Hegan, B.D. 1978 Engineering geology of the outlet leg of the Rangipo tailrace tunnel. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 305 13 p.
Abstract: Subsequent to issuing report NZGS EG 253, Engineering Geology of the Tailrace Tunnel in 1976, two further investigation drillholes and the excavation of an access adit have been completed. This report presents this additional information, and outlines anticipated tunnelling conditions in the outlet leg of the tailrace tunnel. (auth)