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Lorencito Canyon Mine Annual Hydrologic MoniforinR Re0ort - 200] <br />on the Purgatoire River, likely due to higher TDS discharges from coalbed methane activities <br />in Lorencito Canyon. <br />' Spring and Seep Stations <br />No water quality samples were collected at springs during 2002, however, water quality <br />sampling during the baseline period revealed slightly to moderately alkaline, slightly hard, <br />calcium-sodium bicarbonate water, with total dissolved solids ranging from 300 mg/L to 710 <br />' mg/L. Total alkalinity in the samples ranged from 223 mg/L to 409 mg/L, and hardness ranged <br />(as CaCO3) from 214 mg1L to 388 mglL. pH ranged from 6.70 to 9.15. A summary of the <br />monitoring results are contained in Appendix 3. <br />Pond Sites <br />One pond site was monitored during 2002 (PJC-1). This pond was dry during the May sampling <br />event. Historic monitoring indicated pond sites varied with pH ranging from 7.5 to 8.1 and <br />conductances ranging from 190 µmhos to 275 µmhos. Water levels vazied from site to site, <br />however, no flow was observed at any of the sites. <br />Sediment control ponds have been constructed to treat disturbed area runoff. Two discharges <br />from Pond 9 were recorded on September 10 and 19, 2002 (Appendix 3). The discharges met <br />water quality standards established in the NPDES permit. <br />Conclusions <br />Coal mining operations began at Lorencito during the fourth quarter of 2001 and were <br />temporarily ceased in July 2002. Monitoring to date does not indicate any impacts to local or <br />regional water resources from mining, however, changes in water quality over the past two years <br />may be caused by increased coalbed methane development in lower Lorencito Canyon and side <br />canyon tributaries. <br />AHR-00.0]J\March 10, 20W <br />