Modern Quarrying

The acquisition of Cape Lime in April 2016 is one of the group’s larger to date. At the sum of R276-million, this acquisition is another extension of the group’s diversification strategy aimed at leveraging off its core business, not only in new markets but by also offering new products in existing markets. Dale Kelly met up with Cape Lime managing director Gerhard at the company’s Vredendal operation in the Western Cape.

The history of Cape Lime dates back to 1946 when the first vertical shaft kiln was commissioned by Cape Lime Company Ltd on the farm Langevallei near Robertson in the Western Cape. Today, Langvlei has three kilns in operation calcining dolomite, which is mined and crushed on site. It also boasts the only pressure hydrator in South Africa.

Cape Lime strategic allianceCape Lime’s Fluid Bed Calciner (FBC).

The Vredendal operation came into existence in 1981 when the dolomitic aggregate operation was expanded to include the mineral filter plant. Further expansion included the erection of the high-grade dolomite blending plant for the glass industry in 1983 and the processing of high-grade limestone in 1993. A fluid bed calciner was commissioned in 2004, producing quality white lime.
Cape Lime was purchased from private owners and the empowerment group Dormell. “We are pleased to retain the expertise within the business. The company is well run and efficient and this makes integration into the Afrimat group of companies that much easier,” said Afrimat CEO Andries van Heerden at the time of the acquisition.

Terblanche, who says he is part of the furniture, continues heading up the operation in his quiet and efficient way. He joined Cape Lime in 1997 when it was owned by Trans Hex and says he was there for the wrapping up the loss-making Trans Hex lime division. “We tried to salvage the shaft kiln that had been erected by Trans Hex and struggled for about 18 months to get it going but in hindsight it would never have worked, and the best decision was to shut down the division and cut back on our costs.

“I have taken some interesting risks in my career, coming from De Beers into the then Trans Hex-owned Cape Lime, and I remained on when a lot of people decided to abandon ship. It was a long and stressful period during which we carried out due diligence studies for several interested parties, but I am glad I stayed on.”

Cape Lime is known for exceptional quality mineral products supplied to various niche markets such as manufacturing industries producing chemicals, filler, glass, paint and food products. Its products are also used for water purification, soil treatment, effluent treatment, building and construction. The mineral deposit is among the best quality of its kind in South Africa.

“We are far from the market which is one of our biggest disadvantages, but it has also forced us to look at a different segment of the market. There is a huge market on the Reef for acid mine drainage and transportation is a major cost factor,” he says. “It is the same for fluid gas desulphurisation (FGD) on the new coal-fired power stations for which there is a market of hundreds of thousands of tons of limestone and lime. And again transport is a problem. So we have come to terms with the fact that we can’t compete in the general lime and limestone market. Luckily we have a quality orebody and we are focusing on the niche end of the market.”

The operation is a limestone and dolomite mine similar to any quarrying operation but the difference is at least 80% of the material that is quarried and crushed goes through secondary and tertiary beneficiation steps.

The raw materials are supplied mainly into the glass industry. “We supply the three big role players with their dolomite and limestone requirements. This is not exclusively; we do have competition in these markets. Our dolomite supplied to PFG is the only suitable source in South Africa with the alternative being in Namibia,” Terblance tells Modern Quarrying. “We also supply part of Consol and Nampak’s glass requirements on the limestone side.”

“The limestone and dolomite at Cape Lime is processed through the same primary crushing plant alternatively, depending on the requirements for the secondary steps. The three crushing stages consist of the primary crushing plant which is a Telsmith jaw crusher, the secondary is a Sandvik and the tertiary is an Osborn 38H,” he says. “The secondary and tertiary crushers have closed loop screening and the plant is set up in such a way that you can use a couple of diverters in the chute work to produce any of the G products in the same set up.

“The primary crushing plant hasn’t changed much over the last few years, but the ‘latest’ addition is the Sandvik crusher in the secondary application, which I must say, is a wonderful machine. It has been running trouble-free for 10 years,” he says.

The operation has its own workshop, but wear and tear is minimal because of the low silica content of the material. The plant is able to run for about six to seven years on a set of liners where some aggregate producers are fortunate 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 and the destination. Aggregate is sold from the primary stockpiles and we feed the secondary process 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 clients in the effluent treatment industry. The limestone is fed to the kiln and calcined at roughly 900o to convert the calcium carbonate to calcium oxide.

“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 powder. It is very alkaline and applications of hydrated lime in water treatment and minerals processing such as copper, zinc, gold and uranium, which require lime to maintain pH levels. One of the main applications 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 hypochlorite sector as well as applications 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 innovations will enable further expansion leading to the construction of a second kiln.

On the mining side the overburden stripping 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 m3 twinsteers. Terblanche says ADTs are not suitable because of the distance between the two quarries; the dolomite operation being about 1,5 km and the limestone another 6,0 km from the crushing plant. “We have found the Mercedes twinsteers also give us the best efficiency.

“There are Hitachi excavators in both quarries, with the limestone operation having the larger machine due to the fracturing and hauling distance. The fracturing of the dolomite and limestone is two worlds apart. We are using double the explosives charge on the limestone, but it still produces far larger fragments and this is a huge cost factor in the production cycle.”

Asked about the life of the mine, he says the life of the dolomite is in excess of 50 years, while the limestone at current production levels is over 30 years.

What is exciting is the proposed project for the establishment of mining limestone between Vanrhynsdorp and Klawer along the N7, for which Cape Lime acquired the mining rights in 2011. “It is a higher grade than we are currently mining with some 29-million proven tons, running at 98% calcium carbonate and low in iron,” he says.

“The hauling distance to our current crushing facility is currently just not feasible. However, establishing a crushing facility on the new mining site is a huge advantage in terms of the overburden stripping ratio, changes the economics.”

The Cape Lime operation has some exciting times ahead, and as Van Heerden said at the time of the acquisition: “We are confident that the quality of these assets, coupled with the marketing strength of Afrimat, will ensure that the investment is quickly recuperated.”

Growth through diversification is much more than the philosophy of the Afrimat group. It has clearly become one of the most respected construction materials and industrial minerals supply companies in Southern Africa.

Afrimat has, for the past few years, made strategic acquisitions in order to diversify the group away from the traditional aggregates business. The acquisitions have ensured that the group has a more evenly-distributed revenue stream and good margins across the business.

Another recent acquisition is the Diro iron-ore mine in the Northern Cape, which the company hopes will start production shortly. With the operation’s 1-million t/year capacity, Van Heerden says the mine has excellent potential for growth.

To date, its portfolio includes 25 commercial quarries, three dolomite mines, four clinker operations; two limestone mines and one iron ore mine. Added to this are five sand and gravel mines as well as mobile crushing and drilling and blasting. In the concrete-based products sector, it has nine concrete brick and block factories and 16 readymix batching sites.

www.afrimat.co.za

Contact Modern Quarrying

Title: Editor
Name: Dale Kelly
Email: dalek@crown.co.za
Phone: 083 419 9162


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Name: Bennie Venter
Email: benniev@crown.co.za
Phone: (011) 622-4770
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