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_ ~~ ~5 III IIIIIIIIIIIIIIII STATE OF COLORADO Roy Romer, Governor Patricia A. Nolan, MD, MPH, Executive Director Dedicated to protecting and improving the health and environment o! the people orColorado 4300 Cherry Creek Dr. s. Laboramry Building Denver, Colorado 80222-1530 4210 E. 11th Avenue Phone (3031 692-2000 Denver, Colorado 802 2 0-7 71 6 U07) 691-4700 September 30, 1994 Murari P. Shrestha Assistant Manager of Engineering Western Fuels-Utah, Inc. 405 Urban St., Suite 305 Lakewood, CO 80228 RE: Response to Comments Western Fuels-CO, LLC CDPS No. CO-0000213 Montrose County Dear Mr. Shres[ha: New Horizon Mine •.~ 0~ ~~ Colorado Deparnnent oFPubGc Htstlth and Envitonmatt OCTp4 Qivision of muierals a Geology We have reviewed the topics covered by your comments in response to our September 9, 1994, letter. As 1 understand it, your primary concerns are: WET requirements for outfalls 001 and 007 and the monitoring frequencies for these two outfalls. The receiving water low flows were a related concern. I asked our Standards Unit to reassess the low flows for Tuttle Draw and Calamity Draw. They reviewed and responded that the Division files show that these draws are periodically dry. As 1 mentioned in my September 9th letter, we utilize a 10-year minimum data base for calculating low flows. If the stream was dry at any time during the review period, this usually results in the low Oows being designated as zero. On this basis, the low flows must remain at zero. This Only affects the WET IWC in this permit, which will remain at 100°h. We have reviewed all the WET results for outfall 001 that you submitted. We cannot totally eliminate WET requirements for this outfall. These results show that this discharge has contributed very little toxicity during the test periods, however because of the large spoils spring contribution to this outfall the potential for toxicity remains. The monitoring records show that this source results in a significantly high continuous flow from this outfall -from 80,000 to 670,000 gpd 30 day average discharge flow during the period reviewed during permit renewal--This makes this discharge quite different from a surface runoff discharge that only occurs for short periods in response to precipitation events, we note that the other five surface runoff-only outfalls did not discharge at all during the reviewed period. Outfall 001 may affect aquatic life and classified uses in state waters on a year-round basis. Because coal mining spoils spring water has been shown to be toxic in many cases, WET limitations and monitoring are necessary under the regulations. The same arguments are valid for imposing WET limitations and monitoring at outfall 007, which has an even higher flow -from 720,000 [0 1,940,000 gpd 30 day average discharge flow during [he period reviewed during permit renewal. This is a relatively new discharge for which there is relatively little monitoring history. The potential for toxicity from this discharge exists also.