Summary

Chatham Marine mining is an increasing business encouraged by the global demand of minerals. Though these deep sea mining activities leave literally a footprint on the ocean floor impacting sea life. Chatham Rock Phosphate (CRP) aims to be the premier supplier of direct application phosphate to the New Zealand and global agricultural sector, supporting sustainable farming and agricultural processes. To realize this objective phosphate will be mined at the 400 meter deep Chatham Rise, located in the SW South Pacific Ocean. At a ship the phosphate is separated from the tailings and a plume of tailings will be placed on the ocean floor at a depth of 400 m (see Figure 1). To avoid environmental issues the spreading of the plume has to be controlled. Chatham Rock Phosphate’s failure to get an environmental consent for marine mining in New Zealand is one example of the increasing global need to develop validated tools and methodologies to predict, adaptively manage and reduce the environmental effects of marine mining. Validation of (modelling) tools to predict and manage plume dispersion for deep sea mining (or dredging) operations is hampered by a general lack of field observations on the behavior of mine tailing plumes in deep to very deep water. Validation of hydrodynamics models, underlying sediment models, is feasible by executing long-term (months-year) field observations.

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