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 Underwater
Vibracorer |
Rocky Mountain Soil Sampling has
recently acquired a Rossfelder Underwater Electrical Vibracorer. Working
from a suitable boat, this system can be used in water over 100 feet
deep to collect continuous core samples.
Cores barrels are three or four inch diameter and can be up to twenty
feet long depending on your application. Several choices in core barrel
materials are available including Stainless Steel and Aluminum as
well as clear plastic core liners.
The Rocky Mountain Vibracorer uses Contra-rotating Dual-eccentrics
and High-frequency vibrations of 8,000 VPM, and is ideally suited
for sampling the unconsolidated sediments of a marine environment.
Power is from a small generator with waterproof cables and extraction
by means of a small winch or crane system. If your program happens
to be in a remote site, the equipment is portable enough that we could
use "Vessels of Opportunity" if necessary.
How does Vibracoring compare to using other
methods of underwater sampling? Here is a brief comparison
of a few.
Using Commercial Divers to collect underwater cores, they usually
need to be in a three-man team. Divers have obvious physical limits
with their body and can only take limited samples usually by hammering
a core tube into the bottom. Doing this underwater can be quite a
challenge at times. Besides being potentially quite expensive for
this set-up, samples can suffer from what is called a 'Rodding Effect'.
This is where wall friction inside the tube exceeds the bearing strength
of the sediment layer you are sampling, causing sample recovery to
be limited at best until a harder layer is encountered below.
Another popular method is a clamshell 'Ponar' sampler. It is lowered
to the seafloor and takes a scoop of the bottom using its own weight,
then is pulled back to the surface. This is a great way to see what
the composition of the seafloor is, but penetration is limited to
about a foot deep.
One last method for drilling on the water is mounting a drill rig
on a barge and drilling with Hollow-stem augers and split-spoon samplers
through the middle. As well as the high cost of the barge and support
boat rental, depths are limited to 30-feet or so depending on your
location and water conditions.
We feel our new Vibracoring system is one of
the best methods of underwater coring available and we look forward
to using it on your next project.
Visit our photo gallery page for more pictures.
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