2024-04-25_PERMIT FILE - M2024017

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EXHIBIT D MINING PLAN 1 . General Mining Plan The property boundary has been surveyed on site and the permit area will be surveyed prior to any site disturbance. Map C-2 shows the mining plan. Mine access will be via the existing Brig gravel pit and will use its access to public roads. Internal haul roads will facilitate access to all mining areas. Mining of the Lockhart Pit will involve roughly 114 acres of total affected area. The primary commodity to be mined is sand and gravel for use in construction materials such as crushed rock, sand, washed rock, concrete, and asphalt. Fill dirt may be incidentally produced during the operation. The top 12 inches of material onsite is assumed to be topsoil. The underlying alluvial sand and gravel deposit ranges from 20 to 30 feet with an average thickness of 25 feet. Bedrock is encountered at an average depth of 25 feet from the top of the natural grade. Topsoil and overburden will be stripped via dozer, scraper, or other earthmoving equipment prior to mining. These materials will be stockpiled separately on site to be used in reclamation. Any stockpile to be left in place longer than 90 days will be vegetated to prevent erosion. When possible, stripped topsoil and/or overburden will be directly placed on areas being reclaimed. Refer to Map C-2 for stockpile areas. The operation is mining Pleistocene terrace alluvium that lays atop the Troublesome formation. Mining will be to a depth of 20-ft. The sand and gravel deposit will be extracted using loaders, excavators, dozers, and haul trucks. Mined material will be hauled from the active pit to the Brig Pit at the east of the site. An internal haul road will be constructed to facilitate the transport of materials. Processing of the sand and gravel includes screening, washing, crushing, and the production of concrete and asphalt. All final mining slopes will be at a maximum 2H:1V slope where mining does not daylight. The final mining slopes will be at the outermost extents of the mining areas as shown on Map C-2. The active mining highwall will be mined at a near vertical slope until the halfway point of the toe and crest of the final mining slope. This allows for the remaining in-situ highwall material to be knocked down by dozer to create the final 2H:1 V slopes. the mining slopes at 2H:1 V will then be backfilled to a 3H:1V slope for reclamation (Figure D-1). No more than 1000 feet of highwall at slopes steeper than 3H:1V will exist at any point in time of mining. At a minimum, slopes will be regraded to 3H:1V if they are not within the 1000 feet being actively mined. Refer to Maps C-2, C-3, and F-1 for the final slope configurations and cross sections. Lockhart Pit March 2024 D-1 1111 Lewicki 8t Associates