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z <br />constructed on bedrock that is erosion resistant claystone. This tlewatering volume will be pumped either <br />directly to recharge sites or to a settling pond. The tlewatering volume that is pumped directly to recharge <br />sites will recharge the natural groundwater table along the perimeter of the active mine to reduce the <br />potential local drawdown of the aquifer and subsequent impacts to local well users. The proposed method <br />of returning the tlewatering volume to the natural aquifer is via vertical "stand-pipes' as shown on Figure 3. <br />These perforated pipes are set into the upper portion of the sand and gravel deposit (above the natural <br />groundwater table) within a rock envelope to increase recharge rate capacity. The recharge water will filter <br />down through the unsaturated sand and gravel media and subsequently to the natural groundwater table <br />below. The tlewatering volume pumped to settling ponds will either recharge the aquifer at these locations, <br />be pumped to one of the recharge sites or be discharged off-site as surface water return to the river. <br />Water discharged off-site as surface water must meet monitoring and water quality standards determined by <br />the Colorado Department of Public Health and Environment Water Quality Control Division, per conditions <br />established in a Colorado Discharge Permit System (CDPS) permit. The United States Environmental <br />Protection Agency (USEPA) regulates the injection of water to groundwater aquifers via their Underground <br />Injection Control Program, administered locally (USEPA District 6) by Ms. Valois Shea. Ms. Shea was <br />contacted with regard to permit requirements for this project. She stated that a permit application should be <br />completed so that a final determination could be made as to the class of permit that would be required, but <br />that her initial thought was that no real contamination source is being introduced to the tlewatering volume <br />so that minima! water quality monitoring should be required. <br />4.0 GROUNDWATER MONITORING PROGRAM <br />The approach to the monitoring program is to include a broad scope of analytes with higher sampling <br />frequency at the beginning of the project (and prior to mining to the extent possible) to estimate background <br />conditions and then to decrease the frequency and number of analytes as the program progresses if the <br />initial program indicates little to no degradation of the groundwater quality. Following is a proposed <br />schedule for sample collection and groundwater quality parameters based on the proposed mining of the <br />south and north silt ponds in Mining Years 1 and 2, respectively. <br />Groundwater Monitoring Schedule (2-year) <br />Sampling Water Sampling Reporting <br />Event Date Levels Stnd ~ DQP z SDWA a Location(s)°'S Quarterly Annuall <br />OS-1 Oct-05 X X X X 1, 2, 4, 6, 7, 4Q 41 <br />05-2 Nov-OS X X X X All <br />OS-3 Dec-05 X X X X 1, 2, 4, 6, 7, 40, 41 X <br />06-1 Apr-O6 X X X X 1, 2, 4, 6, 7, 40, 41 X <br />06-2 Jul-06 X X X X 1, 2, 4, 6, 7, 40, 41 X <br />06-3 Oct-O6 X X X All X <br />06-4 Dec-06 X X X 1, 2, 4, 9,16, 41 X <br />07-1 Apr-07 X X X 1, 2, 4, 9,16, 41 X <br />07-2 Jul-07 X X X 1, 2, 4, 9,16, 41 X <br />07-3 Oct-07 X X X All X <br />Notes: 1. Standard Parameters include: <br />- pH (Field/SM2540-C) <br />- Temperature (Field) <br />- Conductivity (Field/5M 2510-8) <br />Groundwater Sampling and Analysis Plan October 2005 <br />Lup(on Lakes Project -2- <br />