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EXHIBIT D - Mining Plan <br /> a) Description of Methods:The area will be stripped so that the crushing and screen plants can be set up on the <br /> west end of the permitted area.Topsoil thicknesses at the Koskie site are thin,typically less than 12(twelve) <br /> inches. Topsoil will be stockpiled mainly on the western perimeter of the mining area and will be seeded to <br /> prevent erosion and loss of soil. Some stockpiling may occur on the eastern perimeter of the mining area and <br /> previous stockpiling has occurred on the northern perimeter as well.Please see Exhibit C3 for depiction of the <br /> topsoil stockpile areas. Mining will start on the east end of the permitted area and progress to the west, <br /> generally moving north to south. It is anticipated that mining will be done using excavators,front end loaders, <br /> dozers, scrapers, and haul trucks. Best Management Practices, including berms, silt fencing, and straw bales <br /> erosion control measures will be installed along the east end of the Koskie site to protect the adjacent <br /> intermittent creek area from mined area runoff and sediment. Open excavations are not anticipated to be over <br /> 15 feet deep,MSHA approved open excavation and fall protection safety measures including fencing and berms <br /> will be installed as needed. During and following mining,side slopes to the pit will be graded for stability and <br /> will be re-vegetated as needed to meet the reclamation plan. <br /> b) Earthmoving:Excavation and stockpiling volumes are anticipated to be approximately 100,000 to 150,000 tons <br /> per year. <br /> c) Water Diversions and Impoundments:The Koskie property is located approximately l/z mile west of Lone Tree <br /> Creek which is an intermittent stream that is typically dry most months of the year. There are no irrigation <br /> structures, surface water impoundments, or water diversions existing or anticipated at the site. Test pitting <br /> performed at the Koskie site shows that groundwater is deeper than approximately 15 feet.Mining is proposed <br /> to stay at least two feet above groundwater.Because of this,dewatering is not proposed.The CDPHE permit <br /> will be a`stormwater only'permit.Alluvium materials similar to the material being mined are located beneath <br /> the material to be mined. The water table is greater than 2 feet below the level to which Weld County will <br /> mine. To prevent the exposure of ground water, Weld County will not mine the alluvium materials located <br /> beneath the material to be mined. Additionally,the deepest excavation will be slightly higher than the bench <br /> terrace located directly east of and adjacent to the site.This will assist in avoiding exposure of groundwater and <br /> facilitation of surface water drainage out of the pit. According to information obtained from the State <br /> Engineer's Office,the Koskie site is not located within a designated groundwater basin. <br /> There is one well that is used for stock watering within 200 feet of the mine permit area. Water needs for <br /> gravel mining and processing operations are expected to minimal;water for dust control can be obtained and <br /> hauled from existing County-owned wells that have been decreed for the appropriate uses. Water from the <br /> nearby well will not be used for any County operations. Water used in mining and crushing operations and for <br /> dust control is estimated to not exceed approximately 4000 gallons per month during those operations. <br /> d) Size of areas to be worked:The enclosed mine plan map(Exhibit C3)shows the proposed locations for the haul <br /> road,gravel processing(crusher location),soil and gravel product stockpile areas.The application proposes a <br /> mining area of 122.9 acres.Of this mining area,about 77.75 acres will be mined.The remaining acreage may <br /> be used for topsoil stockpiling or will be left unmined.All topsoil in the amended mining area will be stripped, <br /> stockpiled,and stabilized at one time.Once mining begins,approximately 20-25 acres will be exposed at any <br /> one time. <br /> e) It is anticipated that sand and gravel excavation,processing(rock crushing and screening),and stockpiling at <br /> the Koskie site will commence upon receipt of approval from the Colorado Division of Reclamation, Mining <br /> and Safety(DBMS)and receipt of other necessary permits. Gravel excavation and processing will be seasonal <br /> with stockpiling of gravel for later County uses depending upon the local road repair and construction needs. <br /> While gravel excavation and processing are expected to be seasonal,it is anticipated that the material stockpiles <br /> will be hauled out of the site year-round. The Koskie site should not be considered an intermittent operation. <br /> i. The mining operation in the amendment area is not proposed to be phased. The Koskie amendment <br /> C\Users\hbalzano\Desktop\Koskie\Koskie Amendment Application Exhibits 04-29-20 doc <br /> 4/29/2020 <br />