Tag Archives: Kwatani

RESEARCH STUDY LEADS KWATANI TO BETTER BANANA SCREEN DESIGN

Numerical simulation research that modelled the behaviour of particles on a conventional banana screen has been leveraged by local vibration screen specialist Kwatani to make fundamental improvements in the design.

So important were Kwatani’s adaptations that they were able to double the throughput of a competitor’s problematic dewatering screen on a customer’s mine, where excessive water carry-over was limiting production potential. 

According to Kwatani chief operating officer Kenny Mayhew-Ridgers, the company’s depth of mechanical and metallurgical expertise underpins its ability to apply what it learns from research and field testing. 

“This specific research, which was done by Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the University of Queensland, highlighted that the traditional feed-end slopes of banana screens were generally too steep,” says Mayhew-Ridgers. “At around 34°, these slopes create material velocity in excess of 3 m/s – too high for efficient screening.” 

He considers that a more suitable slope at the feed end is 25°, leading into five or six deck slopes in the screen and ending with a discharge slope of just 5° or even 0°. This would ensure that the material velocity was less than 0,5 m/s at the discharge end. The drive angle, operating speed and stroke are also significant factors, he says.

“Our analysis allowed us to address a challenge that a customer was experiencing with their degrit screens,” he says. “Water carry-over from the screen to the conveyor belt was limiting throughput to only 250 t/h, and the mine needed more than that.”

Kwatani’s changed the screen feed-end slopes and incorporated a long discharge-end decline slope of 3°. The drive angle was also increased to 50° to improve the dewatering performance of the screen. These adaptations were possible within the constraints of existing chute work, motor base position and support structure. The size of the screen – measuring 3,66 m wide – meant that a considerable load needed to be supported on the screen deck, so circular hollow sections provided improved strength in place of the H-profile deck beams usually employed.

“The modifications were successful,” he says. “The mine’s plant manager was able to confirm that  the feed rate had been increased to 500 t/h with very little water carry-over, and this performance was consistently maintained.”

The application of the new design was outlined in a peer-reviewed paper by Mayhew-Ridgers and Kwatani director Derrick Alston, which was presented at an international mineral processing conference. 

SANDVIK AND KWATANI ANNOUNCE GAME-CHANGER FOR VIBRATING EQUIPMENT INDUSTRY

In an exciting joint announcement, Sandvik Rock Processing Solutions and Kwatani have confirmed that an agreement has been signed for the multi-national Sandvik Group to acquire the shares of this leading African OEM of custom-engineered vibrating equipment. The transaction is expected to be finalised around the fourth quarter of 2021, subject to regulatory approvals and other customary conditions. 

Kim Schoepflin, CEO of Kwatani, says not only is this a complete game-changer for the vibrating equipment industry, but customers will benefit enormously from the combined resources of Sandvik and Kwatani. Both companies are technology leaders in their own rights with Kwatani having operated its world class production facility in Johannesburg, South Africa, for more than 45 years. 

“What is most significant and exciting for the South African economy is that our facility is set to become the global engineering and manufacturing base for vibrating screens and feeders for both local and international customers,” Schoepflin says. 

This collaboration is not only a major milestone for the South African engineering industry; it is also in line with the South African government’s industrialization strategy. Schoepflin is also quick to point out that Kwatani will continue with its commitment to transformation and compliance with the South African Mining Charter. 

Commenting further, Schoepflin says that the internationally recognised Kwatani brand will remain unchanged. “Known for our brand promise of being engineered for tonnage, we will continue to use the Kwatani brand across Africa and products sold internationally will be sold through the Sandvik sales channels under the Kwatani product name.”

Sandvik will further develop the Kwatani vibrating equipment brand globally with increased access to the product through its global distribution network. Schoepflin explains that customers will benefit further by having access to a vastly increased customer service network. 

Speaking about future developments, Schoepflin says that Sandvik, through its global technology resources, will provide access to monitoring and automation processes as well as access to its extensive R&D facilities which include simulators. 

“This will provide opportunities for driving efficiency arising from the advance of artificial intelligence in the Fourth Industrial Revolution and will significantly empower the process of cost effective customisation,” she says. 

KWATANI SCALPERS TREBLE PANEL WEAR LIFE

As mines move towards using one large scalping screen between primary and secondary crushers – rather than a modular approach using multiple smaller screens – Kwatani 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 could be replaced, many operations are not so lenient, says Mayhew-Ridgers.

“The message from these mines is clear: the longer the scalper can run between maintenance interventions, the better,” he says. “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,” he says. “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. 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,” he says. 

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. 

KWATANI GROWS ITS BASE OF CUSTOMISED SCREENING SOLUTIONS

As leading vibrating screens and feeders specialist Kwatani has transitioned from equipment supplier to solutions provider, it has attracted customers from well beyond South Africa and even outside Africa.

According to Kwatani general manager sales and service Jan Schoepflin, the company’s strong in-house expertise and design capability – combined with the world-class manufacturing quality it consistently achieves – ensures that 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 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 African orders have been mainly to gold mines, and there is growing potential for gold mining in East Africa, he 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.”

He highlights that 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. 

“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 to be 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.”

COAL MINES NEED LOWER COSTS, RAISED PRODUCTIVITY

Despite South Africa’s energy supply being heavily reliant on coal, weak prices and more demanding mining conditions are putting pressure on coal mines and their suppliers to do more with less.

“Coal prices are low and any recovery in the short term is very unlikely,” says Frengelina Mabotja, senior metallurgist and capital sales engineer at vibrating screen specialist Kwatani. “Going forward, as coal seams with more overburden have to be mined, surface mining will potentially become much more expensive.”

Adding to the coal industry’s challenges is the unwillingness of many lenders to fund new coal plants and expansions, leading to great uncertainty. The result is a strong drive for ongoing cost reduction and increased productivity across both majors and juniors in the sector, says Mabotja.

“While most of SA’s coal supply is produced by a handful of major mining houses, Eskom has in recent years sought to develop the junior market with black ownership,” she says. “Kwatani partners with majors and junior miners alike, offering two distinct equipment ranges tailored to each segment’s specific requirements and capital budget.”

With its 44 years of local and global experience, Kwatani provides customised, cost effective processing solutions for mines’ specific needs. She notes that vibrating equipment requirements can vary significantly between a smaller-scale junior miner and a long-life major. This is in terms of the equipment’s size, operating lifespan, tonnage throughput, efficiency and yield requirements.

“Apart from the initial capital expenditure, mines’ process equipment has an enormous influence on their production efficiency, tonnage and operating cost,” she says. “Our long-lasting, robust vibrating screen and feeders are designed for continuous tonnage throughput and high efficiency. This reduces the processing cost per ton and the overall cost of the machine over its lifetime.”

For the large mine segment, Kwatani’s designs have included high capacity and performance screens such as its 4,3 m wide banana screen. Its brute force grizzly feeders for run-of-mine (ROM) operations are capable of sizing and feeding material at up to 2 000 tph, even from high drop-heights.

“Our engineering team has optimised the structural integrity, weight distribution and lifespan of this equipment,” says Mabotja. “We have many of our 4.3m wide banana screens operating at the largest opencast coal complex in the world.”

At the same time, Kwatani supplies screening equipment below 2,4 m wide for smaller-scale, modular plants processing up to 250 tph. These units are tailored to budget and provided within short delivery times.

LOCAL QUALITY DRIVES KWATANI’S EXPORT SUCCESS

Quality local design and manufacture have catapulted Gauteng-based Kwatani into the global marketplace with its world class vibrating screens.

With an established footprint around Africa, Kwatani’s exports have grown to include 40 countries worldwide in the eight years since it began supplying abroad.

“Our success is based on years of local investment – in skills, technology and infrastructure,” says Kim Schoepflin, CEO of Kwatani. “This has given us a very high level of local content, which supports a local supply chain while advancing the expertise on which our economy can grow.”

The technical capability that has been developed underpins the performance and reliability of the company’s custom-engineered screens. Its ‘engineered for tonnage’ motto has rung true for the growing base of customers abroad.

“As with our local market, we prioritise the support services available where export customers operate,” says Schoepflin. “In fact, we prefer not to supply machines into areas where we have not yet established a support partnership with suitable experts.”

In Canada, for instance, Kwatani now has representation in both the eastern and western regions, and its first machine was recently shipped into the Canadian market. The bespoke nature of the company’s screens means that service partners need an appropriate level of technical expertise – and even considerable refurbishment facilities.

Kwatani is no stranger to working remotely from customers, Schoepflin notes, serving mines and project houses which are often based in other countries, and even in a different country to the project’s actual location.

“Our technology base and use of online communication platforms means that our work frequently transcends borders,” she says. “This also ensures that the Covid-19 pandemic will not put a dampener on our globalisation drive.”

Schoepflin highlights the company’s strict adherence to ISO quality systems and procedures, which are a vital component of the technical excellence required when playing on the global stage.

DESIGN, REAL-TIME MONITORING KEY TO PROCESS EFFICIENCY

While the ramping up of production since South Africa’s Level 5 lockdown has brought some relief to mining companies, the pressure on efficiencies is unrelenting.

Highlighting the virus-related cost burden on mines – from Covid-19 protocols to temporary shutdowns – Kwatani CEO Kim Schoepflin says raising process efficiency is non-negotiable.

“Increasingly scarce resources and cost pressures are challenging the mineral processing industry,” says Schoepflin. “More than ever, each piece of equipment in the process must deliver efficient output to the exact specification at the lowest cost.”

She emphasises design and monitoring as key factors in continuously improving efficiency levels. As a local manufacturer of custom-designed vibrating screens and feeders, Kwatani leverages cutting edge technology with decades of field experience.

“Using our virtual design software tools – and digitally prototyping customers’ ore and processing flows – we generate bespoke solutions for each application,” she says. “We work as a team in an ecosystem that includes metallurgists, engineers and end-customers – collaborating right through from concept to production.”

Kwatani’s designs benefit from the latest 3D modelling and design techniques, and are subjected to finite element analysis (FEA) to verify engineering integrity. All Kwatani’s vibrating equipment is assessed with in-house test facilities for conformance to the design specification under ideal operating conditions.

“Ongoing monitoring is also vital to ensure that planned efficiencies are being met, and the lowest cost of ownership is being achieved,” she says. “This is supported by our real-time condition monitoring service offering.”

Schoepflin sees even greater opportunities for driving efficiency arising from the advance of artificial intelligence in the Fourth Industrial Revolution. With the advantage of the internet-of-things (IOT), mobile networks and other digital technologies, the process of cost effective customisation has been significantly empowered.

“This evolution is taking the customisation of our equipment into the future, including real-time customisation,” she says. “It promises to allow for multiple activities to be simultaneously tackled in real-time and in a customised manner.”

Such progress in increasingly demanded by the mining sector, as cost and performance drive the need for technology-driven efficiencies.

KWATANI GEARBOX DELIVERS EXCELLENT SCREENING PERFORMANCE IN COAL APPLICATION

Kwatani’s objective to position itself as an expert and advisor for screening applications has seen it execute a project that successfully delivered optimised throughput performance for one of the largest coal mining companies in South Africa.

Kwatani was brought in to consult on possible solutions to assist one of the largest coal processing plants in the country, not only return its screening throughput performance to its original design parameters but to increase it further as well.

“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,” says Kwatani chief operating officer Kenny Mayhew-Ridgers.

The screen lifespan was in excess of six years and Kwatani determined that 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 states.

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

Having evaluated the challenge, Kwatani realised the simplicity of the solution. “The plant was achieving 450 tph on 480 tph screens and was looking to increase this to about 525 tph. 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,” Mayhew-Ridgers outlines.

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 which were delivered to site, installed and operational in the two week time frame the customer was looking for. “The increase in screen throughput was immediate.”

The success of the retrofit saw Kwatani secure the order to replace the customer’s three additional screens with new exciter gearboxes which are now currently operating at 550 tph – 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 adds.

“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 concludes.

KWATANI’S SCREEN SOLUTIONS CUSTOM-BUILT FOR TONNAGE AND LOWEST TCO

When a South African diamond operation needed to improve the performance of its degrit screens, Kwatani customised a bespoke solution that doubled the feed-rate.

The customer was operating a number of 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.

“The feed-rate on each screen was being limited to about 250 tonnes per hour,” says Kwatani CEO Kim Schoepflin. “We tackled this by designing and manufacturing a customised multi-slope screening machine to fit the customer’s existing footprint.”

Schoepflin says Kwatani’s replacement was able to double the feed-rate to about 500 tonnes per hour, and 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.

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

“We conducted a careful evaluation in collaboration with the customer, and came up with an innovative and economical solution,” Schoepflin says. “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 that 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 says. “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, says Schoepflin. The newly optimised operating parameters meant that 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 says. “The result is a design that delivers the optimal processing performance and tonnage at the lowest cost of ownership.”

MANGANESE MINE UPS TONNAGE WITH KWATANI SCREENS

As a vital aspect of a plant expansion at a Northern Cape manganese mine, Kwatani 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,” says Schoepflin. “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 metre double-deck scalping screen, a 3 metre double-deck screen, a 2,4 metre screen and a 1,8 metre dewatering screen. A leading local OEM that has designed and engineered vibrating screens for over four decades, Kwatani has built a reputation for world-class expertise and capability.

“Customers choose us for our engineering track record – developing technology that can manage the tonnages they require,” she 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, says COO Kenny Mayhew-Ridgers. He highlights that on-time delivery of a fit-for-purpose product is as vital as its reliable operation.

“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,” says Mayhew-Ridgers.

This is particularly demanding as custom-designed equipment undergo an intensive design process after being verified by rigorous finite element analysis in-house. 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. 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.