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<br /> <br />Golder /tssoclates Inc. <br />200 Union Boulevard. Style 500 <br />lnkewood. CO USA 80228 <br />telephone (303) 980-0540 <br />Fax (303)985-2080 <br />March 22, 1996 <br />Cripple Creek & Victor Gold Mining Company <br />2755 State Highway 67 <br />Victor, CO 80860 <br />RE: REMEDIATION OF UNDERGROUND WORICL~IGS <br />Dear Ron; <br />Our Ref: 943-2847.001 <br />As identified in an April 12, 1995, letter from Golder Associates [nc. (Golder) to the Cripple Creek <br />& Victor Gold Mining Company (CC&V) titled "Assessment of Potential Influence of Old <br />Underground Mine Workings On The Design of the Phase II Leach Pad," historic underground <br />workings are located within the limits of the Phase II Pad. While the surface appears suitable as a <br />foundation macerial for the Soil Liner Fill, the potential collapse of a shaft or tunnel could result in <br />a depression and the elongation capabilities of the geomembrane exceeded. Therefore, Golder <br />made preliminary recotrmtendations in the April 12, 1995 letter [o address these issues. <br />Two tunnels were identified within the limits of the Phase II Pad: the Gold Dollar tunnel and the <br />Woods tunnel. As a means of remedia[ing the tunnels, Golder recommended that the tunnels be <br />excavated so that a minimum of 20 feet of bedrock separate the tunnel from the top of the structural <br />fill. During the construction of the Phase [I Pad, both the Gold Dollar and Woods tunnels were <br />located, excavated and backfilled as recommended. <br />Six additional underground workings were identified within the limits of the Phase II Pad based on <br />the review of historic records. These workings include the Raven Beacon shaft, Lit[le Nell N2 <br />shaft, Little Nell il3 shaft, Ore House shaft, Old shaft and Harcourt shaft. <br />As part of the remediation activities associated with the shafts, Golder initially recommended that a <br />concre[e cap be constructed over the center of the shaft. More recently, Golder has developed an <br />alternate capping system using geogrid that provides for the following: <br />- spans a potential depression resulting from a ten foo[ diameter shaft; <br />- minimizes the strains imposed on the geomembrane and geogrid; <br />- provides long term support: and, <br />- minimizes the layers of geogrid required. <br />• ~II ~I~~II~I~~~~~~II <br />nn ^^ sss <br />~__~ Wl~~ <br />ASSOC1c11ES <br />OFFICES IN AUSTRALIA. CANADA. GERPAANV. 4LNGARV, ITALY. SNEDEN, UNITED KINGDOM. UNITED STATES <br />