Page 227 - Advanced Mine Ventilation
P. 227
Respirable Dust Sampling and Measurement 207
Table 12.8 The Variation of Quartz Percentages in Respirable Dust Samples on Consecutive
Working Days
Quartz Percentage
Mine A Mine M Mine C Mine N Mine G Mine O Mine K
3.39 0.2 5.77 5.93 14.3 8.0 1.0
3.10 4.05 4.80 4.78 10.2 3.5 1.2
2.88 3.91 2.14 7.00 7.0 3.4 0.9
19.88 3.84 3.75 10.35 13.6 5.8 0.9
17.85 2.88 9.69 5.25 11.7 1.7 1.1
3.75 16.2 0.0 2.1
0.3 3.4
0.0 3.0
0.0 4.0
0.8 0.6
Table 12.9 The Minimum Number of Samples Needed
to Obtain a Quartz Percentage Within 20% of the Mean
Value at a 90% Confidence Level
Mine Number of Samples
A 46
M 13
C 16
N 6
G 5
O 86
K 28
12.6 Threshold Limits for Various Dusts Prevailing in
Mines
Besides coal, silica, and DPM (diesel particulate matter), there are other dust clouds in
mines that can create a health hazard. The American Congress of Governmental Indus-
trial Hygienists (ACGIH) has set a threshold limit value (TLV) for each of them. A
short list is provided in Table 12.10 to illustrate the relative pathogenicity of various
dust particles.