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<br />a gravity-draining system with no mechanism of removing fluid other than by gravity. In <br />publishing the Final Rule for leak detection systems serving hazardous waste impoundments <br />(which, of course, a cyanide leach is not), the EPA states that action leakage rates are those that <br />exceed the rate at which the leak detection system (in the Cresson case the Low Volume Solution <br />Collection System) can remove without producing an inappropriate head on the lower liner <br />(Federal Register, January 29, 1992 - 40 CFR 260 et seq). Of course the Cresson Leach <br />Facility, as do most valley leach facilities, has a Low Volume Solution Collection System which <br />does not depend on gravity for drainage but which is pumped at essentially any rate that one <br />selects. The pumping maintains the head on the lower liner at an appropriate level. Only if the <br />pumps aze inadequate to remove fluid such that the head on the lower liner rises uncontrollably, <br />is CC&V in a situation similaz to those the EPA assessed. <br />We also point out that the EPA considered a mix of responses to higher leakage rates and did <br />not state that any one response was appropriate to any particulaz action level. <br />CC&V believes that the principal criterion for determining a need for any action is whether the <br />LVSCS can be operated to remove fluid above the lower liner of the PLS at a rate that maintains <br />the head on the lower liner below a level that limits flow through that lower liner. Though <br />CC&V believes the current potentiometric head limitation in the Permit applies to the Ore Liner <br />System, it is considered appropriate for the same criterion to apply to that portion of the lower <br />liner beneath the PLS above the pump sump. This translates to maintaining a head of less than <br />13 feet on LVSCS Pump #2 or less than 12.5 feet for LVSCS Pump #1. <br />this satisfies the request of Dr. Pendleton and you. If it does not, please let us know. <br />E. <br />Environmental Affairs <br />Attachment 1: Golder Associates letter dated May 24, 1995 (5 pp). <br />FILE: CC&VSTIP.004 <br />