2021-02-03_REVISION - M2020008 (4)

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Rifle Gravel Pit #1 January 2021 (Amendment to File No, M-2020-008) 5.2.2.3 Schedule of Operations The Rifle Gravel Pit will operate from 7 am to 7 pm Monday through Friday, and weekends, as needed. SCI will limit winter operation hours between the hours of 7 a.m. and 5 p.m. Approximately 3 to 5 employees will be on site during this phase of the mining operations. No nighttime activities are anticipated. Occasional equipment repair, or maintenance may be conducted at night, but lighting will be kept to a minimum and directed inward; the site will not have ambient lighting. 5.2.2.4 Explosives Explosives will not be used during mining or reclamation of the property. 5.2.3 Mining Extraction (Phase 3— in 5 Stages) Mining extraction operations will take place in 5 extraction stages. Stage 1 of the mining extraction operation will start in the southeastern quadrant of the site. At this location, the crusher will be placed at the current grade and mining the mineral out to the lowest elevation of the gravel. Once this area is mined out, the crusher will be set on the floor of the pit for Stage 2 of the mining extraction operation. Stage 2 will take place in the northeastern quadrant of the property following Stages will proceed in a counterclockwise rotation around the property (Figure 9, Exhibit D). The location of the mining equipment in the bottom of the pit will support mitigation of the mining noise and dust. All stockpiling of material at this point also be done at this level. Each following stage (3 through 5) will follow this method throughout the mining extraction process at this site. 5.2.3.1 Stockpiling and Overburden Handling This phase of the project will include stockpiling of material for screening, washing and crushing processes. Figure 9 depicts the approximate locations of these stockpiles during each stage. Equipment for this phase will include, but not be limited to, a bulldozer, track- hoe, and a 35-ton haul truck. 5.2.3.2 Water Handling and Dewatering Phase 1 dewatering activities will continue throughout this phase. Any water encountered at the bottom of the pit during this phase will be intercepted by a buried perforated pipe (estimated at three feet below the mining floor). It is assumed that any water captured in the perforated pipe will be pumped by the dewatering well. SCI will comply with the State Engineer Office's (SEO) rules and regulations regarding any water depletions that may also occur during mining operations from water lost with mined aggregate and water used for dust suppression. 5.2.3.3 Schedule of Operations The Rifle Gravel Pit will operate from 7 am to 7 pm Monday through Friday, and occasional weekends, as needed. SCI will limit winter operation hours between the hours of 7 a.m. and 5 p.m. Approximately 5 employees will be on site during this phase of the mining operations. No nighttime activities are anticipated. Occasional equipment repair, or maintenance may 20