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-9- <br />• foundation level. across-section of the site is shown on Fig. 10. <br />Spread or mat type foundations bearing directly on the claystone bedrock <br />arc recommended and should be designed In accordance with the recommenda- <br />Lions presented below. <br />The walls of the hopper will be vertical and cast against adJacent <br />bedrock. The claystone bedrock does not appear to'exhlbit pronounced <br />bedding orientation but is, however, heavily Jointed with tight fractures. <br />For the maximum depth proposed of 28 feet below finished grade, we <br />believe near-vertical slopes can be cut provided the reinforced concrete <br />wall or shoring Is placed within a short period following excavation. <br />The rock fs sofa enough to allow a fairly neat slope but becomes harder <br />with depth. Concrete can be placed directly against the slope if a <br />i means of drainage is provided. In an open excavation, ripping appears <br />feasible; however, In confined areas, air spade or drilling and blasting <br />techniques will probably be required. Blasting should be with as light <br />a charge as possible. <br />Water seepage will be through the claystone bedrock and Tt should <br />be possible to dewater within the excavation. Permanent underdrains are <br />recommended. Lateral pressures for design of concrete walls are presented <br />below. <br />Crusher Building: The crusher building will be an above-ground structure <br />with slab-on-grade. Test Holes 3 through 6 indicate quite variable <br />subsoil conditions across the site. Swell-consolidation tests shown on <br /> Figs. 13 and 15 indicate that the clay Bolls possess erratic swell- <br />. consolidation characteristics. Because of the variable swell and depth <br />