Tag Archives: Kwatani

Kwatani breathes new life into scalping screens with rubber, polyurethane wear panels

As mines move towards using one large scalping screen between primary and secondary crushers – rather than a modular approach using multiple smaller screens – Kwatani says it has found ways to triple the panel life in these single mission-critical units.

According to Kenny Mayhew-Ridgers, Chief Operating Officer of Kwatani, any downtime in this single-line stream would require the mine to store several hours of production. While some mines schedule regular weekly production halts during which an exciter or worn screen panels can be replaced, many operations are not so lenient, he said.

“The message from these mines is clear: the longer the scalper can run between maintenance interventions, the better,” Mayhew-Ridgers said. “Our research and development efforts, together with extensive testing in the field, have allowed us to extend the life of screen panels from eight weeks to over six months.”

While smaller screens use wire mesh screening media, Kwatani has evolved larger screens that use rubber or polyurethane screen panels. Although these panels present less open area, they deliver important advantages.

“Key to the success of our design is our integrated approach – which matches the panel design with that of the scalping screen itself,” Mayhew-Ridgers said. “This allows us to achieve a balance between screening area, aperture layout and screen panel life – a result based on a sound understanding of screen dynamics.”

Whereas wire mesh undergoes rapid wear from abrasive materials, the rubber or polyurethane panels are more wear resistant and deliver longer life, according to the company. The latter require gentler declines for effective stratification, but a key factor is the stiffness of the screen bed.

“The stiffness of the supporting structure must go hand-in-hand with the screen panel design to achieve our required results,” Mayhew-Ridgers said.

Polyurethane panels, while strong and lightweight, have screening apertures that tend to be too stiff for heavy-duty scalping applications. This leads to blinding. Rubber overcomes this problem, however, and also delivers improved wear life.

Kwatani has also developed a panel replacement system – with a fastening mechanism on the underframe – that improves safety and saves time, it says.

Kwatani branching out from South Africa roots

Vibrating screen and feeder specialist Kwatani says it is transitioning from equipment supplier to solutions provider, as it attracts customers from well beyond its South Africa headquarters.

According to Kwatani General Manager Sales and Service, Jan Schoepflin, the company’s strong in-house expertise and design capability – combined with the manufacturing quality it consistently achieves – ensures its customised solutions deliver optimal performance at the lowest possible lifecycle costs.

“Our recent orders show that our customer base in Southern Africa remains strong, while there is growing recognition of our cost-effective offerings in West Africa, East Africa and North Africa,” says Schoepflin. “At the same time, orders from countries like Canada and Russia indicate that our markets abroad continue to grow.”

Kwatani says it remains the market leader in the supply and servicing of vibrating screens and feeders on iron ore and manganese mines in South Africa’s Northern Cape province. It also counts platinum, coal, diamond and gold mines in its customer base. Its West Africa orders have been mainly to gold mines, and there is growing potential for gold mining in East Africa, Schoepflin says.

Over its four decades of operation, Kwatani has produced about 16,000 custom-designed screens, and is building, on average, 30 to 40 units a month in its ISO 9001:2015 certified facility close to OR Tambo International Airport in Johannesburg.

“Our reputation has been built on prioritising what our customers need, and doing business with integrity and trust,” Schoepflin says. “This means delivering on what we promise and making sure that customers achieve the expected value from our products.”

The company’s solution focus is underpinned by its significant and ongoing investment in local skills, ensuring that its designs leverage strong mechanical and metallurgical engineering expertise, according to Schoepflin.

“This confidence in our products allows us to offer a process guarantee to customers, to deliver the tonnage, throughput and fractions that they expect,” he says. “Depending on which country our customers operate in, they may also have different industry and quality standards/certification expectations and we work closely with them to understand these clearly and meet their requirements.”

Schoepflin also emphasises the company’s service capabilities, which include its local service centres closer to customers, and its support partners in other countries.

“The careful selection of these partners is vital to meet customers’ stringent technical expectations,” Schoepflin says. “In some countries, our partners can also manufacture components according to our drawings and specifications, should there be an urgent requirement from a customer.”

Kwatani collaborating with EPCMs, miners on bespoke screening options

Mineral process plant designs are favouring higher-capacity vibrating screens and a more holistic approach to plant optimisation, according to screen specialist Kwatani.

“These trends hold great potential for the mining sector, and Kwatani has been at the forefront of technologies driving this direction,” Annelize van der Walt, Kwatani’s Business Development Manager for Mining and Minerals, says.

Vibrating screens are essentially the “glue” that integrates various unit processes, from bulk materials handling to optimally liberated comminution and pre-concentration, according to the company.

“Larger, engineered-for-tonnage screens are growing in popularity, as they reduce the number of processing modules and hence the level of infrastructure required, especially on mega-projects,” van der Walt says. “Higher capacity is becoming the new design standard for greenfields projects.”

There is also an ever-greater demand for reliability and uptime in these mission-critical machines, as well as an expectation of longer lifespans. All this requires bespoke solutions that address site-specific conditions, van der Walt says, while leveraging digital technology for real-time monitoring and control.

“Kwatani’s metallurgists and engineers use their extensive on-site experience and in-house laboratory facilities to innovate from our proven technologies,” she says. “A cornerstone of our philosophy is close collaboration with engineering, procurement and construction management contractors and end-customers to customise solutions, from concept to construction, commissioning and operation.”

Annelize van der Walt, Kwatani’s Business Development Manager for Mining and Minerals

Specific conditions include waterless beneficiation in arid Mauritania, where Kwatani’s screens operate completely dry in an iron ore plant. In South Africa and Botswana, meanwhile, the company has retrofitted dewatering screens to reduce water consumption, while increasing output by 40% with the same footprint.

“We also recently designed screens for exceptional ore characteristics in a precious metal beneficiation facility in Canada,” she said. “This required a high level of customisation, not only in the screening media but in the mechanical design.”

Remote mine locations – which are difficult to access for maintenance and replacement purposes – also guide the design parameters. In a recent project, Kwatani innovated by selecting special hard-wearing materials for the construction of the screening equipment. The design included components that would provide early warning of wear.

Embracing a more holistic plant design approach, customers often invite Kwatani to participate in optimising the screening side of their chosen beneficiation technology, van der Walt says. A different screening approach would be taken, for instance, in a dry pre-concentration application than in wet dense medium separation.

“This holistic approach is also facilitating greater synergy between original equipment manufacturers,” she says. “This is a very positive trend, allowing us to consider the impact of different equipment on the performance of each – from mineral processing apparatus to transfer chutes.”

Underpinning Kwatani’s responsiveness to customer’s specific needs is its ongoing research and development.

“Our R&D unit is currently working on projects to suit our designs to novel crushing and grinding technologies, which are changing the whole approach to the process flow of future plants,” van der Walt says. “These are significant innovations for the mining sector, and we are excited to be at the forefront with our evolving screen designs.”

Kwatani is incorporating digital technologies to facilitate remote monitoring and control of its vibrating screens. It is also piloting a service app for mobile phones, which helps operations predict their maintenance needs more accurately. The app also helps to drive down the total cost of ownership by gathering data that can be used in future design improvements.

Kwatani problem solving doubles diamond mine’s screening feed rate

Kwatani says it has helped a South Africa diamond operation double the feed rate of its degrit screen through the use of one of its customised solutions.

The customer was operating several multi-slope screens to dewater product between 0.8 mm and 5 mm in size, before it was treated by dense medium separation (DMS). However, the screens were causing a severe carry-over of water onto the conveyor belt to the DMS, according to the South Africa-based OEM.

“The feed rate on each screen was being limited to about 250 t/h,” Kwatani CEO, Kim Schoepflin, said. “We tackled this by designing and manufacturing a customised multi-slope screening machine to fit the customer’s existing footprint.”

Schoepflin said Kwatani’s replacement was able to double the feed rate to about 500 t/h, with minimal water carry-over.

As a result of the success of this unit, the customer requested Kwatani to replace the whole bank of screens, it said.

In another contract, a customer asked for assistance with underperforming screens that could not deliver the original design parameters. They also wanted to increase the tonnage throughput by 17%, according to the company.

“We conducted a careful evaluation in collaboration with the customer, and came up with an innovative and economical solution,” Schoepflin said. “Simply replacing the existing screens with Kwatani’s new larger screens would have been costly and time consuming, so we decided instead to replace the screen’s existing gearboxes.”

The replacement gearboxes delivered greater vibration, but without exceeding the output torque the existing motors driving the gearboxes could provide.

“Drawing from our portfolio of locally designed and manufactured exciter gearboxes, we were able to implement this solution very quickly,” she said. “The two new exciter gearboxes were delivered to site and were in operation within two weeks – successfully and immediately increasing the screen’s throughput.”

The benefits to the customer did not stop there, according to Schoepflin. The newly optimised operating parameters meant the material bed depth was lower, so the drive motors drew a lower amperage and reduced the cost of power consumed.

“Our customised screening and feeding solutions – developed by our in-house team of experienced mechanical engineers and metallurgists – are based on consultation with each customer,” she explained. “The result is a design that delivers the optimal processing performance and tonnage at the lowest cost of ownership.”

Kwatani solves the screening equation at South Africa coal processing plant

Kwatani has once again shown its mineral processing expertise in a retrofit project that saw one of the largest coal processing plants in South Africa boost screening throughput.

The South Africa-based company was brought in to consult on possible solutions to assist the plant in not only returning its screening throughput performance to the original design parameters but increasing it further.

Kwatani Chief Operating Officer, Kenny Mayhew-Ridgers, said: “Having evaluated the challenges on site and consulted extensively with the plant personnel, we determined that the suggestion to incorporate a bigger gearbox onto the screen would fail.”

The screen lifespan was in excess of six years and Kwatani determined it would not be able to accommodate substantially larger gearboxes offering 50% more output than the currently installed exciter gearboxes. “This would have resulted in irreplaceable damage to the screens,” Mayhew-Ridgers stated.

Because the customer was also looking for a quick and cost-effective solution, purchasing new screens with larger vibration capabilities was not an option, according to the company.

Kwatani came up with a simple solution, according to Mayhew-Ridgers.

“The plant was achieving 450 t/h on 480 t/h screens and was looking to increase this to about 525 t/h. This equated to roughly a 17% increase in performance. Replacing the screen’s existing gearboxes with those that could deliver greater vibration but would not exceed the output torque that the 37 kW drive motor could provide was the answer,” he said.

With a range of locally designed and manufactured exciters gearboxes in its portfolio, Kwatani was quickly able to provide the customer with two new exciter gearboxes delivered to site, installed and operational in the two-week timeframe the customer was looking for. “The increase in screen throughput was immediate,” Mayhew-Ridgers said.

The success of the retrofit saw Kwatani secure the order to replace three additional screens for the customer with new exciter gearboxes now currently operating at 550 t/h – 22% more than the original requirement. “Our success has proven our capabilities and screening knowledge and we have further secured all the screen repair work as well,” Mayhew-Ridgers added.

“We have positioned this business to offer expertise that extends beyond the supply of screening equipment. Our product knowledge enables us to correctly specify the right equipment and components for the application – in a case-by-case scenario,” he concluded.

Kwatani screens and feeders tackle manganese ore in South Africa

As a vital aspect of a plant expansion at a manganese mine in the Northern Cape of South Africa, Kwatani says it is supplying four heavy duty vibrating screens and 10 feeders to help boost throughput.

According to Kwatani CEO, Kim Schoepflin, this large-scale equipment is custom-designed and engineered for tonnage to meet the mine’s challenging operational requirements.

“Manganese ore is very demanding on vibrating screens as it has a high specific gravity and is also very abrasive,” Schoepflin says. “Our machines are engineered to perform the application’s duty requirement while being robust enough to deliver maximum uptime.”

The units being supplied include a 3.6 m double-deck scalping screen, a 3 m double-deck screen, a 2.4 m screen and a 1.8 m dewatering screen. A local OEM that has designed and engineered vibrating screens for over four decades, Kwatani has built a reputation for world-class expertise and capability, it says.

“Customers choose us for our engineering track record – developing technology that can manage the tonnages they require,” Schoepflin says. “This means understanding each mine’s specific conditions, and then building a design to meet a range of complex mechanical and metallurgical factors.”

The order to the mine is being rolled out on time and on specification to the customer’s satisfaction, according to Kwatani COO, Kenny Mayhew-Ridgers.

“The efficiency and quality of our work process allows us to design, manufacture and deliver custom-designed screens in the same timeframes that other OEMs deliver standard models,” Mayhew-Ridgers said.

This is particularly demanding as custom-designed equipment undergo an intensive design process after being verified by rigorous finite element analysis in-house, Kwatani says. Prior to dispatch, all units endure intensive testing before being commissioned on a customer’s site. For this reason, Kwatani boasts its own in-house advanced testing facilities at its Kempton Park facility, in South Africa. Aligned to ISO 9001 standards, the testing protocols have been developed in-house with decades of experience. This allows full testing similar to cold commissioning, even before delivery to site.

Kwatani stresses importance of screen servicing

To ensure uptime on critical equipment, maintenance contracts are becoming an ever-more popular choice, according to vibrating equipment OEM, Kwatani.

The South Africa-based company should know, as it has customised contracts in place to service over 500 of its machines in the Northern Cape alone.

“Vibrating screens are critical to a mine’s material flow, which is its lifeblood,” Kwatani CEO Kim Schoepflin, says. “This requires OEMs to be experts, not just in design and manufacture, but in service support and maintenance.”

As a leading local OEM, Kwatani has seen mines gradually embrace the value of maintenance contracts to avoid costly downtime. One of its contracts covers about 400 screens on a single mining operation.

The range of its contracts extends to various commodities, from hard materials like iron ore and manganese to soft material such as coal. In one coal operation in Limpopo, Kwatani has contracted to service 160 of its machines.

Schoepflin highlights how regular, expert maintenance is vital for mines to achieve the lowest cost per tonne in their production process. However, she warns these contracts can only be conducted responsibly and effectively with the right level of knowledge and experience.

“With our depth of know-how gathered over more than 40 years, we understand exactly what inspections and critical replacement need to be done and when,” she says. “As importantly, we know how to conduct this work cost effectively.”

Accurate costing of maintenance contracts can only be based on a firm foundation of expertise, especially when contracts invoke penalties due to breakdowns. Kwatani’s experience in the field ensures the requirements of its maintenance contracts are met. This allows the company to offer a range of financial models to customers when they consider such contracts.

“We are so confident of the quality and reliability of our vibrating screens and feeders that some customers pay us a cost-per-tonne rate to maintain them,” she says. “We design, manufacture, install and commission according to their requirements, and then we take financial responsibility for keeping them fully operational.”

Long-term contracts often also include a commitment to improve and enhance the performance of the screens over time. To do this work professionally requires qualified service teams who are supported by solid engineering teams. Kwatani has developed these resources locally over more than four decades, and continuously develops skills in-house, alongside the various management systems to ensure such skills are available timeously to the customer.

“In addition to training and employing local people for a service role at our branches, we also collaborate with mining customers to empower their locally-based suppliers where this is feasible,” Schoepflin says.

She highlights Kwatani’s solution-orientated approach, combining the company’s expertise in its screening technology with the customer’s specific needs and resources.

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.”

Weba Chute Systems and Kwatani save the day at South Africa gold mine

Weba Chute Systems and Kwatani have come together to design and install ore silo chutes at a South Africa gold mine to reduce mill wear and other processing challenges caused by the uncontrolled flow of mined material into the mills.

The solution from Weba and Kwatani, a leading local manufacture of vibrating screens and feeders, must also deal with frequent large-size material as the mine has no crushing stage before the milling circuit, Weba said.

According to Weba Chute Systems Technical Advisor, Alec Bond, the over-feeding of material through the existing manually operated chutes is causing regular “mill vomit” in the mine’s four mills. The inconsistent feed exacerbates wear on mill bearings as the material’s weight shifts forwards and backwards inside the mill.

The waves of material causing the “vomit” carry insufficiently milled material out of the mill, including large chunks of rock. This leads to problems for the downstream mineral processing facilities, including inefficient recovery in flotation cells and even blockages in pumps, according to Bond.

“The challenge starts with the existing chutes needing constant supervision and control by operators, being opened and closed with a chain block device,” he says. “Our solution was to design a robust, self-controlling chute and feeder system that would ensure an even flow of material into the mills.”

He explained that the mine’s existing system has no means of closing the silo outlet; any maintenance at the chute area requires the emptying of the silo and the stoppage of the mill. Each of the four silos has three outlet chutes.

Weba Chute Systems Designer, Wesley Hunkin, says: “We therefore added a spile bar arrangement which seals off the silo. The Weba chute, which is choke fed, is placed under this installation. This allows the feed rate to be controlled by the Kwatani feeder, which has been integrated into the chute design.”

The vibrating action of the feeder controls the tonnage and feed rate to the mill, keeping the flow constant. New mounting structures have been designed to accommodate each chute and feeder. There will also be civils works below the silo to provide a solid foundation that absorbs vibrations from the feeder, according to the companies.

A serious challenge is over-sized rocks in the ore feed, which can be up to 800 mm in size. This makes it important for chute designs to accommodate the worst-case scenario of chutes choking, says Hunkin.

He highlighted that the flow of material is also controlled to prevent direct impact onto the conveyor belt feeding the mills, and to ensure central loading onto the centre of the belt.

“If the material from the feeder is biased to the one side, our chute brings everything to the centre of the conveyor,” he says. “This enhances the consistency of material flow into the mill.”

Bond emphasised that the customer motivated for a concept change to address the challenges being experienced with the silo feed.

“Given our materials handling experience, design expertise and high-quality local manufacturing facility, we were able to work closely with the customer and with Kwatani to turn this new concept into reality,” he said.

“Our solution promises direct savings in terms of mill bearings, as well as less mill downtime. There will also be significant gains in terms of recovery rates in the plant if the flow and size of milled material can be improved.”

Kwatani makes manufacturing commitment on comminution equipment

Vibrating screen and feeder original equipment manufacturer (OEM), Kwatani, is promoting the need for high-quality engineering and the strictest tolerances for unbalanced motors and gearboxes to ensure components can run over the long term.

The harsh operating conditions that screens face in mining operations makes having these safeguards in place all the more important, it says.

According to Kenny Mayhew-Ridgers, Chief Operating Officer at Kwatani, local design and manufacture to the highest standard is a “non-negotiable”, with the OEM designing its own range of motors, as well as locally manufacturing the gearboxes for its vibrating screens.

“We design our own motors with local conditions in mind, giving the customer a high performance and long lasting product,” Mayhew-Ridgers says.

This includes optimal sealing arrangements for keeping electrical components dry and clean, Kwatani says. Power cables, for instance, must always enter from the underside to prevent water ingress, while the design must consider various orientations of the motor, depending on the angle of installation. Dusty conditions on mines also present a challenge that need to be addressed.

“Dust ingress can compromise the sealing configuration of the lid,” he says. “Our design is therefore like a top-hat, so the O-ring is not on a flat surface but rather on a cylindrical, vertical surface. There is even a double-sealing arrangement for the lid, which includes a gasket.”

Kwatani’s gearboxes are locally manufactured, with only the high quality bearings imported direct from leading global producers, it says. Gearboxes comprise two shafts, each with its own set of unbalanced weights linked to each other by a gear to achieve synchronised motion. Gears and shafts, meanwhile, are locally fabricated by selected suppliers, while the housing is cast by a local foundry and machined to exacting specifications.

“We have spent a great deal of effort on the sealing configuration, to ensure no oil leaks,” he says.

Mayhew-Ridgers says Kwatani is probably the only OEM that services its own gearboxes. This, he says, ensures adherence to strict tolerances, so that units have sustained performance and longevity.

He also highlights the massive centripetal forces exerted on the screening machine by the unbalanced motor and gearbox, which makes it vital to secure them well to the screen.

“To achieve this, we specify our own fabricated bolts, nuts and washers,” he says. “If sub-standard fasteners are used, components can come loose and cause extensive damage.”

Unbalanced motors usually have to be installed at an angle. Taking account of the weight of these components, there are rigging points all around the housing to manipulate the angle of installation. The feet of are normally larger in Kwatani installations than those of competitors, for a better contact surface, the company says.

“If there is the slightest imperfection in the flat surface of the join, this can cause costly damage to the drive and the screen,” Mayhew-Ridgers says. “This is why OEMs like Kwatani have such detailed installation procedures on issues like torqueing of bolts. Installers and maintenance teams need to stick closely to these specifications.”