At Whites Deposit, Rum Jungle, chalcopyrite-uraninite ore has been intersected in a cross-cut at a depth of 100 ft., and sampling shows a grade of 1.5 per cent. U3O8 and 4.6 per cent. Cu. over a distance along the cross-cut of 34ft; material containing an average of 0.94 per cent. U3O8 and 2.97 per cent. Cu extends over 60 ft. Uranium mineralization is known to occur over a length of 200 ft, but the average width and grade over this distance is unknown. The ore replaces flatly pitching drag-folded beds and the width of ore along the strike is expected to vary considerably. At Dysons Prospect, about 30,000 tons of autunite-bearing ore, perhaps containing 0.25 per cent. U3O8, has been indicated by drilling. Browns Prospect is similar in many ways to Whites, but no payable ore has yet been intersected. In the district as a whole leaching of copper and uranium has been extensive and favourable areas are, in many cases, covered by soil. Structural conditions are such that non-outcropping ore is likely to be found. To-date, 3,300 ft. of drilling and approximately 700 ft. of underground prospecting have been carried out in the area and the results obtained are considered highly encouraging. Extensive drilling and underground development are warranted.

An outcrop of marmatite (zinc sulphide) has been located within the boundaries of E.P.L.26 held by New Guinea Goldfields Limited. The following notes describe the outcrop as discovered and certain recommendations are made to assist in the evaluation of the outcrop as a base-metal orebody. Other recommendations are made embracing other known occurrences of base-metal sulphides in the Territory of Papua and New Guinea.

In 1946 and 1947 the writer had excellent opportunities to study the effect of lateritisation in the course of geological reconnaissances in Northern Australia. From field evidence which has been collected on several aspects of lateritisation - origin, products and relationship to geomorphological processes - a detailed account of lateritisation in Australia can be given. Lateritisation and the occurrence of opal are discussed in this report.

The deposits of heavy mineral sands along the East Coast of Australia are being investigated primarily to determine their content of monazite. These deposits contain most of the known world reserves of zircon and rutile for which they are being exploited at various localities. Monazite, a phosphate of cerium, lanthanum, praseodymium and other rare earths, with thorium silicate, is utilised commercially as a source of cerium and of thorium. In this investigation, the thorium content on the monazite is being determined on the basis of its radioactivity. A principal deposit, and two smaller deposits, in the Fingal-Cudgen area were investigated. The geology of the area, methods of testing, and the results of the investigation are discussed in this report.

A number of Paleoproterozoic layered mafic-ultramafic intrusions in the central part of the Halls Creek Orogen of East Kimberley, Western Australia, have been explored for platinum-group elements (PGE), chromium, nickel, copper, cobalt and gold. Here we report on the halogen geochemistry of apatite and biotite in a number of these intrusions. Interstitial apatite is ubiquitous in these intrusions and, in most samples, tends to be relatively enriched in F- and OH-endmembers and relatively poor in Cl (< 20 mole %). Fluorapatite occurs in the more evolved igneous rocks and in marginal samples that apparently have been contaminated by metamorphic country rock. Cl/F ratios generally increase with bulk rock molar Mg/(Mg + Fe) ratios, as observed in other intrusions. Only a few samples show Cl-enrichment as high as that seen in the Stillwater and Bushveld complexes beneath the major stratabound PGE deposits. The most Cl-rich compositions observed occur in the upper part of the Springvale intrusion, where it is associated with troctolite, and in a single sample from the McIntosh intrusion. For the former intrusion, it is suggested that volatiles migrating out of the lower part of the mafic stratigraphy stabilized olivine at the expense of pyroxene. Associated biotite tends to be low in both Cl and F, containing no more than 10 mole % of these components. It is concluded that the East Kimberley intrusions contained a low to moderate volatile component that, during the combined processes of crystallization, degassing and fractionation of interstitial halogen-bearing minerals, was able to produce a late, mobile interstitial silicate liquid or volatile-rich fluid phase of variable Cl/F content that gave rise to most of the observed variations within any given intrusion. The exceptions include some marginal samples that appear to have been affected by country rocks, either during emplacement (assimilation) or during later metamorphism. The generally low Cl/F ratio of apatite, the lack of primary amphibole and the high background sulfur concentrations of the East Kimberley intrusions suggest that these magmas were relatively dry. The possible development of high-grade, PGE-enriched horizons by late-stage hydrothermal processes that could have mobilized significant amounts of the PGE and sulfur is considered to be of low potential.

A test survey was made with a Radore Equipment over three mineralised areas in Tasmanian. The investigations were made in January, 1955 for the purpose of comparing the performance of the Radore equipment with that of lower-frequency electromagnetic equipment previously used successfully over the same areas. The results show that although some very weak indications were recorded by the Radore equipment, it has not been possible to correlate these satisfactorily with the know mineralisation. Moreover, it is difficult to distinguish indications that may possibly be due to mineralisation from apparent indications that are undoubtedly due to irregularities in topography.

This report gives an overview of the bauxite resources of the Inverell district, New South Wales, including, in particular, those deposits held or examined by the Australian Aluminium Production Commission. A description of each deposit is given, which includes information on the geology of the area, grade of bauxite, and production figures. Figures are given for the proven reserves of economic bauxite in the district.

Legacy product - no abstract available

The potential for geochemical reactions to cause aquifer clogging or detrimental water quality changes was assessed for a managed aquifer recharge (MAR) target in the Darling River floodplain. The assessment used ambient groundwater quality from the target Calivil Formation aquifer, as well as from the shallow unconfined aquifers; Darling River source water quality; and mineralogy and geochemistry of sonic-cored aquifer samples. PHREEQC was used to examine the impact of mixing and interaction between these end-members. There is considerable variability in the redox state within the Calivil aquifer, with groundwater pe values ranging from -6 to 8. PHREEQC simulations using the median pe value of 3 resulted in super-saturation with respect to Fe(OH)3 . Hence, injection of an oxygenated source water into anoxic zones within the target aquifer can result in iron clogging due to precipitation of any source water dissolved iron and any Fe(II) oxidation in the sediments (in pyrite or displaced from exchange sites). The amount of Fe(II) within the storage zone available to be oxidised is unknown and may be limited given that Fe(III) oxides were present in the core material. The aquifer material contains species that may be released during MAR, including aluminium, arsenic, fluoride, iron, manganese, molybdenum, nickel, selenium and uranium. Injection of source water with elevated dissolved organic carbon (DOC) could enhance metal and metalloid release through reductive dissolution of iron oxides within the storage zone. The fate of any mobilised trace species would be dictated by storage zone redox conditions. Arsenic and molybdenum are likely to be adsorbed to any iron oxide surfaces under oxic conditions. Uranium and selenium are likely to reprecipitate in anoxic zones. This provides the opportunity for natural treatment within the storage zone to control mobilised trace metal species.

Raman spectroscopy has been used for the identification of both common and uncommon minerals in melt inclusions in Group-I kimberlites from Siberia, Canada, SW Greenland and South Africa. The melt inclusions all contained high abundances of alkali-Ca carbonates, with varying proportions of cations, and Na-Ca-Ba sulphates. However, no hydrated carbonates or sulphates were detected in melt inclusions from the Udachnaya-East kimberlite which is in agreement with its dry matrix mineralogy. In contrast, the melt inclusions in kimberlites from Canada, South Africa and SW Greenland were found to contain bassanite, pirssonite, and hydromagnesite suggesting that greater amounts of water were present in their residual magmas. This suggests that enrichment in alkali carbonates and sulphates is widespread across a range of Group-I kimberlites and implies that they commonly have an alkali-, and sulphur-rich residual kimberlite melt.