. 

Blowouts in Domal Salt. Proc, 5th 

Symp. on Salt, pub. by Northern 

Ohio Geological Society, v. 1, 1980, 

pp. 405-411. 
10 12 mid 

4/ 1 /81 

*Voltage output 

FIGURE A-2. - Day 2: Air density = 0.077 pcf and average air velocity = 3,100 + 100 ft/min. 
l8/£/b 18/Z/ t7 

Z P!"J ZI 0 1 8 wd 9 t7 Z UOOUZ~ woo1 I 

*U!LU/J~ 001 T OOO'& = Al!lola~ J!D ~~DJ~AD puo j3d 8~0.0 = A,!suap J!V :& Aoa - '&-v 3dn314 

18/ 2 /b l8/l/b 

P!U 2 1 0 1 8 2 uoou 2 1 ~UD 01 I 
I 8 am 10 12noon 2 4 6 pm 8 10 12 mid 

4 / 7/81 4/ 8/81 

I +Voltage output 

No ~roduction t ~roductiont f-- ~roduclion + shift change f ikEtd- Production production 

~unch 

break 

Production 

FIGURE A-6. - Day 6: Air density = 0.077 pcf and average air velocity = 3,100 + 100 ft/min. 
10 am 12 noon 

4 /9 /81 

10 12 mid 2 

4/10/81 

I Voltage output 

- productioni No Prod.ctioni +Production+ change shift t Production j~uncht break Production* No productionLunch 

break 

FIGURE A-8. - Day 8: Air density = 0.076 pcf and average air velocity = 3,100 + 100 ft/min. 
+Voltage output 

- NO productionf-- Production -1~hift 1 production NO f production 

-- 

+O tP 

FIGURE A-9. - Cay 9: Air density = 0.077 pcf and average air velocity = 3,100 + 100 ft/min. 

I 

8 am 10 12 noon 2 4 6 Pm 8 10 

4/15/81 

I +Voltage output 

, NO + Production -i No production No production w 

production 

Product ion 

FIGURE A-10. - Day 10: Air density not available, average air velocity = 3,100 2 100 ft/min. 
t I 0 

.8 

.6 z 

< .4 

: .2 

.o 

I 8 am 10 12 noon 2 4 6 Pm 

4/16/81 

'Il-Llrl~Lll~lllrlll~'~~'~~~'tl~~'LaL'A 

+Voltage output 

FIGURE A-1 1. - Day 11: Air density = 0.071 pcf and average air velocity =: 3,200 + 100 ft/rnin. 

+Voltage output t No production t Production f NO production- 

*oQ 

tiQ'O 

+O 

FIGURE A-12. - Day 12: Air density - 0.076 pcf and average air velocity - 3,1002 100 ft/min. 
I 12 noon 

* 

*Voltage output 

Production Production Production Production 

FIGURE A-13. - Day 13: Air density = 0.076 pcf and average air velocity = 3,100 2 100 ftlrnin. 

*Voltage output 

r NO {ROdUction~Lunch production t Shift 1- Production ---I Production t No production - production break change 

Lunch 

break 

FIGURE A-14. - Day 14: Air density = 0.076 pcf and average air velocity = 3,100 + 100 ft/min. 
I loam 12noon 2 4 8 10 12 mid 2 

4/27/81 4/28/81 

-No produof~on 1 -/ j~roducfiont cE:Ae +- ~~~d~~fi~~--f t + No production , 

f f t t 

FIGURE A-16. - Day 16: Air density not available, average air velocity = 3,100 + 100 ft/min. 
I *Voltage output 

Production No production Production INOt tt + No production - f I production 

Production 

FIGURE A-18. - Day 18: Air density = 0.076 pcf and average air velocity = 3,100 "00 ft/min. 

*U.S GOVERNMENT PRINTING OFFICE. 1982 - 605 - 015/93 INT.-BU.OF MINES,PGH..PA 26391