This work was undertaken to extend regional mapping in the central and western portions of the A.C.T. and to provide a geological map of the Cotter River Area for use in engineering investigations. The regional geology portion of the Cotter Valley between Gingera and Bull's Head had previously been mapped on a scale of 1/2 mile to the inch, and this map was extended, by the recent survey, northwards to the Territory border and north-easterly to the Murrumbidgee River.

The present report gives a detailed description of all samples received from Frome-Broken Hill Co. Pty. Ltd., together with some stratigraphical notes. A preliminary report on a selection of these samples (1947/076) was submitted in December, 1947.

This report describes the results of the micropalaeontological examination of five rock samples collected from the south side of the Desert Basin.

Brief description of diatomite from Tincurrin.

It has been fairly firmly established that the fineness of the gold in any ore deposit varies with the depth from the surface at which the deposit was formed and as a corollary to this, that it is dependent upon the temperature and pressure at the time of deposition. This relationship is such that, under certain conditions, the gold fineness, taken into consideration with other recognised criteria, furnishes a very sensitive and reliable guide to the relative temperature of ore formation, at least within the epithermal and the upper part of the mesothermal range. The definition, determination, relation to deposits, and application of gold fineness are discussed in this report.

At the request of the Broken Hill Proprietary a geophysical test survey, employing gravity and magnetic methods, was carried out near Wollongong, N.S.W. by geophysicists of the Bureau. The area over which these tests were made is part of the Southern Coalfield of N.S.W. and plans are being made to develop a colliery in it. The subsurface geology is known in part from five drill holes, namely, Nebo No. 2, 5, and 6 and Wongawilli No. 7 and 8. Basalt sills of considerable thickness were encountered in Nebo No. 6 and Wongawilli No. 8. The proximity of sills to the coal seams has resulted, in parts of the Southern Coalfield, in the cindering of the coal, and for this reason it is a matter of considerable importance in planning a colliery to know the area occupied by the sills. The technical aspects of testing, results, and conclusions are discussed in this report.

Following the recommendations of an earlier investigation, a visit was arranged in June, 1947, to inspect the deposits near Hampton, at Toowoomba, and in the South Burnett District. As a result of this inspection it was decided to start a testing campaign on Portion 194v, Wooroolin and to follow this work by testing in the vicinity of Portion 206v. The method to be employed and scope of any further work was to be modified in the light of experience gained at the first two areas, called Kingaroy No. 1 and Kingaroy No. 2 respectively. The geology of the area, methods of testing, and the nature of the laterite are described in this report. A comparison of the results of searches by the Queensland Geological Survey and by the Australian Aluminium Production Company is given. Accompanying plans are included.

The gravity survey covered by this report was undertaken at the request of the South Australian Department of Mines as part of the investigation of a proposed reservoir site ay Myponga, South Australia. Myponga is about 40 miles south of Adelaide and the proposed reservoir would serve Yankalilla and other neighbouring towns which at present have no reticulated water supply. The geology of the area, method and operations, results of the survey, and interpretations are discussed in this report. Two plans, one of the gravity survey, and one showing surface and gravity profiles, are included in this report.

A geological investigation was carried out by the writer. The aim was to check the previous mapping of the geology, and if necessary, to assist the Magnetician in locating a suitable site for magnetic observations. Some aspects of geomorphology, and the reconnaissance survey work carried out are discussed in this report.

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.