Environment

Environmental concerns about deep-sea mining increased substantially during the last two decades of the twentieth century. These were primarily related to manganese nodule mining and were mainly concerned with the destruction of deep-sea life, the development of sediment plumes, and the effect on the water column of the raising of sediment and nodules. A number of experiments were carried out to investigate the effects of these activities. Environmental studies related to PMS mining were only carried out in the Red Sea, and were deemed inadequate to fully evaluate the effects of mining the deposits there.