1996-07-16_REVISION - M1988112 - Laserfiche WebLink

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20 to 100 gpad Report to MLRD, additional monitoring implemented, pump from sump as required. 100 to 300 gpad Locate area of leakage, change pad loading/spraying to reduce leakage, pump from sump as required. 300-500 gpad Leakage area shutdown until leaks repaired. > 500 gpad Leakage area shutdown, replace primary liner. Pre4nant and Barren Ponds 0 to 20 gpad No response required. 20 to 130 caad Report to MLRD, additional monitoring required, pump from sump as requilred. 130 to 300 gpad Locate areas of leakage and operate ponds to minimize leakage if possible or repair. 300 to 3,000 gpad Repair leaks. . > 3,000 gpad Pond shutdown, replace primary liner. Section D.8 Project Water Balance Section D.8.2 Neap Leach Facility 44. The narrative explains the draindown from deactivated areas has teep estimated at 10 gallons per ton of ore with the remainder of solution ~ being held by capillary forces of the estimated field capacity of 12 percent moisture content. Pease discuss whether )aboratory 1 measurements were taken to verify either the 10 gallon per ton draindown or the remaining ]2 percent remaining moisture content of the ore sized material. If not, please consider doing so such that water balance and pond size design specifications can be verified, Response: A 12% field capacity moisture content has been derived from the laboratory testing program for the permeability test as the residual moisture content. This is discussed in Section D.3 and presented in Appendix D. Saturated direct shear testing has yielded a 20% moisture content for ore at near saturatipn levels. This number would not be realistic under field conditions in a heap leach situation. Under field conditions, the ore near the upper surface of the heap will be near the field capacity moisture content while the ore in direct contact with the pad