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~~ ~~ <br />At the heap and pond area, it has been demonstrated that the water <br />table is at least 400 foot below ground surface. The intervening <br />material, the Santa Fe Conglomerate thinly overlain by colluvial <br />materials, has poor water transmission capabilities. The hydraulic <br />conductivity (ability to transmit water) of the Santa Fe conglomerate <br />is estimated to be 10-5 to 10-~ cm/sec. Discharges from the <br />secondary liner could infiltrate the subsurface, and travel to the <br />southwest, generally following the flow of the surface Arainage, The <br />ground water flow would continue to the west toward Ritco Seco. It is <br />uncertain whether this flow would actually intercept then Rito Se co <br />al]uvial aquifer system or be lower in elevation and pa<.~s below. Due <br />to the slow travel time involved, and the confined nature of the <br />initial flow path area, ground water flows could be intercepted prior <br />to reaching the plains area west of the mine site. It its also <br />expected that dilution and attenuation due to chemical toonding with <br />soils materials will tend to greatly reduce the amount cof cyanide in <br />the waters. Moreover, any solution which would be available for <br />groundwater transport must pass through the heap or ponds leak <br />detection system, where it would be observed, thus allowing for <br />appropriate reaction. <br />Upon completion of leaching operations, the heap and ponds will be <br />detoxified. The goal of the detoxification program is 'to reduce the <br />level of free cyanide to 0.2 parts per million (ppm). Effluent from <br />the heap after reclamation is complete cannot exceed 0,2 ppm. To <br />achieve this goal, a cyanicide, such as hydrogen peroxide, will be <br />added to the ponds. This solution will be recirculated through the <br />heap. In addition, fresh water will be added to the system to <br />encourage flushing of any residual sodium cyanide solution. When <br />detoxification is complete, the remaining now detoxified solution, <br />will be evaporated from the site. <br />Geochemical testing of ore samples exposed to the leaching process <br />have shown that post leaching metals mobilization will mot occur. <br />The permit document contains an emergency response plan which will be <br />placed at various areas at the mill and heap. This plan details a <br />number of emergency situations dealing with sodium cyanide and other <br />chemicals, and describes appropriate responses to be undertaken by <br />on-site personnel. A copy of the emergency response plan is attached. <br />Miscellaneous Concerns <br />A number of other public health and safety concerns have been addressed in the <br />permit. These are: <br />- The heap and pond area will be fenced so as to discourage public <br />access; <br />- Signs will be placed on the fence warning the public of the use of <br />sodium cyanide. These signs will be printed in Spanish and <br />English; <br />- The mill area will be similarly fenced and signed; <br />- Explosives will be used and stored in accordance with Colorado <br />Division of Mines regulations; <br />-6- <br />