Rocks from hydrothermal vents can spontaneously combust, posing potential risks for deep-sea mining operations

Projects involving the mining of seafloor massive sulfide (SMS) deposits around hydrothermal vents already face criticism over their destructive nature, and now these projects may face a new concern: spontaneous combustion. A new study, published in Scientific Reports, describes how certain samples of rock brought up from SMS deposits have unexpectedly caught fire. The study indicates that conditions at the surface, combined with processing activities, may turn some of these rocks into a hazard.