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GEOTECHNICAL STABILITY EXHIBIT <br />There are no buildings or any structures outside the permit area which could be affected by the <br />excavation. A minimum 30 foot buffer will be maintained from the permit boundary line to all <br />new excavations. There will be no excavation within 30 feet of the property line. <br />1. Quarry Slope Stability <br />The Ralston Quarry is entirely contained within a basalt extrusion adjacent to Pierre shale that <br />has been uplifted. Basalt, like what is found in this quarry, is highly competent material that <br />facilitates mining to very steep slopes. The south, north, and east slopes of the quarry are entirely <br />contained within the basalt, and are therefore limited in their slopes by the basalt's geotechnical <br />properties and local jointing. On the west slope, the basalt -shale contact dictates the limits of <br />excavation and permanent slopes. <br />Brierley and Associates of Golden, CO performed a site specific analysis of the slope stability at <br />Ralston Quarry. This information can be found in Appendix 2. All mining and reclaimed slopes <br />within the quarry itself will be based on these reports and analysis. See Map C -4 for details of <br />the final slope configurations within the quarry. <br />Asphalt Paving Co. will adjust bench heights and widths within these limits to create slopes that <br />are aesthetically pleasing in reclamation. Also, internal slopes maintained during mining will <br />vary as necessary to facilitate mining, and to maintain safety standards. The slopes shown on <br />Maps C -3 and F are plan views of the maximums and minimums determined by Brierley, and are <br />used to illustrate the maximum possible build out of the quarry. The final slopes will vary and <br />adjust to the on -site geology. <br />2. Blasting <br />Seismic measurements are taken each year, and a report of these measurements is provided to <br />Asphalt Paving Co. A copy of the most recent report can be found in Appendix 3. <br />Ralston Quarry, April 2015 U -1 <br />