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Setting the record straight on alleged coal mining at Rietvlei clay quarry

Corobrik Rietvlei Quarry

Corobrik Quarry, Rietvlei

The best solution for the long-term sustainability of leading brickmaker Corobrik’s clay quarry adjacent to the ecologically sensitive Rietvlei Nature Reserve in Centurion is to ensure the successful removal of the coal deposits that have been discovered.

“Bear in mind that that there is already an established coal mining operation in the area. We have operated our Rietvlei quarry, mining brickmaking clay, sustainably for 40 years due to our successful mitigation measures,” comments Corobrik CEO Nick Booth.

He adds that the discovery of coal has required some small adjustments to Corobrik’s environmental planning or mitigation measures at its clay quarry. “In terms of the responsible way we mine, it does not affect our planning or the manner in which we conduct our environmental mitigation, but the storage and removal of coal does require additional environmental controls” notes Booth.

The brickmaker mines three different types of clay at Rietvlei. Upon discovery of a small narrow coal seam, it applied to the Department of Minerals and Energy (DMRE) as early as 2022 to obtain a licence to mine the coal so as to remove it and secure ongoing access to the clay reserves present.

“All that has happened is because it is coal, the DMRE wants us to reapply for the permit and restate everything we have done in terms of our original mining licence,” says Booth. The challenge posed by normal coal mining, such as the operation near the Corobrik clay quarry, is that it involves boxcuts that strip swathes of land.

“In coal mining all the overlying layers are removed. Yes, the topsoil is placed on the side, but all the other layers are intermingled,” stresses Booth. “All coal deposits have clay overlayers, but not necessarily usable clay due to the nature of the coal deposits.” The stored material is ultimately used as a 'hodgepodge’ of a backfill material with a lot of waste coal in it.

“It is a lot less environment-friendly process from a sustainability perspective than what the operation we undertake in our clay quarries,” says Booth. “There are a number of issues around quarries from a sustainability or an environmental impact point of view. One is obviously to adhere to best practice, so you generate minimal waste.”

This involves drilling ahead of the quarry in order to understand the clay deposits and minimise the quantity of overburden that needs to be removed. Planning must also consider surface water collection, which involves trenching, containment and pumping.

“You have always got the water under control. There is no water leaving the site. The ultimate aim is to reuse that water in your processes, either as dust suppression or even back into your manufacturing processes to conserve this precious resource,” highlights Booth.

Another consideration is natural vegetation, but Corobrik is fortunate in that its clay quarries do not have an impact on the natural environment. “The reason I say that is most, if not all, our sites have been in operation for a long time and are pretty much established as mining sites,” says Booth.

Another environmental consideration is the presence of fossils, but here the clay is mostly shale and only contains basic plant-type material, if any. The biggest mitigation factor around clay quarrying is dust suppression, especially as clay is a very fine particle. “Dust suppression is absolutely critical in terms of not impacting the surrounding community,” says Booth.

“Those are really the only major impacts in terms of our clay quarries from a sustainability point of view. In the long term, you find office complexes and housing developments on rehabilitated quarry sites. You can never fill the hole completely, so you landscape accordingly, and because you are backfilling with old materials, it generally makes the land very usable from a building point of view,” says Booth.

However, there is the possibility of returning the site to agricultural use because the overburden and top soil are removed and stored separately. “When you carry out backfilling, the topsoil is returned with all its seeds present. What happens is the grasses come back very quickly as long as you have a decent rainy season. If you go into a drought, it can be challenging. Generally, the land recovers very quickly.”

Booth concludes: “From a sustainability point of view, clay is a very environment-friendly material to mine. It is not a mineral rock like platinum or gold that requires crushing and processing with its attendant chemical processes. We are simply using the natural clay for brickmaking. Brick is a sustainable building material and is well accepted as such. From a quarrying and sustainability point of view, it involves one of the greenest mining processes you can get.”

Corobrik CEO, Nick Booth

Nick Booth, CEO of Corobrik


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