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.

No abstract available

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.

The presence of laterite described as high-silica bauxite at Mt. Roe on Cobourg Peninsula had been reported early in this century by H.Y.L. Brown, who submitted a specimen for analysis. In the absence of information about the mineralogical composition of the rock the chemical analysis alone affords a very incomplete description of the material. It was considered that the rock might be somewhat similar to the commercially valuable high-silica bauxite which occurs in the Netherlands East Indies and Malaya. At the request of the Australian Aluminium Production Commission the writer was instructed to examine the area in the vicinity of Mounts Roe and Bedwell, and to sample and report on any accessible bodies of apparently aluminous laterite. The locality, topography, and general geology of the area are briefly described. Accounts of the laterite occurrence at Mounts Roe, Bedwell, Kura, and Victoria are given. The mineralogical character of the laterite is described.

Legacy product - no abstract available

The principal deposits of bauxite occur on Bintan and adjacent islands which lie about 50 to 100 miles south-east from Singapore. This report is comprised of three extracts which have been drawn from papers made available to the writer by the Australian Government Commissioner for Malaya. The production figures, composition, and nature of the bauxite deposits are described in these extracts.

A spatial link between granitic intrusions and significant gold deposits has long been recognised in the Pine Creek, Tanami and Tennant Creek areas. However, both locally in these areas, and globally in similar systems, there have been protracted debates as to whether or not the spatially-related granitic intrusions are an essential ingredient in the formation of adjacent gold deposits. None-the-less, it is increasingly being accepted that the granite intrusions do play an important role and a new class of granite-related conceptual exploration models are now emerging. The two best known are Thermal Aureole Gold (TAG, Wall and Taylor, 1990) or Intrusion-Related Gold (IRG, Sillitoe and Thompson, 1998). Key ingredients in the TAG or IRG models are ilmenite- to magnetite-stable granitic intrusions and fluids to transport the metals from these granites to the sites of deposition. The depositional sites are rarely within the intrusion itself, and deposits can occur up to 5 kms from the granite boundary. Wall (in press) noted that this style of deposit is commonly located in the tops and roof zones of plutons, commonly in anticlinorial zones. Globally significant gold deposits that have been assessed as TAG or IRG types include Muruntau (>100 Moz @ 2-3 g/t), Fort Knox (>5.6 Moz), Pogo (5.7 Moz @ 17.8 g/t) Obuasi (>49 Moz) and Campbell-Red Lake (>25 Moz @15 g/t) (Wall, in press; Thompson and Newberry, 2000). It is the aim of this paper to benchmark the district to regional scale parameters of gold mineralisation in the Pine Creek, Tanami and Tennant Creek areas against these conceptual models and note any implications for exploration strategies. This review will consider some other NT provinces, but not the Arunta Province as insufficient details on the granites and sedimentary/ metamorphic sequences are currently available to confidently predict the location of potential IRG or TAG environments.

Deciphering element associations and affinities in the regolith is important for understanding mineral hosts and geological processes, such as sorting and pedogenesis. This has implications in environmental sciences in terms of distinguishing natural vs. anthropogenic element distributions and establishing realistic remediation targets. In mineral exploration, the strongest elements associations often drive distribution patterns in geochemical maps, yet these are not always the most useful ones to consider. In this contribution, we use National Geochemical Survey of Australia (NGSA) data to (1) identify the strongest controls of mineralogy (using major element total concentrations as a proxy) on trace metal distribution (using aqua regia Cu as an exemplar), and (2) remove the trend driven by the strongest major‒trace element association to calculate and map standardised residuals of the metals. In the coarse fraction (<2 mm) of NGSA top outlet sediments (0‒10 cm depth), which are similar to floodplain sediments, aqua regia Cu is most strongly correlated with total Fe of all the major total elements (r = 0.76 based on log‒transformed concentrations). Thus the aqua regia Cu map mostly shows regions where Fe‒oxyhydroxides in the regolith are abundant (or not) and naturally adsorb dissolved cationic metals from surrounding solutions. The predicted Cu map based purely on the total Fe concentrations and on the Fe‒Cu correlation is visually similar to the raw map. Only when calculating the standardised residuals between actual and predicted aqua regia Cu does additional information become apparent in the form of completely different geochemical patterns. These highlight areas where Cu that is not related to Fe (and therefore not in the form of Cu adsorbed onto Fe‒oxyhydroxides) is abundant (or not). For instance this Cu could be associated with silicate, carbonate or sulfate minerals. Thus this approach allows both environmental management and exploration strategies targeting different types of metal associations to be more effectively implemented, thereby reducing risk and cost. This Abstract & Poster were presented at the 2017 Goldschmidt Conference (https://goldschmidt.info/2017/)

The primary aim of the investigation was to determine the reserves and distribution of monazite in the deposits of heavy mineral sands along the East Coast. These deposits contain most of the known world reserves of zircon and rutile for which they are being exploited at various localities, mainly from North Stradbroke Island in Queensland to Ballina in New South Wales. Monazite forms little more than 0.5 per cent of the mixed concentrates, but can be recovered as a by-product from the separation of the other minerals. The monazite forms a source of supply of cerium and also of thorium. The thorium content of the monazite is determined on the basis of its radioactivity. This report gives an account of the field and laboratory work carried out. The results of the laboratory work, which included the separation and examination of minerals, the radiometric determination of quantities of monazite, and the investigation of the thoria content of monazite, are described in this report.

It has been fairly firmly established that the fineness of the gold in any ore deposit varies with the depth from the surface at which the deposit was formed and as a corollary to this, that it is dependent upon the temperature and pressure at the time of deposition. This relationship is such that, under certain conditions, the gold fineness, taken into consideration with other recognised criteria, furnishes a very sensitive and reliable guide to the relative temperature of ore formation, at least within the epithermal and the upper part of the mesothermal range. The definition, determination, relation to deposits, and application of gold fineness are discussed in this report.