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GEOTECHNICAL STABILITY EXHIBIT <br />This information is presented to address the plan to mine within <br />200 feet of the structures listed in Exhibit S. This analysis is <br />presented because some of the adjoining structure owners have <br />elected to not sign Damage Liability Agreements for this mine. <br />In the EXPANSION AREA SOUTH where new mining will take place the <br />structures are located along Brighton Road. This places them <br />from 5 to 20 feet above the area to be mined. The natural angle <br />of repose for gravel in this area is 2:1 and the gravel depth <br />averages 25 feet deep along the east side of the mined area. <br />The normal formula with a safety factor for determining the <br />vertical face setback is: Setback=Depth x 2.0. The Bromley Road <br />is the closest structure without a signed Damage Liability <br />Agreement to the mining area and it is 20 feet from the permit <br />boundary. In this mine a 25 foot setback is planned along the <br />permit lines so an additional 5 feet will be left between the <br />property and the vertical face. Backfilling will progress on the <br />mined area and against the east face once the gravel is removed <br />to the shale. This will be done to keep the face from failing and <br />moving the hole west creating a greater setback from the struc- <br />tures. <br />22 <br />