Geology Reference
In-Depth Information
Figure 6.1.5. Fire in an open cast coal mine located in the Jharia coalfield, India. Miner
s slums are visible along
the top of the hill, where children play and people live with constant exposure to coal-fire gas. Photo by Prasun
Gangopadhyay, 2006.
'
in Boulder, Colorado, JCF fires contribute to atmospheric sulfate aerosols derived from industrial emissions. These
aerosols absorb or scatter solar radiation, thereby reducing the amount of sunlight that reaches earth
s surface. This
amounts to as much as a 15% reduction for the Indian subcontinent (Collins, 2000; Perkins, 2001).
'
Several forms of technology have been used to investigate JCF fires. Multispectral and temporal data from the
Landsat Thematic Mapper (TM), for example, reveal that subsurface fires are more extensive than surface fires
(Prakash et al., 1997). Surface thermal anomalies (25.6
-
31.6°C) detected with TM-6 thermal infrared data signify
subsurface fires at depths of 45
55 m (Saraf et al., 1995; Prakash et al., 1997). Alternatively, subpixel estimates
using TM-5 and TM-7 short-wave infrared data reveal surface fires ranging in temperature from 342
-
C.
IR pointing thermometers and ground-based thermal detectors confirm such surface fire temperatures (Prakash and
Gupta, 1999). In addition to remotely acquired TM data, BCCL (2003) has integrated GPS data into a Geographic
Information System (GIS) to locate, map, and monitor surface fires, ground subsidence, and borehole temperatures.
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In the JCF, the population density is much higher than in the coalfields of northern China (Prakash, 2003), thereby
necessitating the relocation of large communities of people from endangered regions to newly constructed town-
ships in noncoal-producing areas. Fortunately, the Ministry of Coal and the Government of India have provided
some relocation funds for this purpose (BCCL, 2003).
Once highly problematic coal fires in the JCF are identified with the available technology, a number of techniques
are used to contain or extinguish them. For surface fires, these include trenching, analogous to a forest firebreak,
and surface sealing with soil or some other noncombustible material to cut off oxygen from the fire. Inert gas
injection, sand
bentonite slurry flushing, and surface sealing have been used for subsurface fires. In spite of the
success with these techniques, the fires continue to burn in large areas where subsidence and inaccessible under-
ground workings present a high risk and impasse to firefighters (BCCL, 2003).
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Discussion
R
egardless of origin, coal fires consume a valuable natural resource and constitute a thermodynamic recipe for
environmental catastrophe. Fires in China, Pennsylvania, and India exemplify this. Industrial smokestacks and
motorized vehicles are usually cited in the news as the primary sources of pollution including acid rain and
greenhouse gases. The enormous amount of toxic gases and particulate matter emitted by coal fires burning around
the world over many years contributes significantly to the global destruction of the environment and the health of
