Hydro excavation apparatus for excavating earthen material are disclosed. The hydro excavation apparatus includes a first reservoir for holding a base fluid therein, a second reservoir for holding an additive therein, a vacuum system for removing earthen material from an excavation site, and an additive dosing assembly. The additive dosing assembly includes at least one of a pump and a valve fluidly connected to the second reservoir. The additive dosing assembly is selectively controllable to introduce an additive into at least one of the base fluid and the removed earthen material.

A method for recovering rare-earth mud including steps of: (A) penetrating a mud gathering pipe into a layer containing rare-earth mud under the seafloor, (B) preparing a slurry containing a rare earth by loosening rare-earth mud in the mud gathering pipe, and (C) transferring the slurry through a mud raising pipe. A rare-earth mud recovery system including: a mud gathering pipe configured to penetrate into a layer containing rare-earth mud under a seafloor; a stirring device configured to loosen rare-earth mud in the mud gathering pipe; and a mud raising pipe connected to the mud gathering pipe.

A vehicle may include an undercarriage with a vacuum spoils tank and a multi-cyclone body housing mounted thereon. A vacuum spoils tank may be in fluid connection to the multi-cyclone body housing. The vacuum spoils tank may include both an inlet and an outlet. A multi-cyclone body may be housed within the multi-cyclone body housing. The housing may be positioned at the vacuum spoils tank outlet, and the multi-cyclone body may carry a plurality of mini-cyclonic chambers. Each mini-cyclonic chamber may include an outlet tube and a mini-cyclonic separator. The mini-cyclonic separator may be in fluid communication with the vacuum spoils tank outlet. The outlet tube may be in fluid communication with a multi-cyclone body housing outlet and a filtration system

Mixing systems that include a mixer housing and one or more disk assemblies for mixing and processing materials is disclosed. The disks rotate to mix an additive into the material and to carry agglomerated solids toward a discharge of the mixing system. The disks may have a plurality of fingers or lobes which extend from a central portion of the disks.

A method and apparatus for generating a slurry from the surface of the subsea floor, separating that slurry into multiple slurries, and pumping the desired slurry to the surface.

Systems for reducing or preventing pluggage of spoil material in an excavation vacuum apparatus are disclosed. The pluggage prevention system of the excavation vacuum apparatus may trigger one or more mitigation operations (e.g., addition of water through spray nozzles) to loosen the build-up of spoil material and/or to at least partially shut down the excavation vacuum apparatus to prevent more material being fed to the system.

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.

Mixing systems that include a mixer housing and one or more disk assemblies for mixing and processing materials is disclosed. The disks rotate to mix an additive into the material and to carry agglomerated solids toward a discharge of the mixing system. The disks may have a plurality of fingers or lobes which extend from a central portion of the disks.

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 diaphragm wall cutter for cutting a cutting trench in the ground, comprising a cutting frame, at least one rotatably drivable cutting wheel which is mounted on an lower side of the cutting frame, a suction nozzle, which is arranged in the region of the at least one cutting wheel and is provided with at least one suction opening, and a suction pump which is configured for suctioning slurry from the cutting trench during cutting via the suction nozzle, the suction pump being connected to the suction nozzle via a suction line. According to the invention, it is provided that at least one filling port is provided for filling the suction pump and the suction line with a liquid when the suction line is shut-off, wherein the suction line and the suction pump are filled with liquid for starting the suction pump.