2018-11-02_PERMIT FILE - M2018037 (2)

Home Browse Search

CMI RFS 15)URCFS, Iti RECEIVED October 31, 2018 1^w 0 1 2018 WELD COUNTY Mr. Eric Scott COMMISSIONERS Division of Reclamation, Mines, and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 RE: Adequacy Review 1 for 112 Construction Materials Reclamation Permit Application Package, Inouye Gravel Mine, Permit M-2018-037; Response Dear Mr. Scott: This letter is being generated to satisfy the preliminary review dated October 11, 2018 for the Inouye Gravel Mine. The italicized items are the current comment and the bold text are the responses: EXHIBIT D-Mining Plan(Rule 6,4.4): Please show the proposed location(s)of the processing area and any associated concrete and asphalt plants that will be located on-site. The concrete and asphalt plants will be located in the northwest corner of the site outside of the floodway. The processing area is going to be located on the west side of the site. The attached plans show the location of processing area and the plants shaded in grey. It should also be noted that a slight adjustment in the permit boundary changed the permitted acreage to 120.0 acres. The mining plan provided states that phases will be mined at 0 51+I V slopes Please specify the maximum linear feet of"working face"that will require re-sloping to.7. 1 at any time, average depth of excavation, an estimate of how many cubic yards of overburden will be required to reconstruct the slopes to 3.1, and show locations of overburden and topsoil stockpiles on the mining plan Please keep in mind that haul distance, and amount of cubic yards required to re-construct 3:7 slopes will have a significant impact on reclamation costs. Also note that topsoil and overburden stockpile locations may be restricted due to the floodway concerns. The tables below show the necessary quantiles and timeframes required to mine, based on a production rate of 500,000 tons per year(market dependent). Mining Phase Gravel Overburden Time (tons) (tons) (Yrs) 1 1,200,000 148,000 2.4 2a 1,900,000 244,000 3.8 2b 1,600,000 197,000 3.2 3 1,700,000 242,000 3.4 Total 6,400,000 831,000 12.8 After further review the miner has changed mining phases 2a, 2b and 3 to be mined at 3 horizontal to 1 vertical. The change does not affect the reclamation as the proposed finished below grade reservoirs were to be reclaimed at 3 horizontal to 1 vertical. The drawings have all been updated. The reasoning for this is the shortage of onsite material to backfill the slopes and future use of the