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E. Geologic Hazards (G.1.e and G.1.f) <br /> According to Section 48:G-H of the Jefferson County Zoning, a Geologic Hazard Overlay District has been <br /> established to address four(4)types of geologic hazards:slope failure complexes, landslide areas, <br /> rockfall areas and subsidence areas. Geologic Hazard Overlay District Zoning Maps have been created to <br /> help regulate development in areas susceptible to these geologic hazards. <br /> The Elk Creek Quarry is located in an area well outside(south and west of)any existing Geologic Hazard <br /> Overlay District Zoning Maps. Therefore, any concerns about geologic hazards at this site would address <br /> unzoned or other geologic hazards. There is no evidence at the site of slope failure, landslide areas or <br /> subsidence. Rockfall areas 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 hazards at the site. The <br /> potential for radon gas in this part of the Country is beyond the scope of this geologic report and site <br /> radioactivity potential is addressed by Elk Creek in another part of the rezoning application. <br /> F. Slope Stability(G.1.g) <br /> In order to provide an updated evaluation of slope stability at the site, Brierley performed structural <br /> geologic mapping of rock mass discontinues exposed at the site, and made generalized stability analyses <br /> based on these data. Bedrock exposures at the site primarily reveal foliation jointing's subparallel to <br /> metamorphic compositional layering. The foliation strikes northwest and dips from shallow to <br /> moderately steeply to the northwest,generally into the hillside that is being mined. Secondary joints <br /> that are steeply dipping to sub vertical also occur. Finally,tertiary joints exists that dip northwest to <br /> southwest,or generally out of the hillside that is being mined. The foliation joints are persistent across <br /> the site. The sub vertical joints are persistent for up to 10 to 25 ft. The tertiary joints that daylight in <br /> the cut slopes 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 Attachment C and <br /> the following average joint data are interpreted from these mapping data: <br />