Acid mine drainage from reclaimed coal strip mines. Part 2. Simulation results of model
Acid mine drainage from reclaimed coal strip mines is simulated by use of a comprehensive model described in an earlier paper. The simulated concentrations of key components are well within the ranges of measured values from reclaimed mines. In systems without iron-oxidizing bacteria the simulations indicate that oxygen is the only important oxidizer of pyrite. The oxidation of ferrous to ferric iron by purely chemical means is too slow to affect the overall oxidation rate of pyrite and is not important in these systems. For the typical physical parameters used here the diffusion rate of oxygen is the primary factor controlling the rate of pyrite oxidation. The pyrite oxidation rate is decreased by decreased air-filled porosity, by increased tortuosity of the oxygen diffusion path, by increased size of the spoil fragments, and by burying the pyritic material at deeper depths. Where oxygen resupply is not limiting the results indicate that iron-oxidizing bacteria can greatly increase the rate of pyrite oxidation. Whether or not bacteria are important in these zones depends primarily on the pH of the spoil solution. In the optimal pH range, between reduced bacterial efficiency and reduced ferric iron solubility (2.0 less than or equal to pH less than or equal to 3.0), the pyrite oxidation rate is accelerated by bacterially produced ferric iron. The extent and type of chemical reactions between H/sup +/, produced by pyrite oxidation, and the spoil matrix appears to be crucial in establishing the pH of the spoil solution.
- OSTI ID:
- 6345845
- Journal Information:
- Water Resour. Res.; (United States), Vol. 20:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Atmosphere and temperature within a reclaimed coal-stripmine and a numerical simulation of acid mine drainage from stripmined lands
Effect of sewage sludge on formation of acidic ground water at a reclaimed coal mine
Related Subjects
54 ENVIRONMENTAL SCIENCES
ACID MINE DRAINAGE
MATHEMATICAL MODELS
COAL MINES
LAND RECLAMATION
PYRITE
BIODEGRADATION
OXIDATION
BACTERIA
PH VALUE
SIMULATION
SURFACE MINING
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
IRON COMPOUNDS
IRON SULFIDES
MICROORGANISMS
MINERALS
MINES
MINING
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
UNDERGROUND FACILITIES
010900* - Coal
Lignite
& Peat- Environmental Aspects
510500 - Environment
Terrestrial- Site Resource & Use Studies- (-1989)