More than one thousand Microtunnelling machines sold in the last 20 years ? Herrenknecht is the world?s leading manufacturer of tunnelling technology in the diameter range up to 4.20m.

The segment ?Utility Tunnelling? started almost 20 years ago. According to the motto ?it?s better to start small and finish big than vice versa?, Herrenknecht launched ?Microtunnelling? technology for non-accessible diameters in 1986. In cooperation with the ?Bundesministerium für Bildung und Forschung? (Federal Ministry for Education and Research) and supported by promotional funds amounting to DM 500,000, Herrenknecht developed a slurry Pipe Jacking system that could install DN500 pipes in the groundwater-bearing European soils. The first prototype of the slurry machine was deployed during a drainage project by the City of Hamburg, Germany.

Based on this experience, a simplified machine design was developed, convincing contractors, engineers and owners of the capabilities of microtunneling technology. The diameter range has continuously been extended ? according to market requirements ? and the so-called AVN machines (German acronym for ?Automatischer Vortrieb Nass? which means ?Automated Tunnelling Wet?) have become a top seller throughout Europe. Until today, more than 500 machines of this type have been sold.

In the early nineties, up to 70 machines were utilized on sewage and water projects in Germany alone. Legendary and unparalleled to this day is the project ?Europipe?. In only 100 days and without impacting the environmentally sensitive area, a 2.5km long pipeline, without intermediate shaft, was installed in 1992 with a AVND 3000 under the North Sea. This record has yet to be broken.

With continuous process innovations and a consequential transfer of know-how to local markets, Herrenknecht has gradually expanded and internationalized its business activities and operations in mechanized Utility Tunnelling.

1990 to 2000:

• Successful deployment of the Pipe Arch method: Through an arch of interlocked small-diameter casings, a short and large cross-section tunnel passage can be constructed under railroads, dams and roads.
• Machines for pure hard-rock tunnelling have been introduced.
• Open-center drive units in the range ?AVN1200T? allow access to the cutterhead to exchange tools during long tunnel drives in rock.

2000 to 2005:

• Driving first long-distance alignments in the Pipe Jacking method during river crossings of more than 800 meters.
• Introducing heavy-duty Horizontal Directional Drilling rigs to the market with pull forces up to 600t for a remote controlled installation of oil and gas pipelines.
• Development of the EPB technology (Earth Pressure Balance Shields) for small diameters (up to 1.40m machine diameter).
• Utilization of airlock technology for high pressures and integration of complex backup installations in the segmental-lining method up to 4.20m.
• Development and use of Shaft Sinking Equipment for the mechanized vertical sinking of shafts up to 12m diameter even in groundwater.

Today, Herrenknecht Utility Tunnelling Equipment is deployed in almost any region of the globe. Trenchless technology continues to gain ground and to prove its advantages over conventional methods to a greater degree. Europe is still Herrenknecht?s core market. Due to the growth of the worldwide service and sales network, the company has been able to grow in the markets of the Middle East, the US, Eastern Europe and the Asian-Pacific area over the last few years.

Herrenknecht continues to secure its market position in future through a fast and efficient, world-wide After-Sales network. What started almost 20 years ago as business with only few employees has become a main pillar of Herrenknecht AG activities under the direction of Werner Suhm, Member of the Board of Management.

?In the last 20 years, we?ve been able to achieve impressive technological developments, together with our contractors, clients, planners as well as research institutes,? reviews Werner Suhm. ?Based on that, we can focus entirely on offering our customers more comprehensive service and the most innovative project solutions possible. If we provide our customers with better concepts in terms of safety, efficiency and service, they will have the decisive advantage