Coal Fires: An Environmental Hazard Gaurav Chakrabarty Msc Geo-informatics, BIT Mesra, Ranchi Abstract Coal fires burning around the world are an environmental catastrophe characterized by the emission of noxious gases such as carbon monoxide, carbon dioxide, sulphur dioxide and nitrogen oxides, particulate matter, and condensation by-products. Underground fires ignited by natural causes or human error are responsible for atmospheric pollution, acid rain, perilous land subsidence, and increased coronary and respiratory diseases. They consume a valuable energy resource, destroy floral and faunal habitats, and promote human suffering as a consequence of heat, subsidence and pollution. This paper provides a brief overview of the deadly impacts of coal fires on the environment, discusses some of the largest coal fires in the world and finally it deals with remote sensing technology used for detecting and preventing coal fire. (Key words: coal fires, environmental problems, Jharia coalfield, Remote Sensing) Introduction to Coal Fire Coal fires are an environmental and economic problem of international magnitude (Figure 1). Coal fires occur in many
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Coal Fires: An Environmental HazardGaurav Chakrabarty
Msc Geo-informatics, BIT Mesra, Ranchi
Abstract
Coal fires burning around the world are an environmental catastrophe
characterized by the emission of noxious gases such as carbon monoxide, carbon dioxide,
sulphur dioxide and nitrogen oxides, particulate matter, and condensation by-products.
Underground fires ignited by natural causes or human error are responsible for
atmospheric pollution, acid rain, perilous land subsidence, and increased coronary and
respiratory diseases. They consume a valuable energy resource, destroy floral and faunal
habitats, and promote human suffering as a consequence of heat, subsidence and
pollution. This paper provides a brief overview of the deadly impacts of coal fires on the
environment, discusses some of the largest coal fires in the world and finally it deals with
remote sensing technology used for detecting and preventing coal fire.
the oxidation reaction in coal becomes self sustaining and spontaneous combustion
occurs varies depending on the type (nature and rank) of coal and surrounding conditions
of heat dissipation. In poor quality coal and where the heat retention is high the coal and
carbonaceous material may start burning at temperatures as low as 30-40° C.
According to US department of energy, many spontaneous fires start in storage
facilities including open air stock piles, coal bunkers, and silos. The DOE attributes
combustion to numerous factors. These include improperly loaded and compacted storage
facilities that promote the diminution of coal into highly combustible fines and also
storage for prolonged period of times, which promotes exothermic oxidation reactions in
high sulfur coals. The major reasons for occurrence of coal fire due to spontaneous
combustion are:
Thick coal seam
Plenty of coal mines in the goaf
Presence of contiguous seams
Coal handling procedures allowed for long-time retention of coal which increases
the possibility of heating.
New coal added on top of old coal created segregation of particle sizes, which is a
major cause of heating.
Too few temperature probes installed in the coal bunker resulted in an excessive
period of time before the fire was detected.
Failure of equipment needed to fight the fire (drag chain conveyer).
Ineffective capability and use of carbon dioxide fire suppression system.
Delay in the application of water.
Inadequate policies, procedures, and training of personnel which prevent proper
decision making, including the required knowledge to immediately attack the fire.
Failure to learn lessons from past occurrences from coal bunker fires.
Effects of Coal Fire
Frankly saying it’s a disaster. Coal fires burning around the world are an
environmental catastrophe characterized by the emission of greenhouse gases (methane,
volatile matter and carbon dioxide) noxious gases, particulate matter, and condensation
by-products. Underground mine fires ignited by natural causes or human error are
responsible for atmospheric pollution, acid rain, perilous land subsidence, and increased
coronary and respiratory diseases. They consume a valuable energy resource, destroy
floral and faunal habitats, and promote human suffering as a consequence of heat,
subsidence and pollution (Whitehouse and Mulyana 2004). Field measurements and
laboratory analysis reveal that during burning, these fires spew carbon monoxide,
benzene, toluene and dozens of other toxins into the atmosphere and soil, along with the
greenhouse gases methane during heating of the coal and carbon-dioxide. The per-annum
global emissions of the components in the coal fire gas have never been quantified.
However the toxins have made people sick, sometimes even proved fatal.
The various components like acids, aerosols, and toxic particles released from
coal fires may be transported to distant places. For instance, in China such pollutants
have affected adversely 88 cities. Similar sulfate aerosols released from fires of mines in
Jharia, India, have reduced the intensity of solar radiation reaching the Indian
subcontinent by 15% (Stracher & Taylor, 2004).
Following are some of the pictures (Figure 2a to 2f) illustrating coal mine fires
around the world:
(a) (b)
(c) (d)
(e) (f)
Figure 2: Typical coal fires in the mining regions around the world
Source: (a) Northern China (http://www.ehponline.org/docs/2002/110-5/tirelava.jpg); (b) Wuda Region in North Central China (Kuenzer, C. et al., 2007); (c) Olyphant,
Pennsylvania, USA (http://www.undergroundminers.com/olyphantfire31.JPG); (d) USA (http://www.centraliaminefire.com/archive.html) ; (e) Jharia, India (Stracher, G. B.,
2007); (f) Jharia, India (Stracher, G. B., 2004).
On the other hand, according to Glen B. Stracher, coal fires have some
constructive effects in the sense that they transform landscapes, frequently generating
new chemical products at the same time. Sinkholes, valleys, and slump blocks produced
by volume-reduced coal during burning, chemically altered or pyro-metamorphic rocks
and paralavas are the most obvious features of modern fires.
Several direct and indirect impacts due to coal fires on environment can be listed
as below:
1. Emission of noxious gases like CO, NOX & SOX and the particulate matter
that pollute the local atmosphere,
2. Emission of greenhouse gases such as CO2, and CH4 further aggravating
the global warming problem,
3. Loss of non-renewal valuable resources that has become life-line of every
individual in modern times,
4. Loss of flora and fauna,
5. Subsidence causing damage to life and properties as well as change in the
local drainage pattern,
6. Air pollution problem,
7. Land degradation,
8. Temperature increment of surrounding areas and
9. Increase in production cost due to deployment of man, money and
machinery for fire estinguishing and difficulties in mining operations.
Largest Coal Fires in the World: Some Cases
Some of the largest and oldest coal fires in the world are dealt below:
ChinaChina leads the world in coal production. Its reserves are concentrated in the
Xinjiang Uygar and Ningxia Hui of north-west and north-central China respectively. Coal
fires burning throughout these regions and across northern China started by lightening,
spontaneous combustion and mining operations on all scales. The coal fires in China is
consuming up to 200 millions tons of coals per year and accounts for 2-3% of the annual
world emissions of atmospheric CO2 from burning fossil fuels (Figure 3) (Discover,
1999).
Figure 3: Coal Fire in Northern China
(Source: Gangopadhyay, P. K. and Dutt-Lahiri, K., 2005)
In the Rujigou coalfield of Ningxia, underground coal fires are responsible for
land subsidence and the release of hydrogen sulfide into the atmosphere (Discover,
1999). The length, width and depth of the surfacial cracks induced by subsidence are as
much as several kilometers long, tens of meters wide, and hundreds of meters deep.
These cracks promote subsurface burning by providing a conduit through which oxygen
can circulate to support combustion (Figure 4).
Figure 4: A collapsing coal seam burns in an open pit mining area in the Rujigou Coalfield in China
Following pictures (Figure 9) provides a glimpse of the catastrophic coal fire in
Kusunda area of Dhanbad district:
(a) (b) (c)
Figure 8: A Glimpse of the Catastrophic Coal Fire in Kusunda Area of Dhanbad District
(Source: Author)
The above three pictures are taken in Kusunda coal field area where open cast
mining is going on. The area is really under fire and the persons working over there have
life-risks. Smokes are coming out from the mine overburden dumps too which includes
many noxious gases, toxic fly ash that pollute air, water, and soil which ultimately are
promoting human diseases of heart and lungs. Following pictures (Figures 10a to 10c)
shows the smokes puffing out of mine overburden dumps in Kusunda and the surface
temperature problem faced by the worker there.
(a) (b) (c)
Figure 10: Smoke and the Hot Surface problems faced by the people in Kusunda. (a) Smoke in the Overburden Dumb and (b & c) Vapour Formation after water is
sprinkled to cool the hot surface for workers to work there(Source: Author)
The According to National Center for Atmosphere Research 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 the earth’s surface (Collins 2000).
Singh et al. (2007) have studied mine fire indices and their application to Indian
underground coal mine fire. Stracher and Taylor (2004) have also studied Jharia coal fire
problem in detail. Figure 11 and Figure 12 show yet another coal fires in Jharia
Coalfields. From the Figure 11 one can see how in the midst of extreme danger workers
carry out the mining activities and Figure 12 shows the efforts being made to fight the
coal fire in the Jharia region using crude techniques.
Figure 11. Coal mining efforts in the midst of extreme danger and minimal mining profits. (Source: Michalski, 2004)
Figure 12: Crude techniques for combating coal mine fires in the Jharia Coalfield. (Source: Michalski, 2004)
Detection of Mine Fire using Remote Sensing Technology
To prevent the coal mine fire from damaging life and property, we got to identify
it first and the direction in which it is spreading. To detect and identify the mine fire we
can use the remote sensing techniques (Chatterjee 2006, Prakash et al., 1995, Reddy et al.
1993 and Bhattacharya 1991)). Researchers such as Slavecki, 1964, Knuth et al., 1968
Knuth, 1968 and Green & Moxhani, 1968 and others throughout the world have tried to
make use of thermal infrared imagery to detect subsurface coal fires. Subsidence has been
identified due to underground mine fire in northwest China using Thermal, Microwave,
and optical satellite data (Prakash et. al. 2001). Research using synthetic aperture
RADAR (SAR) to identify subsidence is currently being conducted at ITC (Prakash,
2003). Optical and thermal images acquired by the Beijing Remote Sensing Corporation
(BRSC) and heat measurements from surface and subsurface detectors have been used to
determine the coal fire size, depth of greatest intensity, and burning direction (Vekerdy
et. al 1999). Temperatures exceeding 8000C for surface fires have been recorded with
ground based thermal detectors. Combining the information acquired for numerous fires
with GPS and geologic data, ITC scientists together with BRSC designed a PC-based
geographic information system COALMAN (Vekerdy et, al. 2000). COALMAN is used
to assist Chinese fire fighters in the field by generating a time series of fire fighting maps
and subsurface images of fire.
In Jharia, several forms of technology have been used so far to investigate mine
fires. Some of the measures for controlling coal fires in Jharia coalfields include, bull
dozing, leveling and covering with soil and overburden dumps to prevent the entry of
oxygen and to stabilize the land for vegetation. Use of sand as stowing material for filling
the vacant spaces in the abandoned mines so as to stop the entry of oxygen and also to
prevent the subsidence is another method being used in the Jharia region. Nowadays, fly
ash is being experimented and used as a stowing material.
However, use of Remote Sensing and Geographical Information System is the
latest method that is being used to identify and understand the fire problems of Jharia
Coalfields. Multi-spectral and temporal data from the LANDSAT Thematic Mapper
(TM), reveal that subsurface fires are more extensive than surface fires (Prakash et. al
1997, Prakash et al. 1999). Surface fire anomalies detected with TM-6 thermal infrared
data signify subsurface fires at depths of 45-55m (Saraf et. al 1995). Alternatively, sub-
pixel corrections for TM-5 and TM-7 short wave-infrared data reveal surface fires
ranging in temperature from 342 to 7310C. In addition to remotely acquired TM data,
BCCL has integrated GPS data into a GIS to locate, map, and monitor surface fires.
Conclusion
Coal fire is a catastrophe in true sense, endangering life, property and the
resources itself. Whether, we pick up the case of china, Pennsylvania or India (Jharia),
just three words flashes in our brain- death, decay and destruction. The impacts of coal
fire come into picture with toxic gases, subsidence, particulate matters, destruction of
floral and faunal habitats and many more including the loss of invaluable non-renewal
resources. In short, coal fire is affecting air, water, soil and the entire ecosystem and
therefore, should be controlled at the earliest in order to prevent any major disaster in the
near future. Surface and sub-surface coal fires are a widespread problem of international
magnitude. Such problems need to be addressed more seriously as several environmental
and economic problems are directly linked to it. In fact, in the present time remote
sensing technique can prove to be an effective tool in detecting and monitoring coal fires
and perhaps in checking huge economic loss and environmental disasters.
References
Banerjee, S.C., 1985, Spontaneous Combustion of Coal and Mine Fires. A.A. Balekema,