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• <br />ROCKY MOUNTAIN CONSULTANTS, INC. <br />November 13, 2000 <br />Mr. Jeff Gregg <br />Hall-Irwin Corporation <br />P.O. Box ~ 19 <br />Greeley, Colorado 80632 <br />• iii iiiiiiiiiiiii iii <br />Inc <br />Premiere Building <br />825 Delaware Ave.. Suite 500 <br />Longmont, CO 80501 <br />(303) 772-5282 <br />Metro (303) 665-6283 <br />FAX (303) 665-6959 <br />(firs} initial, last name)@long.rmcco.com <br />Re: Hall-Irwin Corporation, La Poudre North Aggregate Mine, MLRB 112; <br />RMC Job No. 80-0636.056.00 <br />Dear Mr. Gregg: <br />This letter has been prepared to address Construction Materials Rule 6, Section 4, Subsection 19, <br />Exhibit S -Permanent Man-Made Structures (6.4.19, Exhibit S) for the above-referenced proposed <br />aggregate mine. <br />The proposed mine will occupy approximately 37.8 acres (Lot B) of the Roth property located in <br />parts of the northeast quarter of the northwest quarter and the northwest quarter of the northeast <br />quarter or Section 19, Township 6 North; Range 67 West of the 6th Principal Meridian in Weld <br />County, Colorado. The site is immediately south of State Highway 392 and approximately 1,170 <br />feet east of ~~'eld County Road 13. The Cache la Poudre River is approximately one-quarter mile <br />south of the site. Land use in the area is mostly agricultural and rural residential with newer <br />encroaching residential and commercial developments. Several sand and gravel mines are also <br />present in the alluvium along the Cache la Poudre River. <br />Plans are to mine the site in two pods. The first pod will encompass 17 acres on the east part of the <br />property, and the second pod will consist of 16 acres on the west part of the property. Mining in <br />each pod will progress in three steps. In Step 1, topsoil and overburden will be stripped and <br />stockpiled in separate piles approximately 10 and 20 feet wide, respectively, around the perimeter <br />of the mine disturbed area. In Step 2, an approximately 75-foot wide zone of aggregate will be <br />mined just inside the perimeter of the mine excavation area. Step 2 mining will consist of <br />progressively dewatering (with a perimeter trench and pump) and mining the aggregate in <br />progressively deeper layers, resulting in a near vertical face on the perimeter of the mine <br />excavation. In Step 3, the dewatering trench will be relocated more toward the pod interior <br />allowing room for the excavation perimeter to be reclaimed at 3:1 slopes (horizontal to vertical) <br />utilizing the stockpiled overburden and topsoil. Mining of the pod interior would then progress. <br />Upon completion of the mining, each pod will be reclaimed as a pond. <br />GEOLOGIC STRATA <br />The mine site is located on a terrace of the Cache la Poudre River. Review of regional geologic <br />mapping (Colton, 1978) indicates the site subsurface materials consist of Post-Piney Creek Alluvium <br />CIVIL AND ENVIRONMENTAL ENGINEERING PLANNING <br />