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A Global "Catastrophe" Coal Fires
Threaten Environment, Human Health
Major underground fires are blazing in the world's coal-producing nations, threatening the environment and human health, scientists said today at the American Association for the Advancement of Science (AAAS) Annual Meeting. Although some coal fires can be impossible to extinguish, new technologies provide hope that experts may someday be able to control them, if not put them out altogether.
"Coal fires are a global catastrophe," said Glenn Stracher of East Georgia College. But, surprisingly few people know it, he added.
"For most people who don't live near one of these fires, it never reaches them," Stracher said. "There may be a little clip in the newspaper, but most people aren't aware of the extent of the problems involved in these fires."
The coal fire problem is most severe in countries such as China, India, and Indonesia, although smaller fires are still burning in the United States, for example in Colorado and Pennsylvania.
According to Stracher's forthcoming article in the International Journal of Coal Geology, scientists have determined that coal fires in China consume up to 200 million tons of coal per year. For comparison, coal consumption in the United States during 2000 was just over one billion tons, according to the U.S. Department of Energy. (Please see the website, http://www.eia.doe.gov/cneaf/coal/statepro/imagemap/us1p1.html.)
The Hazards of Coal Fires
These ultra-hot fires can occur naturally the right combination of sunlight and oxygen can cause spontaneous combustion but they are frequently caused by humans. In these cases, the burning coal may be located either in abandoned mines or waste piles, or in coal seams, ignited by heat from above-ground fires set to clear the landscape for farming.
Once underway, coal fires can burn for decades, even centuries. In the process, they release large volumes of greenhouse and noxious gases and soot particles into the atmosphere.
While researchers have yet to measure coal fires' emissions, the large-scale burning in coal producing countries may be making a significant contribution to global and regional climate change, as well as regional air pollution and human respiratory problems, according to the panelists.
"One way to deal with greenhouse emissions limits may be to stop coal fires," said Paul van Dijk of the International Institute for Geo-Information Science and Earth Observation (ITC), in the Netherlands.
The effects of coal fires don't stop with the atmosphere. The release of toxic elements like arsenic, mercury, and selenium can also pollute local water sources and soils. Heat from the fires can kill vegetation above, even igniting forest fires. The land itself can subside, posing a risk to local infrastructure.
Fighting Back Against Coal Fires
Gary Colaizzi's engineering firm, Goodson and Associates, Inc., has developed a heat-resistant "grout," a mixture of sand, cement, fly ash, water, and foam that can be pumped around burning material. The grout can then cut off the fire's oxygen supply and allow the blaze to cool down.
While traditional coal fire-fighting techniques require large equipment used near the red-hot fire, the readily flowing grout can be pumped from a distance away. Experts could also inject the grout into cracks, vents, or excavated trenches, to seal off the fire and prevent its spread, Colaizzi said.
The grout could even be used to prevent fires, according to Colaizzi, if it were sprayed onto exposed surfaces of coal seams just after strip mining, to seal them from oxygen.
Colaizzi's firm has used its grout on fires in Colorado and Arizona, and discussions are underway about the possibility of using it in China.
Because coal fires are dangerous to approach, and typically burn underground, predicting where they will spread has been a major challenge, especially in remote areas like northern China.
In collaboration with the Chinese government, van Dijk and his colleagues have used a combination of remote sensing data and GIS technology to detect and monitor coal fires in the northern regions of the country. Their results are helping researchers explore how these fires evolve and what the best approaches might be for extinguishing them.
Ultimately, these techniques should allow scientists to estimate how much carbon dioxide these fires are emitting, according to van Dijk.
Another collaboration, between the United States and Indonesian governments, developed out of concern over the smoke and haze from forest fires that has affected human health in countries such as Indonesia, Singapore, and Malaysia in recent decades.
The forest fires have caused many coal fires, which in turn can ignite more forest fires, according to Alfred Whitehouse of the Ministry of Energy and Mineral Resources Coal Fire Project. Whitehouse and his colleagues have put out a number of fires in Indonesia thus far, but he estimates that many more are still burning.
Coal fires now threaten some of Indonesia's national parks and a nature preserve that is being used as a reintroduction site for the endangered orangutan, according to Whitehouse.
"What went up in smoke in Indonesia makes it one of the worst polluters in the world," Whitehouse said.
13 February 2003
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