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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 832-8106 <br />February 3, 2003 <br />DIVISION OF <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />Bill Owens <br />Governor <br />Jerry Koblitz Greg E. Walther <br />Principal Executive Director <br />Gre stone Develo ment Consultants Ronald W. Cattany <br />Y P Acting Division Director <br />5231 South Quebec Street <br />Greenwood Village, CO 80111 <br />RE: 2000 and 2001 Annual Hydrology Report Review, Lorencito Canyon Mine, #C- <br />96-084 <br />Mr. Koblitz: <br />The Division of Minerals and Geology has completed review of the 2000 and 2001 <br />Annual Hydrology Reports for the Lorencito Canyon mine. After initial approval in 1997, <br />the mine delayed start-up of operations until October 2001. <br />The original hydrologic monitoring plan was designed for a combination of surface and <br />underground mining over a significant portion of the 17,000 acre permit area. <br />Monitoring commenced under this original plan and continued until the operator <br />requested a reduction in frequency of monitoring approved in early 1999. <br />Subsequently, as a result of a modified mine plan as part of PR-01, the mine proposed <br />a more limited hydrologic monitoring plan based on this more conservative mine plan <br />the focused exclusively on surface mining activities in the Jeff Canyon area. <br />Ground water pumping due to coal bed methane production and subsequent discharge <br />of this water to the surface water system has altered both the surface and underground <br />hydrologic regime since initial baseline data collection in 1996. No mining activities <br />occurred until October 2001. This alteration in the hydrologic system continued until the <br />modified mine plan under PR-01 was reviewed and approved. Therefore, March 2001 <br />data, as reported in the 2000 Annual Hydrology Report, is the most representative pre- <br />mine data for the stations currently part of the approved hydrologic monitoring program. <br />Other monitoring stations remain as originally approved but are not currently part of the <br />approved monitoring program. The baseline data collected over the period 1996-2001 <br />is suspect with regard to its representation of pre-mine conditions regarding coal mining <br />activities. <br />