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Section D.7.3.2 Geochemical Characteristics 25. Please describe the processing and rinsing methods, concentration of chemicals utilized, duration, etc. of the heap material prior to water quality analyses for geochemical characterization. This information would be useful in determining post leaching effl uent quality limitations. Section D.7.4 Heap Leach Pad Design and Construction Section D.7.4.1 Pad Area 26. The narrative specifies that the heap pad area will be approximately 1500 ft, by 1500 ft. (2,250,000 square ft. or approximately 5? acres). The associated table shows a total pad area of 43 acres. Please clarify. 27. Description of the pad stage connections explains that surface flows will drain from one stage to another through spillways installed in the interstage berms, and ultimately into the pregnant pond. However, the Heap Plan View, (Figure C-8), and the Heap Cross Sections (Fi~lure C-9), indicate that the heap will be a uniform surface, draining along the center drain and perimeter berms. Please clarify. 28. The secondary liner is proposed to be a 12-inch thick natural soils amended with bentonite to achieve a permeability rating of 1x0-6 cm/sec. It is recommended that a compacted soil or clay not tie used as a secondary liner as any flows reporting to the leak detection ~:ystem may cause erosion of the underliner along its flow path. A geomembrane liner is recommended for use as a secondary liner. Please address, specifically discussing potential secondary liner damage, and proposed methods of repair should failure occur. 29. The permit application states that the "target permeability" cf the compacted soil liner is 1x10-6 cm/sec. Although we do not recommend the use of a compacted soil liner, if one is employed it must achieve a permeability of 1x10-6 cm/sec. It will be necessary to submit ~~ documentation that this permeability has been achieved prior to placement i`- of the upper liner. '~ 30. The primary 60-mil HDPE liner extending to the heap and pond Perimeter berms, illustrated on figure C-8 and further detailed in Figures C-9 and C-10, should be anchored such that the liner extends along the interior surface of a "U" shaped ditch, thus providing additional anchoring security. Please address. 31. Solutions are to be pumped to and from the mill in pressure-tested welded pipe. Although the pipelines are not shown, a facility pipeline corridor is noted on Exhibit C-10. a. As this area can potentially come into contact with concentrated cyanide solution, the pipeline corridor should be lined with HDPE. A design should be submitted including the details at the haul road crossing and mill building entrance location. -5-