A Novel Mining Approach for Seafloor Massive Sulfide Deposits

Abstract

Sulfidic polymetallic ore deposits, known as seafloor massive sulfides (SMS) occur on the seabed as precipitation products from hot hydrothermal solutions as a result of mixing with cold seawater and are usually found at depths between 1,500 and 4,100 m. These deposits are formed basically in tectonically active spreading zones of oceans (mid-ocean ridges and "back-arc" spreading systems) and are the result of the global heat transfer from the mantle above the oceanic crust into the water column. In these SMS deposits, metals such as copper (Cu), zinc (Zn) and lead (Pb) as well as trace elements of silver (Ag), gold (Au) and rare antimony (Sb), cadmium (Cd), gallium (Ga), germanium (Ge), and indium (In) are present. This paper describes a novel technology for mining SMS deposits based on the vertical cutting approach developed by a joint research between BAUER Maschinen GmbH and Technip. A hyperbaric mathematical cutting model has been used to calculate the forces needed to excavate SMS deposits in water depth up to 2,000m. The model shows that in hyperbaric conditions, what influences the cutting energy is the water column rather than the geomechanical properties of the rock. Based on the mathematical model a preliminary cutting tool design is shown.

Transitioning to Sustainable Life below Water

“…From there, it will be pumped to the seafloor, cleaned from sediment onboard a mining vessel and then transported to shore for further metallurgical processing (SPC 2013c). More recently, the use of vertical cutter systems has been suggested (Spagnoli et al 2016).…”

Mechanical Tests and Numerical Simulations for Mining Seafloor Massive Sulfides

“…The SMS are distributed in the depth range of 1500-3600 m under the sea water [30,31], and the high confining pressure of its surroundings is different from that in the air. Under the condition of high hydrostatic pressure, the rocks are in the high-pressure state of three-dimensional stress, and a ductile cutting process usually occurs in the rock fracture [19,30,32]. In this section, PFC3D program was used to simulate the TCS tests.…”

Study on Cutting-Load Characteristics of Collecting Cutter for Seafloor Massive Sulfide

“…Submarine mining machinery is critical to mining efficiency and mining system safety. Based on the trench cutter technology, Bauer Maschinen Gmbh and Technip jointly worked on vertical cutter tool, which is adapted to harsh subsea conditions [5][6][7][8]. With its experience in the dredging and offshore mining industry, the Royal IHC has proposed a design concept for deep sea operations (Fig.…”