2021-09-09_REVISION - M2004044 (10)

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and gravel materials, clay, silt, and other non-marketable materials excavated from the proposed permit area will be used on-site for reclamation. The mining plan currently includes mining in two phases. Mining may occur simultaneously in more than one phase. The actual sequence may change depending on market conditions, operational needs, or site conditions: • West Area (Phase 1), is located north of Highway 7 and west of Tucson Street and included Tracts A, B and C • East Area (Phase 2) is north of Highway 7 and east of Tucson Street and includes Tracts D, E, F, G and H Tracts N, O, P, Q, R, and S will contain the conveyor to export product off-site to the Wattenberg Lakes Site and will be used during all mining phases. Mining will begin in the West Area (Phase 1). Once mining is complete in the West Area, mining will commence in the East Area (Phase 2). All necessary permits will be obtained. A summary of mining phases is presented in the table below. Processing and sale of the material will occur on the Platte Valley site (M-1989- 120). Overburden from the West and East Areas will be used to reclaim the cells. If there is excess overburden material, the material will be conveyed to the Platte Valley site and Wattenberg Lakes site for reclamation. A slurry wall will be constructed around the East and West Areas prior to exposure of the water table. The slurry wall has been designed and is attached to this exhibit. Mine Phasing Summary Mine Phase Total Duration Acreage To be ears West 72.0 4 East 83.8 4 Tot 155.8 8 Mining Methods The method of mining used within the permit boundary: • The slurry wall liner for the West and East Areas will be installed prior to exposure of ground water at the site. Once the slurry wall is installed the West and East Areas will be dewatered. The deposit will be dry mined using dewatering trenches and pumps within the slurry lined area. Prior to excavation of each mining phase, trenches will be cut along the perimeter of the excavation to begin dewatering the sand and gravel material. The trenches will extend through the overburden and alluvium to bedrock. Pumps will be used to remove the groundwater that drains from the deposit within the lined excavation. If necessary, water from the trenches will be circulated through a settling pond prior to being discharged to adjacent drainage ditches and/or the Aggregate Industries—Tucson South Amendment—MLRB 112 Permit Application Exhibit D-4