se:
erations
soil Cleanup Op
walls, resulting in cave-ins.. The clamshell proved to be more
undercut the lifting soil and allowing water to drain back into the hole,
successfulgin
izin the spread of contamination. Thetest revealed the need for a
minim! | enclosure as there was a 33 percent increase in the width and
Lone the hole through cave-ins over a 24-hour period. Additional
lengt sations on 15 August and 29 September 1978 confirmed the results
investier tests; i.e., a constant water level 2 feet below the surface and
Ot table excavation walls which fell in on 1:3 to 1:10 slopes, depending on
watet movement.”
;
;
During the initial planning, Field Command requested that Pacific
Ocean Division (POD) of the Corps of Engineers submit designs for
excavations, including both open and sheetpile procedures. 41 A design
report was submitted on 15 September 197842 and, in a letter dated 6
October 1978, POD recommended that the JTG proceed to excavate
contaminated material without the use of sheetpiling. The proposed
scheme provided for a series of systematic overlapping trench excavations
since POD suspected that the contaminated material was no more than 6
feet deep within the boundariesof the old tidal pond. POD also believed
chat, even if it were required to go as deep as 18 to 20 feet, the excavation
could be accomplished with available equipment operated by skilled
personnel.
.
A meeting was to be held at POD offices in Honolulu on 6, November
1978 to make a final recommendation to DNA on procedures to be used
for removal of contaminated soil and debris from the Aomonburialsite.
The essential decision to be made was whether to select the PODrecommendedprocedureorto place sheet pile aroundall four sides of the
crypt. Also to be considered wasthe alternative to place sheetpiling around
three sides, with the end walls extended to the causeway prior to
excavation.43
AOMON CRYPT CONFERENCE: 8 NOVEMBER 1978
This meeting took place on 8 November 1978, attended by
representatives of POD, JTG, H&N-PTD, DOE-Pacific Area Support
Office, DOE-NV, DOE-Germantown, F&S, U.S. Army Support
CommandHawaii, Field Command, and Headquarters DNA.*4 Based on
decisionsat this meeting, the CJTG was given the following guidance:45
a. Start a drilling and core sampling program to determine vertical and
lateral extent of radioactive contamination within the crypt.
b. After completion ofinitial core sampling, begin excavating without
containment about | December 1978 in accordance with operational
concepts developed during the meeting.