Land-based diamond mining on the West Coast

Google Earth shows it best. The barren earth. Empty...as if a giant hand took a steel brush and just swept it over the surface of the earth...destroying everything. Plant and bush, quiver trees and lithops... gone! Millions of animals' habitats, where they had lived, found food and shelter, bred... just disappeared!

Diamonds may be a girls best friend, but the process of getting them - especially here in the Northern Cape - is everything but eco-friendly.

Driving past Alexcor and Trans Hex' diamond fields on ground level, you will probably not notice much of the devastation.  A few giant mine dumps, with smaller sand dumps nearby. Gates, fences, warning signs and booms prevent you from going too close. And although towns like Alexander Bay, Kleinzee and Koiingnaas are now more accessible for tourists, it certainly does not mean that you now have free reign to go where you want! The areas surrounding the towns are still restricted. The West Coast of South Africa is the biggest known economic source of alluvial diamonds in the world.  More than 90% of the diamonds recovered are of gem quality, having a colour, clarity and size most desired by consumers in the retail jewellery industry. Strict security is necessary for all diamond-mining operations, as the gems are easy to conceal and steal.

 One can feel almost guilty looking across the fence... I have no desire to go look for diamonds in those mine dumps, but the feeling of thousands of eyes watching you is quite unsettling! Your imagination will take its course... what is happening behind all those "closed doors" in the mining areas?

In 1908 the first diamonds were found at Kolmanskop, near Luderitz (Namibia). Thousands of gold diggers (must we change this expression?) flocked to the area to try their luck. This led to the subsequent discovery of the rich diamond deposits along what is now known as the Namibian coastline.  It was not until 1925 that the first diamond was discovered in Namaqualand on the Port Nolloth Reserve.  Shortly thereafter, concentrated prospecting operations began between the cliffs north of Port Nolloth and the Orange River estuary with only minor activity taking place to the south towards Kleinzee.  In 1926, the rich deposits at Alexander Bay were discovered.  These deposits proved so rich that in 1927 the Government prohibited all further diamond prospecting on state owned land in Namaqualand.  During this time prospecting operations at Kleinzee were laying the foundation for what was to become the De Beers Namaqualand Mines.  In 1928 the South African Government started mining operations at Alexander Bay.  Later diamonds were also discovered and mined elsewhere along the vast coastline.

But where do these diamonds come from?

Diamonds were originally formed at high temperatures and pressures at depths of 150-250 km below the earth`s surface.  These diamonds were brought to the surface by volcanic eruptions.  The resulting geological features are known as diamondiferous kimberlite pipes and are concentrated in the interior of the country.  Over time the top layers of the kimberlite pipes were eroded away and transported by the Orange River and its tributaries to the coast.  Here the soft light material was destroyed and removed by wave action, in the process concentrating the heavier and harder material such as diamonds, on the beach terraces.  In the past the sea level has retreated and advanced several times during global cooling or warming.  At various times, it was as much as 500m lower and 200m higher than it is today.  For this reason diamonds can be found both on land, buried in the sands of the ancient beaches, and underwater, in the sediments of the continental shelf.

Diamond mining concessions cover much of the coastal land between Olifantsrivier in the south and Luderitz in the North, and access is restricted to these areas because of security considerations.  The mining involves removing tons of sand and calcrete, known as overburden, to reach the underlying diamond-bearing gravel.  The overburden, which is up to 35m deep, is removed using draglines, giant scrapers and bulldozers, and is then dumped in areas that have already been worked.  Sometimes the diamond bearing gravel is locked up in concrete-like conglomerates, requiring drilling and blasting.  The remaining bedrock is then cleared and meticulously swept by hand.  Some of the richest concentrations of gems lie in gullies and potholes where the machines cannot reach.

In the recovery plant, the gravel is crushed and scrubbed to remove sand and clay, after which the material is passed through a dense media separation process, where the gravel and diamonds sink out.  Magnetic separation is then used to separate magnetic gravels from the non-magnetic diamonds.  This is followed by X-ray separation to isolate diamonds from the accompanying minerals.  During this process, the diamond fluoresces as it passes under the x-ray beam, and an air-operated ejector deflects it from the main stream of gravel.  The final sorting is done by hand.

It must be recognised that mineral extraction by its very nature has the potential to impact the environment unless carefully managed. The key challenge is Land Disturbance.  Diamond mining uses a variety of methods, some of which involve the removal of large quantities of soil from the earth.  However one must remember that it is economically beneficial to recover the greatest amount of diamonds while moving the least amount of other material. Therefore diamond mines seek to have the minimum sized footprint, and move only that necessary material (known as waste) efficiently. 

To restore the environmental impact of onshore mining the back-dumped overburden is covered with topsoil, which contains the seeds of desert plants.  The seeds germinate and grow to rehabilitate the devastated area.  Whistling rats assist in the rehabilitation process of old dumps by dispersing the seeds in their burrows and fertilizing the plants with their droppings.

Opencast mining is anything but beautiful. There is no denying this fact. Google Earth's satellite pictures tell the true story! But there is - like always - another side of the coin.  Alexcor's territory stretches from Alexander Bay to Port Nolloth. About 90km in length as the crow flies, and kilometers wide as well.  And, contrary to the common opinion, large parts of these areas are intact. It lies before you like a scenic nature reserve, protected against any and all human activities.  Pristine Strandveld Succulent Karoo. This is also thanks to the mining activities taking place further down the road. Here sheep haven't been grazing and trampling everything like on so many neighbouring farms!

Over the years diamond mines have offered work opportunities and jobs to thousands of South Africans - literally food on the tables! A lot has been done in the form of community development projects, empowerment and sustainability in the mining areas.  Infrastructure in the areas has been updated. Also important to remember is the fact that although diamond production in South Africa has dropped from 15 776 000 carats (2005) to 8 450 000 carats (2016), it still is a large contributor to our country's GDP.

Diamonds are forever, but diamond mines are not.  Old worked out mines are filled up and everywhere one can see the signs of Alexcor's rehabilitation programs. We have good hope... even if it is going to take a while!