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iii iiiiiiiiiiiu iii <br />99 <br /> STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Oepanmem of Natural Resources R <br />~~"~ <br />1313 Sherman St.. Room 215 `d <br />Denver, Colorado 80203 I <br />~~ <br /> <br /> <br />Phone: 13031 86h-1567 . <br />II <br />FAX:1307)832-8106 <br /> DEPARTMENT nF <br /> NATURAL <br />June 9, 1994 ~S~UR~-ES <br />Ruy Rumei <br />Mr. Ralph Lopez c~~rrn~r <br />Environmental Engineer wmrss fuchhrs~ <br />f xrnnrve U~~ennr <br />Basin Resources, Inc. <br />14300 Highway 12 Michael B. Lnng <br />Uiviaun Uirec br <br />Weston, CO 81091 <br />RE: Adequacy Review, Technical Revision No. 34, New Elk Mine, <br />Permit No. C-81-012, Basin Resources, Inc. <br />Dear Mr. Lopez: <br />The Division has reviewed Basin Resources' May 11, 1994 adequacy <br />response submittal and has the following questions. <br />1. In the May 11, 1994 adequacy response submittal from Basin <br />Resources, in section B. 2., it is stated that "vertical <br />communication between the overburden and the underburden <br />appears to be limited" and that mine inflows had not been <br />correlated with any faults. It is apparent to the Division <br />that certain mine inflows are, however, associated with <br />faulting. Map 5, "Geology", of the permit application shows <br />an east-west striking fault that appears to coincide with an <br />east-west trend of mine inflows. (These inflows are numbered <br />10, 11, 12 and possibly 9, on the mine inflow surrey map in <br />appendix 3, page 67 of the 1988 water year Annual Hydrologic <br />Report. <br />In addition, according to Greystone's submittal of May 11, <br />1994, the Raton formation, where the Allen seam is located, <br />contains a small number of water bearing zones of limited <br />horizontal extent. The only large aquifer is the Trinidad <br />sandstone, a regional aquifer that lies 500 to 900 feet below <br />the Allen coal seam. Yet, as reported in the AHRS for New <br />Elk, mine inflow at points 9, 10, 11 and 12 have totaled 70 to <br />99 GPM each year from 1984 through the 3rd quarter of 1989, <br />when the New Elk portals were sealed. <br />The Division believes that this relatively high rate of mine <br />inflow at these four points can not be fully accounted for by <br />a scenario of a geologic cross section that has no <br />intercommunication of water bearing zones. Rather, the <br />Division believes that a more probable scenario is one where <br />faulting has provided intercommunication of the mine workings <br />