2010-02-02_HYDROLOGY - M1977208 - Laserfiche WebLink

Home Browse Search

//CC-MC-X FEB 0 2 2010 DiAVin ar i--ec+amation, Mining and Safebj February 1, 2010 Mr. Allen Sorenson via certified Mail 7007 2680 0001 6296 0354 Environmental Protection Specialist Return Receipt Requested Division of Reclamation, Mining and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 Re: CEMEX Lyons Mine Permit M-1977-208 Technical Revision No. 10, C-Pit Hydrogeologic Investigations 4th Quarter 2009 Monitoring Data Dear Mr. Sorenson: In keeping with the requirements of Technical Revision No. 9 to Permit No. M-1977-208, this letter transmits surface water and groundwater data from sampling the C-Pit pond and related wells for the fourth quarter 2009. In November, 2009, CEMEX personnel sampled the water in the pool at the north end of C-Pit, as well as groundwater from monitoring well CEM-001, the nearest well, and alluvial well, CEM-004. CEMEX also monitored the water elevation in C-Pit and in CEM-001. Please refer to the text, figures, and appendices of the C-Pit Hydrogeologic Investigations report (Brown and Caldwell, August 31, 2007) for site details, well construction, and related historical information. As documented in prior reports, CEM-005 was discovered to be collapsed in March 2009. Current plans for the collapsed well include abandoning as per Colorado State requirements as weather allows spring 2010, and completion of an abandonment report with a copy submitted to your office. Referencing the 1998 hydrologic model, the absence of water in CEM 005 prior to collapse, and the lack of any other indicator(s), we continue to conclude that the migration of water and/or any potential contaminant components in waters whether from C-Pit or other up- gradient sources to the Dakota Sandstone or Fort Hayes Limestone is not expected. The C-Pit pond water and groundwater samples taken in November were analyzed for pH, chloride, sulfate, dissolved solids, dissolved selenium and dissolved thallium. Table I summarizes the results and the prior quarterly sampling results for 2009. The most recent analytical laboratory reports are enclosed with this letter as an attachment. CEMEX continues to monitor the water elevation in the C-Pit pond visually after the data logger recording head became unusable and was removed from the pit in June 2009. C-Pit water has not been used in the plant process since October 7, 2009. Pumping of process water from C-Pit did occur intermittently for cooling water between April 2009 and October 7, 2009. Water levels in the third quarter of 2009 showed a rise of approximately three feet over the second and third United States Operations P 0 Box 529, Lyons, CO 80540, USA, Phone (303) 823-2100, Fax (303) 823-2199