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LAWS’ unique, 10”
cutter suction dredger, is mobilized to site
by road and craned into the water-body using
a mobile crane (total mass = 14,300kg). A
fixed pipeline is then established alongside
the foreshore using a small, tracked
excavator to deploy the pipeline. The fixed
pipeline will discharge to a purpose made
settling lagoon (excess waters arising from
the settlement process are back-pumped or
gravity fed to the water-body in which the
dredger is operating). The dredger is
connected to the fixed pipeline on the edge
of the water-body using a floating, flexible
umbilical pipeline.
Dredging is undertaken
in a series of parallel cuts (in a similar
fashion to a combine harvester), by a
shrouded dredge head which is lowered
beneath the dredger on a fixed arm. The
dredge head comprises a scroll feeder (the
“cutter head”) which agitates the
sediments within the dredge head/shroud and
feeds them directly into the mouth of the
pump which is mounted immediately behind the
scroll. The fixed dredge arm is pivoted
beneath the dredger on a winch operated
gantry and has a maximum dredge depth of
6.7m. The slow rotation of the scroll feed
within the dredge head shroud mitigates the
turbidity and local impact of the dredge
operation.
The
dredger is positively positioned with the
hydraulically driven star wheels (propelling
the vessel along the floor of the
water-body) or by means of deck mounted
hydraulic winches on a guide wire system.
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Road
Transportable Cutter Suction Dredger,
Dredging Cohesive Mineral Waste (note one of
the Star Wheel drive units is raised at the
rear).
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Once inside the pump
the sediments are mixed to an approximate
concentration of circa 15-20% solids (80-85%
water), and pumped down the pipeline as a
thoroughly mixed solution.
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Pumped
Discharge of the Dredge-Mixture
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