These doors are the enterance to the tunnel portal which leads to the Rangipo underground power station.
Area reached via Kaimanawa Road, turn off SH 1 16 km's Sth of Turangi, There is a phone at the tunnel portal don't let kids fiddle, and there is a security camera watching the phone......be warned :) Cache is a sistema 200ml container, with log and pencil.
First to Find: petey