Minerals Report - International Seabed Authority

environmental management is holistic, encompassing the direct impacts of
mining together with the management of waste.
DBM has progressed in understanding the nature and extent of
impacts since the initial studies to establish an environmental baseline.
This was an essential aspect in developing an understanding of the
company’s environmental impacts due to the paucity of detailed
information about the dynamics of the Benguela system. A key element
was to understand the system’s natural variability driven by large-scale
natural events that see low oxygen water introduced across the shelf on a
regular basis, with the introduction of large volumes of suspended
sediment from Orange River flood events providing an additional factor.
Without this, discrimination of local-scale mining impacts from the
influence of natural events would not be possible. Experience has proved
that conventional sampling techniques to determine impacts have inherent
difficulties. Many new insights have been derived from direct visual
observation using the Jago submersible, coupled with detailed analysis of
video material collected during submersible transects – a first for the
Benguela system.
This paper draws upon many contributions from studies
commissioned and aided by De Beers Marine to develop an environmental
baseline for the determination of impacts related to offshore diamond
mining on the southern continental shelf of Namibia and for the
continuous improvement of environmental management. As such, it
presents an overview based on the contribution of many different
scientists and staff of De Beers Marine. It is hoped that the paper will
contribute to the development of environmental management
philosophies for the deep-sea mining industry of the future.
1 Macro-Scale Ocean System Setting of Offshore Diamond Mining
in Southern Namibia
Offshore diamond mining operations occur on the inner and
middle continental shelf along the southwestern continental margin of
Africa [1], with Exclusive Prospecting Licenses awarded by the Namibian
Government extending to 2000 mbsl on the continental slope. The
Benguela Current strongly influences the continental shelf, which has long
been recognised as one of the world’s major upwelling regions and the site
of prolonged scientific study [2] since the Challenger and Discovery
Expeditions over a century ago. More recently, the ocean’s role in climate
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