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<br /> <br />Portland Limestone Quarries (M-1977-344) Permit Amendment-02 <br />Holcim US Inc, 3500 Highway 120, Florence, CO 81226 Revised pursuant to preliminary adequacy review November 20, 2023 <br />Phone (719) 288-1443 www.holcim.us 73 <br />The conveyor system and conveyor service road will be enclosed by a 6-foot-high chain link fence to <br />prevent wildlife from coming in contact with the moving conveyor. The fence will end as the conveyor <br />begins to elevate for the wildlife crossings and recommence as the conveyor elevation drops to within 6 <br />feet of the ground surface. The fence will have security gates on each end of the overland stretches of <br />conveyor. <br />2.4.4.2 Red Creek Quarry Infrastructure Development <br />RCQ development will include building a shop/office building, installing a sanitation vault, grading areas for <br />equipment and vehicle storage and an area for the secondary crusher in the northwest corner of Section <br />24. The area will be prepared by drilling, blasting and excavating material from a 1,000 feet by 800 feet <br />area using a bulldozer, a loader and off-road haul trucks. <br />The quarry shop and offices will be located in a 184-foot by 70-foot metal building constructed on a <br />concrete slab (Figures 2.4.4.2-1 thru 5). The concrete slab will be reinforced with rebar and will be 8 <br />inches thick in the warehouse, 4 inches thick in the office and 12 inches thick in the shop. The shop <br />building will have electricity from the area provider, a septic vault engineered for up to 25 employees and a <br />water well for sanitation and equipment maintenance needs. Equipment will be maintained and repaired in <br />the shop. The shop will include wash bays and floor drains that discharge into an oil/water separator. <br />Diesel fuel will be stored on site in a 20,000-gallon double walled above ground fuel tank with concrete <br />wall crash protection structure. <br />2.4.5 Mine Development <br />Mining will occur as a conventional open pit mine utilizing drilling, blasting, loading, and hauling <br />equipment. Limestone for the plant will be transported from the blasted working faces by excavators to <br />potentially two in-pit mobile crushers located in the vicinity of the working face. This initial crushing will <br />produce 8-inch minus material. The 8-inch minus material will be conveyed to the secondary crusher in the <br />northwest corner of Section 24. The secondary crusher will reduce the feedstock to 4-inch minus +/- 0.5 <br />inch that will be transported by conveyor approximately 5.7 miles to the blending hall for further <br />processing. <br />Plant growth material will be salvaged and stockpiled during all site development and mining activities. Up <br />to two feet of plant growth material will be ripped and pushed into a temporary stockpile. Haul trucks will <br />transport the material to the property boundary and planned quarry area for construction of a 10-foot-high <br />perimeter berm. In the event plant growth material will not be used in reclamation within one year, it will be <br />seeded with a temporary seed mix to stabilize the surface until the material is needed in final reclamation. <br />During initial mine development, a temporary stockpile will be located in the northwest corner of Section <br />24 (Figure 2.4.5-1). The temporary stockpiles will be 1,200 feet by 800 feet with a total capacity of 3.1M <br />tons. It will be constructed in separate stockpiles of overburden and limestone. Once sufficient mine floor <br />is mined out, the overburden stockpile material will be pushed into the quarry as backfill for slopes. The <br />anticipated life of the temporary stockpiles is less than 20 years. <br />The limestone mine will develop as a surface mine with benches and a perimeter berm (Figure 2.4.5 -2). <br />Limestone will be mined by cutting benches with a vertical face of 36 feet and a bench of 20 feet. The <br />depth of limestone is approximately 140 feet deep with Codell sandstone below the limestone deposit. The <br />crest of the mine bench will be 150 to 200 feet within the permit boundary. A 10-foot berm will be <br />constructed of overburden approximately 100 feet from the crest of the limestone bench. <br />The sandstone mine will be an open pit mine in the floor of the limestone mine. After extracting the <br />limestone, a sandstone pit will be developed in the Codell. Sandstone will be mined from two 23-acre <br />locations along the west boundary; one in each Section. Sandstone will be mined to a depth of 15 feet as <br />a typical open pit mine using backhoes and haul trucks. The slopes of the sandstone pit will be 3H:1V.