WRAC explained: the risk assessment behind most Queensland mine-site changes

WRAC stands for Workplace Risk Assessment and Control. It is a broad-brush, team-based risk assessment method that has become the default tool on Queensland mine sites for assessing changes to plant, process and equipment. If you are bringing anything new onto a site, expect to be asked for one.

Where the requirement comes from

Queensland's mining safety legislation (the Coal Mining Safety and Health Act 1999 and the Mining and Quarrying Safety and Health Act 1999) puts an obligation on the site senior executive to ensure that risk to people is at an acceptable level, and requires a safety and health management system with a risk management process at its core. The legislation does not prescribe WRAC by name. It has become the standard tool because it is quick to run, it produces a ranked list of controls, and regulators and auditors recognise it.

Typical triggers on the sites we work on:

• New or modified fixed plant, mobile equipment or attachments.
• A change in how a task is done, for example moving from manual to mechanically assisted handling.
• New technology the site has not operated before.
• Construction and commissioning activities inside an operating plant.

Where WRAC sits among the other tools

WRAC is not the only risk method and it is not the right one for everything.

• A JSA or JHA covers the steps of a single task. It is narrower than a WRAC.
• A HAZOP works through a process line by line using guidewords. It is deeper and slower, and suited to process plant.
• A bow-tie maps the controls on either side of a single major unwanted event.
• An FMEA looks at how individual components fail.

WRAC sits between the JSA and the HAZOP: broad enough to cover a whole system or change, structured enough to rank the risks and assign controls.

How a WRAC session runs

1. Define the scope. What is being assessed, where it starts and stops, and what is excluded. A vague scope is the most common cause of a weak WRAC.
2. Assemble the team. The people who operate and maintain the equipment, a supervisor, a safety representative and the engineer responsible for the design. A facilitator keeps the session on track and should not be the designer.
3. Break the system into steps or nodes. For a piece of plant, that might be install, operate, clean, maintain and remove. For a process, each stage.
4. For each step, identify unwanted events. What could go wrong: contact with moving parts, dropped loads, stored energy release, manual handling injury, fire.
5. List existing controls and rate the consequence and likelihood using the site's risk matrix to get a risk rank.
6. Propose additional controls where the rank is not acceptable, working down the hierarchy: eliminate, substitute, isolate or engineer out, then administrative controls, then PPE.
7. Assign an owner and a date to every action, and rate the residual risk once the control is in place.
8. Sign off and track. The WRAC is not finished when the meeting ends. It is finished when the actions are closed, which usually has to happen before commissioning.

What the engineer brings to the room

A WRAC run without an engineer produces administrative controls: signage, procedures, training. Those are the weakest rungs on the hierarchy. The engineer's job in the session is to turn hazards into engineering controls and to make sure the controls are real.

• Bring the drawings, the loads and the energy sources, so the team is assessing the actual design rather than a description of it.
• Quantify where it matters. "The gantry is heavy" is a hazard. "The gantry section is 1.2 tonnes and the current lifting method has no rated attachment point" is a control gap.
• Propose design changes in the room. Guarding, interlocks, rated lifting points, mechanical handling aids, isolation points, access platforms to AS 1657. Many of these are cheap during design and expensive after fabrication.
• Take the actions back into the design, then verify on site that what was built matches what the WRAC assumed.

Getting value rather than paperwork

A few habits separate a WRAC that changes the outcome from one that just produces a spreadsheet.

Do it early enough to change the design. A WRAC held a week before commissioning can only add procedures. Held at concept or preliminary design, it can change the equipment.

Resist rating everything "unlikely". Teams under time pressure drift toward the bottom of the matrix. Ask for the evidence behind a likelihood rating, and record it.

Record the assumptions. If the risk rank depends on an operating limit or a maintenance interval, write it down. Those assumptions become design requirements and, later, inspection criteria.

Close the loop. Every engineering control that comes out of a WRAC should appear on a drawing, in a specification or in a commissioning check. If it does not, it did not happen.