Safety

Passion for continuous improvement: The Mount Bundey crushing project

The Metso Excellence in Crushing and Screening Award was offered in 2016 to IQA members for the implementation of a process change to a plant that resulted in improved productivity, energy efficiency or cost savings.

{{image2-a:r-w:300}}The recipient was Northern Territory member Phillip (Dick) Pallisier who oversaw a crusher optimisation project at Boral’s Mount Bundey Quarry, both in conjunction with his team and the OEM Metso. The quarry is about 100km from Darwin.

Pallisier has been involved in the quarrying industry for 35 years, 27 of those with Boral. “I started with a private construction company in Amby, a small country town in western Queensland, and I worked for them for eight years,” he told Quarry. “This company closed down and I took a different direction until the opportunity then came up to work for Road Surfaces Group at its Amby quarry. Road Surfaces Group was then acquired by Boral, for whom I have worked for the last 27 years in various roles and locations, including Brisbane, Roma and Longreach. In 2008, I relocated to Darwin.”

In 2009, as general manager of Boral’s Mount Bundey Quarry, Pallisier oversaw the commissioning of a crushing and screening plant with an output of 250 tonnes per hour (tph), followed by major operational improvements from 2010 to 2012 with changes in raw feed from granite to hornsfels, and back again. This saw the plant optimised to 278 tph for fine crushed rock (FCR, or roadbase) and 262 tph for aggregates.

From 2013 to 2016, Pallisier also managed the efficient supply of more than one million tonnes of aggregate to the Icthys Project Onshore LNG Facilities, and another one million tonnes to the associated infrastructure boom in the Northern Territory. This was remarkable given the site had never previously produced more than a monthly average of 30,000 tonnes.

At the peak of the Icthys LNG project, the Mount Bundey plant employed or contracted up to 30 personnel and had an output of 100,000 tonnes per month. Nine employees now man the plant and its output is steady at 250,000 tonnes per annum. It continues to produce concrete and sealing aggregates, construction, drainage and bedding materials, plus manufactured sand.

ELIMINATING BOTTLENECKS

It was during the peak period, in June 2015, that Pallisier initiated the FY16 crusher circuit optimisation project as part of Boral’s annual Value Improvement Project ideas phase. He proposed that the throughput of the crushing and screening plant – comprising a C110 jaw crusher, a GP200S secondary crusher and a GP300 tertiary crusher in a closed circuit with a 6m x 3m Terex screen, plus a Barmac vertical shaft impactor (VSI) – could be improved by up to 10 per cent. This would reduce costs by up to $160,000 per year.

Pallisier credits Boral for the opportunity to “develop, maintain and improve a safe and productive quarry operation”.

{{image3-a:r-w:300}}He said: “Boral is a progressive company which encourages continuous improvement while maintaining a safe and diverse workplace in line with our zero|one|ten strategy. Our focus is on zero harm for our people, being number one for our customers and employees, and striving for 10 per cent improvement every year.”

From July 2015 Pallisier ran workshops with operators to identify bottlenecks in the crusher circuit and devise ways to solve them, and he consulted with Metso on best practice and optimisation ideas. He also set up systems to monitor beltweigher traces to understand spikes and surges that might affect production. Most importantly, it was decided that the optimisation process would be implemented during the Christmas 2015 shutdown, at a time of least disruption to customers.

The two main bottlenecks within the crushing circuit were the capacities of the Barmac VSI and the secondary and tertiary crushing plant.

The Barmac’s FCR throughput was limited to 200 tph and surges in the throughput rate regularly caused stoppages or overflow. Excessive bypass of the Barmac VSI also affected the seal aggregate shape.

It was decided that the best way to address the first bottleneck was to increase the Barmac’s capacity and relieve the load.

{{image4-a:r-w:300}}A new bypass chute and lid were built in November 2015 – the chute to increase the bypass for FCR, and the lid to raise the height of the chamber and cascade the material. These changes would not eliminate overloading, but the load pressures could be reversed. The chute and lid were installed in just two days during the Christmas shutdown.

The chute was also split at the bottom deck of the control screen, and a hydraulic bypass installed, to allow FCR (from -22mm to +4.75mm) to be scalped out prior to the Barmac VSI. A new chute system was designed to allow the diversion of product to the FCR belt, enabling all aggregates to be passed through the Barmac to improve shape.

The second bottleneck lay in the secondary and tertiary crushing circuit, which was restricted to less than 280 tph without overflowing the GP200S and the GP300. Bottlenecks in the GP300 caused the primary crushed rock to be turned on-off by the automated plant, resulting in inconsistent throughput rates.

In consultation with Metso, Pallisier and his team increased the stroke settings of the GP200S and GP300 from 25mm to 32mm. To reduce loading on the GP300, its feed size would also be reduced from 45mm to 38mm top size. In turn, to avoid the bottleneck passing from the GP300 to the GP200S once the improvements took effect on the former, the latter’s stroke was also modified and repairs to the tapers on the mainframe were implemented.

Changes to the GP300’s stroke setting occurred in July 2015, while the GP200S’s stroke was altered as part of an in-situ rebuild in March 2016. This was a couple of months after monitoring of the plant had confirmed the GP200S’s new stroke setting would be effective.

Pallisier and his team also decided to automate the primary C110 jaw crusher, which was the only part of the crushing and screening circuit that wasn’t computerised. As a result of production rate improvements made between 2012 and 2015, personnel had identified that the C110’s manual control created unwanted surges in production throughout the plant’s automated parts. As a result, in December 2015, after further consultation with Metso, the C110 was equipped with sensor options and programmed with Citect operating and monitoring software.

TESTAMENT TO RESILIENCE

The FY16 crusher optimisation project was completed between July 2015 and March 2016 at a cost of $60,000. The total cost was $20,000 below Pallisier’s original projections.

{{image5-a:l-w:300}}The most expensive aspects were the new Barmac lid and bypass chute (about $25,000), the modified gates to relieve the load to the Barmac (about $10,000), the installation of new chutes in the Barmac section to allow for simultaneous production of FCR and aggregate (about $15,000), and the automation of the jaw crusher (about $10,000). Increases to the secondary and tertiary crushers’ stroke settings were completed at no additional cost during a routine strip and inspect session.

The project achieved significant improvements in throughput – 23 per cent for aggregates (from 262 tph to 322 tph) and 33 per cent for FCR (from 278 tph to 369 tph). Whereas Pallisier thought he would achieve cost reductions of $160,000 per year, the crusher optimisation project is estimated to have achieved savings of up to $500,000 per year. There were also benefits in improved manufactured sand grading and consistency of aggregate grading and shape.

In nominating Pallisier for the Metso Excellence in Crushing and Screening Award, the previous general manager for Boral in the Northern Territory Travis Potts described the Mount Bundey crushing improvement as “the best planned, budgeted and executed project I have witnessed”.

Potts said: “The project was entirely initiated and executed by Dick and his team. He used targeted technical support from OEM Metso and planning/budgeting reviews by myself as required.

“During this time, the site was still operating at high capacity to supply the Icthys Project Onshore LNG Facilities – which was successfully delivered on time, on budget, without a single quality issue for greater than two million tonnes.

“Darwin is also a notoriously difficult place to operate due to labour/skills shortages, costs of operations and tyranny of distance.

“The project created innovative solutions such as hydraulic gates on chutes, which could be applied to most quarry sites. Dick managed the project during the peak supply of the second largest project in the country, in some of the most difficult operating conditions in the country. The results are truly a testament to resilience, commitment and passion to continuous improvement.”

Pallisier told Quarry that it meant a lot to him and the Mount Bundey Quarry staff to have received the Metso Award.

“I would like to thank the IQA and Metso for the Excellence in Crushing and Screening Award and the opportunity for further knowledge, awareness and improvement,” he said. “The recognition of achievement by Metso and the IQA confirms that improvements can be made to optimise our productivity and therefore increase our supply capacity no matter the size and remoteness of the business.”

The award entitles the recipient to undertake an overseas study tour and Pallisier said he would use it to visit one of Metso’s manufacturing plants in Europe and nearby quarries.

“I have some ideas on improvements in production for Mount Bundey Quarry and Boral’s Northern Territory operations and I would like to see how this could be achieved and what may be available to assist with the processes,” Pallisier said.

To find out more about the IQA Awards, and how to apply or nominate a colleague or business, visit quarry.com.au/Networking/Awards/2017AwardInformation.aspx

Applications and nominations close on 31 August, 2017.

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