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<br />Limited Impact Permit Amendment Application for the Cash Mine, <br />1985. Indicated ore source is the Mogul mine, which is not <br />currently permitted for production, and not currently a Boulder <br />County approved source of ore for milling at this location. <br />Haphazard editing has led to odd references to this mill being <br />located as close as possible to its ore supply, with examples of the <br />Cash and the Whv Do, neither of which are current sources of ore <br />for the proposed operation. Awater-measuring device mentioned <br />as installed at the pipeline diversion point does not exist; the <br />property over which the pipeline runs is owned by Gold Hill <br />Mines, not COM, Inc.; responses to Exhibit B requirements seem <br />to be interspersed with much other material so that evaluation is <br />rendered difficult. <br />(c) Exhibit C - Minine Plan: Little relevant material has been <br />submitted under this category. Discussion of the tailings <br />impoundment is completely inadequate since it refers to the design <br />originally proposed in the Cash Mine permit amendment <br />application noted th (b) above. This design was significantly <br />modified as a result of discussions with MLRD staff, but no <br />revised engineering was ever submitted. A key item of this design <br />was installation of an impermeable plastic liner in the tailings <br />impoundment. importarrce of this liner was underscored by Ted <br />Zorich & Associates (referedce above) and by this Committee in <br />our letter of September 23, 1985 to the MLRB citing review by <br />Mr. Jack Laughlin, RPE, and Dr. William Page, geologist, and <br />their concurrence with the liner approach. Presence of this <br />impermeable liner in the tailings pond affects the profile of the <br />phreatic surface within the impoundment and significantly limits <br />engineering options for additional tailings emplacement. An option <br />for removal of existing tailings deposits to some remote location is <br />mentioned but never discussed; at a minimum, the engineering <br />requirements for material removal while maintaining liner integrity <br />must be specified, as must the requirements for sequestration of the <br />tailings from the environment in their new location. Presumably <br />some regulatory agency other than MLRD would be involved in <br />oversight of the fmal disposition of those materials; this agency <br />should be identified and contacted as appropriate. <br />Water use and water balance issues are sketchily addressed; no <br />engineering estimates are provided of actual yearly average and <br />worst-case water evaporation loss rates from the tailings <br />impoundment, nor is there any comparison between these rates and <br />the required net water throughput for the mill at the design <br />maximum milling rates. The implied net use rates are quite low <br />and require extensive recycling of process water. Such recycling <br />