2010-01-21_PERMIT FILE - M2009082 (11)

Home Browse Search

51859 Owner states that well has not been in service for at least several years, but may be used in the future for irrigation. Owner agrees that well would not likely be impacted, but requests baseline monitoring. Monitoring was initiated in February 2008 (Table 3). Prior to mining, to establish a baseline, Lafarge will measure water levels in the applicable private wells bi-monthly to quarterly, or as access is provided. After mining begins, and as access is provided, Lafarge will attempt to measure water levels in the applicable wells quarterly, until one year after mining. Measurements may not be recorded for wells that are actively pumping for irrigation or that have been significantly affected by recent irrigation. Reporting Prior to mining, Lafarge will prepare and submit a report on baseline groundwater levels, utilizing data from the 14 existing monitoring wells and any other private wells included in the monitoring program. Thereafter, groundwater monitoring data will be submitted quarterly to the DRMS as well as with the annual progress report submitted to the DRMS and copied to the Weld County Department of Planning Services. If Lafarge receives a complaint from a well owner, Lafarge will submit their groundwater monitoring data to the DRMS in accordance with the mitigation plan below. A copy will also be provided to the Weld County Department of Planning Services. Wells Within 600 Feet As discussed above, there is one permitted irrigation well within 600 feet of the proposed permit boundary. Lafarge will attempt to obtain a 600-foot well spacing agreement statement from the well owner at least six months prior to the commencement of the relevant mining phase. MITIGATION Monitoring data will be used to help identify potential changes in alluvial groundwater flows or elevations associated with mining and reclamation activities. Baseline data collected from the monitoring program will provide a range of water levels associated with pre-mining groundwater conditions. Experience at other sand and gravel mine sites in similar geologic settings, and baseline monitoring conducted to date, indicates that groundwater levels tend to fluctuate up to several feet per year, being highest in the summer and lowest in the winter and early spring. Due to normal seasonal fluctuations, Lafarge proposes to define the trigger point for potential mitigation procedures as 2 feet of drawdown relative to historic conditions. The amount of drawdown relative to the mitigation trigger point would be calculated and Lafarge West, Inc. - Parsons Mine 6 Groundwater Monitoring and Mitigation Plan