Quarry Southern Africa November 2018 - Page 21

WINNING NPC Sterkspruit Aggregate supplies a wide variety of local clients such as block yards, asphalt plants, hardware shops and precast concrete manufacturers. Its business depends to a large degree on local road projects in the surrounding area. material as possible. Thereafter the drilling contractors come in and they will drill the bench according to pattern and depths we have agreed upon. They then come and charge up the drill holes and set off the blast. The excavators and dumpers remove all the blasted material to the crushing plant where it’s broken down to the different aggregate sizes we require,” explains Mandass. For the high walls, the company’s code of practice dictates its walls be kept to a maximum height of 15m and minimum bench width of 20m. “Adhering to the code of practice is a challenge due to nature of our deposit,” says Mandass. From this process, Sterkspruit produces aggregates in the form of concrete stone 26.5mm down to 6.7 mm; crusher dust; as well as of base course from G1 to G7. The tonnage produced at the quarry is closely aligned to sales rather than actual capacity – the higher the sales, the higher the tonnage processed. “We supply a wide variety of local clients such as block yards, asphalt plants, hardware shops and precast concrete manufacturers. We also depend on to quite a large extent on local road projects in the surrounding area.” Little of the product is beneficiated at the plant, with the one exception being the washing of the crusher sand. “The one advantage of the product from the NPC Sterkspruit Aggregate quarry is the beautiful colour of the quartzite,” says Avin. Operations on the quarry are highly efficient, with one load cycle of aggregate “If you were to time it I believe would take about 15 minutes from the time rock it was tipped into the primary crusher hopper until it ends up as product.” Quartzite requires rugged equipment Crushers and screens are supplied by a combination of mainly Osborne and Metso, all long established suppliers in the industry. “The Dezzi equipment we have was “We monitor and benchmark our electricity usage against our sister quarries in South Africa and elsewhere in the world, so that if any of them are controlling their electricity consumption better than us then we can learn from and follow their example.” Quartzite’s soundness and abrasion resistance are superior to most other materials, making it a superior construction material. www.quarryonline.co.za  QUARRY SA | NOVEMBER/DECEMBER 2018_21