Hancox, G.T. 1975 Results of geological investigations for the Rangipo underground powerhouse (January 1974 - September 1975). Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 239 14 p.
Abstract: The purpose of this report is to present the results of geological investigations for the Rangipo Underground powerhouse that were carried out between January 1974 and September 1975. The investigations carried out during this period included:- a)Investigation shaft to depth of 85m with a pumping gallery at 40m and a drilling base chamber at 82m. b) Three diamond drillholes (R230, R232 and R233) were drilled from the base of the shaft to investigate rock conditions W and NE of the proposed powerhouse site. (auth)