The Carbon Quandary: Essential and Detrimental - Sustainable Design: The Science of Sustainability and Green Engineering - page 289

Figure 7.7 Sectional view of
cross-measure methane-drainage
holes in a coal mine ventilation
system.
From A. C. Smith, W. P. Diamond, and
J. A. Organiscak, “Bleederless
ventilation systems as a spontaneous
combustion control measure in U.S.
coal mines,” Information Circular 9377,
NTIS PB94-152816, U.S. Department of
the Interior, Bureau of Mines,
Washington, DC, 1994; B. R. McKensey
and J. W. Rennie, “Longwall ventilation
with methane and spontaneous
combustion: Pacific Colliery,”
Proceedings of the 4th International
Mine Ventilation Congress , Brisbane,
Australia, July 3-6, 1988, Australia
Institute of Mining and Metals,
Melbourne, Australia, 1988, pp.
617-624.

49.7 m

35.1 m

30°

KEY
Cool bed 35°

Mined-out area

Cross-measure
methane-drainage
holes

35.1 m Height above

mined cool bed

7.63 m

1.47 m

year. Estimates put India's coal mine fire releases to be about 50 million metric
tons. This accounts for as much as 1% of all carbon greenhouse releases. This is
about the same as the CO 2 released by all the gasoline-fuel automobiles in the
United States. Engineering solutions that reduce these emissions would actively
improve the net greenhouse gas global flux.
The United States has a checkered history when it comes to coal mine fires.
Some have burned for more than a century. Intuitively, putting out such fires may
seem straightforward. For example, we know that combustion depends on three
components: a fuel, a heat source, and oxygen. All three are needed, so all we
have to do to smother a coal fire is to eliminate one of these essential ingredients.
Unfortunately, since the fire is in an underground vein, fuel is plentiful. Actually,
the solid-phase coal is less of a factor than the available CH 4 , which is ubiquitous
in coal mines. And like the “whack-a-mole” game, the avenues of access to the
fire mean that the heat source is available in different channels. When one is
closed off, another appears.
So that leaves us with depriving the fire of O 2 . This is much easier said than
done. In fact, engineering has been an outright failure in this regard. Flooding the
mines is ineffective, since the fire simply finds alternative pathways in the leaky
underground strata. Excavation has to be almost 100% to be effective. Flushing
with slurries has the same problems. In fact, miner safety and postignition fire
suppression can be seen as competing factors in mining. To ensure sufficient oxy-
gen levels and low toxic gas concentrations, a mine's ventilation system requires
methane-drainage holes to control methane at the face. In many abandoned
mines, cross-measure holes (see Fig. 7.7) were the most common types. These
systems are one reason that oxygen remains available to a fire. 3