ABSTRACT
Manganese nodules and crusts represent an ocean mineral resource that will likely be developed during the course of the 21st century. Recent environmental work on manganese crusts has shown that 75% of the environmental problems associated with marine ferromanganese operations will be with the processing phase of the operation, particularly the disposal of the waste material, the tailings. Traditionally, mine tailings are dumped in a tailings pond and left there. Current work with manganese tailings has shown them to be a resource of considerable value in their own right. Tailings have applications in a range of building materials as well as in agriculture. This paper will review the ways in which tailings are disposed of and the potential alternate uses of these tailings. They are a useful additive as fine-grained aggregate in concrete, to which they impart higher compressive strength, greater density, and reduced porosity. The manganese appears to have some anti-biofouling capabilities. The tailings serve as an excellent filler for certain classes of resin cast solid surfaces, tiles, asphalt, rubber, and plastics. The tailings also have applications in coatings and ceramics. Two-year agricultural experiments have documented that tailings mixed into the soil can significantly stimulate the growth of Hawaiian Koa trees. The effect of using mineral tailings for secondary applications enhances the profitability of marine mining operations by a small but important margin.
