Monthly Archives: March 2021

Client Focus

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. 

Client Focus

FLSMIDTH HIGH DENSITY THICKENERS DOUBLE MINE OUTPUT

When one of the world’s largest copper and cobalt producers wanted to double its production rates, it chose FLSmidth to provide a thickener solution that included six of its proven high density thickeners. The order was placed in 2020, and delivery has been completed. 

The mine, located in the Democratic Republic of Congo (DRC), already had FLSmidth thickeners on site, and was satisfied with their performance. According to FLSmidth general manager projects and account sales Howard Areington, the company’s proposal for the mine’s expanded requirements was based on testwork to confirm the characteristics of the material that would be treated. 

“The tests confirmed that we could use a similar design to what we had installed on the mine some years previously,” he says. “This solution included six counter current decantation (CCD) thickeners and one pre-leach thickener, each measuring 31 metres in diameter.”

These units deliver high solids underflow to optimise the recovery of dissolved metals. In addition to the steeper floor slope, these FLSmidth thickeners were designed with a high torque ring gear drive design, with high tolerances that make for minimal maintenance over long periods of time.

“Our high density thickener design ensures consistently high underflow densities which allows the operator to sustain high production rates and better recoveries,” he says. 

These CCD thickeners are manufactured from LDX2101 duplex stainless steel. This provides mechanical benefits without compromising chemical resistance, allowing the mass of each unit to be reduced. The pre-leach thickener, which was not exposed to corrosive conditions, is constructed from carbon steel. 

“We also designed and supplied five impurities removal thickeners, which are high rate thickeners, also in LDX2101 stainless steel,” he says. “The sizes of these units ranged from 20 to 30 metre in diameter.”

Fabrication of the equipment was done in South Africa, while accommodating the demands of the Covid-19 lockdown, which required careful planning and flexibility. With components and platework delivered to site, the welding and construction was conducted by the mine with installation assistance from FLSmidth and its agent in the region. 

Client Focus

BOOYCO EXPANDS ITS COAL FOOTPRINT AS LEVEL 9 LOOMS

Coal mines were among the first customers of proximity detection system (PDS) specialist Booyco Electronics, and the company continues to grow its footprint in this sector as mines work towards Level 9 compliance.

According to Booyco Electronics CEO Anton Lourens, the scale of recent orders from underground collieries and opencast operations are testament to the company’s leadership in the sector. 

“We support an extensive population of our proximity detection equipment on trackless mining machines (TMMs) in coal mines, and expect to see enthusiastic take-up of our new-generation Booyco CXS product,” says Lourens. He highlights that the customer base includes not only the Mpumalanga coalfields, but also those in KwaZulu-Natal province – supported by the company’s network of branches including Witbank and Richards Bay. 

Regulations currently demand that any electrically powered TMM in an underground mine must be equipped with a PDS, but many coal operations have a combination of diesel and electric units. He emphasises that the regulatory framework will soon enforce Level 9 requirements – with more advanced collision avoidance capability – for both diesel and electric TMMs.

“We are working closely with many OEMs and mining customers on aligning and testing our respective equipment for Level 9 compliance,” he says. “It should be remembered, however, that the industry still has considerable work to do on the application of PDS technology to surface diesel TMMs, which pose a range of technical challenges.”

An active participant in the mining industry’s Earth Moving Equipment Safety Round Table (EMESRT), Booyco Electronics collaborates extensively with stakeholders to support mines’ safety and compliance efforts. 

“Coal mines have a key role to play in the testing and application of collision avoidance systems, as the industry upgrades to ever-more effective safety protocols,” says Lourens. “The Booyco CXS consolidates all we have learnt in our 15 years in business, taking that vital step from a warning system to a fully-fledged collision avoidance system.”

He highlights that the Booyco CXS retains the intrinsically safe technology of previous generations, making it more cost effective and generally easier to manage. “The common alternative to intrinsically safe equipment is for suppliers to add a flameproof enclosure to house the PDS, which tends to be heavy and impractical,” he says.

Another contribution to safety and productivity is the Booyco Electronics Asset Management System (BEAMS) – a central information hub for a mine’s PDS assets. Centralising information from PDS hardware and monitoring devices, BEAMS enhances operations by identifying patterns of unsafe behaviour that can be promptly addressed.

Client Focus

SLURRYSUCKER SUCCEEDS WHERE OLD METHODS FAIL

Integrated Pump Rental’s innovative SlurrySucker desilting barge is successfully cleaning a large process dam for a coal mine in Mpumalanga, after past attempts by numerous contractors had failed. 

The dam – at a mine in the Delmas area – measures a substantial 300 metres by 100 metres in size, with a six metre depth. It was unable to function effectively as it had become 90% filled with coal slurry from the processing plant. Ruaan Venter, rental development manager at Integrated Pump Rental, says the pond is also lined with a geomembrane to prevent the coal slurry from contaminating the groundwater.

“Manual excavation methods had been tried by previous contractors, but these could not efficiently move the required volume of sediment,” says Venter. “In fact, some attempts made matters worse by damaging the environmentally important membrane under the pond. In addition, extensive reed growth in the dam also hampered the desilting efforts.”

By contrast, the application of the SlurrySucker was able to meet the safety priorities of the mine while cost effectively removing the slurry. Operating the barge remotely from a defined distance away from the dam’s edge is much safer than having personnel or equipment on the dam itself, he says. Operators also use a buddy system with a harness for added safety. Extensive training of operators was also required by the mine before work began.

“We were able to float the SlurrySucker on those parts of the dam with sufficient water, while also employing hydro-mining on the drier areas,” he says. “This allowed our high-solids pumps to dredge quickly and cost effectively over the whole area of the dam.”

Two monitoring guns, each fed by a 7-bar high pressure discharge hose, are blasting the drier slurry towards the discharge point. Specialised pumps with chopper-impellers are employed, which can deal with the dislodged reeds without becoming clogged. After setting up on site in December 2020, Integrated Pump Rental is expected to complete the slurry removal process by the second quarter of 2021, says Venter.

Client Focus

RAISING BENEFICIATION EFFICIENCIES IN COAL

With South Africa now working hard to contain the cost of its coal-fired power generation, efficiencies are vital throughout the value chain – not least in beneficiation.

This means the continuous improvement in coal beneficiation technology and regular equipment upgrades in plants will become more important, according to MBE Minerals SA managing director Johannes Kottmann. With over a century of experience in the coal sector, MBE Minerals SA has built up a wide footprint of vibrating screens in Africa for sizing, scalping, dewatering and media recovery. It also provides destoning solutions to customers.

“Among the company’s innovations is the side plate mounted drive, a much lighter option to using vibrator motors,” says Kottmann. “The screens can also be supplied with vibrator motors if necessary, while resonance screens offer the added benefit of lower power consumption.”

All types of screening surfaces can be accommodated, with each screen incorporating mechanical design features such as vibration dampening, side plates, cross members and the appropriate feed and discharge chutes.

He highlights that MBE Minerals is actively engaged with developments in coal beneficiation technology through its international network, including the MBE Coal and Minerals’ Research and Development Centre in Cologne, Germany. 

“This centre consults with customers globally in terms of optimum processing solutions, with the support of an in-house laboratory and pilot test work facilities,” he says. The centre also offers customer training, which can range from general mineral processing to maintenance of MBE Minerals’ equipment. 

In addition to designing, engineering and supplying equipment, MBE Minerals conducts projects on a turnkey or EPC basis, he notes; the company can also operate complete coal processing plants. It is particularly well known for its BATAC® jig technology, which delivers high separation efficiencies and improved product quality, as well as high availability and throughput. This technology’s ease of operation, robust design and economical maintenance cost have also been important factors in its success.

The company developed the BATAC® jig to overcome the limitations of early stratification technologies, which achieved separation either by moving the entire jigging bed screen or through water pulsation generated in an air chamber beside the jigging bed. 

“The separation accuracy of BATAC® jigs is due to electronic control of the air pulse generator and sensing of the thickness and densities of the material layers being separated,” he says. The under-bed pulsated BATAC® jig has proved ideal for coarse applications from 150 mm down to fine coal in the 10 to 0,5 mm size range, with throughput rates of between 100 and 1,200 tph. 

MBE Minerals has also developed a reliable and economical solution in destoning raw coal – the ROMJIG® – which has produced impressive results in extensive testing around the world. It achieves an overall reduction in the stone handled, says Kottmann, and there are indications of a lower percentage of refuse in the washery feed.

“This allows costs to be saved in a number of areas, such as reduced wear on machinery and transporting equipment, less grain degradation, and less dust and slurry,” he says. “It also means that flocculation consumption is reduced, along with flotation agents in downstream fines recovery circuits.” 

The range of vibrating screens manufactured by the company includes dimensions up to 3,6 metres in width and 6,75 metres in length; they come in single or double deck configuration and with either circular or linear motion. They have been operating in the African mining industry for the past 40 years.

“We ensure that each application, whether greenfields or brownfields, is carefully assessed in conjunction with the customer, during a comprehensive engagement process to determine the optimum solution,” he says. Services available include detailed engineering, feasibility studies, raw material testing, financing concepts, erection and commissioning. 

Components – as well as automation and process control equipment – can be supplied and installed for complete plants and systems. Measures to modernise plants or improve capacity can also be proposed. The company’s scope of services includes personnel training, along with pre- and after-sales services and support.

Client Focus

CONCOR COMPLETES HIGHEST RESIDENTIAL BLOCK IN MOTHER CITY

Cape Town has just seen the successful completion by Concor of the tallest residential block in the city area – fronted by a carefully preserved, century-old façade onto one of the trendiest streets in town. 

The 16 On Bree project is remarkable not just for its size – it transforms an old two-storey block into a modern 38-floor luxury development – but its complexity. According to Concor Western Cape senior contracts manager Collin Morilly, an early challenge was the preservation of the fragile heritage façade.

“The 16 metre high wall was built not of concrete but of rock, clay and lime, so it needed very gentle treatment and firm support,” says Morilly. “We erected a specially designed structural steel brace that would support the wall and prevent any structural failure while it was cut free from the rest of the building, which had to be demolished.”

A concrete ground beam was also cast along the base of the façade to act as a counterweight and prevent any movement. As the new structure was built, it was stitched in with the braced façade until finally the brace could be removed. There were also three other heritage walls within the building – standing in a U-shape – which were preserved during the construction process.

“The project also had to be implemented in the highly space-constrained city centre, with busy roads on all boundaries of the site,” he says. “This meant there was almost no laydown area for materials and equipment, and we had to ensure an uninterrupted flow of vehicular and pedestrian traffic.”

This was a significant achievement given the scale of the project, which consumed 21,000 m3 of concrete, 1,650 tonnes of reinforcing bar and 650,000 bricks. The new height of the building required the placement of 40 concrete foundation piles. Tower cranes had to be carefully managed to lift and place materials, a task made more difficult by the high winds for which the Cape is known, especially in summer. 

“Then came the unexpected disruption of work due to the Covid-19 pandemic,” he says. “We were soon able to get back to work after the initial lockdown, but this required extra vigilance and discipline because of the number of workers in such a confined space.”

Having about 900 people on a relatively small footprint over multiple floors meant that Covid-19 protocols had to be strictly implemented, based on a thorough understanding by all employees and subcontractors of the infection risks. 

“Social distancing was a particularly onerous aspect for us to adhere to, as the nature of construction demands that workers operate in teams and groups,” he says. “For example, a team of tilers must work in an apartment together, but the regulated social distance must be observed. This required that fewer workers be allowed into an area, which reduced overall productivity.”

Nonetheless, work proceeded apace to roll out the apartments efficiently and to the highest standard of workmanship. Drawing on the expertise of its trusted subcontractors, Concor’s experienced supervisors kept a close eye on the pace and quality of work, with at least four foremen looking after each floor. 

“We run our projects according to our SANS 10400 and ISO 9001 accreditation, and this means close management of the quality assurance and quality control process,” says Morilly. “Our systems included the SnagR snagging software to accurately record and close out snags timeously, and the Synergy document control software to facilitate timeous issue of information, tracking and recording.”

The Finishes Matrices system was also employed, indicating the level and the apartment in which each of the trades should be working every day. 

The result has been an elegant structure gracing Cape Town’s city skyline, rising 120 metres from street level and comprising 380 upmarket apartments. The future may hold scope for further residential units, making use of space currently used for the parking areas. To make this possible, the parking floor-to-ceiling heights were designed to the same dimensions – 2,9 metres – as the apartment levels. 

Client Focus

CONCOR LEVERAGES GLOBAL STANDARDS TO LEAD IN MINING

Meeting international standards is not an end-goal but an essential step in continuously raising the performance bar, according to Concor Mining Services HSE & training manager, Neil Fourie.

With its quality, environmental management, and occupational health and safety management system certifications recently renewed, Concor has underpinned its world-class status, says Fourie.

“These standards represent the life blood of our business, as customers rely on our management processes to provide them with the highest quality of service,” he says. “Our certification in terms of ISO 45001:2018, ISO 9001:2015 and ISO 14001:2015 gives them the peace of mind that we operate a management system aligned to global best practice.”

He emphasises that a key element of the ISO standards is the principle of effective control and continuous improvement to company procedures and processes. 

“Each year that we operate with these certifications in place, our management system matures and improves,” he says. “This guides us into deeper levels of auditing, which in turn drives our efforts to become better at everything we do – including raising our productivity and compliance.”

Good systems provide a backbone for the business, he notes, allowing the management team to focus on the operations and on smooth implementation of projects. This is increasingly vital in a competitive market, where managers on site must be able to tackle their important tasks in a systematic and methodical fashion.

One of the certification requirements is that internal audits are conducted on a regular basis to determine the effectiveness of our systems. “The internal audits are conducted at various levels and this interaction with our employees also has its own benefits, according to Concor Mining Services quality manager, Liz Diederichs. Far from being simply administrative checklist exercises, internal audits create valuable opportunities for engagement, coaching of employees at all levels, raising awareness, and often with inputs from the auditees opportunities for improvement.

“On a quality management audit, for instance, we check that all systems on a project are understood, implemented and maintained, allowing us to give considerable support to site management,” says Diederichs. She highlights the collaborative culture within Concor Mining Services, where all the relevant personnel are involved in the audits and the formulation of procedures. 

“All activities and tasks are discussed in detail, ensuring that employees buy into the process of creating the procedures that ensure the best practice is followed,” she says. 

Fourie notes that having a well-entrenched integrated management system that is aligned to international standards streamlines project turnaround times. On every new site that must be established, clear guidelines are in place for starting up and operating, so everyone can see what needs to be done.

“This also makes it easier to on-board new employees and ensure that they become productive as quickly as possible,” he says. “This adds to our adaptability and agility on projects, enhancing our cost competitiveness, workmanship and reliability in terms of meeting deadlines.”

As managers, specialists and professionals move between sites where projects are already underway, they can also slot into the workflow more easily as the systems and record keeping provide a detailed picture of planned and completed tasks.

“Having our own system based on international standards improves our interaction with the client too,” he says. “It allows us to easily align to the client’s requirements, or to seamlessly apply our own world-class system without compromising continuity.”

Concor Mining Services sets well defined objectives and targets to include from strategic, operational and functional through to health, safety and environmental issues like energy efficiency, carbon footprint, and equipment maintenance. Applying its standards-based integrated management system, the company has over the past five years maintained a zero-fatality rate and a lost-time injury rate of 0,00%, he says.

Installation of LED lighting at company facilities and rain harvesting at engineering workshops are among the energy and environmental interventions, while improved maintenance has been extending equipment lifespan and reducing the carbon footprint. 

Learning from health, safety, environmental and operational incidents has been an important feature in the continuous improvement journey with in-depth investigations, root-cause analysis and corrective action helping to eliminate the causes of non-conformances. The integration of Concor Mining Services’ management systems allows this learning to be effectively shared across the organisation.

“Our formalised systems also allow us to better monitor, measure, analyse our processes and communicate the status of our progress to all employees, so that there is a good understanding of their contribution towards achieving our targets,” says Diederichs.

Client Focus

WEST COAST MINER INSTALLS SLURRYSUCKER FOR POND DREDGING

Following a successful one-week trial, heavy minerals company Tronox Mineral Sands took delivery of a SlurrySucker dredging unit from Integrated Pump Rental. 

The SlurrySucker will remove sand from the process dams near the Tronox mining operation on South Africa’s West Coast. This installation enhances the safety and efficiency of the dredging process, which previously had to be carried out manually by a team of underwater divers. 

“The pumping capacity of the dredging unit will ensure optimal operation of Tronox’s dams which need to be kept at the required storage volumes at all times,” says Ruaan Venter, rental development manager at Integrated Pump Rental.

The dredging unit will assist Tronox to regularly clean sediment from our process dams, reducing the risk of pump blockage or failure. This solution aims to provides rapid results on a cost-effective basis, while the remote operation raises safety levels. 

To withstand the corrosive effects of salt water, the SlurrySucker has been equipped with a stainless steel casing as well as stainless steel components including wear plates and impellers. The units were manufactured locally at Integrated Pump Rental’s facility in Jet Park, Johannesburg.

The SlurrySucker dredging unit comprises a floating barge with an electric hoist operated from the side of the dam. This ensures a high level of safety with the barge being operated remotely, including the lifting and lowering of the pump. At Tronox, the SlurrySucker is designed to pump 150 cubic metres per hour of sediment – with a solids content of 50% – back to the thickener in the plant.

“The electrically-driven unit also makes sure that there is no risk of contaminating the water in the dams with diesel or oil leakage,” Venter says. The compact unit is easy to transport between the dams requiring dredging, making for optimal usage of the equipment. 

With its local manufacturing capability and technical support offering, Integrated Pump Rental is well equipped to maintain the SlurrySucker out of its modern Johannesburg facility.

Client Focus

HIGH POWER GRUNDFOS CR PUMP HITS AFRICA

With the launch of the Grundfos XL CR 185 vertical stainless steel multi-stage pump, customers can achieve higher flow rates and delivery heads while still achieving optimal energy efficiency.

“This extra-large addition to our well-known CR range pushes the limits of pumping capability,” says Niren Rohanlal, Senior Regional Product & Solutions Manager – CBS Advanced Core & Systems – India, Middle East and Africa at Grundfos. The model’s maximum flow rate is 240 m3/h and it can generate pressures of up to 40 bar.

“The pump’s maximum head is a remarkable 400 m, which is roughly the height of the Empire State Building in New York,” says Rohanlal. “To reach these demanding heights, it can be fitted with an electric motor of up to 200 kW in size.”

He highlights that the design approach of this robust pump is based on reliability, quality and efficiency, aiming to ensure customers a significant cost saving in terms of energy consumption, maintenance and total cost of ownership. 

“In today’s modern economy, the focus is on energy efficiency and lower carbon footprint,” he says. “We provide our own highly efficient Grundfos-branded motors up to 22 kW, while the larger motors that we use with our pumps must be at least IE4 in terms of global efficiency ratings.”

The Grundfos XL CR 185 has wide application as a pressure booster in industry, mines and commercial buildings, as well as for water utilities requiring high pressure delivery. An important advantage of the vertical orientation of this pump range is its reduced footprint, he notes. Where numerous pumps are employed in pump stations, this smaller footprint means that floor area can be made more compact. This cuts the cost of civil works in the construction of these buildings.

“The basic modular design of the pump allows stages to be increased as necessary,” he says. “The reduced design complexity means easier access to components when servicing and maintaining the equipment.”

Each component in the pump has endured extensive testing, ensuring the highest level of quality and reliability in the final product. The Grundfos XL CR 185 model is manufactured by Grundfos in Denmark, says Rohanlal, where it is thoroughly tested before being dispatched to South Africa for the sub-Saharan African market. The local ISO-certified Grundfos facility in Meadowbrook east of Johannesburg locally assembles CR pumps up to the CR 155 model.

Client Focus

WEG TAKES SOFT-STARTERS TO NEXT LEVEL WITH SSW900 RANGE

The new WEG SSW900 soft-starters are the ideal choice for complete motor control and protection. These units allow quick and simple access to application information and configuration settings in any installation throughout a wide range of industrial segments where a three-phase induction motor needs to be controlled.

With its well-structured menu interface, the WEG SSW900 line gives users a new level of interactivity, including Bluetooth connectivity. These soft-starters provide event logs with dates and times, as well as a setup and programming assistance. The built-in bypass extends the lifespan of the units, optimising space and reducing heat dissipation inside electric panels. This built-in bypass functionality also extends throughout the WEG soft starter product range, up to 1400 Amps.

By allowing the smooth acceleration and deceleration of motors by controlling the voltage, soft-starters greatly reduce mechanical stresses on couplings and transmission devices during the start-up of a motor. In pumping applications, the smart control prevents water hammer and pressure overshoots in hydraulic piping. 

Available from Zest WEG and its network of branches and value-added resellers in current ranges from 10 A to 1,400 A – and for supply voltages from 220 V to 575 V AC – the WEG SSW900 soft-starters can operate at ambient temperatures of up to 55°C without current derating. They can substitute direct online starters or star-delta starters, bringing a range of benefits to the user’s application. These include savings in electricity, as well as greater protection and increased durability of the electric motor. 

Users also have access to diagnosis and fault history, and experience greater flexibility as the WEG SSW900 allows the installation of accessories in the application. Graphic monitoring and customisable main screens provide further convenience.  The monitoring functionality is also extended by a USB connector available on all standard products. This provides access free of charge to product software available on www.weg.net.