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• • EXHIBIT D (COnt'd) <br />' quadrangle. There have been no site-specific tests to determine <br />' exact figures on porosity and permeability in the Church Pit area. <br />It is expected that the vertical permeability native to the sand- <br />, stone has been drastically reduced by the clay being worked along <br />' its top beading plane. <br />Overlying the clays of the basal Laramie is a quartzose <br />sandstone, also part of the Laramie (see Sketch 1). Clay Zone 3 <br />t <br />in its upper section changes laterally from clay to sandstone. <br />Since this porous, permeable sand overlays the clay material, it is <br />not expected that a Ieachate would reach this rock. <br />Overlying these steeply-dipping bedrock units at an angular <br />' unconformity is the Rocky Flats alluvium (Qrf) (see Sketch 1). <br />This alluvium is boulder and cobble gravel, predominantly quartzite. <br />The upper part of the alluvium varies from one to six feet in thick- <br />' ness and is a clayey to pebbley silt. Underlying this silt is zero <br />to six feet of gravel that is cemented with calcium carbonate. In <br />' the pit area this alluvium varies in depth from 2 to 16 feet but <br />can be as thick as 50 feet. <br />Operations. As each stage begins, the soils and overburden <br />' will be removed and stored for future use in seedbed preparation <br />and in backfilling and grading. Storage will be on the east and <br />' west sides of the pit. <br /> <br />1 <br />~' <br />8 (Revised) <br />