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<br />III IIIIIIIIIIIII III <br />999 .... _ ... _. ...._ ~.-......._...L. .. <br /> <br /> <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman $t., Room 215 ~ <br /> <br />Denver, Colorado 80'_03 DIVISION O F <br />Phone: 1303) 866-7557 MINERAL $ <br />FAR: 13031 8328106 bt <br /> GEOLOGY <br /> RECLAMATION <br /> MINING•SAFETY <br />February 28, 2000 <br /> BiII Owens <br /> <br />Michael G. Altavilla Governor <br /> Greg E. Walther <br />Seneca Coal Company Eaecolrve Drteclor <br />P.O. Box 670 Michael B. long <br /> <br />Hayden, CO 81639 Division Director <br />Re: Yoast Mine (Permit No. C-94-082) <br />1999 Annual Hydrology Report Review <br />Deaz Mr. Altavilla: <br />The Division has reviewed Seneca Coal Company's (BCC's) 1999 Annual Hydrology Report <br />(AHR) for the Yoast Mine. The frequency of data collection is in compliance with the approved <br />monitoring plan contained in the permit document. SCC did an excellent job at collecting the <br />required monitoring data. The report is well written and the data are presented in a concise <br />manner. The Division notes that a few samples could not be obtained due to dry or low flow <br />conditions. Well YWCU31 was dry at all three attempts to obtain water level information. <br />Surface water site YSSF2 was dry during the baseflow period and the third triannual water <br />quality sample could not be obtained. Water quality samples for laboratory analysis were not <br />obtained for springs YSPG6 and YSPG10 due to low flow conditions (less than 5 gallons per <br />minute). <br />SCC adequately addressed the Division's comments on the 1998 AHR by incorporating <br />responses into the 1999 AHR. The Division has the following comment regarding the 1999 <br />AHR. <br />On page 7 of the 1999 AHR, SCC addressed the Division's request to identify the potential <br />source for the apparent elevated levels of certain metals and sulfate in groundwater. The <br />Division notes that in the 1999 AHR, SCC indicates that elevated levels of iron, manganese, and <br />sulfate were present in samples from specific monitoring wells prior to mining. The Division <br />concurs with BCC's findings regazding the baseline levels of these constituents prior to mining. <br />Groundwater samples from these same monitoring wells continue to exceed the groundwater <br />agricultural use standards for iron, manganese, and sulfate as reported for Water Year 1999. <br />Please continue to address these exceedances in future AHRs so that any significant trends can be <br />identified and conclusions regazding PHC predictions can be verified. <br />