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C~ <br />Mr. Steve Shuey <br />March 16, 1998 <br /> <br />Surface subsidence may eventually appear, as the fallen muck consolidates, allowing further <br />ground movement above it. However, if this were to occur it would take place over an <br />extended time period and should be limited to 12 inches or less of subsidence at surface. <br />Homestake will monitor the ground surface conditions above the adit on a quarterly basis. <br />Should any depressions be formed that could preferentially collect surface water, re-grading <br />of the ground will be conducted as appropriate. <br />Repeated saturation and draining of the ground around the adit up to the 9385 ft elevation <br />may result in some additional settlement of caved material. However, the overall magnitude <br />of the additional settlement is expected to fall within the range of uncertainty relating to the <br />ratio of the volume of loose rock and the volume of an equal mass of solid rock (i.e. the 20°~ <br />bulking factor), and is not an issue in terms of surface subsidence. <br />Thank you again for your timely review of our Technical Revision at the Bulldog reclamation <br />project. We trust that these responses to your comments are sufficient to gain final approval <br />of the Technical Revision for installation of an adit seal at the Bulldog 9360 level. If you <br />have additional concerns or questions, please contact me at your earliest convenience. <br />Very Truly Yours, <br />HOMESTAKE MINING COMPANY <br />Alan D. Cox <br />Corporate Manager - <br />Environmental Affairs <br />cc: A. Sorensen -Colorado DMG, Denver <br />D. Holmer -Colorado DOH <br />F. Martinez - Alamosa BLM <br />