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1 <br />processed through the carbon-in-leach circuit. Once the <br />concentrates have been processed through the carbon-in-leach <br />circuit they will be combined with the tailings for disposal. <br />This is discussed in Section D.5 of the permit application. A <br />textural analysis of the total material after combination of the <br />tailings and the concentrates is presented in Appendix D. <br />1 Exhibit D, Section D.5 revised 2/15/89 and corrected 4/20/89. <br />17. Wi11 the flotation system also use cyanide as part of its processing <br />prior to disposal as tailing? <br />' Response: The tailings material will not be exposed to cyanide as part of <br />its processing. The concentrates will be processed through the <br />carbon-in-leach circuit and will be combined with the tailings <br />prior to disposal. The process is explained in detail in Section <br />D.5 of the permit application. <br />No application change necessary. <br />' 18. The concentrates from the carbon-in-leach circuit should be rinsed to <br />reduce the level of free cyanide to 0.2 ppm. This concentration is the <br />Colorado ground water receiving standard for free cyanide and appears <br />to be most appropriate for the San Luis Project. It is our opinion that <br />the ground water standard is most appropriate because the potential for <br />post-rec]amation effluent to flow to Culebra Creek is minima). <br />' Infiltration into the colluvial/alluvial materials would probably be <br />the most Likely flow path for any effluent. <br />Response: BMR will commit to achieving a level of 0.2 ppm free cyanide in <br />the combined tailings/concentrate material at the point of <br />disposal. <br />' While BMR will obtain the level of n.2 ppm free cyanide in the <br />combined concentrate/tailings at the point of disposal, they do <br />not believe the ground water drinking water receiving standard <br />is the appropriate reference for determining the levels for <br />neutralization. In the area of the leach pad and mill facilities, <br />ground water has been measured at 400 below the surface (see <br />Exhibit G). The bedrock overlying the ground water is Santa Fe <br />Conglomerate which has been measured at permeabilities on the <br />order of 106 to 10"' cm/sec. In addition, the alluvium/colluvium <br />in the project area lies in an undesignated groundwater basin for <br />which standards have not been determined. <br />Exhibit D, Section D.5 revised to reflect this information 2/15/89. <br />' Section D. 6.2.2 Geochemical Characteristics <br /> <br />LJ <br /> <br />