Coal fires can burn for very long periods of time (from months to centuries), until the seam in which they smoulder is exhausted. They propagate in a creeping fashion along mines shafts and cracks. Because they are underground, they are extremely difficult and costly to reach and extinguish. There is a strong similarity between coal fires and peat fires.
Some fires along coal seams are natural occurrences. Some coals may self-ignite at temperatures as low as 40 °C (104 °F) in the right conditions of moisture and grain size. Wildfires (lightning-caused or others) can ignite the coal closer to the surface or entrance, and the smouldering fire can spread through the seam, creating subsidence that may open further seams to oxygen and spawn future wildfires when the fire breaks to the surface. Prehistoric clinker outcrops in the American West are the result of prehistoric coal fires that left a residue that resists erosion better than the matrix, leaving buttes and mesa. It is estimated that Australia's Burning Mountain, the oldest known coal fire, has burned for 6,000 years.
Globally, thousands of inextinguishable mine fires are burning, especially in China and India, where poverty, lack of government regulations and runaway development combine to create an environmental disaster. Modern strip mining exposes smoldering coal seams to the air, revitalizing the flames.
Rural Chinese in coal-bearing regions often dig coal for household use, abandoning the pits when they become unworkably deep, leaving highly combustible coal dust exposed to the air. Using satellite imagery to map China's coal fires resulted in the discovery of many previously unknown fires. The oldest coal fire in China is in Baijigou and is said to have been burning since the Qing Dynasty.
In 2004, the Chinese government claimed success in extinguishing a mine fire at a colliery near Urumqi in China's Xinjiang province that had been burning since 1874. However, a March 2008 Time magazine article quotes researcher Steven Q. Andrews as saying, "I decided to go to see how it was extinguished, and flames were visible and the entire thing was still burning.... They said it was put out, and who is to say otherwise?"
Far East Energy Announces Increase in Production, Gas From a Second Coal Seam, and Gas From a Distant Parameter Well.
Sep 22, 2009; Far East Energy Corporation (BULLETIN BOARD: FEEC) announced that gas production in the Number 15 coal seam of its 1H Pilot Area...
COAL-SEAM FIRES `LIKE A TICKING TIME BOMB' IN TOO-DRY AREAS AT LEAST A DOZEN BURN UNDERGROUND ACROSS COLORADO AT ANY TIME, STATE GEOLOGIST SAYS.(City Desk/ Local)
Jun 10, 2002; Byline: Jim Erickson News Science Writer Coal-seam fires can smolder quietly for decades ``like a ticking time bomb then spark...
Coal Seam Gas CSG/CBM in Asia, 2011 - Market Analysis, Investment Scenario, Competitive Landscape and Production Forecasts to 2015.(Report)
Feb 14, 2012; Research and Markets (httpwww.researchandmarkets.com/research/cf3176/coal_seam_gas_csg) has announced the addition of...