Atmosphere and temperature within a reclaimed coal-stripmine and a numerical simulation of acid mine drainage from stripmined lands
Oxygen, O/sub 2/, and carbon dioxide, CO/sub 2/, and temperature were measured with depth along a transect of an acid, reclaimed coalstripmine over a two-year period. Most of the mine remains well oxygenated (O/sub 2/>10% by volume) down to 12 meters depth. At some locations, especially within 2 meters of the surface, variations in O/sub 2/ and CO/sub 2/ are correlated with changes in the spoil temperature. Spoil temperatures in layers below 3 meters remain in a range conductive to iron-oxidizing bacterial activity year around. Flux ratios of CO/sub 2/ and O/sub 2/ and source/sink rates of the two gases indicate that carbonate neutralization of the acid produced by pyrite oxidation is the dominant source of CO/sub 2/. In a second phase of the study, a numerical model describing the production and removal of acid and acid by-products from reclaimed coal stripmines is presented. Both direct oxygen and bacterially catalyzed pyrite oxidation was considered. Under all conditions modeled, excess acid, in the form of free hydrogen, must be removed if bacteria are to play an important role in accelerating pyrite oxidation. Leaching of the spoil by normal precipitation is insufficient in removing the excess hydrogen ion. Neutralization and buffering by the host rock are required for prolonged bacterial activity--the degree of hydrogen ion removal determining the maximum sustainable activity. At optimum conditions bacteria can greatly increase pyrite oxidation.
- OSTI ID:
- 5228859
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACID MINE DRAINAGE
MATHEMATICAL MODELS
SPOIL BANKS
GASES
TEMPERATURE MEASUREMENT
SURFACE MINING
BACTERIA
CARBON DIOXIDE
COAL MINES
LAND RECLAMATION
NUMERICAL ANALYSIS
OXYGEN
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
FLUIDS
MATHEMATICS
MICROORGANISMS
MINES
MINING
NONMETALS
OXIDES
OXYGEN COMPOUNDS
UNDERGROUND FACILITIES
010900* - Coal
Lignite
& Peat- Environmental Aspects