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M1983-141 Amendment 2 Page 2 of 4 <br />feet. Ground cover is 65 feet. MRV proposes anon-reinforced concrete plug with a total <br />length of 6 feet or less. Perimeter grouting, if necessary, will be minimal. <br />MRV will design these bulkheads fiuther to an adequate safety factor, considering <br />available technology, maximum credible earthquake influence, and other site factors <br />applicable, as per Exhibit D of the amendment application. <br />2. Ground water sampling data. <br />To be provided by Mark Steen. <br />3. Ore and waste handling, including mining method. <br />MRV would like to reference Exhibit C -Mining Plan, of the amendment application <br />(attached). <br />This is a very simple operation. Ore is removed from the mine via 1 ton rocker-dump ore <br />cazs. This material is placed in a steel ore bin (container) neaz the terminus of the mine <br />rail at the surface. The material is then drawn from the ore bin into a four wheel drive <br />dump truck which transports the ore to the mill. The ore is dumped into the steel, <br />sheltered bins at the mill (permit M-1994-117). Any metallic minerals in the ore aze <br />captured as a bulk concentrate product or a gravity concentrate, which is bagged in <br />"super-sack" style containers, and stored in the mill building until off-site shipment to a <br />smelter or refining facility. Gangue material in the ore is pumped as slurry to the <br />permitted, double lined tailings impoundment at the mill. <br />The mining method utilized (know as "resuing" or "stripping") is a time proven method <br />for narrow vein ore extraction, minimizing the extraction of waste. Waste material will <br />be left as stope fill underground. Any waste removal from the mine workings necessary <br />to accommodate swell, including any waste generated by development will be removed <br />from the mine in the same manner as ore and will be stockpiled in a terraced mine dump <br />area. This material will be inert, Bou]der Creek or Idaho Springs Granite with little, if <br />any vein material. Again, the object of this type of mining is to maximize shipment of <br />the vein material to the mill for processing, not waste it in dumps. Appropriate drainage <br />and storm water controls will be utilized as described in the operation's Storm Water <br />Management Plan using Best Management Practices. <br />Geologic Structure <br />The Cash and Freiburg veins, along with all other veins in the Gold Hill area generally <br />strike NE-SW. These veins aze narrow (0.1 to 4.0 feet), steeply dipping (vertical or <br />within approximately 20 degrees of vertical) epithermal fissure fillings. The low <br />temperature/pressure deposition in these hydrothermal veins caused minimal alteration to <br />the adjacent wall rock. The sericitic alteration typically extends one (1) foot or less on <br />each side of the vein. Wall rock is Boulder Creek granite with minor occurrences of <br />Idaho Springs schist/gneiss and dikes of pegmatite, aplite, biotite/latite. Typical ground <br />