Results are given of a geophysical test survey made at three localities on the Newcastle coalfield in August, 1952, to determine whether intrusive doleritic dykes could be located by the magnetic method. Knowledge of the position of the dykes would assist in planning the lay-out of underground workings and of surface roads. The results showed only slight variations of the magnetic field, but some weak anomalies of less than 100 gammas were recorded. The position of these anomalies coincides with the inferred position of the basic dykes near the surface. The variation in the shape of anomalies suggests non-uniformity of the magnetic properties and shape of the dykes. The magnetic method might be helpful in determining the position and extent of the dykes beyond the areas where they are known, but supporting evidence from other geophysical methods such as the gravity of electric resistivity methods may be needed to verify the magnetic results.

A request was received in December, 1951, from the Director of Ordnance and Underwater Weapons of the Department of the Navy for assistance in selecting an area suitable for the electrical balance testing of the pistol-firing rod unit of the torpedo. It was desired that this site should be at the R.A.N. Torpedo Establishment at Neutral Bay, Sydney, New South Wales. The only condition laid down in the relevant specification is that "the rod may be supported in a suitable wooden structure or in such other manner provided that the complete rod unit is not less than ten feet from any ferro-magnetic materials". In order to arrive at a more specific definition of the requirements for the testing site, the problem was discussed with the Chief Superintendent and officers of the Torpedo Establishment. The appropriate test specifications were consulted and a series of measurements were carried out to determine the actual requirements. The magnetic investigations described in this report were carried out in August, 1952, and the overall results and conclusions were communicated verbally at that time to the officers concerned.

Bore No. 8287, Mr. E.J. Riches, "Myrnong", Bourke - Thirteen samples were submitted for examination from this bore. A detailed examination of these is given below. Bore No. 4676, P. Mallon, "Avoca", Bourke - Fourteen samples were submitted from this bore and a detailed examination of them is as follows.

Six wax-sealed samples of cores were received with a request that they be tested for porosity, permeability and oil and water content. Testing was carried out by Messrs. N.V.H. Hoyling and H.S. Taylor-Rogers at the Newcastle Technical College - to the Principal and Staff of which institution grateful acknowledgment of their co-operation and utilization of their apparatus and laboratory space is made.

In connection with the search for uranium in Australia samples of mill products from producing mines have been examined for radioactivity by the Bureau. Amongst these were several samples from mines at Broken Hill. A preliminary examination showed that the uranium content of the samples was certainly much less than 0.01 per cent. To obtain more accurate data, the samples were re-examined by more sensitive methods, and the results of these are tabulated below.

The London Bridge Limestone has been traced along its strike from a point five miles south-south-east of Queanbeyan to a point three miles south-east of Bredbo, a distance of forty miles. At London Bridge this formation attains its greatest development and a large-scale geological map of this area has been prepared. Fossil collections have been made from localities along this formation and the fauna has been examined. A description of the coral Pycnostylus ? sp. nov. is given. The stratigraphical position of this formation has been placed within the Wenlock Epoch, possibly within the Lower Wenlock.

The features of the single-point resistance log, obtained in A.A.O. No. 2 Bore, Roma, are described. Single-point resistance, self-potential and geological logs of the lower section of the boreholes are shown. The results indicate that electrical logging can be effectively used for correlation problems and that salt water sands in the reservoir rocks can be detected with reasonable certainty.

This report is concerned with the bryozoan faunas of the Nura Nura limestone and the Noonkanbah series. The bryozoan faunas from individual localities and the distribution of species occurring in areas other than the Kimberley district are listed. Other aspects of the faunas are discussed. This discussion includes a general consideration of the facies, a description of the faunas of the Nura Nura Limestone, and a comparison with other Permian faunas. A supplementary list of the bryozoan faunas of localities in the Noonkanbah series represented by the Teichert's specimens is included.

This statement has been prepared as a supplement to Summary Report No. 27 - Aluminium and Bauxite - which was issued in 1946. Since that year testing of deposits in Tasmania has been completed and new discoveries of commercial bauxite have been made in northern New South Wales and the Northern Territory. Further exploration in South Gippsland has resulted in minor additions to the proved reserves of Victoria, and the presence of bauxite has been reported in Papua and New Guinea. Exploration of deposits of bauxite on the north coast of the Northern Territory is not complete but sufficient accessible reserves have been proved to change the formerly unfavourable outlook for the aluminium industry now being established in Australia. Re-examination of the formerly known deposits has necessitated recalculation of the stated reserves, and has generally resulted in a reduction of the earlier estimates, but on the other hand a substantial increase has been made for the Tamborine Mountain deposits in Queensland. South Gippsland tonnages have been recalculated and expressed as dry ore so as to be consistent with the statements for other States. Tonnages throughout are long tons (2240 pounds) of dry ore. In the following tables proved reserves are those which have been systematically tested by pits or bores regularly spaced at intervals of not more than 400 feet, and in many cases only 100 feet. Indicated reserves have been tested by more widely or irregularly spaced holes.

Investigations into the geological structure of the immediate area of the mine are not complete. Various structural controls have been recognised in the Main Lode. The South Lode is mostly hidden under alluvium, but similar structures trend across the area. The possibility of a repetition copper lode in the South Lode area is hopeful. [The characteristics of the lodes and their ore reserves are discussed].