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voids or caverns in ttie bedrock, especially at the proposed dam Plo. 3 site. The coal slag, clean portions of sand and gravel, carbonaceous ' and lignaceous clays and weathered clay stone are not suitable for fill ' material and should be wasted. The clean sands and gravels may be suit- able for the filter material required for relief wells. Water will be ' encountered in some portions of the trenches, generally towards the east. Water may be handled by ditching and pumping. The contractor should be ' advised that some "softer" soil conditions may be encountered at or near the water table. This may require the use of a power shovel in order to excavate the bottom of the trenches down to medium hard bedrock. It may ' be advisable to dewater the trench areas prior to excavation by install- ing well points on north sides of trench areas. The ground water is higher ' on north portions of the area. ' 3. The foundation surfaces shall then be plowed or scarified to a depth of at least six inches, and smoothed until the surface is free from ruts, ' hummocks, or other uneven features which would tend to prevent uniform compaction by the equipment to be used. ' 4. After the foundations for the material has been cleared and any frozen ' material removed and plovred or scarified where necessary, it shall be disced or bladed until it is uniform and free f rom large clods, brought ' to the proper moi sture content and compacted to not less than 95a of maximum density a s determined by ASTM D-1557-70 (htodifed Proctor Test - 8 1/30 h bi 5 layers - 25 blows each - 10 pound hammer - 1 drop - cu inc c ' foot of mold). 5. Materials for the fill may be obtained from the anticipated borrow areas ' and from the clay soils excavated from the cut off trenches. Fill material ' should be free of all vegetation, frozen materi als and other deleterious 1 -6 -