Replacing Ormeau’s aging processing plant
Ormeau is one of the company’s twelve Queensland based quarries. Centrally located approximately 30 km from the Gold Coast and 40 km from Brisbane, the site is placed within a major rock formation called the Neranleigh-Fernvale beds, a large zone consisting of massive to slightly foliated meta-greywacke with minor bands of shale and argillite. Originally owned by Quarry Industries, quarrying at the site began in 1981. A joint venture was then formed in 1987 between BMG Resources and Quarry Industries. This endured until Boral acquired Quarry Industries in 1994. Boral has been the sole owner-operator of the quarry ever since.
Queensland’s capital - Brisbane, is Australia’s third largest city with a population of around 1.2 million. Located between Brisbane and the border of New South Wales is the City of Gold Coast, Queensland’s second largest city. Connecting these two cities with modern infrastructure and catering for their rapidly growing population is driving the need for huge volumes of aggregate.
To help meet this demand, in 2017 Boral embarked on a project to replace Ormeau’s aging processing plant, quadrupling the quarry’s production capabilities.
Neil Bellamy, Boral’s Drill & Blast Manager - Queensland and Northern Territory, has been closely involved in the expansion, managing the operational readiness of the project and site interaction.
“The site has traditionally produced around 500,000 tonnes of quarry materials per annum. This included the supply of asphalt aggregate to Boral Asphalt in Southeast Queensland, a limited amount of concrete aggregates and manufactured sand to internal concrete customers, as well as other construction materials to the infrastructure and private sectors.” he said. “Over the next few years we will ramp up production at Ormeau to 2 million tonnes per annum.”
Designing the new plant to meet new requirements
Working around limited operating hours
One of Boral’s challenges for the expansion of operations at Ormeau was that the plant is only permitted to operate from 7 in the morning till 6 at night - Monday to Saturday.
“Because of restrictions to operating hours, and the fact that maintenance must be done within these hours as well, the plant has to have a higher per hour capacity to meet our 2 million tonnes per annum goal,” said Bellamy. “We also had to allow for ramp up and down times, as well as unplanned outages.
“In the end, we had to design the new plant to handle 1000 tonnes per hour. This was a challenge, because the engineering of the plant and the equipment within the plant were exponentially more expensive.”
“When in full production, the new plant will be Boral’s largest quarry operation in Queensland,” said Liam Elsworth, Quarry Manager at Ormeau. “It will play a key role in supplying various raw materials for Queensland’s burgeoning southeast region, and the state’s growing infrastructure needs.”
Metso engaged from the beginning
In 2017, Boral awarded Metso the contract to design, manufacture and supply an aggregate crushing and screening plant to support the increased throughput. Metso was heavily involved in the entire design process. Boral and Metso staff workshopped the plant’s process flow design and then selected the equipment that would handle the duty.
“Metso has brought a number of innovations to our circuit design” said Bellamy. “One example was the inclusion of a surge bin post the tertiary crushing station, which allows crusher output material to be metered to the tertiary parallel screening circuit. This results in optimal screening performance, which delivers a very consistent final product. From a particle size distribution perspective, we are achieving some of the lowest standard deviation results within Boral's quarry network".
“That’s something that I wouldn’t have thought of, but it has been great for our product quality. The standard deviation of product size per sieve is one of the best I’ve ever seen.”
Innovations in the crushing circuit
The Metso MX4 Multi-Action cone crushers are the latest design from Metso, automatically optimising the crusher setting and wear compensation in real time, bringing lower operating costs, higher uptime and consistent output.
“We made a business decision to purchase the new MX4 crushers, this is the first installation worldwide where MX4’s have been used in parallel as final tertiary crushers. So far, they have met all of our expectations,” said Elsworth.
A lot of time and effort went into getting the process control right – it’s more complicated than it looks. For the final product we went with Metso screens,” added Bellamy. “The Metso screens with Trellex rubber media are performing well. We’ve done some fine-tuning of the screen apertures and we’ve achieved very good efficiency.”
The crushing circuit is a three-stage system consisting of Metso's Nordberg® C160™ jaw crusher, a GP500S gyratory and three MX4 cone crushers. Metso also supplied the vibrating screens and feeders, conveyors, bins, hoppers and chutes.
The plant is highly automated, “The intent is that the control room will be un-manned, and the automation will see the plant running at capacity throughout each shift without the need for human intervention,” said Elsworth.
Safety and environment
Safety and efficiency benefits
The upgrade involved completely replacing the old processing plant that was designed back in the 1960s and had been moved to the site from its original location in South Australia.
“Because we built the new plant to today’s standards, it provides greatly improved safety,” said Bellamy. “The design incorporates the latest safety best-practices relating to; guarding, ingress, egress, etc. The modern automation and control system has a lot of safety functionality built in to it. For example, there are no risks of overflowing media because the system can perform carefully controlled ramp-ups and shutdowns.”
Not only was the plant designed to improve site safety, it has also been configured for convenient maintenance.
“The plant has been designed with full and easy access to crushers and screens. All the buildings have overhead cranes for maintenance,” said Boral’s Project Manager - Kai Kane. “A minimum number of different types of screens, all using rubber media, were used, to reduce our spare parts inventory.”
Energy efficiency is also greatly improved. One of the criteria for the design of the plant was that the incoming power feed should not need an increase in capacity.
“We didn’t want to upgrade the existing 4MW electrical in-feed,” said Kane. “All of the latest technology in the plant has allowed us to achieve that goal while still aiming to increase our plant output to 1000 tonnes per hour.”
Environmental compliance is a must today
Boral had to comply with a range of rigorous environmental requirements to gain approval to expand the quarry. An environmental plan to minimise impact on the local koala population was commissioned by Boral. The plan includes maintaining an offset area of forest on land that the company owns south of the site.
Boral has also won awards for Ormeau’s storm water management plan: one of the requirements was to ensure that the site can deal with a 1 in 10-year storm event.
“On the southern and eastern side of the site we have the Pimpama River,” said quarry manager Liam Elsworth. “Previously the lay of the land meant that a large storm event could cause significant flooding, so we had to raise the elevation of the lower part of the site by about 3 m, to make sure it was out of the floodplain. A 60 m buffer was also established between the river and the working boundary, which we planted out with over 40,000 trees.
“We have built a storm water catchment system with pumping facilities that allow us to pump water back to the pit for our use.”
Other major environmental considerations were the need to minimise waste, noise and dust.
“In relation to waste, there is none”, explained Kane. “The new crusher and screening technology means that nothing is wasted. All raw rock input is converted to product.”
The overall design of the plant also included enclosing the entire crushing and screening process in buildings.
“All the screens and crushers are enclosed for noise control, and there are areas of the plant where we use automated water sprays to control dust,” said Bellamy. “All conveyors are covered, and the screens also have dust encapsulation, even though they are in buildings. The secondary and tertiary crushers also have a foam dosing system, which works well and is automated and adjustable.”
The new plant with its cutting-edge technology has played a pivotal role in the quarry achieving its throughput requirements.
“The assets themselves are performing as we hoped and expected,” said Bellamy. “We have achieved our minimum performance requirements earlier than expected and we were able to quickly ramp up to 90% of capacity.”
“We have a very good relationship with the local Metso team,” he continued. “The Metso installation supervisor was very good to work with. He put in long hours making sure everything was right.”
According to Metso’s Australian Vice President, Aggregates – Shaun Fanning, the key to delivering this world class plant was the early collaboration between Metso and Boral to develop the design.
“While we have extensive experience in delivering aggregates plants around the world, Boral was able to bring valuable features into the design based on their operational experience,” he said.
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