Thanks Mike, and Solarpowered for your replies re SH 1 and the link tio the big tunnel bore machines.
The great part here near Puhoi was, that I had access to the electrical site of it and was allowed to take some photo's of it.
HighPotter The drill arm can swivel up and side wards. In the first stage the upper part of the tunnel arch is done, then the middle, and as last the lower part of the arch.
In the 1980's a tunnel was drilled for the Te Rapa to Tauranga railway, through the Kaimai ranges, this one had a full diametre drill of the actual tunnel bore, the remains of that machine are still dumped at the eastern entrance to the tunnel.
The plan is for 2 tunnels approx 10 * 14 Metres diametre, what the on site guys told me.
