NSW tunnel and shaft work: safety decisions start before excavation
Underground work depends on more than the skill of the person operating a machine. Design decisions, contractor coordination, changing ground conditions, reliable communications and emergency arrangements all affect whether people can work safely.
SafeWork NSW's Tunnels and shafts in construction Code of practice, August 2026, commenced on 28 August 2026 and replaced the 2006 code. It covers planning, design, construction, installation and commissioning, as well as tunnel maintenance, repair and renovation. It does not apply to mines and quarries intended to extract minerals, which have separate legislation.
The client still has a role
Appointing a specialist contractor is not the end of the commissioning organisation's involvement. The code addresses responsibilities throughout procurement and the project lifecycle. Businesses with overlapping duties need to consult, cooperate and coordinate. A contract cannot simply transfer away a statutory WHS duty.
For a public-sector asset manager or community organisation commissioning relevant work, the practical question is not merely, “Has the contractor supplied a safety folder?” It is, “Have the right people assessed this project, and how will we know the controls work?”
Six questions for a project discussion
1. What has been designed out? Ask how the design and construction options were compared before people were committed to working underground.
2. Who owns each interface? Identify the people responsible for coordination between designers, contractors, plant suppliers and operational staff. Make unresolved issues visible.
3. What changes trigger a review? New ground conditions, altered equipment or a different work sequence should not become an informal workaround.
4. How are workers heard? Include affected workers and their health and safety representatives in consultation. Explain the outcome, not just the decision.
5. What evidence shows controls are effective? Ask for competent verification, maintenance and monitoring, rather than accepting that equipment is safe because it is present.
6. Does the emergency plan still fit today's workplace? A plan needs to keep up with progress, changing access routes and the number and location of people underground.
These are original governance questions, not instructions for excavating, supporting, entering or rescuing someone from a tunnel.
A permit is not an engineering redesign
The code explains the Permit to Tunnel process as a way of managing excavation safety and checking performance against the design. It does not replace the certified design or authorise improvised design changes. When conditions fall outside the design assumptions, the response needs to follow the planned controls and formal change process, with competent assessment.
This distinction matters well beyond engineering terminology: paperwork should connect decisions to evidence and authority, not conceal a gap between them.
Protect long-term health as well as immediate safety
The code addresses silica dust, diesel emissions, other airborne contaminants, noise, vibration, heat, skin health, fatigue and psychosocial hazards. A dramatic incident is not the only way someone can be harmed.
Air monitoring and health monitoring serve different purposes. Neither replaces the need to eliminate or minimise exposure. Workers should be able to understand relevant monitoring information, how concerns are escalated and what happens when a control fails. Individual medical information also requires appropriate confidentiality.
For worker representatives, a useful discussion is whether the proposed controls remain effective during maintenance, cleaning, shift changes and other less visible parts of the job, not only during normal production.
Emergency arrangements need to be tested
The code addresses underground communications, accounting for people, escape routes, rescue capability, refuges where relevant, and coordination with emergency services. Equipment alone does not demonstrate readiness. Training and realistic exercises help establish whether the arrangements work for the actual people and conditions.
Do not enter an unsafe underground area or attempt an improvised rescue. Follow the site's emergency arrangements and seek emergency assistance.
Current requirements and the official code
This edition expressly refers to the NSW WHS Regulation 2025 and section 26A of the WHS Act. The approved-code duty requires compliance with the applicable code or another method providing an equivalent or higher standard. SafeWork NSW code directory.
The code also flags the transition from Workplace Exposure Standards to Workplace Exposure Limits on 1 December 2026. Technical exposure assessments should use the requirements applicable at the time, with competent advice, rather than values copied into a blog. NSW Government silica updates.
Source: State of New South Wales (SafeWork NSW), August 2026. This is an original plain-language discussion, not an altered copy of the code. The official document is linked because it includes third-party material excluded from its general Creative Commons licence. This article is general information, not legal or engineering advice, a project safety assessment or an operational procedure.
Checked 13 November 2026.
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