Laserfiche WebLink
<br />Division of Minerals and Geology <br />9 November 2000 <br />Page 3 <br />during the active operation and reclamation periods for the facility. Accordingly the <br />applicant proposes to implement a groundwater monitoring plan to verify the presence or <br />absence of impacts to groundwater in the vicinity of the proposed facility. The key <br />elements of this groundwater monitoring plan are provided below. <br />Groundwater Monitoring Plan <br />A. Five groundwater monitoring wells will be installed as long screen water observation <br />wells. Each well will be installed between 40 and 70 feet deep depending on the <br />distance from the pit. Each well will include a slotted well screen from the bottom of <br />the well up to within approximately 20 feet of the ground surface. The wells will be <br />2 inch PVC installed within a minimum 4-inch diameter auger boring. A sand pack <br />will be installed in the annulus compatible with the well screen, and a bentonite seal <br />will be included in accordance with regulations. <br />B. The observation wells will be installed in two phases. Phase 1 will include two wells <br />installed within the permit boundaries. The first well will be located at the <br />northwestern corner of the Phase IV mining area. The second well will be located <br />within the Phase II area close to existing Colorado Highway 263 south of Balsam St. <br />These two wells will allow for establishing a groundwater baseline and for early <br />observation of groundwater level changes based on initial operation of the facility. <br />Phase 1 wells will be installed at least 12 months prior to initial dewatering at the <br />facility. <br />Phase 2 will include three wells installed north along Balsam Street. These wells will <br />be located where permission can be obtained and at distances of approximately 500, <br />1000 and 1500 feet from the pit. These wells will allow for long-term observation of <br />potential groundwater drawdown effects from the mining operation. Phase 2 wells <br />will be installed at least one month prior to initial dewatering at the Phase II portion <br />of the facility. <br />C. Observation of water levels is proposed for these wells as follows. <br />Phase 1 -Monthly for the twelve month period prior to initial dewatering at the <br />facility. Weekly for the first two months of dewatering activity at the Phase I, II, III <br />and IV mining areas, monthly thereafer until no significant changes in water levels <br />are observed, and quarterly thereafter until mining ends or "steady state conditions" <br />are realized. <br />Phase 2 -Once during the one-month period between well installation and initial <br />dewatering in the Phase II mining area. Weekly for the first two months of <br />dewatering activity at the Phase II, II[ and IV mining areas, monthly thereafter until <br />\\DEN\common\PROlECf5VA367 Grceley\Response to Tech Rev2.AOc <br />