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By Ralph B. S

Bacterial leaching of low grade quartz felspar porphyry copper ore was studied in large-scale laboratory percolation leaching columns.Limitations in the release of soluble copper showed up before fifty per cent recovery, due to occluding precipitates of iron oxides and hydroxides. Precipitates were removed by increasing the acidity of irrigation feed four-fold with respect to sulphuric acid. However, irrigation at low pH (pH 1.5) inhibited copper leaching. Resumption of bacterial leaching at pH2 was achieved by introducing a period of non-irrigation. The results suggest a 'direct' attack by bacteria on the chalcopyrite substrate rather than an 'indirect' ferric-leach mechanism.

Jan 1, 1981

By Ramsden AR, French DH

The limited contrast range of conventional black and white imaging does not enable full use to be made of the dynamic range of the video signal obtained from a scanning electron microscope or microprobe. The use of false colour substantially increases the information that can be derived from such images enabling relationships to be displayed that cannot be observed in black and white. This capability is now used extensively in combination with quantitative electron microprobe analysis as a research tool for ore characterization and host rocks studies related to minerals exploration in the CSIRO Division of Exploration Geoscience.

Jan 1, 1989

By Madsen I. C, Langberg D. E

Recent advances in X-ray diffraction (XRD) technology have made it possible to conduct powder XRD measurements on samples at high temperatures during reaction. State-of-the-art detectors are now capable of rapidly acquiring diffraction patterns across a wide angular range (typically 120"20) enabling phase transformation rates to be measured directly during sample reaction. In this study, the phase transformations during the reduction of hematite to metallic iron by five per cent hydro ºen in nitrogen gas mixtures, were measured in situ between 500 - 700 C. Complete X-ray diffraction patterns were acquired within 15 seconds every one minute, enabling direct measurement of the transient phase abundances during the reaction. The data were quantitatively analysed by the Rietveld method to yield the abundances of hematite, magnetite, wustite and metallic iron, as functions of time during the reduction process. A first-order reactions-in-series model was proposed, and the reaction rate constants and activation energy were determined from the time-dependent phase abundance data.

Jan 1, 1999

By J Addai-Mensah, M Adam, W Skinner, J Begelhole, K Quast

Granulation of iron ore fines into robust granules is critical to successful sintering and blast furnace operations in iron and steelmaking. Iron and steelmakers desire iron ore granules with high strength, uniform size distribution and low fuel consumption to enhance efficient sintering operation. Unlike hematite ore, magnetite concentrates do not granulate easily at low binder dosage to yield coarser granules due to the absence of nucleus particles. This motivates the present study to harness the complementary properties of hematite ore to enhance granulation of magnetite concentrates via blending. The current state-of-the-art in hematite and magnetite blend granulation is reviewed, along with granule property limitations. Preliminary experimental work on granulation of hematite and magnetite blends as a precursor to sintering is reported.CITATION:Adam, M, Addai-Mensah, J, Begelhole, J, Quast, K and Skinner, W, 2017. Enhancing magnetite concentrate granulation by blending with hematite ore, in Proceedings Iron Ore 2017, pp 17–24 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

In Broken Hill, Northern Rhodesia, two water jacket lead furnaces have been in operation for the past three years. The furnaces were erected in war time, and only absolute essentials were procurable. The water for the jackets was obtained from wells adjacent to the works, in a dolomite formation. There being no water-softening plant, except a small one capable of treating water for the power plant only, this water was found to make a heavy scale in the jacket. During 1917 several jackets were burnt through, resulting in serious trouble and loss of output. In order to avoid this, furnaces were stopped twice a month for 8 hours and scale was removed as far as possible. In addition to the scale trouble during the summer months, a green slime grew in the supply tanks and occasionally became detached from the tank and collected in the cocks near the jackets. This caused risk to the jackets and was difficult to remove without a stoppage of the furnace. In 1918, bundles of wattle bark were placed in the hot well at the rate of one ton per month. These extracted the tannin and added from 0.5 to one part of tannin per 100,000 to the circulating water. The hot water was cooled over a brushwood cooling tower and returned to the supply tanks. The well water required to, make up the wastage was estimated at 40,000 gal per day.

Jan 1, 1920

Neutralization with lime is a simple, cheap, and effective means of treating acid raffinates from uranium processing to' raise the pH, reduce the concentrations of dissolved salts (including heavy metal impurities), and remove amine by adsorption. Two-stage neutralization, using limestone in the first stage at approximately pH 4 and lime in the second, lIlay be advantageous.Lime neutralization of mffinates in the pH range 7 to 8· 5 generally reduced the radium ·concentration to 10 to 200 pCi 1-1, but ·there was considerable scatter in the experimental data. The radium concentration was further reduced to less than 3 pCi 1-1 by co-precipitation of barium (radium) sulphate with 10 mg Ba (as barium chloride) per litre of raffinate. Adsorption of radium on barytes was -also effective in reducing the radium concentration in neutralized raffinate to less than 3 pCi 1-1.The radium concentration of pit water was readily reduced to less than 3 pCi 1-1 when pit water containing 0·01 M sulphate as ammonium, calcium, or sodium sulphate was treated with 20 mg Ba per litre of pit water.Adsorption on barytes was also effective in removing radium from pit water containing 0·03 M sulphate.

Jan 1, 1975

By M D. Taylor, G Duclaux, K Atkinson, L A. Fisher, A R. Latham, M F. Gazley, S J. de Beer, C M. Tutt

Geological logging by mine and exploration geologists involves the application of a logging code that requires a geologist to make a subjective decision to classify a particular rock unit. This will most likely result in inconsistencies in logging that will be difficult to monitor or assess over time. A potential solution to this problem is to have an objective method to determine the true nature of a given rock unit. This can be achieved using portable X-ray fluorescence technology (pXRF), as large geochemical data sets can be collected rapidly and at low cost. Plutonic Gold Mine (Plutonic), Western Australia, has a growing data set of more than 150 000 pXRF multi-element analyses from core and underground face samples, reconciled to Au fire-assay concentration, and logging codes. This study investigates and statistically validates the consistency with which the logging codes have been applied at Plutonic for the last four years, with respect to both Au distribution and other elements. In doing so, we have developed a schema that allows objective logging to occur once core has been sent for assay and analysed by pXRF. While far from replacing the geologist in the field, this is a complementary method that adds significant value to a data set.CITATION:Gazley, M F, Tutt, C M, Latham, A R, Duclaux, G, Fisher, L A, Taylor, M D, de Beer, S J and Atkinson, K, 2013. Objective geological logging using geochemical multi-element data - Plutonic Gold Mine, Western Australia, in Proceedings World Gold 2013 , pp 455-462 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The pyrite-sphalerite-galena and barite orebodies at the Rosebery mine are concordant with the shale host rock and have been deformed into one system of folds with an associated axial plane cleavage. The folds are tight and overturned with east-dipping axial planes. Folds in the sulphide ore are commonly disharmonic, particularly between adjacent bands of different composition.Concentric style folds occur in the competent bands, e.g. pyrite-rich bands. Similar style folds are predominant in the less competent sphalerite-galena-rich bands and also in the shale of the host rock. The trends and plunges of the fold hinge-lines are variable but axial planes are of reasonably constant orientation throughout the mine area. The folds in the orebodies are of limited axial extent, approximating to conical folds, and are arranged in en echelon patterns. The fold system was possibly formed in one period of folding by heterogeneous strain that may have been caused by the presence of a mass of tectonically mobile sulphide ore. Lineations parallel to the ore/host rock contacts appear to reflect movement between the ore and the host rock during folding.

Jan 1, 1972

By K Ehrig

You are a geologist, geometallurgist, or metallurgist/process engineer and are fortunate enough to work for an organisation who asks you to design/execute a geometallurgy program. What seems like a simple request is actually not a trivial exercise. æRecipeÆ style manuals are not readily available. However, many æexpertsÆ are lurking around willing to deliver solutions which will solve all of your problems. Even though similar ore deposit styles (e.g. porphyry Cu, IOCG, Ni-laterites, calcrete hosted U, etc.) have many similar characteristics, each ore deposit is unique. Hence your geometallurgy program needs to be æfit-for-purposeÆ. This paper offers some insights gained via designing and executing geometallurgy programs from exploration through to production, and working at a mine where you are held accountable for your metallurgical performance predictors.CITATION:Ehrig, K, 2013. Geometallurgy - What do you really need to know from exploration through to production?, in Proceedings MetPlant 2013 , pp 28-33 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By J Temos

This paper outlines a number of immediate practical approaches to continuous improvement in environmental management in the minerals industry. It puts these into context with longer time-frame step-change approaches whose gestation may take a decade. Examples of improvements and approaches are drawn from WMC operations.

Jan 1, 2002

The kinetic and practical aspects of the extraction of copper from copper-rich solutions by cementation on iron was investigated. Tests were made on the effect of stirring speed, cupric sulphate concentration, acid concentration, temperature, and ferric sulphate concentration on the reaction rate and excess iron consumption.Most kinetic investigations were conducted under a nitrogen atmosphere to prevent any oxidation of the iron or copper metals. The stirring mechanism for all tests incorporated the use of a rotating impeller above a static disc in the solution. The activation energy for cementation on the steel disc at high stirring speed was 8·6 kcal/mole, indicating a predominant chemical control.Increasing the pH first decreased, then above pH 3, increased the reaction rate. Additions of sodium sulphate also significantly increased the reaction rate.The use of high temperature and high pH under an inert atmosphere has been suggested for increasing the reaction rate and producing a high purity sponge copper product.

Jan 1, 1972

By Baker G

The exposures resulting from development work, following on the discovery of a new shoot of hIgh grade ore at the north end of the Sardine tin mine, during 1952, have provided an unusual opportunity to study the oxidation of a stannite-rich ore. Through the kindness of C. C. Morton, Chief Government Geologist of Queensland, an exactly located suite of specimens representative of the exposures was supplied by J. and W. Reddie. This was later supplemented by a number of specimens culled from a parcel ofrepresentative ore submitted to the Melbourne Ore Dressing Laboratory for testing.The Sardine tin mine, near Ewan, Queensland, has been the outstanding producer of the Kangaroo Hills Mineral Field. Since its discovery in 1918, up to 1952 it has yielded about 1,500 tons of cassiterite concentrates, and about 85 tons of stannite concentrates. The outcrop ore averaged 35% tin oxide, but the grade declined with increasing depth, and by 1930 had fallen to 7% tin oxide. In the northern section of the mine the ore shoots show a downward passage to complex primary s.ulphide ore, containing cassiterite and abundant stannite.The orebodies occur in a series of fissures in a crushed zone about 50 ft. wide in slates and quartzites that have been intruded by granite (Connah, 1952). A quartz porphyry dyke forms the footwall of the original main lode in its southern part, being traced' from the surface to' the No. 4 level (173 ft. vertical depth), and two narrow dolerite dykes were encountered in the workings north of the main...

Jan 1, 1954

An important consideration in any mining operation is waste disposal management. Tailings management at Macraes gold mine allows for the disposal of tailings into fully engineered embankment dams and overburden material to be incorporated as construction material into those embankment dams. This paper outlines the current tailings management practices.

Jan 1, 1992

THE nature of the ore deposit of the Broken Hill line of lode is such that it can be broadly divided into two the calcitic and siliceous ore bodies. The principal minerals occurring in these ores are: Galena, sphalerite, pyrite, arsenopyrite, chalcopyrite, pyrrhotite, calcite, rhodonite, garnets, feldspar, fluospar, quartz.Whilst these minerals persist in both classes of ore, the following typical analyses of Broken Hill South Limited ore bodies will give some indication of the disposition with regard to each:

Jan 1, 1928

By D Craw, C Smith, C Rufaut

Oceana Gold (NZ) LtdÆs, Macraes Gold Operation currently has two tailings impoundments, the larger of which covers approximately 75 ha. When an impoundment is temporarily out of use, the surface dries and dust can be blown from the surface to the surrounding area. At present water spraying is used to stabilise the surface, but this is not ideal as Macraes mine can experience water shortages during the summer. This paper examines an alternative method of surface stabilisation using vegetation as a ground cover. The tailings have a low natural fertility, so it is important to determine what will actually grow in the tailings, and whether amendments are necessary. Also important is the effect of the amendments on arsenic mobility in the tailings as the schist rock at Macraes has naturally elevated levels of arsenic. Three plants species, rye corn, barley, and lupin, were grown in metre-deep lysimeters at Macraes mine site. The plants were grown in unaltered tailings, and tailings with one of two amendments added: Bioboost (an organic fertiliser containing biosolids), and superphosphate fertiliser. The leachate from each lysimeter was collected and analysed monthly to determine the extent of arsenic mobility. In addition, laboratory experiments were set up to determine arsenic mobility in tailings with amendments at the centimetre scale.   All plants grew best with the fertiliser amendment, with rye corn growing the best overall. Plants growing in unaltered tailings either barely survived (rye corn, barley) or died (lupin). Plants in the Bioboost amended tailings grew only slightly better than in the unamended tailings. Laboratory experiments indicate that the addition of phosphate fertiliser greatly increases arsenic leaching at the centimetre scale when compared to unamended tailings. The addition of Bioboost only marginally increases arsenic leaching, compared to unamended tailings. This trend has not been repeated in the lysimeter trials on the metre scale over four months. Current results suggest that of the plant types trialed and amendments used, rye corn with superphosphate is the most practical short-term tailings stabilisation method at Macraes.

Jan 1, 2004

By Lavers G

Factors governing the dissolution of nickel and iron in pentlandite and pyrrhotite concentrates from Mt. Windarra were studied for aqueous solutions at normal temperatures and pressures. The effects of dissolved dioxygen, carbon dioxide, hydrogen ions, and chloride ions are described. The direct reaction of aerated water wiili pyrrhotite is much faster than with pentlandite, and reaction rates are proportional to the dissolved dioxygen concentration. In both cases divalent metal sulphates are produced initially. The subsequent oxidation of iron(II) to iron(III) and its oxolation produces acid solutions which rapidly attack both minerals. The presence of carbon dioxide or chloride ion has little effect on these rates.

Jan 1, 1976

BATMINÖ, BATMINEÖ, BATMINDÖ are an abbreviation for Business Analysis Tools for Mining, Mine Evaluation and Mine Design respectively. BATMINP are proprietary tools customised to suit individual client requirements. The first suite of tools provides for analysis and evaluation of open pit mining equipment alternatives and includes fleet selection, fleet sizing and production, productivity and economic outcomes. The models address all mine process activities including drilling, blasting, loading, hauling and auxiliary services. All models are built to provide for simultaneous evaluation of multiple alternatives that are time and condition related. Provision is made for modelling from first principles and/or default or shortcut inputs. Sensitivities to key input parameters are easily performed and consistent logic is applied throughout the process. The models are built to provide key outputs in a format suitable for presentation and documentation. Provision is also made in the models for validation of both inputs and outputs through benchmarking, back analysis and budget comparison. The same models can be used for short interval (12 month) planning and control, medium-term (three to five years) and long-term life-of-mine (LOM) planning. Millions of dollars are spent each year on mining plant and equipment. Decisions that impact on the medium and long-term are made. BATMINP tools have been used to perform studies with good results and in most cases the studies have been validated through back analysis and comparing model outcomes to real data.

Dec 6, 2010

One common public perception of mining is that financially it is an extraordinarily risky business. Another and contrary view, in certain circles, is that price risk and other financial risks can be relatively easily removed or shifted by a number of schemes or devices. In reality, beyond the orebody discovery stage, mining need not be any more risky than most heavy industrial businesses. Nevertheless, as stated by Rappaport, (1986): Risk is a parameter of central importance in establishing the economic value of any asset. The level of risk is determined both by the nature of the firm's operations and by the relative proportions of debt and equity used to finance its investments. These two types of risk are commonly referred to as 'business risk' and 'financial risk' respectively. The term financial risk is used somewhat more loosely herein to recognise the reality that any risk inadequately addressed in the design, construction and operation of a mining project can have significant financial consequences; usually negative. For instance, a specific area of business risk in mining is often called technical risk which definitely has severe financial consequences if not managed correctly. The various risk shifting, hedging and risk management tools available all have their place and range from merely useful to almost indispensable. However, in the long-term, financial risks are maintained at acceptable levels by the application of sound, more fundamental business management principles. There are many with a vested interest in perpetuating a perception that the conceptual foundations of sound management practice are extremely complex. In reality, most management concepts are prosaic, but their application requires incredible discipline and hard work. There is no magic formula or 'silver bullet'. It appears that a company whose activities are restricted to mining can analyse the range of risks specific to mine development and operations more clearly than companies in which mining is just one of many businesses. The almost universal failure of large oil companies in the mining business is probably the best example of lack of any clear comprehension of fundamental business characteristics and risks. Conversely, in regard to risk management, choosing to be in other business as well as mining does nothing to reduce the risks of the mining business. The individual shareholder can probably make such 'diversification of portfolio' decisions better than most management teams. It could be argued that diversification across a number of disparate businesses may actually increase overall corporate risk due to lack of management concentration and focus. These differences between the perceptions of financial risks and the realities in mining need to be further elaborated in relation to some uncompromising business concepts.

Jan 1, 1994

Owing to the increased consumption of sulphuric acid; Australian manufacturers have, from time to time, been seeking for a satisfactory source of sulphur that would make them independent of foreign supplies.Some years ago a considerable amount of acid was obtained from the roasting of Spanish pyrites. This ore, in 1913 or thereabouts, cost 16s. per ton f.o.b. Huelva, and freight to the eastern seaboard of Australia was about 20s. per ton. As the ore contained 48% to 50% of available sulphur, it was costing roughly 9d. or 10d. per unit, and, in addition, the cinder, after roasting, was a product of considerable value to smelters, containing as it did a high percentage of iron suitable for fluxing, and appreciable values in silver and gold.

Jan 1, 1925

By Carter D

The Chairman of this afternoon's session is Dick Carter. This afternoon is the culmination of this conference. We've looked in the first session at regulation; in the second session at valuation techniques and this session we look at valuation in practice. Dick's involvement in the mineral industry has been wide ranging and distinguished. Dick has worked with BHP since 1960, when he joined BHP Steel as a commercial trainee. Dick holds a B.Comm. from the Newcastle University College of the University of New South Wales and was educated at the Australian Administrative Staff College and Harvard Business School Advanced Management Programme. During the past decade, he has headed the minerals group's Aluminium Divison, Resource Planning and Development, Non-Ferrous Metals and Business Development Organisations. Dick currently serves as Executive Director of BHP Gold Mines Limited and Managing Director of Ok Tedi Mining Limited. His experience covers Australian Manganese Company, Mineral Deposits Limited, Northern Rivers Rutile, Tasmanian Electrometallurgical Company Limited, Mount Newman Joint Venture, Worsley Aluminium and Carnilya Hill Joint Venture Operating Committee. His industry associations include the Executive Board of the Gold Producers Association, the Federal Executive of the Australian Goldmining Industry Council as well as the World Gold Council. Ladies and gentlemen, Dick Carter.

Jan 1, 1989