2018-10-30_PERMIT FILE - M2018037

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Page 2 Mr. Eric Scott October 30, 2018 overburden material. The mine highwall has not changed and a memo is attached discussing the adequate safety of the slopes. The miner understands that the floodway limits the available stockpile area and has shown on the mining plan an approximate area for stockpiling and plans to install/place all facilities out of the floodway as well. There is approximately 300,000 tons of available stockpile area out of the floodway which can account for one mining phase at a time. The miner will have to concurrently reclaim each phase as they go. The mining plan also states that water requirements for the site will'likely"be provided by existing water rights associated with the property. Please demonstrate that the existing water rights for this property would be approved for use in this manner.Also please include available information on the existing well located in the far SW corner of the site(near MW5)and include it on the existing conditions map(sheet 2)provided. The miner intends to use existing production wells or open water for washing and concrete batching. All sources of depletions(evaporation,washing, etc.)will be included in a State approved Substitute Water Supply Plan (SWSP)covered by available augmentation sources. The miner owns various sources of replacement water located along the South Platte River, including but not limited to, a long term lease with the City of Aurora for 49.5 acre-feet per year,ongoing water leases with Central Colorado Water Conservancy District,two state approved augmentation ponds located on their Shores Gravel Mine site and their Lupton Meadows Gravel Mine Site.The existing well is shown on the attached drawings. The well is owned by the miner and in the event it is used in production it will be included in the SWSP. EXHIBIT E-Reclamation Plan(Rule 6.4.5): Seeding-specify types, mixtures, quantities, and expected time(s)of seeding and planting. The reclamation seed mix and plans for revegetation have not been provided. Please address. The seed mix is shown on the reclamation plan drawings. Please remove the reference to Bestway Concrete in the last sentence of the weed control plan. The reference has been removed. The post mining land use for the majority of this permit is developed water storage(lined reservoirs). Because the proposed reservoirs are all or partly within the Platte River floodway, the permittee will be required to provide an engineered design for spillway(inlet/outlet)structures to be incorporated into the reclamation plan to protect the integrity of the reservoirs during flood events. The flood control structures will also need to be shown on the Reclamation Plan Map. The spillways are shown on the plan and a cross section sheet has been added as well. The spillway cost is included in the bonding calculation. EXHIBITG- Water Information(Rule 6.4.7): Please commit to providing DRMS with at least 5 quarters(15 months)of groundwater level data from the 5 existing monitoring wells to determine baseline maximum and minimum pre-mining water table elevations before initiating work on-site that will impact groundwater levels in the area(installation of slurry walls, dewatering etc). This baseline data will evaluated in the event that groundwater level mitigation is required. The groundwater monitoring and mitigation plan as submitted states that if trigger levels within the existing wells are exceeded(excess of 2ft deviation from historic background levels), or if a complaint of off-site impact is received, the permittee will take action and notify DRMS within 30 days.