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Dowe Flats Special Use Permit Amendment Application May 2, 2022 <br /> The extension would allow for the extraction of limestone and shale (sedimentary rocks that are <br /> composed of minerals), a finite resource that is necessary to meet a societal need(the need for <br /> cement to make concrete). Because continued extraction of this finite resource would occur <br /> within the confines of the currently permitted disturbance boundary, no additional land will be <br /> disturbed. Reclaiming the site before all mineral resources have been extracted would mean <br /> leaving behind a valuable resource, which would diminish its efficient use. <br /> In addition, the Dowe Flats operation is very energy efficient because all material from the site is <br /> processed and then sent straight to CEMEX, Inc.'s cement plant via a covered, electric <br /> conveyor. No haul trucks are used to transport the material from Dowe Flats to the cement <br /> plant. However, if Dowe Flats is no longer able to supply CEMEX, Inc. with its mineral <br /> resources, the material will need to come from another source which likely would require the <br /> use of trucks to haul it to the cement plant. <br /> Finally, continued mining at Dowe Flats is economically responsible and in the best interests of <br /> the County and its residents. Allowing for the extraction of the material from Dowe Flats, an <br /> existing facility that is essentially adjacent to the cement plant where it is utilized minimizes raw <br /> material and transportation costs. The costs associated with mining and transporting the <br /> material from Dowe Flats to make cement figures into the cost of the cement used to make <br /> concrete and impacts consumers in both the private and public sectors. <br /> 12. The use will not result in unreasonable risk of harm to people or property- both onsite <br /> and in the surrounding area -from natural hazards. Development or activity associated <br /> with the use must avoid natural hazards, including those on the subject property and <br /> those originating off-site with a reasonable likelihood of affecting the subject property. <br /> Natural hazards include, without limitation, expansive soils or claystone, subsiding soils, <br /> soil creep areas, or questionable soils where the safe-sustaining power of the soils is in <br /> doubt; landslides, mudslides, mudfalls, debris fans, unstable slopes, and rockfalls; flash <br /> flooding corridors, alluvial fans, floodways, floodplains, and flood-prone areas; and <br /> avalanche corridors; all as identified in the Comprehensive Plan Geologic Hazard and <br /> Constraint Areas Map or through the Special Review process using the best available <br /> information. Best available information includes, without limitation, updated topographic <br /> or geologic data, Colorado Geologic Survey landslide, earth/debris flow data, interim <br /> floodplain mapping data, and creek planning studies. <br /> The Dowe Flats quarry has been in operation for over 20 years and there have been no <br /> unreasonable risks to people or property on or around Dowe Flats due to quarry activities. The <br /> Colorado Division of Reclamation Mining and Safety(DRMS) ensures that mining activities will <br /> not impact the structural integrity of any existing structures within 200 feet of the high wall of a <br /> mine. The closest neighboring structure to the high wall at Dowe Flats is a building associated <br /> with the City of Longmont's water management facility, and it is over 4,500 feet away. Mining at <br /> Dowe Flats has never posed a risk to any neighboring structure and continuing to mine the site <br /> will not change that analysis because the location of the mining cell will remain within the <br /> permitted disturbance boundary. <br /> In addition, the design of the Dowe Flats quarry considered the geology of the site from the very <br /> beginning to ensure that no safety hazards would be created inside the mine. The DRMS <br /> reviewed the design when the mine was originally permitted, and they concurred. Since <br /> CEMEX, Inc. first began operating, there is no record of any natural hazards creating problems <br /> at Dowe Flats. The rock in the quarry dips an average of about 15 to 20 degrees to the east and <br /> all highwalls are developed on the up-slope side of these rock beds so that the dip is always <br /> sloping away. The competent nature of the mineral resources and the beds dipping away, and <br /> the highwall being constructed perpendicularly to the dipping of the material, assure safe <br /> Review Criteria Statement- Page 10 O TETRA TECH <br />