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~ III IIIIIIIIIIIII III MINED LAND RECLAMATION DIVISION Department of Natural Resources 7313 Sherman St.. Room 275 Denver. CO 80203 303 866-3567 Rpx 303 832-8106 of ~o< New['~ +: ~g :~ r8 ]6 ~ Roy Ramer. Governor Michael B. Lang, Dnr~s~on Drteaor September 15, 1992 Mr. Robert Williams Harrison Western Corporation 4860 Robb Street, Suite 101 Wheat Ridge, CO 80033 Re: Diversion Ditch, G.E.C. Mine, C-81-037 Dear Mr. Williams, You have requested our evaluation of the placement of the diversion ditch draining the undisturbed drainage west and south of the West Pit at G.E.C. The diversion, as installed in July, represented the logical placement of the ditch between the natural drainage and the Magpie Creek Diversion; it was the shortest distance between those two points, it interfered insignificantly with the footprint of the pond, and resulted in mixing of a very small area of disturbed area drainage with the undisturbed watershed drainage. The August, 1992, storms suggested one weakness with the location, namely, the possibility of underground workings existing below the outfall with the Magpie Creek Diversion. The development of a hole in the inadequately armored outfall into which water from the culvert drained could have serious repercussions to the area's hydrologic balance. Movement of the outfall of the diversion ditch may result in a similar problem, as historic mining maps did not show workings in this location. As a consequence, the Division recommends that Harrison Western propose a long-term, permanent solution to stabilize the outfall and the Magpie Creek Diversion. STAT~OF COLORADO In conclusion, the Division finds that the diversion placement is acceptable, but that stabilization of the outfall and the surrounding Magpie Creek Diversion bottom is required.