12.4 km second aqueduct being driven by 7.2 m Robbins variable frequency drive, single shield TBM in deformed Palaeozoic rocks including abrasive quartzite and compact green schist with UCS of 33 to 120 Mpa with fractures and faults. TBM equipped with back-loading 17 in wedge-block cutters; rotary segment erector for six-piece precast concrete lining; ZED guidance system and automatic thrust control and steering. April 1995.
