Page 243 - Advanced Mine Ventilation

Origin of Gases in Coal Mines 221

Table 13.5 Parameters of International Coal Classification Compared to American Standards
for Testing Material (ASTM) Rank

Volatile Matter, Dry, Ash-free Percent
a
International Class ASTM Rank or Btu, Moist, Ash-Free
1A Anthracite 3e6.5
1B Anthracite 6.5e10
2 Semianthracite 10e14
3 Lvb 14e20
4 Mvb 20e28
5 Mvb 28e33
6 Hvab >13,950
7 Hvbb 12,960e13,950
8 Hvcb or Sba 10,980e12,960
9 Sbb 10,260e10,980

Report of Investigations 5435 and Ref. [1] of this chapter.
a
Lvb, low-volatile bituminous; Mvb, medium-volatile bituminous; Hvab, high-volatile A bituminous; Hvbb; high-volatile B
bituminous, Sba, subbituminous A, Sbb, subbituminous B.
Table 13.6 Shows the Dependence of Rank on Ro Values [4]

Coal Rank R o (%) Remarks
Peat/Lignite <0.2 As the rank of coal increases from lignite to
anthracite, generally the carbon content and
Subbituminous 0.2e0.6
calorific value increases but volatile matter
High-volatile bituminous 0.6e1.1 and moisture contents decrease.
Mid-volatile bituminous 1.1e1.5
Low-volatile bituminous 1.5e2.0
Semianthracite 2.0e2.5
Anthracite 2.5e6.0
Met-anthracite 6.0e10.0
Graphite >10.0

13.4.2 CO 2 Percent
It is not very reliable but biogenic methane has less than 5% CO 2 , whereas thermo-
genic coal can contain 2%e15% CO 2 . In some coals in Australia, it can be as high
as 50% by volume.