All posts by Coral Fraser

WEBA CHUTE MECHANISM SAVES COSTS, DOWNTIME AT DIAMOND MINE

Challenging materials handling applications are the norm for Weba Chute Systems, and the company’s recent solution at a diamond mine in Botswana tackled the issue of large particle sizes to ensure more uptime for the customer’s operation.

The mine had been faced with replacing transfer chutes almost every three months, as they could not withstand the arduous operating conditions. Run-of-mine material with lump sizes up to 1,200 mm is fed via an apron feeder onto a grizzly feeder, with the oversize material reporting to the jaw crusher.

The large size of the lump kimberlite in this application – as well as material being uncontrolled – posed an ongoing challenge to the transfer system. Another challenge in this primary circuit is that the conveyor receives material from the grizzly underpan and jaw crusher discharge, and lack of material control had resulted in high impact onto the conveyor belt. This damaged the conveyor and caused considerable spillage, resulting in unplanned downtime as the conveyor belt had to be replaced just about every quarter.

The added expenditure and lost productivity meant increased operating costs for the plant, and eventually led to a decision to address the total material transfer system. The technical team from Weba Chute Systems assessed the challenges being faced and, in close collaboration with the mine, engineered a material handling solution.

“With innovation as our watchword, we were able to apply our extensive experience gained over the past 34 years,” says Dewald Tintinger, technical manager at Weba Chute Systems. “Dealing with challenging applications – and in particular uncontrolled material flow – is something we are known for; we are often called in to assist plants where a standard one-size-fits-all solution has proved inadequate to their specific material handling needs.”

According to Tintinger, standard solutions for transfer points do not consider factors such as lump size and material velocity, or the general arrangement of the transfer point and the relationship between the equipment that feeds and receives material.

“Custom-engineered transfer points, on the other hand, are designed to deal specifically with individual materials handling applications,” he says. “They offer major advantages to a plant, but these often only become apparent after the basic chute systems have failed.”

In Weba Chute Systems’ purpose-designed solution for the diamond mine, the transfer chute that moves material from the apron feeder to the grizzly feeder incorporates an innovative patented mechanism that overcomes the challenges of handling the 1,200 mm lump sizes.

“An integral swing mechanism – engineered to guide these large lump sizes through the transfer point at a controlled velocity – reduces the impact on downstream equipment,” he says. “The next chute in the process flow therefore no longer has to deal with excessive impact, as this has been addressed through the swing mechanism in the first chute. The material then flows through the grizzly discharge chute and reports to the crusher.”

The combination of an engineered transfer point – with the swing mechanism in this position – has drastically reduced high impact and excessive wear previously experienced. The chute’s longevity has been dramatically improved, and has not required replacement since its installation over a year ago.

The grizzly underpan chute system handles lump sizes of minus 250 mm and has been designed to accommodate this material. With a drop height from the grizzly feeder to the conveyor of about seven metres – and with lump sizes of up to minus 250 mm – this could become a challenging transfer point.

“Applying an engineered transfer point solution here was critical to the success of this material handling operation,” says Tintinger. “The chute design accommodates the material flow in such a manner that it is absolutely controlled and excessive damage is no longer caused to the receiving conveyor.”

The crusher discharge chute is the final of the four engineered transfer solutions; while the same engineering principle as the third chute has been applied here, the drop is not as far. The combination of these two chutes has significantly reduced material impact onto the conveyor and has substantially increased belt life.

THE FUNCTIONAL HEAVY DUTY IMPACT TRAFFIC DOOR

Engineered not only for optimum durability and safety, the Apex SR 9000 heavy duty impact door manages to blend into any environment as a result of its sleek, modern design.

Wim Dessing, sales executive at Apex Strip Curtains & Doors, says this cost effective, insulated traffic door has found popularity in market sectors where dependable operation coupled with an attractive appearance is important.

“Locally manufactured by the company, the Apex SR 9000 door combines functionality with longevity and allows easy movement of pedestrians and goods,” Dessing says. “We find that customers often specify this particular door upfront.”

The door is manufactured from a 3 mm ABS skin which retains its physical properties down to temperatures of minus 40°C. The low maintenance skin is impervious to moisture, acids, petroleum products, animal fats, rodent, insects and salt solutions.

The door’s insulation characteristics are enhanced by its high-density, non-CFC urethane foam core. The patented honeycomb framework and flexible urethane foam insulation provide optimum stability and superior soundproofing qualities.

Standard vision panels, constructed from 3 mm clear polycarbonate sheeting, are available in a number of custom sizes and are scratch-resistant and UBC compatible for enhanced visibility. Windows can be mounted in various positions on the door, and double pane vision panels can be installed for use in refrigerated areas.

“Wear is always an issue on impact doors, and to prevent excessive wear on the perimeter edges the door panels are bull nosed with a minimum radius of 8 mm. This significantly reduces maintenance on the doors,” he says.

The Apex SR 9000 doors are mounted on an internal welded steel perimeter with corner gussets, using a CMI type ‘V’ gravity hinging system. Gasket keys are moulded in place and retain gasketing without the use of screws, rivets or other fasteners. High bumpers are also fitted to the door panel to further absorb impact from forklift trucks and carts. This also reduces stress on hardware and mount assemblies.

Dessing says the company provides a full technical advice service that assists customers to configure the best door for each application. In addition, installation support and prompt delivery times ensure that customer productivity is not compromised.

NEW B-BBEE PARTNERSHIP ELEVATES KWATANI TO 51% BLACK WOMEN OWNERSHIP AND LEVEL 1

As the most transformed business in its class of original equipment manufacturers (OEMs), Spartan-based vibrating equipment specialist Kwatani achieved Level 1 B-BBEE status in January 2019 by becoming 51% black women-owned.

According to Kwatani CEO Kim Schoepflin, the new black and female shareholding offers a sustainable partnership with entrepreneurial passion and a vision to create value; the total female ownership of the business has now reached over 63%.

“This level of transformation is of huge benefit to mines in terms of their compliance with the Mining Charter,” says Schoepflin. Kwatani now provides its customers the maximum possible procurement points with 135% of claimable spend. She explains that this is an enormous advantage for the industry as each Rand spent will also be fully recognised under the category of black owned company and black women owned company spend.

“The Charter also requires that 70% of mining goods procured by mines must be locally manufactured, and we rate strongly on this score.”

She highlights that Kwatani has been supplying the African mining industry with vibrating equipment for more than 40 years, with tailor-made products engineered and fabricated in-house to suit customers’ specific application and processes.

“We have invested significantly over the decades in our facilities and our staff, expanding our manufacturing capacity, technology and expertise to become world class,” says Schoepflin. “What differentiates us in the local vibrating equipment sector is that we are the only OEM that is completely independent of any overseas company. Our technology and products are South African, and we import very few components or material.”

Most of Kwatani’s raw materials are sourced from within 10 km of its headquarters in Kempton Park, and all key production processes are in-house. The company’s supply chain contributes importantly to its B-BBEE score and is actively fostered by working collaboratively with suppliers on their respective transformation efforts and by procuring from and supporting the growth of small businesses.

“This demonstrates our commitment to the local economy and to advancing business opportunities within South Africa,” she says. “It also allows us to control quality more closely, and to improve our lead times on the equipment we build and refurbish, while being somewhat shielded from fluctuations in the value of the Rand.”

She emphasises that keeping abreast of latest technologies has required the company to constantly upgrade skill levels through extensive training that optimises the value of its productive assets. As an independent OEM, Kwatani invests heavily in its own research and development into engineering technology and fosters the skills to apply this research in its value-adding products and services. It has also earned the ISO 9001-2015 quality accreditation, one of only 5% of South Africa’s manufacturing companies to achieve this to date.

“Our commitment to transformation extends to internship programmes in collaboration with universities to advance young black engineers, as well as a training and placement programme for disabled persons,” she says. “Our social contribution focuses on education, supporting black teachers in maths and science.”

MOBILE HOT-MIX-IN-A-BAG OVEN TRAILER COMBO OPTIMISES LABOUR-INTENSIVE ROAD REPAIRS

With the aim of assisting the Gauteng Department of Roads and Transport’s (GDR&T) Tswelopele Contractor Development Programme in the Tshwane region, leading local asphalt expert National Asphalt has developed a comprehensive solution that optimises labour in construction without compromising cost, quality and productivity.

The company is collaborating with Siyeza Consulting, one of GDR&T’s newly appointed consulting engineering firms working on the Tswelopele programme, exploring ways to boost service delivery on road repairs by maintenance contractors. This intervention will help ensure key GDR&T contractor/service delivery objectives and targets are met. These include optimum budget expenditure, local labour enhancement, accredited contractor training, skills transfer and mentorship to underpin quality delivery of all road maintenance services to the department.

According to Gerald Gundu of Siyeza Consulting Engineers, many of these contractors are focused on pothole repair work, edge breaks and minor patchwork, and there was a need to find a viable asphalt solution.

“The objectives of Tswelopele include increasing the capacity, equity ownership, sustainability and quality of the technical and business practices of targeted learner contractors,” says Gundu. “As part of contractor development, Siyeza Consulting Engineers asked National Asphalt to demonstrate its products and technologies which these contractors could use.”

An aspect of the Tswelopele initiative is to create labour-intensive techniques for road repair and maintenance. This is aimed at employment creation and upskilling small contractors who would start at a Construction Industry Development Board (CIDB) level 1 and complete the Incubator Programme with a CIDB level 4 status after three years.

The asphalt solution proposed by National Asphalt is LT40 – or ‘Hot-Mix-in-a-Bag’ – which offers contractors ease of use of a quality continuously graded low temperature asphalt but with results that compare with traditional Hot Mix Asphalt (HMA).

“National Asphalt LT40 has zero waste materials, cuts down on time spent in queues at HMA plants, or product loss arising from bad weather,” says Pascal Garrioch of National Asphalt. “It also improves contractors’ productivity, allowing them to proceed directly to site with all the tools necessary to begin work without delay.”

“Heating of material on site using the mobile oven trailer means quality asphalt material is readily available and on hand 24/7,” he says.

Conventional HMA needs to be applied at around 150°C and must be laid within a few hours of manufacture. National Asphalt’s LT40 can be applied at between 80°C and 100°C and can be reheated for ongoing use without compromising any physical or technical properties or benefits of the asphalt mix.

Garrioch emphasises that the product is perfect for edge-breaks, minor patching, pothole repairs and the reinstatement of trenches with the application process carried out in the same way as traditional HMA repair.

“LT40 is supplied in 25 kg bags, and is heated to between 100 to 110⁰ C in a specialised oven which is supplied on a custom-built trailer,” he says. “Once at the right temperature, the product is shovelled onto a wheelbarrow and taken to the repair site where it is placed in the prepared area, spread, levelled and compacted accordingly.”

Contained in sealed plastic bags, LT40 has a shelf life of up to 12 months, allowing contractors to purchase and store the product for use at their convenience.

“The mobile hot-mix-in-a-bag oven trailer is the latest innovative alternative technology for maximising labour-intensive construction methods with improved quality in the maintenance and repair of paved roads,” says Gundu. He notes that the construction method and benefits of the technology explored are being assessed for suitability to labour-intensive projects, along with suitable funding models that could facilitate its uptake by learner contractors and small to medium enterprises.

CONCOR BOOSTS SAFETY AND TARGETED ENTERPRISES IN EASTERN CAPE ROAD PROJECT

Safety of both pedestrians and motorists has been boosted by Concor Infrastructure’s rehabilitation of the R75 double-carriageway between Port Elizabeth and Uitenhage, while the project has had considerable positive spinoff for local small targeted enterprises.

The project, which began in May 2017, includes the implementation of various road safety measures on Section 1 – which stretches for 13 kilometres – of this well-used national route. According to South African National Roads Agency SOC Limited (SANRAL), between 6 100 and 7 100 vehicles travel northbound on this route each day, including about 500 trucks. At the same time, over 4,500 pedestrians use the road, almost half those being children. Previously, the road used to have some of the highest pedestrian accident numbers in the Eastern Cape.

Concor Infrastructure’s site agent on the project, Roy van Leeve, says there will be a total of some 70 to 80 small targeted enterprises working on the contract over its duration. Among the sub-contracting opportunities from the project have been the relocation and installation of traffic signals, the accommodation of traffic, construction of lane widenings, installing sub-soil drains, guardrails, gabions, precast retaining walls and anti-climb fencing.

“Targeted enterprises have also been engaged to provide concrete linings for open drains in the road median, and for concrete palisades, concrete surfaced sidewalks, road markings and road studs,” van Leeve says.

He highlights the support structures that Concor Infrastructure puts in place to transfer skills to the targeted enterprises. These assist these small contractors to build their capacity to become sustainable businesses.

“Our engineers on site have each been allocated a number of targeted enterprises to supervise and mentor,” he says. “Many of the newer subcontractors have not had to operate on our level of professionalism before, so they undergo a considerable learning curve when it comes to dealing with quality systems, or health and safety. We work with them to put various systems in place in their own businesses, so that they are able to operate more independently from us when they move off site.”

Each of the small targeted enterprises receives hazard identification and risk assessment (HIRA) training, as well as training on construction regulations and legal liability which they can apply to their own business operations. The mentoring role includes training the targeted enterprises in planning of activities, in generating daily costings, and in the procurement of their materials.

Another important aspect of each targeted enterprise’s development is that they will invariably leave the contract with a higher Construction Industry Development Board (CIDB) grading than they were on when they started work on the project.

“If a sub-contractor with a Level 2 CIDB grading gets work with us, the contract is set up so that they will progress to a Level 3 grading by the time they complete their work here,” he says. “This is all part of the major developmental agenda that is in place on this project.”

Another important aspect of the work that will benefit local targeted enterprises is the street lighting component, which is rolling out new street lights along the full length of the rehabilitated roadway. This involves the installation of about 25 km of electrical cabling, which will be encased in concrete.

“This activity has been set aside for women labour, including the complete trench excavations as well as the encasement and backfilling,” van Leeve says.

30% of the value of sub-contracted work is being directed to targeted enterprises, he says, with about a third of that going to women-owned businesses and a similar portion to youth-owned businesses.

As part of the local empowerment focus of the project, labour was recruited from the nearby residential wards to ensure that employment and skills training benefits were shared with local communities.

The current phase of the contract is due for completion in 2019.

Key project facts
By completion, Concor Infrastructure’s rehabilitation on this section of the R75 will have involved 15,000 cubic metres of fill, from both commercial sources and from bulk excavations on site.

A cement-stabilised sub-base layer – amounting to 56,000 cubic metres in volume – was applied to sections of the road, consuming 2,600 tonnes of AfriSam Roadstab. For the surfacing, about 93,000 tonnes of asphalt is being supplied by a Port Elizabeth-based supplier.

Some 16,000 cubic metres of concrete will be used by the end of the project, for installations including 17 linear kilometres of concrete sidewalks and 7 kilometres of concrete-lined drains in the median. The project also involves 4,4 km of subsoil drains and 4,4 km of concrete lined side drains.

As an important part of the safety-enhancing features of the work, there will be 45 kilometres of guardrails and 18 kilometres of anti-climb fencing along the route.

Concor Infrastructure’s commitment to safety is reflected by the achievement of 550,000 Lost Time Injury Free (LTIF) hours by the end of September 2018. High quality work is ensured by close monitoring and supervision, carried out through daily inspections and weekly audits. This has led to consistent client audit results on site of between 96 and 98%.

Ongoing skills development includes the opportunity for 10 civil engineering students to gain work experience on site, benefiting from the mentorship of Concor Infrastructure engineers while undergoing experiential learning in fields such as construction management and survey.

CONCOR COMPLETES ON SCHEDULE AT OXFORD PARKS

The visionary Oxford Parks development in Rosebank, Johannesburg, has seen its first building completed by Concor Buildings for the new head office of BPSA, one of the country’s largest oil companies. Significantly, the building has achieved a 4 Star Green Rating in terms of the GBCSA standards.

According to Chris Maritz, contract manager at Concor Buildings, the building is part of Phase 1 of the Oxford Parks vision, which will include three more office blocks and a hotel. Work began in August 2017 for client Intaprop, and BPSA staff relocated to the new space in December 2018. The tight schedule of less than 16 months meant careful planning, implementation and monitoring, with 300 to 350 employees and contractors on site at the project’s peak.

“This is the first building in a large mixed-use development that will roll out a substantial part of the residential area between Jellicoe Avenue and Bompas Road in Rosebank,” says Maritz. “The construction of this first part of Phase 1 comprises three basement levels of about 28,000 m2 and six office levels with a gross leasable area (GLA) of 8,100 m2, as well as 960 m2 of retail space on the ground floor.”

Concor Buildings was required by the client to take the building to tenant fit-out stage, and delivered complete office floors except for loose furniture and IT equipment. The handover of floors – as they were completed – began in October 2018.

The attractive wedge-shape design is notable for its stunning glass facades, created with 4,500 m2 of glazing. This design enhances the wellbeing of the building’s users allowing ample fresh air, particularly unimpeded access to external vistas looking east over Johannesburg’s treed suburbs and plenty of natural daylight.

To deal with the sun’s heat through the glazing without overloading the air conditioning system, a couple of innovations have been included. The first is a double-ventilation façade on the front of the building, involving two layers of glazing some 40 centimetres apart. The outside layer is open at the bottom and at the top, allowing air to rise and exit this vertical channel as it heats, sucking in cooler air at the bottom and keeping the building cool.

The second innovation is the installation of automated horizontal blinds which are linked to a weather station. Guided by the season and time of day, the angle of the blinds controls the entry of direct light into building, further promoting energy efficiency.

The main structure of the building – which consumed about 17,000 m3 of concrete reinforced by 2,100 tonnes of reinforcing – was complete by the end of April 2018.

Concrete for the slabs was pumped to the required locations, while vertical elements like columns and lift shafts were poured by bucket from a crane; from first pour to completion of the concrete works was just seven months.

Wet trades such as brickwork and plastering were mostly completed by the end of May, with some 780,000 bricks laid by the end of the project. Finishing trades were underway by June, followed by services installation on all the floors.

Being located directly above and near the Gautrain tunnel posed particular challenges for the design of foundations for the building’s basement.

“Foundations were not conventional piling and pile caps but were raft foundations due to the restriction zones working above the Gautrain tunnel,” says Maritz.

Adding to this complication were the highly collapsible soils which, in the case of rain, could have fallen into the foundation trenches. Given the large amount of steel reinforcing required in the raft foundations, the recovery of collapsed trenches could have become costly and time-consuming.

“Excavations started in August 2017, but we mitigated the rainfall risk by fast tracking this phase and we were able to complete the foundations almost a month ahead of schedule, before any heavy rains arrived,” he says.

Being a residential area, there was also a restriction on working hours due to noise, meaning that work had to stop every day by 18h00 and on Saturdays by 14h00. No work was permitted on Sundays.

“This made it necessary, for instance, to conduct our large concrete pours promptly in the morning, so that there was time to complete the slab before the end of the working day and limit the noise to floating activities,” he says.

Maritz emphasises that good planning, time sensitivity and efficiency were all the order of the day in keeping the project’s timeline on track. This included installing the glass facades in good time as several tasks, like finishing trades, could only be finalised when the building was fully enclosed.

ROBUST GRINDEX BRAVO SLURRY PUMPS OFFER WHAT AFRICA NEEDS

Tough operating conditions are the norm in the mining sector, and even more so when it comes to slurry pumping applications. If incorrect pump choices are made in these demanding applications it can lead to high maintenance and repair costs and even catastrophic failures.

Colin Adams, managing director of Integrated Pump Technology, says the company often receives enquiries from African-based mining operations who have already made the mistake of not specifying high quality OEM products.

“Slurry pumps need to be up to the task of handling high volumes of abrasive material, and when this is not the case these failures lead to costly production downtime with the obvious knock-on effects,” he says. “For a number of years we have been cautioning the market and urging mine operators to carefully consider the overall total cost of operating slurry pumps when making decisions on which units to install.”

Integrated Pump Technology is the authorised distributor for Grindex submersible pumps and included in its product lineup is the well-respected Grindex Bravo range. Adams says these robust, durable and high performance pumps offers a good return on investment as the units are engineered to achieve lower operating and maintenance costs.

Commenting on why a submersible slurry pump is a better option for slurry pumping, Adams says that submersibles offer several benefits over dry-mounted pumps. They do not require any support structure, need less space for operation and are very easy to install.

The Grindex Bravo range are produced to operate over the complete pump curve, not just one specific duty point. This means that the pump can be used in numerous applications within its range and it is not a case of “one pump – one application”.

Grindex Bravo pumps are fitted with a cooling jacket and an agitator for effective slurry pumping. Pumps in the range can handle slurry and fluids with a high content of highly abrasive solids in sizes up to 50 mm at maximum heads from 17 to 45 metres. Wear is reduced by using NiHard 4 for all hydraulic components, and these pumps can handle liquids with pH values from 4 up to 10.

Adams also points to the high level of support that is available to customers across Africa through Integrated Pump Technology’s extensive distributor network which is underpinned by the company’s experienced technically competent African team. Ready access to parts also forms part of the support system, ensuring optimum uptime for customers.

LOCAL REMANUFACTURE OF GAS ENGINE COMPONENTS SAVES TIME, MONEY

As South Africa looks to make greater use of natural gas – and even landfill gas – in the generation of electricity, the good news is that the country has world class engine component remanufacturing capacity to optimise the lifespan and reliability of these generating sets.

At Metric Automotive Engineering in Germiston near Johannesburg, skilled staff and cutting edge facilities have been hard at work for decades, remanufacturing diesel and gas engine components to meet the exacting original equipment manufacturer (OEM) standards, says operations director Andrew Yorke.

“Making more use of gas as a power source is an exciting prospect for South Africa, both in terms of its reasonable cost and its lower environmental impact,” says Yorke. “However, equally positive is the fact that the expertise and state-of-the-art equipment to remanufacture these engine components is already here, and doing this work locally supports the economy, reduces turn-around times and cuts costs.”

He notes that while natural gas is generally a clean burning fuel, landfill creates a much harsher environment for an engine, as it is difficult to control the level of contaminants in gas that emanates from any particular landfill. This significantly reduces the intervals that the engine will require between maintenance interventions.

“The relatively poor quality of gas requires advanced ignition monitoring systems in the engine, but the wear rates remain high due to the highly abrasive post-combustion residue, despite filtering of the gas,” he says. “With natural gas, for example, cylinder heads will need to be replaced every 20,000 to 30,000 hours. With engines burning landfill gas, however, they could require attention as early as every 5,000 hours.”

Metric Automotive Engineering has already been conducting work for customers in the both the natural gas and landfill gas segments, where the generating capacity of the engines is usually between 1 MW and 10 MW. The company also provides customers with service exchange units, to enhance efficiency in the maintenance process and reduce downtime.

“Service exchange units allow customers to have remanufactured components like cylinder head assemblies readily available to take to site when worn components need replacement,” he says. “These engines are designed to have certain major components replaced in the field, so it makes no sense to be procuring these services from abroad where most of the original equipment comes from.”

Yorke highlighted the vital importance of high quality workmanship in conjunction with a disciplined and well-resourced maintenance schedule to optimise the performance and lifespan of these engines, while delivering lowest cost of ownership to the operator and reliable energy supply to the end- customer. Other items that the company remanufactures include valve-train components, connecting rods, crankshafts and cylinder blocks.

TRAFO’S CAST RESIN TRANSFORMERS READY FOR ACTION AT ZUIKERBOSCH

Dry-type transformer specialist Trafo Power Solutions secured the order for 13 custom-designed cast resin units for Rand Water’s large Zuikerbosch Wastewater Treatment Works near Vereeniging.

The water purification and sedimentation facilities at Zuikerbosch will reportedly provide an additional 600 Ml per day to the system at a project value of R3 billion, as part of efforts to meet growing water demand in Gauteng due to steady population migration into the province.

The transformers being provided by Trafo Power Solutions range in size from 100 kVA to 1,600 kVA and have been modified to include earth fault protection and surge protection. This is in addition to the standard temperature protection features.

“The key advantages of dry-type transformers in this kind of application is their inherent safety and their ease of installation,” says Trafo Power Solutions managing director David Claassen. “The units can be installed inside built substations rather than having to be placed outdoors with their own civils and bunding infrastructure.”

Unlike conventional oil-cooled transformers, the dry-type units do not carry the risk of oil leaks or spillage and hence do not require special mitigation measures to protect the environment. The technology’s relative safety also makes them more versatile in terms of the locations in which they may be housed. The units are self-extinguishing and flame-retardant by nature, allowing them to be categorised as ‘F1’ in terms of international fire ratings.

“The transformers represent state-of-the-art technology from the leaders in cast resin transformer products, Hammond Power Solutions (HPS) who has been developing this field for a century,” says Claassen. “We have sourced our custom-designed units from the group’s manufacturing facilities in Italy, which boast world-leading expertise and equipment.”

While dry-type transformers have been around since the early 1900s, they are becoming increasingly popular in a variety of applications as the price differential compared to conventional transformers is no longer significant.

Weir Minerals enhances pump maintenance with adjustment technology

With a longstanding reputation for engineering expertise, Weir Minerals continually develops solutions and technology to better serve the mining industry. Recognising that throatbush wear rate has a major impact in the overall efficiency of slurry pumps, Weir Minerals has developed superior rotating and axial adjustment technology.
In many applications, the pump’s throatbush is the component that has the shortest life compared to the impeller and liners, with considerable variability.
Adjusting the gap between the throatbush and the impeller front shroud reduces hydraulic recirculation in the pump. This prevents localised wear on the throatbush, improves hydraulic efficiency and lowers the total ownership cost for the operator. To avoid impacting the plant’s production, these adjustments are often performed while the pump is operating. However, this can have safety implications for individuals working at the front of the pump unit.
“Manually adjusting an alloy throatbush on a large pump requires several people and is labour intensive. It requires mechanical tools to adjust the four pusher bolts, one at a time, in order to reduce the gap between the throatbush and impeller. We wanted to find a safer and quicker way to extend the wear life of the pump with regular adjustments, which led us to development of this technology,” states Marcus Lane, Global Product Manager for Centrifugal Pumps for Weir Minerals.
“Our automated throatbush adjustment solutions are available for pumps fitted with either rubber or alloy throatbushes on Warman slurry pumps used in the most arduous applications, and have been designed with our customers’ safety and pump operation in mind. By mechanising the adjustment procedure, personnel are removed from the line of fire, and the accuracy of axial movement is increased,” states Ron Bourgeois, Director of Slurry Pumping Technology Group for Weir Minerals.
Weir Minerals’ automated adjustment systems speed up the process, allowing for more frequent adjustments with minimal effort. When maintaining an alloy throatbush, all four bolts are adjusted at the same time to ensure even adjustment and accurate positioning, improving the wear life of the throatbush.
Rubber throatbush adjustment is considerably different because it poses the risk of hysteresis and premature failure of the throatbush. The goal is not to adjust to a minimum clearance but to maintain a standard gap to ensure that there is no contact between the impeller and throatbush, whilst periodically rotating the throatbush face to avoid acceleration of localised wear.
“We developed an automated rotating solution which maintains an optimum gap between the throatbush and impeller front shroud for the particles to flow through without catching and tearing the rubber. The localised surface wear is usually near the discharge position, but by slowly rotating the throatbush, we even out the material loss over the entire face. Field results have been very positive, showing an average of 40% increase in wear life,” states Claudio Needham, Application Engineer for Weir Minerals.
For the smaller Warman® slurry pumps used in medium to heavy duty applications, Weir Minerals offers a single point adjustment mechanism, providing both axial and rotational repositioning. This allows one individual to safely stand to the side of the pump while making the adjustment.
Mining operators who have trialled Weir’s adjustment technology have reported improved wear life and safer, simpler maintenance through the process of regular adjustment.
Weir Minerals has already taken its adjustment technology one step further by integrating it with their IIoT Synertrex® platform to offer predictive maintenance feedback.
“This is made possible through machine learning. Over time Synertrex learns from past adjustments, recording how many times the throatbush was adjusted and the magnitude of adjustment each time. This trending data is collected and analysed by Synertrex to communicate future adjustment requirements. Through automating all adjustments, we can successfully communicate remaining useful life, and inform customers of optimum times to adjust the pump to increase efficiency and maximise wear life,” Marcus Lane concludes.