Reline your thinking (3/4): Virtual reality operator training

Training reline machine operators is difficult due to the uniqueness of the task and equipment involved. The unfortunate reality is that operators rarely get the opportunity to refine their skills and the few opportunities that do arise are under conditions that are far from ideal. This creates a high demand for the handful of highly experienced operators, making availability a serious concern and succession planning practically impossible.

Over the years, multiple attempts have been made to address the lack of quality operator training options. However, by reviewing these approaches it becomes apparent that all have significant compromises and fail to address the issue. Considering these findings, a comprehensive solution is urgently required and thanks to recent developments in virtual reality technology, that solution has finally arrived.

Dedicated training facility

Perhaps the most obvious solution to training operators on any piece of equipment is to provide a dedicated training area in which they can learn safely and make mistakes without consequence. A handful of sites have invested in such a solution and have no doubt benefitted massively from improved operator skill. However, for most sites, access to such a facility is not feasible due to space or budget constraints.

Mill reline machines are expensive, large and difficult to move over any significant distance. Traditionally this has meant that once a mill reline machine is placed on a mill deck, it stays there for the duration of its life. Mill decks are extremely optimized in plant layout planning, resulting in a deck so compact that even moving the reline machine from the storage location to the working location can prove difficult. A dedicated space for operator training is a luxury that is cut from typical plant design long before the first layout drawing is completed.

On-the-job training

The lack of a dedicated training facility means that most sites are limited to operating the reline machine only when it is installed inside the mill. This means that training can occur exclusively during a mill shutdown, which is generally the most time critical activity during any site maintenance. Operators are therefore trained ‘on-the-job’, learning the controls and the behaviours of the machine while participating in an active reline.

An unfamiliar operator learning to control a powerful reline machine inside a confined space surrounded by support personnel is a hazard that would be completely unacceptable in any other context. However, most sites are left with no choice, and train their operators under shift conditions in a hot, dark, loud environment with all the time pressure that comes with performing a critical path maintenance task.

Waiting for automation

A final option that some sites are tempted to adopt is to wait for the rise of automation. The thought is that mill relining technology will progress to a point where personnel are no longer required to work inside the mill and machine operation is mostly automated, requiring little input from operators.

Unfortunately, that future is still far off and will likely never be achieved by most sites currently in operation. It is therefore critical that automation is not seen as a future silver bullet that justifies the continuation of poor training practices.

What is needed?

Many aspects of relining a grinding mill can be practiced without access to a mill reline machine. Rigging, dogging and bolting are all tasks with readily available training environments. Clearly it is the operation of the reline machine that is most difficult to accommodate. So, what are the minimum requirements to provide a quality reline machine training environment?

Here are the essential features for a reline machine training tool:

• Access to accurate physical machine controls
• An operable machine that accurately responds to controls
• An operable machine with all behavioural logic, e.g. Interlocks, operator assistance features
• Interaction with liner pieces (alternative loads are not effective for training)
• An environment that accommodates the accurate pick up and placement of liners

The virtual reality breakthrough

Until recently, there was only one possible solution to providing a reline machine training environment that met the above requirements – a physical reline machine manipulating liners inside a full or partial mill.

However, computer simulation has been capable of meeting nearly all these demands for over a decade. Physics-based simulation can accurately replicate the behaviour of a mill reline machine model in a mill while handling liner pieces. The lacking feature has always been the simulation ‘environment’. While a 2D monitor can provide a visual window into the simulation, the lack of depth perception and peripheral awareness has made such simulators not only difficult to operate, but also poor representations of the real-world task.

This is where virtual reality has made a training breakthrough possible. Thanks to stereo vision and high-precision head tracking, virtual reality gives the operator a sense of immersion that is a genuine substitution for real-world training. VR depth perception enables liner interaction with a precision that can only be truly appreciated by experiencing the technology in person.

A practical training solution

Metso Outotec has leveraged the power of virtual reality to create a training simulator for mill reline machine operators. The simulator allows operators to control machines from our standardized product range, ensuring that the developed skills are directly applicable to any site with a Metso Outotec mill reline machine.

The simulator is also compact, inexpensive and easy to transport, consisting of a laptop, VR headset, reline machine remote control and interface box. The simple system can be packed into a single transport case and sent to any site to train local operators.

The skills developed by operators as they practice picking up and placing a full range of liners inside a typical grinding mill are of great benefit. The muscle memory and machine knowledge achieved through extensive training helps operators to reline with more efficiency while maintaining a greater awareness of their surroundings, improving safety.

Of course, machine control is only one aspect of any mill relining task. Metso Outotec also offers a wide range of practical training solutions and services. For more information please contact your local Metso Outotec account manager.

This blog is part of a series. Did you miss them? Make sure to go back and read the full series!

1.) Appropriate and safe mill access

2.) Incremental automation for mill relining