1996-01-23_HYDROLOGY - M1977378 (3)

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. - - III IIIIIIIIIIIIIIII 999 -37 � �Remediation Work Plan: Columbus Mine Portals Remediating Party: Sunnyside Gold Corporation P.O. Box 177 Silverton, CO 81433 contact William B. Goodhard Resident Manager Identification of Lands The Columbus mine portals and waste dumps lie immediately north of Animas Forks, San Juan County Colorado. See attached location and site map. Identification of the Waters of the United States Potentially Affected This property sits between the confluence of the Animas River and the West Fork of the Animas River. See attached location map. Physical Description of Conditions The area consists of; two mine portals and two waste dumps. The lower portal discharges onto the mine dump and percolates through it. The dumps are exposed to rainwater and snowmelt as well. The regional geology is volcanic rocks with narrow veins containing base metals; Fe, Pb, Cu and Zn. Sampling of the waters in this area indicate that even though the portal discharge is small, there is a substantial increase in dissolved metal loading to the Animas River. Description of Project The waste dumps need to be isolated from portal flows as well as stormwater events. The dumps will be regraded and hydrologic diversions installed to prevent run on conditions. The dumps would then be stabilized with basic pH material and revegetated to minimize percolation from stormwater events. The two portals will be opened and studied for the placement of hydraulic seals. In order for hydraulic seals to be placed, SGC feels that sites meeting the following conditions need to be found. 1) Location far enough underground to avoid the near surface fractures and joints caused by weathering. 2) Adequate rock compressive strength for structural stability. 3) A length of the tunnel with minimal faulting or other geologic features that may serve as a leakage pathway.