KWATANI SCREENS SUPPORT GOLDEN OPPORTUNITY IN NAMIBIA

Namibia’s bustling mining scene is seeing an exciting expansion and technological innovation at a leading gold mining operation, with Kwatani supplying five mill discharge screens – all custom designed and manufactured at its Gauteng facilities.

Kim Schoepflin, CEO of Kwatani, says her company has a long history in Namibia and a strong footprint across various commodities there – including an established presence at this gold mine. It has worked with the engineering, procurement and construction (EPC) contractor and the end-customer for two to three years on conceptualising the optimal solution.

“The mine is gearing up to increase its production by 50%, to take advantage of the strong gold price,” says Schoepflin. “Our role was to ensure that our discharge screens meet their exact process requirements – with our efficiencies of up to 95% – while delivering mechanical integrity for minimal maintenance downtime.”

The expansion includes the installation of two latest-technology mills – a high-pressure grinding roll (HPGR) and a vertical mill – which will boost production while reducing energy demand. Kwatani’s mill discharge screens, each measuring 3 m wide by 8 m long, will handle the coarse and fine material from the HPGR and the vertical mill. The company will also supply three silo feeders of 1,2 m by 2,5 m in size, to feed material from the silo to conveyors.

“Our screen design optimises the retention time on the deck, allowing for better screening and stratification,” she says. “Due to the volume of slurry and water sprayed onto the screens, the added retention time assists with better drainage at lower cut points.” 

The coarse screens were designed at a decline, and feature a larger screening media aperture with higher amplitude and stroke. Together with lower speed, this achieves better screening efficiency for the coarser particles. The fine horizontal screens, with smaller aperture screening media for the finer feed, were designed with a higher speed and lower amplitude and stroke; this will optimise the screening efficiency of the finer feed to these screens.

She also highlights the attention paid to the isolation of the vibrating screens. In this case, Kwatani engineers selected rubber buffers, which have higher dynamic loads but are more suited to wet applications and screens with a heavier mass.

“The number and type of buffers were defined according to the mass of the screens,” says Schoepflin. “The selection of rubber buffers for larger screens also assists with start-up and shutdown time, allowing the screens to come to rest more effectively.”

For these five screens, Kwatani designed and supplied custom counter-balance frames to minimise the dynamic load to the plant infrastructure. The company’s screen technology includes designing its exciters in-house. This ensures that screens receive the necessary G-forces for optimal material stratification and screening, matching customers’ process requirements with the best possible efficiencies. 

“To make sure our screens cope with the high capacity demands of modern processing plants, we rigorously test all units in our in-house testing facility before dispatch,” she said. “These units began their journey to Namibia at the end of November 2021, and our team will support the commissioning when the customer requires.”

CONCOR STARTS WORK ON FAST-TRACK STUDENT BLOCK 

Leading black-owned contractor Concor is hard at work on the latest student accommodation project in Braamfontein, Johannesburg – a much-needed contribution to the national shortage of these facilities.

The Groove, a substantial 13-storey development, will provide space for 899 students, and is conveniently located just opposite the South Gate of Wits University. Concor is working with developer Growthpoint Properties, who in turn is operating on behalf of Durban-based fund manager Vulindlela. 

In addition to the new build, the project is also repurposing some of the existing buildings on the site where the old Doves & Kloppers funeral parlour became a familiar landmark on the busy Enoch Sontonga Avenue. These existing buildings will provide additional services and utilities for student residents.

The fast track venture is scheduled for completion in just 12 months, according to Concor site agent MacDonald Ngobese, and began in November 2021. 

“Concor has a well-established reputation for delivering complex projects speedily and on budget, while still being highly competitive in terms of costing,” says Ngobese, “This places us in a strong position to win projects like this.”

He notes that the successful completion of fast track projects relies on having a highly skilled and experienced core team on site, to closely manage subcontractors and to keep strictly to the construction programme. This also requires constant and in-depth communication with all stakeholders, from the client to operational partners and local authorities.

“The scope of the work includes full fit-out, right through to joinery,” he says. “Among the challenges is the very constricted work environment, as the site borders busy urban roads and the M1 highway.”

Two of Concor’s tower cranes have been erected on site to help deal with space constraints and to expedite the movement of materials in the interests of a fast pace of construction. While one crane is working 13 hours a day on production work, the second is speeding up the off-loading and placement of material deliveries. 

WEIR MINERALS MARKS GREAT DECADE FOR WARMAN® DIRTY WATER PUMP

It has been 10 years since Weir Minerals Africa sold its first Warman® DWU (dirty water unit) pump, with the locally developed and manufactured innovation achieving success in Africa and abroad.

According to Weir Minerals Africa head of engineering Christian Stehle, the Warman® DWU pump was designed to fill a gap in the market between conventional slurry pumps and clear water pumps. It succeeded in combining the best of both pump categories, to create a product with the wear resistance and robustness of the slurry pump and the efficiency of a clear water pump.

“We wanted a solution that would meet the needs of customers who wanted to pump water with a specific gravity of up to 1.05,” says Stehle. “They usually needed to do this over long distances, and often with high heads.”

He notes that the Warman® DWU pump is able to deliver high performance along with energy efficiency and reliability, without being susceptible to high component wear rates and premature mechanical failure due to dirt levels in water.

The first unit was sold in September 2011 to a mining operation in the Limpopo province town of Phalaborwa, and delivered such good results that the customer went on to purchase more of them. As the Warman® DWU pump was marketed through the global Weir Minerals network, it has also established itself in markets as far afield as Canada. 

The range has been enhanced over the years on a number of fronts, including its materials of construction. It is now available in stainless steel and in other hard-wearing materials for acidic applications. Initially developed with the traditional gland seal arrangement, it now includes the mechanical seal and the centrifugal seal as options. 

Modern design tools have allowed a continuous improvement in the evolution of the Warman® DWU pump, he says. With the 3D modelling of complex shapes, as well as 3D printing technology, the application of Computational Fluid Dynamics (CFD) has enhanced progress.

“The success of this pump in as little as a decade is a testament to Weir Minerals Africa’s design and manufacturing capability, as well as our understanding of customer requirements,” he says. “We continue to work closely with customers, turning needs into solutions for a sustainable mining sector.”

CONVERTING DATA INTO ACTION 

Leveraging the powerful telemetry and data acquisition capability of its mining equipment, Sandvik Mining & Rock Solutions is rolling out its Remote Monitoring Service – which analyses data to optimise valuable uptime.

By translating vast amounts of data from underground mining equipment into actionable recommendations, Remote Monitoring Service can also reduce the cost per hour of production equipment, lengthen its lifespan and improve operator safety. 

According to Imraan Amod, business line manager services responsible for Southern African at Sandvik Mining & Rock Solutions, the innovative system effectively merges telemetry data from the equipment fleet with Sandvik’s digital and OEM technical expertise. 

“This includes a global pool of reference data and in-depth analytical skills, which combine to produce actionable recommendations for continuous improvement of mining operations,” says Amod “We know our equipment through and through, so we are uniquely positioned to maximise its productivity wherever our data analysis presents an opportunity.”

Sandvik data scientists continuously monitor and analyse the data points acquired from customers’ production equipment. They identify root causes for abnormalities and develop predictive solutions to increase the mean time between failures.

By monitoring and analysing machine data and operator behaviour, Remote Monitoring Service can answer important technical questions to help streamline operations. For instance, it gives insight into why one operator consistently achieves better productivity than another, or why a specific loader suffers from unplanned downtime more often. 

“An example of what Remote Monitoring Service offers is to avoid improper gear selection, which can easily damage power train components,” he says. “It can identify incorrect gear selection when driving uphill and downhill, utilising algorithms tailored to the conditions at the customer’s mine.”

Another scenario is premature engine failure; Remote Monitoring Service uses a neural network to observe operational signals from the engine. This determines the possible defect before it leads to power loss and engine breakdown. 

“This is an attractive value proposition for mine owners and mining contractors, as it allows mean time between failures to be targeted and improved,” he says. 

In addition to technical improvements, there is also the bigger picture of stakeholder expectations. Emerging social investors and other stakeholders today expect results and transparency around decarbonisation and sustainability, not just financial performance. Remote Monitoring Service can identify opportunities for reduced fuel consumption – and hence less climate emissions – so that mines can focus their operator training accordingly. 

The service is primarily designed for underground mining, suitable for both large and small operations as well as all types of underground production equipment. Remote Monitoring Service does not require customers to invest heavily in IT infrastructure or associated resources. Rather, the service provides a high return on the initial investment along with short lead times and low risks.

TRAINING SUPERVISORS FOR A MECHANISED, AUTOMATED FUTURE

Smart mining is a key focal point of leading underground mining contractor Murray & Roberts Cementation, and its digitisation strategy is strongly supported by its approach to supervisor training. 

“The Fourth Industrial Revolution is having major impacts on how we mine, so it is to be expected that our training focus must adapt accordingly,” says Tony Pretorius, education, training and development (ETD) executive at Murray & Roberts Cementation. “To underpin our digital strategy as a business, our training is evolving in terms of its outputs and its methodologies.”

Pretorius highlights that technology is improving safety and productivity in mining by facilitating automation, through either line-of-sight or tele-remote operation of equipment. 

This is placing new demands on supervisors, in their task of influencing better team performance. The company is introducing a range of digitisation initiatives in its projects, including a condition monitoring system to track the monitor the health of trackless mining machines (TMMs).

“Supervisors today still need to manage processes, systems and schedules to meet their objectives,” he says. “In addition, though, they also need the capacity to interpret the wealth of data that digital technology produces.”

The Murray & Roberts Cementation Training Academy (MRTA) at Bentley Park near Carletonville prepares supervisors with a series of e-learning modules including TTM appreciation, supervisory soft skills, legal liability, and mine-specific standards and procedures. 

However, the programme becomes more innovative with the inclusion of its neuro-leadership component.

“This course teaches supervisors about various personality types, their respective strengths and weaknesses, and how the brain influences the behaviour of those personalities,” he says. “This helps our learners to understand the different approaches inherent in personality types, and to take these into account in developing their leadership skills.”

The training itself leverages the use of two-dimensional and three-dimensional animations in the classroom, as well as interactive touchscreens. Supervisors are also exposed to the virtual reality space, where they are required to identify workplace hazards and risks and apply measures to manage these risks. 

“Our virtual reality modules include waiting place procedures, entry examination and safe declaration, as well as emergency preparedness and survey,” says Pretorius. “This is followed by learning in the mock-up environment, where they perform marking on the 3D blast wall with laser technology, and also sequential firing and blast advances.”

ENVIROTECH® PUMPS POPULARITY CONTINUES IN AFRICA 

Underpinning the popularity of Envirotech® pumps is Weir Minerals Africa’s ongoing investment and support, as well as the pumps’ integration into various pumping solutions that the company offers.

According to Marnus Koorts, general manager pumps at Weir Minerals Africa, Envirotech® pumps are especially popular in the gold mining sector, where up to 200 of these pumps can be found on a single site. He says there are three ranges in the Envirotech® line-up, which Weir Minerals Africa acquired in 1994 and continues to develop and support. 

“The Envirotech C5 range of metal pumps has always been a favourite for dirty water applications, and is widely used in mine dewatering,” says Koorts. “Its high pressure capacity of 6900 kPa makes it ideal for high head applications.”

The Alpha range of Envirotech® pumps is rubber-lined to resist abrasion, while the Envirotech® ME pump with metal expeller and Envirotech® MG pump with metal gland are unlined. All the ranges benefit from ongoing research and development, and are available in the various materials of construction offered by Weir Minerals Africa. 

“When selecting and sizing their pumps, customers can choose from our range of metal alloys including our Ultrachrome and Hyperchrome alloys,” he says. “There is also a wide range of rubber linings on offer, from our R55 premium grade elastomer to butyl rubber formulations.”

The technology incorporated into Envirotech® pumps make them a valuable part of Weir Minerals Africa’s engineered-to-order solutions and pontoons, where they are integrated with other products like Linatex® hoses and Isogate® valves. Koorts also highlights that the company’s Synertrex® smart analytics platform can be applied to Envirotech® pumps, for remote monitoring of equipment health.

Among the most important aspects of its expertise that Weir Minerals Africa has applied to its Envirotech® pumps is its Wear Reduction Technology (WRT®), which gives them not only longer wear life but also higher operating efficiencies.

“Many of the Envirotech pumps are now coming out with WRT components as standard,” he says. “This delivers massive value to customers, as the energy saving from the high efficiency is substantial.”

In a recent highly abrasive application, the WRT® impeller in the Envirotech® pump delivered double the lifespan of a replicator’s impeller. More importantly, the Envirotech® pump consumed almost a fifth less electricity each year, saving the user many times more than the value of the component itself.

“We continue to evolve and upgrade the Envirotech pump range in the same way as all our products, giving customers a modern and responsive solution to their pumping needs,” he says. 

The Envirotech® pump range is cast and manufactured in South Africa, and supported through the company’s extensive branch footprint throughout Africa and the Middle East.

AFRISAM CEMENTS PARTNERSHIP WITH SPRINGBOKS

Leading construction materials company, AfriSam, is proud to announce that it has joined the Springbok family with a three-year partnership.  The company is also breaking new ground as the first in the construction industry and cement manufacturing sector to partner with the Springboks.

“We are delighted to welcome a new partner from a new sector of the South African economy into the Springbok family,” said Jurie Roux, CEO of SA Rugby.

“AfriSam is a long-established company whose products are literally part of the fabric of the country. Similarly, we aspire to make the Springboks part of the fabric of the nation as well.”

AfriSam has been a long-standing supporter of sports going back almost 30 years when it sponsored one of the oldest football clubs in our country –  Orlando Pirates. That sponsorship was done under our previous company name, Alpha Cement.  More recently AfriSam has also shown support for the Free State Cheetahs and the South African Football Association’s development programme, Ima Nathi.

“One behalf of the entire AfriSam team, I would like to express our excitement about joining the Springbok family.  As a proudly South African company, we are constantly striving to build and uplift our nation.  Forming a partnership with a team that has, over the years, demonstrated how rugby can unify and inspire an entire nation, came as a natural fit for us.  We wish our beloved national rugby team all the best and we look forward to “creating concrete possibilities” together.  Go Bokke!” said Richard Tomes, Sales & Marketing Executive of AfriSam.

“We’d like to thank AfriSam’s leadership and their entire workforce for their support for the Boks. It’s the support of proudly South African companies such as AfriSam, that provides the foundations on which we can build, in this case almost literally”, concludes Roux.

ZEST WEG DELIVERS ITS BIGGEST MOBILE SUBSTATION YET

Leveraging its considerable in-house expertise and local manufacturing capability, Zest WEG recently custom designed and manufactured one of the largest mobile substations ever built in South Africa. 

The 50 MVA mobile substation – destined for Guinea – includes a dual voltage rated mobile transformer produced by WEG in Brazil, according to Bernard Mitton, engineering team leader for integrated solutions at Zest WEG. The substation will be commissioned early in 2022.

“This is a full turnkey project procured by Robustrade in Dubai for the Utility Company of Guinea, called Electricité De Guinée,” says Mitton. “Our in-house team co-ordinated the electrical, civil and mechanical designs, as well as the engineering solutions for the customer.”

The full project includes three trailers of equipment, and allows the end-user to step down power from the main national grid at various geographic points as required. High voltage power is tapped from existing overhead line with a specifically designed and manufactured tee-off solution connecting the supply into the mobile substation, where it is stepped down from 110 kV or 60 kV to 20 kV or 30 kV depending on requirements. 

“From the 50 MVA mobile substation, the supply is then distributed to a 30-20 kV mobile switching station, containing an incomer and five feeders,” he says. “Mini-substations can be fed directly, or a cable can feed to a junction box in the field, usually where there is an existing cable in the ground.”

As part of the project, Zest WEG designed and supplied a cable reel trailer with all power and control cabling needed for the mobile transformer and mobile switching station. Included on this trailer are 30 kV field junction boxes to assist with the cable connection between exiting cables already installed and the supply cables from the mobile switching station. These boxes allow for up to three feeder cable connections. The advantage of this design, he notes, is that the junction box becomes a termination point. The termination ends of the on-site cable do not need to be redone, and all that is necessary is a bolt-on connection. 

“This mobile substation solution is suitable for both temporary and permanent installations, so it can be used in a range of applications,” Mitton says. “For emergencies, it can replace an existing substation transformer in the event of failure, and for standby applications it can handle temporary overloads at substations.”

It can also be put to use during routine maintenance, to manage the loads of existing substations being maintained, repaired or inspected. This minimises the delay in taking out the unit due to load and other system constraints. The mobile substation can even be used to provide power for large project sites or mining sites of high importance.

He highlights that the design and construction of solutions for mobile applications, including mobile generators, is one of Zest WEG’s strengths. The expertise and capability within the business allows these units to be custom-designed to suit customer requirements. In fact, none of the mobile solutions provided to date have been identical.

“We have acquired valuable experience from many years of designing, manufacturing and supplying mobile solutions in modular configurable designs – mainly for Africa and Latin America,” he says. 

“These are not off-the-shelf products, but are custom-engineered solutions to technically comply with user’s specifications, integral requirements, the operational environment, logistical requirements and the safety of the operating personnel.”

The mobile substation includes innovative design features such as the integration of several functions into a compact, modular design. New technologies such as hybrid circuit breakers have been employed, along with disconnectors, earthing switches, ring-type current transformers, inductive voltage transformers and surge arresters.

“All the functionalities are included in a single prefabricated solution, while space requirements for switchgear bays are reduced through high integration of components,” says Mitton. “The substation’s transformer was specifically designed and manufactured by WEG in Brazil for mobile applications.”

Other special features include bushings made of composite silicon rubber, as well as an advanced mechanical and electrical safety interlock system. The modular design simplifies on-site installation, as all equipment has been pre-fabricated, pre-wired and pre-tested before shipping.

“This enhances the reliability of the solution, which translates into high availability and less maintenance,” he says. “It also simplifies the transport, logistics and commissioning.”

The order for the mobile sub-station was placed just before the Covid-19 lockdown in early 2020, so the project had to be managed under challenging conditions. The factory acceptance testing of key components, for instance, could not be done in person due to travel restrictions – so this was successfully done through virtual platforms across different time zones. 

“All in all, we embraced the new communication technologies and proved once again that we could deliver to customer requirements even under unprecedented conditions,” Mitton says. 

“Being able to meet the stringent requirements of Electricité De Guinée, through close collaboration with the Robustrade team, ensured the project was a success, proving this solution suitable for use across the region,” he concludes.  

FULL STAINLESS STEEL PUMP SET FROM LOCAL SPECIALIST

Pump specialist and local Sykes distributor Integrated Pump Rental is breaking new ground for customers in corrosive environments, offering a pump solution that is built entirely from stainless steel.

According to Steve du Toit, rental development manager at Integrated Pump Rental. while the pumps themselves or pump components are commonly available in stainless steel, the market has not yet made something like this readily available.

“Our focus on specific customer requirements, built to order in our modern workshop, has led us to develop a fully stainless steel solution – from the tank and skid to the lifting frame and other components,” says du Toit. “We have seen a definite interest in the market for this build design, as customers see the value in having this corrosion resistant material in all aspects of the pump set.”

He notes that the initial interest has come from the mining sector, where mine water being pumped is often acidic. However, he expects further interest from the chemical and process industries where corrosive liquids are pumped and stored. 

“The design is based on our ‘total solution’ approach, where we consider the complete application and its challenges,” he says. “While the upfront cost of stainless steel is obviously higher, the value gained by the customer in terms of longevity and reliability far outweigh this.”

Among the applications is open pit dewatering where there are low pH levels in the water, as well as coastal applications where salt water and air cause rapid rusting of mild steel. Integrated Pump Rental has already successfully placed a stainless steel unit in a coastal application, where it is performing well.

“Different grades of stainless steel are used in the design, depending on which components have the most contact with the acidic medium,” he says. “A range of materials is therefore employed to suit each application, and to achieve optimal performance at the most competitive cost.”

This custom engineering is made possible by the company’s range of technical skills and specialist experience that resides in its people. This in-house expertise includes draughting, fabrication and pump assembly, making use of coded welders and qualified boilermakers. Depending on the application, the stainless steel build can be supplied on a road trailer or with a site trolley.

BOOYCO MOBILE HVAC SOLUTIONS ARE BUILT TO LAST

Available from Booyco Engineering is a range of mobile HVAC systems specifically designed to meet the tough conditions typically encountered in the African mining, rail and military sectors. 

The systems, which are ideal for off-road equipment such as dump trucks, drill rigs, dozers and excavators, are able to cope not only with the vibration and dust associated with off-road environments but also the very high ambient temperatures that can often be encountered in Africa.

“There is a misconception that our mobile HVAC solutions are over-engineered, making them more expensive than they need to be, particularly in comparison to the mass-produced systems designed for use in typical heavy goods vehicles (HGVs). But these vehicles seldom run off motorways and they are typically designed for cooler climates,” explains Grant Miller, executive director of Booyco Engineering.

Elaborating on Miller’s point, Booyco Engineering’s MD, Brenton Spies, notes that Booyco Engineering’s systems are rated for use at ambient temperatures of 45°C to 50°C while mass-produced systems tend to be designed for cooler climates where 35°C is seen as the maximum operating temperature. In order to eject this additional heat, larger components are needed, such as larger condenser coils and more powerful fans. 

To cope with rugged off-road conditions, Booyco Engineering’s systems utilise welded structures and use thicker gauge (2,0 mm) steel plate than competitor products which tend to rely on less-expensive pop-rivetted structures and much thinner steel or aluminium sections. As a result, Booyco Engineering’s solutions are far more durable and reliable.

To counter dust, Booyco Engineering often includes scavenger fans and HEPA filters to maintain the air quality inside cabins. In addition, the cooling fin spacing is larger than on conventional units to limit dust build-up, which – if unchecked – can quickly impair the cooling capacity of inadequately designed systems. 

Summing up the case for choosing a Booyco HVAC solution, Miller says it is not sensible to pay money for a lower cost system that will not work in demanding African conditions. “And if someone claims that a lower cost system is the same as ours, beware! If it costs much less, it is likely not to work – and it certainly won’t work for long!” he warns.