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Lorencito Canyon Mine Annua(Hydroiogit Monitoring Report - 2001 <br />Groundwater Quality <br />Data was collected from each of the alluvial wells (MWJC-1, MWLC-1, MWLC-2, and <br />MWPC-1) during the 1996-2000 baseline monitoring period. Alluvial wells MWLO-W and <br />MWLO-E at the loadout facility were installed during April 2002. During 2002, each of the <br />wells was monitored quarterly for water level and field parameters and water samples were <br />obtained semiannually for laboratory analyses. Summary tables showing the results from all <br />the alluvial wells are included in Appendix 1. <br />Results from the laboratory analyses were interpreted through the use of trilinear and Stiff <br />diagrams. Copies of these diagrams are also included in Appendix 1. The principal water <br />type observed in the alluvial wells is acalcium-sodium bicarbonate type. This water is <br />typically neutral with low hardness, and low to moderate salinity. The pH ranges fcom 7.42 to <br />8.7 and hardness ranges from 208 mg/L to 605 mg/L. Total dissolved solids in the samples <br />ranged from 440 to 1310 mg/L (filterable residue). Discharge associated with coalbed methane <br />has increased dissolved solids in streams and alluvial well waters. Stations MWJC-1, MWLC- <br />1, MWLC-2, and MWPC-1 show changes from the other samples taken during the period of <br />record. <br />Surface Water Quantity <br />' Watersheds in the area display dendritic drainage patterns characteristic of flow through <br />relatively flat-lying, generally uniform geologic features (Leet, et al., 1982). Eleven drainage <br />basins are within the permit boundary or received drainage from within the permit boundary. <br />' All of these drainages are included in the Purgatoire River drainage. The watersheds contain <br />both forested and open slopes. <br />Surtace Water Stations <br />Flow data was collected from each of the monitoring stations (Map 2.04.7-1) quarterly during <br />2002 (Appendix 2). Flows were determined from direct measurements of the water in the <br />stream. Analyses of flow data was performed from hydrographs generated from the flows. <br />Copies of these hydrographs are also included in Appendix 2. Analyses of the hydrographs <br />from the Lorencito Stations indicate a similarity of flow. During the first quarter, January <br />through March, flows were low or non-existent at some stations. During the higher <br />precipitation second quarter, flows were higher especially during May when runoff was high. <br />Flows at the side canyon stations were extremely low with some stations exhibiting no flow <br />conditions over several months. <br />AHR-00.4"!5\March 10, 2007 C <br />