Charles A Cravotta, III, PhD, PG (Former Employee)
Science and Products
Filter Total Items: 89
Water-quality data for two surface coal mines reclaimed with alkaline waste or urban sewage sludge, Clarion County, Pennsylvania, May 1983 through November 1989
Water-quality and other hydrologic data for two surface coal mines in Clarion County, Pa., were collected during 1983-89 as part of studies conducted by the U.S. Geological Survey in cooperation with the Pennsylvania Department of Environmental Resources. Water samples were collected from streams, seeps, monitor wells, and lysimeters on a monthly basis to evaluate changes in water quality resultin
Authors
D.L. Dugas, C.A. Cravotta, D. A. Saad
Acid base accounting--An improved method of interpreting overburden chemistry to predict the quality of coal-mine drainage
Acidic mine drainage (AMD), which results from the accelerated oxidation of pyrite (FeS2 ) in mined coal and overburden, has contaminated thousands of miles of streams in the Appalachian region of the United States. Acid‐base accounting (ABA), which simplifies the complex hydrogeochemical system through use of a limited number of variables, commonly is used to predict the post‐mining occurrence of
Authors
Keith Brady, Charles A. Cravotta
Geochemical evolution of acidic ground water at a reclaimed surface coal mine in western Pennsylvania
Concentrations of dissolved sulfate and acidity in ground water increase downflow in mine spoil and underlying bedrock at a reclaimed surface coal mine in the bituminous field of western Pennsylvania. Elevated dissolved sulfate and negligible oxygen in ground water from bedrock about 100 feet below the water table suggest that pyritic sulfur is oxidized below the water table, in a system closed to
Authors
Charles A. Cravotta
Effectiveness of the addition of alkaline materials at surface coal mines in preventing or abating acid mine drainage--Part 1. Geochemical considerations
The addition of alkaline materials to supplement deficient "neutralization potential" (NP) of mine spoil, and thus to prevent or abate acid mine drainage, has riot been successful at most surface coal mines in Pennsylvania. A basic problem may have been improper accounting for acid‐production potential and thus inadequate addition rates of calcium carbonate (CaCO3 ), calcium oxide (CaO) , or calci
Authors
Charles A. Cravotta, Keith Brady, Michael W. Smith, Richard L. Beam
Effectiveness of the addition of alkaline materials at surface coal mines in preventing or abating acid mine drainage--Part 2. Mine site case studies
The effectiveness of preventing or ameliorating acid mine drainage (AMD) through the application of alkaline additives is evaluated for eight surface coal mines in Pennsylvania. Many of the mine sites had overburden characteristics that made prediction of post‐mining water quality uncertain. Alkaline materials were applied at rates ranging from 42 to greater than 1,000 tons as calcium carbonate pe
Authors
Keith Brady, Michael W. Smith, Richard L. Beam, Charles A. Cravotta
Science and Products
Filter Total Items: 89
Water-quality data for two surface coal mines reclaimed with alkaline waste or urban sewage sludge, Clarion County, Pennsylvania, May 1983 through November 1989
Water-quality and other hydrologic data for two surface coal mines in Clarion County, Pa., were collected during 1983-89 as part of studies conducted by the U.S. Geological Survey in cooperation with the Pennsylvania Department of Environmental Resources. Water samples were collected from streams, seeps, monitor wells, and lysimeters on a monthly basis to evaluate changes in water quality resultin
Authors
D.L. Dugas, C.A. Cravotta, D. A. Saad
Acid base accounting--An improved method of interpreting overburden chemistry to predict the quality of coal-mine drainage
Acidic mine drainage (AMD), which results from the accelerated oxidation of pyrite (FeS2 ) in mined coal and overburden, has contaminated thousands of miles of streams in the Appalachian region of the United States. Acid‐base accounting (ABA), which simplifies the complex hydrogeochemical system through use of a limited number of variables, commonly is used to predict the post‐mining occurrence of
Authors
Keith Brady, Charles A. Cravotta
Geochemical evolution of acidic ground water at a reclaimed surface coal mine in western Pennsylvania
Concentrations of dissolved sulfate and acidity in ground water increase downflow in mine spoil and underlying bedrock at a reclaimed surface coal mine in the bituminous field of western Pennsylvania. Elevated dissolved sulfate and negligible oxygen in ground water from bedrock about 100 feet below the water table suggest that pyritic sulfur is oxidized below the water table, in a system closed to
Authors
Charles A. Cravotta
Effectiveness of the addition of alkaline materials at surface coal mines in preventing or abating acid mine drainage--Part 1. Geochemical considerations
The addition of alkaline materials to supplement deficient "neutralization potential" (NP) of mine spoil, and thus to prevent or abate acid mine drainage, has riot been successful at most surface coal mines in Pennsylvania. A basic problem may have been improper accounting for acid‐production potential and thus inadequate addition rates of calcium carbonate (CaCO3 ), calcium oxide (CaO) , or calci
Authors
Charles A. Cravotta, Keith Brady, Michael W. Smith, Richard L. Beam
Effectiveness of the addition of alkaline materials at surface coal mines in preventing or abating acid mine drainage--Part 2. Mine site case studies
The effectiveness of preventing or ameliorating acid mine drainage (AMD) through the application of alkaline additives is evaluated for eight surface coal mines in Pennsylvania. Many of the mine sites had overburden characteristics that made prediction of post‐mining water quality uncertain. Alkaline materials were applied at rates ranging from 42 to greater than 1,000 tons as calcium carbonate pe
Authors
Keith Brady, Michael W. Smith, Richard L. Beam, Charles A. Cravotta
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