Tag Archives: Weba Chute Systems

WHY EPCMS GAIN FROM CONSIDERING TRANSFER POINTS EARLY

The mining sector relies increasingly on Engineering, Procurement and Construction Management (EPCM) firms for new builds and expansions – allowing miners to focus on their core mandates. 

The advantage of using EPCMs is their design and execution capability, which many mining companies have elected to reduce over the years. According to Weba Chute Systems project manager Ted Cruikshank, this usually streamlines the input of suppliers, allowing a focused and efficient relationship. 

“For EPCMs to get the best value from our decades of experience in transfer points, they really need to talk to us early in the project cycle – ideally at bankable feasibility stage,” says Cruikshank. “This can ensure that transfer points are optimally planned upfront, as the positioning of this infrastructure is vital to many other aspects of the plant.”

He notes that in the past five years or so, there has been a growing recognition that transfer points and chutes have a significant impact on the overall performance of process plants. They were previously considered as relatively small additions to plant layout, with more attention being paid to the larger items which carried a higher capital value. 

“What is now being appreciated is that poorly positioned or inadequately designed chutes can disrupt the entire plant process, costing mines dearly in terms of downtime, maintenance and repairs,” he says. “Mines pay the price of sub-standard equipment by having to deal with choking in the chutes, high wear-and-tear, spillage, skew belt loading, damaged idlers and other problems.”

These challenges can be avoided if EPCMs engage transfer point specialists early on, so that these experts help inform the plant layout before final design decisions need to be taken. By getting the right input in good time, EPCMs can also quote more accurately on their project costs. 

“For instance, if the positions and heights of key equipment in a plant have already been decided before we get involved, it means that designs must be altered in order to achieve optimal results,” says Cruikshank. “Alterations to existing plans invariably means added costs – which the end-customer is never happy about. By arriving at the right design first time around, the costing is more predictable and the reputation of the EPCM is enhanced.”

He notes that the height of a transfer point is an important variable in properly controlling the flow of ore through chutes and onto receiving conveyors with optimal belt loading, low impact and reduced wear. Before design stage, Weba Chute Systems gathers detailed technical information from the client on the mine’s material characteristics, lump sizes, tonnages, particle size distribution and other factors. Transfer chutes can then be custom-engineered to the right configuration, matched to the ore that needs to be moved. 

“We regularly see situations on mines where this process has not been followed, and where chutes are still regarded just as simple platework,” he says. “On one manganese mine in the Northern Cape, management called for our assistance when material flow across the operation became disrupted by dysfunctional chutes that would not last.”

The success of Weba Chute Systems’ intervention in this case led to them replacing almost 30 chutes on a single site, so that mine operations could resume normally. He also emphasises the maintenance-friendly design of the company’s chutes, for safer and quicker maintenance.

WEBA’S SWING DOOR STOPS CHUTE DAMAGE FROM LARGE ROCKS

Faced with a challenge of large rocks in the run-of-mine (ROM) feed regularly damaging main support structures, chutes and grizzly feeder a diamond mine in Botswana reached out to Weba Chute Systems to custom design an innovative solution to overcome this costly challenge, which included major safety hazards.

According to Hilton Buys, regional manager at Weba Chute Systems, the mine’s existing chutes at the ROM section were cracking and breaking under the barrage of heavy kimberlite rocks measuring up to a metre in diameter. 

“Even the robust grizzly feeder could not withstand the impact of these rocks, which were free-falling about two metres from an apron feeder before contact,” says Buys. “Apart from the costs incurred by this damage, the transfer points were posing a significant safety hazard to mine employees.”

The solution – designed and manufactured at Weba Chute Systems’ Wadeville facility – was a special four-tonne swing door in a discharge chute, feeding from the apron feeder to the grizzly. The heavy, fabricated door is strong enough to withstand the impact while absorbing the energy of the falling rocks before allowing them to drop onto the loading section of the grizzly. The feed can then move in a more controlled manner over the grizzly into the crusher below. 

“The key principle was for the door not to give way easily, thereby reducing the velocity and momentum of the large chunks,” he says.  

There was also a design requirement to accommodate the movement of smaller rocks. This was dealt with through the addition of a second door, to also ease these rocks onto the grizzly to ensure a more gradual feed into the crusher feed chute. The success of the design, which is based on the Weba Chute Systems principle of controlled flow, has been demonstrated in the chute’s ability to operate with very little maintenance, he says. The only components needing regular attention are chute lips and swing door rails. 

“We also included some specific design elements in the crusher feed chute, by installing impact rubbers,” says Buys. “Any rocks that may diverge from the main flow stream will then strike this rubber, minimising the vibration and impact on the body of the chute and are still able to drop gently into the crusher.”

Following on the success of this design, the solution was repeated at other customers’ sites, including mines in the Northern Cape which experienced similar challenges. 

WEBA STEPS IN TO SAVE MINE’S ENDLESS CHUTE WORRY

A primary crusher discharge chute had been a headache for a large Botswana diamond producer for many years. The crunch came when, after considerable capital expenditure, the new conventional chute needed maintenance just six weeks after installation.

“This could not continue and the mine needed a long term solution which is why we believe they came to us for a proposal,” says Hilton Buys, regional manager at Weba Chute Systems. “Senior experts from our company visited the site to take a careful look at the conditions the chute needed to deal with, and we took our conclusions back to our design office.”

Among the challenges were large lump sizes in the ore stream, contributing to build-up of material in the chute and regular choking, says Buys. Also, while Botswana’s dry season is long, the rain that does fall causes considerable problems to the flow dynamics. The kimberlite on the mine – depending on which part of the pit it comes from – can become very sticky in wet weather. 

“We therefore had to pay particular attention to flow angles, and the design had to effectively accommodate both wet and dry conditions,” he says. The concept design – which included quick-release lips on dead boxes – was approved by the mine and the final design, manufacture and successful installation was conducted.

Adding to the complexity was that the feed end of the primary crusher was some eight metres below ground level, while the crusher itself stood about 10 metres tall. The chute had to be positioned below the rock box which stores the material from the crusher discharge, channelling the stream into the Weba chute at a transfer height of nine metres to the conveyor belt. 

“The conventional chute also created excessive dust through uncontrolled rock velocity over this considerable transfer height,” he says. “By contrast, our chute’s controlled flow meant that the mine did not even have to apply its dust suppression system.”

After installation, Weba Chute Systems gave the customer a 12 month guarantee on this chute, as it does with all its new chutes. This, which comes with regular inspection reports, assures the customer that the performance will meet their expectations. 

“These inspections allow us to monitor wear, so we can advise the customer on what action is required so that they can schedule maintenance and avoid unexpected downtime,” Buys says. Installed in 2017, the chute is still operating with little maintenance, having been delivered at a highly competitive price compared to the one it replaced. 

“Designing a long lasting chute is not just about creating a box with some reinforcing where you think there will be wear,” he says. “It is an endeavour that must be scientific, based on in-depth analysis of material and flow conditions.”

Buys highlights the importance of asking a range of technical questions about the specific application so that the design answers those needs. The latest software and modelling tools are then applied by the Weba Chute Systems team to guide the most effective design. 

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. 

WHY DUST CONTROL IS VITAL TO MINERS’ HEALTH

Dust has long been a health hazard in mines where metals and metalloids are carried in atmospheric dust exposing workers to toxic contaminants.

In particular, the smaller particles of around 0,3 micron in size have the most serious impact on human health, says Izak Potgieter of Weba Chute Systems. Dust from minerals such as coal, silica and other finely powdered materials can damage the lungs and air passages.

“The Occupational Health and Safety (OSH) Act therefore specifies certain dust exposure limits, so that mines can measure and control dust, to ensure that levels are managed,” says Potgieter. “Health and safety officers monitor this on a regular basis as part of their compliance standards.”

He notes that dust is often generated during the transportation of minerals on conveyors and through transfer chutes. Measuring dust at these sources can be done using a handheld dust meter, typically gathering data in 30 second intervals with 0,003 split seconds per measurement. The data from this process can then be profiled into a scatter plot, considering factors like lump size, belt speed, relative humidity, wet-bulb temperature, wind conditions and material type.

“The lump size of the material being moved is usually a key factor affecting dust levels,” he says. “To understand the levels of dust being produced, data on the size and material type needs to be collected and analysed.”

The speed of conveyor belts will also affect the dust levels, Potgieter says, depending on the tonnage per hour traveling through the chute. Reducing the dangers of dust in this environment requires better flow control of the moving material, including velocity and impact on conveyors and in chutes. 

WEBA DEVELOPS TOOL TO MODEL RELIABILITY

Based on its experience in manufacturing and maintaining transfer points, Weba Chute Systems has developed a reliability model that allows customers to improve uptime in their plants.

According to Izak Potgieter, ISO systems manager at Weba Chute Systems, the tool is able to capture, store and calculate vital information about wear rates on different components within each chute. 

“The data specifies exactly which chute is being referenced, where it is physically located in the mine or plant, the components it includes and the dimensions of these components,” says Potgieter. “Data is captured over time on the tonnages that pass through the chute, and the wear that occurs on components such as lips, liners and dead boxes.”

When inspections of the chute are conducted, precise measurements are taken of wear levels so that comparisons can be made over time. The tool generates important calculations such as the wear rate per hour or per day, which allows forecasts to be made about key indicators such as mean time between failures (MTBF).

“By applying the concept of exponential distribution to the percentage reliability required by the customer, we can then calculate the number of hours that the chute should be able to operate between maintenance interventions,” he says. 

Average tonnages passing through the transfer point is usually gathered from the mine’s SCADA system. If these tonnages – or the nature of the material – does not change, then the wear life of each chute’s various components can be predicted fairly accurately. 

World-renowned Weba Chute Systems are used for bulk materials transfer in the industrial and mining sectors. As the leading manufacturer of bespoke chutes, the company engineers and produces quality transfer systems – each solution tailored to the specific application requirements aimed at enhancing productivity and reducing unscheduled downtime.

With more than 5000 chute systems operating worldwide, Weba Chute Systems has offices and representation in South Africa, Africa, Australasia, Russia, North America, South America and Europe. 

PROCESS EFFECTIVENESS UNDERPINS WEBA CHUTE QUALITY

Ensuring that every chute produced is to specification and to the highest quality, Weba Chute Systems gives customers peace-of-mind through its process effectiveness systems.

According to Izak Potgieter, ISO systems manager at Weba Chute Systems, process effectiveness assures customers that this leading transfer point manufacturer follows detailed protocols for each stage of the ordering, design and production process of its custom-engineered chute systems. 

“We apply a statistical process control (SPC) method right from the time that an order is placed, and this guides the process through to delivery,” says Potgieter. “This involves, for instance, careful verification and validation processes ensuring that all customer priorities and specifications are included in the design.”

This allows the design stage to use precise and accurate technical information such as exact belt speed, lump sizes and material characteristics – in turn resulting in reliable calculations for design and manufacturing purposes. Validation of the design is conducted, often using simulation methods, before it can advance to the drawing office for final, detailed design work. 

“A comprehensive file of information allows us to apply an SPC check on every aspect, so that the design addresses all requirements and can be taken further to the manufacturing stage,” he says. “Manufacturing and nesting drawings are completed, and manufacture proceeds in line with a quality control plan methodology with various holding, witnessing and verification points.”

Final assembly is signed off before the product is disassembled for transportation. Weba Chute Systems then also provides a technical assistance service, where a technical advisor will be placed on site to guide the installation team. 

“All of these process effectiveness stages are governed by our ISO certification, which has underpinned our quality performance for more than a decade,” says Potgieter. “Many of these processes are not even visible to the customer, but are critical in delivering the value we promise.”

ENGINEERING KNOW-HOW PUTS WEBA UP FRONT

In-house engineering capability as well as capacity is a cornerstone of the global success of leading chute designer and manufacturer Weba Chute Systems.

“What has always set us apart, especially in the local market, is that transfer points are our dedicated focus,” says Alwin Nienaber, technical director at Weba Chute Systems. “Underpinning this strength is our highly specialised and experienced design and engineering team, equipped with the latest tools to keep the company at the leading edge of technology.”

Nienaber highlights that it is this expertise that allows the company to custom engineer its solutions based on the specific and exacting requirements of each application. While the standard theoretical formulas and technical calculations can be easily sourced by anyone, he says, it is the practical experience and proprietary knowledge that adds real value.

“Over the past decades – during which we have supplied over 5000 chutes worldwide – we have built a wealth of practical experience,” he says. “We invest this in the design of every chute, so that customers benefit from the considerable ‘school fees’ that we have paid over time.”

By sharing performance feedback from the field, the company’s drawing office and design team works to continuously improve transfer point solutions. The engineering process also demands a close working relationship with each customer.

“Our success depends on accurate and reliable data from the customer – as they know their plant, process and material better than anyone,” he says. “This collaboration is indispensable for us, as we need this vital input to inform and guide our engineering parameters. The customer is very much part of reaching our engineering targets.”

The internal capability is enhanced by ongoing training and mentoring of staff, so that decades of learning can be passed on to new generations of specialists in the company. While designs are developed using the latest three-dimensional computer-aided design (CAD) software, the team also leverages discrete element modelling (DEM) as a verification tool to simulate and prove the functionality of the design.

The company makes extensive use of 3D scanning to achieve accurate measurements of the operating environment for each chute. This equipment is regularly updated, allowing for these scans to be performed in a fraction of the time possible just a few years ago, he says. Processing of the point cloud for CAD operability can also be performed much more efficiently by the latest technologies, making the designers’ work even more efficient.

“The depth and versatility of our expertise was recently demonstrated in a specialised chute application for a local platinum mining customer,” says Nienaber. “Working in conjunction with a hydraulics specialist, we provided a chute solution for an application where low-grade ore on a conveyor had to be rapidly diverted to a secondary stockpile. This test project involved two chutes, a high-pressure actuator and a high-speed trolley mechanism, to meet the mine’s material grade requirements.”

WEBA’S PRODUCT MEASUREMENTS PROVE PERFORMANCE

Mines expect to see performance improvement from their newly installed Weba Chute Systems, but this needs to be measured. Fortunately Weba Chute Systems provides a scientific approach to measuring this which leaves no doubt in the customer’s mind, and provides assurance that their newly installed Weba Chute System will reduce total cost of ownership. 

According to Izak Potgieter, ISO systems manager at Weba Chute Systems, the company conducts in-depth product measurements to make sure that its products are performing. In terms of dust management, for instance, this includes measuring dust levels of conventional chutes on the mine – even before the Weba product is installed.

“Our measuring procedures include a dust analysis programme that can compare a conventional chute with our custom-engineered product,” he says. “Our report to the customer sets out the details of our methodology, the results and the implications in terms of the Occupational Health and Safety (OSH) Act.”

Of particular importance is the exact quantity of smaller dust particles, in the size range below 0,3 microns, that are generated by material passing through the chute. Potgieter highlights that seeing the precise data from these scientific measuring techniques is an assurance to the customer of the value delivered by its chutes. 

The importance that Weba Chute Systems places on detailed measurement is also applied in the maintenance of transfer points. In this field, over a year of intense research and development was invested in calculation methods to reliably model the accuracy of maintenance for individual applications. “Our model tracks tonnages through the chute and the wear of vital components – among other factors – to calculate the wear life remaining,” he says. “This not only provides factual proof of the component lifespan that we predict to our customers, but also allows them to accurately plan their proactive maintenance – ensuring uptime and productivity.”

OUTLOOK STRONG AS WEBA SUPPLIES CHUTES THROUGH PANDEMIC

Momentum is picking up in demand levels from the commodities sector for companies like Weba Chute Systems, who has been able to quickly adapt to Covid-19 conditions.

According to Mark Baller, managing director of Weba Chute Systems, the past financial year certainly had its challenges, but performance was better than expected and, more importantly, the outlook for the future looks robust. The company has embraced remote working and digital communication technologies, ensuring that orders are fulfilled both locally and abroad.

“Among the exciting projects we have been able to pursue despite the pandemic is the supply of transfer chutes to a Turkish gold mine expansion,” says Baller. “We already have about 40 chutes in this plant, and have manufactured and delivered another batch recently – making up the bulk of chutes operating in this facility.”

Work in the southern African region has forged ahead, spurred on by an active manganese sector in South Africa’s Northern Cape province, where Weba Chute Systems has been integrally involved for the past two decades. At one mine expansion, the company has supplied over a dozen of its custom‑engineered chute systems.  

There have also been sales into Zimbabwe’s platinum sector, which shows considerable promise for further growth in the near future. While the diamond industry has not been having an easy time, Weba Chute Systems has continued its relationship with producers in Botswana, both in the maintenance of equipment and in the occasional supply of new units. Ongoing business continues to come from mining customers in the Democratic Republic of Congo and Namibia. The company also runs an operation in Australia, where most activity is focused on retrofitting and maintenance, he says.  

“Physically getting onto mine sites has been a challenge with the waves of Covid-19 infections leading to varying levels of travel and other restrictions,” he says. “Our network of local agents and technical partners around the world has been vital in helping us meet customer requirements through this difficult time.”

Baller highlights that these partners are chosen on the strength of their technical expertise and facilities, as well as their local market knowledge and understanding of customer requirements. To enhance their effectiveness in delivering quality service, Weba Chute Systems also provides intensive training to its agents on various aspects of its chute manufacture, installation and maintenance.