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L.G. Everist, Inc Ragsdale Reservoirs <br />M-2002-007 June 26, 2020 <br />BANK ARMORING PLAN <br />This bank protection plan is presented to explain the bank <br />armoring proposed for reservoir bank protection in Phase 1 and <br />Phase 2 that run parallel to the South Platte River channel. <br />Only the reservoir side armoring is being proposed since the <br />river bank lies 150 to 250 feet west of the top of the slope of <br />the permit area. <br />The attached Figure 1 shows the cross-section of the area <br />discussed below and details of the armoring to protect the banks <br />along the west side of Phase 1. The west and south banks in <br />Phase 2 will also be armored using this plan. The Reclamation <br />Plan Maps have been revised to show the location of the areas to <br />be armored in the mine. <br />The armor is intended to protect the reservoir banks should a <br />100-year flood event occur after an area has been reclaimed. The <br />armoring will be covered with a 6-10 inch layer of growth medium <br />and seeded with the approved seed mix. <br />The toe of the slope armoring will be at least 5 feet below the <br />thalweg of the adjacent riverbed. The base of the armoring will <br />average 10 feet below the existing ground surface at the mine. <br />The 100-year Floodplain information has been included on all of <br />the Map Exhibits in the Reclamation Packet. <br />Armoring material will be recycled concrete fragments with <br />surface rebar removed, so that it meets the definition of Inert <br />Materials. The concrete will be sized 9 to 15 inches averaging 12 <br />inches. Fines will be mixed in to fill voids. This size material <br />will have a Safety Factor of 1.26. See Bank Armoring Calculation <br />page following this text. <br />The operator will keep enough material stored on the mine to <br />complete armoring needed on any area where sloping is being <br />completed and is ready for armoring. At a minimum, 2,350 cubic <br />yards will be stockpiled on the mine for use in armoring. This <br />is enough to armor a minimum of 1,000 feet of excavation bank. <br />At no time will there be more than 1,000 feet of armoring needing <br />to be placed. <br />The stockpile of armoring material will be placed parallel to the <br />water flow so it will not interfere with flows in the flood plain <br />if flooding occurs. It will be within the setback between the <br />permit boundary and the mine highwall so it is close to the area <br />where it will be placed.