Final report for SNL/NM environmental drilling project Page: 76 of 109
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Set up to pre-bore for the sampler using the 1 3/4 in. conical non-steerable point. The first
sample attempt was to be at 10 ft. so the bore was made to 8 ft. without difficulty, the rods tripped
out and the sampler with transmitter housing attached. The tracking system was used at the end of
each rod to set a flag and obtain a depth reading. The sampler was then pushed to 10 ft. cocked
(withdrawn) with 1/2 rod then driven in 1 full rod (4 ft.). It appeared from the tracking data that the
bore path was at an upward angle, possibly due to the sluffing of the gravel at the entry point causing
the rod to deflect upward at entry. Also, there was considerable difficulty with the P-80 cylinder
dragging on the rod during both forward and reverse cylinder travel. The gravel seems to have a
very loose grip on the rods. The sampler was recovered but did not contain a sample. The entry to
sampler was packed with a clay-like material with a small hole in the center and an internal shape
conforming to the cone rod point. Apparently, the cone rod had retracted but not far enough to latch
up until withdrawal. The second attempt was a 20 ft., the bore was made to 18 ft. with the conical
point as before. This time the rods were withdrawn 3 ft. for cocking and then inserted 6 ft. to obtain
the sample. The sampler again came out without a sample. For the third attempt the hole was pre-
drilled for 7 rods (28 ft.), the sampler installed for an attempt at 30 ft. For this attempt a full rod
was used to set the sampler latch and this rod plus an additional rod to take the sample. During the
second rod a loud pop was heard. This was not unusual as similar sounds are made frequently during
the pre bore with the cone point. However, in this case, the sampler had broken off at the cone rod
thread where it screws into the rod adapter. The surface was flagged over the point where the
sampler had broken off to enable it to be recovered using a backhoe.
The fourth try was done as before with the sample target at 39 ft. The sampler was set with
3 cylinder strokes (--30 in.) then two additional strokes used to get a sample. This time the sampler
performed normally, the sample tube was packed with dry white sand. The sample tube was capped,
dated and presented to WHC.
Conclusions From The Sampler Testing
The Hanford geology presents several problems to the punch/core type devices typically used
with soil mechanics-type testing equipment for which the device used here was designed. The
locations of interest usually contain high ratios of rock to sand. The rocks are of very little interest
analytically so in order to have a viable sample you must recover the fine materials in which the
contaminants are trapped. To accomplish this in a gravel bed the push distance with the sampler in
the cocked position is necessarily longer than it would be for soil. This, of course, increases the risk
to the cone rod which has been recognized as vulnerable to breakage as it has happened before.
However, the system did work and it did get a sample. There is a need to increase both the strength
and sample volume of this sampler and to also make an attempt to somehow prevent the opening from
plugging off with stones. The other more serious problem of the cone rod breakage may be a simple
matter of increasing the diameter and/or the heat treat of the rod. It is planned at this time (April
1993) to look into reducing the cone rod vulnerability and to design and build a prototype sampler of
on the order of 2.25 in O.D. for the P-80 and possibly a 3 in. version for the X-810.
A later attempt to retrieve the broken sample was unsuccessful, the hole dug continued to fall
in and they could not find it (Ben Volk, WHC).
Using The P-80 To Bore A Pit To Surface Hole (See HAN3TRK1.XLS and Fig. 4)
Saturday 3/6/93
With the trench box set up as for the sampling a 2 in. steering head and transmitter were
installed to bore a pit to surface hole under the hill and to the surface in a flat area about 120 ft.
away. The first attempt entered the same hole as that used for sampling. Seven rods (28 ft.) were
pushed and it was determined the upward trajectory precluded doing an experiment to see if we could
steer the hole. We then tripped out and started a new hole with a level trajectory. The tracking
sonde used for this type of drilling transmits through the earth to a surface walkover receiver whichA-21
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Wemple, R. P.; Meyer, R. D.; Staller, G. E. & Layne, R. R. Final report for SNL/NM environmental drilling project, report, November 1, 1994; Albuquerque, New Mexico. (https://digital.library.unt.edu/ark:/67531/metadc1280825/m1/76/: accessed July 18, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.