Services — Tunnelling

Tunnelling Services

TBM tunnelling, roadheader excavation, drill and blast tunnelling, shaft sinking, and tunnel lining — delivered by teams who have built some of Australia's most complex billion-dollar tunnel infrastructure.

Overview

Tunnelling is where underground mining expertise meets civil infrastructure at its most demanding. The precision, safety discipline, and ground management capabilities required to bore through kilometres of rock beneath cities, rivers, and mountains represent the highest level of underground competence. Jahkai's tunnelling teams have been deployed on multiple billion-dollar Australian tunnel projects — the same projects that are now the benchmark reference for the mega-infrastructure programs being built across the Gulf.

We provide complete tunnelling capability across all excavation methods: TBM (tunnel boring machine) operations, roadheader excavation, conventional drill and blast tunnelling, shaft sinking, and micro-tunnelling. Our teams do not specialise in a single method — we select the right excavation approach for the geology, alignment, cross-section, and programme requirements of each project. This versatility is critical, because most major tunnel projects require multiple methods as ground conditions change along the alignment.

Our track record spans transport tunnels, hydro-electric tunnels, motorway tunnels, and rail tunnels — projects where schedule penalties are measured in millions of dollars per day and where a single mistake in ground management can have catastrophic consequences. The same crews take that discipline to the next tunnel.

What We Deliver

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TBM Tunnelling
Operation of tunnel boring machines for large-diameter tunnel excavation in both hard rock and soft ground conditions. Our TBM crews have operated on projects using Earth Pressure Balance (EPB) machines for soft ground and mixed-face conditions, and open-mode hard rock TBMs for competent rock. We provide experienced crews for TBM operation, segment erection, grout injection, probe drilling, and the critical muck handling and logistics chain that keeps the machine advancing.
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Roadheader Tunnelling
Mechanised excavation using heavy-duty roadheaders for tunnel profiles where TBMs are not suitable — typically non-circular cross-sections, short drives, or variable geology where the flexibility of a roadheader provides better programme outcomes than a fixed-diameter TBM. Our teams operate both transverse-type and axial-type roadheaders, with particular depth of experience on Sandvik MT720 and Mitsui S300/S200 platforms. Roadheaders provide selective excavation, minimal overbreak, and zero-blast vibration.
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Drill & Blast Tunnelling
Conventional drill and blast excavation for tunnels in hard rock where mechanical excavation is not efficient. We design and execute blast rounds for tunnel cross-sections from 20 square metres to over 150 square metres, with smooth-wall and pre-split techniques to minimise overbreak and maintain wall stability. Our blast engineers design patterns that achieve consistent advance while staying within vibration limits — particularly critical for tunnels beneath existing infrastructure or in urban environments.
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Shaft Sinking
Vertical excavation for tunnel access shafts, ventilation shafts, emergency egress shafts, and service shafts. Shaft sinking for tunnel projects typically involves drilling and blasting in confined vertical spaces, with ground support installation in freshly exposed rock that may be under water pressure or in squeezing ground conditions. Our shaft crews are experienced in managing the specific hazards of vertical development including falling objects, water inflow, and restricted ventilation.
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Micro-Tunnelling
Pipe-jacking and micro-tunnelling for utility crossings, drainage systems, and small-diameter service tunnels. These operations are typically conducted from launch shafts using remotely operated micro-TBMs, with real-time steering guided by laser alignment systems. Micro-tunnelling is the preferred method for crossing beneath roads, railways, and waterways where surface disruption is not acceptable.
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Tunnel Lining & Finishing
Precast concrete segment lining installation for TBM tunnels, cast-in-place concrete lining for mined tunnels, shotcrete primary lining, waterproofing membrane installation, and final finishing works. The permanent lining is the most critical structural element of any tunnel — it must resist ground loads, water pressure, and seismic forces for design lives typically exceeding 100 years. Our lining crews understand that quality in lining installation is non-negotiable.

Equipment & Technology

Major tunnel projects deploy some of the largest and most complex equipment in the construction industry. Our teams are experienced across all primary tunnelling equipment platforms.

  • Herrenknecht TBMs — The world's leading TBM manufacturer, producing machines from micro-TBMs through to the largest-diameter hard rock and EPB machines operating globally. Our crews have operated Herrenknecht machines on Australian tunnel projects with diameters up to 15.4 metres
  • Sandvik MT720 roadheader — Heavy-duty transverse-type roadheader with 300kW cutting power, capable of excavating rock up to 120 MPa UCS. Widely deployed on Australian tunnel projects for cavern excavation, cross-passages, and tunnel enlargements
  • Mitsui S300 and S200 roadheaders — Axial-type roadheaders providing excellent profile control and efficient excavation in medium-strength rock. Extensively used in Australian coal mine development and civil tunnel construction
  • Segment erectors and lining systems — Vacuum erectors, ring build equipment, grout injection systems, and segment handling logistics for TBM-driven tunnels
  • Ventilation systems — Primary and secondary ventilation fans, ducting systems, air quality monitoring, and ventilation management for tunnel environments where fresh air supply is the first constraint on productivity and safety
  • Muck handling systems — Continuous conveyors, muck cars, rolling stock, and the complete materials logistics chain that removes excavated material from the face and delivers construction materials to the working area
  • Probe drilling and grouting equipment — Advance probe drilling rigs for ground investigation ahead of the face, and grouting equipment for ground treatment in zones of weakness or water inflow
  • Survey and guidance systems — Automated machine guidance, real-time TBM position monitoring, convergence monitoring arrays, and the survey infrastructure that ensures the tunnel arrives at its target within specification

Local employment and training

We employ people from the place the mine is, and we train them on the tools, in the mine, from offsider through operator to supervisor. We leave a trainer behind.

Training & Knowledge Transfer

Tunnelling demands a workforce with skills ranging from heavy equipment operation to precision engineering. We build that workforce on the tools, in the tunnel, across the tunnelling disciplines, and we leave a trainer behind.

  • TBM operations — Machine operation, segment erection, annular grouting, probe drilling, face pressure management, and the real-time decision-making required when ground conditions change unexpectedly mid-drive
  • Roadheader operations — Cutting sequence management, profile control, cutter head maintenance, mucking coordination, and the ground assessment skills needed to identify changing conditions from the operator's seat
  • Tunnel drill and blast — Face drilling, blast design interpretation, charging, firing, muck-out coordination, and the controlled blasting techniques specific to tunnel construction
  • Ground support in tunnels — Rock bolt and cable bolt installation, lattice girder erection, shotcrete application, and the ground condition assessment that determines what support is required and when
  • Concrete segment handling and erection — Segment logistics, ring build procedures, waterproofing gasket management, and quality control for the permanent tunnel lining
  • Tunnel survey and alignment — Tunnel control networks, TBM guidance systems, convergence monitoring, and the survey discipline that ensures the tunnel arrives at its destination within millimetre tolerance
  • Tunnel ventilation management — Fan operation, air quality monitoring, dust and gas management, and the ventilation calculations required to maintain safe working environments in long tunnel drives
  • Tunnelling supervision and coordination — Shift management, production planning, resource allocation, interface management with other disciplines, and the communication protocols that keep complex tunnel operations running safely and on schedule

Tunnelling competency is built over years, not weeks. Our training programs are multi-year pathways that take local crew from entry-level roles through to qualified tunnellers and, ultimately, tunnel supervisors and engineers. We embed trainees into active tunnel crews on real projects — because there is no substitute for learning tunnelling inside an actual tunnel.

Ready to discuss your tunnelling requirements?

From TBM operations to roadheader excavation, drill and blast tunnelling to shaft sinking — Jahkai brings proven tunnel capability from Australia's most demanding projects.

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