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• No impacts aze predicted east of the South Platte River, which is located <br />approximately 200 feet east of the easternmost portion of the proposed expansion <br />area. <br />• A 4- to 5-foot mounding of groundwater west of the proposed expansion azea, <br />extending west approximately 1,000 feet, where the Lupton Bottom Ditch is <br />expected to reduce or isolate the effects of mounding. <br />It is predicted that the projected variations in groundwater levels will actually be less, due to the fact <br />that the model was based on the existence of a single slurry wall encircling the entire site, whereas the <br />mining plan indicates that sepazate slurry walls will be installed azound each mining phase. Therefore, <br />more groundwater will flow through the sight than is projected in the model. Impacts to wells and <br />irrigation in the shadow of the slurry wall aze addressed in the W WE report, and the report states that <br />the reduction in the aquifer resulting from the projected drop in groundwater level should not adversely <br />affect the production of wells in this location. Additionally, according to the report, there is no reliance <br />on subirrigation in the shadow azea. It does not appear that the projected mounding effects of the slurry <br />wall will negatively impact any residences, as there are none located in the more severe areas of the <br />projected mounding. <br />The Operator has committed to a monitoring program consisting of 14 monitoring wells in and azound <br />the site. The groundwater levels will be monitored monthly throughout the life of the permit. <br />Groundwater levels have been monitored since May of 2004 and will continue until a year's worth of <br />baseline data has been collected, prior to commencement of the new mining activities, to assure that <br />the model is based on accurate data. The Operator has also committed to monitor the vegetation in two <br />cottonwood groves located in the shadow of the slurry wall and of wetlands located both in the shadow <br />of the slurry wall and in the mounding azea to identify signs of stress to the plants. The Operator has <br />committed to commencing a groundwater investigation to determine the operation's effects on <br />groundwater should any of the following conditions occur: <br />• The groundwater level drops 2 feet below the 3-month average for the shadow area of <br />the slurry wall (each month's baseline level will consist of an average of that month's <br />reading and the previous month's and following month's readings), <br />• A complaint is received from a neazby resident, <br />• Vegetation in the vicinity shows signs of being stressed. <br />Results of the investigation will be submitted to the Division for review within 60 days of the initial <br />condition triggering the investigation. <br />The Operator has further committed to mitigation measures that will be implemented during the <br />investigation to rectify the condition triggering the investigation. If the condition is determined to be a <br />result of the mining operation, mitigation measures will be implemented, including: <br />• Construction of a pipeldrain to equalize groundwater levels, <br />• Release of water in ditches/laterals (Note: LGE will be proper agreements with ditch <br />an/or landowners prior to release of any release of water.) <br />• Well improvements (i.e. deepening an/or relocation) and(or well replacement <br />• Planting trees, shrubs, vegetation <br />