The prospect covers an area originally enclosing three first order and one second order anomaly located by the Airborne Scintillometer Survey if 1952. Preliminary ground investigation was carried out in October 1952 and is contained in 'Preliminary Report on Airborne Scintillometer Surveys by N.H. Fisher and J. Sleiss'. Carborne equipment was first used to locate the anomalies and determine their extent in July, 1953. An Auster aircraft carrying a Halross scintillometer also flew over the area at the same time locating a high only near the first zone. This was carried out by the Territory Enterprise Limited. A survey grid was laid down to serve both the geological and geophysical work. The base line runs north-south for 3,300 feet and traverse lines run across it at 100 ft. intervals. The detailed radioactive survey covered the whole area. Traverse lines were read at 300 foot intervals in the outer sections where closer work was not warranted. The work commenced in August and was completed in October 1953.

Brown's Deposit is the westernmost known area of mineralization in the Rum Jungle area. It is situated approximately two miles northeast of Rum Jungle Railway Siding and one mile southwest of White's Deposit in an area known as Brown's Workings, which was worked for copper in the early part of the century. In June 1950, preliminary geophysical investigations revealed that a radiometric anomaly was present at the eastern end of the old copper workings, and in October 1940, a self-potential survey (Allen 1950) indicated the presence of two distinct bodies of sulphide mineralization. During 1950 a geological map of the area on a scale of 100 feet to an inch was prepared, and in 1951 mapping of the area on a scale of 40 feet and 20 feet to an inch was commenced. This work at present remains unfinished due to other commitments. Three diamond drill holes, part of an extensive programme of diamond drilling planned for the area were drilled towards the end of 1951.

The area prospected is shown in plan on Plate 2 and a locality map is given in Plate 1. The prospecting was done by geologists D.E. Gardner and N.O. Jones, and survey hands S.J. Quain of the geological party, and B. Brewster and E. Rigby of the geophysical party. In order to cover the area systematically, it was subdivided into small topographic units, bounded by such features as creeks and the crest of ridges. Each unit of the area was traversed by one or more members of the prospecting party, who used Geiger-counters or ratemeters to test shear zones and outcropping quartz veins for radio-activity. Prospects were examined by either of the two geologists, who also made general notes on the geology of each unit of the prospecting area. Twelve uranium prospects were discovered within an area 4 miles long by 1.25 miles wide in Cullen granite adjacent to the contact with Brocks Creek sediments. An additional prospect was previously known to occur there. They are all small, and judging from the surface counts, appear to be low in grade.

During the 1953 field season geochemical prospecting techniques were employed as an additional tool in the search for ore deposits in the Northern Territory. Areas of particular interest were those at which radio-active minerals had already been discovered or at which radiometric anomalies were being investigated. The work thus included the already proved Rum Jungle field as well as the new prospects at Brodribb, Waterhouse, Edith River, and Coronation Hill. A direct chemical test for uranium in soils was not used, the discovery of the radio-active areas being left to the sensitive ratemeters now in use. The close association between copper and uranium was used to advantage as it is present at many of the uranium prospects in the Northern Territory. It is a logical step to use the geochemical techniques to locate new copper mineralization, and then to carry investigations further by attempting to locate uranium in the vicinity of the copper, particularly in areas covered by deep soils where ratemeters are of no use. A field test for cobalt, a metal often closely associated with both copper and uranium, was developed, but of the many samples tested for this element only one gave a positive test. It is possible that the cobalt, an element which is extremely mobile in the oxidized zone, has been completely leached and dispersed from the radio-active minerals.

This prospect was discovered by Geologist A.B. Clark on the 3rd September, 1953 at a point 11 miles distant and on a bearing of 33 degrees from the Katherine Post Office. Following its discovery a reservation was taken out on behalf of the Bureau of Mineral Resources to protect the area. Detailed geological and geophysical investigations have since been undertaken in the area, and costeaning by hand labour and bulldozer has also been done. The examination and testing of the prospect is not yet complete but a summary of the information concerning the prospect available at 31st October 1953 is given below.

During the 1952 field season a series of test traverses using magnetic and self-potential methods was carried out over the known radio-active deposits in the Rum Jungle area, to discover whether any definite anomalies were associated with surface showings of radio-active minerals. In the course of the magnetic work in Brown's area, a major magnetic anomaly was discovered south-west of the workings, and a reconnaissance magnetic survey was carried out in order to obtain information on its extent. [Technical details and the preliminary results of the survey are discussed in this report].

A geophysical survey, comprising self-potential and electromagnetic methods, was made during the 1952 and 1953 field seasons at the Labour Victory Copper Mine, about 7 miles north-north-west of the Mt. Elliott Copper Mine, near Selwyn, Northern Queensland. The self-potential survey covered an area of 2,400 feet x 900 feet, but owing to other operational commitments during the 1953 season, the electromagnetic survey was confined to the southern part of the area. The primary object of the work was to determine the extent of the mineralisation associated with the known lode, which strikes north-south through the centre of the surveyed area. The self-potential survey revealed a well-defined anomaly nearly 1,000 feet long, in the northern part of the area. The axis of this anomaly is parallel to, but about 75 feet west of, the known lode. The disused main shaft of the now idle mine is at the southern end of the anomaly, which in this vicinity deviates slightly towards the south-east, i.e. towards the known lode. No workings exist in the area of the indication, and no outcrops were found, the rock formations being hidden for the most part by alluvium. The electromagnetic results confirmed those of the self-potential survey, but the electromagnetic indication extends farther to the south. The results suggest that the indication may be caused by lenticular bodies and that these are disturbed by cross faults. No mineralised deposits were indicated by the electrical results in the southern part of the area. It is recommended that some trenching and geological and geochemical work be done in the area of the strong electrical indication. If the results of the testing show that the indication is not due to graphitic or pyritic schists, it is recommended that a number of diamond drill holes be put down. Suggested locations for five such drill holes are given. If the anomaly is due to ore the geophysical results suggest an ore body of considerable size.

Sediments of the Brock's Creek Group and of the Phillips Creek Formation, and volcanics of the Edith River Formation were prospected with carborne radiometric equipment. A comparatively high background count was recorded in the Edith River Volcanics, but no significant radiometric anomaly was found. A geological party prospected ten shear zones south east of the Edith Siding, including a cupriferous one, and a strongly fractured belt near the granite contact. No radiometric anomaly was found. Future prospecting should be directed towards major faults within the sediments.

The airborne scintillometer survey made in the latter half of 1952 revealed a number of anomalies in the Brodribb area. Detailed geological and geophysical work was carried out on this prospect during 1952 (Frankovich 1953) and some costeans were excavated by bulldozer. In 1953 diamond drilling and further geological and geophysical work was undertaken. During 1953, six diamond drill holes, with a total footage of 1583 feet, were drilled in the Brodribb area and were arranged to make an exhaustive test for the occurrence of a primary uranium deposit of importance in the area.

Abstract for initial submission, pending acceptance by convention technical program committee.