A softer approach to mineral extraction


A softer approach to mineral extraction

By using a special-grade rubber compound in place of composite steel, Trelleborg has helped improve the efficiency and ease of operation of grinding mills without compromising performance.

The process of extracting minerals from ore takes a heavy toll on milling machines as well as on mill planners and operators. Mills use high-impactforces to crush the ore fed into them, and as a result they tend to be noisy and prone to accelerated wear and high energy consumption.

But a recent breakthrough by Trelleborg’s team in Australia promises to reduce mill energy consumption, wear and tear ,and noise levels, while increasing efficiency. A trial at an operation in Australia has yielded impressive results, and a second trial is now well under way.

Zane Thomas, Technical Manager for Mills at Trelleborg Offshore & Construction in Australia, says the new concept involves the use of a special-grade rubber compound in the lining of ball mills that replaces the steel and composite steel solutions that have traditionally been used.

“The new solution is lightweight, as well as quicker and easier to install,” he says. “It reduces load and power draw, is not prone to cracking and allows for predictable wear life monitoring.”

Mills are used to crush and reduce the size of ore to enhance mineral extraction, Thomas explains. One of the most commonly used mills is the ball mill in which the ore is placed in a cylindrical shell with heavy steel grinding balls (the grinding media) and rotated. The weight of the falling balls pulverizes the ore, allowing for the next stage of processing.

Improved milling process

Typically, the inside linings of primary and secondary grinding mills are made of steel or composite steel. Because of the high impact and abrasive nature of milling operations, the liners must be replaced regularly.

Trelleborg recognized that the milling process could be improved for some primary and all secondary and tertiary milling applications. The company’s operations in Australia used a highly durable rubber product (1605AM) to create a new lining system for the mills. Rather than the composite steel approach, the system relies on rubber lifter bars and shell plates to do the job.

When trialed at an Australian mining operation in 2013 and 2014, the system produced outstanding results. The rubber liners proved just as durable as composite steel liners, and their much lighter weight greatly improved ease of installation.

“Trelleborg has a mindset of continuous improvement, and this was part of that policy,” says Thomas. “Our mining team considered the challenges mill operators were facing and came up with a solution that would help clients and develop the mining business globally, in terms of both milling applications and other highwear areas.” 

Global potential 

In addition to its other benefits, the new solution reduces wear and tear on the most expensive part of the milling operation, the grinding media. It also eliminates the potential of liners and inserts cracking, something that can pose a hazard to operation and lead to losses from unnecessary downtime.  

The global potential for such a product is enormous, Thomas says. Following the success of an initial trial with a mining client, a full set of linings has been installed to revalidate the results of the trial.

This is an article has been reproduced from Trelleborg's T-Time magazine. To download the latest edition, go to: www.trelleborg.com/t-time 

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