Detailed geological investigations were made of two previously selected dam sites, B and A, in the Upper Cotter Valley. Site B1 is geologically suitable for the construction of a dam, but subsequent to the investigation it was found that the storage capacity of this site would be insufficient for Canberra's estimated requirements; hence the site is unlikely to receive further consideration. Site A appears suitable for the construction of a stable dam, though less suitable geologically than site B1. Five recommendations are submitted for consideration.

A field party from the Bureau of Mineral Resources left Melbourne on 19th March, 1949, together with a relief party from the Australian National Antarctic Research Expedition. The objects of the party's visit to Macquarie Island were the establishment of a Seismological Observatory, the determination of the secular variation of magnetic declination, and the location of magnetically suitable areas for a proposed Magnetic Observatory. The present preliminary report is concerned exclusively with an accident which occurred during the construction of the Seismological Observatory and which caused injuries to A.B. Billan, R.A.N. The building plans and choice of the site are discussed.

This report is written in advance of the main report in order that a drilling campaign to test the scheelite deposits can be considered immediately. The descriptions are necessarily brief and moreover the report is not accompanied by the full set of plates which will accompany the main report. Present values suggest that the scheelite deposits could be worked on a much larger scale than the present one. The King Island scheelite mines have been operated during two periods, the first being between 1917 and 1920, and the second from 1938 to date. During the first period 67,710 tons of ore were treated for a production of 589 tons of scheelite concentrate, the average yield of concentrate being 0.87 per cent. During the second period 98,305 tons of ore were treated for a production of 627 tons of scheelite concentrate, the average yield on concentrate being 0.64 per cent. In addition and during the latter period 41,260 tons of tailings were re-treated for a production of 52 tons of scheelite concentrate, the average yield being 0.12 per cent. The mine is being worked at present and some 30,000 tons of ore are treated annually for a recovery of 200 tons of scheelite concentrate.

The principal alternative sites for an administrative centre which have been considered or suggested are discussed from the points of view with which a geologist and vulcanologist is primarily concerned - namely vulnerability to volcanic action, earthquakes, and tidal waves, foundations, water supply and accessibility of material suitable for road resurfacing, aggregate, etc. The areas considered are Rabaul, Nonga-Tavui, Keravat-Kabaira, Vunakanau-Taliligap, and Koko-Rapopo.

On May 3rd, and again on June 1st, the author visited the Cotter dam to investigate a reported loss of water from the fault on the northern side of the wall. This report gives an account of these visits, together with the author's observations and conclusions in relation to the reported water loss.

In response to the proposal for a new administrative building to be erected, 1/4 mile east of Parliament House, nine test pits were put down by the Department of the Interior for the purpose of examining the sub-surface conditions. Four of the pits were used for engineering tests of the bearing power of the rock foundations. The geology of the site is discussed in this report.

Details and results are given of a seismic refraction survey made at the request of the Hydro-Electric Commission of Tasmania, to investigate the site of the western portal of the proposed Mossy Marsh Tunnel. The tunnel is part of the No. 2 Tarraleah Canal project to transport water from Lake King William to Tarraleah Power Station. The primary object of the survey was to determine the thickness of till overlying the dolerite bedrock, and hence contours of the bedrock surface.

The overburden (or non-scheelite bearing rocks overlying the ore-bearing rocks) at the mine of the King Scheelite N.L. at Grassy include: 1) A layer of windblown sand ranging in thickness up to 30 feet; 2) An irregular layer of non-mineralised rocks occurring in the north-western part of the present workings; 3) Non-mineralised rocks conformably overlying the lode in the southern part of the workings; 4) Overburden dumped on the southern side of the open cut. The problem of the dumping of the overburden is involved in that of the selection of a suitable site for the treatment plant. Under the proposed scheme to increase production a new site will have to be found for the treatment plant that is to be erected.

This geological report on the Jervis Bay firebrick clay deposit and the Jervis Bay aerodrome is comprised in three distinct sections. The first discusses the situation and production history of the area, and describes the geological surveys completed to date. The second describes the geology and topography of the aerodrome. The final section describes the investigation of the firebrick clay and the results of this investigation, with reference to the aerodrome and the proposal for a new runway. Accompanying plans of the clay deposit and the aerodrome are included.

The Commonwealth Flax Production Committee conducts a flax mill at Ballarat. The flax is first treated with water and 25,000 gallons per day are used in the process. After the treatment, the water is allowed to run to waste, and is at present being conducted through an earthen drain to natural drainage channels. This disposal of effluent water is not approved by the Ballarat Council, and other means of disposal have to be found. The objective of the present investigation was to determine if another borehole could be suitably sited to dispose of the effluent. The geology of the area, possibilities of disposal, and recommendations are discussed in this report. Two accompanying plates are included.