Page 395 - Advanced Mine Ventilation

364 Advanced Mine Ventilation

Table 22.1 Frictional Ignitions in US Coal Mines (Anthracite Mines Not Included)

States

Year AL CO IL IN KY NM OH OK PA TN UT VA WV Total
1983 23 1 2 11 13 5 4 59
1984 30 3 5 8 2 5 2 9 64
1985 56 3 10 1 5 3 78
1986 25 2 13 4 15 9 69
1987 15 2 3 5 1 8 24 10 16 83
1988 20 2 1 3 13 12 19 5 75
1989 23 6 18 16 13 4 80
1990 33 2 2 16 10 4 17 6 90
1991 62 2 3 2 2 8 3 29 5 116
1992 49 3 8 2 36 5 103
1993 52 2 7 3 9 2 75
1994 43 6 4 1 1 4 3 14 1 77
1995 29 1 1 1 5 1 17 2 57
1996 48 8 12 68
1997 38 2 6 1 11 1 17 3 79
1998 38 1 1 5 5 2 3 55
1999 45 2 1 1 6 13 3 4 1 76
2000 10 1 5 15 8 1 4 44
2001 16 2 2 13 5 10 50
2002 23 2 2 2 13 3 17 60
2003 16 2 5 2 2 11 4 7 9 58
2004 7 3 4 1 22 1 3 9 50
701 21 19 11 62 7 22 2 234 2 113 245 127 1566
Total

3
If the gas content of coal seams exceeds 100 ft /t and mining conditions encounter
sandstone, special precautions should be taken to prevent frictional ignitions. Preven-
tative techniques have been discussed in the literature extensively, but the authors have
mainly emphasized bit design and cutting machine parameters. In view of the progress
made in coal seam degasification, current preventative techniques can be classified, in
order of importance, as follows:
3
1. Coal seam degasification to reduce the seam gas content to less than 100 ft /t.
2. Ventilation to prevent layering of methane.
3. Wet cutting/water-jet-assisted cutting.
4. Machine design to minimize ignitions.