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D. Sites of Special Geologic Interest (G.l.d.) <br />There are no known or suspected sites of special geologic interest (e.g., fossil beds) at <br />this site. No features of special geologic interest are anticipated to occur because the <br />site is located within an extensive outcrop of Precambrian metamorphic rocks that are <br />prevalent in the Front Range from west of Colorado Springs north to west of Fort <br />Collins. <br />E. Geologic Hazards (G.l.e and G.I.f) <br />According to Section 48: G-H of the Jefferson County Zoning, a Geologic Hazard <br />Overlay District has been established to address four (4) types of geologic hazards: <br />slope failwe complexes, landslide azeas, rockfall areas and subsidence azeas. <br />Geologic Hazard Overlay District Zoning Maps have been created to help regulate <br />development in azeas susceptible to these geologic hazards. <br />The Elk Creek Quarry is located in an azea well outside (south and west of) any <br />existing Geologic Hazazd Overlay District Zoning Maps. Therefore, any concerns <br />about geologic hazazds at the site would address unzoned or other geologic hazards. <br />There is no evidence at the site of slope failwe, Landslide azeas or subsidence. <br />Rockfall azeas exist as part of the active mining operation within areas that will be <br />completely mined out before establishing final benches and highwalls. <br />Earthquakes, seismic shaking and liquefaction are not considered to be geologic <br />hazazds at the site. The potential for radon gas in this part of the County is beyond <br />the scope of this geologic report and site radioactivity potential is addressed by Elk <br />Creek in another part of the rezoning application. <br />F. Slope Stability (G.l.g ) <br />In order to provide an updated evaluation of slope stability at the site, Brierley <br />performed structural geologic mapping of rock mass discontinuities exposed at the <br />site, and made generalized stability analyses based on these data. Bedrock exposures <br />at the site primarily reveal foliation jointing subparallel to metamorphic <br />compositional layering. The foliation strikes northwest and dips from shallow to <br />moderately steeply to the northeast, generally into the hillside that is being mined. <br />Secondary joints that are steeply dipping to subvertical also occur. Finally, tertiary <br />joints exist that dip northwest to southwest, or generally out of the hillside that is <br />being mined. The foliation joints aze persistent across the site. The subvertical joints <br />are persistent for up to 10 to 25 ft. The tertiary joints that daylight in the cut slopes <br />are only persistent on the scale of several feet based on the exposures to date. <br />The joint mapping data is summarized in both spreadsheet and stereonet format in <br />Attachment C and the following average joint data aze interpreted from these <br />mapping data: <br />JC 00772 <br />PetersonfElk Creek <br />