Abstract: Rodiek, J., Verma, T.R. and Thames, J.L., 1976. Disturbed land rehabilitation in Lynx Creek Watershed. Landscape Plann., 2: 265-282. The Lynx Creek Watershed is located on the Prescott National Forest about 8 km south of Prescott, Arizona. The watershed, with an area of 7304 ha, has experienced intensive copper and gold mining activities in the past. Approximately 13% of the area still consists of patented mining claims (mainly copper). There are numerous abandoned mine shafts, waste dumps and mine tailings in the area. Past mining activities in the watershed have caused significant deterioration in water quality within and downstream from the mining sites. Mine drainage includes water flowing from mine shafts, surface runoff and seepage from mining dumps. Drainage from the numerous old mining sites contributes to the toxic mineral and sediment pollution of the water resources in the area. The pollutants in the form of dissolved, suspended or other solid mineral wastes and debris, enter in the streams of ground water. Aquatic life and recreation potential of the watershed is greatly reduced by the water pollution problem from the abandoned mines. The pollutants from the abandoned mines enter into Lynx Lake which is located 10 km southeast of Prescott. Lynx Lake, a trout fisheries lake, was created by a dam built in 1963 by the Arizona Game and Fish Department. The lake is 22 surface hectares in size with the storage capacity of 1.85 x 106 m3. The average yearly flow of sediment into the lake is 2900 m3. The sediment is slightly acidic and has a high concentration of copper, manganese, iron, zinc, and sulfates. The Sheldon dump and tailings pond are considered two major sources of pollution. Increasing need to direct additional attention toward mineral related problems made it necessary to coordinate U.S. Forest Service efforts with others involved in mining and reclamation. The Forest Service started SEAM (Surface Environment And Mining) in 1972 to coordinate interagency reclamation efforts. The Sheldon Mine dump and tailings pond were undertaken as a reclamation project through the coordinated efforts of the Forest Service, and the School of Renewable Natural Resources, University of Arizona at Tucson. The project is aimed at reclaiming some of the abandoned spoils in the Lynx Creek watershed and monitoring of water quality in the creek to evaluate the effectiveness of reclamation procedures. The reclamation approach includes recontouring, revegetating, drainage control and visual impact modification activities. The results to date have been encouraging. There was an excellent vegetation cover established within 5 weeks of seeding. Runoff and sediment control on the regraded slopes seemed quite effective. The methodology and technological experience gained from the reclamation project will provide invaluable information for reclaiming any abandoned mining sites within the Ponderosa Pine Ecosystem.

Abstract: Processes affecting neutralization of acidic coal mine drainage were evaluated within 'anoxic' limestone drains (ALDs). Influents had pH less than or equal to 3.5 and dissolved oxygen < 2 mg/l. Even though effluents were near neutral (pH > 6 and alkalinity > acidity), two of the four ALDs were failing due to clogging. Mineral-saturation indices indicated the potential for dissolution of calcite and gypsum, and precipitation of Al3+ and Fe3+ compounds. Cleavage mounts of calcite and gypsum that were suspended within the ALDs and later examined microscopically showed dissolution features despite coatings by numerous bacteria, biofilms, and Fe-Al-Si precipitates. In the drain exhibiting the greatest flow reduction, Al-hydroxysulfates had accumulated onlimestone surfaces and calcite etch points, thus causing the decline in transmissivity and dissolution. Therefore, where Al loadings are high and flow rates are low, a pre-treatment step is indicated to promote Al removal before diverting acidic mine water into alkalinity-producing materials. Published by Elsevier Science Ltd.