Laserfiche WebLink
11)Following installation of the filter material, place a bentonite seal (chips) on top of the filter <br /> material to a minimum thickness of 3 feet. Add distilled water as needed to ensure proper <br /> hydration of the bentonite; <br /> 12)Fill remaining annular space with cement grout; <br /> 13)Complete well above-grade using a metal protective casing with locking cover; <br /> 14)Install 4' x 4' concrete pad (sloped for drainage away from the well) with 3" to 4" steel <br /> concrete-filled pipe bollards at each of the four corners. <br /> C—Topographic map—Please see attached(Attachment 4) <br /> D—Revised groundwater monitoring and sampling plans - <br /> If groundwater is encountered,proposed sampling plan is as follows: <br /> - Measure depth to groundwater. <br /> - Purge using new disposable poly bailer (minimum of three casing volumes prior to <br /> sampling). <br /> - Measure pH, conductivity, and temperature for each volume. <br /> - Purge until these parameters are stable and reproducible. <br /> Monitoring will be conducted quarterly for the first 18 months. If no groundwater is encountered <br /> sampling frequency will be reduced to semiannual with one sampling event occurring during the <br /> summer and other sampling event occurring during the winter. <br /> As proposed in the Groundwater Monitoring evaluation report (Attachment 3), if any <br /> groundwater were to be found during a sampling event, GCC intends to characterize it by <br /> analyzing for a broad suite to confirm the previous analyte list, including the following RCRA <br /> metals: As, Ba, Cd, Cr, Pb, Hg, Se and Ag. <br /> Additionally, GCC will amend its closure bond and mine closure plan to reflect the cost and <br /> method used to abandon and plug MW-006. <br /> E—Proposed Numeric Protection Limits (NPL) <br /> GCC proposes to maintain the numeric protection levels (NPLs) established by DRMS in your <br /> December 8, 2009 letter(Attachment 4): <br /> DRMS NPL <br /> TDS,mg/1 2630 <br /> Sulfate, mg/1 1950 <br /> R-226, PiC/1 23.5 <br /> R-228, PiC/I 12.3 <br />