Geology Reference
In-Depth Information
9.2 Sample Collecting and Field
Data
Glenn B. Stracher (left) and Steve Renner,
South Can˜ yon Number 1 Coal Mine Fire,
Glenwood Springs, Colorado.
From Stracher (2003) with modifications, reprinted with permission of the Center for Applied Energy Research,
University of Kentucky, Lexington. Photo by Janet L. Stracher, 2004.
Introduction
W
herever coal is strip (open pit) or deep mined, the potential for fire exists. Coal fires associated with the abandoned
workings or workings of coal mines are reported from mining areas around the world (Prakash et al., 1999; Stracher
and Taylor, 2004). Surface expressions of underground coal fires observable in the field include baked rocks, areas of
dead vegetation, land subsidence, and gas vents and fissures (Stracher, 1995; Gupta and Prakash, 1998).
Coal-fire gas exhaled from vents and fissures and minerals derived form cooling gas reveal important information
about the chemical composition of burning coal and the possible interaction of the gas with rock and water on its
way to the surface prior to exhalation. The chemistry of these minerals and the exhaled gas is reflective of elements
and compounds that may be released as pollutants into the atmosphere, soil, streams, or ground water. Such
pollutants may be responsible for a variety of environmental and human health problems including the destruction
of floral and faunal habitats (Stracher, 2002; Stracher and Taylor, 2004), stroke and pulmonary heart disease (World
Resources Institute, 1999, pp. 63
67), and arsenosis and fluorosis (Finkelman, 2001). Consequently, the study of
coal-fire gas and associated minerals can be critically useful in understanding environmental pollution problems
associated with coal-mine fires.
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Safety Precautions
S
afety precautions are essential in the field when collecting minerals derived from coal-fire gas or the gas itself.
The most dangerous impediments when sampling from active vents and fissures are toxic vapors, heat, and
subsidence. Figure 9.2.1 illustrates all three of these at the southern end of Centralia, Pennsylvania. The Centralia
mine fire began in and has been burning since 1962, when an abandoned strip-mining cut was ignited to reduce its
volume and control rodents. The Buck Mountain anthracite seam in the landfill ignited and the fire spread to
abandoned underground coal mine tunnels (DeKok, 1986, p. 20; Geissinger, 1990). For safety, it is best to never
collect alone. In addition, a walking stick used to test the ground ahead of oneself while heading toward a vent or
fissure is a wise precaution against subsidence. One should never venture, even with a field assistant and gas mask,
into an area completely engulfed in smoke like the valley in the upper right-hand corner of Figure 9.2.1. The
consequence of becoming disoriented could prove fatal. Once a vent or fissure is found with material worthy of
collection, gloves may be necessary to avoid getting burned when working at or near the collection site
(Figure 9.2.2). Extreme caution is necessary to avoid breathing as much coal gas as possible, and a gas mask
should be worn where fresh air is not immediately nearby or when sampling requires an extended period of time
surrounded by toxic vapors. I have recorded temperatures and collected gas and gas-associated minerals from vents
and fissures by holding my breath (Figure 9.2.2) and then
after moving to a location several
meters away with adequate ventilation. For safety sake, someone was always standing nearby to watch my
activities. This is advisable because the temptation to breath and doing so while collecting data could be dangerous
while surrounded by thick smoke and toxic gas. Consequently, I wear a gas mask now when I must work close to a
vent.
“
coming up for air
”
