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<br />2.0 WATER LEVELS <br />Water levels have been measured in 28 wells at the Trapper Mine. <br />Wells GF1, GF3, and GD2 are flowing wells and have not been routinely <br />measured for static water head. A few recent water levels have been <br />measured on well GC2. Well GD1 is not measureed for water level <br />because a pump is installed in this well and well GZ1 is dry. <br />The location of the monitoring wells is shown on Map No. 2-1. <br />Wells GD1, GF1, and GZ1 are completed in the Twenty Mile Sandstone, <br />while wells GF2 and GZ2 are completed below the' R coal in the U <br />aquifer system. Five wells, GA1, GE1, GZ3, GD2, aiad GF6, are used to <br />monitor the QR aquifer. Wells GA2, GB1, and GF3 are used to monitor <br />the RLM aquifer. Four wells, GBS, GC1, GE2, and GF4, are used to <br />observe changes in the HI aquifer. Wells GB2, GC2, GBB1, and P8 are <br />used to monitor the Third White Sandstone aquifer. Wells GE3, GBB2, <br />and P5 are completed in the Second White Sandstone between the G and F <br />coals while well P3 is perforated in the Lewis Shs~le. Four alluvial <br />wells, GBB3, GC3, P1, and COY are also monitored. <br />2.1 WATER-LEVEL CHANGES <br />• The water-level changes for the period of record are presented on <br />figures in Appendix A. Depth to water and water level elevation are <br />tabulated in this appendix, also. Table A-1 presents the water level <br />data for wells GA1, GA2, GB1, and GB2. Water-level changes for well <br />GA1, which is completed in the QR aquifer, are shown on the hydrograph <br />on Figure A-1 of Appendix A. The Q and R coal seams are presently <br />being mined approximately 2000 feet from this well which is the <br />closest mining of the Q and R has been to well GA1. Water levels were <br />fairly steady during the first couple of years of monitoring and then <br />gradually declined from late 1976 through 1982. Water levels have <br />risen at approximately ten feet per year since early 1983 and levels <br />are presently above the pre-mine levels. Increase in recharge to the <br />QR aquifer is the most likely reason for the rise in water level in <br />the last few years. Another possible explanation i.s the migration of <br />ground water after blasting from the top of the hill to the base of a <br />particular cut. This could cause water levels in <rn aquifer near the <br />base of these cuts to rise from the influx of additional ground water. <br />The decline in water levels in 1977 through 1982 could be due to mine <br />dewatering or a reduction in natural recharge or a combination of <br />these factors. <br />Water levels for well GA2 (see Figure A-2), which is completed in <br />the KLM aquifer, have responded similarly in the last three years with <br />a large water- level rise, but water levels in this aquifer had not <br />dropped nearly as much prior to the rise. <br />2-1 <br />