(3) During the slurry placement the keywall on the north end of the crater on the exposed reef can be constructed. It is estimated that 1/2 of the keywall on the north (seaward) side of the crater will be anchored 1'-O into firm coral reef and the remaining 1/2 of the key wall will be embedded to a maximum of 8'-O into factured coral reef and where no reef exists. The applicable keywall to use will be determined in the field. oN (4) The amount of contaminated materianay eee be known by * ae this time and the configuration of the mound determined. of The location the keywall should be staked out and all surrounding material within the containment area removed to the elevation of the existing coral reef located on the north end of Cactus Crater, (5) Complete construction of the enclosing keywall. (6) Placement of the contaminated concrete mix above the water line shall be compacted by vibrator roller and shaped to receive the concrete cap. b. Keywall, The concrete keywall will be constructed completely around the encrypted material. The pace data (reference 7) indicates (Rev. 16Dec76)