Posted on December 8, 2016
Chatham Rock Phosphate and its Dutch technical partners Boskalis and Deltares have received Dutch government research funding to improve the environmental management of marine mining. This co-funding has been awarded by The Netherlands based Topsector Water TKI Delta technology.
The increased global interest in the economic and environmental outcomes of marine mining for resources such as phosphate, manganese nodules and polymetallic sulphides has highlighted the need to develop tools and methods to predict, adaptively manage and reduce the environmental effects of marine mining.
Lack of field observations
Adapting computer-modelling tools to predict plume dispersion for deep-sea mining (or dredging) operations is hampered by a lack of field observations in these environments.
It is possible to validate hydrodynamic and sediment resuspension models by deploying sensors for field observations over several months. Validating the predicted sediment plume dispersion is much more difficult as it requires a large-scale source of suspended material in the water such as trial mining. Trial mining requires an environmental permit, which usually requires knowledge of the sediment plume behaviour.
The research project will investigate the behaviour of re-deposited material using a combination of state of the art laboratory analyses and computer modelling to assess both the plume dispersion and the continuous process of settling, deposition and bed formation of sand and silt. The results will reduce the uncertainties regarding predicting re-suspension and dispersion of the material being returned to the seabed.
Ways to adaptively manage re-deposited sand and silt
This jointly developed project will make computer models of plume dispersion more realistic and will look at ways to adaptively manage re-deposited sand and silt in deep water. Additionally, the project will investigate the use of flocculants, natural materials that can be added to the returned sand and silt to make the sediment plume settle from the water more quickly. This may be the first time flocculants have been considered for deep water mining or dredging
Public-private partnerships
The Dutch Ministry for Economic Affairs stimulates public-private partnerships between research organizations and companies in the Topsector Water TKI Delta technology by allocating and awarding funds to reviewed high quality research proposals. Deltares is an independent institute for applied research in the field of water, subsurface and infrastructure, and Boskalis is a marine services company. Chatham Rock Phosphate intends to apply for a marine consent to extract rock phosphate from the seabed on the Chatham Rise, east of New Zealand.
The results are being developed using the vast amount of data already available for the Chatham Rise marine mining project, but will have direct relevance to all projects in the offshore mining and dredging industry .
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