EFFICIENT MOTORS VITAL FOR DESALINATION PLANTS

With concern growing that climate change will exacerbate South Africa’s vulnerability to drought, the country is likely to see more desalination plants being installed along our coastline.

Coastal provinces such as the Western Cape and Eastern Cape have been experiencing intense droughts in recent years, and about 10 desalination plants have already been built. According to Dillon Govender, Zest WEG’s public sector specialist, a key cost factor in these plants is the electrical energy required for the high volumes of water being pumped, as well as the volume and high pressure required for the reverse osmosis process, which is the most commonly used technology these days. 

“Desalination plants employ numerous pumps for various functions in the process – all of which need to be driven by electric motors,” says Govender. “The reverse osmosis system also requires relatively high pressures to be maintained, to enable salts to be removed through the use of semi-permeable membranes.”

Reducing the specific energy consumption (kwh/m3) is therefore a strategic requirement underpinning these plants’ viability and performance. WEG’s range of high efficiency motors are being employed across the complete range of desalination plant pump applications, he says. 

These include the intake of raw water (sea water) into the pre-treatment section for the first filtering, high pressure pumping through the reverse osmosis phase itself, post-treatment and storage, and the final pumping to distribution networks and facilities. 

“Our motors are also used for the pumping of concentrated sea water or brine back into the ocean,” he says. “Only about half or around 45% of the volume of the seawater entering the plant through the intake system actually leaves as potable water.”

To further enhance the efficiency of the pumping circuit, Zest WEG supplies gearboxes and variable speed drives (VSDs) with integrated PLCs. This optimises energy consumption while ensuring the required pressure and flow through the desalination membranes, as well as reliable performance in auxiliary systems such as backwashing, dosing, chemical cleaning and brine pumping systems. 

WEG’s Pump Genius software enables a standard VSD to be dedicated to specific pumping systems with various motor and pump combinations, thereby providing improved control and monitoring capability as well as maximising energy savings and reducing downtime.

“We are able to design and supply the necessary electrical enclosures and motor control centres (MCCs) in low and medium voltages, as well as container-type electrical rooms,” says Govender. “Zest WEG also provides solutions for emergency power generation, power distribution and alternative energy generation. Using the Motion Fleet Management (MFM) tool, will also reduce operational costs for maintenance tasks.”

Due to the corrosive coastal environment typically associated with the location of desalination plants, the WEG high efficiency motors have integral IP66 protection, facilitating protection against salt water ingress caused by heavy seas and higher tides. Installation of heaters as well as the epoxy coatings of the motors, helps achieve greater longevity under these arduous conditions. WEG’s Variable Speed Drives (VSD) and soft starters are also available with IP55 ingress protection improving longevity, while all critical components within the VSDs and soft starters are covered with an additional anti-corrosive coating. 

He notes that WEG motors and other electrical equipment have been installed in desalination plants in African countries like Namibia, Algeria and Tunisia, and more widely in countries globally including Saudi Arabia, Bahrain, United Arab Emirates, Chile, Peru, Australia and Spain. 

CONSTRUCTION OF THE MEERKAT EXTENSION GETS UNDERWAY

Concor, the leading black-owned construction company, in partnership with OptiPower, is building the foundations and infrastructure for 20 more dishes for the pioneering MeerKAT radio telescope. A precursor to the Square Kilometre Array (SKA) – which will be the world’s largest radio telescope – the MeerKAT project has already allowed astronomers to deliver unprecedented results. 

Its remote location in an arid area about 90 km from the town of Carnarvon is perfect for its purpose, providing a ‘radio controlled ’ backdrop for the mid-frequency array that enables the SKA’s work. According to Concor contracts manager Stephan Venter, the team commenced with the construction works on site in September 2021.

“With the piling rig on site, October saw our first piles drilled and concrete poured,” says Venter. “Soft soil and sandy conditions require that the 20 foundations will be based on piles with a concrete cap; each of these foundations has eight piles of 750 mm diameter and between seven and eleven metres deep.”

He highlights that precision is critical to the foundation construction, particularly the positioning of the bolt cage onto which each antenna pedestal is secured. These have to be accurate within fractions of a millimetre, to avoid any deflection when the dish ‘looks’ millions of light years into space.

“In addition to the accuracy, the foundations must ensure that the antennas are able to resist the force of winds, especially as the dish has a wide surface area,” he says. “There is also no room for any vibration of the dish.”

The 1,7 metre-tall, galvanised bolt cages – constructed to specification locally – are carefully positioned on the blinding of the foundation cap before the rebar armature is assembled, the shuttering is installed and the concrete is poured. After the pour, the top of the bolt cage extends from the foundation for securing the dish pedestal or tower.

Among the specific challenges of this project is the strict requirement to limit any radio frequency interference (RFI) in the vicinity of the MeerKAT telescope array. The highly sensitive radio telescope equipment is designed to detect extremely weak radio signals from astrophysical sources, and can be easily damaged by RFI from vehicle electronics, cellular phones and a wide range of other tools and equipment. Concor’s offices, workshops and laboratory are therefore in Carnarvon, and site personnel must travel each day.

“We have tested and modified all our on-site equipment to comply with the RFI limitations,” he says. “This includes excavators, trucks, graders, compactors, telehandlers, water bowsers, TLBs and our specialised concrete batching truck.”

The Reimer concrete truck is a self-batching unit chosen to do the work of a conventional batching plant, which in this instance was not justified by the relatively small volumes of concrete required. With 19 mm aggregate and crusher dust transported from De Aar, cement from PPC and tested water from local boreholes, concrete can be mixed in the truck on each foundation platform. The 20 smaller, piled foundations each take 60 cubic metres of concrete, while the larger four foundations each consume 144 cubic metres. 

“We are also employing a recycler on this project to prepare the wearing course layer for much of the 40 km of gravel access roads,” says Venter. “This allows us to save water in this dry area, as the recycler introduces water into the layer and then closes it up – keeping the moisture in for longer.”

The machine can cover long, straight sections of road efficiently, preparing the way for the grader to level the surface before final compaction. Concor will also excavate and fill 70 km of trenching, for electrical and data cables to run from the antennae to the Karoo Array Processor Building (KAPB). The project is due for completion by September 2022.

SOUTH AFRICA AT FOREFRONT OF PDS AND CPS TECHNOLOGY EVOLUTION

Proximity detection systems (PDS) or Collision Prevention Systems (CPS) have come a long way in the  last decade, with South Africa‑based Booyco Electronics at the centre of key technological advances. 

“When we were established in 2006, PDS was an exciting technology helping address mining companies’ heightened concern with health and safety – arising from incidents of collisions between vehicles and pedestrians on mines,” says Booyco Electronics CEO Anton Lourens. “Our equipment began as essentially a pedestrian detection system only, but has fast grown into much more powerful solutions for mines.”

PDS offerings have also become more than just a range of disparate product lines from various producers, he says. Rather, the whole field is now increasingly integrated into global efforts to enhance interoperability – in the interests of applying PDS and CPS solutions more effectively on various mobile equipment and trackless mining machines.

“We began by developing a very low frequency (VLF) solution for underground operations, as this technology was based on a magnetic field that could travel through the rock between tunnels or haulages,” he says. “Initially, our CWS500 system – focused on ‘collision warning’ – would simply alert the operator that there was a pedestrian located in a potentially hazardous position, close to the machine.”

As this technology rolled out to the industry, it quickly became clear that customers were looking for more functionality. This led Booyco Electronics to develop the next level of PDS – the CWS800 range that included vehicle-to-vehicle interaction. The company’s first five years saw the rapid evolution of features on the CWS hardware platform, including the addition of global positioning system (GPS) technology to make it applicable in surface mines.

“This also created the basis for us to develop the ground-breaking CWS900 system in 2010, which went beyond being a warning system to actually stopping a vehicle automatically in the event of danger,” he says. 

“This opened the door to developing ‘collision avoidance’ systems, and was a breakthrough in terms of our ability to begin meeting the Level 9 requirements of best practice as formulated by the global Earth Moving Equipment Safety Round Table (EMESRT).”

EMESRT is a global initiative involving major mining companies including Anglo American, BHP, Glencore and Rio Tinto. It engages with key original equipment manufacturers (OEMs) in mining to advance the design of equipment to improve safe operability and maintainability. Booyco Electronics has been integrally involved in EMESRT initiatives from as early as 2014.

“South Africa had also been leading the way with safety legislation, which encouraged the take-up of PDS technology in our local mining sector,” says Lourens. “This placed the country’s PDS suppliers in a good position to put equipment into action in the field, and to continuously improve our solutions in response to real-life mining conditions.” 

Working with EMESRT and Minerals Council South Africa, Booyco Electronics was also the first supplier to validate its equipment through the agreed simulation model developed by Vehicle Dynamics Group at the University of Pretoria. This independent verification process was an important step in the PDS and CPS development, creating a quality benchmark against which all the market players could be assessed. 

Progress in technology continued apace, with Booyco Electronics further evolving its hardware platform to new levels of stability and maturity, Lourens says. 

Booyco Electronics’ CXS solution is now software-driven, allowing even more flexibility and adaptability to customer’s specific needs. “This is another step-change for the technology, as we can keep up with fast-changing industry requirements without replacing our equipment,” he says. “The modifications can be made in the software rather than the hardware – and updates can usually be done wirelessly on site.”

Among the company’s over 100 mining customers in South Africa alone, Lourens highlights that each site has its own functional requirements, with some sites having more than one set of parameters. The way of the future, then, is software-based flexibility, so that mines can improve their requirements over time without having to change their installed PDS equipment. 

Building on VLF

Very low frequency (VLF) technology allows for a magnetic field to be created around trackless mining machinery underground, which will detect a pedestrian standing too close and will alert the system. VLF’s long wave-lengths can travel through rock, so can detect a pedestrian even when the operator cannot see them. 

Booyco Electronics developed its first proximity detection systems (PDS) from this technology, creating an electric ‘fence’ around a vehicle. An alarm is triggered when a pedestrian breaks the boundary of this magnetic field.  

The physics of VLF is a well-established area of science and industry; it was an important aspect of submarine development, allowing these craft to communicate while submerged under water.

WHY PREDICTING CHUTE LIFE IS SO IMPORTANT

Measuring the wear life of a transfer chute is no simple matter, as many different components need to be tracked. However, the benefits of doing this add directly to the bottom line through improved uptime.

Izak Potgieter, ISO systems manager at Weba Chute Systems, highlights how the company’s customised reliability model can capture key wear indicators for each chute – and calculate how much longer each liner, lip or other component will last. 

“By feeding the model the right data – including wear measurements taken during regular inspections – plant operators gain valuable insight into wear patterns,” says Potgieter. “This information can be used to predict which components need replacing, and when.”

This allows the necessary planning to be done, such as ordering the required parts to be ready on site for the next maintenance opportunity. This preventative maintenance ensures that there are no unexpected stoppages – with the related disruption and lost production time. 

“Our ability to accurately predict the lifespan of the components inside our chutes streamlines the whole maintenance process,” he says. “We use this reliability tool extensively on all our maintenance contracts, but even those customers without such contracts can still request the service from us.”

With reliability modelling, customers can receive a monthly report that will provide a timescale of when maintenance is needed on each of the wear parts within every chute. The complexity of the model reflects the differential wear levels in parts of the chute where impacts vary – so that owners can focus on areas of highest wear. 

BIGGEST SYKES PUMP YET FROM INTEGRATED PUMP RENTAL

In another milestone for southern African Sykes distributor Integrated Pump Rental, the company recently delivered its largest unit to date – a Sykes MH300 pump with stainless steel pump end was built at the company’s Jet Park facility

Driven by a Kirloskar DV8 engine, this auto-prime Sykes pump unit was fitted with a custom engineered fuel tank and skid, according to Steve du Toit, rental development manager at Integrated Pump Rental.

“The sheer scale of the project is demonstrated by the unit’s final dry weight of about 8 tonnes,” says du Toit. “Measuring nearly 7 metres long, this pump set is 2,5 metre wide and 2 metre high.”

With a pumping capacity of 500 litres per second at a head of 40 metres, the Sykes MH300 has been delivered to a customer in the mining sector where it will dewater an open pit to ensure that no flooding occurs during the rainy season. The presence of abrasive particles in the water required that the inside of the pump be coated with tungsten, while the stainless steel wet end would resist acidity.

“Effective dewatering demands that you don’t just keep up with the required volumes, but that you keep ahead of them,” he says. “For this application, there was no better pump than this one.”

The Sykes MH300 is the top of Sykes’ medium-head range, with a 300 mm – or 12-inch – suction or discharge. This compares with the 6-inch suction of the well-known Sykes CP150 model popular among contractors. A generous 3,000 litre fuel tank was included in the design to allow for long running time, and this reduces the monitoring and refilling necessary by mine personnel. 

Built in less than two months at Integrated Pump Rental’s modern facility, the pump’s vacuum capabilities were extensively tested in-house before delivery. 

“The pump was built for plug-and-play on site, with an auto-prime function for added ease of use,” du Toit says. “Supplied with the necessary pipework, it can be easily connected and immediately operated.”

Du Toit highlights that Integrated Pump Rental also conducts project work in addition to renting and selling its locally built pump units – providing a one-stop shop for customised pumping solutions.

MAKING PERVIOUS CONCRETE EASIER TO TRANSPORT AND PLACE

A stabiliser specifically designed for pervious concrete, CHRYSO® EasyDrain  is perfectly adapted to concrete with low fluidity.

This technology eliminates the constraints traditionally associated with batching, transporting and placing of pervious concrete, while improving performance and quality. By controlling hydration reaction, CHRYSO® EasyDrain extends the workability of concrete, while also fluidising the pervious concrete to facilitate its placement. 

Key benefits to customers include improved cost effectiveness, as trucks can be loaded faster to full capacity making transport more affordable as well as reducing the CO2 footprint associated with the delivery of concrete to construction sites.  Concrete is also easier to handle and place, being more fluid and homogenous. In addition, there is greater durability, with less risk of cracking and aggregate ravelling. 

CHRYSO® EasyDrain allows customers to take full advantage of the outstanding qualities of pervious concrete, which are its high performance and high drainage capacity of rainwater. 

As well as achieving full truck loads, concrete suppliers can discharge concrete trucks faster with no need for water reducers or cohesion agents. Contractors enjoy the faster discharge and easier placing that CHRYSO® EasyDrain  provides as well as the improved surface finish that is possible with high workability. Contractors can also install curing membranes quicker and significantly reduce associated costs that includes time and labour cost benefits. 

Project owners in turn will appreciate the greater drainage that their pervious concrete achieves, along with its enhanced aesthetic finish and improved durability. 

CHRYSO® EasyDrain can contribute to a wide range of pervious concrete applications, including light traffic roads, car parks, terraces, garden paths, swimming pool surrounds, cycle paths and pedestrian ways. 

The CHRYSO® EasyDrain solution involves specific concrete mix design criteria with the use of complementary admixtures that improve the quality and performance of pervious concrete. 

Project reference includes the WBHO Vlakfontein reservoir project where the use of CHRYSO EasyDrain was specified to improve the quality of pervious concrete. Several other admixture solutions were also supplied by CHRYSO  to this project site including CHRYSO Serenis (shrinkage reducing admixture) and  CHRYSO CWA 10 (crystalline water proofing admixture) as well as CHRYSO Omega 178 new generation admixture to improve the water reduction properties as well as achieve the concrete strength requirements of the specific concrete mix design.

SUPERVISORY LEADERSHIP HOLDS KEY TO SAFE MINING

While leadership development at the top management levels of the mining sector tends to be well-researched and better resourced, there is a burning need to build the capacity of the industry’s supervisory levels.

This is according to Tony Pretorius – Education, Training and Development (ETD) Executive, Murray & Roberts Cementation, who unpacked what this means in real terms for the mining industry. 

“This is particularly important in the arena of safety, where significant gains can be made if production teams are imbued – through good leadership – with a daily commitment to safe working practices,” Pretorius explains. “It is clear to most forward-thinking businesses today that organisational culture underpins positive results; as importantly, it is also accepted that such a culture must be driven by leadership.”

He says there can, however, be barriers to the effectiveness of leadership. This presents as a kind of ‘permafrost’ at certain levels within an organisation, and the quality of supervisory skills can be vital in preventing this barrier from forming. To help address this, the field of neuroscience has been one of the most exciting themes running through training and development in recent years.

Supervisory training programmes can leverage neuroscience by giving learners a better understanding of how the brain interprets the information it receives. It gives supervisors insight into how this information is ‘translated’ – based on how learners feel and on their level of emotional intelligence. It considers, for instance, the importance of personality types, their respective strengths and weaknesses, and the ways that negative emotions can undermine team performance. 

The next important step, he says, is to consolidate the value of this training into the organisation’s performance management system. This means refining key performance indicators to hold supervisors accountable. Such as approach ensures that new skills are applied and strengthened, rather than lost through lack of use, and can be measured by their impact in the workplace. 

“In many ways, performance management has been the weak link in the chain – although it is critical to changing the way that leaders behave. Only with this kind of change will industry see further improvements in operational safety,” he says. 

The role of senior management is, of course, an integral part of this journey to instil a culture of safety. In addition to the company’s interventions in supervisor development, Murray & Roberts Cementation is also working with the University of Pretoria to gear its top leadership teams for the Fourth Industrial Revolution, including a programme focused on human factors in safety risk.

Pretorius says that the honing of skills by both managers and supervisors has an added benefit: it leads to more fruitful engagement between these two levels, building the organisational culture and the way that key company messages find their way into behaviour patterns. 

“As a company, Murray & Roberts Cementation accepts that we work in a hazardous environment. However, we believe that zero incidents are achievable, as is zero harm. Safety is not just a priority but a value, and our focus is on empowering people to manage risk.”

“In the end, safe production brings gains and efficiencies in time, cost and quality – giving companies a range of bottom-line benefits deriving from smooth operations and from delivering projects according to plan and specification,” Pretorius concludes. 

SPECIALISED IN-HOUSE SKILLS UNDERPIN ENGINEERING SUCCESS

Technical excellence in large diesel and gas engine component remanufacturing relies as much on top-class artisan expertise as it does on advanced and specialised equipment, says Andrew Yorke, operations director at Metric Automotive Engineering.

“This is why our ongoing investment in our people and their skills creates the real asset underpinning our technical capability,” says Yorke. “In the same way that we re-invest in our world class equipment, we are constantly upgrading our skill sets and empowering new employees.”

He highlights the vital role in South Africa’s economy for structured and closely supervised learning of trades, which Metric Automotive Engineering has been systematically conducting for decades. From the previous apprenticeship system to the current learnership programmes, the company’s technical staff have grown into demanding senior positions. They also then assume responsibility for passing on their knowledge to new learners. 

“We work closely with the Manufacturing, Engineering and Related Services Sector Education and Training Authority (Merseta) to achieve the required competency-based outcomes,” he says. “At the same time, our learning process aligns with our ISO accreditation to ensure that the expertise we generate is globally competitive.”

The training of new entrants through to journeyman status – or artisans – has been central to Metric Automotive Engineering’s business model since day one. The meticulous sharing of experience and skills from the company’s ‘custodians of knowledge’ has allowed a steady supply of committed experts to gain the best value from its leading-edge machinery. 

“Customers have always been able to rely on the quality of our workmanship, as the depth of our skills base allows us to apply all the necessary ISO checks for optimal results,” he says. “This is also the basis of our culture of quality, where each person on our workshop floor feels the pride of being part of a smoothly functioning environment.”

The learning process ensures that a wide range of skills is covered, giving each learner a rounded capability and an integrated understanding of the workshop equipment and processes. This contrasts with an approach that leaves staff overly focused on a limited number of tasks – restricting their growth and abilities. 

“Our multi-skilled approach rather gives our artisans greater variety and fulfilment in their work and career development,” says Yorke. “It also gives our workshop greater capacity to absorb high work-flows while still ensuring that customers receive high quality results.”

He notes the importance of technical trades like automotive machining in opening up career opportunities for young South Africans. School-leavers with science and mathematics at matriculation level can enter exciting careers through structured learnerships. Such programmes can provide skills of life-long value, as artisan expertise evolves over time to meet new equipment demands and sophistication. 

TRAFO MINI-SUBS & DRY-TYPE TRANSFORMERS TO MOTOR PLANT

An important expansion to South Africa’s automotive industry is benefiting from the installation of 10 dry-type transformers and two mini-substations supplied by Trafo Power Solutions. 

The units, for a motor plant near Pretoria, range from 315 kVA to 4 MVA and were custom designed and manufactured to the exacting requirements of the electrical consultants on the project, according to David Claassen, managing director of Trafo Power Solutions.

“Working closely with our customer to finalise the design specifications, as well as with our manufacturing partner TMC Transformers in Italy, we were able to meet the tight turnaround times,” says Claassen. 

He highlights that each of the transformers were required to meet particular design challenges. With the six 3150 kVA units and the 4 MVA unit, for instance, fault levels had to be kept to a certain predetermined maximum. The design parameters for the two 1600 kVA units had to ensure they could withstand a relatively high harmonic content.

“One of our strengths is being able to collaborate positively with both consultants and contractors in high pressure contracts like this one,” he says. “This allowed us to achieve the required designs within the strict schedules, so the end result would be fit-for-purpose and delivered on time.”

Trafo Power Solutions’ flexible and proactive approach allowed them to deliver fully on the project despite occasional disruptions related to the Covid-19 pandemic. 

Claassen notes that the company was able to engage with the customer face-to-face and through virtual platforms, as conditions required. The company also took responsibility for logistical elements of the contract.

“Like the rest of the world, South Africa faces various freight challenges since the outbreak of the pandemic, but our innovative strategies ensured that shipping and customs arrangements were closely managed so we could land the equipment as needed,” he says.

The air-cooled format of the dry-type transformers offers the new motor manufacturing facilities an environmental benefit insofar as there is no risk of oil leaks. The units are also low maintenance and have a high safety rating due to minimal explosion risk. 

HVAC EXPERTS OFFER MINES SMOOTH, RELIABLE OPERATIONS

Specialists in robust, custom-engineered air-conditioning systems, Booyco Engineering is now driving the expansion of its service offering in the mining sector following the proven success of its products in this demanding industry.

The company has been a leader in heating, ventilation and air-conditioning (HVAC) solutions for decades, supplying extensively to the rail, defence and mining industries. Booyco Engineering managing director Brenton Spies says the expansion of its mining footprint will help mines improve their vehicle uptime while further enhancing health and safety performance. 

“Keeping mine vehicle operators cool in the heat of a mining site is crucial to health, safety and operational efficiency,” says Spies. “Standard air-conditioning systems, however, seldom stand the test of time, leading to unexpected failure and unplanned downtime.”

Among the factors causing early failure are hotter-than-average ambient temperatures, high dust levels, heavy vibrations, shocks from uneven mine haul roads and long operating hours. Grant Miller, Booyco Engineering’s executive director, points to the danger of drivers working in an over-heated cab, should an air-conditioning system fail. 

“This is not only a danger to the health of the driver, but could affect other workers and infrastructure on the mine if the cab conditions cause the vehicle to be driven unsafely,” says Miller. “Fortunately, many countries including South Africa apply regulations to ensure safe working conditions – so an operator could be entitled to cease work if the cab becomes over-heated.”

The result is that a machine could stand idle, waiting for repairs to the air-conditioning unit while costing hundreds of thousands in lost production for the mine. He says there are two aspects to avoiding this risk: installing fit-for-purpose HVAC equipment on mining vehicles; and applying a regular and high quality maintenance schedule. 

“This is where Booyco Engineering has proved itself to our mining customers,” says Miller. “We engineer the HVAC solution to suit the miner or contractor’s application, and we ensure that the equipment is well maintained.”

The company’s design and support capability has been developed over more than 35 years, employing the latest software and specialised tools in its 3,000 m2 Meadowdale facility. Its technical support services allow customers to rely on Booyco Engineering for a planned maintenance programme for their HVAC systems.

“Few mining operations have the skills to conduct this specialised work professionally on a regular basis,” says Spies. “Where the mine is large enough to warrant an on-site technician or team, we can put that in place as part of a maintenance contract to ensure that all HVAC systems continue performing optimally.”

He says the company can also provide regular site visits to conduct inspections and maintenance, and has a roving team available for ad-hoc call outs. Booyco Engineering’s rich heritage in HVAC design and maintenance makes it the ideal partner for mines looking to ensure reliable and uninterrupted operations, he says.