A method of dewatering a tailings lagoon retained by a dam comprising: excavating an excavation hole in the tailings lagoon; allowing water from surrounding tailings to enter the excavation hole; and pumping water in the excavation hole out of the excavation hole and discharging beyond a toe of the dam. Also disclosed is a method comprising: excavating a channel in a tailings lagoon from a shore of the tailings lagoon and floating a pontoon in water in the channel from the shore along the channel,wherein: excavating involves breaking down solid tailings in the tailings lagoon into a slurry using water and removing the slurry using a submersible slurry pump mounted on the pontoon.

The invention relates to a manoeuvrable trailing dredging vessel comprising; a vessel propulsion member coupled with a propulsion shaft provided with a single gear for driving the propulsion member, a drive system having a central drive shaft coupled with the vessel propulsion member for providing power to the vessel propulsion member, a transmission device having at least a trailing transmission shaft provided with a trailing pinion and a sailing transmission shaft provided with a sailing pinion, wherein the central drive shaft is coupled with the single gear of the propulsion shaft through one of the trailing transmission shaft and the sailing transmission shaft.

A dredging system for the removal and cleaning of sediment in bays, port entrances, navigable channels, docks, watercourses, lakes or reservoirs, which is provided with means for excavating, dragging and removing the bottom of the waterway and means for regulation and support, the driving force for which is provided from land, which facilitates extraction of sediments directly onto the land, immediately leaving a planar surface on the sea bed. The aforesaid is achieved by controlling the excavator means and very closely controlling the cutting depth, all in a shorter period of time and at lower cost.

An impeller for a centrifugal pump comprises a rotor; a shaft shield connected to the rotor and having an axial supply; a suction shield connected to the rotor and axially set apart from the shaft shield; and a plurality of blades between the shaft shield and suction shield and connected to the rotor. Each blade comprises a leading edge and a trailing edge connecting between the shaft shield and the suction shield and a suction side and a pressure side, wherein each blade cross-section is thicker near the leading edge on the suction and pressure sides, and tapers to a thinner cross-section near the trailing edge. Each blade connects to the suction shield at the leading edge with an extensive fillet providing curvature toward the suction shield along the leading edge.

A method of pumping material from a sea floor to a vessel on a sea surface, including the steps of collecting material from the sea floor using a production tool, connecting the production tool to the vessel with a riser including a riser transfer pipe, and pumping the material from the production tool to the vessel using a subsea slurry lift pump positioned between the production tool and the vessel and attached to the production tool by the riser transfer pipe. The method further includes backflushing the riser transfer pipe by running seawater through the slurry lift pump into the riser transfer pipe toward the production tool.

A dredging system for the removal and cleaning of sediment in bays, port entrances, navigable channels, docks, watercourses, lakes or reservoirs, which is provided with means for excavating, dragging and removing the bottom of the waterway and means for regulation and support, the driving force for which is provided from land, which facilitates extraction of sediments directly onto the land, immediately leaving a planar surface on the sea bed. The aforesaid is achieved by controlling the excavator means and very closely controlling the cutting depth, all in a shorter period of time and at lower cost.

An earth removal and sand mining system is provided, comprising a modular floating platform having an elongated U-shaped open channel defining an operating area; a gantry positioned above the operating area, wherein the gantry includes a crane and trolley operable along a predefined path within the operating area; a hoist extending from the trolley; and a pump operatively suspended from the trolley, wherein the pump includes a slurry discharge hose. The platform includes an adjustable drag line connected to the pump to enable control of the pump position.

The present invention relates to a system and method for uncovering and removing pipeline from the seafloor using a subsea trenching system using pressurized water to uncover pipe, a subsea shear carried by a barge to cut lengths of the pipeline, and a grapple carried by a barge to lift cut lengths of pipeline for placement on a pipe haul and recovery barge.

A method of pumping material from a sea floor to a vessel on a sea surface, including the steps of collecting material from the sea floor using a production tool, connecting the production tool to the vessel with a riser including a riser transfer pipe, and pumping the material from the production tool to the vessel using a subsea slurry lift pump positioned between the production tool and the vessel and attached to the production tool by the riser transfer pipe. The method further includes backflushing the riser transfer pipe by running seawater through the slurry lift pump into the riser transfer pipe toward the production tool.

The invention relates to a manoeuvrable trailing dredging vessel comprising; a vessel propulsion member coupled with a propulsion shaft provided with a single gear for driving the propulsion member, a drive system having a central drive shaft coupled with the vessel propulsion member for providing power to the vessel propulsion member, a transmission device having at least a trailing transmission shaft provided with a trailing pinion and a sailing transmission shaft provided with a sailing pinion,
wherein the central drive shaft is coupled with the single gear of the propulsion shaft through one of the trailing transmission shaft and the sailing transmission shaft.