Date of Graduation


Document Type



Two aspects of acid mine drainage (AMD) production were studied on a laboratory scale: the role of leaching, and the effectiveness of phosphate amelioration. The leaching study was based on an assumption of an earlier oxidation/leaching field model: that oxidation is independent of leaching. A SAS program was written which can simultaneously fit all three parameters of this field model. The model was generalized to include the effect of initial sulfate sulfur. A deterministic oxidation/leaching model was developed and applied to two continuous, unsaturated flow trickle bed reactors. First-order leaching rate constants were calculated to be 0.0888 days{dollar}\\sp{lcub}-1{rcub}{dollar} for refuse particles ranging in diameter from 1/4 to 5/8 inches, and 0.0703 days{dollar}\\sp{lcub}-1{rcub}{dollar} for 1/8 to 4 inch particles. A semi-static leaching study was conducted on four scales (0.1 L to 100 L). Oxidation and leaching rates were dependent on particle size. Oxidation rates were also strongly temperature dependent. Three sources of phosphate from North Carolina were tested as ameliorants on two West Virginia coal mine refuse types using a Soxhlet extraction weathering procedure. Only a semi-refined phosphate was an effective ameliorant, and no ameliorant was economically feasible. Phosphate amelioration reduced leachate acidity, but did not reduce sulfate production. SEM and porosimetry studies intended to divulge the mechanism of amelioration were inconclusive.