Acid Mine Drainage Control Utilizing Fly Ash

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by Kevin L. Harshberger, West Virginia Univ, Morgantown, United States,
John J. Bowders, Jr., West Virginia Univ, Morgantown, United States,

Document Type: Proceeding Paper

Part of: Energy in the 90's:

Abstract: Acid mine drainage is a serious environmental problem confronting the Appalachian region. Fly ash, the air particulate residual from the combustion of coal, is also an environmental concern in that more than 50 million tons of fly ash are produced each year. Utilizing fly ash to control acid mine drainage may be an economical method of reducing the extent of both problems. Fly ash could be used to create low permeability caps or divert groundwater around acidic materials at newly reclaimed surface mines or mines that have been unsuccessfully reclaimed. The project reported herein involves the development of low permeability grouts for injection into acidic spoil materials. The primary grout constituent is a coal combustion fly ash. Admixtures including clays, fluidized bed ash, scrubber sludge, lime and spent lime have been utilized. The permeability of the ash was found to be 6E-04 cm/s. Scrubber sludge as an admixture lowered the permeability to 1E-06 cm/s. All admixtures, with the exceptor of fluidized bed ash, lowered the permeability of the grout. Large scale laboratory acidic spoil piles have been constructed. Pre-grouting water quality analysis showed pH's around 2.7, and concentrations of Fe, Mn, and Al at roughly 2,000 mg/l, 10 mg/l, and 150 mg/l respectively. Flow rates in the spoil approached 0.14 l/s. Grouting of the spoil is to begin presently. Post-grouting flowrates and water qualities will be analyzed and compared to pre-grouting data to assess the grout effectiveness. Field sites with AMD problems in northeastern WV and southwestern PA are also currently being investigated for fly ash demonstration applications.

Subject Headings: Grouting | Fly ash | Mines and mining | Acids | Drainage | Recycling | Water quality | Water pollution | Permeability (material) | Pennsylvania | North America | United States | West Virginia

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