South African Solution for Australian Iron Ore Screening

As appeared in Modern Mining April Issue 

An innovative high-impact screen panel developed by Multotec has boosted the wear life of screens at almost a dozen iron ore mines in Australia’s Pilbara region.

So successful was the Ceradox panel that after testing was concluded on one mine site, the solution has been rolled out to 10 more mines in recent months. The installation of the Multotec Ceradox panels is driving up production targets by improving operational efficiency and productivity. 

According to Multotec screening product manager Shawn Faba, the initial request was for a panel with a wear life that would align with the mine’s regular shutdown cycle of 12 weeks. “Mines are constantly looking for ways to reduce downtime,” says Faba, “and the planned maintenance shutdown is one vital element in this strategy.”

It was therefore vital to lengthen the service life of the panels in the impact area of their scalper screens. These screens separate iron ore material less than 100 mm from oversize material, and operate under conditions that are both aggressive and abrasive. Wet scrubbing plants discharge material with a particle size of up to 300 mm from a discharge height of up to three meters. 

With standard rubber impact panels lasting only six to eight weeks, the plant was incurring significant unplanned downtime for unscheduled panel replacements. It was necessary to make a substantial improvement in the meantime between failure (MTBF) of the panels.

“Through a research and development collaboration between Multotec South Africa and Multotec Australia, the Ceradox panel was developed for application on the scalper screens,” Faba says. “This solution embodied the respective qualities of Hardox and alumina ceramic tiles, embedded in our tried-and-tested, world-class rubber formulation.”

The R&D and manufacturing effort drew on 50 years of Multotec expertise, gained in iron ore and base metal plants on three continents, says Faba. The product developed and installed is a 305 mm by 305 mm (1 foot) modular solid impact panel with forged plate inserts – or Hardox blocks – and ceramic alumina tiles, moulded in an impact-resistant rubber compound. 

“The Hardox blocks protect the ceramic leading edge, while the ceramic tile provides abrasion resistance,” he says. “Together with the rubber energy absorption, the 100 mm thick Ceradox panels aimed to achieve an improved service life of 12 to 14 weeks.”

As part of Multotec’s R&D campaign, the panels were tested for three months in the customer’s operation, starting in September 2019.

“The Ceradox solid impact panels exhibited excellent wear life and significantly extended the shutdown cycles, giving increased productivity to the screening equipment,” he says. “This greater availability of process plants is what we pursue in our partnerships with customers.”

The customer’s target was for the panels’ increased wear-life to allow mine production to improve to about 6 million tonnes per annum by the end of the 2019 financial year. As it turned out, the results exceeded expectations, with a wear life of 24 weeks being achieved. 

An added benefit of the new Multotec Ceradox panel is that it is 25% lighter than the equivalent Hardox panel, easing the burden on the screens and thereby contributing to the lower total cost of ownership. They are also fitted easily, with a simple pin-and-sleeve design with knock-through pins; the changeouts are also more predictable due to the patented wear-indicator system.

“This system helps operators by providing them with a simple, visible panel life indicator,” Faba says. “Providing a clear indication of each panel’s condition reduces the need to remove all the media on the screen.”

Multotec undertakes the local manufacture of the Ceradox panels at its extensive facilities in Gauteng. From here, they are exported to customers in Australia on a regular basis, where the Multotec Australia operation holds the required levels of stock. 

Faba emphasises that the high-volume manufacturing facilities make for short lead times. Where components demand longer lead times, as is the case with alumina ceramic tiles, substantial stock is ordered in advance and held in readiness.

The production facilities also include a rubber mixing plant, manned by in-house rubber specialists. Here, fit-for-purpose rubber compounds can be formulated and manufactured to meet specific customer requirements. The plant’s compression moulding technology, which involves a longer curing time, also contributes significantly to better wear resistance in the final product.

“Our strong supply capability allows us to deliver batches of 100 Ceradox units in a week to our customers anywhere in the world – to meet their shutdown deadlines,” he says. “We can also manufacture different thicknesses of the Multotec Ceradox panels, from 50 mm to 100 mm.”

Faba emphasises the importance of Multotec’s philosophy of being close to the customer’s operation. This, he says, is to properly understand both the performance requirements and the specific conditions under which equipment must perform. 

“We are unique in our service offering to customers, in that we offer a total solution which can address the optimisation of screening performance, as well as service and maintenance,” he says. “Alongside this expertise and product offering, we frequently visit our customer sites. This allows us to assess the various issues that hamper screening efficiencies, and we can gather the data we need when we formulate the necessary solutions.”

Such has been the success of Multotec’s operations in Australia’s iron ore producing region that the company now supplies about 35% of the screening media to mines in the Pilbara area. He notes, however, that constantly changing mining conditions are always presenting new demands that must be met.

“Changing geology, for instance, is an ongoing challenge to mines and their technology providers,” says Faba. “This makes it vital that we partner closely with customers at all times to understand the particular ore bodies and their process requirements. We can then bring our R&D and manufacturing capability to bear on the challenges.”