Modern Quarrying July-August 2017

ON THE COVER

about six to seven years on a set of liners where some aggregate producers are for- tunate if they can get six weeks use from their liners. “From the primary crusher, everything is stockpiled depending on the source, whether it is limestone or dolomite,”he says. Aggregate is sold from the primary stockpiles and we feed the secondary pro- cess plants from the other stockpiles. “High grade dolomite is crushed and screened in the secondary plant utilising HSI crushers down to -1,0 mm. The same applies for the limestone which goes through the secondary limestone process plant where we reduce it to two sizes: -1,0 mm which goes to the glass industry, and 1,0-6,0 mm which is fed to the fluid bed calciner kiln. We draw off some ultrafines from the -1,0 mm fraction with an air classifier to supply cli- ents in the effluent treatment industry. The limestone is fed to the kiln and calcined at roughly 900 o to convert the calcium carbon- ate (CaCO 3 ) to calcium oxide (CaO). “Some of the calcium oxide is sold as quick lime with the majority being hydrated. It is reacted with water to produce a dry white calcium hydroxide (Ca(OH) 2 ) pow- der. It is very alkaline and applications of hydrated lime is in water treatment and minerals processing such as copper, zinc, gold and uranium, which require lime to maintain pH levels. One of the main appli- cations in South Africa is in the steel and minerals processing industries, and that is where we can’t and don’t want to compete because of the distance from markets and scale of operation. “Therefore we are focusing on the white lime market which is in the calcium hypo- chlorite (Ca(CIO) 2 ) sector as well as applica- tions where low impurity levels in the lime is a necessity. Our focus is thus on the import replacement of lime,” Terblanche says, adding that the company is working on a new product line which still needs a few changes, but which he believes will be very successful. He is hopeful that these innova- tions will enable further expansion leading to the construction of a second kiln. On themining side the overburden strip- ping is outsourced and drilling and blasting is carried out by Afrimat Contract Drilling. Loading, hauling and crushing is done by Cape Lime as is all internal transport. The operation is utilising a fleet of Mercedes 14 m 3 twinsteers. Terblanche

The high grade limestone at Cape Lime is among the best of its kind in South Africa.

The Cape Lime operation in Vredendal.

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MODERN QUARRYING July - August 2017