Alert no. 401 | 10 November 2021 | Version 1

Pressurised steering accumulators sent off-site

What happened?

Two accumulators from the steering system of a Komatsu 830E rear dump truck were sent from a mine to the OEM for servicing. Through their own procedures, the OEM discovered that they were still pressurised. There wasn’t any notification or tagging to warn about remaining pressure.

How did it happen?

The mine’s procedures require accumulators to be:

• de-pressurised before sending them off-site for most occasions.
• clearly marked to indicate remaining pressure in the event that they cannot be de-pressurised before being sent off-site.

The mine’s procedures weren’t followed.

Key issues

• A large amount of energy is contained in compressed gas. The unexpected release of this energy is hazardous and has caused safety incidents in the past.
• The mine relied on an administrative procedure to ensure the safety of persons working with the accumulators.

Recommendations

• Release pressure before sending components offsite (where possible).
• If feasible, higher order controls (e.g. engineering vs administrative) should be developed to ensure the removal of compressed gas.
• Clearly tag all pressure components being sent offsite (including for depressurised items) to ensure that recipients are aware of their status.

References and further information

• Significant Incident Report 268; Department of Mines, Industry Regulation and Safety; WA
• Safety Alert SA 15-07; Department of Industry, Resources and Energy; NSW
• Safety Bulletin 67 - Managing high pressure fluids and gases; RSHQ
• Safety Bulletin 70 – Hazards of stored energy; RSHQ
• Safety Bulletin 49 – Isolation of plant containing stored energy; RSHQ
• Coroner’s report – Inquest into fatality; Exploding nitrogen track tensioning cylinder
• Recognised Standard 23 - Fluid Power Safety in Coal Mines; RSHQ