Laserfiche WebLink
4. We concur that the favorable attitudes of the dominant foliation jointing into the <br />hillside is generally compatible with the originally proposed 1:2 (H:V) slope ratio. <br />Additional discussion about slope stability and proposed steepened slopes is <br />included in the slope stability section below. <br />Finally, the Geologic Map of.Cotorado; (1:500,000) indicates two northwesterly faults <br />transecting or passing just southwest of the site. These faults would be considered <br />inactive and cut across the both the Precambrian metamorphic rocks that occur <br />southeast of U.S. 285 and the slightly younger granitic rocks (Silver Plume Quartz <br />Monzonite and Pikes Peak Granite) that occur northwest of the highway. <br />B. Site Topography (G.l.b) <br />The site location and topography are discussed in detail in the attached Fox report <br />submitted as part of the original DMG permitting and those details aze not repeated <br />herein. Additional comments about site topography for the present rezoning effort <br />include the foIlowing: <br />1. Pre-mining slopes at the site were closer to approximately 2:1 than 2.5:1 <br />as reported in the Fox report. <br />2. The cut slope along the west side of U.S. 285 across the highway from the <br />quarry is approximately 1:1 overall, and steeper in the lower cut face. <br />3. Historic mined and reclaimed slopes by others at the site are as steep as <br />1:2 and appear to be generally stable. <br />A site topographic map was included in the original DMG permit application. This <br />map is included as Attachment A to this report. The Geologic Map prepared for this <br />report and included in Attachment B also shows the pre-mining topography. In <br />addition, Elk Creek has developed a very detailed site topographic map pi epazed by <br />Falcon Surveying, Inc. based on a June 2, 2004 field survey. A copy of the new <br />detailed topographic map showing existing conditions (1 in. = 40 ft; 1 ft contour <br />interval) is provided elsewhere in the rezoning submittal. <br />C. Test Borings or Core Samples (G.l.c.) <br />No test borings were performed and no core samples were obtained as part of original <br />site permitting efforts. Since that time quarry development has occurred and there are <br />ample bedrock exposures at the site to preclude the need for. test drilling to identify <br />site lithologies. Topsoil and overburden thicknesses are negligible, varying from less <br />than a foot to approximately 3 ft thick. There is an upper weathered bedrock zone in <br />which moderately severely weathered to completely weathered bedrock extends <br />approximately 15 to 20 ft into the rock mass. Bedrock exposures at the site have been <br />mapped for geologic structure and these data are included in the slope stability <br />section below. <br />JC 00774 <br />PetersonlElk Creek <br />