2021-08-27_REVISION - M2019028 - Laserfiche WebLink

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J-2 Contracting Co.—DPG Pit— Technical Revision No. 1 Adequacy Review Response File No. M-2019-028 -3- Response: The DCP line is to be abandoned when Chevron (Formerly Noble) permanently abandons Well 1-9H5 Weld County(currently shut in per COGCC website) in the next two (2) years. This well is on their abandonment list according to what Chevron has provided to J-2 Contracting, Co. (J-2). J-2 has been working with Chevron to get an official agreement but a signed agreement has not yet been reached. J-2 commits to continuing to work with Chevron and DCP to obtain an agreement from the parties prior to mining through the easement. 6. On revised Exhibit C-4 — Mining Plan Map the map indicates a recharge pond, a secondary recharge pond and an overflow pond. The description for the purpose and function of these features could not be found in the approved permit application documents by the Division. Please indicate where in the approved permit application the function of the features are described or provide a description for the purpose and function of these features. Response: The description for the purpose and function of these features is as follows: The recharge pond is to be used for return/recharge of pumped groundwater back to the alluvial aquifer, and as pumping increases the secondary recharge pond then receives pumped groundwater and returns/recharges back to the alluvial aquifer before flowing into an overflow pond that then discharges to the Poudre River. The features have also been approved by the State Engineer's Office for the attached Substitute Water Supply Plan. The features were briefly described in the original application but only one large recharge/settling pond was proposed as shown on the original mining plan, the recharge ponds were also described in Exhibit E under the Groundwater Specific Requirements, as well as in Exhibit G (referred to as settling ponds), and described in the Adequacy Review No. 1 response letter. With this technical revision the Operator is proposing to add a secondary recharge pond and an overflow pond in addition to the single recharge pond. 7. The currently approved Exhibit F — Reclamation Plan Maps (F-1 and F-2) indicate the locations of the inlet and outlet structures. The proposed Reclamation Maps (F-1 and F-2) do not show the location of the structures. Please update the revised Reclamation Plan Maps to indicate the inlet/outlet structure locations. Additional, please confirm the design for the structures remains the same as in the approved permit application. Please update the construction sequence and timing for the structures for the revised Mining and Reclamation Plans phasing. For reference in the adequacy response letter for the original application dated August 26, 2019, Item #22, the Operator stated: The operator is proposing to install the inlet/outlet spillways during mining of each phase. The spillways for Phase 1 and 2 areas will be installed as mining progresses down. Once the mining has progressed down 15 to 20 feet in Phase 1 the riverside spillways will be installed. The riverside spillway for Phase 1 will be installed first, then the riverside spillway Phase 2 will be installed(once mining occurs in Phase 2), then the pitside spillway in Phase 3 will be installed to convey floodwaters if encountered from Reservoir 1 to Reservoir 2. The pitside spillway from Reservoir 2 to Reservoir 3 will be installed once mining occurs in Phase 4. The pitside spillway from Reservoir 3 to Reservoir 4 will be installed once mining occurs in Phase 5; and the riverside spillway in Reservoir 4 will also be installed once mining occurs in Phase 5. These riverside and pit side spillways are designed per Urban Drainage and Flood Control District's Technical Review Guidelines for Gravel Mining and Water Storage Activities Within or Adjacent to 100-Year Floodplains. 4 M 305 Denver Avenue—Suite D•Fort Lupton CO 80621 •Ph: 303-857-6222•Fax: 303-857-6224