Tag Archives: South Africa

Weir Minerals Africa putting newly designed vibrating screens to the test

Weir Minerals Africa, having over the last 40 years proven the credentials of its Enduron® range of vibrating screens, is now locally designing and manufacturing new-generation linear motion vibrating screens.

One of these new, modern screen designs is part of a recent Weir Minerals Africa complete comminution plant contract for a South Africa mining project. The scope included two crushing stations, a screening station and all the related feed chutes, bins and conveyors.

According to Christian Stehle, Head of Engineering at Weir Minerals Africa, the company’s design capability provides the flexibility to produce vibrating screens to suit each customer’s plant layout. At the same time, the designs will optimise cost, efficiency and performance. South Africa also hosts Weir Minerals’ global screening and separation technology group.

“This expertise ensures that our robust Enduron vibrating screens provide exceptional classification and dewatering screening performance,” Stehle said. The screens are deployed in a wide range of minerals processing applications.

He noted that vibrating equipment is generally more challenging to design than static equipment due to the high frequency cyclic loading to which the machines are subjected.

“The final design must address key criteria like screening efficiency, throughput and loading, while still operating within the acceptable fatigue life limits of the materials of construction,” he said.

Stehle highlighted that the use of finite element analysis (FEA) tools allow engineers to optimise screen life by obtaining the stress and deflection levels in the equipment and applying the appropriate structural design and utilisation of materials in the areas experiencing high stresses.

“Traditionally, screen designs used to be heavier in an effort to extend the life of the equipment,” he said. “Using FEA tools during the design stage allows us to retain structural integrity while actually reducing the overall weight of the machine.”

While there are areas of high stress on the equipment that need more strength, technology tools indicate where lower stresses occur. In these areas, less steel can be used to make the structure lighter, according to Weir Minerals Africa. Leveraging this technology, the weight of some new-generation screens has been cut by up to 15%, the company said.

Stehle noted that Weir’s Synertrex™ IoT platform can also be applied to monitor and improve the performance of the company’s vibrating screens. Synertrex technology is an industrial internet of things system that allows operators to monitor every aspect of their equipment’s operation, to prevent problems and increase throughput.

Austin Engineering expands into South Africa with ETT partnership

Australia-based Austin Engineering says it has signed a partnership agreement with South Africa’s ETT to market and support their combined mining-oriented product ranges throughout Africa.

The agreement, which follows around 12 months of talks, will bring together two of the southern hemisphere’s largest mining equipment design and manufacturing entities, Austin said.

Austin has more than 50 years of global experience in engineering and manufacturing equipment for the mining industry with operations in Australia, Asia, North and South America, and now South Africa. ETT, meanwhile, is a privately-owned South Africa-based company with products already distributed in more than 20 countries around the world.

Austin Engineering Managing Director, Peter Forsyth (pictured on the left), said: “We are looking forward to growing this partnership. It gives both companies a solid and reliable platform from which to offer customers throughout the continent proven world-class products backed up by world-class service.”

ETT Managing Director, Andre McDuling (pictured on the right), added: “ETT’s manufacturing and innovative record, as well as our strong presence and product supply into Africa, is one of the key reasons why this partnership was formed. We are confident that the industry is ready for a partnership like this that will provide the widest range of mining attachments and support products in the world.”

The combined product range of the new partnership will include customised dump truck bodies, water trucks, diesel lube trucks, gooseneck-equipped recovery vehicles, tyre handlers, low bed off-road trailers and excavator buckets.

Trafo powers through at Mpumalanga coal mine

Trafo Power Solutions says it has recently completed a dry-type transformer contract as part of a significant upgrade at a coal mine, in Mpumalanga, South Africa.

This involved the design, supply and installation of two 200 kVA – 22 kV-400 V – dry-type transformers, according to Trafo Power Solutions Managing Director, David Claassen. Housed in specialised IP42-rated ingress protected enclosures, the units were specified by a design house on behalf of the end-customer, the dry-type transformer leader said.

“The contract demonstrated our application engineering capability and our experience in co-ordinating our solution within a larger project,” Claassen said. “This included meeting detailed specifications, and ensuring that our design for the transformers and their enclosures matched the requirements and constraints of the site.”

Trafo Power Solutions also equipped the units with the necessary earth fault protection and surge protection, as well as vibration pads, it said.

“Dry-type transformers are well suited for the coal mining environment, with its hazardous areas and its regulations to mitigate fire risk,” Claassen says. “The dry-type technology uses air to cool the transformers, doing away with the need to use oil as a coolant.”

Claassen emphasised that the absence of oil has advantages for safety, as the oil ignition potential is removed. The units can also be protected against fine airborne coal dust. An added environmental advantage is the lack of oil leaks contaminating the ground or water, too.

Weir Minerals improves plant uptime at mineral sands, gold mines

Two African mines are achieving increased production time and plant availability after converting to Weir Minerals rubber lining solutions, the company says.

A mineral sands operation in Mozambique approached Weir Minerals just over two years ago, after experiencing high wear on its pipe and launders. This was leading to frequent maintenance, leaks and downtime. The Weir Minerals team observed that part of the challenge was worn out and corroded metal work on the mine’s wet concentrator plants due to the proximity to the coast.

Access to reline the existing launders was difficult and posed safety risks necessitating a more effective solution, the company said.

The solution was to replace the competitors’ products – chemically-cured rubber – with Linatex® rubber and Linard® 60 rubber. This was done during the mine’s monthly shutdowns.

Whereas the competitors’ rubber lasted only two to three months, the Linatex and Linard linings are still in operation after 25 months, according to the company.

The Linard 60 rubber lining solution was also applied at a gold mine in South Africa’s North West province. The mine’s maintenance team had been replacing the rubber lining on mill feed hoppers and spouts every 10 days, but the Mechanical Foreman was looking for a more resilient solution.

The Foreman was not familiar with Linatex rubber products, so a trial using Linard 60 rubber was arranged, with the entire feed hopper and spout lined with this silica-reinforced natural rubber.

The results saw wear life increase to 12 weeks. With only the partially worn areas requiring relining, there was a reduction in relining costs. This, in turn, increased plant availability, resulting in fewer stoppages and reduced operating costs.

Linatex premium rubber is a proprietary vulcanised natural rubber produced through a process that uses high quality natural latex, according to Weir. “It has outstanding strength, resilience and resistance to cutting and tearing – with high performance in wet, abrasive conditions,” the company said.

Linard 60 rubber, which is silica reinforced, retains the natural strength and nerve of latex, while combining with the toughness needed for handling coarse materials, according to the company.

Kwatani upskills Northern Cape contractor to carry out maintenance work

Specialist vibrating equipment manufacturer, Kwatani, says it leveraging a recent multi-year service contract with a large mining customer in the Northern Cape of South Africa to further boost the area’s local economy.

Kim Schoepflin, CEO of Kwatani, said: “Our branch near the customer’s mining operation has for many years employed and developed local expertise. Our latest initiative takes this further, by upskilling a local sub-contractor to conduct certain maintenance work on our behalf.”

A lengthy selection process was conducted by Kwatani to find a suitable sub-contractor, followed by ongoing training to empower artisans and other workers with specialised skills. Schoepflin says it was also important to involve the mine itself, so that it remained confident in the strength of its supply chain.

“Promoting local employment, skills and sustainability cannot be a tick-box exercise,” Schoepflin says. “It has to be based on proper engagement, hands-on training and the sub-contractor’s own commitment.”

Mining legislation and regulatory pressure can tempt stakeholders to rush such a process, she warned. “This would be a mistake; rather, it should be treated as an opportunity to strengthen the capability of all stakeholders.”

Kwatani’s 35 years of experience in heavy duty minerals applications means the OEM now has around 800 vibrating screens and feeders in the Northern Cape. The maintenance contract is an ideal opportunity to involve and foster the technical capability of local players, Schoepflin says.

It was vital that the chosen sub-contractor already had considerable experience and capacity, equipment and relevant expertise, according to the company.

“As a South Africa OEM with our own technologies and intellectual property, we are able to certify the sub-contractor and their quality of work,” Schoepflin says. “Phase 1 of our initiative will see them conducting basic service and maintenance functions.”

Kwatani retains responsibility for all work conducted, and continues with services such as detailed technical inspections, engineering support, on-site testing and diagnosis. It also supplies OEM spare parts, ensuring quality control, increased lifecycle time and reduced downtime, the company said.

Schoepflin noted that communities countrywide are eager to see more benefits from economic activity, and the country’s Mining Charter provides clear guidance on how mining companies can contribute to this process. “Kwatani’s mining customer is therefore also eager and incentivised to promote local businesses, both directly and through the supply chains of its main local contractors,” Kwatani said.

Schoepflin highlights the importance of supporting local firms to build sustainability in the local economy. This also strengthens the skills base for this economy to diversify, making it less dependent on mining and more resilient to commodity cycles and eventual mine closure.

“Our own business is local from the ground up, sourcing 99% of direct purchases from inside South Africa,” she says. “So, we understand the positive role that local procurement and skills development can play.”

It also makes financial sense to root the company’s cost base in the local currency, making it less vulnerable to foreign exchange fluctuations and allowing more affordable and consistent pricing.

“Working collaboratively with our mining customers and businesses close to their operations, we can help spread local economic benefits,” she says. “In turn, we can continue to develop our focus on leading-edge technology and quality manufacture.”

Weir’s Cavex hydrocyclones boost yields, production at Yoctolux Collieries operation

Yoctolux Collieries in Mpumalanga, South Africa, has achieved improved yields and production throughput with the installation of a Cavex® 500CVXT20 DM hydrocyclone from Weir Minerals Africa, the OEM says.

Part of the Tala Group, the open-pit coal mine was looking to improve the performance of its dense media separation (DMS) circuit in its Wash Plant 1. The existing 610 mm cyclone, installed during the mine’s initial design phase, had an operational life of only six months between refurbishments.

Members of the Weir Minerals Middelburg branch and hydrocyclone product team conducted a site audit, revealing the incumbent cyclone was operating inefficiently. A “wash-ability” analysis showed that an improved yield could be achieved using the Cavex hydrocyclone technology on the DMS circuit, Weir said, with the customer specifying that the product would have to offer improved separation efficiency, increase wear life and match the existing cyclone footprint.

Following a proposal that included dense media (DM) hydrocyclone simulations, a Cavex 500CVXT20 DM hydrocyclone was installed in August 2017. Manufactured from mild steel, it is lined with 25 mm slip-casted radius ceramic tiles manufactured with 92% alumina content.

To date, the hydrocyclone has achieved higher separation efficiency through an average 15% yield increase, according to Weir. It has achieved an overall average of 75% yield for both of the mine’s coal types – grains and peas. This compares favourably with the 65% achieved previously by the competitor’s cyclone, Weir said.

There has been a 49% throughput increase in production tonnage, from 78 t/h to 116 t/h as a result of the reduced turbulence in the hydrocyclone’s design. The mine has also seen significant wear life improvement, with the Cavex DM hydrocyclone requiring only a spigot replacement after nine months, according to the equipment manufacturer.

So satisfied was the management at Yoctolux Collieries that they placed an order for an additional Cavex 500CVXT20 DM hydrocyclone in May 2018. This replaced the competitor’s cyclone on Wash Plant 2, with the replacement based on the improved metallurgical and operational benefits obtained by the Cavex hydrocyclones.

Ivanhoe looks to align Platreef mine advance with palladium, rhodium price run

Ivanhoe Mines says it is fast-tracking a feasibility study on a smaller-scale, early-stage development plan at its Platreef palladium, platinum, nickel, copper, gold and rhodium project, in the Bushveld Complex of South Africa.

The move comes as spot prices of palladium and rhodium – two key metals contained in the Platreef ore – have soared in recent months. This has propelled Platreef’s ‘metals-price basket’ to a new, all-time high, Ivanhoe said.

Palladium prices surpassed a record $2,100/oz recently as stricter air-quality rules continue to boost demand for the metal used in vehicle pollution-control devices, while the price of rhodium has surged 32% already this month, attaining a price of more than $8,200/oz – the highest price since it hit more than $10,000/oz in 2008.

Ivanhoe’s plan would accelerate the mine’s first production by using Shaft 1 as the mine’s initial production shaft, followed by expansions to the production rate outlined in the project’s 2017 definitive feasibility study (DFS), it said. Ivanhoe’s smaller-scale mine design would also be optimised to target the highest-grade areas of the mineral resource in close vicinity to Shaft 1.

Platreef’s Shaft 1 currently is at a depth of 957 m below surface. It is scheduled to be completed to a final depth of around 1,000 m by the end of July. Work on Shaft 1’s 950-m-level station (pictured) – the shaft’s third and final station – is expected to be completed in March 2020.

Shaft 1 was previously expected to become the primary ventilation shaft during the project’s initial 4 Mt/y production case, with Shaft 2, around 100 m northeast of Shaft 1, providing primary access to the mining zones.

Platreef has an estimated 26.8 Moz of palladium in indicated resources, and an additional 43 Moz in inferred resources. This is in addition to an estimated 1.8 Moz of rhodium in indicated resources and an additional 3.1 Moz in inferred resources. Both of these are at a 2 g/t 3PE+gold cutoff.

In July 2017, Ivanhoe, which indirectly owns 64% of the Platreef project through its subsidiary, Ivanplats, issued an independent DFS for Platreef covering the first phase of production at an initial mining rate of 4 Mt/y. The DFS estimated Platreef’s initial average annual production rate would be 476,000 oz of platinum, palladium, rhodium and gold, plus 21 MIb (9,525 t) of nickel and 13 MIb (5,897 t) of copper.

Rio Tinto bringing Richards Bay Minerals back online

Close to four weeks after deciding to curtail operations at its Richards Bay Minerals (RBM) operations in KwaZulu-Natal, South Africa, Rio Tinto says it has started the process of resuming work at the zircon, rutile, iron and slag works.

The U-turn follows discussions led by the Premier of KwaZulu-Natal, Sihle Zikalala, involving all stakeholders focused on securing stability in order to address the issues in the community and provide the stable environment necessary for RBM to resume operations, Rio said.

Rio, which owns 74% of RBM, previously made the call to suspend work to ensure the safety and security of its employees due to an escalation in violence in the communities surrounding the operations.

In the December 4 announcement, it said: “There has been an escalation of criminal activity towards RBM employees and one was shot and seriously injured in the last few days. As a result, all mining operations at RBM have been halted and the smelters are operating at a reduced level, with a minimum number of employees now on site. Construction of the Zulti South project has also been temporarily paused.”

In its latest statement, the company said a phased restart is now in progress across the operation, with RBM expected to return to full operations in early January, leading to regular production in early 2020.

Having previously advised of a force majeure in supply following the suspension, Rio is now contacting customers to say this declaration has been lifted. The company said it would also review the restart of the Zulti South project after normalisation of operations at RBM.

The $463 million Zulti South project will sustain RBM’s current capacity and extend mine life. RBM currently operates four mines in the Zulti North lease area, a mineral separation plant and smelting complex. The Zulti South mine will underpin RBM’s supply of zircon and ilmenite over the life of mine, according to the company.

Bold Baatar, chief executive, Energy & Minerals, said: “The safety and security of our people is always our first priority and we are pleased that we will now be able to get back to work creating value for our people, our communities, South Africa and RBM’s shareholders.

“I would like to thank the Government of South Africa and the Premier of KwaZulu-Natal for their support and assistance in getting us to a position where we can restart operations at RBM. I would also acknowledge the work of community leaders and the police over the previous few weeks.”

Rio previously advised that titanium dioxide slag production for 2019 was expected to be at the bottom end of 2019 guidance of between 1.2-1.4 Mt.

Metso equipment to rough up diamonds at De Beers Venetia mine

Metso is to install high-performance crushing and material handling equipment underground at the De Beers Group’s Venetia diamond mine, in South Africa, as part of an order booked in the September quarter.

In the throes of a transition from open-pit mining to underground operations, Venetia is reported to produce around 4 Mct/y, making it one of South Africa’s biggest diamond mines.

In 2013, an underground extension project commenced with plans to start producing carats in 2022, climbing to full production in 2025 and extending the mine life to 2046.

Metso said Venetia approached Metso to deliver two primary jaw crushers and a number of feeders. All the equipment will be installed underground, which is a very challenging installation, especially given the shaft constraints (dimensions) and weight limitations for transportation underground, the company added.

Venetia decided on Metso’s Nordberg® C Series™ jaw crusher range as the pinned and bolted design of the crusher allowed for the extensive disassembly, Metso said. “This enhances ease of transportation and installation, especially where there are critical space constraints such as an underground installation – as is the case with this project.”

The Metso apron feeders, meanwhile, are used for extracting or feeding ores that are wet, sticky, dry or even frozen.

MechProTech collaborates with Vesconite Bearings on new mills, scrubbers

Mineral processing equipment manufacturer and designer, MechProTech, has introduced hydrodynamic composite bearings made from Vesconite Bearings’ vesconite thermopolymer plates for use on mills and scrubbers for the mining industry.

These plates, which are bent into a half moon or quarter moon shape, are used on the mineral processing equipment MechProTech designs and manufactures.

The bearings run on an oil film, so there is no surface contact between the bearing and the outside support for the mills and the scrubbers, and, as a result, there is no energy-consuming and grinding friction during operation, according to MechProTech Sales Manager, Wynand Boshoff.

“Vesconite is a sacrificial bearing that provides support. If the oil that the bearing runs on breaks down, there is no damage to our equipment,” he says.

The advantages of using vesconite also extend to cost, operations and logistics.

MechProTech noted that the hydrodynamic bearings are less expensive in this application than white metal bearings, which can be six times more expensive than the thermopolymer bearings, and are also hard wearing and grease free, requiring little maintenance in an industry in which machinery downtime can be costly.