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iri-ii-ii~iiiiii~ii <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Deportment nl Natural Resources <br />131 f Sherman 51., Room ? 15 ^~~~~ <br />Denarr. Colorado BO?03 II <br />Phone: f tU 11 H66-3567 <br />FAX: (lUJI B7?~DIU6 <br />DEVARTMENT OF <br />February 6, 1998 NATURAL <br />RESOURCES <br />Mr. Rick Mills Roy Romer <br />Twentymile Coal Company co,e,nnr <br />29587 Routt Co. Rd. # 27 wmrs s ~ocnnead <br />E.ecmrve Dveaor <br />Oak Creek, CO. 80467 ti~~cnae~ s Eong <br />D~vis~on Director <br />RE: 1996 Annual Hydrology Report Review, Twentymile Coal Co., #C-82-056 <br />Dear Mr. Mills: <br />The Division has completed review of the 1996 Annual Hydrology Report for the Foidel Creek <br />Mine. We would like to commend you and your staff for doing an outstanding job of completing the <br />required monitoring program in accordance with the approved plan. Not only was the monitoring <br />frequency met at nearly 100% but the report was well organized, accurate and contained excellent <br />graphs, charts, and data tables. The discussion of the results was also well done, and provided, in <br />our opinion, an accurate analysis of what is occurring as a result of mining. <br />No impacts beyond those predicted in the Probable Hydrologic Consequences section of the permit <br />were noted after review of the data. The Wadge Overburden and the Twentymile Sandstone in the <br />Eastern Mining District appear to be dewatering as a result of mining and subsidence as predicted. <br />The impact to the Twentymile Sandstone appears confined at the present time to the general <br />proximity of the subsided azea. Wadge Overburden dewatering appeazs more extensive, likely due <br />to the greater degree of fracturing and rubblization. The Trout Creek Sandstone wells show no clear <br />impact due to mining, other than pumping dewatering. It is not cleaz at this time whether the <br />depressed water level in the Trout Creek in sections 29 and 30, TSN, R86W are a result of mining. <br />Mine inflow data does not suggest or otherwise indicate measurable flows from the Trout Creek [o <br />the workings. It is noted that mine water discharge has been reduced considerably from the past. <br />Surface water quality shows no significant changes from previously reported data and new maximum <br />values for various pazameters indicate no trend towards degrading water quality in the surrounding <br />area. The downstream site on Trout Creek (site 1005) TDS is well within predicted limits. <br />The Division has a few minor concerns regarding Map 13a and the water monitoring schedule. We <br />will handle these issues under the ongoing Permit Renewal process and/or in conjunction with <br />Permit Revision #4. <br />Sincerely, <br />Kent A. Gorham <br />Environmental Protection Specialist <br />CC: Dan Hernandez. DMG <br />