Design and construct contract awarded to Miller Civil Engineering by Southern Water value $71 million. Herrenknecht 7.4 m Mixshield boring 1.6 km x 6.5 m i.d. storage tunnel at depths of 20 m to 60 m in ground conditions ranging from solid rock to running sand with high water pressures. 800 kW variable speed, bi-directional drive cutterhead. Built-in stone crusher behind cutter wheel. 6.6 m internal diameter precast concrete lining with seven gasketed segments and key. Annulus grouted systematically to minimise settlement. Possible hazards include methane, carbon dioxide and contaminated ground. Completion June, 2000. August 1998.  Herrenknecht Mixshield with VMT guidance system completed main drive mid-August, 1999. Best daily advance 21 m, or fourteen 1.5 m rings on two shifts. Fully-gasketed Charcon seven segment plus key lining with 7.36 m outside diameter. Erection time 15 min. Clayton locomotives and Wheel Sets rolling stock. Sept 1999.