Saturday 24th Jul, 2021

Unleashing the beast – new mega screens for major copper producer

Schenck Process has created one of the largest multi-slope banana screens ever to be built, rivalling its predecessor ‘the Beast’.

Canadian-based First Quantum Minerals Ltd (FQML) is one of the world’s leading copper producers, exporting to customers worldwide. While its focus is on copper, FQML also produces nickel, gold, magnetite, zinc, and other by-products. The company operates mines in several countries and employs around 20,000 people world-wide.

With its history dating back to the mid 1990’s in Africa, the company has steadily grown, largely through project development and acquisition. In 2010, FQML made four acquisitions, which included Trident/Sentinel in Zambia and Ravensthorpe Nickel in Western Australia. Following a corporate acquisition in 2013, First Quantum assumed an 80 per cent equity interest in the Panamanian company that holds the Cobre Panama concession. Since then it has increased its interest to 90 per cent.

Spanish for ‘Panama Copper’, Cobre Panama is one of the largest new copper mines opened globally in the past decade. Located 120 kilometres west of Panama City, the production complex includes open pit mining, a processing plant, a 300-megawatt power station and an international shipping port.

At full current capacity, the plant can process 85 million tonnes per annum (mtpa) of ore to produce more than 300,000 tonnes of copper per year along with gold, silver and molybdenum.

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Although FQML’s head office is in Canada, the company also has offices in the UK, Australia and South Africa. FQML’s Australian office has been described as the ‘epicentre’ of the company’s projects capabilities.

Over the past few years, the company has commissioned the design of some of the largest mineral process equipment ever made. In 2017, First Quantum approached Schenck Process regarding the supply of mill discharge screens for Cobre Panama’s SAG mills, which are among the biggest in the world. The resulting design was a monster mill discharge screen, that was later dubbed the ‘Beast’.

Amit Parimoo, Vice President for Original Equipment at Schenck Process, says that by the time Schenck got involved, FQML were already quite advanced with the design and construction of the plant

“As well as designing a screen that could handle the throughput volume from the mills, it also had to fit within a tight footprint. That was the most challenging part for us,” Parimoo says.

Schenck Process delivered three of these screens to Cobre Panama in 2018 and the processing plant went into commercial production in mid-2019. The same screens were subsequently retrofitted at First Quantum’s Sentinel operations in Zambia.

Based within FQML’s Projects Group in West Perth, Project Manager Aaron Fields is a professional mechanical engineer with more than 25 years of experience managing mineral processing projects in both Australia and overseas. Having joined FQML in 2017, Aaron became involved in the Cobre Panama development and remains part of the team responsible for the mine’s ongoing success.

“When First Quantum bought the Cobre Panama mine and restructured the project, it was conceived for a 74 mtpa throughput,” Fields says.

“Mid-project, we increased that to 85mtpa by making some changes to the milling and flotation circuits, but there were already elements of the plant that were capable of 100mtpa. We always had the intention to ramp up quickly to 85mtpa and then stretch beyond that to 100mtpa.

“Despite the challenges of COVID, we are currently doing well as we work towards our 85mtpa continuous throughput target. Also, over the last 6 to 12 months we have scoped some concurrent, complementary projects that should allow us to reach 100mtpa and beyond.”   

One of these improvement projects involves the installation of a new screening facility between the complex’s primary and secondary crushers. The intention is to minimise fines in the feed to the secondary crushers, freeing up valuable crusher capacity. The installation of a third secondary crusher is also planned.

The new screening facility will require three screens each capable of handling up to 8000 tonnes per hour of primary crushed ore, with the oversized material feeding the secondary crushers and the undersized material bypassing the crushers and heading directly to the grinding mills.

Based on the positive experience that FQML had with the supply and performance of the mill discharge screens, the company approached Schenck Process for assistance.

“When we develop a good relationship with a supplier and they prove to be what we would like them to be in terms of technical innovation and support, we tend to go back and work with the same people.  This was definitely a factor in our decision to work with Schenck Process on this project,” Fields says.

Responding to FQML’s requirements, Schenck Process’ Australian based engineering team created a new hybrid design which it says will be the largest multi-slope banana screen ever to be built. The result is a screen that measures 4.3 metres wide and 9.7 metres long.  Like Schenck Prosses Beast SAG mill screens, the excitation force of the new SLD4397DXX ‘mega’ screen is delivered by four DF704 exciters mounted on two unitary beams. But unlike the Beast, the new screen’s drive assembly incorporates a unique twin gearbox arrangement driven via a single motor, ensuring effective exciter phasing.

FQML’s Board gave the greenlight to Cobre Panama’s improvement project in December 2020. Pleased with Schenck Process’ new design, in January FQML awarded the company an order for the three new screens. These huge machines will be built at Schenck Process’ new Jandakot production facility in Western Australia and are expected to be shipped to site by the end of 2021.

“We are really pleased to be chosen to play such an important role in the ongoing success of Cobre Panama. Our purpose-built production facility in Jandakot is equipped with four 40 tonne cranes, allowing our teams to safely handle very large equipment with ease. With a total transport mass of around 89 tonnes, these huge screens will challenge our facility’s impressive lifting capability,” Parimoo says.