Dominican Republic, San Juan de la Maguana
2009 – 2011
High-performance tunnelling

The Dominican Republic hoped to reduce its dependence on crude oil. Hence the Palomino hydroelectric plant in the southwest of the island state which plans to supply the Dominican power grid with around 80 Megawatts, dispensing with imports of 400,000 barrels of crude oil every year.

A Herrenknecht tunnel boring machine was used for the first time in the Caribbean for the 12.4-kilometer supply tunnel to the hydroelectric power plant. Starting in August 2009, the S-494 (Ø 4,500mm) Double Shield TBM bored its way through complex consolidated rock formations with overburdens of up to 525 meters. After a steep learning curve, the site team achieved top weekly performances of over 250 meters. 99.9 percent of the entiere tunnel length were driven continiously , i.e. excavating and positioning rings at the same time.

For these top figures, the building contractor placed his trust in the integrated solutions from the Herrenknecht Group: jobsite service, high-precision mould systems from Formwork, rail-bound transport systems from MSD and navigation and laser technology from VMT. After only eleven months, S-494 arrived at the target shaft on March 23, 2011.

Data Sheet

Country, Location

Dominican Republic, San Juan de la Maguana


2009 – 2011




Marl, sandstone, limestone

Tunnelling length

12,436 m

Machine Data

1x Double Shield TBM:
Diameter: 4,500 mm
Lining method: Segmental lining
Cutterhead power: 1,400 kW
Torque: 1,694 kNm

Your contact person Contact us

Steffen Dubé President and General Manager Herrenknecht Tunnelling Systems USA Inc.
Gerhard Goisser Commercial Manager Herrenknecht Tunnelling Systems USA, Inc.