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-24- 1) When underground mine workings encounter saturated portions of the coal seams, water will accumulate requiring water to be pumped from the mine. The removal of this water will lower piezometric surfaces in the coal seams and immediately adjacent strata. The distance from the mine that this impact will extend is dependent upon the transmissivity and storage coefficient properties of the strata. In most coal-bearing strata, these properties are such that the impact rarely extends more than a mile from the edge of the mine workings. The two mines where this phenomena will occur are the Twin Pines No. 2 Mine and the Dorchester No. 1 Mine. As was previously discussed in the probable hydrologic consequences section of this document, the Caldirola Mine well is within one mile of the proposed Twin Pines No. 2 Mine. Although, the piezometric surface may be lowered in the western portion of the abandoned Caldirola Mine, the piezometric surface in the eastern portion of the mine will not be affected. Thus, the quantity of water available for emergency purposes for the town of Coal Creek from the eastern portion of the mine will not be affected. In the Dorchester No. 1 i4ine permit application currently under review by the Division, two wells are described that could be impacted by the lowering of the piezometric surface. Monitoring wells will be constructed between the ~ mining activities and the two wells to detect changes in the piezometric ~ surface. This monitoring should be sufficient to minimize impacts to these wells. 2) No subsidence-induced inflows are predicted for the Twin Pines No. 2 Mine nor the Newlin Creek Mine. However, subsidence-induced inflows are anticipated at the Dorchester No. 1 Mine, resulting from mining beneath Newlin Creek, a perennial stream. Because this water feature is within the subsidence zone, the Division, during its review of the Dorchester permit, is emphasizing control and prediction of subsidence. The significance of subsidence of this drainage is limited because the entire flow of the stream is diverted into the Florence City pipeline upstream of the mining operation. Therefore, prediction of the impact to the prevailing hydrologic balance hinges on the functioning of the Florence pipeline. The Division assumes, for the purposes of this report, that the cumulative hydrologic impact of subsidence-induced inflows will be negligible. 3) The only mines that may affect the quality of ground water in the general area are the Twin Pines No. 2 t4ine and the Dorchester No. 1 Mine. Potential impacts to ground water quality by those operations are considered negligible as discussed below.