The objective of this work, conducted by West Virginia University under Cooperative Agreement DE-FC26-03NT41908, was to identify cost saving alternatives to the current coal- fired power plant cooling process using non-traditional water sources such as coal mine discharges. In particular, deep mine discharges have the potential to improve the efficiency of the cooling process due to the cool (~ 50°F), constant water temperatures while at the same time reducing the capital cost of acquiring the cooling water. In addition, the potential use of the underground mines themselves as a wide area heat sink was evaluated for its feasibility. The underground mines for this study were in the Pittsburgh coal basin, which underlies northern West Virginia and southern Pennsylvania.

The work was conducted in two parallel tracks referred to as scenario A and scenario B.

Under scenario A, a conceptual engineering design was applied to the knowledge of mine hydrology to identify mine water reservoirs of sufficient water flow to provide cooling water for a 600 MW coal-fired power plant. The costs and feasibility of obtaining, treating and utilizing this water were compared to the costs and feasibility of obtaining sufficient water from a surface water source. Results of the scenario A evaluation were as follows:

1. Eight sites were identified in the Pittsburgh Coal Basin where conditions may be suitable for application of this technology. Upon further examination, four sites have been identified where sufficient mine water is available for power plant cooling.
2. Current laws and regulations do not contemplate the use of mine water for power plant cooling. Uncertainties remain with regard to long-term liability for the mine water discharge, and appropriation of the mine water for the power plant's use.
3. The use of mine water for power plant cooling appears to be economically viable for net alkaline mine water.
4. The use of hydrogen peroxide has the potential to reduce capital and operating costs in AMD treatment.
5. Although, anecdotal information suggests that mine pumping does not induce AMD formation or mine subsidence, additional research is needed before mine dewatering projects are conducted.
6. Non-monetary factors may influence the use of mine water for power plant cooling.

Under scenario B, the ability of abandoned coal mines to serve as a heat sink – extracting cool water from a mine and re-injecting warm water into the same mine or an adjacent mine – was investigated. Findings for scenario B were as follows:

1. One site was identified where such cooling is technically feasible and attractive in terms of capital costs.
2. Flow and thermal modeling is required to establish design parameters for this type of cooling. Thermal modeling establishes the area of the mine needed to achieve the required cooling, while flow modeling produces average mine residence times that must be known to assure cooling performance.
3. The first scenario involved injecting hot water from the power plant into the Vesta mine, and extracting the cooled water from the Clyde mine. The median travel time was approximately 206 days and the capital cost is 75% of the base case with operating costs that are 119% of the base case.
4. A second scenario involved injecting hot water from the power plant into the Vesta mine, extracting the cooled water from the Clyde mine, reinjecting the cooled water into the Marianna 58 mine and extracting the cooler water from the upper part of Marianna 58. This scenario has capital costs that are 80% of the base case with operating costs that are 193% of the base case.