The mined-out bedrock pit of a diamond mine in the Northern Cape has a new lease on life. Filled with seawater, the pit has been turned into a dam that teems with oysters. Brightly coloured floats bob on the water, forming a stark contrast to the barren, sandy landscape that surrounds the area. They hold the oyster baskets in which the molluscs are grown to the correct size before being sold to distributors in Namibia and SA.

Tom Tweedy, head of communications at De Beers corporate headquarters in Johannesburg, says: ‘The mariculture project began in 2001 at De Beers’ Namaqualand mines and has matured into a viable oyster-rearing business still operating today. This is a private initiative with some seed funding a decade or so ago from De Beers.’

The onshore oyster farm in Kleinzee is a successful example of how old mine pits and their infrastructure can be converted for different commercial use, which provide an income to former mine employees. One of the key goals of mine closure planning is to enable local mining communities to find alternative livelihoods once operations have ceased. They should no longer be dependent on the mining company when it pulls out of the area.

Alistair Joshua, production manager at Kleinzee Mariculture told eNCA news channel in August 2013: ‘The target is getting approximately 12 million 14 mm seed oysters out annually. This excludes the other sizes we also hope to do. We’re getting a sorting machine soon, and after that we can only go forward. We won’t be looking back at all.’

Kleinzee is a previously ‘closed’ mining town owned by De Beers that was proclaimed a public town and handed over to the local municipality in March 2012. The company invested about R90 million in Kleinzee and another town, Koingnaas, to ensure they would not become financial burdens for their respective municipalities.

An enterprise development hub and proposed wind farm to generate clean energy are expected to boost the local economy and create much needed jobs.

In Kleinzee old mine pumps were converted to reticulate seawater for the oyster farming enterprise. De Beers has also set up a small-scale abalone farm that employs local people who grow the sought-after delicacy in tanks.

One of the key goals is to enable local mining communities to find alternative livelihoods once operations have ceased

It has been suggested that other species including mussels, and fish such as kabeljou and the fast-growing tilapia, could be farmed in the intertidal mining pits of the Northern Cape.

Further inland, Harmony Gold is finalising an agriproduction feasibility study on ‘aquaculture and some downstream processing activities, which may include [but are not limited to] packaging and canning activities’. Spokesperson Marian van der Walt says: ‘Harmony aspires to convert the land capability from mining to other value-creating capabilities that are congruent with national socio-economic and environmental imperatives, such as job creation, poverty alleviation and green energy production.’

The company participated in a housing project in Welkom where six men’s hostels of the decommissioned Masimong gold mine have been turned into a total of 486 low-cost family apartments. The project involved 12 local companies and created 3 000 jobs.

This type of sustainable development of ex-mining communities is a relatively new concept in SA – just like the compulsory financial provision that is now required upfront for the rehabilitation of closed mines. In the early days the focus lay solely on extraction and profit.

Many miners did not take environmental impact into account, thereby leaving a harmful legacy that includes acid mine drainage, surface and groundwater pollution, soil and vegetation degradation and tainted air quality.

Owners who can be located are still held liable for the rehabilitation of their old mines. However, in SA alone there are nearly 6 000 derelict and ownerless mines that have become the responsibility of the national Department of Mineral Resources (DMR). A 10-year, medium-term plan is in place to rehabilitate these derelict and ownerless mines, but the department predicts that this will in fact take until 2038. The plan, which is being implemented in three phases, is expected to cost about R1.4 billion.

In the financial year ending 31 March 2013, the DMR rehabilitated 13 mine sites, treating derelict asbestos mines as a priority because of their ‘extreme danger’ to the public.

The landscape regarding future rehabilitation was changed by the Minerals and Petroleum Resources Development Act of 2002 (MPRDA), a transformation milestone because it prescribed a cradle-to-grave approach. A mining company now has to develop a holistic environmental management plan that includes a detailed closure plan and in which dedicated funds are set aside (usually a bank guarantee or trust) to cover the rehabilitation process.

A company is legally required to rehabilitate the affected post-mining environment ‘to its natural or predetermined state, or to a land use that conforms to the generally accepted principle of sustainable development’. The mining right holder remains responsible for any environmental liabilities until the DMR has issued a closure certificate.

Forward-thinking mining houses implement concurrent rehabilitation throughout the life of their mines to reduce the risks and liability at the time of closure. The Anglo American group has developed a mine closure toolbox for more efficient, cost-effective rehabilitation.

Hulisani Rasivhaga, media specialist in the group’s corporate communication division, says: ‘Some of the mines we have closed in the past have since been divested. As part of the closure planning process, the end land use is determined and this differs for each mine, depending on the particular context.

‘An example is the Oaks mine in Limpopo, which was a diamond mine designed with the end in mind, and hence a good example of successful full life cycle mine planning. Concurrent environmental rehabilitation was part of the mine’s design with waste rock and mineral residue being deposited to achieve the end-state during the life of mine.

‘In the closure phase, the focus was on ecological restoration and removal of remaining infrastructure, enabling the area to be considered for use in game ranching,’ she says.

Originally the area had been used for commercial beef production. However, there was a risk of damaging the rehabilitated land through overgrazing post-mining. It was decided to use the land for conservation and game farming instead.

In SA, several old mines have been preserved as historical sites or museums. The entire town of Pilgrim’s Rest in Mpumalanga is a national monument that recreates the early gold rush days. Another popular tourist destination is Gold Reef City, the Johannesburg theme park that combines history with adventure rides. Visitors can descend a 215m mine shaft to experience gold extraction.

Plans are under way to upgrade George Harrison Park, the site of the first discovery of gold in the Witwatersrand Main Reef. The old mine infrastructure is still visible in the park, but closed to the public for safety reasons.

Kimberley’s Big Hole, the country’s first diamond mine that operated between 1871 and 1914, is reportedly the world’s largest excavation dug by hand. It hosts an interactive museum that features a diamond vault, an underground mine experience and the ‘old town’ – a collection of historic Kimberley buildings and shops that have been brought back to life.

Previously, a disused tunnel at the Big Hole served to cultivate mushrooms. De Beers’ Tweedy says: ‘The oyster mushrooms were grown and harvested for a few years. However, there were challenges and considerable investment in attempts to regulate temperatures and humidity. Seasonal changes and difficulties in consistent conditions – such as exist in regular mushroom farms, as well as the cost to get the produce to large consumer markets, eventually led to the closure of the project.’

Cape Point Vineyards is another example of innovative, successful land use. Investment banker Sybrand van der Spuy arrived in Noordhoek on the Cape Peninsula, as a co-owner of a kaolin mine – the clay used in the production of, amongst other things, paper and porcelain. He established an award-winning vineyard on derelict ground next to the mine in 1996 and there have been reports of a possible retirement village to be built on the former kaolin mining land near Chapman’s Peak.

However, it’s often not possible to restore the land to its pre-mined state. Green energy projects, such as the wind farm planned by De Beers, could be the way to go. Harmony Gold is considering a bioenergy production from crops (mainly sugar beet), cultivated on reclaimed mine land.

Mine rehabilitation generally involves a compromise between environmental rehabilitation as well as socio-economic development. This can be seen in the case of the Kleinzee oyster farming initiative. Here, the new land use has thrown an economic lifeline to the dwindling community in the area.

By Silke Colquhoun
Image: Fredrick Broden/reneerhyner.com