PRESS RELEASE: The 54t scalping screen – measuring over 10m in length and with a 3.7m width – is a single-line unit that will handle about 7,000t of run-of-mine iron ore per hour. It will take feed from a primary crusher with a top size of 400mm, although the dimension of these boulders may still be up to 800mm long.

Kwatani CEO Kim Schoepflin commented: “This run-of-mine feed will place tremendous load on the screen, particularly due to the impact and weight of the oversize rocks.

“Significantly, a large portion of the material – as much as 50% of the feed – will move over the full length of the screen without passing through the apertures, so the screen must effectively ‘convey’ these heavy boulders without incurring damage.”

This also means that the bed depth will be relatively high, requiring the design to accommodate a bed of about 800mm of material on the feed end and about 500mm on the discharge end. Iron ore is a heavy material, so a bulk density factor of 2.5 has been applied to the design specifications.

Vibrating with a stroke that applies around five times the gravitational acceleration (5Gs) on the material, the mass of the rocks is effectively increased by five times, according to Kwatani’s chief operating officer Kenny Mayhew-Ridgers. 

“This places a very high requirement on the machine’s technical specifications and durability, so the mine has been very careful to choose a supplier that they trust completely to design and manufacture a unit of this capacity,” said Mayhew-Ridgers. “Even the panels had to be designed with internal structures, so they could withstand the magnitude of these forces.”

Schoepflin stated that the unit’s single-line status makes it a key item of equipment on site, with several parts of the process plant heavily reliant on its throughput.

“It is therefore vital that the screen runs reliably and continuously, as any stoppage will in turn disrupt the whole plant,” she said. “Uptime is an absolute non-negotiable.”