32
!
28
|
240-20
|
16
I
I
12
{
g
I
APPROXIMATE
SHORELINE
— a
ee
ae
eee
~
7
— 6
- 1
~ 8
tics bere eran gneves
-—4
— 0
—
4
LEGEND
+ = 25.08 50 M GRID STAKE
— 68
© = AUGERED PROFILE LOCATION (163
a=
0 = SIDEWALL PROFILE LOCATION (66)
X = SURFACE, 10 AND 20 CM COMPOSITES (29)
& = NUCLEAR TEST GROUND ZERO
12
16
— 2
— 2
— 28
FIGURE 6-18. SUBSURFACE SAMPLING LOCATIONS ON ISLAND JANET PRIOR TO 25 APRIL 1978
first priority for soil profiling was assigned to Sally.
Profile pits were dug and sampled at many
selected locations in the Kickapoo and Yoke/Yuma areas in search of pocket boundaries; in some
places, sampling was on a 6.25 m grid in an effort to reduce the volume of soil to be excised while
strictly adhering to cleanup criteria.
Collection of large numbers of samples continued to be the normal mode of operation during
subsurface investigations on Irene, Janet, and Pearl. Each sampling mission generated a backlog of
samples for the laboratory; the next iteration of sampling, if required, had to wait until results of the
prior iteration were available. Even though profile locations were carefully and thoughtfully
selected, many locations which might have been omitted were sampled on a 6.25-m grid. Much
thought was given to finding ways to reduce the number of profile pits dug, and therefore, the
number of samples requiring laboratory processing.
operation are described in the next section.
Significant improvements to the mode of
Pockets of subsurface transuranic concentrations exceeding excision criteria were located and
removed from Irene, Janet (Figure 6-21), and Sally, using the methods described above. After the
required volume of soil had been removed, additional soil samples were taken from excavation-site
sidewalls to verify satisfactory excision. Excavation at one site on Irene and at the two sites on
Janet required several iterations of progressively smaller excisions before all evidence indicated
compliance with criteria. The final evidence in each case was an IMP gamma sean of the cleaned
area.
If the excavation was backfilled and/or recontoured to smoother slopes, then the final
configuration was again gamma scanned by IMP.
187
|
arin
0 50 100
METERS