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Pyrite Problems in the Coal Mining Industry.

Authors
Miron-Y
Source
BoM, 1993 Sep :13 pages
Link
NIOSHTIC No.
10004957
Abstract
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.
Keywords
Chemical-reactions; Reaction-kinetics; Spontaneous-combustion; Underground-mining; Mine-safety; Coal-mining; Explosions; Mineral-industries; Soil-and-rock-mechanics;
Publication Date
19930901
Document Type
Information Circular;
Fiscal Year
1993
NTIS Accession No.
PB94-161866
NTIS Price
A03
Identifying No.
IC 9381
NIOSH Division
PRC;
Source Name
Bureau of Mines
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