Automating mill relining

Online Editor

Roboticisation of proven technologies and improved processes are enabling liner exchange with no one inside the mill and faster relining speeds, explains Elisa Davies.

Mill relining remains the most dangerous maintenance task associated with mineral concentrators, with hazards akin to those in underground mining. Additionally, with increased demand for metals such as copper, minerals processing must be more efficient. Shutdowns have consequences for production when the mill is taken offline. The necessary activity of mill relining is on this critical path, so reducing its duration will deliver economic gains.

Mill relining systems manufacturer Russell Mineral Equipment (RME) believes the solution to reducing risk and reline duration lies in automation. The company’s founder, Dr John Russell, describes this as the ultimate in safety and improved commercial performance for concentrators. “Our goal is to provide the means to reline mills with no-one inside, an environment that allows us to speed up the machines and processes, consistently and repeatably. I’m pleased to say this advanced methodology is now a reality.”

Roboticising proven methods

Dr Peter Rubie, who held the role of chief engineer until 2019, and is RME board non-executive director, played a key role in the development of the company’s automation technologies. He says that, “Mining can be conservative with respect to technology adoption. However, for some of our customers implementing automation, even one hour of mill downtime can cost upwards of US$200,000 in lost production. Roboticising our proven, existing systems minimises implementation risk and delivers the potential to significantly improve mill availability.”

A safer systems approach

Developing these capabilities has been a collaborative undertaking and required a systems-engineering approach. RME understood that to safely automate mill relining, it needed to consider the many interdependent tasks across the entire process.

Industry safety expert and RME’s group project manager, Wayne Herbertson, explains: “When introducing changes to relining on the outside of the mill we also reviewed what was happening inside. For example, introducing robotics that reach higher on the mill exterior, without addressing the inside activities, can increase hazards.”

The result is an advanced, modular and integrated system that automates manual repetitive tasks, eliminates hazards and accelerates relining from outside the mill. The centrepiece remains the industry’s widely used seven-axis mill relining machine (MRM), which can be deployed (or, from 2024 onwards, field-upgraded) with robotics technology. The in-mill technology is complemented by a semi-automated knock-in system on the exterior and a range of innovating tooling.

Now, the roboticised MRM, together with compatible liner and bolt design, can grab knocked-in worn liners off the shell or from the charge, and place new liners against the shell with millimetre precision. This precision enables the securing of liners, nuts and bolts from the mill’s exterior – all with no one inside.

Mine site data is promising

RME is working with several sites progressively automating mill relining. Commercial outcomes for the concentrators are already promising. For example, a 38’ SAG mill has so far secured a 65% reduction in risk exposure inside the mill and a 30% liner replacement speed improvement compared to conventional relining. Performance data is captured using video and analysed by the company’s discrete event simulation technology. This site also observed that, since automating the knock-in process, there’s been no record of a safety injury during this phase of relining.

John Russell anticipates that longer-life mines will favour automated mill relining. “High altitude sites will benefit from improved fatigue management. However, the beauty of this integrated technology ecosystem is that it is modular and future-proofed. Mines of all sizes can deploy the base components and take incremental automation steps at their own pace.”

Elisa Davies is with Russell Mineral Equipment.