PUMP STATION FAILURE CALLS FOR RAPID DEWATERING RESPONSE

There was no time to lose when dewatering specialist Integrated Pump Rental took a call from a long-standing customer recently; a vital pump station had gone down and they needed help urgently.

“The customer’s pump station was being refurbished, and its two pumps unexpectedly went down,” recalls Andre Strydom, rental development manager at Integrated Pump Rental. “These pumps performed a critical function for the customer, maintaining a constant flow of 200 m3/h per pump – over a one kilometre distance.”

What was required was an urgent water bypass solution to take over this duty while the in-situ pumps were attended to, and the pump station refurbishment went ahead. Within a day of the customer’s call, the nature of the application had been assessed and the quotation sent out. This was quickly followed up with the despatch of Integrated Pump Rental’s dewatering solution to site, where its pumps were rapidly commissioned.

“Having taken the call on day one, we had the pumps selected, delivered, commissioned and operational by day two,” says Strydom. The solution included the deployment of two diesel driven Allight Sykes high head dewatering pump sets, providing bypass water lines. These rental pump sets operated 24 hours per day to maintain the required flow rate through these pipelines.

“One of our primary advantages is that we can react with speed to our customers’ emergency dewatering situations,” he says. “This is because we operate a large and varied fleet of diesel driven dewatering pump sets, which are capable of dealing with different sizes of applications – each with their own operational requirements and site conditions.”

He also highlighted the team’s depth of knowledge in dealing with dewatering applications and their technical expertise. This allows them to apply expert judgement in identifying the most appropriate dewatering solution.

In this recent application, the two high head dewatering rental pumps remained on site until the pump station was completed and commissioned. Allight Sykes dewatering pumps, such as those selected for this application, are well known for their performance, efficiency and reliability.

Over the years, Integrated Pump Rental has built a strong reputation for its 24/7 service to industry, delivered for 365 days of the year. Irrespective of the dewatering application, the company can offer an appropriate solution, he says.

“The team prides itself on being able to respond to requests from customers at short notice,” says Strydom. “We understand that most requests for dewatering pump rentals are urgent, so they demand a rapid response with a solution that matches the needs of the job.”

CONCOR HANDS OVER HIGH SPEED IKUSASA PROJECT AT OXFORD PARKS PRECINCT

Applying innovative construction methods and its well-established quality and scheduling systems, Concor has met another tight deadline with the handover this February of the Ikusasa building in Rosebank, Johannesburg.

The building – which features four storeys above ground and three basement levels – is part of the popular Oxford Parks mixed-use precinct in Johannesburg, and will be occupied by Anglo American Global Shared Services (AGSS). According the Concor site agent Warren Mills, the company’s core team was required to manage around 70 specialised subcontractors, ensuring the most efficient deployment of resources to meet the project’s demanding timeframes.

“Among the innovations we employed to cut the construction time was the use of larger foundation piles,” says Mills. “This meant that there was no need for concrete bases or excavating around each pile; instead, the design allowed the columns to be cast over the piles.”

Some 115 piles were cast, with columns spaced on an 8.4 metre by 8.4 metre grid to hold the suspended concrete slabs. By expediting this part of the contract, Concor could give early access to the wet trade contractors like bricklayers and tilers, as well as to the installers of the unitised façade panels.

“This allowed us to make rapid progress toward the external works and the internal fit-out,” he says.

Another innovation was to back-prop on just two levels rather than the traditional three levels. This also allowed earlier access to the lower floor plate, to initiate brickwork and ‘first fix’ services such as floors, ceilings, electrical supply cables and water pipes.

“The result was to facilitate beneficial occupation for the tenant, giving them early access in a phased approach to prepare the working areas with furniture and other fixtures in time for employees to start work,” says Mills.

The building’s four levels make up over 7 500 m2 GLA, while the three basement levels cover more than 10 300 m2. The structure consumed about 8 700 m3 of concrete and over 800 tonnes of reinforced bar.

In line with sustainable building practice, a priority on the site was reducing, re-using and recycling construction waste. This included separating waste at source, ensuring that rubble, wood, steel and plastic was sorted into dedicated skips. By preventing contamination of different waste streams, waste could be more efficiently and cost effectively recycled.

Ikusasa is Concor’s first 6 Star Green Star building in terms of the Green Buildings Council South Africa’s Green Star rating. In recent years, the company has completed a number of award-winning buildings in the Oxford Parks precinct.

LOCAL HVAC EXPERT WORKS TO GLOBAL RAIL STANDARDS

While Booyco Engineering has been designing HVAC systems for South Africa’s rail industry for over three decades, it has also been serving the world’s largest rail players for more than 15 years by meeting their exacting standards including design, development, qualification and documentation.

“Having developed HVAC systems for the defence and mining sector, we understand the requirements for designing and manufacturing products for harsh operating conditions,” says Grant Miller, executive director at Booyco Engineering. “Our customised HVAC solutions for the local rail sector were based on our proven expertise.”

About 15 years ago, the company raised the bar even further working with the large rail multi-nationals based in Europe, the US and China. Its local office of engineers and designers began aligning its engineering design and development processes with international rail industry standards.

“When South Africa’s rail utility started to move towards a more standards-driven approach, we ensured we were up to speed with all the standards and specifications that the world’s leading players required,” says Miller. “This meant that we were already familiar with the way of working required to meet  the demanding standards specified by multi-national rail companies.”

This includes conducting extensive vibration and shock testing, airborne and structure borne noise testing, electromagnetic compatibility (EMC) testing, and high and low temperature and humidity cycling testing specifically to the standards of the rail sector. To fully leverage its expertise, Booyco Engineering’s in-house resources include over R8 million worth of specialised Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) software for modelling factors such as the strength of components and structure-borne vibration.

“For instance, these tools allow us to demonstrate to rail companies that our HVAC systems will not transmit vibrations, which could create resonance in the train’s structure,” he says. “Our digital design verification using CFD and FEA allows us to ensure that the physical tests conducted are more or less a formality, saving both time and money.”

Among the global rail standards against which Booyco Engineering has qualified its HVAC products are EN14750 thermal comfort in urban and suburban rolling stock, EN14813 thermal comfort in driving cabs, EN13129 thermal comfort in main line rolling stock, EN61373 for shock and vibration tests, EN15085 for welding qualification, EN50155 for the electronic equipment qualification and EN50121 for EMC compliance testing, all of which are standards developed specifically for the rail industry.

Once the big global players could see the company’s level of professionalism and conformity with the highest standards, it was also asked to design a cooling tower for an electric locomotive. To date, it is the only South African firm which has successfully designed and manufactured this equipment locally, adding significantly to the railway’s South African local content targets.

“Stepping down and converting the catenary voltage in a locomotive generates considerable heat of up to 400 kW,” he says. “Our cooling tower design is capable of effectively ejecting that heat in a +50°C ambient through the radiators at an airflow rate of 10 cubic metres per second.”

He highlights that the cooling tower order was another important indicator of the company’s extensive local design and manufacturing capacity, placing it in a strong position to serve the country’s needs while meeting global industry standards.

INCREASED UPTAKE OF THE SANDVIK DD422I DEVELOPMENT DRILL IN AFRICA

As mines in Africa are constantly turning to modern technologies to run more efficient operations and improve safety, Sandvik Mining and Rock Solutions has seen renewed interest in its DD422i, the next-generation mining jumbo with the widest range of automatic drilling functions.

Having sold the first DD422i development drill in Africa to Black Mountain Mine in 2018, Sandvik Mining and Rock Solutions has seen a ramp up in sales in the past three years, with nine more units making their way onto local mining sites, averaging at least three machines per year.

Saltiel Pule, business line manager for underground drilling in southern Africa at Sandvik Mining and Rock Solutions, says the will be more than 10 units operating in southern Africa by the end of 2022. The Sandvik DD422i has proven to be a machine of choice for tier one mining contractors operating at high-production mines in South Africa, Botswana and Namibia.

“Traditionally, mines in Africa have always lagged behind their global counterparts in adopting new technologies,” says Saltiel. “However, the Covid-19 pandemic has accelerated the application of Fourth Industrial Revolution (4IR) technologies in the local mining industry, hence the ramp up in sales of the DD422i drill since 2020.”

The local mining sector, adds Saltiel, has in recent years started to witness increased digitisation of the work processes, as well as the adoption of automation and other innovative tools.

“The Sandvik DD422i made its global debut in 2016 as the founding platform of Sandvik’s next generation underground drills designed to meet the industry’s growing need for new 4IR technologies such as digitalisation and automation,” says Saltiel.

The overarching differentiator, says Saltiel, is the iSURE®8 software (Intelligent Sandvik Underground Rock Excavation), a computer programme for mining drill and blast process control. It produces all the data miners need for an optimal drilling and blasting cycle.

The recent Sandvik automation upgrade packages, the Teleremote drilling and drill bit changer, further enhance the Sandvik DD422i’s automation functions. Teleremote is a reliable and easy way to control the drill from a remote location.

Sandvik’s patented drill bit changer further improves drilling productivity by allowing the operator to drill a full round without leaving the cabin to change the bit manually.

“Another major talking point on the Sandvik DD422i is its high speed, made possible by the 25 kW RD525 drifter, the biggest in the Sandvik face drilling range. This is a significant improvement on the predecessor range’s HLX5 drifter, which offered 19,5 kW of drilling power,” concludes Saltiel.

CORRECT SCREEN MEDIA SELECTION IS KEY TO LOWERING TCO

Screen media is a critical part of the metallurgical process, and it is therefore essential that the appropriate screen panel or screen panel combinations are selected, not only to improve efficiencies, but also to lower the overall cost of operation.  

This is according to Gerrit van den Heever, sales director at Multotec, who says that when it comes to procurement of screen media, few end users, and their procurement teams, ever think about the bigger picture – total cost of ownership (TCO), which considers not only the initial cost of the consumable, but also the cost of operation and maintenance.

“Although a screen panel is a relatively low priced component in a processing plant, there is often a big focus on this cost, at the expense of TCO, which in my view is a flawed procurement practice,” he says. “Incorrect media selection can result in the screen not being able to handle the duty requirements. Consequently, the impact on the bottom line can be severe”

In a dense media separation (DMS) plant, the cost of the ferro silicone or magnetite is significant. Effective screening can result in improved medium recoveries and huge savings. The other obvious benefit to effective screening is the avoidance of valuable product losses.

A range of factors should be considered when selecting a screen panel for the application. One of the principle parameters is whether the screening application is wet or dry. “In a wet application, the supplier should establish whether blinding, pegging and scaling are a problem. In a dry screening application, check whether impact and pegging are issues of concern. These parameters are key in selecting the right material, with the relevant physical properties,  in which the screen panel should be manufactured .”

Different materials of construction need to be considered with the most appropriate being selected for a given application. The company has invested in a substantial range of material compound manufacturing capabilities to meet different customer needs. These include 21 different types of injection moulded polyurethane compounds, 17 types of hand caste polyurethane compounds, 17 types of compression moulded rubber compounds, and 18 types of injection moulded rubber compounds (e.g. fire-retardant)

All screen panels are manufactured with tapered, self-relieving apertures, resulting in the unrestricted downward movement of any sized particle, reducing pegging and blinding.

Rubber screen panels – which absorb impact, reduce pegging and blinding, and improve wear life in coarse and heavy-duty applications – are suitable for both high moisture and dry applications. Wedgewire screen media is suitable for filtration, solid/liquid separation, classification, dewatering and concentration in mineral processing applications.

“It is important to deal with a reputable screen media manufacturer that can assess these application requirements and recommend the most appropriate screen panels and screen deck configurations for the application at hand,” says van den Heever.

Not only does Multotec offer a variety of compounds, but also various aperture sizes and configurations  to meet different customer needs. Overall, the company has over 1 000 apertures available to choose from. “If we cannot assist a customer out of this range, we will tailor a solution to suit the application,” concludes van den Heever.

RAUBEX IN N3 COLLABORATION WITH AFRISAM

Keeping the goods flowing between the port of Durban and the powerhouse of Johannesburg has always been a basic pillar of South Africa’s economic life; current roadwork on this vital corridor is hoping to streamline traffic and boost trade.

Since April 2021, JSE-listed Raubex Construction has been active on a 4 km stretch from Dardanellas to Lynnfield Park. The project is a major overhaul of the road surface, with the addition of two – sometimes three – lanes in each direction. Bridges are also being widened and a completely new twin-spine, road-over-road bridge is going up over the R603 route.

According to Raubex contracts manager Abri Lubbe, the widening of the bridges at the Umlaas and Sunnyvale underpasses has been completed, as has an agricultural underpass. The work has included the construction of abutments, the application of precast beams, in-situ decks, balustrades and end-blocks.

“The twin-spine bridge at the Umlaas Road junction – which is a three-span structure – is underway,” says Lubbe. “Work began on this bridge in October 2021, and piling has been completed to allow for the foundations to begin; it is due for completion by the end of 2023.”

Roadwork on the southbound lanes is getting underway, says Thys Greeff, construction manager at Raubex, as the contraflow arrangement for traffic frees up this side of the highway for construction work.

“Excavation takes place to between 1000mm to 600mm, and this is filled with blasted material from AfriSam,” says Greeff. “The next level may comprise a 150 mm capping layer and a 300 mm G6 selected layer, followed by a 350 mm stabilised sub-base layer of crushed material.”

Roadstab – AfriSam’s specialised road stabilising cement – is being supplied in 50 kg bags to the Raubex subcontractor for adding to the sub-base layer. By the end of the contract, around 180,000 bags of RoadStab – or some 9,000 t – will be used.

The readymix supply will come from AfriSam’s nearby plant at Umlaas Road, says AfriSam regional sales manager Randal Chetty. More than 300,000 tonnes of construction material, including unselected fill, blasted G6 material and 20 mm aggregate have been supplied to date.

With the scale of the numerous upgrading projects on the N3 placing pressure on local suppliers, Chetty says AfriSam’s quarry at Pietermaritzburg will be able to provide back-up supply where necessary.

“Serving this project – alongside others in the area – demands meticulous planning to ensure that the required blue and brown material is always delivered,” says Chetty. “On the readymix side, for instance, we have already begun stockpiling the 20 mm aggregate and river sand, for when project demand is greatest.”

MILESTONE AT MSIKABA PROJECT WITH JACKING OF SOUTH PYLON LEGS

The Msikaba Bridge Project on the new N2 toll road between Port Edward and Umtata achieved an engineering milestone this month, as the legs of the bridge’s south pylon were hydraulically jacked apart.

The 580 metre long, stay cable bridge – which will span the 198 metre deep Msikaba Gorge – forms part of the N2 Wild Coast project being undertaken by the South African National Roads Agency Limited (SANRAL) and is under construction by the CME JV joint venture, a partnership between Concor Construction and MECSA Construction.

These two legs make up the first 20 metres of the inverted Y shaped pylon, says CMEJV project director Laurence Savage, and are built without any lateral support as free cantilevers. Once completed four lanes of vehicles and a pedestrian walkway on either side will pass beneath these legs at the start and end of the bridge deck.

“The jacking apart of the legs countered the bending moment at the bases of the cantilever legs,” says Savage. “In layman’s terms, the jacking eradicated the effect of the legs bending towards each other; as engineers would see this, the legs are effectively vertical due to the jacking process.”

The bridge includes two pylons that will stand 128 metres high on each side of the gorge; the pylons support the bridge deck using a network of 34 cable tendons strung through their upper reaches.

“These cables then run from the top of the pylons back into anchor blocks located 100 metres to the rear of the respective pylons,” he says. “Each of the four anchor blocks is made up of over 1,600 tons of structural reinforced and mass concrete and extend 17 metres – the equivalent of six storeys of a building – into the ground.”

He explains that the lateral support was installed on the sixth lift of the pylon structure, after 520 cubic metres of concrete had been poured to reach a height of 20 metres.

“Two sets of hydraulic jacks were installed in parallel to each other and a jacking force of 1,750 kilonewtons (kN) applied to the two pylon legs to counter the bending moment for the freestanding cantilever legs,” says Savage.

“To achieve the required force, the two 150 ton hydraulic jacks were loaded to 90 tons, developing a pressure of 41 megapascals (MPa). The jacking was done on 5 MPa intervals, and deflections of the structure were monitored using dial gauges and surveying.”

He notes that a key consideration was the punching force on the flat face of the pylon legs due to the jack load. This also dictated the size of the bearing plates affixed to the inside of the legs, enabling a dissipation of the force across the appropriate surface area. This avoided any damage to the structure due to loading of the concrete surface.

“The jacks only have a 50 mm stroke, which required the installations to be exact – as the 41 MPa pressure had to be achieved before the jack ran out of stroke length,” he explains. “The base plates were installed on the pylon leg structure with 29 mm non-shrink grout minimising the use of the stroke length.”

After the lateral support was aligned and seated, a grout biscuit was cast which served two key functions. Firstly, it absorbed any tolerances in the installation after the initial base plate installation and secondly, it assisted with the removal of the lateral support. Breaking out the grout biscuit released the pressure in the lateral support, once the seventh lift was cast and the legs permanently locked together.

“The temperature of the pylon structure and lateral support was measured to ensure an average of 22°C, to limit any unforeseen changes in force due to changes in the temperature during the construction cycle casting lift seven,” he says. “The lateral support was wrapped in a 25 mm thick thermal blanket to limit temperature change movements and any resulting changes in prop forces.”

The lateral support was locked into place using a two-part system: the locking ring on the hydraulic jack, and the locking ring on the super-shore jack housing. The preparation for the jacking took three months of planning and analysis, while the setup was conducted over nine days. The actual jacking process was complete in less than eight hours from commencement.

Savaged concludes that the total movement of the pylon after jacking totalled 23 mm at a force of 1,750 kN – which was within the design parameters. The casting of lift seven to lock in the release of the moment will be complete by mid-April.

VENETIA TRAINING CENTRE IMPARTS UNDERGROUND MINING SKILLS

One the challenges facing De Beers as it implements its US$2,2 billion Venetia Underground Project (VUP) in South Africa’s Limpopo Province is the training of its employees – and new recruits – to allow them to acquire the necessary skills to successfully transition from open pit mining to underground mining.

The VUP involves the development of one of the world’s most advanced underground mines. Highly mechanised, it will employ the sub-level caving method to mine up to 6 Mt/a of kimberlite ore to produce between 4,5 and 5,5 million carats a year of diamonds. Once the VUP’s ramp-up is completed, the underground workforce will number around 850 people.

While the caving method to be deployed at Venetia Mine is well established (De Beers used essentially the same method at its Finsch mine in the Northern Cape when it owned and operated it until it was sold in 2011), very few of its employees at Venetia Mine have any experience of it. Not only will they have to adapt to the very different demands of an underground mining environment as they transition to the VUP but they will also have to learn the very specific skills associated with highly mechanised sub-level cave mining.

To expedite the required training, De Beers has now commissioned a training facility at Venetia able to accommodate e-learning facilities for 65 learners and classroom sessions for 95 learners at any one time. The facility represents a total investment of R188 million. At its heart are five training rooms, all with video walls and servers, as well as sophisticated mobile machine simulators.

An underground simulation area will have an emergency rescue bay and control room able to replicate situations occurring underground that could require evacuation while a virtual reality blast wall will give trainees the opportunity to mark up and charge a face.

All training will be managed by a comprehensive training management system offering modules for self-paced learning. The system is integrated into the mine’s human resources information system.

The simulators – supplied by Thoroughtec – allow operators to be trained on the Sandvik equipment – primarily trucks, loaders, drill rigs and bolters – that has been selected for the VUP. Most of the machines are classed as ‘intelligent’, meaning that they can deliver data continuously to on-surface control rooms and can be operated remotely. The simulator training is complemented by a TMM (trackless mobile machine) mock-up area on surface. Trainees will spend 15 hours in the mock-up.

As a follow-up to the training received at the training centre, De Beers has partnered with mining contractor Redpath to further enhance the skills of TMM operators. A contingent of Redpath personnel – who will be on site for the next four years – will assist with skills transfer on some of the key mechanised equipment and ensure that safety and performance levels of operators are up to the required standards.

While the training centre will focus on imparting core underground mining and TMM skills to trainees, De Beers has also developed a training package which allows both technical and non-technical personnel to familiarise themselves with the sub-level caving method. The content has been converted and incorporated into the electronic learning platform.

The sub-level caving training material has been split into 10 modules covering, amongst others, subjects such as mine design and sequencing; drill and blast; cave propagation and subsidence; cave management; and caving hazards and hazard management.

The training centre and other training initiatives at Venetia Mine all form part of De Beers’ operational readiness framework, which is designed to facilitate a smooth migration from open-pit to underground mining in terms of people, processes and systems.

JOINT ACTION NOW URGENTLY NEEDED TO HALT CONSTRUCTION MAFIA

Years of disruption by construction mafias in the civil engineering sector are holding back South Africa’s recovery, and all parties now need to throw their support behind efforts to eradicate this criminal scourge.

Lindie Fourie, operations manager at the Bargaining Council for the Civil Engineering Industry (BCCEI), says the problem of intimidation, extortion and violence on construction sites has reached crisis levels.

“We are encouraged by President Cyril Ramaphosa’s recent announcement of a special police unit to deal with the construction mafia, but it will need all stakeholders to give active support if this effort is to be successful,” says Fourie. “The BCCEI has developed an action plan to address the challenges in the civil engineering industry and we are reaching out to other players to ensure our response is collaborative.”

Key aspects of the plan include working with stakeholders to effectively prevent interference in projects, as well as reacting proactively to instances of interference, she says. She commended the various government bodies, industry associations and professional societies who have spoken out against the construction mafia, and called on all players to join hands in their responses.  

“With our members being both employees and employers, we have witnessed lives being threatened, ransoms demanded and people kidnapped as well as jobs lost when these criminal elements target important civil engineering projects – most of which are state-funded,” she says. “With government working hard on its economic reconstruction and recovery plan, the country cannot afford its investments in infrastructure to be hijacked by local mafias.”

She highlights that the delays and damage caused is stalling government’s job creation efforts, as infrastructure works are among the quickest ways to stimulate growth. With Treasury’s budget under strain following years of low growth and the Covid-19 pandemic, it cannot afford the cost of infrastructure to be further raised by criminal intimidation of contractors.

“Government infrastructure projects all include a range of constructive transformation measures, which are dutifully applied by contractors who legally win these projects,” says Fourie. “Mafias are undermining these worthy efforts and derailing crucial improvements to our roads, water, energy and other infrastructure – and holding back government’s service delivery.”

LOW-MAINTENANCE OPTION FOR SA’S AGEING MINI SUBSTATIONS

As South Africa’s many thousands of oil-cooled mini substations reach the end of their operating lives, there is scope to replace them with a safer and more economical option, according to Trafo Power Solutions managing director David Claassen.

“These mini substations are located all along our urban streets, in shopping centres and around industrial areas – in close proximity to growing numbers of people,” says Claassen. “As municipalities struggle to maintain these properly, they pose an increasing safety risk and become more expensive to service and repair as they get older.”

He points out that oil-cooled transformers require regular testing and maintenance, including monitoring and replacement of oil at regular intervals to ensure effective cooling of the unit. Without this maintenance, the risk of failure or even explosion is raised.

“Dry-type transformers do not contain oil, being cooled by air moving over the components,” he says. “This is one of the factors behind the significantly lower maintenance required by dry-type transformers, which of course translates into substantial cost savings over time.”

The absence of oil makes dry-type transformers considerably safer, he explains, as indicated by these units’ F1 fire rating. This means that they are resistant to flammability, are flame retardant and generate no harmful emissions.

Having no oil as a coolant also makes dry-type transformers less risky to the environment. The risk of oil spilling from an oil-cooled transformer – which can lead to the contamination of land and water – requires the construction of a bund wall. The dry-type option needs little of this kind of additional infrastructure, and so is more cost-effective to install.

“Trafo Power Solutions has worked extensively with developers of high-traffic infrastructure like shopping centres, ensuring the highest level of safety in mini substations located in high-density areas,” he says. “We are well positioned to supply public utilities with the same benefits.”

He notes that municipalities’ financial resources to service and maintain substations are often severely stretched, so it makes sense for them to seek more economical alternatives. Dry-type transformers are almost maintenance-free, he explains, taking a considerable load off the owners’ maintenance duties.

“We custom-design our solutions for dry-type miniature substations to meet customers’ exacting requirements,” says Claassen. “This includes any variation of medium voltage (MV) and low voltage (LV) needs and specific switchgear as well as customised control and protection options.”

Trafo Power Solutions supplies miniature substations from 200kVA to 2500kVA – ranging from 3,3kV to 33kV on the MV side, and from 400V to 1000V on the LV side. These substations are rated up to IP65 ingress protection.