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By C G. Ryan, T P. Mernagh, S R. Hunns, R A. Both, R R. Large, J B. Gemmell

 The Hellyer and Mt. Chalmers deposits are mound-style volcanic-hosted massive sulphide (VHMS) deposits in Australia. Textural, petrographic and microthennometric investigations of fluid inclusions in the Hellyer stringer system indicate that Type I, primary, liquid-vapour inclusions are 10 - 15 J.UIl in size, and yield homogenisation temperatures of 170 - 220¦C in early 2A veins, 165 - 322¦C in main-stage 2B veins and 190 - 256¦C in late-stage 2C veins. These data suggest a waxing and waning thermal history. However, the average salinity remained between 8 - 11 NaCl equiv. wt % in all Stage 2 veins. At Mt Chalmers, Type I inclusions up to 20 urn are found in quartz from the mineralised zone, and these inclusions yielded homogenisation temperatures of 160 - 268¦C and salinities of 5 - 8 NaCl equiv. wt %. Laser Raman spectroscopic (LRS) analysis indicates the presence of CO2 (<1 mole %) in the Hellyer and Mt. Chalmers VHMS systems. Semi-quantitative SEM/WDS microprobe analyses of fluid inclusion decrepitates indicate that the Hellyer and Mt Chalmers ore fluids were enriched in potassium and calcium but depleted in magnesium relative to seawater. PIXE microanalysis of fluid inclusions in quartz also indicates a significant base metal concentration in these fluids. Cation composition and higher salinities relative to seawater suggest that recycled seawater alone cannot be the sole source of the ore fluids. High base metal content and the presence of CO2 in the fluid inclusions imply that magmatic input of ore metals during seawater leaching of the footwall volcanic pile is a distinct possibility.

Jan 1, 1995

A rotating disc geometry was used to provide a uniformly accessible surface for a kinetic study of copper cementation with zinc in sulphate solution. For copper concentrations of the order of 10 p.p.m., a porous, adherent deposit is formed on the zinc surface and this has a significant influence on the reaction rate. When the specific mass of deposit is less than about O· 35 mg/cm2 the surface may be considered as smooth and the rate is described by simple convective counter diffusion of zinc and copper ions through a laminar diffusion boundary layer to the deposit-solution interface. In the presence of additional deposit, the diffusional mass transfer rate is increased by increased surface roughness.The rate under these conditions is first order, with the degree of enhancement independent of further increases in the specific deposit mass. The enhancement in rateis, however, directly related to the initial mass flux and the species involved in the reaction.Preliminary work showed the same mechanism to apply to cementation from chloride solution, solutions of high zinc concentration, and cementation of copper with iron..

Jan 1, 1970

This paper considers three aspects of cemented fill practice and research in Mount Isa. Firstly, an account is given of the use of Portland cemented hydraulic fill, considering mainly the role and specifications of the fill used but including û brief description of fill preparation and placement. Data resulting from a Portland cemented hydraulic fill sampling, curing and testing campaign covering about 18 months of operating practice are presented, analysed and discussed. These yield information indicating the mode of operation of a fully-automated fill preparation station, as well as a means of comparing field and laboratory strength results. A technique with potential for use as a fill quality control without actual strength testing is also described. Results of a fill research program conducted by the author in Mount Isa since early 1968 are presented, involving both Portland cemented hydraulic fill and alternative, cheaper, additives for cementing hydraulic fill.

Jan 1, 1971

LAKE MARGARET is situate high up on the West Coast Range of Tasmania, and lies in a roughly triangular valley formed by the ridge of Mount Sedgwick on the south, the ridge formed by Mounts Geikie and Tyndal on the west, amid a ridge connecting Mounts Geikie and Sedgwick on the east. Any description of this hydroelectric installation, however brief, naturally divides itself into the following sections:1. STORAGE BASIN, &c. 2. DAM. 3. PIPE LINES. 4. POWER STATION. 5. TRANSMISSION LINES. 6. SUBSTATION 7. VARIOUS WORKS utilizing the power.The Storage Basin used is the natural lake itself, which has a maximum length of 110 chains, a maximum width of 40 chains, and a mean arelj. of 300 acres. The water-level of the lake, which has been maintained by a natural dam, is 2143 ft. above sea-level. The approximate catchment area at present appropriated is 7 sq. miles, and the rainfall, on the average, about 144 in. per annum. It is possible to increase this catchment area by suitable races, &c. Dam.-The dam constructed is of very small dimensions, and is not a storage dam in the usual sense of the term. The natural storage ot-the lake itself was used by means of a channel cut through the natural dam and thence to the mouth of the lake, the lake level being thus temporarily lowered while the outlet pipes, screens, &c., were placed in position, and the channel was then closed again with a concrete wall in which the pipes and screens are set. This channel was cut partly through rock and partly through sand and conglomerate boulders for a total...

Jan 1, 1915

The ~2500 km long Kermadec-Tonga arc northeast ofNew Zealand is the longest continuous intraoceanic arc in the world. At least 94 volcanic centres along the arc are submarine, most (87 per cent) within the Kermadec arc (de Ronde et al, 2003a). Volcanic rocks range from basalt to rhyodacite with trace element and isotopic data indicating significant magma source heterogeneity both along and across the arc.   The entire ~1300 km of the Kermadec arc has now been surveyed for hydrothermal emissions (de Ronde et al, 2004). First-stage surveys utilised surface vessels. In February 1996, the first sulfide samples from the southern Kermadec arc were dredged from the Brothers and Rumble II West caldera volcanoes (R/V Tangaroa cruise TAN96/03; Wright et al, 1998; de Ronde et al, 2003b). In September 1998, low-temperature, diffuse venting was discovered at Monowai, Rumble III and Clark volcanoes, and high-temperature, black smoker venting was found within Brothers caldera (R/V Sonne cruise SO-135; Stoffers et al, 1999). The NZAPLUME cruise of March 1999 surveyed 13 volcanic centres (each mainly comprised of single, large volcanoes) of the southern Kermadec arc and documented hydrothermal emissions above seven of them (de Ronde et al, 2001; Baker et al, 2003; Massoth et al, 2003). In July 2001, additional mineralised and hydrothermally altered samples were dredged from Brothers volcano (R/V Tangaroa cruise TAN01/07). The NZAPLUME II cruise of May 2002 confirmed venting was still occurring at all the known hydrothermal sites, and that ten active vent sites occurred along the mid-part of the arc, between Brothers and Raoul Island (de Ronde et al, 2002). In September-October 2004, NZAPLUME III surveyed the northern-most part of the Kermadec arc where another nine volcanic centres are hydrothermally active.   Second-stage exploration of the Kermadec arc hydrothermal systems utilised deep submergence vehicles. In October-November 2004, the Japanese submersible Shinkai 6500 made four dives on Brothers. Samples recovered include vent fluids, chimneys, altered rocks and various animals and microbes. In April-May 2005, a more extensive expedition using the American submersible Pisces V made 23 dives on nine different volcanic centres, eight of them for the first time.   Extensive plume surveys show Brothers volcano is host to the most hydrothermally active sites of all those known along the Kermadec arc. In total, nine dives have been made on Brothers, six on the NW caldera site and three on the cone site. The NW caldera vent site is a long-term hydrothermal system that is today dominated by evolved seawater but has had episodic injections of magmatic fluid. The cone site is a nascent magmatic-hydrothermal system where crack zones localise upwelling acidic waters (de Ronde et al, 2005). A SE caldera site represents the main upflow of a relatively well-established magmatic-hydrothermal system on the seafloor where sulfide-rich chimneys are extant. Each of these different vent sites represent diverse parts of an evolving hydrothermal system, any one of which may be typical of submarine volcanic arcs.

Jan 1, 2005

Results obtained from small scale tests using Australian tin concentrates indicate that metallic tin containing less than 0·1 per cent iron can be recovered by a two-stage process using hydrogen and make-up chlorine. In the first stage the concentrate is ground,. pelletized, roasted, and reacted at 650°C with HCI and H2 to volatilize the tin as SnOI2. The volatilization reaction is conducted with cocurrent gas and solids flow because it was found that the use of cocurrent flow yielded a solids residue substantially free from FeCI2. The second stage uses a technique termed "reflux reduction" during which the SnOl2 produced by volatilization is reduced by hydrogen to form tin and a gas containing HCI and H2 of sufficiently high HCI tenor for recycle to the volatilization stage. The elimination of tin ranged from 98+ to 99·7+ per cent of the tin from concentrates containing 5 to 50 per cent tin, respectively. The process should be capable of continuous operation, and a tentative calculation has shown ,that a treatment rate of 12,000 tonnes of tin concentrate per year could be obtained in a volatilization reactor 1·1 m in diameter and 6·1 m high. The process may have particular application to finely divided concentrates containing less than 20 per cent tin.

Jan 1, 1974

Performance of Dry Separation Processes in Cenospheres Recovery from Coal Fly Ash

Sep 13, 2010

By Cooper R. J

The essential features of the zinc concentrate roasting installation at the Risdon Works by the Electrolytic Zinc Company of Australasia Ltd. are given.The problem of maintenance of ignition in down-draught zinc concentrate flash roasters is discussed, and a solution offered.A successful and economical method of using by-product oxygen for raising the roasting efficiency of hearth roasters is described. Three methods of utilizing oxygen for the same purpose in flash roasting are detailed, and their relative merit, considered.INTRODUCTIONThe zinc sulphide concentrate used at the Risdon Works is roasted autogenously for removal of sulphur in two hearth roasters, and four flash roasters. The hearth roasters are of modified Skinner type with eleven hearths. They were designed, and are used, for roasting mixtures of relatively low sulphide content. Their design and operation have been described elsewhere (Forster, 1949).The flash roasters are down-draughted furnaces with cross-section and rabbling equipment based on the hearth roaster design, and the process is similar to that developed by the Consolidated Mining and Smelting Company of Canada Ltd. (Cominco) at Trail, B.C. (Stimmel, Hannay, and McBean, 1936).These furnaces are 20 ft. in diameter. They have three drying hearths through which hot gas is drawn from the combustion chamber by the burner fan. The combustion chamber is 2'1 ft. high above the collecting hearth (27 ft. in No. 4 unit), and the discharge hearth below it is 6 ft. high, so that a large gas offtake is possible. Four rabble arms for each hearth are carried on a central column. Dried, ground concentrate, and the air for roasting it, are fed to a burner...

Jan 1, 1958

Flotation Research on Cassiterite of Tailings

Sep 13, 2010

When the first rush of miners took place on the Molyneux River, in the Dunstan Gorge, the gold was won by means of cradling the gravel, which was shovelled from the various beaches and crevices in the rock-bound sides of the river.The above method of winning the gold was only practicable when the beaches were not covered with water, hence the work was usually carried on during the winter months, the ordinary level of the river during spring and summer months being some ten or twelve feet above winter level. The melting of the spow in the Lakes water-shed being responsible for the high summer level of the river.As the available beaches were worked out, other methods of winning the gold were proposed and worked with more or less successful results the first advance being to work the bed of the river by means of a spoon dredge. The spoon was made with a round lip or ring of iron, having a steel cutting edge on one half of the circumference, at the opposite side a socket being forged to take a long spar or boom, which was securely fitted thereto. At intervals round the hoop, half-inch holes were bored to enable. a bullock-hide bag to be laced on to same. The spoon was worked from a pontoon which carried a crab winch, tackles and the necessary washing appliances to treat the washdirt lifted. In starting to dredge, a tackle was attached to near the upper end of the boom, and a line or chain was carried over a cat head from the crab winch...

Jan 1, 1901

Iron Ore - Mineral Processing Overview Several years of iron ore price increases, coupled with a period of strong global demand for raw materials, presented iron and steel producers with unprecedented costs and difficulty procuring the demanded high quantities of iron ore. These conditions spurred many companies to investigate new ore bodies and also reassess past decisions (such as divestment of captive iron ore mines that ensured dedicated supply or a move to reliance on the 'spot market' instead of long term contracts with suppliers) and revisit alternative sources of iron units, including low grade deposits, tailings reprocessing, Ti-rich ores, and iron sands. To properly upgrade these iron sources requires a complete battery of mineral processing techniques. Within different regions around the world, operations and technology have developed to specifically beneficiate the local ore bodies. This paper attempts to bring these different general processing techniques together to allow insight into various common and proven methods of iron ore beneficiation. This paper further explores the current trend to develop global iron ore reserves, and discusses the methods to beneficiate and successfully reduce and smelt iron ore using Outotec's physical separation, direct reduction and smelting technologies for final production of pig iron and slag. Use of these various technologies may allow treatment of what was typically considered a tailings stream into a profitable product.

Sep 13, 2010

By McLeod RL

The Tolukuma gold-silver prospect is located approximately 100km N of Port Moresby in the Central Province of Papua New Guinea (PNG). Epithermal "adularia-sericite" style mineralisation crops out over 1200m within an en echelon quartz veined zone 1 to lOm wide. At a 4g/t cut-off grade, a geological resource of approximately 1.47Mt @ 13.77g/t Au is indicated from 38 diamond drill holes completed since discovery by Newmont Pty Ltd in September 1986. At a regional scale, Tolukuma miner- alisation appears localised in a dilatant zone at the intersection of a 1150 magnetic structure, and the western margin of a N-S trending graben which is filled by a Pliocene volcanic complex contemporaneous with the Mt Davidson Volcanics 30km to the W. A l0km diameter circular Landsat feature, which may reflect magma emplacement at depth, occurs immediately N of Tolukuma and nearby mineralisation. Mineralisation at Tolukuma occurs in sub-vertical quartz veins at, or adjacent to the faulted contact between Pliocene basic and intermediate volcanics/intrusives, and quartz mica schists and phyllites of the Cretaceous Kagi Metamorphics. Most veins display evidence of multiple episodes of brecciation and textures indicative of cyclic boiling, including crustiform rhythmic banding and quartz pseudomorphs after platy calcite.

Jan 1, 1991

An Ammonia Leaching-Solvent Extraction-Electrowinning-Flotation Process for Copper Oxidised Ore Treatment

Sep 13, 2010

Sustainable development is a critical discussion topic in the mining industry today. The topic is necessarily broad and complex, covering an entire spectrum of related areas, from geology to end-use products. The objective of this keynote address is to focus on the chemicals and chemistry aspects - especially research and technology transfer - in sustainable mineral processing. Chemicals came to play a critical role in mineral processing during the last century, and they will play an equally vital role in confronting the sustainability challenges of the 21st century, particularly in the areas of greener chemicals, water efficiency and water resource management; waste reduction and remediation; minimising environmental impact, safety and health risks (meeting and exceeding the requirements of regulations); energy efficiency; and converting mineral resources into reserves. This keynote address argues that the current research framework is no longer adequate to serve the goals of sustainable mineral processing. The problems studied are often too narrowly defined or irrelevant, while the research efforts are fragmented and the methods and approach employed are often too reductionistic to produce useful knowledge. A new framework for research is needed. This address further argues that a new framework based on a holistic or systems approach can best tackle the challenges of sustainable mineral processing. Central tenets of this approach include a recognition that, in complex systems, the behaviour of the whole system is more than the sum of the individual contributions, and that interactions occur in real time, often in subtle and complex ways. The focus is thus on the behaviour of the whole system. Indeed, a comprehensive understanding of the system through large-scale measurements should precede a study of parts or of idealised models of the complex system. The result will be a sound knowledgebase, better solutions to the challenges of sustainable development, and improved technology transfer. Developing such a framework will pose a formidable challenge, requiring significant time and effort as well as a confluence of diverse specialties and strategic collaboration. Fortunately, recent developments in the context of reagent optimisation provide us with a prototype of a holistic approach. We can also draw upon methodological innovations in the biological sciences, where the critical need for a systems approach is well recognised and significant advances have been made.

Sep 13, 2010

Fire-clay blocks lining the combustion chambers of zinc concentrate flash-roasting, furnaces operating at 1,000-1,200° C. have suffered moderately rapid deterioration due to slagging. The attack is accentuated by high temperatures, and is probably caused by lead oxide volatilized from the roasted concentrate.Resistance of refractories to attack increased with increasing alumina content from 30 to 45 per. cent but at 90 per cent alumina spalling was troublesome. Magnesite bricks were'subject to some spalling, but some types may lie satisfactory. Chrome and chrome-magnesite bricks spalled seriously.Material thought to be suitable for use as a monolithic lining slagged badly and an alternative may be tested.INTRODUCTIONThe Electrolytic Zinc Company of Australasia Ltd. uses two multi-hearth furnaces and four flash or suspension roasting furnaces for the roasting .of zinc concentrates at its Risdon Works. The hearth roasting plant has been described previously by Forster (1949).A brief descriptioI1 of the first three flash roasters was given by Gordon and Forster (1955). A fourth flash roasting furnace began operation early in 1957. This furnace is somewhat larger than the earlier furnaces, and the designed capacity is also higher, auxiliary equipment being altered to suit. An important structural difference between the older furnaces and the fourth flash roaster is that the walls of the combustion chamber of the new furnace are lined with high alumina fire-bricks instead of fire-clay blocks. Thischange was made because the fire-clay blocks in the older flash roasters had shown s-evere wastage due to slagging by lead derived from the concentrate.

Jan 1, 1959

By Hart G. H

In tectonically disturbed zones within coal seams, decreases in the amount of kaolinite in the cellular structure of inertiniterich coal are accompanied by increasing kaolinite contents in fractures within the coal and/or rocks of immediately overlying horizons. This is due to fracturing of the inertinite microstructure by tectonic disturbance and remobilization and redistribution of free, fine-grained material (kaolinite and/or inertodetrinite.) Ascending waters are believed to transport the kaolinite in suspension, and redeposit it in the fractures and pores in the overlying horizons. This removal of material from the inertinite-rich coal leads to an increase in porosity (higher free gas storage), a presumed reduction in coal strength and an apparent increased proneness to instantaneous outbursts of coal and gas.

Jan 1, 1983

A slag-metal equilibrium study of the system SnO-FeO-(Si02+Al2O3)/Sn-Fe was carried out at 1250°C. The distribution coefficient, k =(Sn/Fe)metal X (Fe/Sn)slag was found to range from 246 for an iron contentof 0·53 per cenrt in the metal to 82 for an iron content of 6·4 per cent. The value of the ratio ?SnO/?FeO was calculated and found to be approximately a function of per cent SnO in slag alone in the region (Si02+Al2O3)/ FeO = 0·4 to 1·2. Comparison with other published work suggests that the addition of CaO to slags having (SiO2+Al203)/FeO ratios of about 1·1 raises the value of ?SnO/?FeO...

Jan 1, 1974

The area around Big Bell was actively explored and sporadically mined for gold from 1904 onwards. The lease was named Big Bell in 1913. The property became established as a major mining centre with the development of the Big Bell underground mine in 1936. Mining operations commenced in late 1937 and ceased in January 1955, after milling 5.56 million tonnes of ore and producing nearly 21 tonnes of gold. In 1969 Australian Consolidated Minerals Ltd (A.C.M.) acquired the deposit then explored it alone and in joint venture until the current joint venture agreement with a subsidiary of Placer Pacific Limited (PPL) was negotiated in 1984. Following exploration and evaluation of near surface mineralisation, and a reassessment of the remnant pillars underground, the concept of a large open pit in conjunction with an underground mine evolved. The feasibility study was completed in October 1987, and the decision to go ahead was formally announced on 2nd December 1987. Placer Dome Technical Services Ltd were contracted to be the Project Managers, commencing construction on site early in January 1988 and handing the plant over to the operators 13 months later. The capital cost of the project at handover was estimated to be $133 million. The operating team commenced pre-production stripping of the open pit on 1st May 1988. By 31st January 1989 almost 16.0 million tonnes had been stripped and 350,000 tonnes of ore stockpiled.

Jan 1, 1989

By P Steinier

Most operations, when considering their comminution circuit, are primarily concerned with achieving the desired particle size distribution to obtain adequate liberation for the separation process, at minimum cost. Invariably, the effect the grinding media has on the subsequent separation process (ie flotation, leaching) is not taken into account when selecting the media. This choice is driven by cost rather than metallurgical outcomes. Maximising valuable mineral recovery, with optimum selectivity against gangue minerals, is about good particle preparation. And, particle preparation is strongly related to achieving adequate mineral liberation with the correct pulp chemical conditions. However, the pulp chemistry of a system is largely ignored and relies heavily on pH control and the addition of appropriate reagents (collectors, frothers, activators, depressants). The changes effected by the addition of the various reagents are obtained through conditioning the ground pulp prior to or during the concentration stage, subsequent to grinding. Frequently, reagents are added during grinding with good effect, but the impact of the grinding media on down stream processing is usually overlooked. A number of case studies examining the effect of grinding media on pulp chemistry and subsequent flotation performance were completed on several different sulfide mineral systems (for example, lead/zinc, copper, refractory gold). The evidence suggests that a change in grinding media type from forged to high chrome (ie conditioning the pulp during grinding) resulted in a shift in pulp Eh to less reducing conditions, an increase in the dissolved oxygen content of the pulp and a reduction in the iron species present. The changes have a positive impact on flotation behaviour. The results of the case studies are discussed.

Jan 1, 2004

Between February and August of 1986, Dr Alfred Petrick visited New Zealand sponsored under a Fulbright grant administered by the New Zealand-United States Educational Foundation. The grant supported a research project completed by Dr Petrick having as an objective, the preparation of a preliminary economic evaluation of the mining of six Otago lignite deposits as a source of energy for steam power generation or in liquid fuels. The research is limited to consideration of preliminary geological and engineering data on the six deposits and to the time constraints of the Fulbright visit. This paper is a summary of the final Fulbright report. The complete report including the listings of the computer programs is available from the Otago School of Mines.

Jan 1, 1986