A diverse range of mineralisation, including porphyry and epithermal deposits, intrusion-related gold and other metal deposits, iron oxide-copper-gold (IOCG) deposits and orogenic gold deposits all have linkages to crustal growth and magmatic arcs. Furthermore, all of these deposit types are associated with fluids containing H2O, CO2 and NaCl in varying and differing proportions. In all cases, it can be argued that magmas are a key source of hydrothermal fluids for these types of mineral system, and that subduction processes are critical to controlling fluid chemistries, the metal-bearing capabilities of the fluids and depositional processes. The differences on typical/bulk fluid chemistries between deposit types can be explained in part by differences in the P-T conditions of fluid segregation from its magmatic source. The most significant control here is the pressure at which fluid forms from the magma as this has a strong effect on fluid CO2/H2O values. This is clearly exemplified by the rare occurrence of readily detectable CO2 in deep porphyry systems (Rusk et al., 2004). On the other hand, fluid Cl contents (which strongly influence its base metal carrying capacity) are very sensitive to the magma's bulk composition. However, only some subduction-related magmas are fertile, and the differences do not seem to be due solely to variations in effectiveness of depositional processes. So what controls the volatile content of the magmas? Isotopic and other evidence, in particular for S and Cl, shows (unsurprisingly) that the greater contents of these elements in arc magmas compared to other melts is due to contributions from subducted materials, although there may be additional, lower crustal sources of Cl. Variations in the budget of volatiles subducted may thus play a role in controlling the chemistry of magmas and associated hydrothermal fluids, but variations within individual arcs suggests that again this is not the entire story.

Metallogenic, geologic and isotopic data indicate secular changes in the character of VHMS deposits relate to changes in tectonic processes, tectonic cycles, and changes in the hydrosphere and atmosphere. The distribution of these deposits is episodic, with peaks at 2740-2680 Ma, 1910-1840 Ma, 510-460 Ma and 370-355 Ma that correspond to the assembly of Kenorland, Nuna, Gondwana and Pangea. Quiescent periods of VHMS formation correspond to periods of supercontinent stability. Large ranges in source 238U/204Pb that characterize VHMS deposits in the Archean and Proterozoic indicate early (Hadean to Paleoarchean) differentiation. A progressive decrease in - variability suggests homogenisation with time of these differentiated sources. Secular increases in the amount of lead and decreases in 100Zn/(Zn+Pb) relate to an increase in felsic-dominated sequences as hosts to deposits and an absolute increase in the abundance of lead in the crust with time. The increase in sulfate minerals in VHMS deposits from virtually absent in the Meso- to Neoarchean to relatively common in the Phanerozoic relates to oxidation of the hydrosphere. Total sulfur in the oceans increased, resulting in an increasingly important contribution of seawater sulfur to VHMS ore fluids with time. Most sulfur in Archean to Paleoproterozoic deposits was derived by leaching rocks below deposits, with little contribution from seawater, resulting in uniform, near-zero-permil values of 34Ssulfide. In contrast the more variable values of younger deposits reflect the increasing importance of seawater sulfur. Unlike Meso- to Neoarchean deposits, Paleoarchean deposits contain abundant barite, which is inferred to have been derived from photolytic decomposition of atmospheric SO2 and does not reflect overall oxidised oceans. Archean and Proterozoic seawater was more salty than Phanerozoic, particularly upper Phanerozoic, seawater. VHMS fluids ore fluids reflect this, also being saltier in Precambrian deposits.

The Tallandoon Antimony mine, known locally as Dalgliesh and Murphy's, is 2 miles northwesterly from Tallandoon store on the main Omeo Highway and just within the northeast boundary of the Parish of Tallandoon, County of Bogong. This record comprises a description of the general geology and geological report on the antimony deposits.

The Mont Murphy reefs occur in sedimentary rocks, which strike northwest and dip southwest at 45 degrees, about 31/44 mile north from an intrusive granite contact. The reefs, which strike north to northeast and dip steeply east, can be divided into three groups - the No. 1 reef, the No. 2 reef, and the Upper Mount Murphy group. Total positive plus probable ore on present mine exposures adds up to 1,132 tons, containing 18 tons tungstic oxide worth £9,900. Possible additional ore is about 2,500 tons with a tungstic oxide content of perhaps 41 tons. There is little prospect of capital invested being returned but the mine may pay operating costs if working expenses are kept to a minimum.

The Wilks Creek wolfram mine is situated in the parish of Steavenson, county of Anglesey in central Victoria. It is approximately 4 miles south from the small town of Marysville, a popular tourist resort, and 61 miles by road northeast from Melbourne. Underground and surface mapping was carried out on the 23rd and 24th November, 1943, with compass, tape and Abney level. This report comprises an overview of production history, general geology, economic geology and ore reserves.

"Greisen Lode" is the name given locally to the foot-wall section of a wider mineralised zone, which will be referred to as the Greisen Orebody in this report. Mining operations have been carried out by tributers in recent years on several portions of the orebody, namely, stoping from the Main Tunnel, stoping from an adit-crosscut driven from the No. 4 Gossan Bench, and some stoping operations from a level above the latter bench. During the past three months a level has been driven for 260 feet westwards from the Main Tunnel to prospect the orebody at this level and develop it for mining. Over the past few weeks a detailed geological examination of the orebody has been made and the area involved mapped on a scale of 20 feet to an inch by means of plane table and alidade.

The geology, ore reserves, development, costs, and surface operations of the Iron King mine are discussed in this report.

The present report gives an overview of the general geology and ore geology of the Blue Spec Mine. The main orebodies are described in some detail. General estimates of reserves and recommendations for future geological work are noted.

A geological report on the Alexander, Halley's Comet, and Manolis' Workings mines. The production, grade, geology, mineralisation, ore reserves, and prospecting of the mines are discussed. Accompanying geological plans are included.

A request was made for an estimation of the ore reserves indicated to date in the King Island Scheelite Mine, and for a drilling campaign to be drawn up to prove a total of fifteen years supply of ore at an annual rate of consumption of 200,000 tons. These two matters are dealt with in this report.