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June 14.1999 <br />Ms. Angela Bellantoni <br />Hard Rock Paving &Redi-Mix, Inc. <br />P.O. Box 1720 <br />Canon City, Colorado 81215 <br />Subject: Geotechnical Engineering Evaluation, Hard Rock Paving &Redi-Mix, Inc., Buena <br />Vista Gravel Pit, Buena Vista, Colorado <br />Project No. 99060 <br />Dear Ms. Bellantoni: <br />This letter presents the results of a geotechnical engineering evaluation performed for the subject <br />site. The purpose of the investigation was to evaluate the potential for damage to adjacent <br />properties as a result of proposed mining activities. The investigation was performed in general <br />accordance with our proposal P-99-016, dated May 28, 1999. <br />The approximately 23.8-acre gravel pit is to be located within Section 5, Township 14 South, <br />Range 78 West at the north end of Chaffee County Road 383 in Buena Vista, Colorado. The site <br />was previously mined and partially reclaimed. The northwest corner of the pit has been graded to <br />an approximate slope of 2 horizontal to 1 vertical. The base of the pit is an approximate elevation <br />of 8030 with pit walls on the east, west and south being near vertical to an approximate elevation <br />of 8050. The natural ground surface on the remainder of the site slopes gently down to the south <br />with approximately 25 feet of relief across the site. The natural ground surface is covered with <br />Pinon trees, shrubs, grasses and cacti. <br />Information on the subsurface conditions at the site was obtained from field reconnaissance and <br />review of the "Reconnaissance Geologic Map of the Buena Vista Quadrangle, Chaffee and Park <br />Counties, Colorado," by Glenn R. Scott, United States Geological Survey, MF-657, 1975. Geologic <br />units described by Scott and observed in the field include: <br />Q, -Fan Alluvium -Yellowish-gray to dark gray to brown subangular coarse sand <br />derived from weathered oranodiorite or from alluvium. Scott estimates this unit may <br />be up to approximately 50 feet in thickness. Fan alluvium was observed along the <br />northern boundary of the site and at the base of granodiorite rock outcrops on the <br />adjoining property to the north. <br />QPoo - Outwash of Pinedale Glaciation -Yellowish-gray crudely stratified alluvium <br />containing well-rounded to subrounded boulders, cobbles, gravel and sand. <br />Composed of Tertiary igneous rocks and Precambrian metamorphic and igneous <br />rocks and forms the upper terrace above the Arkansas River. Boulders present <br />were emplaced by two catastrophic floods from breakouts of glacial dams at Pine <br />Creek. The average size of boulders is 4 to 6 feet. Scott estimates the thickness of <br />the outwash to be approximately 10 to 60 feet. This unit was observed in the sides <br />of the existing pit as well as in the slopes along the railroad tracks on the eastern <br />boundary of the site. <br />rn 0 U t. T ..:, i rl /\ ~~ Plr 7191539.2312 1537 G St • Salida, CO St201 <br /> '_~ Fx 719,~53Q9111 metsal~dz@bemail com <br />