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By Govett G. J S, Currie D. A, Cohen D. R

Analysis of mechanical size fractions of soils around the Paddington deposit (W.A.) and the Charters Towers Goldfields (Queensland) shows a bimodal gold distribution, with enrichment in the coarsest and finest fractions; this is probably a common feature of soils in arid terrains. To establish the true distribution of Au within the soil fractions, the effect of bulk Au content and percent weight variations in size fractions can be reduced by a normali- zing procedure. The greatest extent of lateral dispersion of Au recorded in the -125 ¦m fraction at Paddington and the -63 ¦m in the Charters Towers area as compared to the coarser fractions, and increas- ed levels of sample representivity in the finer fractions, favours their use in exploration. If orientation studies indicate the preferen- tial use of coarse or intermediate fractions, only wet sieving can quantitatively dis- aggregate the clays and remove finer contamina- ting material. The collection of extremely fine fractions such as the -63 ¦m is also accelerated by wet sieving. The additional costs of wet sieving may be offset by better interpretation of results through increased analytical sample representivity, anomaly contrast and continuity.

Jan 1, 1988

Every step on the path from the mine to the smelter invites a comparison between material inputs on one side and outputs plus accumulation on the other. Or put simply, between what you think you have produced with what you find you have at hand. The discrepancy between these sets of comparisons is the error. Following that error in a systematic and objective manner is a way to improve the mineÆs measurement systems, that in turn leads to more accurate accounting for ores, metals and concentrates. Because the control of production is so tightly coupled with the accounting of materials, any lasting improvements in materials accounting will benefit the predictions of materials movements and quality. This translates to more reliable planning and scheduling in stockpile management, logistics, shipping and marketing. The statistical tools described are direct adaptations from the long-standing methods used to maintain the quality of manufactured product in the discrete parts industries. Their use in the process industries, of which mining is one, requires some care owing to the continuous nature of ore extraction and its variable properties. The tools can be used for problem diagnostics and as early warning systems. In common practice many professional staff, in attempting to get a perfect reconciliation between expected and observed results, try to explain away the error or bury it completely. The methodology advocated here requires a different mindset because the error must be given pre-eminence for lasting improvement to be realised.

Jan 1, 2002

Interactive data exploration is essential for visualising grade distribution and geological controls on orbodies. Quick and appropriate computer techniques for making daily 'value adding' decisions include routine imaging of numerical data suc

Jan 1, 1998

By Kershaw M. G

At the Risdon plant of the Electrolytic Zinc Company of Australasia Limited, impurities toxic to the electrolytic production of zinc metal, notably arsenic and antimony, have traditionally been coprecipitated when precipitating iron as ferric hydroxide. With the development of a new lead/zinc mine at Elura, New South Wales, it was anticipated that the concentration of impurities, particularly arsenic, in the zinc sulphide concentrates treated at Risdon would increase. This suggested that an increase in the capacity of the iron purification step in the Risdon plant would be required to cope with the higher input of these impurities.Laboratory investigations showed that the additional capacity would be achieved, either by a large increase in the amount of iron used as the "collector" in the process, or by a two-stage process. The latter approach was preferred as a increase in the amount of iron precipitated would lead to much higher operating costs and overloading of the existing equipment.In the two stage procedure, acidic iron bearing solution is added to solution feeding the first stage and most of the arsenic removed from solution when iron is precipitated from solution by neutralisation with limestone. Mter separation of the precipitated solids, acidic iron bearing solution is added to the solution, and remaining arsenic removed almost completely following neutralisation by limestone.This paper describes the laboratory and pilot plant results and the plant modifications required. Abrief account is also given of the operator training and acceptance in the use of the digital control facilities installed in the new plant.The new plant is working well and good solution purity is being maintained despite a substantial increase in the concentration of impurities in the raw materials.

Jan 1, 1990

By A Logan, B Cuthbert

Brown and Chitombo (2007) indicated that during the last two decades, the international mining industry has been using mainly mass mining methods to extract safely and economically some of the important commodities such as copper, diamonds, gold, iron and nickel. Mass mining may be implemented either on the surface through large open pits or underground using mining methods such as sublevel, block and panel caving. Developments in the last ten years have demonstrated that caving methods can be applied successfully in strong orebodies at greater depths and in increasingly challenging geotechnical environments for which more traditional mining methods would be unsuitable, unsafe and/or uneconomic. These underground mass mining challenges require æfront endÆ investigation and analysis, robust engineering design and disciplined implementation and operation. Newcrest Mining Limited has focused its efforts on the development of gold/copper projects of substantial scale and margin. To help achieve this, the company is applying and further developing mass mining methods. These include large-scale open pits (OP) and underground mining methods such as sublevel (SLC), block (BC) and panel caving (PC). Block and panel caving now offer economies of scale opportunities for Newcrest to achieve high production rates at lower production costs; thus enabling the exploitation of mineral endowments at higher margins. This paper discusses the practical aspects of caving technologies that Newcrest continues to develop through its expertise at Telfer and Ridgeway SLC operations, Ridgeway Deeps BC and Cadia East PC projects.

Jan 1, 2008

The collapse of the I.T.C., the subsequent fall in the price of Tin, and the lifting of quotas saw the Renison concentrator resuming full seven- day operations at maximum capacity in 1985/86. Performance was sus- tained in terms of grade and recovery, and in some areas improved, over this period. A further challenge was declining head grades, and the need to treat higher proportions of less amenable ore types. The complexity of the flowsheet and the method of mining and ore handling predisposes the process to unstable operation, and solving this problem comprises a major component of the current development effort. The concentrator has an imbalance of capacity between processes, and excess in some areas is being adapted to enhance the capacity of others. Magnetic susceptibility of various minerals is being exploited to greater effect. Significant performance gains are achievable by improving exist- ing unit process efficiency, particularly in grinding, gravity processes and Cassiterite Flotation. This paper reviews the metallurgical developments, both recently implemented and planned for this year, which have contributed to main- taining Renison Limited in a competitive position in the post I.T.C. Tin industry.

Jan 1, 1988

By Valenti M

A by-product of the lead smelting operations at BHAS is a copper-lead matte typically containing 35% copper, 38% lead and 12% sulphur. A hydrometallurgical treatment process has been developed for the treatment of this matte to recover copper as cathode and results in a lead-sulphur residue which is recycled to the lead smelter. A commercial plant with a nominal capacity of 4000 tpa utilising this process was commissioned during 1984. This plant has been shown to be capable of producing copper cathode at rates approaching 4000 tpa over short periods of time.

Jan 1, 1989

By P Mason, J F. Huntington, K M. Scott

Short-wave infrared (SWIR) spectral reflectance of the hydrothermally altered volcanic rocks in the footwall of the Hellyer Zn-Pb massive sulfide deposit was measured with a portable PIMATM infrared spectrometer. The Al-OH absorption band was used to derive information on the cation composition of white mica. The wavelength range of the Al-OH band from 2194 nm to 2222 nm reflects variation in the number of octahedral Al (Alvi) in white mica from 3.9 to 3.2 (based on four octahedral cations per formula). This Alvi range indicates a substantial compositional variation, covering most of the compositional region between muscovite (Alvi = 4.0) and phengite (Alvi = 3.0). Moreover, the spectral reflectance data show that the compositional variations of white mica are spatially related to the hydrothermal alteration zoning, such that the white mica of more phengitic composition tends to form in the main upflow fluid channels in the centre of the footwall alteration system. The results suggest that the octahedral Al content of white mica, which is spectrally definable by the wavelength of the Al-OH band using a field instrument such as the PIMATM, can be used to map fossil hydrothermal systems and potentially as vectors to mineralisation.

Jan 1, 2004

The behavior of a curved wall under earth pressures for a horseshoe shaped tunnel lining is considered to be closely related to the beha vior of a vertical beam with variable flexural sti-"ness on an elastic foundation. In stress analysis an approximate method which divides the axis of the tunnel lining into small finite lengths and replaces the integrals by summation is usually adopted. this method is extremely complicated and tedious. However the variations of the moment of inertia from point to point along the wall axis can be expressed by a power function inversely .eith the distance from the ll )ottom and the analytical method can still used. The equations for the calculation of deflection, rotation, bending moment, shearing urce, and soil reaction of the curved wall are derived in nondimensional forms in this paper.

Jan 1, 1987

By Yuanping H

There is a practical method of handling methane in a fully mechanized high output coal face when the methane outflow rate from the face is too high to be handled by ventilation alone, a combined method would be adopted. Before adopting this method, above all, the sources of methane outflow, which can be divided into methane in the intake airflow and methane emitted from the working seam and from the worked-out area, are determined by air-methane measure- ments in the tail gate and intake conveyor gate or by air-methane measurements in the working space of the coal face. Then, in

Jan 1, 1988

A brief review of currently available "commercial" information on methods of treating ilmenite s to produce high titanium content "upgrades" is made. In this back- ground the CSIRO/Murphyores Process is described and its relationship to other methods Discussed.

Jan 1, 1972

In recent years there have been a number of excellent towns built for mining communities in remote parts of Australia. Planning has been thorough, and very large capital expenditures have been made by companies to provide high standards of accommodation, services and amenities. But so often the phrase 'company town' comes to be applied, expressing the frustrations of the residents, working for a single employer who dominates their lives, and of the company, which would prefer not to have to build and operate a town. The much-vaunted early success of some iron ore, bauxite and coal projects has led to a belief that the success of all mining projects is assured. Those holding this belief ignore the vagaries of mineral deposits and of markets, and the need to amortise large high-risk capital expenditures, much of which is spent on social and industrial infrastruc- ture. This expenditure on infrastructure does not have to be

Jan 1, 1975

By Pollard D. M

The BHAS copper-lead matte leach process, developed in Port Pirie, South Australia, has been in operation on a commercial scale since 1984. This process is one of many developed in the past decade to recover copper via the hydrometallurgical route. In essence, the process involves a single stage agitative leach of 100% -75um matte in an acid chloride-sulphate lixiviant with gaseous oxygen as oxidant. The leach temperature is controlled at 85¦C to assist with reaction kinetics. After leaching, divalent copper is recovered from solution via a conventional solvent extraction/electrowinning circuit to yield cathode copper for sale The BHAS matte leach process has several unique characteristics cf. other commercial oxidative acid leach processes. These include i) the use of gaseous 02 as oxidant ii) H2SO4 addition as make up acid iii) Relatively low chloride ion addition (30 g/1) For this reason, extensive work was carried out into the optimization of leaching by Meadows (1985). Variables investigated included ò Oxygen flow-rate ò Agitation intensity ò Leach temperature ò Free acidity ò Chloride ion concentration ò Matte particle size The current work was conducted to determine the effect of cooling rate, and hence mineralogy, on the leaching characteristics.

Jan 1, 1989

By S P. Suthers, J M. F Clout, J J. Campbe

An advanced technique for modelling hydrocyclone separation performance has been developed. This technique is based on the combined modelling of hydrocycloning parameters and ævirtualÆ iron ore feed. The virtual feed modelling was performed using a novel (in-house) software package called æRecognitionÆ, which uses data from optical image analysis to classify the particles in certain size fractions according to total iron content and calculates data for every grade class. These data include the average mineral composition and density of every liberation class in every size fraction. This information about every size fraction, representing the ævirtual feedÆ, was input to the mineral processing modelling package USIM PAC. The hydrocycloning process was then modelled for this virtual feed using the Plitt hydrocyclone model. Empirical calibration coefficients for the hydrocyclone model were calculated using an optimisation procedure in Excel. Pilot-scale hydrocyclone beneficiation experiments were performed on an iron ore blend, using different hydrocyclone pressures and per cent solids in the feed pulp. These experiments were modelled and the modelling results were compared with the experimental results. The new modelling approach enables prediction of the recovery of each mineral in the products, calculation of the total iron grade and recovery, and optimisation of iron ore beneficiation using hydrocyclones.

Jan 1, 2005

During the last 20 years, manufacturers of Australian iron have given increasing attention to development of external markets for processed blast furnace slag. Slag has been in widespread use overseas and data on the performance of Australian slag in concrete lave shown it is suitable for that use. Chemical and physical properties of typical Australian slag products including air cooled, granulated and pelletised slag are discussed and compared with local natural aggregates. Special attention is given to pumping achieve- ments with slag concretes and the observed durability of concrete after many years service. More'recent applications for granulated slag as a sand replacement are discussed. It is concluded that'whilst more wide- spread use of slag is possible, the cost of marketing and transporting slag are likely to restrict opportunities unless for local usage.

Jan 1, 1979

By Davey KJ

Complex sulphide ores are characterised by complex texture of the valuable minerals. Any assessment of the performance of differential flotation circuits treating such ore should include analysis of the effects of poor liberation of the valuable minerals. Selected samples were taken from balanced size by size surveys of the flotation section of a concentrator treating an ore body containing fine grained galena and sphalerite in a matrix of iron sulphides which is mostly pyrite. liberation measurements were made using the QEM*SEM system on four or seven size fractions. The measurements indicated that less than 40 per cent of the galena and less than 60 per cent of the sphalerite in the flotation feed was liberated. The final concentrates were largely composed of composites of valuable minerals and iron sulphide however there was a small but significant fraction of liberated iron sulphide. Using the sized mineral flows obtained from the original balances and the liberation measurements, a satisfactory liberation balance was obtained. This enabled the effect of liberation on the flotation performance to be examined; not only for the entire circuit but also in the rougher, scavenger and cleaning sections. In the zinc circuit the effect of a regrind mill could be assessed. Recovery of galena in the lead circuit was limited by the recovery of composite lead particles. Recovery of liberated galena exceeded 95 per cent in all size fractions while the recovery of composite galena exceeded 85 per cent below 38 ¦m but fell sharply above 38 ¦m. Examination of the behaviour of the liberated and composite galena in the various sections of the lead flotation circuit revealed high recoveries of both liberated and composite galena particles in the roughing and scavenging sections but very low recoveries in the final two cleaning stages. Similar trends to those observed in the lead circuit applied in the zinc circuit although the performance of the liberated sphalerite also fell off at sizes greater than 38 pm in this case. Thus the zinc recovery was limited by the flotation of both the liberated and the composite sphalerite. The effect of regrinding was to increase the recovery of sphalerite mainly by reducing the amounts of sphalerite in less liberated sizes rather than by increasing the liberation of the sphalerite within a given size Fraction.

Jan 1, 1993

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

New and more cost-effective methods of haulage and hoisting will be needed to develop the underground mines of the future. A review of the development of technology since the 1950s shows that once mechanised equipment became available it took 25 years for appropriate mining methods to be developed and the equipment made reliable, then a further 25 years to reach todayÆs level of automation and reliability. Suggestions are made about possible areas for ongoing research with the observation that there is little research worldwide into disruptive technologies. A call is made for better organisation and presentation of the opportunities and potential benefits of new underground mining technologies.

Jan 1, 2005

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

Exploration by Cyprus Minerals Australia Company (formerly Amoco Minerals) has successfully outlined significant Au-(Cu) mineralisation at Starra, 150 kilometres south-east of Mt. Isa. Mineralisation is stratabound and localized in deformed and metamorphosed ironstones (B.I.F?) and iron-oxide bearing schists of the mid-Proterozoic Staveley Formation. Over 90% of the presently outlined potential ore occurs in 4 discrete zones within a strike length of 3.5 kilometres. The inferred geological resource in these zones is approximately 6 million tonnes grading 5 grams per tonne gold and 2% copper. Roughly half of this is open-pittable, but more rigidly applied mining criteria will probably reduce the exploitable tonnage. Detailed infill drilling is in progress and a pre-feasibility study has commenced. The joint venture partners, Cyprus Minerals (75%) and Elders Resources (25%) expect to make a development decision by the end of this year.

Jan 1, 1986