Particle Geochemistry of Hydrothermal Systems and Implications for Mining Seafloor Massive Sulfides

Seafloor massive sulfide deposits form due to high-temperature hydrothermal venting that occurs globally, in every ocean basin, along plate boundaries and intra-plate hotspots. At these sites, the rapid mixing of hot, metal- and sulfur-rich reduced fluids into cold, oxygenated ocean water results in abundant mineral precipitation. The mining of seafloor massive sulfides is likely to occur in the near future and will generate a new class of mainly inorganic particulates, different from those formed in hydrothermal `black smoke.' While the major components of both black smoke & SMS tailings are Cu, Fe and Zn sulfides, many other minerals, including those containing technology critical elements, especially tellurium, are present. A comparison of these two classes of particulates will be presented, including chemical composition and reactivity to oxidative dissolution.