PROJECT SPOTLIGHT
screens, separating larger particles through a hydrocyclone
to remove finer sands and silts,” said Males. “Slurry
is pumped tangentially into the system to create a vortex.
The heavier sand particles are separated from the mud
by centrifugal force and exit the bottom of the cone, and
the mud with finer particles exits out the top.”
Prior to installing the rebar cage, the Hydromill completes
a final cleaning. The process uses the Hydromill
wheels and suction pump to remove any sand or silts
that have settled to the bottom, as well as cleaning the
sides of the excavation. This process is critical to avoid
cement contamination during the pouring process.
Large prefabricated reinforced rebar cages of varying
sizes and configurations were lowered into the panel in
one length using a 200T Liebherr 895 Crawler Crane,
due to the immense length and weight of cages, which
each weighed up to 50,000 pounds. Once the cages were
lowered into the panel, the Keller team began installing
up to four tremie tubes through the reinforced cage to
near the bottom of the excavation.
“This tremie system allows concrete to be placed from
the bottom of the excavation, displacing the bentonite
slurry in the panel – which is then pumped back to the
desander for recycling,” said Males. “As sections of tremie
tubes were removed between rounds of concrete, it was
vital to maintain a minimum distance of tremie tube
embedment to ensure the quality of the concrete in the
Tremie concrete pouring
Keller workers removing rigging after lift
42 Issue 4 2021 www.pilingcanada.ca
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