New coal and ore handling technologies designed to overcome production-limiting factors at mines and bulk handling terminals throughout Australia are proving their worth in service.
The technology packages by locally and internationally experienced coal and minerals handling specialists, Chute Technology, are designed to eliminate potential bottlenecks, OH&S issues and weak links in the production chain that can increase downtime and reduce output.
Typical issues include bin surging, bulk cleaning, spillages, blockages and reduced throughput rates, resulting in inefficient production. One far-sighted operation that saw the potential in new technologies was the 24/7 Ulan Surface Operations in the western coalfields of NSW, which employs more than 900 people across its open cut and underground mines.
“Chute Technology designed a customised chute that is eliminating potential downtime for this section of the bypass system,” said Mr Dennis Pomfret, Managing Director, Chute Technology.
The new chute has dramatically reduced downtime since commissioning. By contrast the legacy arrangements were a source of multiple hours of lost production.
“The new chute allows Ulan Surface Operations to operate with a full feed rate of 2,000 tonnes per hour without any stoppages or blockages, so they can maximise their productivity and our profitability,” said Mr Pomfret.
Spillage, as shown in the example above, is a common problem that plagues mine sites across Australia and internationally.Ulan Surface Operations’ new chute has totally eliminated any spillage, which has helped productivity and uptime.
Chute Technology combines its decades of Australian and international practical engineering experience with advanced expertise in new flow enhancement and problem-solving technologies to produce modern answers to minerals and materials handling problems. The company provides audits and solutions extending from single issues at individual plants through to whole-of-process improvements extending from mines to port or point of resource use.
Mr Pomfret said that Ulan Surface Operations was looking to the future by investing in a solution designed to maximise productivity and eliminate unwanted downtime.
“We’re delighted that we could make Ulan Surface Operations’ bypass vision come to life, and it’s rewarding to see it working out in service. Ulan Surface Operations is always looking to employ modern solutions that avoid problems in the first place, rather than cleaning up a mess after it occurs,” he said.
Chute Technology performed an audit of current operations to gain a holistic view of current operations, before recommending the ideal solution. The engineering audit determined that functionality of one known trouble spot, the bypass hopper and vibratory feeder, could be taken out of service and replaced with a simpler transfer chute with an in-built surge capacity.
The Chute Technology problem solving process. From left to right, the previous set-up at Ulan Surface Operations, a DEM model of the new chute, the designed model, ready for fabrication, and the newly installed chute. The chute was designed in such a way that it could all be lifted and installed in one go, minimising installation downtime.
Chute Technology also designed and installed an adjustable surge control baffle device to control the height of material on the conveyor belt. The device acts like a trimmer on the end of the chute, where it trims the height of material during times of surge loading, to avoid belt overloading, side spillage and keep material heights consistent.
“We anticipate the surge control device will reduce spillage considerably, especially when taking into account the typical delays in conveyor stopping and starting sequences,” said Mr Pomfret.
“A major consideration for the project was to design the new chute around the existing structures as much as possible, so that there was as little rework or modifications needed before installation,” he said.
“We also took into consideration that the drop height is almost 15 metres. Ulan Surface Operations wished to retain their surge bin, floor structure, vibrating feeder and conveyor structures, so we designed around these as much as was possible. Additionally, the design was modular, so the installation took as little time as possible.”
Safety and performance audits
As part of the upgrade, Chute Technology performed a series of audits and tests to ensure safety and productivity of the system and its component parts once the new chute was in place. These tests included:
The new chute was tested to extreme weather conditions, from -10oC to +50oC, particularly testing the expansion and contraction of the steel components under different temperature extremes.
Load testing of the dump hopper bin, to ensure it had the required residual strength to support the weight of the new platform installed around the head pulley.
Engineering checks to ensure the conveyor belt is able to restart without overheating the fluid couplings, even when the chute is full. Idler frames were added to reduce belt sag.
A conveyor system audit, which included three conveyors located prior to the bypass chute. To effectively control surge volumes, Chute Technology installed two surge control baffles – one on the bypass chute and one on the chute prior to the bypass. The end result was that it minimised the potential for spillage, belt overload and downtime in chute restarts after a crash, emergency or controlled stop.
To overcome a variety of materials handling and chute challenges in this complex and unique project, Chute Technology used optimised technology, such as:
Asymmetric chute. Most side loading chutes cause belt mis-tracking issues because the sideways travel of the material exerts sideways forces at the loading point of the belt. Chute Technology’s DEM technology and expertise meant they were able to guarantee correct conveyor loading by cancelling out the sideway forces by optimising the internal flow geometry before the load point.
Virtual skirtboard. Again, by optimising the internal flow geometry the material is laid on the belt without contact with the conventional skirtboards, which creates a virtual skirtboard that is free of wear and spillage. Conventional designs are prone to spillage and can cause belt wear, but this has been totally eliminated at Ulan Surface Operations.
Single point of contact flow path. To further control wear rates, dust, and noise generation, Chute Technology designed the chute so that the material flow is constantly in contact with the chute from the head pulley to the receiving belt, thereby eliminating damaging intermediate free-fall trajectories and impact zones that are common with conventional smooth flow chutes. Potential transfer chute issues such as high wear, high surface temperatures, tile cracking, dust generation and noise generation have been avoided through unique design practices and fewer impact points.
With such a strong return on investment (ROI) and the chute already operating as designed, with no downtime, the project is already being seen as a template for the future.
“This project has been an excellent success, and we look forward to a long-term relationship with Ulan Surface Operations, as they look to maximise productivity and profitability,” said Mr Pomfret.