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SNOWCAP COAL COMPANY, INC. <br />HYDROLOGIC ANALYSIS OF JERRY CREEK <br />SURFACE WATER GAUGING STATION <br />(SWGS -08) <br />The following analysis and attachment are based on Snowcap Coal Company's Mining <br />and Reclamation Permit #C- 1981 -041 and monitoring data from Snowcap's Annual <br />Hydrology Reports. This data represents the surface water gauging station reported as <br />SWGS -08 and located in Jerry Creek, an intermittent drainage which drains generally <br />southeastward in a deeply incised canyon to the Colorado River. <br />Monitoring of Jerry Creek at SWGS -08 was started in 1995 and at the time was included <br />in Snowcap's mine permit boundary. The intermittent flow is measured at the culvert <br />near the Highline Canal. Monitoring from 1995 to June 1999 was once a month for <br />instantaneous flow and for peak flow since the last time it had been monitored. The peak <br />flow was estimated from the flow marks, as well as chalk marks, in the culvert. Beginning <br />July 1999 instantaneous flow has been monitored monthly and peak flow was <br />discontinued. The diagram represents the monitored flow in Jerry Creek. <br />During the life of the mine, the operator mined coal using room - and - pillar methods. ' The <br />mining plan provided for leaving protective pillars beneath the creek to eliminate the <br />possibility of subsidence. A 12° angle -of -draw was used to calculate protection zones <br />under the creek. Detailed information regarding pillar design for subsidence control can <br />be found in Tab 20 of Snowcap's permit. <br />It has been over twelve years since any mining has been conducted under Jerry Creek. <br />All the underground mined areas and the surface acres containing Jerry Creek were <br />released from Snowcap's permit with the approval of SL -7 in February 2008. Since all <br />acreages and disturbances associated with this monitoring have been released and the <br />intermittent flow of Jerry Creek has not been adversely impacted by mining activities, <br />monitoring has been suspended at SWGS -08. <br />NOTE: This analysis not intended for inclusion into Snowcap Coal Company's mining permit. <br />TR -62 07/11 <br />