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Pyrite Problems in the Coal Mining Industry.

PB94161866

Publication Date	1993
Personal Author	Miron, Y.
Page Count	28
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	Pyrite Coal mining Ammonium nitrates Chemical reactions Reaction kinetics Oxidation Spontaneous combustion Explosions Underground mining Coal deposits Heaving Mine safety
Source Agency	Bureau of Mines
NTIS Subject Category	48A - Mineral Industries 81A - Combustion & Ignition 99F - Physical & Theoretical Chemistry 50D - Soil & Rock Mechanics
Corporate Authors	Bureau of Mines, Pittsburgh, PA. Pittsburgh Research Center.
Supplemental Notes	See also PB87-189809. Library of Congress catalog card no. 93-39734.
Document Type	Technical Report
Title Note	Information circular/1994.
NTIS Issue Number	199415

Pyrite Problems in the Coal Mining Industry.

Pyrite Problems in the Coal Mining Industry.
PB94161866

Publication Date	1993
Personal Author	Miron, Y.
Page Count	28
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	Pyrite Coal mining Ammonium nitrates Chemical reactions Reaction kinetics Oxidation Spontaneous combustion Explosions Underground mining Coal deposits Heaving Mine safety
Source Agency	Bureau of Mines
NTIS Subject Category	48A - Mineral Industries 81A - Combustion & Ignition 99F - Physical & Theoretical Chemistry 50D - Soil & Rock Mechanics
Corporate Authors	Bureau of Mines, Pittsburgh, PA. Pittsburgh Research Center.
Supplemental Notes	See also PB87-189809. Library of Congress catalog card no. 93-39734.
Document Type	Technical Report
Title Note	Information circular/1994.
NTIS Issue Number	199415