Paterson, B.R. 1974 A geological report on the Otukou Quarry (R9), Tongariro power development. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 178 4 p.
Abstract: This report was requested by the Ministry of Works, Turangi to assist in the assessment of the existing Otukou quarry as a future supply of rock for riprap, and other hard rocks required in the T.P.D. area. This deposit of andesite was first investigated by the consultants to the Ministry of Works, Sir Alexander Gibb and Partners, with the view to using the rock as shoulder material during the construction of the Otamangakau and Wanganui Diversion Dams. It was not used for this purpose but the best results of the investigation are reported in the consultants' Report of Investigations, Volume IV pp91-93. The quarry was first developed primarily as a crushed-rock source. It is now proposed to re-open the quarry to supply crushed rock for roading and other purposes, as well as riprap for lining canal embarkments. Prior to the opening of the quarry by the Ministry of Works, some exploratory drilling was carried out in 1964 to prove the depth of overburden and the quantity of rock available. Neither the core logs or the core have been located, although two plans are available (TPD 8404/2/3,4) showing the locations of the drill holes, and cross sections with summary drill hole logs. Two main considerations have been evaluated in this report: (1) the quantity of rock available, (2) the quality of the rock in terms of the variable requirements. No additional investigations were undertaken for the purpose of this report. (auth)