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iii iiiiiiiiuiiiiii <br />999 <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmem of Natural Resources <br />1111 Sherman 5c, Room 215 <br />Denver, l nlnrado NO?Ul <br />Phone 1 i0 p RbGJ 5L7 <br />FAY: 1 4f13) K3'_ ii 106 <br />October 17, 1996 <br />Mr. Brian D. Gontarek <br />Environmental Engineer <br />The Pittsburg & Midway Coal Mining Company <br />P.O. Box 6518 <br />Englewood, Colorado 80155-6518 <br />RE: Edna Strip Mine (C-80-001) <br />1995 Annual Hydrology Report <br />Dear Mr. Gontarek: <br />I~~~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />Roy Rnnrca <br />Governor <br />lames 5. Lochhrdd <br />&rr wi.~e Direanr <br />Michael tl. Long <br />Division Dnecloi <br />The Division has completed a review of the 1995 Annual Hydrology Report for the Edna Mine. <br />Our review indicates all required monitoring was conducted, and results are consistent with <br />predictions of the probable hydrologic consequences (PHC) made in the approved permit <br />application package. <br />The PHC section of the permit application package.notes that high concentrations of sulfate <br />would be expected at surface water monitortng site TR-D in late spring. Monitoring data for <br />1995 supports this prediction since sulfate reached a high of 490 mg/I in April. The predicted <br />highest annual avera a for sulfate at TR-D is 392 mg/I. Monitoring data for 1995 indicates an <br />average of 232.2 mg~l, which is below the predicted maximum. <br />The PHC also predicts a maximum Total Dissolved Solids (TDS) concentration at TR-D of 1190 <br />mg/I. The 1995 high at TR-D was 810 mg/l. The predicted annual average for TDS is 605 <br />mg/I. The 1995 average was 373.75 mg/1, also below the predicted maximum. <br />The report discusses elevated TDS levels at well TR-1.5, offering possible explanations for the <br />reason for the increase (beaver dam inundating the area near the well and disturbance of <br />alluvium unrelated to mine activities). Both explanations indicate that if these reasons are valid, <br />TDS levels should return to the historic normal range in future monitoring periods. The <br />Division accepts that these may be valid explanations, and will review future monitoring data <br />to determine whether or not TDS levels do in fact return to the normal range. <br />We appreciate that the report was well organized and presents data in a format such that trends <br />were easily recognized and comparisons to the PHC could be readily made. If you have any <br />questions or need additional information, please contact me. <br />Sincerely, <br />~'~~~c~.,~ZU1,~'yl'v~~'t <br />Susan L Burgmaler <br />Environmental Protection Specialist <br />c: Larry Routten <br />sLa~JOi~rn <br />