Water Reservoirs and wetlands are a major source of methane emissions contributing to greenhouse gases. The annual flood seasons contribute to movement and accumulation of sediments behind irrigation and hydropower dams. These sediments accumulate year after year, lead to loss of water storage capacity and ability to produce hydro-electricity. The invention being proposed to dredge deep sediments from reservoirs operates on the principle of using gaseous fuel from an external pipeline or collected methane emissions as fuel for a submersible internal combustion slurry system. The invention combines the features of an internal combustion liquid piston engine with a slurry turbine driving a dredging cutter. Slurry entering into the system forms a column that is set in oscillation through the explosion of air and fuel and is then pumped to shore.

A trench cutting apparatus and method, the apparatus comprising a central support element comprising at least one jetting outlet and a cutting element configured to be driven around the central support element. The trench cutting apparatus is configured to be operable in a mechanical cutting mode in which the cutting element is driven around the central support element to cut material forward of the trench cutting apparatus, and a jet cutting mode in which a pump is activated to eject fluid from the at least one jetting outlet to fluidize or cut material forward of the trench cutting apparatus.

A microtrencher having a vacuum system configured to clean spoil from a microtrench having a rotating brush. A method of using the microtrencher to cut a microtrench in a roadway and using the vacuum system to clean spoil from the roadway and microtrench.

A cutter suction dredger includes a vessel, a ladder extending away from the vessel, a cutter head positioned at a distal end of the ladder and configured to contact a bed of the body of water to cut into the bed, and a bearing assembly. The bearing assembly includes a first spherical thrust bearing configured to resist thrust forces generated by the cutter head contacting the bed, a second spherical thrust bearing positioned opposite the first spherical thrust bearing, a symmetrical spherical bearing positioned between the first and second spherical thrust bearings, and a housing surrounding the first and second spherical thrust bearings and the symmetrical spherical bearing, the housing mounted to the ladder. A shaft extends along the ladder and through the bearings and the housing, the cutter head coupled to a distal end of the shaft.

A microtrencher having a vacuum system configured to clean spoil from a microtrench having a rotating brush. A method of using the microtrencher to cut a microtrench in a roadway and using the vacuum system to clean spoil from the roadway and microtrench.

A microtrencher having a vacuum system configured to clean spoil from a microtrench having a side shroud and a suction nozzle. A method of using the microtrencher to cut a microtrench in a roadway and using the vacuum system to clean spoil from the roadway and microtrench.

A trench cutting apparatus and method, the apparatus comprising a central support element comprising at least one jetting outlet and a cutting element configured to be driven around the central support element. The trench cutting apparatus is configured to be operable in a mechanical cutting mode in which the cutting element is driven around the central support element to cut material forward of the trench cutting apparatus,and a jet cutting mode in which a pump is activated to eject fluid from the at least one jetting outlet to fluidize or cut material forward of the trench cutting apparatus.

A control system for controlling operation of a cutter motor and a cutter boom movement mechanism of a machine includes a sensor that measures an amount of load associated with the cutter motor. A controller determines whether the load on the cutter motor is different from a cutter motor load limit. If so, the controller is configured to adjust a velocity of the cutter boom movement mechanism relative to a tip velocity of a rotary cutting tool associated with the machine based on the difference between the measured cutter motor load and the cutter motor load limit until a torque error of the cutter motor reaches a particular value, for instance, zero. Moreover, the controller may also adjust a current speed of the cutter motor in driving the rotary cutting tool based on the adjusted velocity of the cutter boom movement mechanism.

A cutterhead for dredging water-bed material from a body of water. The cutterhead comprises a shroud presenting a front margin for receiving water-bed material into an interior space of the shroud. The shroud additionally includes a port from which water-bed material can be removed from the interior space of the shroud. The cutterhead additionally comprises a rotatable cutterbar at least partially received within the interior space of the shroud. The cutterhead further comprises a debris guard positioned between the cutterbar and the port. The debris guard is operable to filter the water-bed material removed from the shroud through the port. At least a portion of the debris guard that faces the cutterbar includes a concave shape.

A system for harvesting natural gas from a clathrate deposit includes a storage system and a processing system. The storage system is located at a surface of a body of water and is configurable to couple to a conduit for receiving a slurry including clathrate hydrate pieces and natural gas from an underwater apparatus. The processing system is coupled to the conduit and is configured to separate the natural gas from the slurry.