Construction World September 2022

QUARRYING

The biggest challenge for Rooikraal Quarry is the depressed sales demand.

ROOIKRAAL QUARRY'S SENSITIVE USE OF WATER AfriSam’s Rooikraal Quarry is located near Brakpan, Gauteng and mines competent dolerite rock. The quarry is a big supplier to asphalt markets which it supplies with its sought-after products – especially 10 and 20 mm road stone. In the production of aggregate, sand and gravel used in roadbuilding, raw material is mined from a deposit of high-grade material that is intermixed with other undesirable materials and detritus. As asphalt cannot have aggregates with any particles, the aggregate must be washed to get rid of such materials. ConstructionWorld visited Rooikraal Quarry to learn about the closed circuit it has established to wash its products and which furthers AfriSam’s environmental credentials.

T he Rooikraal Quarry has a Life of Mine of 240 years. “The property itself is large and only two portions are used for quarrying purposes. These consist of two adjacent pits – one for dolerite mining and one for dolomite mining. “Before AfriSam acquired the quarry in 2001, dolomite was being mined, but it is mining dolerite now,” says Zielas du Preez, AfriSam’s Regional Manager - Gauteng and Western Cape

Operations. “The historical dolomite pit is used a tailings catchment facility for the quarry’s recycling process and the tailings produced from the washing process are pumped into it.” Louis Sterley, Rooikraal’s Works Manager explains the reason for the change from dolomite to dolerite. “Although dolomite has excellent cementitious properties and a

36 CONSTRUCTION WORLD SEPTEMBER 2022