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<br />Golder Associates Inc. <br />n,: Union 3auiwcr~, Sui~e 3~~ <br />LakawooQ, CO USH. 80225 <br />taiaphons (303) 98GC5ep <br />ax (303} 95.~r208o <br />April 12; 2002 <br />Cripple Creek & Victor Gold Mining Company <br />P.O. Box 191 <br />2755 State Highway 67 <br />Victor, Colorado 80860 <br />Attention: Mr. Ron Roberts <br />RE: PHASE IVA SOLUTION COLLECTION PIPIltiG <br />Deaz Ron: <br />~_° _ ~oic~~r <br />ASS©(~~~5 <br />Our Ref: 003-2205 <br />Golder Associates Inc. (Golder) has prepared this letter in response to your e-mail dated <br />March 21, 2002 regazding the removal of the solution collection piping from within the <br />Phase IVa footprint. According to your e-mail, the CC&V Process Group has evaluated the <br />need for solution collection pipes in this azea and has determined that they will not be <br />required for the collection of leach solutions in the Phase IVa azea. In your e-mail, you <br />requested Golder to assess the potential geotechnical issues associated with removal of the <br />solution collection pipes. <br />In our opinion, the primary geotechnical issue related to removal of the solution collection <br />piping is the hydraulic head on the liner: However, based on the available data, we do not <br />anticipate the hydraulic head on the liner to exceed % fee*. in the Phase iJa area because of <br />the following: <br />Laboratory tests have been conducted to assess the hydraulic conductivity <br />of the Drain Cover Fill (DCF) under the maximum ore height. The results <br />of these tes*s indicate t'tat the hyd-aulic coaductivi y of the DCF is <br />approximately 0.1 centimeters per second (cm/sec), which is considered to <br />be high enough to minimize mounding of leach solutions on *.he liner; and <br />2. The majority of the Phase IVa area is graded steeper Than approximately <br />20 percent. This grade, combined with the permeabili~y of the DCF, is <br />considered to be high enoush to prevent building a hydraulic head greater <br />than Z feet on the liner. One portion of the Phase IVa azea is graded IIatter <br />than 20 percent. In our opinion, the permeability of the DCF is high <br />enough to minimize building a hydraulic head heater than 2 feet in this <br />azea. <br />Based on this information, Golder believes the hydraulic head in the Phase IVa azea will be <br />less than 2 feet, even if the solution collection pipes are removed. <br />