In the mining environment, chutes are generally designed to manage some variance in the loads being transported by conveyor systems – but drastic changes in conveyor belt speeds can introduce complications.

According to Dewald Tintinger, Technical Manager at Chute Systems, chutes are designed with the width of the conveyor belt in mind – accommodating the various levels of loading on these belts. Changing the speed of the belt significantly, however, can affect not only the volume of material entering the chute, but the first point of contact in the chute as the material leaves the belt.

“The speed of the conveyor belt has a direct impact on the trajectory of material when it reaches the chute,” says Tintinger. “When changing the belt speed from 2,5 m/s to 3 m/s, for example, the chute would easily accommodate this. However, if the speed was doubled, this would change the trajectory so that the material impacts a different point in the conveyor, and at a different angle.”

He explains that Weba Chute Systems adopts a customised approach to each chute’s specific application, modelling the flow of material to guide the final design. Among the calculations is the initial velocity of the material leaving the conveyor belt, and the precise impact point on the inside wall of the chute.

Using the dead box principle to optimise material-on-material flow, the position of the first dead box in the chute will match this impact point. A higher speed of material will start to straighten the trajectory and change the impact angle.

“As the impact angle approaches 90 degrees, there is a risk that material flow could stall,” he says. “Rather than slowing down on impact and then accelerating downward towards the discharge point, the material could start backing up and clog the chute.”

While some chute manufacturers introduce platework to bend the trajectory of material, this adds to the wear on the chute. Weba Chute Systems generally applies its full cascade designs, using dead box sections to reduce the impact and speed.

“The change of angle of material onto the first dead-box will not necessarily change the flow pattern, but it is likely to affect the speed of material through the chute,” says Tintinger. “It is therefore important to check the chute’s capacity to still allow enough material to pass through smoothly.”

General maintenance service providers often overlook the intricate engineering design of specialised on-mine equipment, leading to significant long term costs for mining operations. This issue extends to transfer chutes and other mining infrastructure, Farouk Abrahams, Sales Director at Weba Chute Systems, notes. He explains that poor maintenance typically results in unscheduled stoppages due to equipment failure,  compromising mining operations.

Abrahams points out that mines often outsource maintenance to general service providers in an effort to cut costs. Ironically, this approach often results in the opposite effect, with production revenue suffering due to these misguided cost-saving measures. He emphasises that inadequate maintenance undermines the value that original equipment manufacturers (OEMs) promise.

“For Weba Chute Systems, our chutes are custom-engineered for specific duties; any shortcuts in maintenance, such as using inferior materials, can significantly reduce performance and lifespan. This can lead to costly operational consequences including increased impact on conveyor belts, resulting in damage, spillage at transfer points and higher dust emissions—all requiring immediate attention,” he says.

The value brought by OEMs extends beyond just the physical products they supply. OEMs bring a wealth of specialised experience to each product, adding considerable value to a mine’s overall efficiency, safety and profitability. Their deep understanding of the equipment’s design and operational demands ensures maintenance performed will uphold the equipment’s performance standards.

“This expertise translates into smoother mining operations, as our team’s extensive practice in the field allows them to guarantee the outcome of every intervention. The reliability offered by OEMs such as Weba Chute Systems, extends to the timely sourcing or delivery of spares and the convenient scheduling of necessary maintenance.”

Abrahams shares that poor maintenance can drastically reduce plant availability. For instance, by collaborating with a customer on maintenance, Weba Chute Systems was able to maintain plant availability as high as 98%. However, when the mine switched to a general contractor to save costs, availability plummeted to below 90%. Such a decline in performance can be catastrophic for a mine, with minimal operating expenditure savings far outweighed by revenue losses.

Moreover, the impact of inadequate maintenance on specialised equipment like transfer chutes can extend beyond immediate operational issues. The cascading effects of reduced equipment efficiency can strain other parts of the mining operation. “For example,” Abrahams says, “compromised chutes can lead to irregular material flow affecting downstream processes and equipment, increasing wear and tear and necessitating more frequent repairs and replacements. This not only disrupts production schedules but also inflates maintenance budgets.”

“When we maintain our own equipment, we uphold the high standards to which the equipment is designed and manufactured. This commitment ensures reliability and has earned our customers’ trust, demonstrating the true value of specialised maintenance over general service providers,” he says. By ensuring that every component and material used meets the stringent requirements of the original design, OEM maintenance preserves the integrity and efficiency of the equipment, safeguarding the mine’s operational continuity and profitability.

In addition, partnering with OEMs for maintenance can provide mines with access to the latest technological advancements and updates. OEMs are continually improving their designs and incorporating new technologies to enhance performance and efficiency. By engaging with the OEM for maintenance, mines can benefit from these innovations, ensuring their equipment will perform reliably.

With the promise that its customised transfer point solutions will always perform to expectations, Weba Chute Systems tackles its turnkey projects in a highly systematic and controlled manner.

The company has successfully carried out more than 25 turnkey projects in the past decade, according to Weba Chute Systems project manager Ted Cruickshank, including contracts in the mining, steel, ports and food industries. Among these substantial projects was the design, manufacture and installation of 36 chutes at a steel maker’s sinter plant in South Africa, and 11 chutes for a project house developing a mine in Zambia.

“More recently, we completed a turnkey project for a number of crusher chutes at a platinum mine in Zimbabwe,” Cruickshank says. Further afield, Weba Chute Systems has provided chute designs to accommodate a three-way conveyor in an operation in Trinidad and Tobago in the Caribbean, now awaiting execution.

Attention to detail

“It all starts with defining the project’s objectives and scope,” explains Cruickshank. “This is followed by establishing the budget so that an accurate quotation can be prepared, as well as planning a timeline that meets the customer’s schedule.”

Turnkey projects demand clear channels of communication, he emphasises, so a regular meeting schedule is agreed with the customer to ensure that all stakeholders are kept informed throughout the project cycle. This is particularly important for dealing timeously with issues so that the project’s progress is not unduly impeded.

“On some projects, we can work off the customer’s drawings, but we often go to site to conduct our own surveys, on which we base our calculations and designs,” explains Cruickshank. Chute flow designs and layouts are then completed and approved, followed by fabrication approvals – all within a stringent Quality Control Plan (QCP).

Eyes on quality

“Our efficient procurement allows fabrication to get underway without delay, and stringent quality checks are carried out at every stage of manufacture,” he says.

Cruickshank emphasises that rework needs to be avoided if projects are to run on-time and on-budget, and this means stringent quality control. Weba Chute Systems uses ISO 9001-2015 as the standard to document and control all quality related activities.

“Regular audits and certifications help maintain a high level of consistency in the quality of our products across all projects,” he says. “Quality inspections at different project locations ensures that the equipment adheres to the project’s quality standards.”

Mitigating risk

A risk assessment on each project identifies all potential hazards and is the basis for mitigation plans to reduce risk. There is also growing pressure on mines and their contractors to minimise environmental impacts.

“Noise, dust and spillage are among the main environmental risks associated with transfer chutes,” he notes. “We mitigate these impacts through optimising the flow dynamics in our tailored chute designs – accommodating the specific conditions of each application.”

This includes understanding the material’s characteristics and particle size distribution, as well as its flow rate, trajectory, velocity and points of impact. Optimised material flow decreases the turbulence at the transfer point, in turn reducing dust and noise. Smooth transfer of material to and from conveyor belts also cuts the spillage and improves health and safety conditions around the belts.

Leveraging technology

He highlights the value of project planning software to plan and monitor progress during turnkey projects. These tools enhance real-time collaboration and efficiency, with other enabling technologies including three-dimensional modelling and data management.

“We also use video conferencing and cloud-based document handling to streamline our communication with customers and other parties to the project,” he says. “This improves overall efficiency and resource coordination.”

Cruickshank concludes by highlighting the value of local suppliers, engineers and partners in the country where the turnkey project is being executed. Weba Chute Systems prioritises these links by building positive long term relationships with local partners to overcome potential barriers of culture, language, lead times and cost efficiency.

Custom engineered chutes are scientifically designed and simulated prior to manufacturing by Weba Chute Systems to give customers optimal uptime – but the company has also innovated ways to keep these transfer points well maintained.

Channeling the flow of mined material is among the most onerous tasks on any mine, and Weba Chute Systems designs and manufactures its solutions to withstand these demanding applications. The considerable wear on the components in a transfer point, however, requires constant monitoring and attention. The company has therefore developed a range of responses to help customers to manage this important responsibility.

According to Izak Potgieter, ISO Systems Manager at Weba Chute Systems, a vital role is played by the company’s technical advisors, who visit customers on a regular basis to check the operation and condition of the chutes.

“To make their work efficient, and to quickly provide the customer with relevant information, we developed our own chute inspection app for our technicians,” says Potgieter. “This allows them to capture the necessary data and photographs from their inspection, to generate an automated report to guide the customer in their decisions.”

The company also has a reliability model which tracks the duty and condition of each chute over time, and which can inform a predictive maintenance programme. Through its decades of experience, the company has developed a detailed understanding of chutes’ wear trends under varying material conditions.

“Using these models, we can help customers to predict – weeks, months and even years in advance – which aspects of the chute will need maintenance,” he says. “This allows the necessary planning to be done, so that unexpected failures do not occur.”

He notes that Weba Chute Systems’ ISO 9001 accredited quality processes ensure that the spare parts manufactured at its advanced Wadeville facility are consistently what customers require. Collaborating with customers on their maintenance needs therefore also ensures that the right parts are available when required.

Faizel Mahomed, Client Services Manager at Weba Chute Systems, explains that mining conditions at customers’ operations can be expected to change over time. More abrasive ore, for example, or larger lump sizes, may result in faster wear on certain components.

“This makes our close contact with customers even more vital, as we can work with them to adapt to changing conditions,” says Mahomed. “Sometimes increased wear is unavoidable, and we develop innovations that meet these demands – such as our collaboration with a foundry partner to develop liners with 600 Brunel hardness for longer life.”

Among the faster wearing items on a chute is the lip, and to save time Weba Chute Systems has developed a quick-release lip for ease of replacement. He also points to the company’s innovation of a liner that can be replaced from the outside of the chute. This makes it safer and more efficient for the technician, who does not need to enter the chute. Chutes are often mission-critical for a mine, emphasises Potgieter, and in these cases the customer can take advantage of Weba Chute Systems’ maintenance contracts. These arrangements put a dedicated team on site to monitor and report on equipment condition, and to coordinate the necessary maintenance with the mine’s responsible officials.

Transfer chute wear life measurement, an intricate process involving meticulous tracking of multiple components, is essential for enhancing uptime in materials handling applications — a direct contributor to operational efficiency. Izak Potgieter, Quality Systems Engineer at Weba Chute Systems, says that in its relentless pursuit of innovative solutions, the company pioneered a state-of-the-art reliability model which has over time gained momentum with many plants relying on this to predict maintenance requirements. The model embodies a specialised approach to the intricate task of chute wear monitoring.

“Our custom reliability model is adeptly engineered to encapsulate pivotal wear indicators for each chute,” Potgieter explains. “This level of precision enables us to accurately predict the wear life of individual components, from liners to lips and beyond.”

For the model to function optimally, the integration of specific data is imperative—especially wear measurements obtained during regular inspections. Potgieter says that the discernment of wear patterns is of paramount significance, and that when furnished with this intel, plant operators are in a position to judiciously forecast which components necessitate imminent substitution.”

This capability is indispensable, and facilitates accurate and methodical planning, such as the timely procurement of pivotal components. It also strengthens preventive maintenance measures. The consequent elimination of unanticipated downtime safeguards a plant against disruptions and the ensuing loss of precious production hours.

“The capability to precisely predict component wear life has catapulted our maintenance paradigm to unparalleled heights, and this approach has received increased interest from customers, both those with Weba chute installations and other customer who are looking to changeover to more cost efficient transfer points,” he says. “While this tool is integral to our maintenance contracts, it merits mention that customers who do not have such agreements can still make use of this service from us.”

An auxiliary benefit of the reliability model is a comprehensive monthly dossier, providing stakeholders with timely alerts regarding maintenance requirements for each wear part within all chutes. The sophistication of this model is evidenced in its capacity to mirror differential wear levels across varied chute sections—especially those experiencing disparate impact levels. This granularity facilitates a targeted maintenance strategy, bolstering performance and longevity.

In the world of mining and industrial material handling, transfer chutes play a crucial role in maintaining smooth and efficient operations. While many manufacturers offer similar products, it is the uncompromising standards of Weba Chute Systems that sets this South African-based OEM apart. 

With a dedicated focus on design, engineering and manufacturing, Weba Chute Systems has elevated the science of transfer chutes, providing customers, both in Africa and overseas, with unparalleled peace-of-mind and reliable solutions.

Contrary to common misconceptions, transfer chutes are not mere platework commodities that any general fabricator can produce on demand. Dewald Tintinger, Technical Manager at Weba Chute Systems, stresses the danger of adopting such an approach. “Generic chutes often result in suboptimal performance, unreliable operation and a lack of technical support when it is most needed,” he cautions.

“At Weba Chute Systems, every transfer point solution is custom-engineered to address specific material and operating conditions on-site. We leverage our extensive design capabilities and field experience in the process and our skilled draughtsmen employ the latest specialised software to model material flow accurately,” he says. “This meticulous approach ensures the optimisation of material trajectory, minimising impacts and disruptions during transfer.”

Further to this, he affirms that Weba Chute Systems takes pride in standing behind every chute produced. The company offers technical backup and support, ensuring that Weba chutes deliver consistent and reliable performance. “Our specially-trained technicians undertake regular inspections ensuring that proactive maintenance can be done, and where necessary customers can be forewarned regarding any issues. This approach enables informed decisions to be made and eliminates costly downtime due to premature chute failure.” 

Tintinger emphasises the importance of involving transfer point specialists in the early stages of plant planning and design. “Our team’s experience and detailed knowledge of how transfer points and chutes work allow them to offer valuable guidance on positioning equipment for optimal material flow. By strategically placing chutes and other equipment, plants can significantly improve efficiency, resulting in enhanced production outcomes and cost savings.” 

“While transfer chutes may be perceived to be relatively low-cost items within the overall process equipment flowsheet, these can become sources of significant and expensive operational problems when not properly engineered or maintained,” he continues. “We offer a solution to this issue by ensuring that our chutes are designed and installed to minimise disruptions and prevent costly downtime.” 

“We believe that by prioritising reliability, technical support and early engagement in the planning stages, Weba Chute Systems empowers its customers with the tools they need to achieve smooth and efficient material transfer operations,” Tintinger concludes. 

Handling sticky material in mining and minerals processing plants can be a complex challenge. These materials can cause blockages, equipment wear and increased maintenance requirements, leading to reduced efficiency and increased operational costs.

This is according to Alwin Nienaber, Technical Director at Weba Chute Systems, who says that designing transfer points to effectively handle sticky materials is crucial for optimising material flow and minimizing downtime. “There are a number of key design considerations for transfer points and it is for this reason that EPCM contractors and end-users should work closely with specialist companies such as ourselves who have the requisite expertise and legacy knowledge to deal with complicated materials transfer.”

An important consideration is material flow control, which Nienaber explains is crucial to avoid blockages and build-up of sticky materials within chute systems.

“This is where chute geometry plays a significant role in handling sticky materials, with experience informing the design of a chute to minimise impact forces and reduce material degradation. Minimising is also important, and this can be achieved through the use of wear-resistant materials such as ceramic tiles or rubber linings, and further extend the service life of transfer points while reducing maintenance requirements,” he says.

Nienaber says it is also important to control moisture levels when handling sticky materials. Excessive moisture can exacerbate the stickiness of materials, leading to increased build-up and blockages. Implementing moisture control strategies, such as proper drainage systems, dust suppression or material conditioning systems, can help maintain optimal moisture levels and improve material flow.

Material segregation and excessive particle size can also contribute to sticky material challenges at transfer points. This, he says, is where implementing strategies to minimise material segregation, such as proper stockpile management and the use of blending systems, can help maintain consistent material properties.

“Additionally, reducing particle size through controlled crushing or screening can help improve material flow and reduce the stickiness of the material,” Nienaber adds.

Viewing transfer points holistically should also include attention to other aspects in materials handling such as belt cleaning systems which are vital for preventing carryback and will also reduce material build-up at transfer points. Installing primary and secondary belt cleaners, along with belt tracking systems, can ensure that belts are free from sticky material carryback. This not only reduces the chances of blockages but also minimises belt wear and extends belt life.

“Implementing well-thought out design strategies from an experience transfer point OEM can certainly assist mining and minerals processing operations to optimise material flow, reduce equipment wear and maintenance requirements, and ultimately improve overall efficiency and productivity,” Nienaber concludes.

The generation of coal dust around conveyer systems and transfer points is a problem for operators of coal mines, coal plants and similar facilities. Coal dust is a contributor to lung disease and it therefore poses a threat to not only workers in these facilities but even to residents of neighbouring communities. It also poses a safety hazard, as it can spontaneously ignite causing potentially life-threatening fires.

Coal dust also impacts on the efficiency of coal handling systems – and hence productivity and profits. Equipment and machinery can become thickly coated with dust, which increases the need for regular cleaning, while dust ingress into moving machinery reduces its lifespan.

To control the problem, reliance is generally placed on dust suppression and dust extraction systems. While this all well and good, there is a tendency to over-rely on these systems, which results in them doing more ‘heavy lifting’ than they need to and often more than they can manage.

According to Alwin Nienaber, Technical Director of South Africa’s Weba Chute Systems, a globally recognised leader in chute technology, a more effective approach is to focus on the engineering and positioning of the transfer chutes that form an integral part of most conveyor systems.

“This can relieve 50 to 80 % of the problem,” he says. “Suppression and extraction of the remaining dust then becomes a much more efficient component in a broader and more holistic solution.”

He adds that at the heart of any effort to control dust is an understanding of material flow and of the effects of uncontrolled velocity and impact. As he says, “Dust is really just one of a number of unwanted consequences of a lack of control over material flow, including degradation of the material being moved.”

Reinforcing this point, Nienaber’s colleague, Dewald Tintinger, Technical Manager at Weba Chute Systems, notes that most chutes simply provide an open channel for material to fall through, before being discharged onto the next conveyor or outlet. The result is that material can spread in an uncontrolled manner as it travels, which invariably creates much more dust than is necessary.

Tintinger says Weba Chute Systems can provide custom-engineered chute designs which deliberately create a flow path for the material based on its inherent qualities, speed and volume and the throughput requirements of the installation.

“Using sound engineering principles, chutes can be designed to minimise the physical impacts that create dust,” he says. “We base designs on the ‘supertube’ effect, allowing controlled transfer of material onto the conveyor belt. This also reduces wear and tear on the belt.”

To allow it to model the behaviour of material being transported via conveyors and chutes, Weba deploys specialised technology including three-dimensional software. It also verifies its designs prior to manufacture using discrete element method (DEM) simulation.

As a final point, Nienaber says that strategies to control coal dust are best formulated at the design stage and that the earlier Weba Chute Systems is involved, the better the outcome.

“The configuration or general arrangement of equipment within a plant or between structures is important,” he maintains. “In our experience, we have seen the benefit of being able to advise plant designers on the optimal positioning of chutes and related equipment at the planning stage. The result is invariably a sharp reduction in dust creation and a more efficient flow of material.”