First Quantum Minerals Ltd (FQML)’s Cobre Panama is well known as one of the largest new copper mines opened globally in the past decade. It includes open pit mining, a processing plant, a 300 MW power station and an international shipping port. At full current capacity, the plant can process 85 Mt per annum of ore to produce more than 300,000 t of copper per year along with gold, silver and molybdenum. Over the last 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.’ Commenting on his company’s involvement in the project, Vice President for Original Equipment at Schenck Process – Amit Parimoo said: “By the time we got involved, they 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.” 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.
Vice President for Original Equipment at Schenck Process – Amit Parimoo
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, Fields became involved in the Cobre Panama development and remains part of the team responsible for the mine’s ongoing success. Thinking back to the start of the project, Fields recalls the initial stages of the plant’s design: “When First Quantum bought the Cobre Panama mine and restructured the project, it was conceived for a 74 Mt per annum throughput. Mid-project, we increased that to 85 Mt/y by making some changes to the milling and flotation circuits, but there were already elements of the plant that were capable of 100 Mt/y. We always had the intention to ramp up quickly to 85 Mt/y and then stretch beyond that to 100 Mt/y,” he said.
One of three Beast SAG mill discharge screens at Cobre Panama’s processing complex
“Despite the challenges of COVID, we are currently doing well as we work towards our 85 Mt/y continuous throughput target. Also, over the last 6-12 months we have scoped some concurrent, complementary projects that should allow us to reach 100 Mt/y 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.
Aaron Fields, FQML Project Manager
The new screening facility will require three screens each capable of handling up to 8,000 t/h 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 they had with the supply and performance of their mill discharge screens, FQML once again approached Schenck Process for assistance. Fields comments: “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.”
Two overland conveyors deliver material from the primary crushers to the secondary crushers
Responding to FQML’s requirements, Schenck Process’ Australian based engineering team created anew 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 m wide and 9.7 m long. Like Schenck Process’ 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 t cranes, allowing our teams to safely handle very large equipment with ease. With a total transport mass of around 89 t, these huge screens will challenge our facility’s impressive lifting capability,” said Parimoo.
