Laserfiche WebLink
CIVIL RES''suRCES, LLC <br /> ENGINEERS & PLANNERS <br /> January 30,2019 <br /> Colorado Division of Reclamation and Mining Safety <br /> Mr. Peter Hays <br /> 1313 Sherman Street, Room 215 <br /> Denver,CO 80203 <br /> RE: Technical Revision 7-S&H Mine(Permit M-2000-158),Weld County, Colorado <br /> Dear Mr. Hays: <br /> Scout Investments requests a Technical Revision 7(TR-07)to Permit M-2000-158 to allow modification of the reclaimed <br /> storage configuration at the S&H Mine. A site location map is provided on Figure 1. <br /> Background <br /> The property associated with the DRMS mining permit M-200-158(commonly S&H Mine)was subdivided and sold to two <br /> entities. The north parcel of the S&H Mine was sold to Scout Investments and the south parcel of the mine was <br /> purchased by the City of Aurora (Aurora). Scout Investments retained sole ownership of the DRMS mining permit M- <br /> 2000-158 over both parcels as part of that sale. <br /> The current approved reclamation plan was outlined in Amendment 2 approved in February 2011. This plan consists of <br /> six (6) reservoirs referred to as Cells A, B, Cl, C2, D1, and D2. Water storage in these reservoirs would have been <br /> achieved by a combination of slurry wall lining the below grade excavation (mining) and the placement of earthen fill in <br /> above grade dams which were approved by the Dam Safety Branch of the State Engineer's Office(SEO). The maximum <br /> height of fill in this approved reclamation plan would have been approximately 36 feet above existing grade. To date,an <br /> at grade slurry wall has been constructed in the area of Cell Cl and a small area within the slurry wall has been partially <br /> mined. <br /> Proposed Revisions to the Mining and Reclamation Plans <br /> This Technical Revision 7(TR-07)proposes two revisions: <br /> - Cell C2: The approved reclamation plan includes Cells Cl and C2 which both include significant above grade <br /> berming and water storage. TR-07 maintains the existing "Sharkey Pit" slurry wall and removes the berming <br /> and previously proposed above grade storage for Cell Cl and C2. Compacted earthen fill will be placed along <br /> the perimeter of the proposed C2 to provide a flat construction bench necessary to construct the slurry wall <br /> outside of the defined floodway along the same alignment as the fill limits approved in Amendment 2 (SEO). <br /> The fill will average approximately two (2) feet. As was the case in Amendment 2, the below grade water <br /> storage will be accomplished by lining the mined cells with a soil-bentonite slurry wall tying into the existing <br /> Sharkey Pit(C1)slurry wall. <br /> - North Silt Pond: Adds a silt pond location near the northeast corner of the Site. This area will be mined and <br /> reclaimed by backfilling it to existing grades. Evaporative and other depletions will be considered in the TSSP <br /> associated with the project and approved by the SEO. Final reclamation of the area will include backfill with silt <br /> fines from aggregate production and other uneconomical material such as overburden or mud lens within the <br /> alluvial deposit. Six inches of topsoil will be placed over the top of the backfill. The topsoil will be drill seeded <br /> using the site approved seed mix summarized in the table below. Similarly,top soil and the same seed mix will <br /> be utilized to revegetate disturbed areas of the mine that will not be open water. <br /> 323 FIFTH STREET• FREDERICK,COLORADO 80530• PHONE:303.833.1416• FAX:303.833.2850 <br />