2019-08-29_PERMIT FILE - M2019028 (3)

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RE: J-2 Contracting Company—DPG Pit—Permit No. M-2019-028 112(c)Permit Application Adequacy Review No. 1 Response 8126119 -7- 26) The reclamation plan maps submitted in Exhibit F show four different types of riprap lined spillways (A-D) proposed to be installed on the reservoirs for reclamation. Please provide details on these proposed structures in Exhibit E, including an explanation for the different types, number, and locations proposed. The operator could always revise the proposed inlet/outlet structures at a later date through submittal of a Technical Revision, once the operational criteria for the reservoirs have been identified. However, the Division must hold bond costs for installing the proposed inlet/outlet structures, at a minimum, on the reservoir(s) to be mined within the proposed maximum disturbance scenario. Therefore, sufficient details for these structures must be provided to calculate the required financial warranty. Response: The design information for the spillways has been included in the attached information. The spillways were designed per the Urban Drainage and Flood Control District's Technical Review Guidelines for Gravel Mining and Water Storage Activities Within or Adjacent to 100-Year Floodplains. Details of the proposed spillways have been provided with the Exhibit F reclamation plans and updates to the Exhibit L bond calculations have been provided for the spillway construction cost for each phase of mining. 27) Please provide more details on reclamation of any recharge pond areas and sediment control structures, including the approximate volume of backfill material required. Additionally, please be sure any costs for reclaiming these features are included in the Exhibit_L bond estimate. Response: The recharge pond area is already an existing feature so the reclamation cost for the recharge pond will only be re-seeding this area. The re-seeding cost has been provided in the revised Exhibit L bond calculations. The sediment ponds are above grade and will require removal of the berms and sediment within the ponds and costs are included in the revised Exhibit L bond calculations. 28) Please provide details on reclamation of the dewatering pipe shown on the Exhibit C-4 — Mining Plan Map. Additionally, please be sure any costs for reclaiming this feature are included in the Exhibit L bond estimate. Response: The dewatering pipe is going to be lay flat hose so it will not be buried. The overflow pipe from the recharge pond to the river will be buried and costs to reclaim the pipe have been included in the revised Exhibit L bond calculations. 29) Please provide details on reclamation of the proposed aggregate processing plant and concrete and asphalt batch plant. Will any structures (e.g., concrete foundations, buildings) require demolition for reclamation? Please be sure any costs for reclaiming these features are included in the Exhibit L bond estimate. Response: The aggregate processing plant, asphalt batch plant, and concrete batch plant are all portable so there are not any concrete foundations proposed for these facilities. There will not be any reclamation needed for the structures other than re- seeding these areas if the mining stops. If mining continues the areas where the plants would be located eventually get mined out. 30) Please provide details on reclamation of the proposed truck scale and scale house. Will any structures (e.g., concrete foundations, buildings) require demolition for reclamation? Please be sure any costs for reclaiming these features are included in the Exhibit L bond estimate. Response: The scale and scale house foundations will require demolition for the 4r, 305 Denver Avenue—Suite D•Fort Lupton CO 80621 •Ph: 303-857-6222•Fax:303-857-6224