2018-07-10_PERMIT FILE - M2018037 (4)

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Page 3 Mr. Mark Johnson May 30, 2018 shadowing affects will be minimized by the presence of the South Platte River on the east and northeast, the Lupton Bottom Ditch between the cells, and the drainage on the west site boundary. Dewatering of the unlined southeast cell will result in decreases in water levels around this cell. No wells are permitted within 600 feet of this cell. Area Wells and Sub-Surface Structures A review of permitted wells on file at the State engineer's Office(SEO), Division of Water Resources(DWR) indicates there are two permitted domestic wells within 600 feet of the permit boundary(not including the 5 monitoring wells). Both of these wells are screened in the alluvium. As mentioned above,the land owner owns the well that was formerly the Inouye domestic well. The other well, owned by L.G. Everist, is located north of WCR 14.5 on the northwest part of the mine(cross gradient of the mine). This well is 10 feet deep and is in the area of a demolished farm house. Review of the Weld County Tax Assessor files indicates there is only one sub-surface structure within 600 feet of the mine. This is the basement associated with the Inouye farm house now owned by the property owner. Mitigation Plan The site mining and reclamation activities are unlikely to adversely affect the two permitted area wells located within 600 feet of the mine. The former Inoyue well is owned by the property owner. The L.G. Everist well is cross gradient of the site and will likely be recharged from the relocated ditch to be constructed on the west side of the site. However, if the miner receives a complaint,the following mitigation plan will be implemented. The site monitor wells will be measured monthly to identify potential changes in alluvial groundwater flow or elevation associated with mining and reclamation activities. Baseline data collected from the monitoring program will provide a range of relative water levels associated with premining groundwater conditions. Experience at other mines in similar geologic settings has found that groundwater levels tend to fluctuate being highest in the summer irrigation season and lowest in the winter and early spring. If, during mining or reclamation,the relative seasonal groundwater elevation at any monitoring wells differs from baseline conditions by more than 2 feet, and the condition was not observed during baseline monitoring, or if the miner receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 30 days and notify the DRMS. After the DRMS has been notified,the miner will review the data and available information and submit a report to the DRMS within 30 days. The evaluation will include discussions with the well owner who has contacted the miner regarding a concern and review of baseline data from the well and vicinity to evaluate whether changes may be due to seasonal variations,climate, mining,slurry wall lining or other factors. The report will identify the extent of potential or actual impacts associated with the changes. If the extent of groundwater changes due to mining or reclamation activities is determined to be a significant contributing factor that has or may create adverse impacts, the mining associated impacts will be addressed to the satisfaction of the DRMS. Miner will begin implementing one or more mitigation measures if mining and reclamation activity is determined to be a significant factor to groundwater changes requiring mitigation.