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Rifle Gravel Pit#1 June 2023 <br /> Size of Area Worked at 30% <br /> The estimated area to be mined (processed and stockpiled) at 30% is approximately 3.67 <br /> acres (depicted in Figure 9, Exhibit C4) and amounts to approximately 88,000 CY of <br /> mined (processed and stockpiled) material. <br /> Size of Area Worked at 60% <br /> The total estimated area to be mined (processed and stockpiled) at 60% is approximately <br /> 5.58 acres (depicted in Figure 10, Exhibit C5) and amounts to approximately 140,000 CY <br /> of mined (processed and stockpiled) material. <br /> • Cumulative area estimated at 60% = 5.58 acres <br /> o Estimated area mined and processed between 30% and 60% = 1.91 acres <br /> • Cumulative volume of material mined and processed at 60% = 140,000 CY <br /> o Estimated volume of material mined and processed between 30% and 60% = 52,000 <br /> CY <br /> Size of Area Worked at 100% <br /> The total estimated area to be mined (processed and stockpiled) at 100% is approximately <br /> 9.90 acres (depicted in Figure 11, Exhibit C6) and amounts to approximately 292,810 CY <br /> of mined (processed and stockpiled) material. <br /> • Cumulative area estimated at 100% = 9.90 acres <br /> o Estimated area mined and processed between 60% and 100% = 4.32 acres <br /> • Cumulative volume of material mined and processed at 100% = 292,810 CY <br /> o Estimated volume of material mined and processed between 60% and 100% _ <br /> 152,810 CY <br /> Equipment <br /> This phase will use conventional mining equipment for this phase, including but not limited <br /> to a long-reach excavator, a bulldozer, track-hoe, screening plant, wash plant, crusher, and <br /> a 35-ton haul truck. <br /> 5.2.3.1 Mining Methods and Earthmoving <br /> This phase of the project will include mining, stockpiling of material for screening, washing <br /> and crushing processes. <br /> • The working surface of the mine will consist of the alluvial gravel surface that is <br /> exposed after removal of the overburden. A long-reach excavator stationed on the <br /> edge of the pit will excavate material to a depth of approximately 20 feet. The pit will <br /> fill with water as excavation proceeds, forming a pond that expands as the excavator <br /> continues to remove material. The pond water will be in direct contact with the water <br /> table of the Colorado River via lateral migration through the underlying permeable <br /> gravels. Excavated material will be piled on the edge of the pond to allow drainage of <br /> free water from the material back into the pond. <br /> • Sideload dump trucks will travel to the pond edge and will be loaded with the dried <br /> material. The dump trucks will transport the dried material from the active excavation <br /> area to the processing facility (800 feet to1,500 feet depending upon the mining <br /> 28 <br />