Geology Reference
In-Depth Information
exposure to mobilized-trace elements may account for the occurrence of lung and skin disease in people living near
the Jharia coalfield fires in India.
Toxic elements in native form or in minerals nucleated at the surface from coal-fire gas exhaled at vents and ground
fissures, especially if in a water-soluble phase, may present a threat to ecosystems and to human health (see below).
However, not all of the harmful elements precipitate on the surface. Large amounts of potentially toxic gases are emitted
into the atmosphere. Kuenzer et al. (2007) note that the gases released from the fires in north-central China are rich in
CO, CO
2
and other greenhouse-gases, methane (CH
4
), sulfur dioxide, nitrous oxides, and toxic gases H
2
SandN
2
O.
Estimates of the contribution of CO
2
from the coal fires in China alone range as high as 2
3% of the total world CO
2
production due to fossil fuels (International Institute for Geo-Information Science and Earth Observation, 2009). If true,
the fires would be one of the largest sources of this greenhouse gas and a major contributor to global climate change.
-
According to a study by Pone at al. (2007), gases emitted from burning-waste piles in the Witbank and Sasolburg
coalfields of South Africa were found to contain part per million levels of the toxins toluene (5.2
-
397), benzene
-
-
(6.6
5.9) as well as lesser amounts of many other volatile organic compounds. CO
2
levels
ranged from almost 1% to more than 3% by volume of the gases generated by the fires in these coalfields.
50), and xylene (0.1
In the Eastern Kentucky coalfield near the towns of Hazard and Bulan, gas exhaled from vents and ground fissures
in sandstone; associated with an underground coal fire in the Pennsylvanian Hazard No. 7 coal bed, transformed
upon cooling into creosote deposits overlain by a dusting of sulfur and salammoniac (NH
4
Cl) adjacent to the vents
and fissures (Stracher et al., 2008). Gas analyses revealed 47 compounds including the toxins toluene and xylene;
greenhouse gases CH
4
and CO
2
; and the potential ozone-forming gases ethene, ethane, propene, and propane, all
emitted from the vents (165
385°C) into the atmosphere. Analysis of the creosote revealed the presence of
pyrogenic polycyclic aromatic hydrocarbons (Emsbo-Mattingly et al., 2008). The solid by-products of combus-
tion could present a potential health hazard as soil and water pollutants.
-
Mercury may be another potential environmental and human-health problem caused by coal fires. Mercury-bearing
minerals are uncommon around gas vents and ground fissures but this may be because mercury is so volatile that it
does not precipitate from the gas. Assuming a conservative estimate that about 200 million tons of coal are
consumed annually by uncontrolled coal fires worldwide, Pirrone et al. (2009) estimate that this would release
about 32 tons of mercury into the atmosphere or nearly only about one-third less than the 48 tons of mercury
released by the roughly one billion tons of coal burned in the United States every year for generating electricity
(U.S. Environmental Protection Agency, 1997).
According to Rosema et al. (1999) 100 to 200 million tons of coal are lost each year due to coal fires in China.
However, more recent studies report that 20 million tons of coal are being burnt in uncontrolled coal fires in China
each year and about 200 to 300 million tons of coal are lost in China each year, because the fires hinder the
accessibility for mining operations in their surroundings (Voigt et al., 2004).
Unfortunately, there is no comprehensive assessment of the amount of coal consumed worldwide per annum by
coal-bed, coal-waste, and coal-stockpile fires. The 200 million ton estimate noted above would represent an
enormous loss of a valuable energy resource. If this estimate is reasonably accurate, it means that about 3% of all
the 6.5 billion tons of coal burned annually each year is lost to uncontrolled coal fires and that these uncontrolled
fires are consuming more coal than do all but the five largest coal consuming countries: China, Germany, India,
Russia, and the United States (Energy Information Agency, 2009).
Discussion
U
ncontrolled fires in underground coal mines and coal waste piles present a range of environmental and human-
health hazards. In consuming large quantities of a valuable energy resource, these fires destroy the local ecosystem,
pollute air and water, emit large volumes of greenhouse and toxic gases, and put at risk the health of coal miners
and people living in nearby communities. Unfortunately, the health problems have been poorly studied. Finkelman
(2004) offers several explanations for the lack of epidemiological studies. These include:
The gross environmental devastation may have deflected attention from the health problems;
The manifestations of the health problems may be quite subtle;
