It is now a full century that mines and industry have been relying on Linatex rubber products from Weir Minerals to protect equipment from abrasion, impact and corrosion. “The remarkable qualities of natural rubber in a range of demanding mining and processing applications have made Linatex integral to our customers’ success over the past 100 years,” says Boitumelo Zimba, Rubber Product Manager at Weir Minerals Africa.
“The product breakthrough which has differentiated us in the market is our proprietary liquid phase compounding (LPC) process. This is a gentle process that retains all the valuable qualities of the high quality natural latex which is our central ingredient.”
The more common processes, used by competitors in the market, effectively change the molecular structure of the natural rubber, resulting in shearing that undermines the resistant qualities of the final product, she explains. By contrast, Linatex Premium Rubber exhibits outstanding strength, resilience and resistance to cutting and tearing, giving superior performance in wet abrasion conditions.
“The LPC process gives us a product that is 95% natural latex. We are the only company producing rubber this way,” she says. The applications are well known, from impact liners in transfer chutes to abrasion resistant lining in pumps and hoses. Over the decades, the applications have broadened as the company applies its research and development to various potential modifications.
Over the course of the last century, there have been plenty of success stories in mining. What has become increasingly crucial, however, is the quantification of the benefits that Linatex Premium Rubber can bring to specific applications, argues Boitumelo. As mining embraces increasing levels of technology and digital monitoring, it becomes easier to monitor equipment performance and cost of ownership.
“One of our mining customers in central Africa needed to extend the service life of their tailings pipeline,” she explains. “Due to the abrasion resistant qualities of our Linatex Premium Rubber, the customer was able to save over US$110,000 per annum on their tailings pipeline, after ceramic liners were replaced by a 12mm layer of our product.”
This meant that the pipeline would last 36 months instead of nine months, reducing the cost of liner replacement and downtime. In another successful application, Weir Minerals Africa used a nitrile-based rubber compound in a mining customer’s flotation tanks, which were previously lined with ceramic tiles. The results were again dramatic, increasing the replacement intervals from two months to 36 months. “This ultimately saved that customer almost US$570,000 a year, reducing downtime considerably,” she says.
No patch required
In another successful application, Linatex modular panels has solved the challenge of high wear rates on a mine’s hydrocyclones in Kazakhstan. KAZ Minerals’ Bozshakol copper mine was facing difficulty with wear rates on the rubber and ceramic-lined launders in its primary hydrocyclone clusters. This resulted in costly downtime every two to three months, when time-consuming rubber patching would have to be carried out by the Bozshakol maintenance team.
After conducting 3D scanning of the cyclone cluster launder, Weir Minerals wear experts proposed the wear resistant 25mm Linatex steel-backed bolt-down modular panels with high open area. The modularity of these panels allowed KAZ Minerals to replace the worn parts one by one, without the need to patch-repair.
The Linatex modular anti-abrasion panels were installed in October 2019, and it was an impressive 21 months before some of the panels were finally ready to be replaced. This meant an increase in wear life of 584%, saving on downtime as well as on about 450 labour hours in maintenance. The success achieved at Bozshakol led other KAZ Minerals mines to also order these panels.
High wear rates
At its copper, gold and silver mine in the Grasberg minerals district, PT Freeport Indonesia was also experiencing the challenge of high wear rates. In this case on its SAG mill discharge box dart valve seat liners. With the incumbent liners lasting only three months, the mine was forced to conduct early shutdowns as the SAG mill maintenance interval was every six months.
The Weir Minerals solution was to introduce superior Linatex rubber material and mould the product into the existing dart valve seat configuration. The team also re-engineered and
introduced a taper shape to give extra impact absorption for the rubber-lined product. This extended its life to up to seven months, allowing the SAG mills to run uninterrupted for the full six months between scheduled shutdowns.
The specialised science of processing natural rubber latex has been maintained at the company’s global production facility in Kuala Lumpur, Malaysia. The supply chain for the natural rubber is also based on sustainable principles, ensuring that the trees are not destroyed and that the harvesting process is environmentally responsible.
“As the most significant input to the Linatex products, the latex we use is tested extensively before processing; first at our suppliers’ facility and again at our manufacturing facility,” Boitumelo concludes. “Each batch of rubber produced is sampled and tested, and customers have the option to request a product test certificate.”