Hidden Coal Fires Create Visible Problems
DENVER, Colorado, February 14, 2003 (ENS) - Fires are blazing in underground coal seams around the globe, sending tons of soot, toxic fumes and greenhouse gases into the atmosphere. These fires can burn unchecked for decades, but researchers speaking at a scientific meeting today say new techniques offer hope for extinguishing the blazes.
Major underground fires are burning in all of the world's coal producing nations, with the worst blazes found in countries such as China, India and Indonesia. Smaller fires - some of them decades old - are also burning in areas of the United States including Colorado and Pennsylvania.
These fires threaten the environment and human health, scientists said today at the American Association for the Advancement of Science (AAAS) Annual Meeting in Denver. 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."
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.
"These ultra-hot fires can occur naturally, when oxidation reactions promote spontaneous combustion. However, they are frequently caused by humans. For example, during mining, coal seams can be ignited by sparks from cutting and welding, electrical work, explosives or even cigarette smoking."
In China, small illegal mines are ablaze across the northern region of Xinjiang. Local miners often use abandoned mines for shelter, and may burn coal within the shafts for warmth.
Besides fires in coal mines, burning coal may also be located in coal waste piles or natural coal seams, often ignited by heat from above ground fires set to clear the landscape for farming.
One of the worst underground fires in the United States, the Centralia, Pennsylvania mine fire, has been burning since May 1962. The fire was started when the local city council set trash ablaze in an abandoned strip mine that had been used as an illegal dump.
The fire burned along a coal seam into tunnels located beneath Centralia, sending smoke and toxic fumes in the air and driving out almost all the town's 1,100 residents. A similar fire is now causing problems in Youngstown, Pennsylvania, where the Percy mine fire has been burning for more than 30 years.
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.
A team from the Netherlands studied the environmental effects of underground fires in China, concluding that the fires release up to 360 million metric tons of carbon dioxide each year, equal to two to three percent of global carbon dioxide releases.
While researchers have yet to measure emissions from all coal fires, the large scale burning in coal producing countries may be making a major contribution to global and regional climate change, as well as regional air pollution and human respiratory problems, according to the panelists who spoke today in Denver.
"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 environment impacts of coal fires do not stop with the atmosphere. The release of toxic elements like arsenic, mercury and selenium can also pollute local water sources and soils. As the coal is burned away, the land itself can subside, posing a risk to buildings and changing the routes of streams.
Heat from the fires can kill vegetation above, even igniting forest fires. Last summer, a fire in an underground coal seam in Colorado sparked a blaze that scorched more than 12,000 acres of forest, destroyed two dozen homes, and threatened the resort town of Glenwood Springs.
The underground coal seam that ignited the fire has been burning for about 100 years - it was also responsible for the infamous 1994 Storm King Mountain fire that killed 14 firefighters.
Disasters like these are fueling efforts to fight underground coal fires. One 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, called Thermocell, helps to cut off the fire's oxygen supply and allow the blaze to cool down.
While traditional coal fire fighting techniques require large equipment used close to the red hot fire, the readily flowing grout can be pumped from a distance away," said Goodson and Associates owner Gary Colaizzi. Experts could also inject the grout into cracks, vents or excavated trenches to seal off the fire and prevent its spread, Colaizzi added.
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, van Dijk said.
Another collaboration, involving 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 already, but he estimates that many more are still burning.
"What went up in smoke in Indonesia makes it one of the worst polluters in the world," said Whitehouse.
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, Whitehouse added.
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