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1 <br />2.1 Assessment of Groundwater <br />There are essentially two ways in which mining activi- <br />' ties at Mt. Gunnison could affect groundwater. First, <br />extension of mine entries and mining of the coal could <br />cause water to move from formations above the coal seam <br />into the mine. Of particular concern is the role of <br />possible roof collapse and mine subsidence on water- <br />' bearing formations above the coal. Second is the pos- <br />sible impact of waste material disposal on groundwater <br />' quality. <br />Although the permeability of the F Seam and overlying <br />' strata is very low and the quantity of water stored in <br />these units is also low, water from these strata will <br />' occasionally seep into the mine. <br />' The entries produced drips during snowmeTt runoff. <br />Inflows were considerably less than 3 gpm and were not <br />sustained. The only location where sustained flows in <br />excess of 3 gpm were encountered was at the Sylvester <br />' Gulch Return Area. The measurements of inflows are <br />' provided in Table I.4-1. Corresponding location where <br />inf]ow was encountered is shown on Exhibit III. <br />The seasonal pattern of mine inflows observed near the <br />' Sylvester Gulch Return and the mine entries indicate <br />that the colluvium, coal and bedrock are recharged <br />-17- <br />