26 June 2020
Coffer dam mining operations in 2017. All images from the report Amendment of Environmental Management Programmes for Mining Rights 554MRC, 10025MR, 512MRC and 513MRC - Volume 2: Mining Right 554MRC, November 2017 by SLR Consulting in association with Placer Resource Management
The use of coffer dams in beach mining for diamonds on the Namaqualand coastline has raised serious environmental question marks for decades. More recently, it has sparked a feud between diamond miners from different camps amid allegations of intimidation and the creation of a climate of fear.
After years of complaints to various authorities – the most recent to environment minister Barbara Creecy last month – environmental inspectors known as the “Green Scorpions” from the Department of Environment, Forestry and Fisheries have launched a formal investigation into allegations that this controversial mining technique is being used illegally in extracting a share of the region’s rich mineral wealth.
The probe may result in criminal charges being laid.
Coffer dams are temporary sea walls constructed to hold back the ocean from the intertidal beach area and shallow surf zones while miners access the diamond-bearing gravels that underlie the beach.
They’ve been used on Namaqualand’s “diamond coast” since the 1950s, and are considered to be an efficient mining method for accessing diamondiferous gravels located below the high-water mark and in the shallow surf zone. However, while originally constructed from beach sand and adjacent coastal dune material, sea walls are now routinely armoured with gravel, rocks and boulders, with much of this material quarried onshore.
The legality and impact of this current practice of introducing land-originated or “non-native” material into the marine environment lies at the heart of the coffer dam controversy, along with major concern about the rehabilitation – or non-rehabilitation – of coffer dams once mining has ended.
Diamond mining at Alexander Bay began after the proclamation of the State Alluvial Diggings in 1928, and state-owned diamond mining company Alexkor emerged in 1992 from the earlier 1989 Alexander Bay Development Corporation.
In the early 1990s, the Council for Scientific and Industrial Research (CSIR) was commissioned by Alexkor to undertake a specialist study of issues and impacts of marine mining as the basis for an Environmental Management Programme for its mines. The CSIR’s resulting 1994 report was unequivocal: “Under no circumstances should gravel, cobbles or boulders be used in coffer dam mining operations” – as had already been done by Alexkor in one of its mining blocks.
Following this strong statement, the use of coffer dams was abandoned for nearly two decades, then resumed on a limited scale from about 2012 and initially without rock-armouring.
But because of the high cost associated with building and maintaining extensive sand seawalls, the practice of rock-armouring the sea walls with land-quarried material was introduced the following year.
One of the issues likely to be probed by the Green Scorpions is whether such armouring constitutes illegal dumping at sea and should therefore require a special permit, as required by environmental legislation like the Integrated Coastal Management Act and associated Dumping at Sea regulations.
There are claims that while the use of gravel, rocks and boulders may have been legally approved for coffer dam construction, the current practice of packing these materials into the seawalls with vast quantities of fine debris and matter from the quarrying process is definitely not legally sanctioned. And this fine material is allegedly causing significant environmental damage because it’s phytotoxic (poisonous to plant life) and “sterilises” adjacent shallow-water diamond-bearing areas, as well as introducing large plumes of heavy mineral contamination that reduce visibility and make recovery of gemstones by shallow-water diving operations significantly more challenging or even impossible.
Other issues of serious environmental concern about coffer dams past and present relate to the scale of operations – some coffer dams have extended 250-300m into the sea – and the dams’ potential for long-term and possibly permanent alteration of local beach profiles, local biodiversity, bathymetry, near-shore sea currents, and associated estuary and wetland functioning.
The Scorpions are also understood to be looking at possible contraventions of sections of the National Environmental Management Act (NEMA) relating to any acts or omissions that “unlawfully and intentionally or negligently” cause significant pollution, degradation of the environment, or detrimentally affect the environment.
An illustration of sequential coffer dam construction
So depending on who you talk to in the industry, coffer dams are one of two things.
According to some miners, they are vital tools in the continued extraction of Namaqualand’s once fabulously rich but now much less easily accessible diamond resources, and as such are one of a few crucial economic props still sustaining a poverty-stricken region with a massive unemployment rate.
Others, however, argue that coffer dams, depending on how they’re constructed, are an environmental disaster. They describe the coffer dams as illegal constructions that have devastated, and continue to devastate, large swathes of coastline, resulting in fewer employment opportunities, economic hardship and damage to biodiversity.
A linked issue is the rehabilitation, or lack of rehabilitation, of previously mined areas where coffer dams were used, and funding for future rehabilitation that some argue is woefully inadequate.
For example, the 2,000 hectare Orange River Mouth (now the Gariep river) was one of South Africa’s early Ramsar Wetlands of International Importance, declared under the Ramsar Convention in June 1991. This estuary wetland is immediately adjacent to diamond mining concession Block 60 of state-owned diamond mining company Alexkor, where coffer dams have been used.
However, just over four years after its declaration, this wetland site was assigned to the Ramsar Convention’s “wall of shame” – the Montreux Record of wetlands that have changed their ecological character because of human interference – where it is still listed.
“Following the collapse of the saltmarsh component of the estuary, the site was placed on the Montreux Record in 1995. The rapid degradation was the result of adjacent diamond mining activities and flow regulation of the Orange River as a result of dam construction,” the convention’s website states.
Last month, environmental inspectors from the Department of Environment, Forestry and Fisheries (DEFF) spent two days in the mining town of Alexander Bay at the mouth of the Orange/Gariep River.
They were responding to complaints that environmental legislation was being flouted in beach mining operations – specifically in the use of coffer dams – on diamond concessions in the northern section of South Africa’s coastline up to the Namibian border.
DEFF spokesperson Albi Modise confirmed that the four-person team had included wetland specialists and was investigating two companies for alleged contraventions of the National Environmental Management Act (Nema) and the Integrated Coastal Management Act (ICMA).
He declined to name either the companies or the complainants and refused to say whether the team had found anything of concern during their visit. He said their findings were still being assessed and that “the outcome of the current investigation will determine if other areas will be investigated”.
The Department of Mineral and Energy Resources had been consulted about the investigation, Modise added.
Although Modise did not confirm this, GroundUp understands that a follow-up visit by the Green Scorpions to Alexander Bay is likely and that criminal charges may follow.
Although not officially confirmed, it’s a safe bet that the obvious target of the Green Scorpions’ investigation is Alexkor or, more correctly, the Alexkor Richtersveld Mining Company Pooling and Sharing Joint Venture (PSJV) formed between the government-owned entity and the Richtersveld community after they had won a huge land restitution claim that included land-based mining rights in 2007.
The joint venture, in which Alexkor has a 51% interest and the community 49%, manages marine and land diamond mining in five huge blocks extending roughly between the mouth of the Orange/Gariep River in the north and to a point close to the little mining town of Kleinzee in the south. It does not mine itself but conducts operations through more than 100 mostly small private contractors, and is the largest employer and diamond operator in the region.
Both Alexkor and the PSJV, which is not a constituted company, have been rocked by administrative chaos and allegations of corruption recently, and last year Alexkor was placed under administration.
In his Final Handover Report of February this year, Alexkor administrator Lloyd McPatie reported that both entities were in a “precarious” financial position and the mine was “technically insolvent”. However, although the PSJV’s diamond resources had been extensively exploited over decades, both at sea and on land, a “substantial resource base” was believed to remain, he added.
The PSJV’s coffer dams are currently operated in terms of revised Environmental Management Programmes (EMPs) that were approved by the Department of Mineral Resources and Energy in December 2018.
The revision process was aimed at bringing the joint venture’s mining operations in line with current requirements of the National Environmental Management Act, amended Environmental Impact Assessment regulations of 2014, and “to ensure alignment with each other, all new legislation, environmental standards, as well as internal PSJV Performance Assessment Reports”.
The environmental experts who conducted the revision process in 2017/18 state in their November 2017 report that constructing coffer dams “effectively smothers and eliminates any supratidal, intertidal and subtidal biota in the footprint of the coffer dam” and that “the deposition of large volumes of non-native rock during sea wall construction may result in the physical alteration of the shoreline to an extent that cannot be remediated by swell action”.
“In extreme cases, where the coffer dam wall material is not completely removed, stretches of sandy beach could be permanently transformed.
“The impacts associated with the disturbance of intertidal and shallow subtidal habitats by coffer dam operations are considered to be of high and very high significance of sandy and rocky habitats …
“However, with [mitigation], the impact could be reduced to high and medium significance for both rocky and sandy habitats, respectively.”
They recommended a series of mitigation measures for coffer dam operations that were incorporated as conditions of the final approval issued by the Department of Mineral Resources and Energy.
These included that materials sourced locally from old tailings dumps and existing sea walls should be used for coffer dam construction, and that quarried material should be avoided “where possible”.
Also, the use of quarried rock and disturbances to sensitive coastal habitats should be “minimised”; the number of coffer dams concurrently operational should also be minimised; and each block should be sequentially mined to completion, with only two adjacent blocks active concurrently.
All coastal excavations should be backfilled with the excavated material as mining progressed, “in such a way as to maintain the original beach profile as far as possible”.
Giving reasons for its decision, the Department of Mineral Resources and Energy said the environmental impacts of the beach mining would be addressed by the consultants’ proposed mitigation measures that would be incorporated into the approval.
“The Environmental Management Programme report sufficiently provides for avoidance, management and mitigation of environmental impacts … also, the suggested mitigation measures stipulated by the specialists and the state organisations are realistic,” the Department stated.
Its conditions of approval included:
Alexkor did not respond to a request for comment.