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,A DIVISION OF MINERALS AND GEOLOGY Department of Natural Resources 7313 Sherman St., Room 215 Denver, Colorado 80203 Phone: (303) 8663567 FAX: (303) 832-8106 September 23, 2005 Dennis Tones Seneca Coal Company P.O. Box 670 Hayden, CO 81639 Re: Seneca II-W Mine (Permit No. C-82-057) 2004 Annual Hydrology Report Review Deaz Mr. Jones: COLORADO DIVISION OF MINERALS GEOLOGY 0.ECLAMATION•MIN ING SAFETY•SCIENCE Bill Owens Governor Russell George Executive DIreLYGr Ronald W. Cattany Division Director Natural Resource Trustee The Division has reviewed Seneca Coal Company s (SCC s) 2004 Annual Hydrology Report (AHR) for the Seneca II-W Mine. The AHR was received on Febniary 25, 2005 and contains water quality and quantity data for the 2004 Water Yeaz. The 2004 report was filed in a timely manner, and the report was thorough and comprehensive. Water monitoring was conducted in compliance with permit specified schedules at approved sites, and the report includes appropriate data presentation and evaluation of observed compliance with relevant standards and PHC projections. The report narrative was properly updated this yeaz to reflect PHC projections as revised by Permit Revision No. 3. Replacement wells for the failed series of wells (W-25) below Pond 016A and for wells that were otherwise abandoned (GW-4 Series), were drilled in September 2004. Ground water data for the replacement wells was not included in the 2004 report, but should be included in the 2005 Water Yeaz AHR. The new wells were incorporated into the permit, with the required completion information, in 2005. Two attempts have been made to permanently seal the failed wells below Pond 016A. Both attempts have been unsuccessful. SCC is working with the Division and the State Engineers Office to further develop plans for proper abandonment of these wells. There were no excursions of NPDES effluent limits during the 2004 Water Yeaz. SCC indicates in the Ground Water Oualit_y Summary on page 13 of the AHR that all aquifers prior to mining at the Seneca II-W Mine have exhibited several pazameter concentrations in excess of both irrigation and livestock standazds compared, rendering them questionable regazding their suitability for either irrigation or livestock. SCC further indicates that the low transmissivities of all bedrock aquifers affected by mining would also preclude their use for yielding sufficient water for irrigation, or even livestock. There is no mention of ground water use for drinking water, other than the fact that bottled water is consumed at the mine site as opposed to water from the shop well. STATE OF COLORADO