Kumba Iron Ore’s Kolomela mine in South Africa has reduced crusher liner replacement downtime and improved safety using a concave carousel and removal trays system provided by Metso, the mining equipment manufacturer reports.

Located in the Northern Cape Province, Kolomela contacted Metso for assistance in reducing its primary gyratory crusher concave liners replacement time.

The mine produces over 13 Mt/y of iron ore and is one of Kumba’s (majority-owned by Anglo American) largest operations in the country.

In mineral processing, crusher efficiency can be compromised over time, affecting production time and, most importantly, the safety of employees, Metso said. A major factor affecting crusher efficiency is the amount of downtime. The longer it takes to replace the wear parts inside the chamber of a primary gyratory crusher during a maintenance shutdown, the less uptime and, thus, less production. By reducing the number of lifts, the replacement can be done much faster and safer, according to Metso.

Kolomela approached Metso’s expert team to help it reduce the average downtime the operation encounters when replacing concave liners of their Superior SG60-110 primary gyratory crusher.

Metso’s Regional and Technical Support Manager Crusher Wears, Andrew Stones, said: “When the mine approached us with a request to help them speed up the process of changing the concave liners on the primary gyratory on site, they asked us to replicate the methodology that we once used at one of Anglo American’s major copper mines in South America, Los Bronces, which included the use of special tooling such as carousels and removal trays to remove the liners.

“Following the review of the Los Bronces system, we identified that we used different parts and installation methods not suitable for Kolomela’s operating model.”

Metso’s team looked at an alternative solution not only for different fixing arrangement on the carousels, but also changed parts. Instead of the mine having six rows of concaves to install, Metso reduced the rows to four. This minimised the installation time, according to Metso.

In addition to this, the team supplied Kolomela with removal trays – which enable a faster removal of the worn segments – as well as with modified attachments to help lift and install the carousels.

Metso’s solution has reportedly halved the downtime required for a concave liner change, but reduced downtime was not the only value add provided; the mine also reduced the injury exposure rate by 95%, according to the company.

Metso said: “Unlike the previous system that the mine used, which required people to be in the crusher when lowering each concave, Metso’s innovative carousel system provided optimised operating labour and safer installations. It is not dependent on human interaction.”

Kolomela’s Section Manager Engineering, Pieter Malan, said: “At Anglo American, we are unconditional about the safety of our colleagues. When the Metso team highlighted the safety element that the carousel methodology brings, it was indeed an added benefit and advantage. We understood, at that point, that Metso will also prioritise the safety and well-being of all individuals. There is no price on safety.”

Metso’s Vice President Mining, Africa and Middle East, Qasim Abrahams, said: “Previously, the Kolomela mine used 288 lifts to remove and install each concave liner; a process that has been identified as potentially hazardous work for the liner replacement team. Our new concave carousel concept reduced the lifts to 16, substantially improving both uptime and safety. The carousel allowed an entire tier of new concave segments to be lifted in place at once.”

Metso’s relationship with Kolomela was established in 2010, when the company provided the mine with the installation and commissioning of its crushers and the supply of original equipment manufacturer spare and wear parts. Other Metso equipment on site include two MP800 cone crushers and one MP1000 cone crusher.

Metso said: “The removal trays and carousel systems can be used on any primary gyratory crusher – Metso or third party.”

While this was a known and tested concept, this project required a completely new carousel and removal tray design and also new wear parts which included new concave liner design, patterns and trial castings, according to Metso.

Metso’s team of experts completed this project in six months, from customer order until delivery.