The quarry manager, Matt Neil, had used 20mm thick cross-tensioned rubber screen cloths on the top deck of his Austral 5m x 2m primary screen for as long as he could remember.
Installation of the heavy cross-tensioned rubber screens was quite difficult, with a mobile crane required to lift 20mm screen cloths weighing in excess of 60kg up to the working platform before being manhandled into position on the screen.
Removal of the worn cloth was equally difficult, also requiring several men to wrestle with and lift the cloths out of the screen box.
Neil’s primary concern was the health and safety of his workers given the frequent replacement intervals of the heavy rubber screen cloths.
This prompted him to investigate safer, lighter alternative options. He subsequently chose Nepean Rubbers’ Eazi-fit modular system because he could convert his screen to a modular arrangement without costly frame modifications.
Each 60+kg and 20mm thick cross-tensioned rubber cloth on the screen was subsequently replaced with four smaller 40mm thick Eazi-fit rubber panels, each weighing less than 20kg. The lightweight panels could be easily and safely carried up to the screenbox without the need for heavy lifting equipment.
Custom-designed panels
The Eazi-fit panels are custom-designed to suit the existing structure of a screen, and the modular panels can even be used in conjunction with cross-tensioned rubber, polyurethane or wire screen cloths.
As with every screen cloth installation, regardless of the type, it is important to check the support bars are in good condition and the screen crown has a good even radius. A stringline is usually all that is required to check the crown radius.
When all necessary repairs have been carried out, with the frame cleaned and new capping rubbers fitted, the Eazi-fit panels can be placed on the screen frame where the cross-tensioned cloths previously sat. The centre hold down bar is then fitted with bolts only finger tight.
The old steel side clamping bars are replaced with long wearing Eazi-fit rubber side clamping bars. When the Eazi-fit side clamp is in place, the centre hold down bar bolts can be tightened. The job is done and conversion is complete.
Increased throughput
Creating a safer working environment was Neil’s main objective with the conversion to the Eazi-fit system, but increased screening efficiency was a secondary requirement.
The increased throughput post-conversion initially resulted in a little too much material passing through the top deck panels, starving the secondary crusher and loading up the tertiary crusher. Some subsequent crusher adjustments optimised the flow and a blend of slightly smaller aperture screen panels was systematically installed to fine tune the balance of feed for even better efficiency.
The 20mm thick cross-tensioned screens typically last about four months. After three months of operation, if the Eazi-fit panels are showing minimal wear, they may last a further six to nine months.
The prospect of double or triple the wear life with no screen box modifications, plus the ability to quickly switch back to cross-tensioned cloths should circumstances change, made the Eazi-fit system a sensible, low risk and cost-effective choice for Neil.
“The longer wear life means boys aren’t climbing in the screens to change out worn cloths, which by far is not their favourite job. I couldn’t be happier!”
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BENEFITS OF THE EAZI-FIT MODULAR SYSTEM |
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Source: Nepean Rubber