Tunnel Ground Support (Bolting/Mesh/Shotcrete) SWMS

Tunnel ground support installs and maintains the support system that keeps a tunnel stable — rock bolts, mesh, steel sets, lattice girders, shotcrete and segmental linings — applied to the excavated ground to prevent falls of ground and control deformation. It is the control that makes underground work survivable, but installing it requires working at or near the freshly exposed face and crown, sometimes under ground that is not yet supported, with the plant and processes used to place the support. The hazards are the fall of ground onto workers before or during support installation, the high-pressure shotcrete and the respirable crystalline silica it generates, working at height to the crown, the support-installation plant, and the underground atmosphere and diesel particulate. This document is written on the basis that ground support is installed to a support design in a controlled sequence and method that keeps workers out from under unsupported ground, and that the shotcrete and silica hazards are controlled.

Tunnel ground support engages several high risk construction work categories under the model Work Health and Safety Regulations — work involving a tunnel, work in or near a confined space, work in a contaminated or flammable atmosphere, and where access to the crown is at height, a risk of a person falling more than 2 metres — so a safe work method statement is required before the work commences, kept readily accessible, and given to the principal contractor if one is appointed. Spraying shotcrete is high-risk processing of a crystalline silica substance, so the silica controls apply, and diesel particulate from plant is controlled against its standard. This document coordinates the support-sequence, fall-of-ground, shotcrete-silica, working-at-height and atmosphere controls so the tunnel is supported without exposing workers to unsupported ground.

Hazards identified

9 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Engineering: install ground support to a support design by a competent person in a controlled sequence and method — mechanised or remote installation and scaling — so workers are not positioned under unsupported ground, with the support type and density matched to the ground.
2. 2Engineering: scale down loose ground before workers approach, and use temporary or initial support to make the ground safe before further work, so the face and crown are controlled progressively.
3. 3Engineering: control respirable crystalline silica from the shotcrete — wet-mix spraying, dust suppression and capture, and ventilation of the spraying area — monitored against the respirable crystalline silica workplace exposure standard of 0.05 mg/m3 (eight-hour TWA), reframed as a workplace exposure limit from 1 December 2026.
4. 4Engineering: manage the high-pressure shotcrete spray and rebound — nozzle and line controls, exclusion of non-essential workers, and inspection of high-pressure lines.
5. 5Engineering: safe access and fall-prevention for installing crown and high-sidewall support — work platforms and elevating work platforms — rather than improvised access at height.
6. 6Engineering: forced underground ventilation designed to dilute and remove respirable crystalline silica, diesel particulate, dust and other contaminants and maintain a safe atmosphere, with continuous atmospheric monitoring.
7. 7Engineering: low-emission or filtered underground plant and ventilation to control diesel particulate matter, monitored against the diesel particulate matter exposure standard, currently 0.1 mg/m3 (eight-hour TWA, sub-micron elemental carbon), with a Workplace Exposure Limit of 0.01 mg/m3 (respirable elemental carbon) from 1 December 2026.
8. 8Administrative: prepare a SWMS before the work for the tunnel and confined space high risk construction work, apply the confined space entry and atmospheric controls and permits, and where the work is high-risk processing of a crystalline silica substance, a silica risk control plan with air and health monitoring.
9. 9Administrative: air monitoring for respirable crystalline silica against the respirable crystalline silica workplace exposure standard of 0.05 mg/m3 (eight-hour TWA), reframed as a workplace exposure limit from 1 December 2026, and for diesel particulate, dust and gases, with health monitoring for workers carrying out high-risk silica work and records retained.
10. 10Administrative: a documented underground emergency response and rescue capability — refuge, self-rescuers where required, communication and rescue arrangements — briefed to all workers.
11. 11Administrative: all workers must hold a valid White Card (General Construction Induction Training, CPCCWHS1001) before entering any construction workplace, with underground, confined space and tunnelling competencies verified as applicable.
12. 12Administrative: conduct a pre-shift toolbox talk covering the day's work, ground and atmospheric conditions, the controls, plant movements, required PPE and emergency and rescue procedures, and record attendance in the consultation section.
13. 13Administrative: consult workers and health and safety representatives on the work and its risks, record the consultation, and keep this document available at the workplace.
14. 14PPE: underground high-visibility clothing, head protection, eye protection to AS/NZS 1337.1, hearing protection matched to the measured noise, gloves, and Class I or Class II safety footwear with protective toecap to AS/NZS 2210.3.
15. 15Administrative: review and update this SWMS whenever the work, the ground or atmospheric conditions, the plant or the controls change, after any incident or near miss, when a worker or health and safety representative raises a concern, or at minimum every 12 months.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

A tunnelling crew is installing ground support — rock bolts, mesh, steel sets and shotcrete — to stabilise a tunnel as it advances. Because the work involves a tunnel, a confined and potentially contaminated atmosphere, and access to the crown at height, and spraying shotcrete is high-risk silica processing, a SWMS is prepared and a silica risk control plan is in place. The support is installed to a support design by a competent person in a controlled sequence with mechanised installation and scaling, so workers are not positioned under unsupported ground, with the support type and density matched to the ground. Loose ground is scaled down before workers approach, and temporary or initial support makes the ground safe before further work, controlling the face and crown progressively. Respirable crystalline silica from the shotcrete is controlled with wet-mix spraying, dust suppression and capture, and ventilation, and the high-pressure spray and rebound are managed with nozzle and line controls and exclusion of non-essential workers. Crown and high-sidewall support is installed from work platforms with fall-prevention rather than improvised access. Forced ventilation dilutes and removes silica, dust and diesel particulate, and air monitoring tracks silica and diesel particulate with health monitoring for exposed workers. A rescue capability is in place, and the SWMS and records are retained.

Related legislation

• Model Work Health and Safety Act — primary duty of care; the duty to consult workers; the reckless-conduct offence; and notifiable-incident provisions, as enacted in each jurisdiction.
• Model Work Health and Safety Regulations — Section 291 high risk construction work and the SWMS preparation and review duties, the confined space provisions, and where relevant the crystalline silica high-risk processing, silica risk control plan, air monitoring and health monitoring provisions, as enacted in each jurisdiction.
• Model Codes of Practice — Tunnelling work; Excavation work; Confined spaces; and Managing risks of respirable crystalline silica in the workplace (2025).
• Where blasting is used, the explosives legislation governs the licensing and authorisation of shotfirers and the storage, transport and security of explosives; and the diesel particulate matter exposure standard, currently 0.1 mg/m3 (sub-micron elemental carbon) with a Workplace Exposure Limit of 0.01 mg/m3 (respirable elemental carbon) from 1 December 2026, applies underground.
• Victoria operates under the Occupational Health and Safety Act 2004 and the Occupational Health and Safety Regulations 2017, with the high risk construction work, tunnelling and confined space provisions applying in place of the model instruments.

Frequently asked questions