When geological challenges threatened coal supply to the Mount Piper Power Station, Mobile Conveyor Services was called upon to deliver a unique solution.
Geological challenges at Centennial Coal Company Limited’s Springvale mine led to quantity and quality concerns for Energy Australia and the Mount Piper Power Station (MPPS).
MPPS is situated near Lithgow, NSW, and generates 1400 megawatts of power annually.
In response, MPPS needed to conserve coal, effectively reducing output. One alternate source of coal was Centennial’s Airly mine at Capertee, 30 kilometres north of MPPS.
However, Centennial’s Lidsdale Siding at Wallerawang was not designed for receiving coal – the siding was used for loading coal for export.
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With its history of solving difficult bulk handling problems using innovative conveyor-based solutions, Mobile Conveyor Services (MCS) was called upon to help design, build and install a train unloader and connection to the existing overland conveyor feeding MPPS.
Russell Hart, Centennial’s Group Manager Projects, says Mobile Conveying Services were involved from the outset, working quickly to conceptualise a mobile rail unloading solution to meet this challenge.
“When coal production challenges presented themselves at Springvale Colliery in early 2019, Centennial set about developing an opportunity to rail in coal from their Airly Mine in support of Energy Australia’s Mount Piper power station,” Hart says.
“Once the solution was agreed and approved, Mobile Conveying Services then rapidly procured, mobilised, constructed and commissioned the mobile system in an incredibly compressed schedule.”
Making the most of a compressed space
With MPPS looking to be back in full operation by the time of the peak summer demand, the pressure was on to find a solution that was not only functional but also quick to implement.
The most viable location for a train unloader was in the coal spillage sump beneath the existing train loading bin. Under normal operation, this spillage sump would collect overflow from the loading process and would be cleaned out by skid-steer loader, accessed by a short, inclined ramp.
As the pit was significantly smaller than any off-the-shelf train unloader, it required a solution purpose-built for the dimensions of the pit.
To quickly gauge the size of structure that could be used in the pit, MCS technicians used angle iron and clamps to assemble a mock-up conveyor frame inside the pit and then used that mock-up as a guide for the final structure.
Two feeder conveyors were fitted side-by-side in the pit, with deflector plates fitted to direct material onto the belts. Access for maintenance and repair is less than ideal but was the best that could be achieved within the constraints of the area available.
The coal discharged from the train is conveyed up the ramp and directed via transfer conveyors and an overland conveyor to a telescopic radial stacking conveyor (1200 millimetres wide belt, 46 metre reach) that builds a stockpile over an MCS-built stockpile reclaimer that was the only major piece of equipment fabricated in the MCS factory.
Six modified containers were used to form side walls to guide stockpiled coal into the openings to the belt. The use of containers reduced the need for fabrication, helping to achieve the tight construction schedule.
Conveyors from the reclaimer then linked with the main power station feed overland conveyor, via another 60-metre reach radial stacker.
Commissioning
A team of MCS people led by Operations Manager Steve Valpreda worked in conditions that were often challenging to assemble and test the conveyor system. Mobilisation to site commenced on 12 September 2019. A trial train ran over the unloader on 22 October, with minor modifications made and implemented in time for a second train unloading on 28 October.
These modifications included shadow bars on the impact bed and upgraded conveyor drives and the second trial confirmed their success in addressing the initial hurdles.
Operation commenced in early November, with performance fine tuning continuing alongside. By the end of November 2019, the unloader was comfortably meeting the target train unloading time of three hours. By varying train speed over the unloader based on how the material was flowing, an unloading time of two hours could be achieved.
Valpreda praised the commitment of the team he led, saying, “the conditions were cramped and dirty, but the boys were fully committed to getting the job done, committing not only their labour but also their ideas of how we could solve the problems.”
“We have many people with a trade background who also operate equipment and that helps us to develop simple, practical solutions to problems we are faced with,” he says.
“The local community has been great in supporting our work. We stayed at the Royal Hotel and they had meals for us, even when we got back dirty and outside normal meal times. Central Crane Services were helpful when we needed cranes and handling equipment.”