Rock with strengths of up to 180MPa on a tunnelling length of more than one kilomter was challenging the Herrenknecht AVND3200AH on its way under the Han River in Seoul. The machine and the excavation tools mastered the hard rock tunnelling with bravoura. At the end of February 2007, a prominent party gathered at the target shaft to celebrate the breakthrough.

Greater Seoul's population is estimated at more than 20 million which makes it one of the largest metropolitan regions in the world. About every second Korean lives in the nation's capital. Seoul's infrastructure planers and contractors make huge efforts to develop and build efficient systems for the supply of drinking water. The tunnel excavated and lined by the Herrenknecht machine delivers water to one of the newly built suburbs.