EnviroProbe Integrated Solutions Inc. in Nitro, W.Va., completed an environmental site assessment using both drilling and direct-push applications.
EnviroProbe Integrated Solutions Inc. in Nitro,
W.Va., completed an environmental site assessment (ESA) using both drilling and
direct-push applications. The results of the ESA indicated the need for
installation of permanent ground water monitoring wells on the residential
property to depths of 85 feet. A previous drilling company was unsuccessful in
setting the wells using hollow-stem auger methods, primarily due to the
heaving/flowing sands in the subsurface.
The EnviroProbe field team, with a Geoprobe 8040DT combo rig, completed
the ESA work with no problems.
At a later date, EnviroProbe used its 8040DT rig to install two 2-inch
prepacked screen monitoring wells, each to a depth of 85 feet using the
direct-push feature of the rig. For the process, the field team used DT45
tooling to collect continuous soil samples. A 6-inch-diameter cutting shoe with
expendable knock-out was used to allow for the installation of the 2-inch
monitoring wells that meet the minimum borehole diameter for a 2-inch well.
Once at depth, the field team knocked out the expendable shoe, and installed
the PVC well through the DT45 casing. As the rods were extracted, Dale Kestner,
EnviroProbe’s driller, installed additional filter sand, a bentonite filter
pack seal, and annulus space seal.
“Our 8040DT rig continues to perform for us,” says Rod Moore, EnviroProbe’s
owner. “The advantages of owning and using this rig make our jobs easier. It
allows us to complete a wide-range of jobs with just one
rig.”
Moore lists several reasons for the success of this project – time, cuttings,
subsurface conditions, safety and cross contamination.
In approximately six hours, En-viroProbe set up, collected two soil borings (continuous
dual-tube soil sampling), set two two-inch PVC wells to 85 feet, and cleaned up
the site. Using the standard methodology (hollow-stem auger and continuous
standard penetration test sampling), this project would have required a
three-man drill crew and approximately two days to three days to complete,
while causing damage to the residential yard. “Our method saved our client a
minimum of $2,500, and one-to-two days field time,” Moore says.
EnviroProbe produced less than one drum of soil cuttings during the ESA. Normal
hollow-stem auger drilling probably would have produced a minimum of eight to
10 55-gallon drums of cuttings, which would have required disposal. “This also
saved our client at least $2,500 in transport and disposal costs,” Moore
adds.
EnviroProbe’s system eliminated the heaving or flowing of sands into the rod
string. “Prior to our arrival onsite,” Moore explains, “the hollow-stem auger
method caused significant heaving/flowing sands through the liquefaction and
mixing of the sandy saturated zone.”
Using the direct-push feature of the rig and the DT45 tooling, the field team
avoided the need for rotary drilling, eliminating the risk associated with
turning augers.
Hollow-stem auger methods typically will promote drag-down
(cross-contamination) of shallower contaminants into the subsurface and ground
water. The ability to push/hammer the casing eliminates the effects of
drag-down.
“Sometimes we wonder whether the job will be too much for our rig, but it
continues to do a great job for us,” beams Moore. “We’re especially pleased
with the power this rig has. It hasn’t disappointed us yet.” ND