Ensuring sufficient water storage capacity in mines’ process ponds is crucial for the optimal functioning of mineral treatment plants, and this means regular desilting must be conducted.

This is according to Lee Vine, managing director of Integrated Pump Rental, whose company is frequently called upon to urgently attend to process ponds that have silted up. 

“While too much silt in these ponds can disrupt plant operations, this situation also raises the risk of over-topping which can lead to costly environmental damage,” says Vine. “Our locally developed SlurrySucker system can readily address the problem, but it should not be left too long. Ideally, mines would have a pond monitoring strategy and a regular schedule for desilting operations.”

He highlights that fully functional process ponds are increasingly important elements of a mine’s water balance, as mines actively pursue water conservation efforts to make themselves more self-sufficient. Strategies include more reuse of mine water, so ever-closer management of water flows is necessary.

It is usually possible to observe the bank of silt building up once it fills about 40% of a pond’s volume, he says. This indicates that prompt action is required. 

“With our proven technology, the desilting is relatively straightforward and not labour-intensive. It can be conducted effectively by just a couple of operators with the required training,” he says. He notes that recovering the value of the minerals in the silt can often cover the cost of desilting, with many mines being designed to recycle the sediment back into their process plants.

Choosing whether to contract-out the desilting function or conduct it in-house will depend on each mine’s conditions and preferences, says Vine. Integrated Pump Rental can provide the desilting service on a turnkey contract basis or rent the necessary equipment to the mine. For some mines, it might make sense to invest in their own SlurrySucker unit.

“We work with customers to find the right solution, assessing their detailed requirements before making a proposal,” Vine says. “Where mines wish to conduct the work themselves, we can train their staff and fully support the equipment with prompt parts availability and all the necessary engineering and maintenance services.”


Establishing a strong local manufacturing base in South Africa has been integral to Zest WEG’s success over the past decade, building the economy and providing an important springboard into Africa.

This process has aligned closely with the strategic approach of Brazil-based parent organisation WEG, which prioritises its member companies’ capability, efficiency and innovation on a local level, according to Juliano Vargas, CEO of Zest WEG.

“This has required considerable investment in our local production capacity and skills base,” says Vargas. “The outcome to date has been very successful, with Zest WEG developing its local structure and supply chain , while working to world class standards and supported by WEG innovation.”

As an example, he notes that Zest WEG today achieves almost 90% local content capability for its transformers and more than 70% local content capability for other products such as E-houses and panels. These products form part of the company’s wide range of solutions, including electric motors, drives, switchgear, energy generation, electrical infrastructure, and generator sets, with different levels of localisation.

This locally developed supply chain delivers various benefits to customers, says Vargas. These include short lead times, as there is little reliance on Europe, China or the US for parts and components. 

“The impacts to our market are considerable, and we have more predictability and control of our supply chain,” he says. The company has embraced South Africa’s commitment to transformation, achieving Level 1 B-BBEE status and investing heavily in training and enterprise development. 

It helped that WEG is a member of the BRICS Business Council (representing Brazil), so it has over the years been able to engage with South African authorities about local content requirements and industry development opportunities.

“Our business – both in Brazil and South Africa – has put our weight behind economic empowerment and transformation, focusing heavily on local suppliers and local skills,” he says. 

Zest WEG’s investment in human capital exceeds the portion of payroll demanded by B-BBEE in local training. Among other initiatives is a bursary programme, and it will shortly employ its third electrical engineer from this scheme. 

Vargas highlights the powerful launchpad that this groundwork has created for growing the company’s footprint in Africa, where it also applies its local development philosophy by partnering with in-country Value Added Resellers (VARs). 


Simon Andrews, managing director at Sandvik Mining and Rock Solutions, is thrilled to announce that Sandvik AutoMine® and OptiMine® have been recognised by the 2020 Global Autonomous Mining Solutions Product Leadership Award by Frost & Sullivan.

Frost & Sullivan Best Practices Awards recognise companies in a variety of regional and global markets for demonstrating outstanding achievement and superior performance in areas such as leadership, technological innovation, customer service and strategic product development.

”Sandvik is the only mining equipment and solutions company that was awarded in our 2020 Class of Top 50 Digital Best-practitioners across the Industrial and Energy Space,” says Rohit Karthikeyan, Industry Analyst at Frost & Sullivan.

The AutoMine® system is an innovative automation solution that comprises AutoMine® Underground and AutoMine® Surface Drilling, enabling customers to scale up the mining automation at their own pace. 

The AutoMine® Underground product family includes the sub-products AutoMine® Tele-Remote, AutoMine® Lite, AutoMine® Multi-Lite, and AutoMine® Fleet. AutoMine® Surface Drilling is an automation solution available for a wide range of Sandvik’s iSeries top hammer, down-the-hole and rotary drills.

“One of the biggest competitive differentiating factors is that Sandvik is a mining equipment/mining process and digital solutions provider,” says Karthikeyan. “This expertise in technical, industrial and digital domains enables it to deliver compelling offerings that outperform peers’ products to the market.”

Riku Pulli, President, Rock Drills and Technologies Division, Sandvik Mining and Rock Solutions, says: “We are continuously developing innovative technologies that benefit our customers’ operations and this award indicates the success that Sandvik has achieved with our automation offering over the years.”


While it might seem at first glance that there is little to distinguish one transformer from another in terms of design and construction (other than size), the differences can in fact be substantial and potential buyers need to be aware that there is certainly far more to a transformer than initially meets the eye.

David Claassen, managing director of Trafo Power Solutions, says that in order to make an informed decision as to which product will best meet the needs of a particular application, the customer will need to look at several factors, including the ambient temperature ranges in which the transformer will operate, the expected core and copper losses, the load conditions and the ability of the manufacturer to test products in accordance with appropriate standards.

“The minimum, maximum and average temperatures in which a transformer can safely operate will affect the design and consequently the price of a transformer,” he explains. 

In dry-type transformers, two main temperature winding insulation classes exist – namely Class F and Class H. Class F allows the transformer to operate safely at temperatures up to 155°C without damage while Class H allows the transformer to accommodate temperatures up to 180°C.

Claassen says another detail to look out for is that both oil-cooled and dry-type transformers are available in multiple cooling options. 

“The most common is natural air (AN), where the surrounding still air is used to keep the transformer operating within the correct temperature range. The second most common option is the forced air (AF) method, which entails moving air over the radiators, or over the core and windings. This allows the temperatures to be kept in check,” he explains. Transformers using forced cooling are able to supply additional load over and above the nominal power rating but it is important to rate the transformer at AN (natural ventilation) and use the fans as a temporary measure. 

With regard to transformer losses, these comprise two parts – load or core losses and no-load or copper losses. It is important to note that there are IEC standards set up as to what the maximum allowable load and no-load losses may be. The higher the transformers losses are, the cheaper it is to produce and the operational cost will be higher 

Also important is the load that the transformer will supply (or be supplied by). Unfortunately, with today’s modern grid there is no such thing as a perfect load. Power electronics, as well as many other switching electronics, have contributed to non-sinusoidal waveforms, and hence harmonics. The Total Harmonic Distortion (THD(i)) that a transformer encounters significantly influences the design of that transformer.

Finally, potential buyers need to look carefully at the quality control programmes manufacturers have in place. These will ensure that at all stages of manufacturing all raw materials and components can be tracked. 


Variable ground conditions at an upmarket mixed-use development in Cape Town has demanded some innovative solutions from contractor GVK-Siya Zama Construction and readymix specialist AfriSam.

At the Old Cape Quarter project in De Waterkant, four floors of luxury apartments are being added to retail and office space. This meant substantial strengthening of the foundations and columns to accommodate the increased load, according to Garth Robb, contracts director at GVK-Siya Zama Construction. This was not a straightforward process, says Robb, with insufficient space in the basement areas for normal class 3 formwork. 

“We made extensive use of biscuit columns, where we added reinforcing around the old existing columns and core-drilled at an angle from above – adding grout to beef up the column sizes,” he says. “We core-drilled through the base to transfer the load onto the piling, with a number of columns and bases needing to be demolished and reconstructed.”

A key complication was that concrete could only be poured manually into the biscuit columns by wheelbarrow, through 60mm core holes from the slab above. Each column took up to an hour to pour, with admixtures accelerating the hardening rate of this highly fluid 60MPa concrete. 

“There was no option but for concrete to be delivered in smaller volumes, otherwise the concrete would harden in the trucks before it could be used,” he says. “AfriSam worked closely with us to find a solution, which was to deliver just one cubic metre of readymix at a time.”

Readymix trucks usually carry six to eight cubic metres, so carrying just a fraction of this had severe implications for efficiency. However, the situation demanded flexibility from both partners, says AfriSam territory manager Melanie Ross, and the needs of the customer had to come first. 

“Also, the pours could only start in the afternoon, and often continued beyond the 18h00 deadline agreed between the contractor and the authorities,” says Ross. “So extended permissions were obtained, and the AfriSam-contracted drivers agreed to put in the extra time until pours were completed.”

AfriSam supplied over 9,700 m3 of readymix to the Old Cape Quarter project, and about 10 different concrete mixes for different applications. These came from the company’s Woodstock plant about 8km from site and its Peninsula Quarry plant at Durbanville.


The astute application of digital tools is the key to continuously improving efficiencies on underground mines, according to Niel McCoy, business line manager for automation and digitalisation at Sandvik Mining and Rock Solutions.

McCoy says that the choice of digital tools needs to be based on each operation’s key performance indicators (KPIs). This is because the solutions that are implemented will be focused on monitoring and managing those KPIs. He then recommends a phased approach to introducing digital tools to an operation. 

“The starting point is always machine telemetry and basic production or productivity reporting,” he says. “From there, the solutions can be expanded.”

Sandvik Mining and Rock Solutions has extensive global experience in designing and implementing digital tools, including equipment health monitoring and process management. Its AutoMine® automation offering operates on 59 mining sites globally, while its OptiMine® suite of digital solutions is active on 66 connected sites. The ‘My Sandvik’ customer portal, a web-based digital hub, serves 214 sites and its Newtrax technology in wireless IoT connectivity is operating on 115 sites.

“Monitoring equipment health through My Sandvik Digital Services Solutions allows users to draw down telemetry data from their equipment in real time,” he says. “The data is automatically compiled into the required report format for quick analysis and response.”

The next aspect to be addressed is the actual management of the process being monitored, he says. This is where Sandvik’s Task Management and Scheduler – part of its Optimine® suite of digital solutions – can be applied. 

“This allows a tablet to be fitted to an item of equipment so that an underground operator can accept tasks and provide real-time progress reports on those tasks,” he says. “The more advanced the equipment, the more data can be extracted and communicated automatically without operator intervention.”

The solutions allow for data to be recorded on equipment’s key operations – such as the weight of loads in a loader bucket. Telemetry on the equipment gives valuable insights into the equipment’s availability and performance – so that management can respond. 

“When starting digital journeys, the focus must be on improving current operations,” says McCoy. “This means getting work started on time, for instance, before moving onto optimisation efforts. Most digital implementations will battle if the starting point is trying to increase productivity before getting the basics right.”


A Grundfos Hydro MPC-E booster pump set with four 7,5 kW motors and CIM 500 control system installed at the Hilton Hotel in Sandton is delivering both environmental and cost-saving benefits.

“The new energy efficient system has helped reduce our carbon footprint and combat climate change – an important part of our social responsibility,” says Charmaine Spasojevic, chief engineer at the Hilton Hotel.

Spasojevic says the cost saving will be achieved not only through the consumption of less electricity, but through reduced maintenance. This is due to the elimination of the separate variable speed drives (VSDs), meaning fewer items of plant to maintain. Management at the 12-floor, 329-room hotel will also have real-time access to operating data from the pump set. 

“The system integrates seamlessly with our building management system (BMS), allowing us full control over our service,” she says. The Grundfos CIM 500 control system allows the hotel to monitor various aspects of the pump set, including its running hours, energy consumption and discharge pressure, as well as any power supply problems or water shortages. 

According to Errol Dobson, Grundfos SA’s team leader building service, the Grundfos Hydro MPC-E maintains a constant pressure through continuous adjustment of the speed of the pumps. 

“The system’s performance is therefore adapted to the demand through the pumps being cut in and out as required, and through parallel control of the pumps in operation,” says Dobson. “Constant pressure control is also ensured through the continuous variable adjustment of the speed of each individual pump.”

The solution was designed and supplied in collaboration with Johan Truter, sales director at API Pumps Gauteng, and installed in June 2020. Grundfos service engineer Marius van Wyk commissioned the pump set, which will be serviced and maintained through a Service Level Agreement (SLA) with Grundfos.


Dry-type transformers supplied by specialist company Trafo Power Solutions are ensuring the safe and reliable operation of substations in a construction camp at a large liquified natural gas (LNG) project in northern Mozambique.

According to David Claassen, managing director of Trafo Power Solutions, 18 dry-type transformers were included in modular substations built in South Africa and shipped to site recently. The company is in a strategic partnership with leading Italian transformer manufacturer TMC Transformers, and is competing at the highest level with other global OEMs.

“These substations are for the project’s first construction camp of about 9,500 contractors,”  Claassen says. “Our transformers have been specially designed for the high ambient temperatures in northern Mozambique.”

Ranging from 500 kVA to 1250 kVA, the temperature of these units will rise to a maximum of only 80⁰C when under full load. With Class-H insulation on both the medium voltage (MV) and low voltage (LV) windings, they will withstand a temperature of 180⁰C. This is considerably more than the potential 40⁰C ambient temperature in the tropics plus the 80⁰C temperature rise. The transformers are also designed for levels of humidity up to 95%.

He highlights that the safety advantages of dry-type transformers allow them to be used in this application. As they do not contain oil – which is the usual coolant in conventional transformers – they pose no fire, explosion or environmental hazard. 

“A transformer containing oil would present a significant risk in a construction camp accommodating thousands of people in close proximity,” he says. “The safety level of dry-type transformers also means that they can be used in enclosed spaces like modular substations. The minimal maintenance required is an added advantage, being located on such a remote site.”

Claassen notes that the global competition to supply this mammoth project has been intense, and points to the vital partnership between the local knowledge and experience of Trafo Power Solutions, and the technology and expertise of TMC Transformers.