Feasibility of obtaining drinking water from the abandoned, flooded, underground coal mines in the area of Greenwood, Arkansas

Abandoned coal-mine water has traditionally been overlooked as a source of drinkingwater supplies, primarily because oxygenated meteoric water that floods mines reacts with pyrite and shale to produce acid drainage and high concentrations of sulfate, iron, and trace constituents. With increasing water demands worldwide, abandoned mine reservoirs are receiving additional attention as potential water supplies, and where geochemical conditions are favorable, mines serve as reliable, safe, and cost-effective water supplies.; This research, conducted in the area of Greenwood, Arkansas, in the west-central part of the state, encompasses a three-objective interdisciplinary prototype study: (1) to evaluate the resource; (2) to evaluate potential sources of problems for a municipal water supply obtained from coal mines; and (3) to passively treat the mine water to reduce operational water-treatment costs.; Characterization of the water quality from the mines in the Greenwood area involved intensive hydrologic testing, flow determination and water-quality analysis with special emphasis on processes that control rock/water interaction. The coal in this region ranges from a high-grade bituminous to a low-grade anthracite. The coal is relatively free of pyrite, and the water in the system is well-buffered. Fresh water flows into the mines from faults and from abandoned but ineffectively-plugged air vents and mine shafts. The continuous discharge from the mines has low mineral content and circumneutral pH, but water from some of the side passages is highly variable.; Development of a continuous-monitoring plan (objective 2) incorporates the science gained from objective 1 to continuously evaluate indicator parameters at different locations within the mine reservoir and along the pipeline pathway to the water plant. This task provides confidence to scientists, engineers, city officials, water-plant managers, and especially the general public, for it has safeguards installed if unexpected or undesired conditions are encountered during any aspect of use of water from this source.; Objective 3 reflects a plan for passive treatment of water from the coal mines through a constructed wetland. The benefits of this objective are multifold, including economic, educational, and political.