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This water is discharged to the nearest settling reservoir or is used for dust suppression. The Division of <br />i <br />Water Resources has approved Trapper's request to change the status of the GD-1 well to backup <br />status. The well permit number for GD-1(2) is 019872-F. The approved backup well permit number is <br />041203F. <br />Groundwater use near Trapper Mine has been presented in Section 2.7.5.4. The potential use of <br />groundwater from aquifers in and near Trapper Mine is mainly livestock and wildlife watering and fisheries <br />development. Most of the groundwater quality is not acceptable for drinking purposes and the quantity <br />of supply is not sufficient for irrigation. <br />Trapper Mine wells for which Trapper holds the water rights will be transferred to the surface owner in <br />accordance with Colorado water law, if both Trapper Mining Inc. and the surface owner desire the <br />transfer, and the Division of Mined Land Reclamation approves the transfer. <br />4.8.2.2 Groundwater Inflow to the Mine <br />Studies have shown that the coal and associated Sandstones in the Trapper Mine are saturated at some <br />sites (Woodward-Thorfinnson, 1975, and Golder, 1976). Pump tests were carried out to determine <br />transmissivities of these units and to estimate the amount of water that would flow into the initial mine <br />boxcuts. Woodward-Thorfinnson (1975) estimated a flow rate of up to 175 gpm per 1000 feet of boxcut. <br />Pump tests by Golder (1976) also indicated significant transmissivities in the coal and sandstones. <br />Limited continuous pumpage of water has been initiated by the Trapper mining activities. The specific <br />yield of the aquifers which the mine penetrates probably is in the range of 0.01. This very small specific <br />yield limits the amount of available water in these aquifers. The blasting ahead of mining probably <br />increases the permeability of the formations significantly. A large increase in permeability with the large <br />gradients in the aquifers would enable most of the aquifer to be drained before mining. Mine inflow from <br />groundwater is therefore not expected to be of significantly higher quantity in the future in the southern <br />pits (see annual reports for pit pumping rates). Mining at the north end (Ashmore Pit) of the mine has the <br />most potential to encounter the largest volume of water. <br /> <br />4-224 <br />