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By Madgwick J. C

Bacterial leaching of museum grade chalcopyrite and chalcopyrite concentrates at low sorptive relative humidities (55-91 per cent rH) was demonstrated. Optimum release rates were 13 and 27 mg/gram/100 days copper (Cu++) at 91 per cent and 80 per cent rH and 12 and 33 mg/gram/100 days iron (Fe++) at 80 per cent and 73 per cent rH for concentrate and "pure" chalcopyrite respectively. The optimum copper release rates occurred between 73 per cent - 86 per cent rH and 30-40 mM acid concentrations. Bacterial copper leaching rates were some twenty times slower for emersed copper concentrates, at low relative humidity, compared with submerged cultures. Bacterial copper solubilization was almost quantitatively inhibited above 150 mM acid levels (< pHO.8).

Jan 1, 1984

The classic description of Project Finance as "the reliance by lenders on the cashflow of a project, supported by the assets of the project with no recourse to the project sponsor's corporate balance sheet" has, like most other terms in the finance industry, evolved through recent usage. The area now under most scrutiny is the sharing of risks between parties either most able to take them or prepared to accept payment for them. Creativity in, and flexibility of financing structures have enabled project lending to continue under a dramatically different economic outlook. The diminishing competitiveness of the Australian producers in a global market place of uncertain commodity prices has discouraged the advancement of many large scale resource projects. The majority of new project financings has been designed to assist the relatively small company promote and develop its first projects. New trends- are emerging in four areas: sources of capital; borrowing structure; financing instruments (securitisation); and risk underpinning. As project financing becomes more widely used, the range of interested financiers grows. New initiatives contribute to its development and evolution with a view to increase effectiveness to the sponsor of any new venture.

Jan 1, 1987

By Ormsby W, Peters M, Van Gils H, Kehprens P, De Boorder H

The northern margin of the Arunta Block is characterized by a metasedimentary and volcanic sequence of lower metamorphic grade than that of the central Arunta Block. Whereas the Harts Ranges have granulite to amphibolite metamor- phic grades, the northern margin only reached greenschist to lower amphibolite facies. Most of the high grade area of the central Arunta Block appears to be unprospective, but the lower grade marginal fringe contains most mineral pros- pects to name a few: Barrow Creek, Molyhill and the Jervois Mine. Numerous smaller prospects occur in this marginal zone. Four major lithostratigraphic units can be recognized in the Jervois Mine area: 1. Gneissic Suite consisting of granitic and rhyolitic gneisses which are characterized by a distinct intersection lineation. 2. Metasedimentary Suite of cordierite- biotite schists and chlorite-biotite schists. 3. Mine Sequence, consisting of spotted schists with andalusite and cordierite, quartz- sericite-feldspar schists with distinct rhyo- litic remnants and quartz-sericite-feldspar schists which contain the lode horizons:

Jan 1, 1984

The following is an outline of the main metallurgical process developments which have occurred at Port Pirie during more than 100 years of smelting. Emphasis is placed on those process developments which evolved from research and development at Port Pirie, rather than those based upon purchased or established technology and straightforward plant engineering. Most processes involved have undergone major change and improvement through the efforts of Port Pirie staff. A culture of metallurgical research and development evolved strongly during the years when G K Williams made such a great impact, and continued for half a century. This culture involved strong links with external research bodies, particularly universities. A near complete bibliography of these developments is provided, together with a listing of patents. Research and development by The Broken Hill Associated Smelters Pty Ltd commenced in 1918 at South Melbourne, and after transfer to Port Pirie in 1921, continued there until 1989. Three periods of highly successful innovation resulted ù that of G K Williams into the 1930s, the post-war period until about 1962 and the period with developments led by Denby H Ward from about 1970 to 1985.

Jan 1, 2000

Robe River Iron Associates (RRIA or Robe) is widely regarded as the worldÆs most cost-effective, consistent and reliable supplier of iron ore. It has been in operation since 1972 and globally is the fourth largest seaborne trader in iron ore exporting 25.5 million tonnes of -9.5 mm sinter fines and 4.5 million tonnes of pisolite lump (-31.5 +6.3 mm) during 1999. Robe is a joint venture that controls major iron ore resources in the Pilbara region of Western Australia. ItÆs participants are North Limited with an interest of 53 per cent (65 per cent including minority interests) and Japanese companies Mitsui (33 per cent), Nippon Steel Australia (10.5 per cent) and Sumitomo Metal Australia (3.5 per cent). Robe River Mining Co Pty Ltd manages the project which is a subsidiary of North Limited and Mitsui.

Jan 1, 2000

Early efforts to control the dust necessarily produced during dry crushing operations, took the form of venturis at loading chutes and other places where dust was most evident. These venturis discharged to the atmosphere and for obvious reasons were not very satisfactory.Attempts to collect the dust drawn off by the venturis, using dry cyclones, were not successful, the cyclones catching only the coarser particles. Further, no satisfactory method of continuously discharging the dust catchment was evolved. Water sprays were also used, and will be referred to later.In 1940, a single discharge fan of 3,000-4,000 cu. ft. per minute capacity, was installed to draw the dust-laden air from the Symons crushers and ·screening sections with their attendant conveyors. Suction was through two 15 in. ducts which branched off into 10 off-takes situated over the conveyers at points of discharge from crushers and screens.A dry cyclone was installed in front of the fan, which exhausted into a bag-house.The cyclone suffered from the defects of the smaller units mentioned earlier. When the collected dust reached a certain level in the cone, no more collection would take place until the cone was emptied. This objectionable feature was overcome by introducing a jet of water ahead of the cyclone. The water and dust collected overflowed a weir and were pumped to the mill.

Jan 1, 1948

By Burrell I

This paper describes recent developments at West Cliff Colliery in environmental monitoring, using a sophisticated computer controlled system. The operations involved in environmental monitoring are described and the equipment employed is detailed. It is anticipated that the monitoring system employed at West Cliff Colliery will be expanded to allow total and instantaneous monitoring of roadway environmental Conditions.

Jan 1, 1983

THIS SYMPOSIUM ON AUSTRALIAN BEACH SANDS IS MOST TIMELY; WHEN WE ARE APPROACHING PEAK PRODUCTION FROM THESE RESOURCES AND WHEN PRICES ARE GOOD, BUT THE RESOURCES CAN BE SEEN TO BE COMING TO AN END IN THE LIFETIME OF OUR YOUNGER COLLEAGUES - 20 TO 25 YEARS AS WE HEARD FROM ROY TOWNER TODAY. THE SPREAD OF PAPERS HAS BEEN 15 PERCENT EACH ON GEOLOGY AND THE MINERAL RESOURCES, WITH 25 PERCENT ON LAND USE AND ENVIRONMENTAL PROBLEMS. I AM PLEASED TO SEE 20 PERCENT HAS BEEN ON TREATMENT PROCESSES AND 25 PERCENT HAS BEEN CONCERNED WITH DOWNSTREAM USES. I SUSPECT THESE RATIOS ARE DUE IN PART TO THE WAY PAPERS WERE CALLED FOR, BUT THEY ALSO SUMMARISE CLOSELY THE BALANCE OF INTERESTS IN THE INDUSTRY. NOTE AGAIN; 30% CONCERNED WITH SUSTAIN -ING RESOURCES, BUT 25% WATCHING LAND USE AND IMPOSING CONTROLS; 20 % IMPROVING THE PRESENT PROCESSING, AND A HEALTHY 25% WITH AN INTEREST" IN WHAT HAPPENS TO THE MINERAL CONCENTRATES. I SHALL RETURN TO THIS FOURTH POINT AT THE END OF MY REMARKS. THE POSSIBILITY OF ADDITIONAL HEAVY MINERAL SANDS IN NEW AREAS WAS HINTED AT BY M.S. SHEPHERD (EG TERTIARY SHORELINES OF THE MURRAY BASIN). OLD FOSSIL SHORELINES, WELL REMOVED FROM PRESENT SHORES ARE AN IMPORTANT MINERAL SOURCE IN CHINA AND IT WOULD HAVE BEEN INTERESTING TO HEAR FROM THE SEVERAL COMPANIES EXPLORING IN THE MURRAY BASIN. I ALSO NOTICED THAT WHILST OUR MONAZITE

Jan 1, 1986

By Watson D. F

Armstrong's (1983) criticisms of PhiIip and Watson's (1982b) note on optimal drilling patterns are based on misinterpretation, supported by errors in geometry. Furthermore, Armstrong argues conceptually from the perspective of Matheronian geostatistics, as does also Rudenno (1983a, b). Thus, both authors embrace a global, probabiIistic method of assessing spatial data sets, an approach that must be contrasted strongly with local, deterministic interpolation methods. Some of the important assumptions of geostatistics are outlined and the non-unique nature of the method discussed. A probabilistic approach can be judged appropriate when exploration data are erratic, or known to be unreliable, or when extrapolation is desired. Where data are treated as exact, kriging can give the most biased result if tested against other interpolation methods. We reiterate our previous conclusion that the equilateral triangular grid is approximately 30 per cent more efficient (in terms of numbers of drill holes) compared with a square grid for the same maximum interpolation distance. This is simply due to the improved isotropy of sampling. New, locally-based, deterministic methods for computing ore reserves seem to be required.

Jan 1, 1984

By D R. Lueking

A technology involving separate unit processes for the generation and use of ferric ions for the oxidation of sulphidic minerals has been developed. The technology utilises a stand-alone automated bioreactor for ferric-ion generation (termed SAAB-FIG) and produces a low pH, ferric ion-rich leach liquor with a high oxidation potential. This leach liquor is then employed, in a separate unit process, to oxidise sulphidic minerals and regenerate ferrous iron that may subsequently be recycled to the bioreactor for the continual generation of ferric ions. The technique was successfully applied for the recovery of copper from chalcocite (Cu2S) and chalcopyrite (CuFeS2), as well as other ores and concentrates containing copper sulphide minerals. Coarse ore, ground ore and concentrates were treated with acidic solutions containing 8 to 12 (g/L) Fe(III) ions at a variety of temperatures. This process yielded over 50 per cent of the contained copper from both chalcopyrite and chalcocite samples. Maximum reaction rates and copper recoveries were found to be highly dependent upon temperature and pH and leach liquors containing bacterial cells displayed little difference in their leaching efficiency when compared to cell-free leach liquors.

Jan 1, 2000

Pyrite is one of the principal Au-bearing minerals in refractory gold ores. Significantly high Au concentrations of up to 5200 ppm are present in pyrite. Pyrite hosting high levels of Au is also enriched in As. Pyrite as an unwanted mineral ends up in wastes and constitutes one of the primary sources of As in the mining and metallurgical wastes. Arsenic can be readily released to the environment due to rapid oxidative dissolution of the host pyrite under atmospheric conditions. In order to determine the form and occurrence of arsenic in pyrite, micro-X-ray absorption fine-structure spectroscopy (XAFS) spectra were collected from a range of arsenical pyrite grains having different morphologies and a range of arsenic and gold concentrations. All the pyrite grains are characterised by the dominant edge aligned with As-1 valence state. In pyrite, arsenic atoms substitute for S atoms that are in six-fold coordination about each Fe atom. XAFS data suggest that As atoms occur in clusters within the pyrite structure. In addition to As-1, fine-grained, inclusion-rich and framboidal-type pyrite grains have a second As species at ~11 875 eV corresponding to As5+. This As5+ species in pyrite is highly variable and attributed to the oxidation of arsenic exposed on the surfaces of pyrite.

Jan 1, 2008

By Rolley P

In the course of reviewing grade control practices at the Marvel Loch gold mine in Western Australia in 1992, FSSI Consultants developed and implemented a novel approach to ore selection using a method to maximise financial return (the MP method*). The approach was based on improved grade control sampling and an ore selection method which directly incorporates both a measure of the uncertainty in knowing the true grade of selection units in the definition of ore, as well as the operating cost and revenue parameters of the mining operation. During the past four years, FSSI Consultants have evaluated and refined the use of this approach and have implemented customised variations of the MP method at seven gold mines and a gold-copper mine in Australia. The previous methods of ore selection at most of these operations were based mainly on polygonal - sectional methods of grade estimation. At all of the sites where grade control optimisation has been given a fair trial over several months of production, the use of the MP method has been consistently rewarding to the mining operations. The benefits include increased run of mine ore stockpiles and low-grade stockpiles and decreased fluctuation in the production grade. Most operations have also benefited from a consistent ability to improve production grade through high-grading of the increased ore production. The increase in ore production has the logical benefit of reducing stripping ratios, increasing mine profitability and mine life.

Jan 1, 1997

Shizuyuan deposit is a compound type of greisen and skarn associated' with W,mo,Sn,and BI mineralization. Tungsten-bearing skarns are located at the contacts between carbonate rocks and granitic stock. Ore-bearing greisens occur in the top of granite or superimpose on the skarn rocks. Although mineralization and alteration are heterogeneous,there are clear patterns in the preferred associations of minerals on all scales, and an orderly sequence can be distinguished. The sequence of mineralization Isom bhar. Gsesus-.contactròoctaard is characterized bòyVtia of L, a4[~!kient assemblages W(mo,~P),,,W,(,Mo,Sn,Bi),Sn (Bi), and Sn. Skarn formation is divided into an early sk.arnoid stage and a late metasomatic stage. The skarnoid stage formed grandite garnet and diopside pyroxene in the limestone. The iron content of garnets decreases significantly away from the granite, whereas pyroxenes maintain a relatively constant diopsitic composition. The metasomatic skarn stage is charac- terized by hydrous silicates. The mineral assemblages of. greisens are regularly distributed in space. The feldspar-quartz-fluoride was usually formed in-the deeper part, upwards giving way to muscovite-quartz, and topaz usually occurs in the uppermost part. The distribution, and miner- alogical relationships of alteration facies suggest that they formed as a result of the progressive reaction of an ascending hydrothermal solution with aluminum-nearing limestones an-d granitic rocks respectively. The ore elements were mobilized and deposited in association. with hydrosilicate alteration of skarns and greisens.

Jan 1, 1987

By S McKnight, S Hall

Much of the research regarding the use of bacteria for the oxidation of sulfide minerals has been conducted using pure bacterial strains or synthetic minerals, often under ideal conditions, which does not reflect the conditions commonly encountered in commercially operating plants. This has also led to much conjecture as to the exact mechanism by which bacteria are able to enhance sulfide oxidation and as to which species of bacterial microflora are the most dominant. Recent advances in 16S rNA sequencing has confirmed that many of the bacterial species once thought to dominate commercial oxidation circuits were simply more willing to grow under the culturing conditions used and may only play a minor role in the oxidation process (Rawlings, 2002). Consequently this research will look at bacterial oxidation under conditions more reflective of commercial operations, focusing on the presence of organic carbonaceous material within a refractory sulfide orebody to be sourced from the Fosterville deposit of Perseverance Corporation Limited.

Jan 1, 2004

By V S. T Ciminelli

This work aimed at evaluating the acid rock drainage (ARD) potential of five samples of a Brazilian gold sulfide mine in a decommissioning process. Three of the most traditional ARD prediction techniques, Standard Acid Base Accounting (Std ABA), Modified Acid Base Accounting (Modified ABA), as static methods, and humidity cells as a kinetic method were tested. Both the Std ABA and the Modified ABA results indicated an acid generation potential for some of the studied samples. In the other cases the results were inconclusive. The five samples were then submitted to humidity cell tests during 27 to 30 weeks. At the end of the period, the leachate pH was stabilised in a range from 3.4 - 4.1 (four samples) to 5 (one sample). The presence of relatively high levels of sulfate and dissolved metals was detected throughout the operation, specifically, Ni and Zn, and less frequently, As. These findings are discussed with the help of the samples mineralogy and Eh-pH diagrams. The results obtained in this investigation indicated potential environmental risks of this mining area. In this particular case, the kinetic tests were shown to be essential to the identification of the samples ARD potential.

Jan 1, 2003

By Reynolds JO

This contribution by. The Australasian Institute of Mining and Metallurgy has three main thrusts. First, an Institute (and industry) view on academia and the need for more entrepreneurship at top academic levels, second the need to lift our technological game, and third, professionalism and the perceived role of mineral industry education. While I will deal with each of these separately they are of course inter- related and can be brought together under the frequently used, but insufficiently practised title, "communications". First then, The Institute and industry view of academia. There are some academics in the audience and I imagine they may wish to reply to my remarks with an academic view of industry. That is not unreasonable. Like all human institutions, academic institutions vary in quality and characteristics. Some are successful and some less so. Some historically are well renowned. Others that were once successful schools have declined. Lesser known schools have grown into prominence. What is it that sets apart 'good' highly regarded schools from those that are not so well regarded? It comes down to one main ingredient - "leadership". The strong mining schools in the past 100 years have been strong because they have had outstanding and clearly identified leaders. Strong clearly identified leadership has always had rapport with, and the support of the industry. The two go hand- in-hand, each nourishing and supporting the Other.

Jan 1, 1986

By Warren R

Croesus Shaft is one of two operating shafts on North Kalgurli Mines Limited's Fimiston lease.At the cessation of gold mining in 1974, the workings at Croesus were allowed to flood. Large quantities of deslimed mill tailings used in filled stopes were washed into the shaft and surrounding drives, making re-access very difficult. The shaft has been desludged from the 9 level to the 15 level, and a loading pocket installed below the 14 level. A vacuum lift unit was installed underground to facilitate the removal of the slime and spillage.Stoping at Croesus was hampered by poor drainage, pumping, and shaft availability. These difficulties have been overcome by utilising an open stoping system for the relatively steep, narrow, high grade stopes. Open stoping has proved to be effective and economic.

Jan 1, 1985

Coal water mixture (CWM) is a mix of finely ground coal with water and a small amount of chemicals. It is a new way of transporting and handling coal. CWM can be transported, stored and burned like fuel oil in steam generating boilers. It also has some environmental advantages over both oil and bulk coal. A group comprising Ube Industries Limited, Nissho Iwai Corporation (both from Japan) and Coal & Allied Industries Limited has been working in Japan and Australia since 1987 on a joint feasibility study into the production, transport and marketing of CWM from Australia to Japan. The group has been studying the development of a large-scale CWM plant on Kooragang Island at the mouth of the Hunter River at Newcastle, NSW. The project concepts and engineering plans for the CWM plant are well advanced and other studies related to the project are continuing.

Jan 1, 1995

By Urabe T

In June 1989 a diving cruise of the French submersible Nautile has been carried out on the North Fiji basin spreading ridge. The objective of the cruise was the geological and geochemical study of the active spreading axis and associated hydrothermalism processes. This operation was the third cruise of the French-Japanese STARMER project following two cruises of the R/V Kaiyo in 1987 and 1988.INTRODUCTIONAfter the Seapso III cruise (Auzende et al., 1986, 1988a and b) of the R/V Jean Charcot in 1985, the objective of the Kaiyo 87 and 88 cruises was the complementary Seabeam mapping of the North Fiji Basin spreading axis between WS and 22'S and a systematic sampling (water and rocks) and deep towing (TV and photos) at about every ten milles along the axis.

Jan 1, 1990

By Isokangas T. A

With some two-thirds of the production exported, coal mining prac- tices of the last few years in Australia have been much influenced by the decline in the price received. It became essential to improve efficiency and rationalise operations. Trends in underground practice vary. On the one hand many additional longwalls have been installed and most recently the results achieved by them have shown a significant up-turn; this may be correlated more with increases in equipment capacity than with utilisation which has altered little during the past six years. Varied constraints remain affecting cur- rent and future longwall operations. On the other hand a number of mines have been closed whilst others have sought to improve results by various installations including miniwalls, shortwalls, and use of continuous haulage and mobile breaker line sup- ports. All mines continue to review working practices.

Jan 1, 1988