Specialised systems for tunnelling and mining

Underground tunnel construction: Once the rock has been excavated, the tunnel face is secured using rock bolts, reinforcement mesh and shotcrete. These measures stabilise the tunnel cross-section and ensure safe working conditions as tunnelling continues.
©MC-Bauchemie 2026

A drilling machine in action during conventional tunnel construction: hydraulic drilling arms are used to drill holes into the tunnel face and the tunnel wall in preparation for blasting, rock bolts or grouting. Once the rock has been excavated, the tunnel is secured using rock bolts and shotcrete. MCU offers product systems suitable for all these applications.
©MC-Bauchemie 2026

The core team of the MCU business unit in front of MC’s headquarters in Bottrop, from left to right: Alberto Rey, Oguzhan Hazoglu, Lars Langmaack, Jörg Stank, Kei Sato, Markus Treinen, Lucas Krüger and Dirk Uhlmann (see image on the right).
©MC-Bauchemie 2026

The wider MCU team consists of over 40 specialists spanning all continents. They provide technical consultancy and on-site implementation services for tunnelling and mining projects all over the world
©MC-Bauchemie 2026

Underground tunnel construction: Once the rock has been excavated, the tunnel face is secured using rock bolts, reinforcement mesh and shotcrete. These measures stabilise the tunnel cross-section and ensure safe working conditions as tunnelling continues.
©MC-Bauchemie 2026

A drilling machine in action during conventional tunnel construction: hydraulic drilling arms are used to drill holes into the tunnel face and the tunnel wall in preparation for blasting, rock bolts or grouting. Once the rock has been excavated, the tunnel is secured using rock bolts and shotcrete. MCU offers product systems suitable for all these applications.
©MC-Bauchemie 2026

The core team of the MCU business unit in front of MC’s headquarters in Bottrop, from left to right: Alberto Rey, Oguzhan Hazoglu, Lars Langmaack, Jörg Stank, Kei Sato, Markus Treinen, Lucas Krüger and Dirk Uhlmann (see image on the right).
©MC-Bauchemie 2026

The wider MCU team consists of over 40 specialists spanning all continents. They provide technical consultancy and on-site implementation services for tunnelling and mining projects all over the world
©MC-Bauchemie 2026

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Alongside these challenges, requirements for cost efficiency, sustainability and safety are steadily increasing. Construction timeframes are tightening, settlement requirements in urban areas are becoming more complex, and environmental regulations are becoming more stringent. At the same time, there is a growing demand for structures with long service lives and minimal maintenance cycles. 

In this environment, project success depends not on a single product but on the coordinated interaction of all participants and technologies. This is precisely where MCU comes in — focusing on tunnelling and mining. MCU does not regard underground construction as a sequence of individual chemical components but as integrated processes that must be approached systemically – from the tunnel face to the completed lining. 

Three underground worlds: different requirements, one system approach 

Whether mechanised tunnelling with tunnel boring machines (TBMs), conventional excavation in soft ground or hard rock, or production-oriented underground mining – each of these “worlds” follows its own principles. While TBM projects are highly automated, conventional tunnelling is more geology-driven and sensitive to execution. Mining, by contrast, focuses on short cycles, rapid re-entry times and maximum process reliability. What unites them is the requirement for precisely coordinated system solutions. MCU offers comprehensive concepts that can be tailored flexibly to specific project and site needs. 

Mechanised tunnelling (TBM): process reliability in continuous operation

In mechanised tunnelling, the stability of the overall process interaction determines schedule, cost and safety. Using TBMs, the necessary behaviour of the muck during excavation must be carefully created and controlled. EPB machines (Earth Pressure Balance) use the excavated soil as a support medium, whereas Slurry TBMs use bentonite suspensions. Different soil types – from sand and gravel to cohesive clays and mixed-face conditions – require precisely tailored conditioning systems.  

MCU considers the TBM as a unified system and supports projects comprehensively, from the face to the finished tunnel tube. Soil conditioning is the first decisive step. Modern foam and polymer systems ensure defined muck-flow characteristics, reduce internal friction, and enable smooth excavation. Thanks to innovative technologies such as MC-StartupFoam®, MC-RheoSand® and MC-RheoClay®, TBMs can operate efficiently and quickly not only in sands and clays but also through trench walls and safe havens. 

MC-SolidFoam® – The game changer 

A technological milestone is MC-SolidFoam®. Unlike conventional water-based foams, this system is based on a high-density suspension (HDSL). This significantly extends the range of applications for EPB machines. Even highly permeable soils or fault zones with minimal permissible settlement can now be managed effectively. 

What previously required costly machine modifications can now be quickly addressed through an intelligent combination of HDSL technology, foam systems and generator solutions. Initial projects, like the heat transfer tunnel under the River Elbe in Hamburg, Germany, showcase the potential of this technology. 

Maximum advance performance with controlled risks 

For Slurry-TBMs, MCU has developed additives and flocculation systems that stabilise suspensions, reduce clogging, and enable efficient separation even at high clay contents. The objective remains the same: maximum advance performance with controlled risk.  

Another critical area is the sealing of the machine itself. Specialised lubrication and sealing grease systems protect against the ingress of water and fine particles. This concept is complemented by precisely adapted pump technologies that safely convey highly viscous compounds like tail sealants.  

Annulus grouting is an important factor for minimising settlement and ensuring early and uniform load transfer to the segments. MCU offers 1K and 2K systems, as well as cement-free and permeable speciality solutions. MCU also supplies tailored concrete admixtures, fibres and curing systems for segment production – designed to withstand high jacking forces while ensuring high durability and perfect surface quality. 

Conventional tunnelling and mining: flexibility in variable ground conditions  

While TBM projects are highly industrialised, conventional tunnelling demands maximum adaptability. Excavation in soft ground or drill-and-blast methods in hard rock are characterised by variable geology and the immediate impact of execution quality on structural safety. Sprayed concrete plays a central role. It provides temporary ground support and stabilisation, as well as ensuring the structure's long-term durability. MCU offers a comprehensive range of admixtures, fibres, hydration control systems, and alkali-free accelerators. These products enable precise control of early and final strengths, ensuring safe advance cycles while minimising rebound losses. 

Targeted rebound control in shotcrete using MC-Montan ShotSol 

With MC-Montan ShotSol, MCU is pursuing a new, systematic approach to targeted rebound control in shotcrete. The intelligent combination of concrete design and additive technology significantly reduces rebound – and thus also material consumption. This not only improves cost-effectiveness but also optimises the working environment on the construction site. This creates clearly measurable technical and economic added value, especially in large tunnel cross-sections or in mining with high installation volumes. 

High early strength and short downtimes with the MC-Montan Shotcrete HA-X series  

In underground mining, the focus is not only on safety, but also on productivity and fast re-entry times. The MC-Montan Shotcrete HA-X series of alkali-free accelerators has been specifically developed to meet these requirements. Its exceptional storage stability, low dosage and reliable early strength development – even at low temperatures – ensure process reliability while simplifying on-site logistics and handling. 

The system is complemented by rock bolt grouting mortars, admixtures for backfilling and performance-enhancing additives such as MC-Montan Injekt CG Boost. The latter transforms conventional cements into highly stable, volume-stable grouting mortars with optimised flow properties and controlled expansion. This is crucial for secure anchoring and durable backfilling. 

Special tunnelling support systems 

No tunnel project proceeds exactly according to plan. Water ingress, cavities, cracking or unexpected ground conditions require rapid and technically reliable solutions. MCU addresses these demands with special tunnelling support systems. These include injection resins for ground stabilisation and waterproofing, as well as swelling systems for joint and crack repair. In addition, MCU offers the full range of MC-Bauchemie’s repair and surface protection systems for maintenance and asset preservation, including fire-tested concrete replacement materials and tunnel-specific OS coatings that protect against contamination and aggressive media.  

All of this ensures durability even under extreme loads. Particularly in these critical moments, the strength of an integrated system provider becomes evident. Chemistry, mechanical technology and on-site support function not as isolated measures, but as a coordinated overall concept. 

Sustainability and cost efficiency 

Sustainability in tunnelling and mining means more than simply reducing material consumption. It begins with biodegradable foams and groundwater-neutral injection systems, continues with cement-free or alkali-activated binders and extends to longer maintenance intervals and reduced downtime. 

Cost efficiency arises from process reliability. Every avoided interruption, every reduction in rebound and every optimised dosage has a direct impact on costs, resource consumption and the CO₂ balance. System-oriented solutions therefore contribute to both the ecological and economic optimisation of a project. 

MC Underground – system partner for complex underground projects 

With MCU, MC-Bauchemie consolidates its international expertise in underground construction within a specialised business unit. The clear focus is on TBM tunnelling, conventional tunnelling and mining, complemented by powerful special systems for unpredictable underground situations. These solutions are globally applicable and economically viable, while being locally adaptable to specific project requirements and implemented with technical precision. 

MCU thus provides clients, designers and contractors with system solutions for every excavation method supported by an international team of experts offering comprehensive assistance, from technical consultancy and training through to on-site implementation.