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STATE OF COLORADO <br />DIVf510N Of MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 D I V i 5 1 o N O F <br />Phone: (303) 866-3567 lVt 1 Pl E RA L S <br />FAX: (303) 832-8106 & <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />Bill Owens <br />Governor <br />Greg E. Walther <br />March 21, 2003 Executive Director <br />Ronald W. Cattany <br />Division Director <br />Jerry Koblitz <br />Principal <br />Greystone Development Consultants <br />5231 South Quebec Street <br />Greenwood Village, CO 80111 <br />RE: 2002 Annual Hydrology Report Review, Lorencito Canyon Mine, #C-96-084 <br />Mr. Koblitz: <br />The Division of Minerals and Geology has completed review of the 2002 Annual Hydrology <br />Report (AHR) for the Lorencito Canyon mine. After initial approval in 1997, the mine delayed <br />start-up of operations until October 2001. The mine was active during 2002 from January until <br />July, at which time production was halted temporarily due to market conditions. <br />Monitorinl? Frequency <br />The operator met the approved monitoring frequency in 2002. Alluvial wells and surface sites <br />were visited and sampled for water level or flow and field parameters on a quarterly basis during <br />active operations as required. Samples were taken for laboratory analysis during the second and <br />fourth quarters as required. Water samples were analyzed for the approved analytical list as <br />required. One spring is monitored but was found dry due to the drought conditions during 2002. <br />Water puantity and Quality <br />March 2001 data, as reported in the 2000 Annual Hydrology Report, is the most representative pre-mine <br />data for the stations currently part of the approved hydrologic monitoring program. <br />Water quantity was not affected by mining activities. Minimal water was retained in sediment <br />ponds due to drought conditions. Dischazge from the disturbed area was nearly non-existent. <br />Coal bed methane (CBM) development and concurrent water dischazge influences the surface <br />and ground water systems. Water quality does not appeaz to be impacted by mining activities. A <br />slight increase in total dissolved solids (TDS) is noted on the Purgatoire River below the <br />confluence with Lorencito Canyon (170 mg/] upstream; 220 mg/1 downstream). This increase is <br />