Diamonds have provided an economic lifeline to Namibia for many decades. Environmental Manager of De Beers Marine Namibia, André Goosen, who has a marine biological background and completed a Masters degree in Zoology at the University of Port Elizabeth in South Africa, explains the steps that have been taken to tread lightly in rough waters.
Marine diamond mining started in 1961 and expanded rapidly off southern Namibia’s coast in the mid-1980s. Deep-water mining (deeper than 80 m) started in 1990, and has continued to expand into deeper waters as the required technology was developed. Currently, mining operations occur at 100 – 130 m water depth at distances of 20 to 40 km from the shore off the south-western coast of Namibia. Purpose-built vessels employing sub-sea drill technology mine the unconsolidated superficial sediments from the seabed. Each mining vessel is effectively a mine, where the diamond recovery involves the crushing and screening of seabed sediments in a non-hazardous process.
At present, De Beers Marine Namibia conducts diamond mining and exploration on behalf of Namdeb Diamond Corporation in Namibia. This process of exploration and mining has been exciting and challenging, both technologically and environmentally. The area of mining falls within the Benguela Upwelling system, a biologically productive system that supports valuable commercial fisheries. The potential consequences of mining on the dynamics of the ecosystem must therefore be carefully considered. While land-based mines conduct rehabilitation programmes after mining, in the marine environment rehabilitation occurs through natural processes. De Beers Marine Namibia has therefore invested in research to understand the impacts of its mining activities, leading the industry in this regard. The focus of environmental research is to increase knowledge of the natural variability of the environment, understand the consequences of marine mining, monitor changes over time and minimise impacts.
In 1991, De Beers Marine (South Africa) commissioned an Environmental Impact Assessment (EIA) – the first of its kind – of its mining operations in deep-water areas off southern Namibia. In 1996, after years of surveys and sampling, the multi-disciplinary team of independent scientists concluded that offshore mining operations do not have a significant effect on the environment. Amongst others, the study investigated two key impacts. The first is that the discharge of tailings, as well as the action of the mining tool, causes a mixing of the sediment layers on the seabed, which is home to a multitude of species, most of which are too small to see clearly with the naked eye. Studies showed that the operation has a very localised negative impact on hard- and soft-bottom communities, with mined areas taking approximately four to eight years to recover. The second impact results from the discharge of sediment from mining vessels, creating a plume of suspended fine-grained sediment that is visible on the water surface. The sediment contains no toxic substances. Specialists have investigated many facets regarding the potential consequences of tailings plumes, in particular the effect that they may have on reducing oxygen levels in the water column.
Since deepwater mining began, 19 km2 of seabed has been mined at a current rate of about 3 km2 per year. However, the total area impacted by both mining tool disturbance and tailings plume settlement in deepwater areas since 1991 is estimated to be approximately 50 km2. Within the mining area, relatively few fish species occur naturally, there are no major fish spawning grounds and currently no commercial fishing activity. Rock lobster forms the basis of an important fishery in southern Namibia but mining operations at present do not overlap with optimal lobster habitat or any lobster fishing activities.
A precautionary approach has been adopted and long-term joint research and monitoring projects with the Namibian Ministry of Fisheries of Marine Resources (MFMR) has been initiated, in order to adequately address issues of concern. The mutually beneficial relationship between De Beers Marine Namibia and MFMR has highlighted the value and importance of partnerships between industry and academic and research institutions in Southern Africa. De Beers Marine Namibia benefits by ensuring that its environmental impact research is innovative and scientifically rigorous and our partners benefit by the provision of opportunities for researchers and students to work on projects to enhance the understanding of the marine environment.
Although well-designed environment monitoring programmes are a necessary component of any marine mining project, an increased understanding of the influence of natural disturbances is required to critically assess the combined effects of all mining operations along the coast. Natural disturbance occurs as a result of seasonal or periodic environmental variations when animal habitats are influenced by factors such as currents, oxygen concentration and the settlement of sediments suspended by storms and strong winds. Up-welling and sulphur eruption events are also regular occurrences along the Namibian south coast that often cause stressful conditions for animals. Organisms associated with these environments have to adapt to ever-changing conditions in order to survive.
Although seabed impacts are the key impact, De Beers Marine Namibia does not focus only on this aspect of environmental management. Through the implementation of an Environmental Management System certified to the international standard, ISO 14001, all aspects of the company’s operations are carefully considered and managed in pursuance of the highest levels of environmental management. The award of an ISO 14001 certificate is not a once-off process, with surveillance audits conducted every year by the certification body to assess maintenance and adherence of the standard. Retaining the ISO 14001 certificate will require maintenance of the Environmental Management System and a commitment by all employees to continual environmental improvement.
The philosophy of the company, as embodied in the company’s Environmental Policy, is to continuously improve its environmental management practices through monitoring of the key characteristics of operations, thereby reducing negative im-pacts resulting from operations. Several elements must be dealt with to ensure a functional system aimed at ensuring continual improvement (a key aspect of ISO 14001). These include a company environmental policy, designated responsibilities, legal compliance, adequate communication and training, impact assessments, management plans, procedures, environmental objectives, a corrective action system, environmental auditing and management review. The remote nature of operations means that the environmental team relies on satellite communications and the use of an Intranet-based EMS. This enables access from each location to all documentation from procedures to current audit reports, as well as environmental awareness information.
De Beers Marine Namibia’s mining is only one of a number of operations along the Southern African coastline and rapid advances in marine-mining technology are enabling more operators to access previously inaccessible areas. A potential increase in mining activity by all mining operators in the future may have a more significant cumulative effect on the ecosystem. For this reason, in addition to the implementation of well-designed environmental monitoring programmes and the ongoing im-provement of our environmental management system, De Beers Marine Namibia continues to drive and participate in research efforts and strives to remain the leader in this marine field in Africa.
This article appeared in the 2003/4 edition of Conservation and the Environment in Namibia.
Last Updated on by