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<br />' Wash was not lost to bedrock as a result of subsidence. The major conclusions of the study <br />' were: <br />• Recharge of the basal alluvium was from the upper sandstone facies (bedrock) and <br />not from infiltration of surface runoff. <br />' Subsidence cracks in Red Wash as the result of longwall mining were quickly filled <br />' with clay and silt preventing loss of surtace water flow to bedrock. <br />Longwall mining of panel 2 (LW-2} passed under Red Wash in September 1988. The surface <br />' elevation subsided approximately 3.7 and 4.1 feet at RW-7 and RW-9 respectively. Events in <br />Red Wash over LW-2 were expected to occur in the same fashion as those seen over LW-1. <br />' The subsidence trough was developed and any subsequent flow in Red Wash was expected to <br />form a pond. The pond would trap sediments carried in the flow(s) until full, at which time flow <br />in Red Wash would likely resume flowing in a relatively narrow active channel. <br />' The conclusions noted above were further confirmed during 1989. On July 29, 1989 a large <br />' flow event occurred in Red Wash. The subsidence trough over LW-2 filled with water. The <br />trough over LW-1 also filled, but to a lesser depth as it had filled with sediment in the past. <br />Water level measurements were taken in the monitoring holes while standing water surrounded <br />them. Readings had been taken only 18 days before. Even though the holes were surrounded <br />by standing water (approximately 3 and 4 feet deep at RW-7 and RW-9 respectively) the alluvial <br />' water depths had still decreased. <br />Although the purpose of the monitoring program was met, BME continued to monitor the Red <br />' Wash alluvial holes until water year 1996-1997. The latest monitoring results are reported in <br />Appendix F and hydrographs for each monitoring hole are presented in Appendix G of the <br />' Thirteenth Annual Hydrology Report. <br /> <br /> <br /> <br /> <br />1 <br />' ii <br />