Tag Archives: transfer chutes

DRA Global’s ‘total solutions offering’ put to the test at Exxaro’s Grootegeluk mine

DRA Global says it has continued to sustain its long-term client relationship with Exxaro Resources through the progressive engineering, procurement and construction management (EPCM) contract at the Grootegeluk coal asset in South Africa.

Exxaro’s Grootegeluk is an open-pit coal mine, 20 km from Lephalale in Limpopo province. The mine produced 26 Mt/y final coal products, using a conventional truck and shovel operation, and has an estimated mineable coal reserve of 3,261 Mt, and a total measured coal resource of 4,719 Mt.

“A project of this magnitude speaks to the extensive experience in project development and delivery extended to the client by DRA,” DRA says.

DRA’s specialist engineering expertise and total solutions package at Exxaro’s Grootegeluk includes, but is not limited to:

  • Bankable feasibility study;
  • Installation of a new PC2 Discard Conveyor alongside the current PC1 Discard Conveyor;
  • Installation of new bifurcated transfer chutes to discharge onto either PC1 or PC2 Conveyor;
  • Seven transfers in total that requires conversion; and
  • Construction of associated infrastructure; such as stormwater control, road crossing, new spillage collection and a transfer system.

Furthermore, DRA recently completed the 3D scanning of existing conveyors and accompanying infrastructure. The compiling of the 3D model has commenced and will inform the engineering of the various transfer towers and the new PC2 Conveyor onto the next phase, it said.

Exxarro, in 2018, initially awarded DRA a contract to construct a 500 t/h coal handling and preparation plant at the Belfast Implementation project, in Mpumalanga.

“The client’s faith in DRA showcases the proficiency in implementing large-scale coal projects and further solidifies the organisations’ reputation for successful project delivery (even under these new circumstances),” it said.

Alistair Hodgkinson, Senior Vice President at DRA, said: “Grootegeluk is just one of many projects under DRA that provides an excellent opportunity to showcase our engineering capability. This is a complex brownfields project that will require attention to detail to achieve successful construction during a tight shutdown deadline; the client values our reputation for being able to deliver challenging brownfields projects successfully.”

The project commenced in the September quarter and is forecasted for completion by the June quarter of 2021.

Weba improves mining chute installation accuracy with 3D scanning

Transfer point specialist Weba Chute Systems & Solutions is leveraging three-dimensional (3D) scanning technology to ensure there are no surprises when designing and installing its products.

“The accuracy of 3D scanning means that we can rapidly gather detailed measurements of large infrastructure on a customer’s site,” Alwin Nienaber, the company’s Technical Director, says. “This data allows us to generate highly accurate 3D models of on-site conditions, which refines the accuracy of the equipment and componentry we develop and install in that environment.”

Greater accuracy keeps rework costs in design and manufacturing to a minimum and reduces any downtime during the installation phase, according to the company. Detailed 3D scan data allows all elements of the existing infrastructure to be considered during the preliminary design stage, so the customer is assured of a reliable costing in a project’s early feasibility stages.

Nienaber highlights that there may be numerous deformations or undocumented alterations in the customer’s existing infrastructure that could complicate the design and execution of a project. Manual measurement of dimensions may also not deliver the levels of accuracy required.

“Especially when we are replacing transfer points or chutes, we can significantly de-risk the process with our capacity to reverse-engineer the solution within the existing constraints,” he says. “The scanned data is superimposed on our design intent, alerting us to interference that will disrupt smooth installation.”

One of the key advantages of 3D scanning, therefore, is it contributes to the level of certainty that Weba Chute Systems & Solutions can achieve in the design and implementation of projects. The precision and portability of modern laser scanners have made them invaluable in designing, building and extending technical facilities, the company says.

“Our decades of experience in the mining environment give us the capacity to fully leverage the value of 3D scanning to the benefit of our customers,” Nienaber says. “This means accurate costing and seamless project roll-out – on time and on budget.”

This is increasingly important as mines drive for productivity gains and prioritise uptime, with many retrofit or maintenance projects required to be conducted during the strict shutdown periods on mines.

“Our engineering know-how is central to integrating 3D scanning into our design and manufacturing processes, improving our planning and scheduling through more precise data,” Nienaber says. “We translate this capacity into reduced project risk and lower contingency costs – allowing us to work efficiently at a low margin of error even under the time constraints in these projects.”

Weba’s custom-designed chutes find favour in Africa

Weba Chute Systems’ Wade Vandenberg says mines across Africa are recognising the value of the company’s custom-designed chutes in controlling material flow, extending wear life and reducing maintenance downtime.

The South Africa-based company’s transfer point solutions have made their way into mines across Africa, from platinum to diamond operations, to gold, coal and copper mines.

In addition to mining hotspots including Ghana, Mali, the Democratic Republic of the Congo, Zambia, Zimbabwe and Botswana, Weba Chute Systems have been installed in countries like Tanzania, Mauritania and Eritrea, it says. Authorised Weba Chute Systems agents are deployed to support customers in key countries, while technical experts from the company’s head office in Germiston, Gauteng, South Africa, are on call to assist.

Vandenberg, Weba Chute Systems’ Technical Advisor, Africa, said: “Not only do these operations gain the benefits of controlled material flow in their operations, but they experience, first-hand, how our engineering design extends wear life and reduces maintenance downtime.”

He highlighted that better dust control – a key part of health and safety policies in the mining sector – is another important benefit Weba chutes bring to an operation.

“Our state-of-the-art digital engineering design facilities and expertise makes use of the latest technologies to simulate the specific material flow conditions in each customer’s application,” Vandenberg said. “This allows us to apply our philosophy that no two chute designs are identical, and to scientifically accommodate exact flow characteristics into our design.”

Discrete element modelling allows close control over the flow of material through the chute. This minimises turbulence, reducing the levels of dust created in the working area. It also cuts spillage levels, which, in turn, means a saving of valuable material and less time spent on cleaning activities.

Izak Potgieter, Systems Manager at Weba Chute Systems, said: “We work towards the ISO dust management standards, supporting our customers in managing health and safety in this critical area of transfer points. Our testing measures dust down to 0.03 micron particles, to make sure that our designs meet stringent health-related targets.”

Flow control also creates more material-on-material movement to reduce wear on chute liners, according to Weba. This ensures longer liner life when compared with that of conventional chutes. Custom design and use of simulation technology allow for the wear life to be carefully predicted, based on operating conditions, the company says.

Vandenberg said: “Our technical expertise and solutions-oriented approach mean that customers can always rely on us. When we commission one of our chutes, it is part of an ongoing productivity journey with our customer, no matter where they are located.”

Weba Chute Systems called in for Mexico gold tailings project

As part of a significant investment to improve its processing facilities and enable the recovery of 40% of the gold that currently sits in its tailings as waste, a mining operation in Mexico called in a leading transfer point and chute systems equipment manufacturer to conduct a thorough assessment on the functionality of existing chutes in the plant.

Weba Chute Systems & Solutions, leveraging its knowledge of material behaviour in chute systems, was tasked with establishing the feasibility of introducing filtered tailings at a rate of 1,200 t/h onto the existing transfer system currently handling waste with a nominal size of 400 mm at a rate of 5,000 t/h.

While the intention is for the filtered tailings to be conveyed when the waste rock is available, it would still mean the same chutes would need to function transferring completely different material, according to Alwin Nienaber, Technical Director of Weba Chute Systems.

“Optimally, one should be able to assess a working transfer chute handling the actual material, however in the case of a feasibility assessment this is not possible, and we therefore started with a review of the test work and studies prepared by independent qualified professional materials handling experts.”

This was done by Weba Chute Systems & Solutions calibrating the material conditions and behaviour using discrete element method (DEM). Nienaber said: “Use of DEM allowed our technical team to model the interaction between individual particles and boundaries and, in so doing, to accurately predict the bulk solids behaviour.”

Access to DEM software allows engineers to predict bulk material flow patterns and flow rates as well as velocity patterns and dead zones within a transfer system, according to Weba. It also provides accurate information on particle distribution in segregation and blending and the impact forces on particles and boundary surfaces, showing wear patterns.

The feasibility assessment included the transfer of sedimentary dry tailings, sedimentary filter cake, breccia dry tailings and breccia filter cake. DEM modelling was carried out considering material on its own and conditions where blended material would be conveyed.

In total, there were four conveyor transfer points that had to be assessed. These included an inline transfer point, a 90° transfer point, a transfer from conveyor to radial spreader intermediate conveyor and then onto the spreader boom conveyor.