428

RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL

effects of tides and stormson the containmentsite.>!.52 It was designed ty
last only 2 years, until containment was complete.°3-54 Due to unforseen

on-site changes, construction of the mole began 4 April 1978

approximately 9 monthslater than envisioned in the earlier planning. This

late start did mot permit its completion prior to the beginning of
containment operations.

Construction of the mole wasinitially constrained bydifficulties in roc,
deliveries from the quarry on South Runit. On | April 1978, the Pop
quarry permit was amended to permit an additional quarry on the reer

adjacent to Lacrosse Crater. Use of this quarry considerably reduced the
haul distance and eliminated delays in crossing the hotline. The mole
construction rate increased substantially after the new quarry was opened,
Even so, the mole was only 20 percent complete when tremie operations

began.55 When Typhoon Alice struck in early January 1979, the heavy

seas and huge waves dumped large amounts of sand into the crater.56
Since the mole wasstill less than half complete, a fair evaluation of its
effectiveness against such storm actions could not be made.
To facilitate mole construction and debris cleanup, the CJTG
recommended that the numerous contaminated concrete blocks near the
north quarry be used in the mole.5? Field Command did not concur

because of the contaminated nature of the material.58 Much later,

however, approval was given to use rejected keywall sections of
noncontaminated concrete in constructing the mole.
Construction on the mole was completed on 21 October 1979, several

weeks after the crater container had been capped.5? It was far enough

along during the capping operations, however, to serve its intended
purpose. The mole was subsequently improved to the extent that it would
provide continuing protection for the containment structure.

TREMIE OPERATIONS
Dueto delays in starting soil cleanup, there were only about 3,700 cubic

yards of soil in the Runit stockpile when tremie placement began.® The

tremie facility consisted of a concrete pump which forced slurry through a
5-inch flexible pipe constructed across a floating footbridge to a crane

mounted on a barge floating in Cactus Crater (Figure 8-21). The feeder
pipe was connected to an 8-inch-diameter pipe suspended from the crane
boom as a placementdevice (Figure 8-22). Cables anchored on the shore

and connected to winches on each corner of the barge were used to move
the barge about in the crater.
The tremie mix was deposited into transit-mix trucks at the batch plant
in the industrial area north of the hot line. The mix contained three bags of

Select target paragraph3