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The Oaklands-Coorabin Coalfield in the Riverina Division of New South Wales has been known for many years. Coal is produced from a small colliery near Coorabin and a minor amount of exploratory drilling in the general vicinity of this mine has been carried out by New South Wales and Commonwealth Government authorities. This exploration has shown that coal seams extend over an area of a few square miles near Coorabin. The coal occurs in Permian rocks which do not crop out but are covered by Tertiary and younger sediments with a minimum thickness of 100 feet. Examination of the regional geology led to the conclusion that the coalfield is far more extensive than the limited area proved by drilling. Because of the Tertiary cover, normal geological methods cannot be used to map the boundaries of the Coal Measures and for this reason geophysical survey's, which have been used successfully on similar problems elsewhere, were undertaken to map the sedimentary basin. A gravity survey was carried out first and as the work proceeded it became obvious that a pronounced regional anomaly is present. Consequently, seismic methods were employed to try to obtain the thickness of the sediments at a number of critical places and to provide a control for separating the effect of the sediments from the regional effect. A residual gravity contour plan was obtained and indicates the general shape of the sedimentary basin. This plan provides a satisfactory basis for recommending drilling to test the potentialities of the basin. An area of approximately 1,450 square miles was covered by the geophysical surveys and, after correcting for regional effect, the residual gravity pattern suggests the presence of a Permian basin approximately 600 square miles in area, with a possible extension in a north-westerly direction. Recommendations are made for testing the geophysical results by drilling at five widely-spaced sites in the supposed basin. Five additional drilling sites are recommended and are designed to prove reserves near the known coal occurrences.

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In Portion 11, Ph. of Stockrington Diamond Drilling near an unnamed creek tributary to Surveyor Creek has disclosed coal continuously for a distance of 7,600 feet south from the northern boundary of the Portion. The seam is split and banded and the coal is inherently high in ash. Proximate analyses of the coal were carried out by the New South Wales Mines Department laboratory in Sydney. All coal ores were forwarded from the field and shale etc. bands of greater thickness than half an inch were discarded by the analysts. Stony coal or carbonaceous shale with S.G. greater than 1.6 was also rejected from the assay samples. Consequently the analyses quoted indicate a composition roughly equivalent to that which might be expected for cleaned or hand-picked coal from this area.

This Bulletin presents an account of the general geology, stratigraphy, structure, and mineral resources of the Brock's Creek district, Northern Territory. The general geological mapping of the district was carried out by the Aerial, Geological, and Geophysical Survey of Northern Australia in 1939, and a brief account of the results then obtained has been published (A.G.G.S.N.A., 1939). Some further mapping was carried out in 1950. The most important sedimentary rocks of the district are believed to be of Lower Proterozoic age and have been called the Brocks Creek Group (Noakes, 1949). They are dominantly argillaceous in type, but contain sandy formations as well as thin beds of conglomerate and limestone. Numerous sills of amphibolite, which are of igneous origin, are found within the sedimentary sequence. The sediments and interrelated amphibolites probably attain a thickness of 18,000 feet. Unconformably overlying the Brock's Creek Group is a comparatively thin formation of quartzite which is probably late Proterozoic, in age and is known as the Ruldiva Quartzite. Horizontally bedded Lower Cretaceous sandstone and shale up to 200 feet, thick is found capping mesas ill the district. In the north-eastern section of the area mapped is a concordant body of granite (Brock's Creek Granite), roughly circular in shape at the surface, and haying an average diameter of approximately six miles. A smaller area of concordant granite occurs near Mt. Shoobridge in the south-western portion of the area mapped. A discordant cross-cutting granite (Margaret Granite) cuts through the Brock's Creek sediments in the south-eastern portion of the district and exends for many miles to the south. The Buldiva Quartzite is only gently folded and is not intruded by igneous rocks, but the Brocks Creek Group has been subjected to considerable folding and faulting. The fold axes trend north-westerly or northerly, and marked cleavage has been produced parallel to the fold axes. The fine-grained sediments have been converted into schist in many places. Comparatively broad domal and basin-shape1 folds dominate the general structure of the district, but some anticlinal folds have been comparatively tightly compressed---e.g., the Howley Anticline. Within the 300 square miles of country mapped, it was found that deposits of gold and copper occur within, or close to, one formation, which may be repeated from place to place by folding and faulting. The favourable formation is a graphitic slate but is closely associated with a thin band of conglomerate and is normally associated also with sills of amphibolite. A limestone commonly occurs above or below the graphitic slate, but is lenticular in habit. Ore is commonly found in domal and anticlinal structures within these beds, especially near the more crenulated portions of the structure.

This report presents the results of detailed geological mapping of an area of approximately seven square miles surrounding the Mount Elliott copper mine, Selwyn, Queensland. The survey was made to determine the relationship between the geological structure and the mineralized zone containing the Mount Elliott copper deposit. A geological map of the actual exposures has been compiled (Plate 1) and interpretations of this data are shown on one plan (Plate 2) and eight sections (Plates 3, 4, 5 and 6). This report is intended as a supplement to the report by C.J. Sullivan (1951) and should be read in conjunction with it.

The purpose of a visit to the Cloncurry district, which lasted from 21st August to 30th September, 1951, was to see what aid geophysical work could give in the search for copper deposits in this field which is one of the biggest mineral fields in Australia. While the Cloncurry district in the past produced copper from many small but rich deposits, only a few exceeded 200,000 tons, and the search now is being conducted mainly with the idea of finding and developing huge but relatively low grade copper deposits with at least several hundred thousand tons, or perhaps millions of tons of copper ore containing at least 2.5 to 5 percent copper. It is possible that geophysics might help in this search, and consequently, a number of old copper mines were visited and some geophysical test traverses made. With the rather limited facilities available the tests were confined to self-potential measurements and to a few traverses with a new Atlas gravity meter, especially suitable for ore prospecting because of its lights weight and transportability and its high sensitivity and accuracy. This report gives an account of the survey and its results.

In October, 1951, geologists G.F. Joklik and S.A. Tomich from the Harts range party of the Commonwealth Bureau of Mineral Resources inspected the section along the Ross River in the Fergusson Ranges fifty miles east of Alice Springs. They collected fossils from several localities discovered by C.T. Madigan, who had regarded the high fossiliferous horizon as basal Larapintine. He describes the rocks as 'worm-eaten quartzite, with moulds suggesting Isoarca' and remarks that 'no good fossils were found'. It is this bed that has yielded the Upper Cambrian fossils. Fossils collected in the deeper horizon generally confirm Madigan's observations. The results of this investigation are recorded and discussed in this report.

Howards Springs are situated about 3.5 miles north-east of a point on the Stuart highway about 16 miles south of Darwin. They are seepage springs on a branch of the Howard River. Radioactive material was found in the area by Mr. L. Good, Box 273, Darwin, during October, and samples were sent to Rum Jungle for testing. A brief inspection of the area was made by the writer and Dr. N.H. Fisher on 7th November, 1952. It seems likely that the mineral causing radioactivity has been precipitated, probably by organic matter, from the spring water in the black clay layer, but the original source of the material is not at present clear.

The area tested by drilling comprises approximately 30 acres of the Parish of Cullen Bullen in the County of Roxburgh, and is immediately to the east of the Portland-Mudgee railway line about 1.5 miles northward from Cullen Bullen Station. The purpose of drilling was to test the Irondale and Lithgow seams of the Upper Coal-Measures for thickness and quality, and thus determine whether or not the more detailed investigation of proving is warranted. Seven holes, with an average depth of 116 feet, were drilled by Goldfields Diamond Drilling Co. under contract to the bureau of near sites chosen by the Geological Survey of N.S.W. The total footage drilled was 810 feet and coal-core recovery averaged 89%. Core drilling in the Tyldesley Area has indicated the presence of 41,000 tons of banded high-ash coal in the lower split of the Lithgow Seam. The coal is considered unsuitable for exploitation by open cut methods and a proving campaign is not recommended.