NATM / Sprayed Concrete Lining Tunnelling SWMS
New Austrian Tunnelling Method and SCL — sequential excavation with primary support and shotcrete lining. Soft-ground face stability, settlement monitoring, alkaline rebound from shotcrete.
SWMS variants reference your state’s WHS legislation. Instant download after payment.
NATM and SCL tunnelling — the New Austrian Tunnelling Method and sprayed concrete lining — excavate a tunnel in a sequence of partial-face headings, supporting the ground immediately with sprayed concrete (shotcrete), rock bolts and other support, and relying on the ground itself, mobilised and supported, to help carry the load. It is a flexible method for variable ground, but the immediate support of freshly exposed ground is the defining safety challenge: workers and the support spray operate close to ground that has just been excavated and is not yet fully supported, and the method depends on the excavation and support sequence being followed and the ground behaviour monitored. The shotcrete process also generates high respirable crystalline silica, and the work carries the usual underground hazards of atmosphere, egress and diesel particulate. This document is written on the basis that NATM and SCL tunnelling is carried out to a defined excavation-and-support sequence with continuous monitoring of ground behaviour, and that the shotcrete silica is controlled.
NATM and SCL tunnelling 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, and work in a contaminated or flammable atmosphere — 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 tunnel plant is controlled against its standard. This document coordinates the excavation-sequence, immediate-support, monitoring, shotcrete-silica, ventilation and atmosphere controls so the tunnel is advanced without a ground failure or uncontrolled silica exposure.
Hazards identified
9 hazards covered, sorted by priority.
Rock fall and collapse onto workers at the heading before support is complete
Loss of ground control where the sequence or support timing is not followed
Silicosis and respiratory disease from the high-silica shotcrete process
Impact and eye injury from the spray nozzle and rebounding concrete
Fatal crushing of workers from unsupported or failing ground
Carcinogenic diesel exhaust exposure compounding the dust burden underground
Asphyxiation, poisoning or explosion in the confined underground atmosphere
Skin and eye burns and respiratory irritation from alkaline accelerators
Delayed escape and entrapment if conditions deteriorate underground
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1Engineering: excavate and support in a defined sequence of partial-face headings designed by a competent person for the ground, with the immediate sprayed-concrete and rock-bolt support installed to the support plan before workers are exposed to unsupported ground for longer than the sequence allows.
- 2Engineering: continuous monitoring of ground behaviour — convergence, deformation and instrumentation — with trigger-action responses so the sequence and support are adjusted to the observed ground.
- 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.
- 4Engineering: 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.
- 5Engineering: manage the high-pressure shotcrete spray and rebound — nozzle and line controls, exclusion of non-essential workers from the spray zone, and inspection of high-pressure lines.
- 6Engineering: 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.
- 7Administrative: manage shotcrete accelerators and admixtures to their safety data sheets with skin, eye and respiratory protection.
- 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.
- 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.
- 10Administrative: a documented underground emergency response and rescue capability — refuge, self-rescuers where required, communication and rescue arrangements — briefed to all workers.
- 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.
- 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.
- 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.
- 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.
- 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
The national model code for tunnelling work, covering ground control, atmosphere, ventilation, emergency and the management of underground hazards.
Excavation, shaft and ground-support controls for the excavated openings and access shafts of the tunnelling work.
Atmospheric testing, ventilation, entry permit and rescue controls for the confined underground workings, shafts and chambers.
The risk assessment, silica risk control plan, air monitoring and health monitoring duties where the work generates respirable crystalline silica.
Selection, fit testing and use of P2, powered and supplied-air respiratory protection for the silica, dust, diesel particulate and atmospheric hazards of the underground work.
High-Risk Construction Work triggered
Excavating a tunnel by NATM or SCL is work involving a tunnel, which is high risk construction work requiring a SWMS before the work commences.
The underground heading, which may be oxygen-affected or have a contaminated atmosphere, brings the work within the confined space category and its controls.
The underground atmosphere, with dust, shotcrete rebound and diesel particulate, may be contaminated, bringing the work within this category and driving the ventilation controls.
This is tunnelling work, which engages the high risk construction work categories above under the model WHS Regulations, so a SWMS must be prepared before the work commences, kept readily accessible, reviewed as necessary, and given to the principal contractor if one is appointed. Tunnelling is carried out to the model Tunnelling work Code of Practice and a rigorous regime of ground control, ventilation and emergency preparedness, and the confined space, excavation and, where relevant, explosives controls apply. Where the work generates respirable crystalline silica, the silica risk control plan, air monitoring and health monitoring duties apply, with the exposure standard reframed as a workplace exposure limit from 1 December 2026. An incident in a tunnel can trap and kill workers with limited means of escape, and breaches of the primary duty of care under the model WHS Act are actively enforced, with offence categories running from failure-to-comply through to reckless conduct, and the most serious breaches carrying imprisonment for individuals. Body-corporate maxima are substantial and indexed; the current maximum follows the prevailing schedule of the responsible regulator.
Who this is for
- →NATM and SCL tunnelling crews excavating and supporting the heading.
- →Shotcrete sprayers and pump operators in the tunnel.
- →Rock-bolting and ground-support crews at the face.
- →Tunnelling and geotechnical engineers managing the sequence and monitoring.
- →Project managers and supervisors overseeing the tunnel SWMS and the silica risk control plan.
What you receive
- ✓Editable Microsoft Word document (.docx) fully compatible with Microsoft Word 2016 and newer, Google Docs, and LibreOffice Writer.
- ✓Title page with editable fields for PCBU name, ABN, site address, project name, principal contractor details, and document revision date.
- ✓Hazard register with the natm scl tunnelling hazards — each with a documented consequence, inherent risk rating on a 5x5 likelihood-consequence matrix, hierarchy-of-control measures, and residual risk rating.
- ✓Excavation-and-support sequence prompts, a ground-behaviour monitoring and trigger-action section, a shotcrete silica and rebound control section, and a silica risk control plan aligned to the model crystalline silica Code of Practice.
- ✓Confined space entry, atmospheric-monitoring and underground emergency and rescue prompts, and a silica risk control plan aligned to the model crystalline silica Code of Practice referencing the 0.05 mg/m3 exposure standard.
- ✓Competency, ticket and induction verification fields, and a respiratory protection selection and fit-test record per AS/NZS 1715.
- ✓Worker consultation record per the model WHS Act consultation duty and a worker sign-on register (blank, expandable).
- ✓Applicable legislation and Codes of Practice schedule pre-populated for the model WHS jurisdiction with a state-variance reference table covering the harmonised states, plus Victoria.
- ✓Emergency procedure template and a revision log.
Worked example
A tunnelling crew is advancing a tunnel by NATM and sprayed concrete lining, excavating in a sequence of partial-face headings and supporting the ground immediately with shotcrete and rock bolts. Because the work involves a tunnel, a confined and potentially contaminated atmosphere, and spraying shotcrete is high-risk silica processing, a SWMS is prepared and a silica risk control plan is in place. The excavation and support sequence is designed by a competent person for the ground, and the immediate sprayed-concrete and rock-bolt support is installed to the support plan so workers are not exposed to unsupported ground for longer than the sequence allows. Ground behaviour is monitored continuously — convergence, deformation and instrumentation — with trigger-action responses adjusting the sequence and support to the observed ground. Respirable crystalline silica from the shotcrete is controlled with wet-mix spraying, dust suppression and capture, and ventilation of the spraying area, and forced ventilation dilutes and removes dust, silica and diesel particulate. The high-pressure spray and rebound are managed with nozzle and line controls and exclusion of non-essential workers, and accelerators are managed to their safety data sheets. Air monitoring tracks silica and diesel particulate, with health monitoring for exposed workers, and a rescue capability is in place. The SWMS, monitoring and silica 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
What is NATM or SCL tunnelling?
NATM, the New Austrian Tunnelling Method, and SCL, sprayed concrete lining, excavate a tunnel in a sequence of partial-face headings and support the ground immediately with sprayed concrete, rock bolts and other support, relying on the ground itself, mobilised and supported, to help carry the load. The immediate support of freshly exposed ground and the monitoring of ground behaviour are central to the method.
Why is the excavation-and-support sequence so important?
The method depends on excavating and supporting in a defined sequence designed for the ground, with the immediate support installed before workers are exposed to unsupported ground for longer than the sequence allows. Departing from the sequence or the support timing can lead to loss of ground control and collapse, so the sequence is engineered and the ground behaviour is monitored with trigger-action responses.
Is the shotcrete a silica hazard?
Yes. Spraying shotcrete is high-risk processing of a crystalline silica substance because the cement and aggregate liberate respirable crystalline silica, and in the confined heading the dust can accumulate. A silica risk control plan is prepared, wet-mix spraying, dust suppression and ventilation control the silica, and air monitoring against the 0.05 mg/m3 standard with health monitoring for exposed workers applies.
How is ground behaviour monitored?
Through continuous monitoring of convergence, deformation and instrumentation as the heading advances, with trigger-action responses so the excavation sequence and the support are adjusted to the observed ground. The method relies on the observed behaviour of the ground informing the support, so monitoring is integral rather than a check after the fact.
What categories apply to NATM and SCL tunnelling?
It engages the tunnel, confined space and contaminated-atmosphere high risk construction work categories, so a SWMS is required before the work begins, and because shotcreting is high-risk silica processing a silica risk control plan also applies, with air and health monitoring, alongside the ground-support and ventilation controls.