The Southern African Institute of Steel Construction (SAISC) has announced that its member company, structural steel fabrication contractor VIVA Engineering, based in Kempton Park, Gauteng, has been nominated in the Mining/Industrial category for the SAISC Steel Awards 2024 – for its role as the constructor of 11 extra heavy duty belt feeders for client Virta Inc.
The feeders form part of the bulk materials handling scope of the huge $4.4 billion Nueva Centinela project that was given the green light by Antofagasta Minerals (AMSA) in December 2023, with Virta having been awarded contracts for both feeders and conveyors. The Centinela Second Concentrator Project will produce an additional 170,000 copper equivalent tonnes per annum, comprising 144,000 t of copper production, 130,000 oz of gold production and 3,500 t of molybdenum production, with a 36-year mine life based on Centinela’s substantial ore reserve of two billion tonnes. The new project will have lower net cash costs through an increased focus on concentrator capacity that incorporates modern technologies, increased by-products and greater economies of scale.
The 1,829 mm x 17 m long belt feeders were designed by Virta Inc and constructed at VIVA Engineering then shipped to Chile, where they will be used by Centinela to handle extraction of copper ore underneath the main ROM stockpiles.
The VIVA scope included feed chutes, skirts, discharge chutes, and the mainframe. The feeders use an all welded construction for maximum strength. VIVA started the 600 km, oversize transport of the 50 t-plus feeder units on July 29, with three units delivered to Durban on July 31 following by the remaining eight units with the last five units delivered by mid-August to the port from where they were shipped onward to Chile.
Virta states: “A project like this – from detailing and fabrication through pre-assembly, belt splicing and modular transport – was initially envisioned to require up to nine months, yet with world-class team dedication, collaboration and VIRTA’s partnerships with VIVA, Lorbrand, and Semperit, we completed the full scope in about six months.”
Each feeder was structurally engineered not only for its operating application but also for strength and rigidity under unitised lifting, as each unit makes its way by truck, then ship, then truck to the site in Chile. The feeders were loaded onto the trucks in the VIVA yard with a 220 t crane.
Virta was awarded the design, supply, pre-assembly and delivery of three types of feeders (11 total) for handling of coarse, intermediate and fine ore. The scope included all mechanical and structural engineering, DEM chute design, steel fabrication (frames, hoppers, chutes, spile bars) and supply of all idlers, pulleys, belt and hydraulic drives. Structural engineering included strict adherence to Chilean design codes for operation in one of the most seismically active areas in the world.
Major equipment includes Lorbrand pulleys and idlers, Hagglunds hydraulic drives ranging from 400 to 550 kNm torque, and Semperit ST4000 and ST4500 steel-cord conveyor belt imported into South Africa from Poland.
Virta says it partnered with the VIVA team to perform steel detailing, 3D modelling, fabrication, pre-assembly, rigging and logistics coordination. The VIVA logistics team managed all necessary local logistics, assembly crews and oversize-load transport permitting. The pre-assembly at VIVA included idlers, pulleys and steelcord belt splicing. With the installation and alignment of large components and splicing of the steelcord belt in a controlled, efficient shop environment, Virta says this innovative and optimised pre-assembly strategy significantly reduces site installation time, schedule and risk.
