Dr Andy Barnicoat's presentation at the China Mining Conference 2012 in Tianjin.

Increases in atmospheric CO¬2 cause the oceanic surface water to continuously acidify, which has multiple and profound impacts on coastal and continental shelf environments. Here we present the carbonate mineral composition in surface sediments from a range of continental shelf seabed environments and their current and predicted stability under ocean acidifying conditions. Samples come from the following four tropical Australian regions. 1. Capricorn Reef (southern end of the Great Barrier Reef). 2. The Great Barrier Reef Lagoon. 3. Torres Strait. 4. The eastern Joseph Bonaparte Gulf. Outside of the near-shore zone, these regions typically have a carbonate content in surface sediments of 80 wt% or more. The abundance of high magnesium-calcites (HMC) dominates over aragonite (Arag) and low magnesium-calcite (LMC) and makes up between 36 and 50% of all carbonate. HMC is significantly more soluble than Arag and LMC and the solubility of HMC positively correlates with its magnesium concentration. Using the solubility data by Plummer and Mackenzie (1974) (1), 96% of HMC in the four regions is presently in thermodynamic equilibrium or slightly supersaturated relative to global mean tropical sea surface water. When the modelled saturation state for aragonite in equatorial areas for this century (2) is converted into HMC saturation state curves, HMC is predicted to become undersaturated in the four regions between 2040 to 2080 AD with typical HMC decline rates between 2 and 5% per year. The range of respective estimated carbonate dissolution rates is expected to exceed current continental shelf carbonate accumulation rates leading to net dissolution of carbonate during the period of HMC decline. In a geological context, the decline in HMC is a global event in tropical continental shelf environments triggered by reaching below-equilibrium conditions. The characteristic change in carbonate mineral composition in continental shelf sediments will serve as a geological marker for the proposed Anthropocene Epoch.

This report outlines the headings under which mineral statistics might be collected, and the information that is required from metal and mineral producers. Attached are lists of metals and mineral products under the appropriate classes.

The Bulong vermiculite deposit, situated 20 miles east of Kalgoorlie was discussed with members of the West Australian Mines Inspection Branch. The geology, quality, and production potential of the deposit are discussed in this report.

This report comprises notes concerning the situation, occurrence, analysis, and production of dolomite at Cow Flat.

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.

In the Northern Territory laterites are formed in situ as: (i) an illuvial soil horizon; and (ii) a chemical lake laterite deposit. The end product of extensive weathering processes of certain favourable beds is considered by some to be a true mature laterite, whereas others believe it is merely a duricrust. The denudation of laterite and transportation, deposition and cementation of the fragments with other rock fragments result in a detrital laterite deposit. Water-rounded rock fragments in the detrital laterites are readily coated and cemented with iron oxides and resemble the pisolites in the ferruginous zone of the lateritic profile. This similarity results in an exaggeration of the true extent of laterization. The similarity in environmental conditions between the process of precipitation of uranium minerals and laterization is discussed. True mature and detrital laterites are illustrated by photographs.

The mineral resources sector plays a vital role in Australia’s ongoing economic prosperity. The sector dominates the nation’s export earnings, provides substantial direct and indirect employment and investment in regional and indigenous communities, supports downstream and service industries, and delivers essential revenue to governments.

The collection supports the compilation of national mineral resource and production statistics, and mineral prospectivity analysis. The collection includes the OZMIN database (Australian mineral deposit descriptions including geological, resource and production data); the MINLOC database (mineral occurrence locations sourced from Geoscience Australia and state and territory geological surveys); supporting GIS datasets (eg,mineral prospectivity datasets, ports, power stations); maps and reports.

Two samples of diatomite were recently received from Broken Hill Pty. Co. Limited for microscopic examination. They were from Nettle Creek, 9 miles north-east of Mt. Garnet and near Innot Hot Springs. The results of the microscopic examination are given in this report.