Legacy product - no abstract available

Legacy product - no abstract available

The area investigated lies on the outskirts of Kotara, a suburb in the S.W. of Newcastle. The coal of interest is in the Burwood Seam. Drilling, field work, and surveying were carried out in the area. These operations are described in this report. Drilling results are discussed.

With Australia's postwar immigration programme and the increased demand for food supplies, an expansion of Australia's rural industries is of primary importance, both to increase domestic food supplies and to obtain foreign exchange by export of primary produce. For such a development, the rainfall, surface and underground water resources are the factors of prime importance. In West Australia the difficulties met in finding water for farming purposes prevents rational development of many rural areas. Also, in some places town water supplies are insufficient or the water is saline. Water resources may be classified as follow: rain water from tanks or dams, water from bores or wells, water from old mine shafts (in mining districts), water from springs, [and] water from rivers. The present investigations are not concerned with the last two types of water supply. The following aims were set. 1. To test several types of instruments, to discover their limitations and ranges and the optimum conditions for their operations. 2. To estimate the accuracy of depth determination to discontinuities which might be related to the geology. 3. To investigate the possibility of distinguishing the nature of the discontinuities, for instance, decomposed granite, fresh granite, ground water level, etc., and the possibility of estimating whether ground water is fresh, brackish or saline. The tests areas were selected in the belief that sufficient bore information would be available to serve as controls. However, except at Austin Downs, near Cue, and at Big Bell, the bore information was generally insufficient, vague and unreliable. With the exceptions mentioned above, adequate records had not been kept. The purpose of the geophysical survey was not primarily to search for areas with favourable ground water occurrences but to test the resistivity method in areas where information on the occurrence of ground water was available from existing wells and bores. The order in which the tests are described in the report is: Wubin, Cue, Big Bell, Lake Grace and Kulkin.

Samples from three bores in the Great Artesian Basin in Northern New South Wales were submitted by the Water Conservation and Irrigation Commission of New South Wales for micropalaeontological examination. These bores are: Bore No. 8256, M.E. Howe, "Retreat", Dubbo, Bore No. 8259, L. Fitzell, "Marathon", Dubbo, [and] Bore No. 8264, E.W. Robinson, "Womparley", Bourke. The results of the detailed examination of the samples are given below.

In the search for deposits of radioactive minerals in Australia the area of the Barrier Ranges appears especially worthy of investigation on geological grounds because it is composed of highly mineralised pre-Cambrian rocks. Mines in this area comprise the major producing mines along the main Broken Hill lode, one developed mine of less importance (the Pinnacles), and a number of small silver, lead and copper mines scattered over the surrounding district. The present report deals with the results of a reconnaissance radio-active survey performed by the Geophysical Section of the Bureau during July and August, 1950. The work was confined to the smaller mines, attention being directed, in the first instance to the mines from which radio-active museum specimens were stated to have come. At each mine the following tests were performed: tests on dumps and residues to discover whether any quantity of stone carrying a significant content of radio-active minerals had been broken during mining operations, tests on accessible exposed faces, and tests on rocks surrounding the mines. The tests were made with portable Geiger-Mueller rate-meters. Readings taken are quoted as multiples of background count, which has been considered as a constant characteristic of the instruments, rather than as the general reading obtained on country rock in the area. In most areas these methods of defining background would lead to the same result. As mentioned later, however, in the Broken Hill area this is not the case. Generally, the schists and gneisses on this field are definitely radio-active, and a true background reading, indicative of the complete absence of radio-active minerals, is obtained only on basic rocks. A reconnaissance survey was also made over the Euriowie tin field. Tests were also made around felspar quarries at Egebeck.

For the evaluation of the petroleum prospects of a sedimentary basin, the following factors are generally considered. Lithology, mode of deposition, thickness of the sediments contained in the basin, source and reservoir rocks. Facies of the sediments, changes in facies and the trends of such facies changes. Relationship of the various formations to each other - conformity, disconformity, unconformity, regressive and transgressive overlap, erosional gaps and their significance structurally and for accumulation. Direct or indirect evidence for the presence of oil - seepages, traces or showings of bitumen, oil and/or gas existing bores, bituminous character of some of the stratigraphic members. Tectonics - folding (single phase, multiple phase), faulting, tectonic history and its bearing on migration and accumulation of oil. Types of tectonic traps, and stratigraphic traps in relation to folding and faulting (sandy facies near basement uplift, reef formation on crests of rising anticlines, sandy facies in connection with ancient fault lines). Some of these criteria can be applied to the North-West and the Fitzroy Basins, but it is realized that the information available is not complete enough yet to fully discuss all aspects involved. On the other hand it is felt that, at this stage, a brief review of the results already obtained can greatly assist in an outline of a future programme. It will be seen that much emphasis is laid on geophysical work i.e. gravity investigations for the regional aspect of the problem - the configuration of the basins - and seismic investigations of structures which are selected for deep testing. In our opinion the results obtained so far in the North-West Basin, by both types of geophysical work, have clearly demonstrated the soundness of this way of approach

The distribution of marine Tertiary rocks in Australia is restricted to the western and southern coastal areas of the continent. The rocks represented are of Paleocene, Eocene, Miocene and Pliocene ages. Considerable material has been collected in stratigraphic sequence from many Tertiary localities in recent years and the detailed examination of the foraminiferal content of the rocks has yielded many startling discoveries.

A brief geological examination of this deposit was made by the writer and D.N. Smith between 18th and 20th June, 1952. The deposit had been previously examined in 1951 by J. Daly of the Geophysical Section, Bureau of Mineral Resources, and by J.C. Lloyd of the N.S.W. Mines Department and the results of their investigation were available for reference. The radioactive area examined during the present investigation was an area of about 1/4 square mile of the volcanic flow in the north-eastern corner of portion 39. Samples of the quartz veinlets and of the volcanic rocks were collected, and tests carried out with the Laboratory Geiger counter in Canberra indicate that both are radioactive and that the radioactivity is slightly greater in the sample from the quartz veinlets.

The sample of diatomite submitted for micro-examination came from a low bed on Beach Range at 1,110 feet above sea-level. The results of the examination are described herein.