I I I 

Bureau of Mines Report of Investigations/l974 

Tracer Gas as an Aid 

in Mine Ventilation Analysis 

UNITED STATES DEPARTMENT OF THE INTERIOR 
TRACER GAS AS AN AID IN MINE VENTILATION ANALYSIS 

by 

E. D. Thirnonsl and F. N. Kissell2 

ABSTRACT 

The Bureau of Mines has successfully used sulfur hexafluoride (SF,) as a 

tracer gas to measure mine air flows under conditions where conventional 

methods have failed . SF, was employed experimentally to measure accurately 

recirculation of return into intake air caused by leakage through an old 

stoped area, to check for potential leakage from an adjacent mine, to trace 

10,000 ch of "lost1' air from an intake airway, and to measure transit air 

time through uranium mines. It proved useful as a means of accurately measuring airflow volumes in airways of large cross section and very low flow velocity, and in determining the recirculation resulting from underground cooling 

plants. 

INTRODUCTION 

Mine ventilation systems are generally very complex. Many aspects of a 

mine ventilation network can be studied by conventional anemometer and smoke 

cloud techniques. However, problems such as recirculation of return into 

intake air, leakage from adjacent mines, "lostI1 intake air, uncertain flow 

quantities in airways of large cross section and low velocity, and unknown 

transit flow times through stoped areas call for new ways of analyzing airflow 

underground. Use of SF, as a tracer gas can be an effective means of analyzing these ventilation problems. The Bureau of Mines is concerned with finding 

solutions to these problems in conjunction with its ventilation programs. 

Various studies have been conducted by the Bureau in several mines in order 

to show the value of the SF, tracer gas. 

Organic and inorganic chemicals, and radioactive substances have been 

used for trace purposes, but most of these materials have inherent disadvantages. Chemical tracers are less easily detected at low concentrations than 

radioactive substances , and are of ten highly adsorbed on many surfaces. Radioactive substances , on the other hand, can be detected in low concentrations , but are difficult to handle and are likely to be unacceptable to men working 

underground. An effective tracer gas must be detectable at low concentrations, 

l~esearch physicist. 

2~hysical research scientist. 
well was plugged. The success of the 

plugging technique in preventing reservoir gas from entering the mine atmos- L phere through the well holes was veriI fied by monitoring the mine air twice 

I . daily for indications of the trace gas. 

FIGURE 1. - SF6 lecture bottle with 0.006- 

inch hole drilled in cap. %nderlined number in parentheses refer 

to items in the list of references at 

the end of this report. 
FIGURE 2. - SF6 lecture bottle and syringe sample bottles. 

41f the concentration of a given sample appears -low as compared with those of 

the other samples, we check this syringe bottle in the laboratory by filling the bottle with a known amount of SFG and measuring its concentration 

again after several days. 
102 (60-80 mesh)5 that has been treated at 100" C for two hours. The operating temperature is 50" C. The carrier gas is argon with 5 percent methane, 

flowing at 10 cm3 per 17 seconds. A 0.1-milliliter gas sample is injected 

into the chromatograph. The resulting analysis is read by a digital voltmeter 

and printed out at a rate of 20 readings per second. SF, peak heights are 

used for calibration and analysis. A detailed discussion of the chromatograph 

calibration procedure is given elsewhere (lo). 

PRELIMINARY TRACER GAS EXPERIMENTS 

To determine if SF, could be traced quantitatively underground, preliminary experiments were conducted in the Bureau of Mines Safety Research Coal 

Mine, located at Bruceton, Pa. This mine (fig. 3) has a single intake and 

exhaust and is an ideal facility for testing a trace gas. In these experiments a known quantity of SF, was released into the intake air at R, and 

after a few minutes the return air was sampled at S every 2 minutes for a 

period of 90 minutes. The samples were run on the chromatograph to determine 

FIGURE 3. - Bureau of Mines safety research coal mine. 

---------------- - --- - - - - - -- -- 

B butt 

A butt '== D 

R D %I LEGEND 

2 butt s 

u 

Scale, feet 

1 

a 

'g5Reference to specific trade names is made for identification only and does 

not imply endorsement by the Bureau of Mines, 

----, Intake air 

Return air 

Door 

Regulator t. c. Curtain 

Temporary stopping -= Permanent stopping .----- Brattice 

X Release location 

A Sampling location 
the SF, concentrations. The quantity of SF, passing in the return was es timated by substituting the resulting data into the following equation: 

QSF, = QAIR cdt. 

Here, Qs, is the SF, volume, Qr is the volumetric airflow rate at the sampling and c is the SF, concentration at time t. Integration of this 

equation is simply done by multiplying C,, , , the average SF6 concentration in 

those sample bottles that contain SF,, by the total time T during which measurable amounts of SF6 were found in the return air. This total time T is the 

sampling interval (2 mirPicnc ,,," in this case) multiplied by the number of samples 

with a measurable SFB concentration. Thus, the above equation reduces to 

QS F6 = Ql\ (R C.V T. 

Results of a typical experiment were as follows: 10.5 liters of SF, were 

released in the intake. Of the 45 air samples taken in the return at 2-minute 

intervals, 31 contained measurable quantities of SF, with an average concentration of 377 parts per billion (pbb). The SF, concentration of each sample is 

assumed to represent the SF, concentration at S over a 2-minute interval (from 

1 minute before the sample is taken until 1 minute after it is taken). Therefore the 31 samples containing SF, indicate the presence of SF, in the return 

for a period of 62 minutes at an average concentration of 377 ppb. The SF, 

concentration in the return is plotted as a function of the time from the 

release of SF, in the intake in figure 4. The return volume airflow was 

0 10 20 30 . 40 50 60 70 80 90 

TIME FROM RELEASE OF SF6, min 

FIGURE 4. - SF6 concentration in the return as a function of time. 
16,280 cfm. Using the continuity equation given above, the calculated quantity of SF^ in the return is as follows: SF, (liters) = (16,280 ft3 air/min) 

(377 x ft3 s~,/ft~air) (62 min) (28.3 liter/ft3) = 10.7 liters. This is 

in good experimental agreement with the original value of 10.5 liters released 

in the intake. Results with this degree of accuracy were obtainable only if 

the SFB was thoroughly mixed with the mine air. 

EFFECT OF DEEP MINING CONDITIONS ON TRACING WITH SF, 

A major concern in the development of the tracer gas technique was that 

it might not be effective in deep mines, where some of the SF, might be washed 

out by cooling plants or lost in the long multilevel air paths or in stopes. 

To determine the effect of such conditions, an experiment was conducted in a 

western copper mine in which most of the ventilation air passed through cooling plants, heavily s toped areas, and over long distances (up to 4 miles) 

before exiting the mine. This mine has been worked since the 19th century 

and has an extremely complicated and extensive ventilation network. A simplified schematic of the mine is shown in figure 5. The experiment began with 

the release of 68.9 liters of SF, into the intake air from 9:30 a.m. to 

Exhaust 

Exhaust 

! 

A 

A 

Sampling point Sampling point 

No. I No. 2 - d 

A - f 

Release 

location 

plant 

A 

11 

f - 

A 

+ 

Cooling - - A 

plant A Sampling point 

No. 3 

FIGURE 5. - Schematic of copper mine. 
9:32 a.m. Air samples were taken at 5-minute intervals from 9:30 a.m. to 

12:OO noon at each of three sampling points (fig. 5). Air passing these three 

locations encompassed the entire exhaust air supply from the mine. The test 

results are presented in table 1. The total SF, from the three exhaust sampling locations is 70.4 liters. The volume of SF, released was 68.9 liters, 

indicating an error of about 2 percent. This indicates the SF, gas is not 

washed out to any measureable extent by passing through cooling plants, and 

is not lost due to the long air transit time in the mine or by traveling 

through stoped areas. 

TABLE 1. - Results at the three sampling locations 

irL a ~.rnci-nvn w,o ,,, ,, cGpper mifie 

- 

3 1106,00019:40 a.m. lll:25 a.m.[ 22 I 110 1 104.3 1 34.5 

 SF, released from -9:30 to. 9:32 a .m. 

RECIRCULATION MEASUREMENTS USING SF, 

Sampling 

location 

1 

In multilevel mines, recirculation of return air into intake airways 

can be a serious problem. Generally, it is due to leakage through stoped 

areas that are inadequately sealed. In the event of a mine fire, the recirculated air can contaminate the intake escape route with toxic gases. To 

prevent recirculation, one must first determine the extent to whicp it occurs 

and find where the leakage is taking place. Tracer gas can be applied for 

this purpose. 

2 1 65,00019:35 a.m.lll:50 a.m.1 28 1 140 1 69.5 1 17.8 

Time of 

last 

SF, at 

location 

11:20 a.m. 

Two tracer gas experiments were conducted in a western metal mine where 

recirculation was known to occur (fig. 6). To determine the percentage of 

the return air leaking through the stopes into the intake, a measured volume 

of SF, was released into the return, and intake air samples were periodically 

taken. The percentage of the return air recirculated into the intake was 

calculated from the ratio of SF, in the intake to the total SF,. 

Airflow 

rate, 

cfm 

66,000 

In the first experiment, 32.4 liters of SF, were released from 10:45 to 

11:OO a.m. at R1 in the return, where the air flow was 86,000 ch. Air 

samples were cxlected at L-minute intervals from 10:45 to 11 :37 a.m. at 2, 

where the flow was 87,000 ch. Sample analysis showed that SF, first appeared 

at at 10:59 a .m. and continued in measurable concentrations until 11: 19 

a.m. (fig. 7). The calculated volume of SF, to have passed was 2.1 liters, 

indicating recirculation in this area to be slightly greater than 6 percent. 

Arrival 

time of 

SF,' 

9:55 a.m. 

In the second recirculation experiment, 8.6 liters of SF, were released 

from 1:10 to 1:23 p.m. at - R2 in the return. The air flow at R2 was 7,000 ch -CI 

Number of 

samples 

containing SF, 

16 

- Time SF, 

was present, min 

(number of 

samples x 

5 min) 

80 

Average 

SF, 3 

concentration 

ppb 

121.8 

TO ti1 SF, 

to pass 

this location, 

liters 

18.1 
LEGEND 

Intake a 

6 Return air 

--- Possible leakage 

c? Fan 

X Release location 

A Sampling location 

0- 

25,000 cfm -4 

mine 

FIGURE 6. - Western metal mine where recirculation 

experiments were conducted. 

TIME FROM RELEASE OF SFg, min 

but increased considerably 

further up the return. Air 

samples were taken in 5- 

minute intervals from 1:10 

to 2:45 p.m. at S2 in the 

intake, where thyairf low 

was 58,000 cfm. The first 

recirculated SF, appeared in 

the sample taken at 1:40 

p .m. , and varying amounts of 

SF, were found until 2 :35 

p.m. Figure 8 shows the SF, 

concentration at as a 

function of time from 

release. The calculated 

volume of recirculated SF, 

was 5.3 liters, indicating 

61 percent recirculation. 

Without further experiments, 

it is impossible to determine if 61 percent of the 

7,000 cfm at the release 

location was recirculated or 

if 61 percent of some larger 

volume of return air was 

recirculated. This depends 

upon where the leakage 

occurred. If some leakage 

occurred above the level 

where the 25,000 ch enters 

the return shaft, then it is 

61 percent of a larger air 

volume. Other tracer gas 

experiments, with the 

release or sampling points 

located further up the 

shafts, would be required to 

determine where the leakage 

occurred. 

FIGURE 7. - SF6 concentration in the intake during 

first recirculation test. 
0 10 20 30 40 50 60 70 80 90 100 

TI ME FROM RELEASE OF SF6, min 

FIGURE 8. - SF6 concentrat ion in the intake during second recirculation test. 

FACE VENTILATION ANALYSIS IN A ROOM-AND-PILLAR MINE 

Tracer gas was employed to evaluate face ventilation in a Pennsylvania 

limestone mine worked by the room-and-pillar method. At the time of the experiment, the last room on the working face was 16 room (fig. 9)" Dust and 

diesel fume concentrations around 16 room were high. It was assumed that 

intake air was not reaching 16 room in sufficient quantities. To check this 

assumption, a known amount of SF, was released into the intake air and the 

amount of SF, reaching 16 room was measured. 

Thirty liters of SF, werereleased in the intake air at 5 room (fig. 9) at 

9:54 a.m.; gas sampling began at 9:54 at both the junction of 16 room and 10 

butt, and in 9 butt about 50 feet down air from the auxiliary fan mounted 

between 13 and 14 rooms. The auxiliary fan exhausted the air from the working 

face. Samples were taken in both locations every minute until 10:30 a.m. The 

samples taken in 16 room showed slight traces of SF, (about 1 ppb) from 10:04 

until 10:18 a.m. In 9 butt the samples showed more than 100 ppb SF, after 

only 2 minutes and continued to show these high concentrations throughout the 

remaining 34 minutes of sampling. Since the SF, in the return air in 9 butt 

generally exceeded 100 ppb and the SF, in 16 room was 1 ppb or less, it would 

appear that only 1 percent or less of the intake air ever reaches 16 room. 

The auxiliary fan is evidently exhausting the air before it reaches 16 room, 

resulting in high concentrations of dust and fumes. 
LEGEND 

/-/6 Entry numbers 

Release location 

A Sampling location $ Curtain stopping 

s Fan - Main intake air 

--+ Weak intake air 

Return air 

butt 

0 - 100 200 

Scale, feet 

FIGURE 9. - Area of limestone mine where face ventilation experiment was conducted. 

USE OF TRACER GAS TO MEASURE AIRFLOWS 

One important use of tracer gas is to measure volume flow rates i n a i r - 

ways where the cross section in too large and/or the velocity is too low for 

standard measurements. An experiment of this type was conducted in a Pennsylvania limestone mine with a vertical natural draft intake hole about 70 feet 

deep and about 20 feet in diameter. The hole carries intake air from the 

surface down to an airway of about 800 fta cross-section. Since the cross 

section was too large and the velocity too low to use an anemometer traverse, 

the volume flow rate down the intake was measured with the tracer gas 

technique. 

Around the surface perimeter of the hole, 12.2 liters of SF, were released 

from a lecture bottle. The gas was released in a jet spray directed down 

into the hole to insure that all the gas entered the mine. Starting simultaneously with the SF, release, samples were taken every minute for 35 minutes 

at a station in the intake airway located 70 feet from the bottom of the 

vertical hole. Of the 36 samples taken, 27 contained SF, at an average concentration of 470 ppb. Assuming that all the SF, released entered the intake 

hole, the volume airflow rate into the mine from the natural draft intake can 

be calculated from the continuity equation: Q, ,= = QA Cav T. In this case, 
Q, , , is the airflow rate, QsF is the volume of SF, released, C,, is the average SF, concentration in the ,27 samples containing SF,, and T is the 27- 

minute time interval that these samples represent. Therefore 12.2 liters = 

(470 x loo9 ft?SF, /ft3 air) (28.3 liters/ft3) (27 min) (Q , ) From this we 

can calculate QA ,,, the airflow rate, and we find that QA , , = 34,000 cfm. 

AIR LEAKAGE EXPERIMENTS 

Multilevel mines with invo lved ventilation patterns , large stoped areas, 

and numerous bulkheads are often subject to serious air leakages that are difficult to track down. The tracer gas can be useful here, as was shown in 

three separate experiments conducted in a western metal mine where several 

major air leakages were known to exist. 

Experiment -~ 1. --Figure 10 is a general schematic of the airflow pattern 

in the mine. After passing through the stopes the exhaust airflow was about 

55,000 cfm. At the top of shaft No. 1, just beyond the inclined shaft 

junction, the flow was 117,000 cfm. It was about 120,000 ch at the exhaust 

shaft, showing an increase in the return air volume of 65,000 cfm, of which 

12,000 cfrn could be credited to leakage through the bulkhead at the bottom of 

the inclined shaft. The problem was to account for the other 53,000 cfm. One 

good possibility was that air was leaking from the old workings of an adjacent 

mine into No. 1 shaft, which was inaccessable to an anemometer survey. 

Almost 70 liters of SF, were released into the intake (Rl) of the adjacent mine from 11:02 to 11: 15 a .m. Air samples were taken atthe exhaust 

fan (2) of the working mine from 11:30 a.m. to 3:00 p.m. If there was 

leakage from the old mine, the SF, would have shown itself in measurable 

concentrations by then, as can be seen from the following calculation. The 

70 liters of SF, was equivalent to about 2.5 ft3. The airflow in the adjacent mine was around 20,000 cfm. Assuming that the SF, spreads itself out 

in the adjacent mine over a period of 1 hour, then its concentration could 

be calculated as follows: 2.5 ft3 = 2.1 x lo", or 2.1 ppm. 20,000 ft3/min x 60 min 

If only 1,000 ch leaks into the working mine and is diluted in 120,000 cfrn 

then the SF, concentration in the working mine could be calculated as follows: - 

2.1 x loo6 ft3 SF OoO ft3 air = 1.75 x loe8, or 17. 5 ppb, which would ETS' X~O,OOO ft3 air 

be easily detected. Since no SF, showed in any of the samples taken, it can 

be concluded that the unaccounted for air does not come from the adjacent mine. 

Experiment 2. --A second possibility was leakage from the inclined shaft 

through old stopes and down into No. 1 shaft (fig. 10). To explore this 

possibility 8.6 liters of SF, were released at the top of the inclined shaft 

at at 8:55 a.m. and sampling was started at the top of No. 1 shaft at __. S2 

and just behind a leaky bulkhead in the inclined shaft on the return air side 

at ~3. Samples were taken at 5-minute intervals until 10:30 a .m. Analysis 

shozd that 4.4 liters of SF, showed at S2 and 6.3 liters of SF, showed at - S3. 

This is a total of 10.7 liters of SF,, wGreas only 8.6 liters had been 

released. This discrepancy probably resulted from the fact that SF, appreared 
LEGEND 

- Intake 

+- Exhaust 

---* Possible leakage 

Fan 

Release location 

A Sampling location 

FIGURE 10. - Schematic of mine where leakage tests were conducted. 

in only a small number of samples, thus reducing the accuracy of the numerical 

integra t ion. 

Since some SF, did show at the top of No. 1 shaft, we know that there is 

some leakage from the inclined shaft through the old stopes and into the 

return air somewhere below the top of No. 1 shaft. However, other considerations would indicate that this leakage is small. An anemometer traverse at 

the top of the inclined shaft at R2 indicated a flow of 2,000 cfm down the 

shaft at this point. On the otheaand, 12,000 cfm was leaking through the 

bulkhead at S3, indicating, rather surprisingly, that the net leakage in the 

shaft was inTnd not out. 

The SF, travel time between release at R2 and the first appearance at 

- S3 was 50 minutes. The distance traveled down the inclined shaft was 1,700 

feet, indicating a velocity of 34 ft/min. If the shaft cross section was 60 
f t2 , then the average airflow was 2,040 cfm. This indicates that most of the 

leakage into the inclined shaft took place near the bottom and very close 

to - S3. 

Experiment 3.1-This experiment took place in a different portion of the 

mine. The intake air volume on C level (fig. 11) was 51,500 ch. At the 

junction of C level and No. 8 shaft this air volume splits three ways : up 

and down No. 8 shaft and through the C level doors on the other side of No. 8 

shaft. These three air volumes were measured, they totaled to 38,300 cfm, 

leaving a loss of 13,200 c£m of air somewhere along C level. Leakage through 

cracks from the C to the B level was suspected. 

A known amount of SF,, 6.6 liters, was released at R on the C level at 

11 :57 a .m. , and sampling began next to No. 8 shaft on th; B level (Sl) and 

about 1,500 feet further along B level (S2). The results revealed Go 

significant facts. First, SF, arrived aTs2 at 12: 17 p.m. , but did not reach 

S1 until 12:26 p.m. , indicating that some z6 did leak from the C to the B 

level. Second, the total volume of SF, passing 52 was 0.5 liter more than the 

volume passing z. This 0.5 liter is obviously xe volume of SF, that leaked 

through. The lost air volume was 13,200 cfm; if all of this were going to 

the B level, the SF, quantity difference would have been 13,200 c£m/51,500 

cfrn x 6.6 liters = 1.7 liters. Since only 0.5 liter extra showed up on the 

No. 8 shaft 

FIGURE 11. - Leakage test on C level. 

- - 

A level 7r 

B level A S2 - SI A w 

t 

I 

I Posslble 

I 

E + 

I leakage 0 

o 

1 

path 1 0 

I 

I 

I 

- X 

Doors 

C level @R - 51,500 cfm ---+ 2,000 cfm 

LEGEND 

- Intake 

b Return 

---* 0 Leakage 

Sampling 

Release location 

location 

ma 

(U 

" 1 

w- E 

0 

Stoped 

area 
B level, it would seem that less than one-third of the lost air goes to the 

B level. The remaining lost air must leak elsewhere. 

It is interesting to note that although the straight distance between 

the C and B levels is only 300 feet, it took 20 minutes for the SF, to arrive 

at S2. If the leakage was about 4,000 cfm, the cross section through which 

theleakage air passed must be large. 

COOLING PLANT RECIRCULATION EXPERIMENTS 

In deep mines, the air temperature is maintained at tolerable levels by 

underground c~oling plants that may cause large volumes of air to be recirculated in the mining areas. In case of a mine fire, the cooling plants could 

recirculate contaminated air. The amount of recirculation occurring at two 

cooling plants in the western copper mine was determined quantitatively by 

releasing a given volume of SF, into the intake of the cooling plant and 

monitoring this intake for the next two hours. 

If the volume of SF, released is R and the fraction recirculated is n, 

then the volume of SF, returning the first time around is nR. The second 

time around the volume is n2~, and the third time it is n3~, and so on. The 

sum of this series is A - A\ R, where A is the total volume of SF, -( Ian, 

recirculated. In this case, A is the volume of SF, monitored at the cooling 

plant intake during the e~periment.~ It can be seen from table 2 that approximately 50 percent of the air passing through these cooling plants is recirculated. A concentration-time curve for the second cooling plant is given in 

figure 12, where the individual peaks most likely represent recirculation 

along different paths. 

TABLE 2. - Results of cooling plant recirculation tests 7 - 

AIR TRANSIT TIMES IN URANIUM MINES 

Coo ling 

plant 

1 

2 

Radon daughter levels in uranium mines are a function of the mine air 

transit times, since the levels increase with time after mining. Therefore, 

the shorter the air transit time underground, the lower the radon daughter 

levels. Unfortunately , the complexity of the air patterns underground makes 

it difficult to estimate air transit times. The trace gas technique again 

provides a straightforward solution 

6This approach was not used in the experiments discussed previously to measure 

recirculation from return into intake airways because SF, monitoring was 

discontinued before the gas could return a second time. 

SF, released (R) 

liters 

19.1 

31.1 

Total volume 

of SF, recirculated @) 

liters 

22.9 

26.1 

Recirculation 

factor (n) 

0.54 

.46 
TlME FROM SF6 RELEASE, min 

FIGURE 12. - SF6 concentration versus time for cooling plant test. 

Trace gas experiments to determine air transit times were conducted in 

three southwestern uranium mines, each of which had a major intake with three 

exhausts (table 3). A known volume of SF, was released into the intake shaft - on the surface and bottle 

500 1-1 gas samples were taken at 

mine exhaust shaft. 

400 

300 

n (1 

a 

ci, 

LL 

m 200 

100 

each of the three exhausts 

for one hour afterwards. 

- 0 0 Figure 13 shows a concentration curve for the SF, 

exhausting from one of the 

upcast shafts. This curve - is typical in that for all 

nine of the exhaust shafts 

monitored, the peak SF, con- 

- centration appeared in less 

than 30 minutes ; in almost 

every case some residual SF, 

was still in the mine an - 1 hour after release. 

Therefore, in all three 

0-1 1 0 mines tested the bulk of the 

0 10 20 30 40 50 60 SF, had exited within an 

TIME FROM SF6 RELEASE, min hour after release into the 

intake. The fact that not 

FIGURE 13. - SF6 concentration curve from a uranium 
all the tracer gas could be accounted for is probably due to the large number 

of dead headings in the mines. 

TABLE 3. - Results of transit air time tests in uranium mines 

SF6 SF, Mine and exhaust shaft released, exiting, 

liters liters 

- 

Mine 1: 

Exhaust shaft 1-1.. - 6 4 

Exhaust shaft 1-2. . 1 a I i2.2 

not 

accounted 

for, 

liters 

Exhaust shaft 103. . Total ........... Mine 2: 

1 25:2 1-f 2y6 

Exhaust shaft 2-1.. 

Exhaust shaft 2-2.. - I 2 / 1 

Exhaust shaft 2-3.. 

Total ........... 1 31:3 

Mine 3: 

Exhaust shaft 3-1.. 

Exhaust shaft 3-2. . Exhaust shaft 3-3. . To ta 1. .......... 29.2 25.9 3.3 

Peak concentration tration 

Time after 1 Ppb after 1 

release, min hour, 

CONCLUSIONS 

The SF, tracer gas has shown itself to be a useful and versatile tool for 

studying mine ventilation systems . The Bureau of Mines has successfully 

employed SF, to measure and identify ventilation problems such as air leakage 

through old stopes, doors, and cracks; air recirculation caused by leakage and 

cooling plants ; airflow rates in airways of large cross sections and low velocities; air exchange rates in poorly ventilated areas; and air transit times 

underground. The simplicity and accuracy of the tracer gas technique in 

studying ventilation systems where conventional methods fail warrants serious 

consideration of adopting the tracer gas as a standard ventilation tool. 
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Clemens, C. A., and A. P. Altshuller. Response of Electron-Capture 

Detector to Halogenated Substances. Anal. Chem. v. 38, 1966, 

pp. 133-136. 

Clemens, C. A., A. I. Coleman, and B. E. Saltzman. Concentration and 

Ultrasensitive Chromatographic Determination of Sulfur Hexafluoride 

for Application in Meteorological Tracing. Environ. Sci. Tech., v. 2, 

No. 7, 1968, pp. 551-556. 

Collins, G. F., F. E. Bartlett, A. Turk, S. M. Edmonds, and H. L. Mark. 

A Preliminary Evaluation of Gas Air Tracers. J. Air Pollution Control 

Assoc., v. 15, 1965, pp. 109-112. 

Drivas , P. J., P. G. Simmonds, and F. H. Shair. Experimental Characterization of Ventilation Systems in Buildings. Environ. Sci. Tech., v. 6, 

No. 7, 1972, pp. 609-614. 

Hunt, A. E., and H. A. W. Moore. Private communication, 1971. Available 

upon request from A. E . Hunt, Bureau of Mines , Morgantown , W . Va . 

Lester, D., and L. A. Greenberg. The Toxicity of Sulfur Hexafluoride. 

Arch. Ind. Hyg. and Occupational Med., v. 2, 1950, pp.348-349. 

Niemeyer, L. E. , and R. A. McCormick. Some Results of Multiple-Tracer 

Diffusion Experiments at Cincinnati. J. Air Pollution Control Assoc., 

v. 10, 1968, pp. 403-405. 

Rennick, G. E., J. Pasini 111, F. E. Armstrong, and J. R. Abrams. 

Demonstration of Safety Plugging of Oil Wells Penetrating Appalachian 

Coal Mines. BuMines TPR 56, 1972, p. 6. 

Saltzman, B. E., A. E. Coleman, and C. A. Clemens. Halogenated Compounds 

as Gaseous Meteorological Tracers. Anal. Chem., v. 38, 1966, 

pp. 753-758. 

Thimons, E. D., R. J. Bielicki, and F. N. Kissell. Using Sulfur Hexafluoride as a Gaseous Tracer To Study Ventilation Systems in Mines. 

BuMines RI 7916, 1974, 22 pp. 

Turk, A. , S. M. Edmonds, H. L. Mark, and G. F. Collins. Sulfur Hexafluoride as a Gas-Air Tracer. Environ. Sci. Tech., v. 2, No. 1, 1968, 

pp. 44-48. 

Whisman, M. L. Private communication, 1972. Available upon request from 

M. L. Whisman, Bureau of Mines, Bartlesville, Okl??.