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WALDEN COAL COMPANY Annual Hydrologic Report October 1, 1985 - September 30, 1986 Surface Water Walden Coal Company collected surface water samples when the sedimentation ponds discharged and when Mann Draw flowed, as required by Colorado Department of Health (CDOH) N. P.D.E. S. permit number CO-00 36854, Jackson County and Colorado Mined Land Reclamation Permit number CO-81-021. Copies of the discharge/flow schedule and the results of the samples are attached. Total suspend solids and iron levels decreased significantly between the upstream and downstream samples taken in [dann Draw. All effluent limitations were met throughout the year. C pond did not discharge because water designed to flow into C pond was redirected into the pit. Water from the pit was used for dust control or was pumped into one of the other three sedimentation ponds as necessary. CDOH requested that six (6) pit water samples be taken to determine if effluent limitations on Walden's NPDES permit needed to be altered. The results of those samples (attached) were forwarded to CDOH and no changes have been made to the effluent limitations. Ground Water Ground water depth was monitored at eleven approximately 25 foot deep monitoring wells in Mann Draw on a monthly basis (see attached). Most of the wells remained dry or near dry throughout the year. Quarterly water quality samples were collected from well 30C, the only well with enough water to sample. Results are attached and do not show any significant variability from past results. No sample was collected in December, 1985 due to insufficient water in the designated monitoring wells. A maximum of approximately 9,000 gallons of ground water flowed into the pit on a daily basis. Summary Water quality and quantity at the Bourg 67ine has not changed to any noticable extent as a result of the mining operation.