Laserfiche WebLink
b'Is. Erica Crosby <br />blay S, 2007 <br />Page 2 <br />2. The operator proposes a number of piezometers and monitoring wells. Please describe <br />how the wells will be reclaimed and include a reclamation cost estimate for abandonment of <br />the wells. <br />Response: Once one or more of the C-Pit pie~ometers and monitoring wells are no longer required, they <br />will be abandoned by a Colorado licensed water well driller in accordance with the Division of Water <br />Resourrer, Rule 16 Standards for Plugging, Sealing, and Abandoning Wellr and Boreholes. Surface <br />features including the concrete pads, traffic bollards, locking protective covers, and the uppermort five feet of <br />casing will be removed and dirposed as non-ha~ardaur solid wane. The borings will be grouted in place <br />using ahigh-solids bentonitegrout toground rurface ro the land may be used in a manner consistent with the <br />CEMEX reclamationplan. <br />The estimated cost to abandon and reclaim the six pieZometerr and five wells (existing well CEM-001 and <br />those proposed Jn TR-8) ir,~15,000. <br />3. The opexatox states that the data from the first phase of work will be used to refine the <br />current conceptual model for the C-Pit area, which will be used as the basis fox a proposed <br />long-term monitoring program fox the C-Pit. Please inform the Division as to the timing of <br />the submittal of a long-term monitoring plan. <br />Response: CEMEX propores to rubmit a long-term monitoring plan to the Division by August 1, <br />2007. This will be proposed as Technical Revision No. 9 to the Lyons Mine Permit M-1977-208. <br />4. The opexatox provided a table fox a single round of sampling proposed in this initial <br />phase. Please further explain the fxequenry of the sampling necessary in order to assess the <br />hydrogeologic conditions at the C-Pit In addition, please clarify the sampling frequency <br />and parameters to be analyzed for CEM-005. <br />Response: CEMEX will conduct the initial round of rampling of the wells proposed in TR-8 in May. <br />The data gathered from this initial phase of work will be used to refine our understanding of the current <br />hydrogeologic conditionr at this rite. The knowledge gained will be factored into the propored long-term <br />monitoring plan that will be used to monitor C-Pit and the rurmunding area once the eastern portion of the <br />pit is completely filled with inert shale fill. <br />CEMEX proposes sampling groundwater in monitoring wells CEM-001, CEM-002, CEM-003, and <br />CEM-004 in June and July, and factor the results from this sampling into the proposed long-term <br />monitoring plan to be delivered to the Divirian by Augurt 1, 2007 ar TR-9. <br />CEMEX propores to rample compliance well CEM-005 on a quarterly basis starting in May/June, <br />consistent with the current requirement to sample monitorzng well CEM-001 quarterly. If this sampling <br />confirms that there are no C-Pit related impacts at CEM-005, CEMEX proposer to educe sampling of <br />CEM-005 to an annual or semi-annual frequency. The proporal to reduce the sampling frequency will be <br />suppoKed by an estimate of groundwater flow velocity based upon information obtained in the TA-8 <br />hydrogeologic investigation. <br />Response to Adequacy Review - TR 8 C-Pitdoc <br />