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Exhibit D-Mining Plan Topsoil in Expansion Area North is minimal due to historic sand and gravel mining activities. Most topsoil was previously stripped and no longer exists onsite. Topsoil materials will be salvaged separately from subsoil materials if present. Based on site investigation and test pits, the salvage depths at Expansion Area North are less than 1.0 foot. Topsoil and subsoil removal and replacement operations may be conducted with any of several combinations of mobile equipment including scraper, truck/shovel, truck/loader, backhoe, dozer, etc. Any salvageable topsoil and subsoil, will be relocated to the existing topsoil storage area on the Worthing Pit property. Sand and gravel excavation will start only after topsoil salvage is completed. If topsoil stockpiles are left undisturbed for more than one year, a cover crop of Western wheatgrass will be planted on the stockpiles at a minimum rate of 3 pounds of pure live seed per 100 square feet. Approximately 35,000 cubic yards of topsoil is stored within the stockpiles at the Worthing Pit. Not all this stockpiled topsoil will be required for reclamation of the existing permitted mine because the ponds will not require revegetation except for the shorelines. Excess topsoil from Worthing Pit may be used for revegetation at Expansion Area North. The maximum thickness of the sand and grave] unit in Expansion Area North is approximately 12 feet, with the actual thickness variable due to depositional character, quality, previous mining activities and erosion. This material will be stockpiled in the Worthing Pit storage area until processed and sold. Mining activities will be conducted with one shifr per day based on a ]0-hour shift and asix-day workweek. Surface mining operations will be limited to 10 hours per day between 6:OOam and 9:OOpm (maintenance activities may occur at any time). Mining operations will use standard methods and equipment commonly used in sand and gravel removal operations. Mobile equipment, such as (or the equivalent of) Komatsu PC400 excavator and Volvo A30 30-ton haul trucks will be used. The excavated sand and gravel will be crushed, screened, washed and stockpiled. All sand and gravel recovery activities in Expansion Area North will be completed within one to three years. Sand and gravel will be removed via excavator, loaded into a haul truck and transported to the Worthing Pit stockpile area. A total of approximately 550,000 tons of sand and gravel will be mined from Expansion Area North. Maximum depth of the pit will be approximately 24 feet at the south end. Existing on-site erosion and sedimentation control structures will be used for the Expansion Area North. Any storm water or ground water entering the disturbed area will be pumped into the settling basin and allowed to settle prior to off-site discharge using existing facilities. All discharged water will conform to the existing Colorado Discharge Permit System (CDPS) Permit No. COG-500233. In cooperation with several local water districts, UDFCD prepared the Major Drainageway Planning South Platte River in Adams County, Colorado, Phase B Report (Drainageway Plan) (CDM 2002). As part of the Drainageway Plan, the east bank of The South Platte River adjacent to Expansion Area North will be stabilized (Exhibit C-2). This bank stabilization will be designed and constructed under the supervision of UDFCD and will further develop their long-term plan for the South Platte River. The armored bank will be constructed before mining commences within the defined 100-year floodplain. Prior to installation of the bank stabilization, no mining activities will be conducted closer than 400 feet from the top of bank of the South Platte River. Following installation of the bank stabilization, mining activities will be conducted no closer than 100 feet from the armored and stabilized bank crest without UDFCD approval. 1898-Frei ] 12 Exhibits_(4.2Q05).doc D-4