Gas Vent Mineralization and Coal Combustion - Coal and Peat Fires: A Global Perspective - page 144

Figure 9.2.1. Hazards of collecting coal-fire minerals (sulfur in this case) and gas observed at the southern end of
Centralia, Pennsylvania. Note subsidence around the sulfur vent, extending into the smoke-filled valley in the
upper right corner of the photo. Field of view is ~35 m. Photo by Glenn B. Stracher, 1995.
Figure 9.2.2. Hazards associated with collecting coal-fire minerals and gas. Glenn B. Stracher is holding his
breath to avoid inhaling toxic fumes. Note the insulated leather glove used to protect his right hand during insertion
of a thermocouple temperature probe into a coal-fire vent: adjacent to a closed section of Route 61 on the eastern
end of Centralia, Pennsylvania. The white Teflon ® tube near the bottom of the photo was used to extract gas out of
the vent with a hand pump (see text). Gas temperature was 126.2°C. CO and CO 2 , measured with Dräger tubes,
were highly toxic at 1000 and 2200 ppm, respectively. The nucleation products (probably minerals), associated
with coal-fire gas from this vent; have yet to be identified. Photo by Janet L. Stracher, 2003.
GPS and Temperature Measurements
T wo necessary instruments used to record field data at a gas vent prior to sampling include a handheld Global
Positioning Satellite (GPS) unit for documenting sample location and a high-temperature thermocouple probe
for measuring gas temperature inside the vent. These instruments are easy to learn how to use and are manufactured
by a number of companies. A Pasco ® physics thermocouple probe with a digital temperature display and a
Magellan ® handheld GPS unit are illustrated in Figures 9.2.3 and 9.2.4, respectively. The Pasco ® instrument
consists of a digital gauge to which a high-temperature stainless steel thermocouple probe is attached. The stainless
steel probe is inserted into a gas vent or fissure and once the temperature stops increasing on the digital
display screen of the gauge, the value of the gas temperature is recorded. Similar probes are offered by other
manufacturers.