2009-07-06_REVISION - M1977036 (40)

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EXHIBIT G Water Information General Mining at the Lafarge Brown property will intercept shallow alluvial groundwater, which typically lies 9 to 13 feet below ground surface. Deeper bedrock aquifers that may underlie the site will be unaffected by the mining operation due to the shallow depth of excavations and low permeability bedrock strata beneath the shallow sand and gravel. A Groundwater Monitoring and Mitigation Plan is provided (Attachment G-1) as a guideline for monitoring and mitigation measures. Pertinent groundwater features within and around the site are discussed and illustrated in the Groundwater Monitoring and Mitigation Plan and in Exhibit C. Mining will occur south of the Cache La Poudre River. The various mine phase areas will be dewatered by the use of perimeter drains. All water collected as part of the dewatering will be discharged into drainage ditches and ponds then into the river via discharge points at the existing mine. Upon completion of mining, the site will become part of a larger unlined pond that will also cover properties of the existing permitted area to the east and south. Potential Water Resource Impacts The Lafarge Brown mining operation is projected to have minimal impacts on water resources in the area. Due to the relatively thin gravel deposit, shallow excavation, phased operation, and natural and hydrologic boundaries and barriers, a rather limited extent of drawdown due to the mine dewatering operation is projected beyond the Lafarge Brown Property. As addressed in the Groundwater Monitoring and Mitigation Plan (Attachment G-1), the site hydrogeology indicates that no existing permitted private wells would be significantly affected by the mine operation mainly due to the hydraulic barrier of the Cache La Poudre River and the distance of wells from the site. Discharge Permits The proposed mine will be dewatered and operated as a dry mine. Alluvial groundwater from the dewatering will be discharged to the Cache La Poudre River. The existing CDPES (discharge) permit for the 35th Ave mining operation will be amended to include the Lafarge Brown property. The discharge rate will vary seasonally. Surface Water and Stormwater Management The applicant has a stormwater management plan for the mine to the east and south. This plan will be amended to include the Lafarge Brown property. In Colorado, storm water discharges are covered under the general discharge permit. As stated previously, the existing discharge permit will be modified to include the Lafarge Brown parcel. The Stormwater Management Plan is included as Attachment G-2. Greeley 35th Avenue Mine (M-1977-036) DRMS 112 Reclamation Permit Amendment Application PA2351N33-23511-08005\Deliverables\DRMAApplication Package\Exhibit G\Exhibit G 06-05-09.doc Page GI of G3