2007-10-12_REVISION - M1977208 - Laserfiche WebLink

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INTEROFFICE MEMORANDUM TO: ERICA CROSBY FROM: DAVID BIRD -SENIOR GEOCHEMIST SUBJECT: CEMEX, LYONS QUARRY, M-1977-208; REVISED DATE: 10/12/2007 CC: CARL MOUNT Based on a telephone conversation 11 October 2007 with Mr. Al Notary of Brown & Caldwell, consultant to CEMEX Lyons Quarry, I have revised the memorandum of 5 October 2007 to address erroneous references that inaccurately stated that water quality regulatory limits had been exceeded for metals in ground water. Other conflicting statements have also been revised or deleted. Following are my REVISED comments on the Recommendations (Section 5) submitted 31 August 2007 by Brown and Caldwell as part of Technical Revision No. 8 for the CEMEX Lyons Quarry. Reduction of sampling frequency for C-Pit Water from quatterly to semi-annually Due to the history of constituents in pit water at concentrations exceeding regulatory limits, DRMS should requite at least five quarters of analyses with results below regulatory limits before approving this proposal. Eliminate dissolved thallium and chloride from the analyte list Because of the history of thallium and chloride detections at the site, eliminating thallium and chloride from the analyte suite would be premature. Thallium and chloride are regulated parameters, and should therefore be analyzed for five quarters, with results below regulatory limits, before DRMS approves their removal from the analyte suite. Continue to monitor the water level iu C-Pit Agreed Reduce the sampling frequency for monitor well CEM-001 Because of the existence of multiple parameters historically exceeding regulatory limits in pit water, DRMS should recommend that quarterly sampling continue for at least five quarters from the date sampling started. Monitor the water level at compliance well CEM-005 semi-annually. Agree, but if sufficient water is present in CEM-005, an attempt should be made to collect a sample.