Polymetallic Sulphide

A polymetallic sulphide, also called a seafloor massive sulphide (SMS), is a metal-sulphide deposit that forms at hydrothermal vents where seawater circulates through hot ocean crust and precipitates metals as it discharges through chimneys at temperatures up to about 400 degrees Celsius. The deposits are rich in copper, zinc, iron, silver, and gold and sit along mid-ocean ridges, back-arc basins, and volcanic arcs, commonly near 2,000 meters depth on mid-ocean ridges. SMS is one of the three deep-sea mineral resource types under International Seabed Authority jurisdiction in the Area. Active vents host chemosynthetic ecosystems found nowhere else, so mining inactive deposits is favored, and the ISA exploitation Mining Code is still being negotiated.