Down to “Middle Earth” - According to the Bus Driver

Our next part to the adventure was to travel 2 km underground to visit the Generating Chamber of the Manapouri Power Station.   This was one of the all time great engineering feats in NZ history.    Tunnels were blasted out of the super hard quartz ridden rock to funnel water from Lake Manapouri down vertical tunnels to spin the power turbines at the bottom in the huge underground power chamber which stands 200m below the surface of Lake Manapouri.
The tailrace tunnels are 10km long and 10m wide, the first tunnel being constructed by the drill and blast method and been lined to leave a smooth surface.   The second was achieved with a Tunnel Boring Machine.   These take the water from the turbines out into Doubtful Sound

The Tunnel Entrance

The tunnel is 9m wide, and built to take the largest pieces of machinery down to the bottom.   Trucks delivering parts had to back down the tunnel and a delivery could take up to 7 hours.   There’s room enough for two vehicles but with a bus this size it takes a skilled driver to manoeuvre down the winding tunnel.    Vehicles in the tunnel drive on the right hand side so the drivers can better judge the distances to the rock walls.   At the bottom the driver has to turn the bus with a multi faceted turn across the narrow width to face outwards for the journey back.   A feat that generated spontaneous applause from the impressed passengers on board.

The whole project took 1800 workers eight years to complete in the harsh conditions.   16 miners died in the construction of this power station and their names are commemorated on a plaque at the entrance to the generating hall.   Health and safety was not a priority in those days.

A short walk into the generating hall where we received an informative talk from the guide.

     The Generating Hall                                The Tunnel In
Most of the power generated here is destined for the Tiwai Point Aluminium smelter at Bluff.
Back on the bus and we slowly wound our way back up into the sunlight for our ferry trip back to Pearl Harbour in Lake Manapouri.