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The Frazer radioactive prospect was located by the Geophysical Section of the Bureau of Mineral Resources during Airborne Scintillometer and magnetometer surveys carried out during 1952 in a Dakota, VH-BUR, over country surrounding Rum Jungle. Radiometric Investigations showed that the radioactivity is confined to the ferruginous surface rocks which may represent a lateritic deposit. To the east of the costean occur a few low ridges comprising a hematite quartz quartzite breccia and a white quartz breccia. The hematite quartz quartzite breccia appears to overlie the white siliceous breccia. The ferruginous breccia exhibits some radioactivity and this may explain the occurrence of the radioactive laterite. No radioactive mineral can be defined.

In the search for deposits of radio-active minerals the Bureau has used scintillometer equipment mounted in a D.C.3 aircraft with considerable success in suitable country. In order to investigate the possibility of extending the application of this type of survey to mountainous country, over which the D.C.3 could not be used, tests of similar equipment mounted in a helicopter have been made over three areas in New South Wales. The areas selected were at Carcoar, Tenterfield and Broken Hill. The results of the tests indicate that a scintillometer mounted in a helicopter can be successfully used in almost any type of country. However, in areas of low relief, the D.C.3 aircraft is preferable, owing to its greater speed and to the fact that it can carry auxiliary equipment by means of which its position at any time can be accurately fixed. The helicopter will not give the rapid and complete routine coverage of large areas that is given by the D.C.3. In rugged or mountainous country where the larger aircraft cannot be used the helicopter offers great advantages over other methods of prospecting for radio-active deposits. For this work it is best operated by following flight lines related to easily identifiable map features.

The activity of Mount Lamington over the last half year has tended to confirm conclusions drawn from earlier observations, namely, that conditions of slow decline in overall activity pointed towards a return to the dormant state. There have been fluctuations in activity during this period, renewed dome building in some sectors of the crater and on one occasion, explosions were reported to have occurred near the dome summit.

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This report deals with the results of 25,000 ft. of boring over an area of 15 sq. miles. Twenty-six coal seams were identified and named. Total reserves of all seams with band-free thickness greater than 4.0 ft. are 200,000,000 tons. Net open-cut reserves (to 9:1 ratio) of 7,500,000 tons over an area of 400 acres were tested and defined on four seams. All work in the Howick Area was done in the period March, 1952, to June, 1953.

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].

The Crater Prospect is situated about 4 miles south-south-east of White's workings and 1 mile north-east of the junction of Batchelor Road and the Darwin-Birdum railway line. It is the name assigned to a type area of an extensive radioactive bed of conglomerate. Low grade but wide-spread radioactivity was discovered by R.S. Matheson and D.F. Dyson (geophysicists) in June 1951, while prospecting along the sedimentary beds out-cropping immediately south of the Rum Jungle granite on the south-side of Giant's Reef fault, and on the south side of another major parallel fault. Geiger-Muller traverses along the strike of a grit-conglomerate horizon away from the Crater prospect revealed that the radioactivity extends westwards for 1.5 miles and for half a mile to the east. The radioactivity, which was confined to the conglomerate, was low-grade and discontinuous over this distance of 2 miles. The Crater Prospect, which can be regarded as a type locality, was geologically mapped by the writer on a scale of 200 feet to one inch after the area had been radiometrically contoured, and the plan accompanies this report (Plate 1). [The geology and structure of the prospect, nature of the radioactivity, and prospecting recommendations are discussed].

Legacy product - no abstract available

Geochemical anomalies in soils over zones of lead mineralization were studied, both in known mineralized areas and in areas of suspected mineralization. The anomalies were readily detected and outlined by using a dithizone technique on acid extracts of soil samples collected from grid systems. By assuming the principles of mechanical mixing of the mineralized rock with other material during soil formation, and of downhill migration of soils, the anomalies were correlated with the zones of their origin: the asymmetric anomalies discovered are typical of such conditions. Applied to areas of suspected mineralization the geochemical prospecting was responsible for the discovery of two new bands of lead mineralization and several large lead and copper anomalies. The method proved to be extremely useful for indicating the most favourable areas for more detailed prospecting such as diamond or churn drilling and geophysical methods.