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Pyrite problems in the coal mining industry.

Miron Y

Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, IC 9381, 1993 Sep; :1-13

https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/PB94161866.xhtml

10004957

The presence of pyrite (FeS2) in coal can cause or contribute to several problems for the coal mining industry. These problems, which include spontaneous combustion, roof falls, floor heave, and accidental explosions in coal surface mining when ammonium nitrate-fuel oil (ANFO) explosives are used, result from pyrite oxidation. Pyrite oxidizes exothermically in the presence of air and moisture to form a large variety of products, including hydrated ferrous and ferric sulfates, and sulfuric acid. Some of the products are reactive chemicals and strong oxidants. The volume of many of these oxidation products exceeds the original volume of the pyrite; as a result, the adjacent coal disintegrates and its surface increases, rendering it more susceptible to oxidation. The heat from pyrite oxidation raises the temperature of the adjacent coal, accelerating the oxidation and self-heating rates of the coal. Additional hazards are fires or explosions caused by the frictional ignition of methane when the pyrite in the coal is struck by a cutting bit during mining.

Chemical-reactions; Reaction-kinetics; Spontaneous-combustion; Underground-mining; Mine-safety; Coal-mining; Explosions; Mineral-industries; Soil-and-rock-mechanics

19930901

Information Circular

1993

PB94-161866

A03

IC 9381

PRC

Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, IC 9381

PA