434 —~—w RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL above the reef level to an average keywall diameter of 377 feet. The total crater fill included 4,500 cubic yards of contaminated debris, 7,109 Cubic yards of oversize material, 47,500 cubic yards of loose soil, ang an undetermined amount of sand deposited by storm and tidal action. The soil compaction ratio for loose soil to volume filled in the tremie operation was 1.23:1.73 THE STOCKPILE SIZE QUESTION When tremie operations ended on 10 February 1979, CJTG noted 4 significant difference between the actualsize of the stockpile of remaining contaminated soil on Runit and the running balance sheet calculation of stockpiled soil, as reported by USAE and maintained on JTG records. 4 physical survey indicated there were approximately 3,500 cubic yards in the stockpile rather than the 28,121 cubic yards carried on JTG books based on USAE reports of volume of soil transported to Runit less the USAE reports of volume of soil encapsulated by tremie operations.74 4 similar discrepancy had appeared in reporting soil remaining to be transported from Enjebi to Runit. Detailed investigation revealed that several factors were involved in these discrepancies including estimating errors, counting errors, variations in truck loading, not taking into account the expansion of volume which occurs when soil is removed from its natural location, and the compaction which occurs when soil is combined into a slurry. When the error was reported during the 12 February Fission Products Survey Conference, it was perceived by the planners there as a mixed blessing. It meant that additional dome capacity and time, as well as the resources, would be available for containing contaminated soil from other locations, e.g., Lujor and Runit. KEYWALE CONSTRUCTION The keywall was designed to prevent scouring and undercutting of the containmentstructure. The design mix was for six bags of cement (Type If) per cubic yard of concrete, subject to final determinationin the field.’ This would produce concrete with a compression strength of not less than 3,000 pounds per square inch (psi) at 28 days. The USAE determined by field tests that a 6.3 bag mix consistently gave results in excess of 3,000 psi compression strength. Construction of the keywall in 10-foot sections was specified in the design. USAE surveyors laid out and staked the centerline for the keywall during the first week in October 1978.76 The minimum radius providedin |