Deep sea mining apparatus

Undersea mining apparatus for recovering particulate matter on the ocean floor, said apparatus comprising:

• (a) conduit means for conveying particulate material in the form of nodules from the sea floor to a surface vessel, said conduit means having an inlet end adapted to be positioned adjacent the ocean floor and an outlet end spaced from said inlet end and defining a discharge opening to discharge collected nodules into a surface vessel;
• (b) pump means for providing a source of water under pressure;
• (c) collecting means connected to said inlet end of said conduit means for collecting nodules and for conveying collected nodules to said conduit means;
• (d) lifting means in communication with said pump means and connected to said conduit means for providing a lifting jet of pressuirzed water to cause said nodules to travel through said conduit means, said lifting means incluidng a submerged lifting chamber surrounding said conduit at a desired height of said conduit means above the sea floor and in communication with said pump means, said conduit means including a lift pipe extending from a point adjacent the ocean floor to said lifting chamber and a dredge pipe extending from said lifting chamber to a surface vessel, said lift pipe communicating with said lifting chamber and having an inlet opening adjacent the ocean floor and extending from the ocean floor and connected to said collecting means, said lift pipe having a parallel wall cylindrical outlet extending within said lifting chamber and defined by a first diameter substantially equal to the lift pipe diameter to define a substantially continuous cylindrical flow passage, said dredge pipe having an inlet within said lifting chamber and adjacent said lifting pipe outlet, said dredge pipe having an outlet positioned to discharge collected material into a surface vessel, said dredge pipe having a venturi including a converging section, a throat section defined by a second diameter smaller than said first diameter, and a diverging section, each in axial alignment to provide an axially-symmetric converging-diverging venturi, said lift pipe opening extending into said converging section of said venturi and defining therewith an annulus area therebetween, said annulus area communicating with said lifting chamber to permit pressurized water to pass through said annulus area and into said venturi to provide a pumping effect to lift the nodules through said conduit means to a surface vessel, said lift pipe outlet and said dredge pipe inlet being movable relative to each other to permit varying said annulus area to achieve a desired lifting effect, and moving means for moving one of said lift pipe outlet and said venturi relative to the other for varying said annulus area, wherein said lifting means includes a two-stage jet pump, a first stage positioned at a first elevation relative to the ocean floor, and a second stage positioned at a second elevation relative to the ocean floor, said second elevation spaced vertically from said first elevation, each of said stages including a fixed venturi and an inlet pipe extending thereinto, said inlet pipes each having an axially movable collar, said collar having an internal thread formed on an inner surface thereof and engageable with an external thread formed on an outer surface of said lift pipe, said collar including an external ring gear formed on an outer surface thereof, and said moving means including a drive means and a drive gear rotatably driven by said drive means, said drive gear engageable with said ring gear to rotate said collar to move it axially toward and away from said venturi, and settling tank means positioned between and in communication with said first and second stages of said two-stage jet pump.