Tunnelling remains a critical component of modern infrastructure, supporting everything from resource extraction and transportation to hydropower production and utility networks. As demand for these underground solutions grows, so does the need for innovative technologies that address the inherent challenges of tunnelling, such as geological uncertainty, high costs, environmental impact, and safety concerns. Several recent developments highlight the industry’s push towards greater efficiency, precision, and sustainability.
Diamond-enabled tunnelling
Element Six (E6), a company specialising in polycrystalline diamond (PCD) and ultra-hard materials, has partnered with Master Drilling, a leader in drilling and mechanised rock excavation. Together, they aim to transform tunnelling through a new synthetic diamond-enabled solution.
According to Koos Jordaan, Executive Director of Master Drilling: “Achieving high quality, nonexplosive tunnel construction with various aspects of value generated compared to traditional rock excavation methods is a key global challenge for tunnel builders – a challenge that Master Drilling and Element Six are uniquely positioned to address.” The partnership leverages Element Six’s patented PCD cutting technology with Master Drilling’s mechanised services. The result is a tunnelling solution that reduces waste rock generation by more than 17% compared to traditional methods.
The technology has undergone testing in both underground and surface environments in the UK and South Africa, involving end-users from the mining and infrastructure sectors. Results indicate “general higher performance compared to traditional rock excavation methods.”
Siobhán Duffy, CEO of Element Six, stated: “This strategic partnership with Master Drilling is another example of the role Element Six plays in De Beers Group’s Origins strategy. Synthetic diamond innovation holds immense potential to shape the future of industrial applications. By extracting a lower amount of rock during tunnel development, the solution we developed in partnership with Master Drilling will significantly reduce waste and environmental impact, ensuring a better tomorrow for generations to come.”
The applications for this technology span multiple sectors. In mining, tunnels provide access to mineral resources and facilitate transportation and ventilation. For transportation, they create shorter routes through challenging terrain or urban areas. In construction, tunnels house utilities, while in the energy sector, they support hydroelectric plants and pipelines.
Trenchless technology for grid expansion
Addressing the growing need for grid expansion, particularly in Germany, Herrenknecht has developed the E-Power Pipe method for trenchless installation of protective pipes. This technology is designed to minimize disruption and environmental impact when laying underground cables across obstacles like existing infrastructure, rivers, and protected areas.
Heitkamp Construction Swiss GmbH received an E-Power Pipe machine in December and will deploy it in grid expansion projects such as SuedLink. The E-Power Pipe enables the installation of cable protection pipes quickly and safely over distances exceeding one kilometer without the need for open trenches.
Around 4,500 crossings will be required for upcoming network expansion projects in Germany alone. Trenchless technologies are essential for overcoming geographical obstacles such as rivers, swamps and wetlands, for protecting nature reserves and recreational areas, groundwater zones, the landscape and valuable agricultural land, or for passing under transport infrastructure, supply and disposal lines or buildings. Herrenknecht offers a range of tunnelling, drilling and laying technologies for this purpose.
The E-Power Pipe method integrates aspects of horizontal directional drilling (HDD) and pipe jacking (microtunnelling). The centerpiece of the system is the fully remote-controlled AVNS350XB jacking machine, designed for lengths exceeding 1,000 meters with a drilling diameter of 505mm. This machine can precisely follow the planned route, navigating under existing infrastructure such as pipelines, roads, railways, or bodies of water. Multiple lines can be laid in parallel with minimal spacing (1–2m).
The AVNS350XB features a jet pump and an integrated hydraulic unit. The jet pump removes excavated material, which allows for jacking distances up to 10 times longer at high speeds in the small diameter range.
The E-Power Pipe installation process involves a thrust unit at the starting point, which pushes the jacking pipes and machine along the predetermined path. The borehole is mechanically supported by the machine and jacking pipes. After breakthrough at the target point, the jacking machine is disconnected, and the prefabricated cable protection pipe is connected to the jacking pipes. The thrust unit then pulls the cable protection pipe back through the borehole, completing the installation. Specialized companies can then pull the underground cables into the protection pipes.
Philipp Kohlschreiber, CEO of HEITKAMP Construction Swiss GmbH, said: “The planned bores must be very precise, with some very low and some very high overburden. The longest planned route is about 1,600 meters long and under difficult conditions. Herrenknecht is currently the only provider of a suitable technology with E-Power Pipe and is the undisputed market leader in the field of underground drilling technology with extensive expertise.”
Maximilian Bischoff, Product Manager E-Power Pipe at Herrenknecht, explained: “E-Power Pipe combines the advantages of microtunnelling and HDD, thus complementing our product portfolio. In the context of current grid expansion projects, we are seeing increased interest in this innovative technology, which has already proven itself in various projects. E-Power Pipe can particularly demonstrate its strengths in long sections, near-surface bore profiles and narrow pipe corridors.”
Heitkamp Construction Swiss, through its new subsidiary Heitkamp Energy Infra GmbH, will begin laying cable protection pipes for the SuedLink
extra-high voltage direct current transmission line in April 2025.
Specialized excavators for underground construction
Liebherr-France SAS has developed the R 930 Tunnel crawler excavator, designed specifically for the challenges of underground construction sites. This machine replaces the R 924 Compact Tunnel and complements the R 950 Tunnel in Liebherr’s range of excavators dedicated to tunnel applications.
The R 930 Tunnel is engineered to operate in tight spaces with difficult access, common in underground construction. Its attachment, available in two lengths, features a swivelling bearing that can reach 2 x 45° angles, enabling it to follow the excavation profile. The machine’s short slewing radius and protected LED headlights reduce the risk of collisions. Cylinders and hoses are positioned for maximum protection, and the machine features steel bodywork for robustness. The R 930 Tunnel can also be equipped with the Liebherr quick coupling system for easy tool changes.
The R 930 Tunnel can be equipped with a Liebherr two- or three-tooth ripper bucket. It can also use a cutter or hammer to cover a broad area of applications. The R 930 Tunnel’s grading blade allows the creation of a flat ground surface and stabilises the machine on uneven ground. It also protects the undercarriage and crawler drives against impacts from rubble.
These innovations – from diamond-enhanced cutting technology to specialized excavators and trenchless pipe installation – reflect a broader trend in the tunnelling and underground construction industries. By focusing on efficiency, precision, and minimizing environmental impact, these advancements promise to make tunnelling safer, faster, and more sustainable for a variety of critical infrastructure projects.
