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~ ~ -T~ a~ _~~ i STATE OF COLORADO DIVISION Of MINERALS AND GEOLOGY Department o(Namral Resources I~~~~~~~~~ 1313 Sherman 9., Room 21 S Denver, Colorado 80203 Phone: (3031 866-3 567 FAl(: (3D3) 832-8106 DEPARTMENT OF Friday, June 9, 1995 NATURf~L, RESOURCES Murari Shrestha Mi Roy Romer . Governor Western Fuels Colorado dames S. Lochhead 405 Urban St. Executive Director Suite 305 ""`hde` s. `°"s Division Director Lakewood CO 80228 RE: New Horizon Mine (C-81-008), Reduction in Monitoring Technical Revision, TR-24 Dear Mr. Shrestha: The following are the results of the Division's review of the technical revision submitted by Western Fuels -Colorado for the New Horizon Mine Nos. I & 2. In this revision Western Fuels - Colorado proposes to reduce the water monitoring at the New Horizon #1 and #2 mines. This revision will delete some monitoring locations and reduce the frequency and water quality parameters that are monitored at others. The reductions are requested because ongoing monitoring at the New Horizon Mines #1 and #2 have not shown that mining has adversely effected the hydrologic balance and that the reduction of monitoring will not hinder detection of potential adverse impacts to the hydrologic balance at these mines. The review of this revision request was conducted jointly with Harry Ranney. The Division concurs with the majority of the request but there are areas that will require some modification. The areas of concern are in bold type. The revision was submitted as replacement pages to the current permit application with a cover letter briefly describing the reason for the proposed changes. The following are the results of the Division's review with comments. Currently 14 wells (from table 15-20) are monitored at the #1 mine and this revision proposes to delete 5 welts. Two wells (GW-N1P1 and GW-N4R) are proposed to be deleted because they are close to other wells that are monitored there monitoring is duplicated by other wells. The Division concurs with this proposal. There aze three other wells (GW-N10, GW-N26 and GW-N28) that are proposed to be deleted. These wells are spoils wells that have bee istoricit dry. Currently these wells are monitored monthly for field parameters. The Division does not concur with this proposal. These welts are needed to monitor the establishment of a potential spoils aquifer. However, the field monitoring may be reduced to annually for field parameters and if water is found in these wells the monitoring frequency should be increased to monthly.