2009-04-20_HYDROLOGY - M1977208 - Laserfiche WebLink

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a ?I6? ZZCGMGX Apri16, 2009 <r. Alan Sorenson Environmental Protection Specialist Division of Reclamation, Mining and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 Via Certified Mail 7007 2680 0001 6365 9288 Return Receipt Requested .? Re: CEMEX Lyons Mine Permit M-1977-208 Technical Revision No. 10, C-Pit Hydrogeologic Investigations t Quarter 2009 Monitoring Data Dear Mr. Sorenson: This letter transmits surface water and groundwater data from sampling the C-Pit pond and related wells, in keeping with the requirements of Technical Revision No. 9 to Permit No. M- 1977-208. On February 5, 2009, CEMEX 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 the alluvial well, CEM-004. CEMEX also monitored the water elevation in C-Pit and in CEM-001, and measured the depth to water in compliance well CEM-005 located approximately 2,700 feet southeast of C-Pit along Hygiene Road. 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 information. CEM -005 As discussed in our phone notification, CEM-005 has collapsed. Depth to water was measured on February 5, and found at approximately 60 feet from ground surface. We do not know when the collapse occurred. Subsequent investigation involved an attempt by John's Well Service to camera the well. The water was too murky to produce suitable camera results. The baler that had been left in place in the well is stuck somewhere below 150'. Pieces of plastic casing and silty slurry were recovered from the well. A review of the geophysical data collected during the logging of the well suggests the potential for clay seams at the 150-170' interval that may be responsible for the collapse of the well. The well is terminated in the Fort Hayes Limestone at approximately 400-foot deep. The agreement of TR-9 was to monitor water depth at CEM-005 on a semi-annual basis, and in the event the well shows signs of increased water volume sufficient to sample, an attempt be made to obtain a sample. Per our conversations, we do not have evidence to believe the water present in the well at this time is from the Fort Hayes Limestone, and as such, have not analyzed any samples. The water level is more representative of a localized perched water table. Lyons Plant P.O. Box 529, Lyons, CO 80540. USA, (303) 823-2100, Fax (303) 832-2199