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• iii iiii~~iiiiiiiiii • <br /> <br />LT <br />NTS <br />INC ~~~ <br />ROCKY MOUNTAIN CONSU <br />A <br />, <br />. <br /> Premiere Building <br /> 825 Delaware Ave.. Suite 500 <br /> Longmont, CO 80501 <br /> (303) 772-5282 <br /> Metro (303) 665-6283 <br />REC FAX (303) 665-6959 <br />EIV <br />January 4, 2001 CIiG ~p (first initial, last name)®long.rmcco.com <br />OCT 2 3 2001 <br />Ms. Connie Davis DiuisionofMineralsandGeolagy <br />Aggregate Industries <br />West Cent~al Region <br />P.O. Box .121 <br />361 71 st P.venue <br />Greeley, Colorado 80634 <br />Re: Stability Analysis for Adjacent Permanent Man-Made Structures Near the <br />Proposed Aggregate Industries Mine, Peschel Property, Weld County, Colorado; <br />RAC job No. 19-3919.004.00 <br />Dear Ms. Davis: <br />This letter has been prepared to address Construction Materials Rule 6, Section 4, Subsection 19, Exhibit <br />5 -Permanent Man-Made Structures (6.4.19, Exhibit S) for the proposed aggregate mine to be located on <br />the Peschel property in Weld County, east of Longmont, Colorado. <br />The proposed aggregate mine will occupy most of the southwest quarter of Section 7, Township 2 <br />North, Range 68 West. The site is immediately east of County Line Road and south of St. Vrain Creek. <br />Land use in the area is predominantly irrigated agricultural and rural residential. Several sand and <br />gravel mines are also present in the alluvium along St. Vrain Creek. <br />Plans are to mine the site in three separate pits. The pits will be setback a minimum of 25 feet from <br />property lines. Topsoil and overburden stripped from the site will be stockpiled on the south part of the <br />site and within the 25-foot property line setback. The pits will be actively dewatered, and perimeter <br />mine headwalls will slope 0.5:1 (horizontal to vertical). Aker mining, the pits will be reclaimed with <br />side slopes no steeper than 3:1 (horizontal to vertical). <br />S/TE GEOLOGY <br />We performed an engineering geologic reconnaissance of the site on December 28, 2000. Most of the <br />site is currently irrigated corn crop land and grass land. A gravel pond and abandoned railroad grade <br />are located on the north part of the site. The Peschel residence is on the east part of the site. A <br />driveway crosses the site in an east-west orientation providing access to the Peschel house. An older <br />house and related buildings are located on the west part of the site, and will be removed before mining. <br />Dry Creek crosses the south part of the site in a generally northeasterly orientation. The confluence <br />between Dry Creek and St. Vrain Creek is immediately east of the site. <br />The site s located in the alluvial valley of St. Vrain Creek. Regional geologic mapping (Colton, 1978) <br />shows that the alluvium in the north part of the site and the area adjacent to Dry Creek is mapped as <br />CIVIL AND ENVIRONMENTAL ENGINEERING PLANNING <br />