At the B2Gold Masbate Mine in the Philippines, grinding efficiency is the top priority and the SAG mill is the key to achieving it. In 2017, B2Gold raised the annual production target from 6 to 8 million tons while setting out to maintain the same 2.4 complete mill relines per year. This meant that the existing Poly-Met lining had to be replaced with a lining more than capable of handling the higher wear rate.
“We knew that we needed a steel lining. But because it is so heavy, we didn’t want to use it for the whole lining. Metso then came up with a hybrid concept by combining several materials such as steel, Poly-Met, rubber and ceramics to keep the weight down because excessive weight burns and consumes your mill power for no real gain. Less weight protects your bearings and your driveline. It also allows you to get higher throughput without adding extra mill weight,” says Jason Ives, Senior Maintenance/Mill Advisor at B2Gold Masbate.
By combining different materials, the individual liner components could be positioned in high, medium and low impact grinding zones. It enabled the use of high-profile heavy-duty steel lifter bars in the high wear zones and prevented overloading trunnion bearing capacity. Metso’s capability in supplying a unique mill lining design with several materials, a well-defined optimization plan and a regular presence on site also made the choice of supplier much easier to make. In addition, by rolling all these elements into a Metso Life Cycle Services (LCS) contract, it made the decision easier for the mine to proceed with the project.
The first lining was installed in February 2019. To accommodate Metso’s heavy-duty liner in the 32’x14’ SAG mill, a Metso field services team from Indonesia was deployed to re-drill a larger liner bolt hole diameter in accordance with Metso OEM metallic liner fastening standards.
“Metso is the only one who can supply the mill lining solution we want, and they can provide engineering back up. We want the whole package – from the mill lining design, engineering team and service team, together with a competitive price – and these
factors determined our choice of supplier. Others simply do not have that in depth engineering knowledge design team,” explains Jason. But technical knowledge or innovative products would amount to nothing if service quality is sub-par. “We want to be able to ask specific questions and get a quick response. They certainly do follow up very closely and respond promptly. I am very pleased.”
The mill lining in use is still the initial design, but the results have started to show.
“We thought four million tons was a lot because previously, we were lucky to get three. However, we have experienced significant improvements in wear life on most parts of the lining. Everything except the shell lining have exceeded the targets with a wear life of more than 4 million tons. That’s a distinct advantage already seen with just the first set of liners,” notes Jason…
Read the entire article on metso.com: B2Gold Masbate Mine increased mill uptime with unique lining design and improved throughput by 33%.
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