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By Morland R, Peck R

The Joint Committee of The Australasian Institute of Mining and Metallurgy (AusIMM) and the Australian Mining Industry Council (AMIC) have published a Code for the Reporting of Identified Mineral Resources and Ore Reserves. The Code is the result of an initiative begun in 1971 to achieve industry self regulation of Resources and Ore Reserves reporting which resulted first in guidelines for reporting standards but which have now been incorporated in ASX Listing Rules as a Code with significant sanctions ensuring compliance. This paper describes the background to the Code, its key provisions, and comments on practical aspects of working with the Code and compliance issues.

Jan 1, 1990

Future metal prices play a direct role in both the economic evaluation and short to medium planning of a mine scheduling sequence. It is difficult to predict with accuracy the future price of volatile metal commodities, however, it is possible to fix some future metal price, outside of long term contracts by the selling of futures contracts through a commodities exchange. The futures contract represents a fixed amount of a speci- fied quality of a commodity for future delivery at a predetermined price. Several different types of hedginc are possible, one in particular which is best suited for mining companies. There are relative advantages and disadvantages when trading in futures contracts and particular reference is made to gold contracts on the Sydney Futures Exchange.

Jan 1, 1980

Mining and metals projects have tended to increase in both scope and cost to a point where many projects are Droperly designated as superprojects. Specialist engineer- constructors have developed organisations and systems to provide project management services during the design and construct phase of large projects. However, the engineer-constructor is also required to provide a wide spectrum of services during the evolution of large projects prior to the construction phase. Some common phases of pre-construction evolution are identified together with the associated types of specialised services which may be required. A project management team approach is described which has been developed for the design and construct phase. It is suggested that a modified matrix organisation could be adapted to the provision of special- ised services as well as to project management for ore-construction phases of the project.

Jan 1, 1980

Due to geographical location, AustraliaÆs economy and trading are closely related to Asia. With ChinaÆs increasing demand on resources and energy and Japan and KoreaÆs steady imports in these fields, AustraliaÆs mining industry is experiencing a so called æboomÆ period. Traditionally, engineers or skilled workers from South Africa, Britian or other parts of Europe moved to Australia for its mining industry. Now, more students from Asia are starting to choose mining engineering (similar choices include mining geology, metallurgy, geotechnical engineering and mining surveying) and expect to work in these fields. How does AustraliaÆs mining industry face such a situation? What kinds of challenges and opportunities do the mining industry and universities face? How do mining companies utilise these human resources? This paper concludes with an analysis of all these questions at an industrial level and some personal deduction as to the preferred course for international students.

Jan 1, 2005

In presenting the paper, Mr. Davey quoted subsequent work which yielded k, at miscibility gap composition, of about 50.We can confirm the authors' findings for k j 300 for nearly pure tin to k 2 about 50 (average 47) from our own experience and from repeat experiments on materials described by the authors, at 1150°C.During laboratory-scale trials we also found confirmation of the authors' view that it is more difficult to reach equilibrium from the high-iron (in slag) side than from the low-iron (high-tin) side. Working from the high-iron side tends to yield results that point to a high k, leading to optimistic values of iron/tin ratio in final slags. In practice the smelting of a tin concentrate, unless it is exceptionally low in tin and high in iron, must yield initially a tin-rich slag and therefore equilibrium can only be reached from the "tinny" side.

Jan 1, 1967

This brief overview of the history of Brown Coal mining in Victoria is a luncheon presentation -I do not intend to make it indigestible with extensive listings of resources or production. There is a vast pantry of collated historical records and of vari- ous predictive studies available for the enquired with a hearty digestion. A gourmet collation is provided in The Aus IMM Monograph No 11 published in 1984 entitled "Victoria's Brown Coal-A HUGE FORTUNE IN CHANCERY", currently still on offer by the Institute and available at a bargain price in the foyer at this conference. Monograph No 11 also provides a feast of excellent references on the theme of Victorian Brown Coal assembled by the several contributors. In contrast, my presentation paper is a fast-food service, extracts from the printed paper only-you have no choice-you "get what you get" and in small quantity. I hope it will tantalise your appetite -like Oliver Twist you will ask for more. -Buy the Monograph!

Jan 1, 1989

By Lawson F

Pyrite concentrate and calcine from the Nanjing Lead-Zinc-Silver Mines, China, were leached with aqueous cyanide and thiourea solutions. More than half of the contained gold and silver was able to be extracted from the roaster calcines. The very fine dissemination of precious metal grains, high roasting temperature (850 - 900°C) and residual sulphur are believed responsible for the Iow extractions.A recovery of about 70 per cent for both silver and gold was able to be obtained with cyanide and with thiourea leachants when the pyrite was roasted in the laboratory at temperatures between 600 and 650°C.Thiourea, as an alternative leachant, has received much attention recently and a series of constant potential leaching tests was conducted.When the thiourea to formamidine disulphide mole ratio was about two, the precious metal extraction was greatest. In the Nanjing calcined material, this occurred at a potential of about 210 mV relative to a standard calomel electrode.

Jan 1, 1987

The Bowen Basin of Central Queensland covers a total area of 3 200 000 ha. The Basin has proven reserves of about 24 000 000 tonnes of coking coal and steaming coal which constitutes about 70 percent of the known coal reserves in Queensland. Large scale open cut coal mining in the Bowen Basin commenced at Moura in 1959. There are now 16 open cut mines operating in the Basin and they collectively mine through about 3000 ha of land each year. Most of the land which has been mined has previously been used for extensive grazing. No mining has yet taken place on cropping land although coal reserves underlie land which has been cropped or has potential for cropping. The primary objectives of almost all of the mining companies operating in the Bowen Basin are to rehabilitate mined land to a stable and productive form which is compatible with surrounding land use which is dominantly grazing. The acceptability of these objectives is considered against the prospect of mining of cropping land and the qualified success of the return of rehabilitated land to grazing uses.

Jan 1, 1987

By Y A. Stepanyants, J Crawford

A practical field method for determining the maximum value of the intrinsic oxidation rate, Smax , of sulfidic materials in waste rock dumps is proposed. Knowledge of the intrinsic oxidation rate of sulfidic materials distributed in a dump is necessary for predictive modelling of oxidation and pollutant generation over time. The suggested method uses the fact that drilling waste rock dumps to install probes for monitoring temperature and oxygen concentration causes large volumes of air to be injected into a dump by the drill rig. By measuring the rate of decrease of oxygen concentration along the length of a borehole immediately after installation, it is proposed that Smax can be calculated at different depths. The aims of this work were: to derive a simple, practical formula for the estimation of Smax from the oxygen concentrations measured over time, based on some simplifying assumptions; to use a two-dimensional numerical model that incorporates all the necessary physical processes to model the behaviour of an aerated dump over time for a reasonable range of dump and material parameters; and to compare the results of the two approaches to assess the validity of the simple formula as a method for estimating Smax. It has been found that the technique can provide reliable estimates of Smax when the value is of the order of 10-7 kg(O2) m-3 s-1 or greater. At the lower end of the range however the radius of the zone aerated during drilling becomes an important parameter and further work has been recommended to investigate this aspect of the method.

Jan 1, 2003

By O Ostrovski

Direct iron smelting reduction has been examined using a modified 50 kg induction furnace. The furnace was equipped with continuous raw material feeding, a top oxygen lance, argon bottom bubbling, and sensors for measurement of gas and bath temperatures, gas composition and other parameters. In the base case, iron ore was charged at the rate of 1.5 kg/h, coke flowrate was adjusted to maintain a char fraction in the slag at 30 wt per cent, the oxygen flowrate was 100 Nl/min and the post-combustion ratio (PCR) was 60 per cent. The PCR was varied from 45 to 75 per cent by changing the lance height relative to the bath surface. Smelting reduction of Whaleback iron ore was investigated at different post-combustion ratios and iron ore feedrates using coke and coals with different volatile matter. The rate of iron oxide reduction increased with increasing iron oxide concentration in the slag, with a slight deviation from a linear function. The post-combustion ratio affected iron ore reduction and partitioning of elements between phases in the smelting reduction furnace. The high volatile coal investigated was found to be unsuitable for iron smelting reduction in the laboratory furnace.

Jan 1, 2000

By P Louden, C Rothnie, G Showers

Tiwest employs several methods to assess the quality of heavy mineral concentrates in ore and process samples. Mineralogy is determined using a method called MA98, developed in conjunction with JKMRC over the last three years (Zhang and Whiten, 2001). A range of other techniques are also used to characterise ore, heavy mineral concentrates and mineral products. MA98 is the culmination of efforts since 1989 to determine mineralogy from chemical analysis without recourse to heavy liquid fractionation, which has traditionally been used to discriminate between light-heavy , zircon, rutile and leucoxene. The major advance with MA98 is the use of statistical mass balancing for all chemical species, as opposed to reliance on key chemical species for each mineral. Three magnetic fractions are analysed by X-ray fluorescence spectrometry, with a minerals balance performed for each. Heavy mineral concentrates processed by this method include drill samples, process samples from the wet concentrators and Dry Mill, and mineral products. TBE can be avoided for higher heavy mineral grade samples since quartz is determined from SiO2 balance. In this sense the method is sufficiently universal and robust to cope with a wide range of sample types and compositions. The MA98 algorithm provides abundant information in addition to mineralogy, including TiO2 and Fe2O3 grades of ilmenite and leucoxene, and concentrations of weakly magnetic zircon and kyanite. Information such as this is invaluable in tracking different minerals through the processing plants. Other ore assessment procedures used by Tiwest provide for modelling of orebodies by mineral sizings, Fe in zircon, and FeO and U+Th in ilmenite. Microscopy is used to provide important qualitative information such as grain shape, surface staining and degree of cementing. These quality measurements are included with mineralogy in geological ore models and are available for mine scheduling. In using the above methods to characterise heavy mineral concentrates, Tiwest is better placed to predict and monitor plant performance and product quality from any ore zone.

Jan 1, 2001

THE following description of the surface plant of the Great Fitzroy Mines is to be understood as having been compiled by a mechanical engineer, who concerns himself more with the various appliances used, their correct construction to enable them to accomplish their prescribed work, and the production and transmission of the power required to operate them, than with the reasons for the physical and chemical processes which those appliances are called upon to assist in carrying out. Hence the metallurgist will not find herein more than the skeleton of the organism, which perhaps he would wish to be clothed with the detailed description of the substances undergoing treatment, in their various combinations, at all stages, and the results attained in separating the valuable constituents from the worthless. So, also, no details will be found of the methods employed by the management for. the purpose of determining by sampling and assaying the nature of the various products obtained.GENERALThe ore being worked at the Great Fitzroy Mine is divided into two classes :-1. Ore that requires concentration before smelting.2. Ore that can be smelted direct.Flow-sheet (Fig. 1) shows in outline the process of treatment to which ore of the first class is subjected, and the writer will endeavour to fill in that outline with some details of the appliances used.

Jan 1, 1911

IN any assay office it is of paramount importance to keep the men interested in their work; and in order to do this, men on routine work, such as lead, zinc, and sulphur deterrrrinations, slag analysis, etc, should be changed around monthly. This gives some variety and helps to keep a man's interest on his work, so that better work results. It may be maintained that to keep a man on the same class of work indefinitely makes him more expert at his work. This is certainly true; but in assaying, where accuracy is so essential, it is absolutely necessary for a man to keep his mind on the work, and not 'get' into a mechanical method of working. He is also on the alert to discover means for shortening his analytical methods, and his capacity forwork is increased. Another advantage is that the men get a good all-round training, and one is never at a loss to replace a man on any class of work when he is absent from any cause. This tends to smoother and more efficient running of the assay department. In industrial assaying it is often advantageous to have a result quickly, so that it will be of maximum benefit in the running of some part of the plant, In such a case it pays to sacrifice a little accuracy to speed up a method. The shortest method is less costly, and a quick approximate method is all that is required to give the superintendent the requisite information. Time is thereby saved, and the cost is less. In carrying out assaying for any large industrial plant, such as a smelting works, there is always a tendency for superintendents running the different departments to send in more samples for assay than are absolutely necessary when no system of costing is in operation. Some of these samples may involve a lot of work and heavy expenditure, as, for example, the estimation of only one impurity in a sample of refined lead. If the superintendent knows that the cost of assaying all samples sent in by,him is charged up directly against...

Jan 1, 1922

By O Ostrovski

Iron ore reduction and iron cementation by CH4-H2-Ar gas was investigated in a laboratory isothermal fixed bed reactor. Iron ore was first reduced to metallic iron by hydrogen, then carburised to cementite by methane. Increasing temperature and hydrogen content accelerated the reduction process. Methane had almost no effect on the reduction process. Meanwhile, higher temperatures increased the rate of cementation and also the rate of free carbon deposition. The optimal temperature for cementite formation was found to be 750¦C. At this temperature, reduction of iron ore to cementite by gas containing 55 vol per cent hydrogen, 35 vol per cent methane and 10 vol per cent argon was completed in about 15 minutes. Addition of sulphur into the reducing/carburising gas strongly retarded the process of cementite formation and free carbon deposition. Cementite is an unstable phase which decomposes to iron and carbon. The rate of cementite decomposition increased with temperature up to 600¦C and above 750¦C . In the temperature range from 600¦C to 750¦C the rate of cementite decomposition decreased with temperature. Cementite was the most stable at 750¦C and least stable at 600¦C. The two-interface grain model was used to describe the process of iron ore reduction and the volume reaction model was employed to model the iron cementation process. The simulated results for both reduction and cementation are consistent with the experimental data.

Jan 1, 2000

Prospecting in arid terrain can produce substantial environmental impacts, comparable to or greater in magnitude than the impacts associated with actual mining or petroleum production. Impacts are likely to be particularly severe where prospecting involves intensive geophysical exploration, especially in areas which have escaped degradation by other land uses such as pastoralism. With appropriate environmental planning and management, however, the environmental impacts of prospecting in arid terrain can be greatly reduced and mitigated, at low cost. In many countries, prospecting licences, exploration leases and associated tenements now carry a range of conditions relating to environmental protection. The assessment, avoidance and mitigation of environmental impacts is therefore an important component of and-zone exploration. My aim here is to give an overview of some of the main aspects of an environmental planning and management (EPM) programme for prospecting in arid terrain (PAT). Detailed operational prescriptions for environmental protection procedures are necessarily specific to particular areas and types of prospecting: see. e.g., Buckley (1982a, 1984, 1985a, 1986a), Klepacki et al. (1985) and Stone (1986). The intention here is to provide a checklist rather than a recipe book: as an aid in incorporating environmental aspects into the overall planning and management of an exploration programme, and in liaison with company environmental staff, consultants and regulatory bodies. I also hope to show that whilst some of the techniques used in particular environmental disciplines certainly require specialist expertise, the overall design of an EPM programme is not in the least esoteric, but simply an exercise in straightforward common sense. Perhaps this paper could be subtitled: "Demystifying environmental Planning".

Jan 1, 1988

A number of mines in Australia have experienced premature detonations caused by bulk explosives reacting with the rock type being blasted. Premature detonations are extremely high risk events as they are unplanned, occurring at any place, at any time, potentially resulting in high loss (personnel and equipment). Many Australian mines have also experienced spontaneous combustion where spilt explosive reacts vigorously with the rock type. Premature detonation in these cases does not occur due to the lack of confinement and the volume of explosive present, but these reactions could impinge on the surface initiation system and provide an early warning of future premature detonations. The explosive ground reactivity phenomena is not restricted to Australia with similar incidents being reported in North and South America, South Africa, China and South East Asia. All reported incidents have two common denominators, being the presence of sulphide rock types and nitrate based explosives. Both premature detonation and spontaneous combustion result from the same series of reactions of partially weathered sulphides that ultimately result in the violent decomposition of the ammonium nitrate based explosive. A number of relatively easily observable indicators can be used to assess a particular minesiteÆs potential for explosive ground reactivity. The presence of two or more of these indicators means that minesite personnel should contact their explosives manufacturer for assistance in determining if a problem exists and if so then developing strategies to overcome the situation. The paper describes the indicators as well as discussing, via a case study, the holistic approach required to efficiently develop a relevant æSafe and Efficient Blasting ProcedureÆ to deal with explosive ground reactivity problems.

Jan 1, 1999

By J P. Wyethe, D P. Padayache, B R. Green

The development of an ion exchange process for the recovery of vanadium from solutions containing low concentrations of vanadium and/or slurries is discussed. The process can be used to improve overall vanadium recovery throughout the plant, and/or to reduce the vanadium concentration of waste materials prior to their disposal. The development of the process on a laboratory and miniplant scale is discussed, and includes:selection of a suitable resin with the desired loading and elution characteristics; laboratory-scale testwork to evaluate the use of the resin in both resin-in-pulp and fixed bed configurations; recovery of a high-value vanadium product from the resin eluate; and a preliminary techno-economic assessment of the financial viability of the process.

Jan 1, 2000

By E Drueppel, M Mistry, J Pateiro

As mining undoubtedly influences the natural environment future challenges of copper ore mining are minimisation of land use in area and duration, proper land rehabilitation as well as tailings management. One possible solution to avoid these negative impacts could be the application of underground mining with backfilling tailings compounds. This approach would definitely increase the production cost. Against this background the project analyses the influence of an æecologically satisfyingÆ copper ore mining on world market prize and demand as well as on the environment. In the project 261 copper ore mines accounting for 98 per cent of world copper production have been examined. After modelling a backfill plant, analyses of applied backfill techniques were conducted. Afterwards a method of cost estimation was developed and then the backfill plant model was applied in three case studies. The results were transferred into scenarios. The work closes with a short discussion and gives an outlook to forthcoming research. The results presented in this work have been generated within the Collaborative Research Center (CRC) 525 entitled æResource-orientated view of metallic raw material flowsÆ. This interdisciplinary project was established at Aachen University of Technology (Germany) in 1997 and is funded by the Deutsche Forschungsgemeinschaft (DFG). The long-term goal of this research program is the identification of options for the resource-sensitive supply and processing of metallic raw materials. In order to address the sustainable development challenges facing the metals and minerals industry an integrated resource management system is to be developed and tested for important metallic raw materials. Case studies for aluminium and copper are being conducted by the CRC 525 in order to provide useful and efficient tools for decision makers over the entire life cycle of these materials.

Jan 1, 2003

The mining industry has had lengthy experience with risk management involving technological situations imposing risks to people and property. In such situations the relevant parameters can be fairly well defined, the outcomes can be broadly predicted and probabilities of these can be estimated. Accordingly quantitative risk assessment can be applied. In recent years there has been increased emphasis in risk management on a broader set of potential consequences. These include potential impacts on the flora and fauna of ecosystems. These are typically poorly understood and this is especially true in Australia where the vast size of the continent and sparse population make gathering a comprehensive data base on biological resources a difficult task. The resulting scientific uncertainty and ignorance regarding the potential for serious or irreversible harm to the environment mean not only that quantitative risk analysis techniques are not appropriate, but also that the precautionary principle (PP) needs to be applied as a complement to qualitative ecological risk analysis. The potential for significant impacts is particularly high in Australian ecosystems. These comprise one of the 12 æmegadiverseÆ regions of the world in terms of biodiversity and, hence, have global significance. Moving from risk management to application of the PP by the mining industry provides a significant challenge. Application of the PP has no clear guidelines to follow and, to-date, has been highly unpredictable. However, there is much to be gained for industry in embracing this challenge and taking a pro-active approach in exploring methods that will provide for clearer guidelines and hence more certainty in outcomes of environmental management decisions involving precaution. As well, there could be considerable other advantages for the mining industry in terms of reputation assurance, community acceptance and greater certainty in terms of access to resources.

Jan 1, 2000

By J D. van Wees

Preliminary project evaluation is relevant to the evaluation process of the decision makers (or executives) prior to making the critical business choices. Important to the assessment is an integrated sensitivity, scenario and risk analysis at every stage of a mining project. This should include the evaluation of different options taking into account uncertainties. Construction of interactive financial computer models where each element is functionally integrated into a fully integrated life-cycle allows rapid and automatic study of the sensitivity of each element through changes in the value of an input. The scenario analysis is the effect of changing more than one input at a time, organised through scenarios in a decision tree. Risk analysis is an integrated analysis of the effect of all uncertainties of the parameters, using Monte Carlo simulation. Key to the asset decisions process is that the decision maker is provided with the essential integrated decision information. We have clustered this information into several scenario groups. Within each group, two levels of uncertain information are distinguished: discrete scenarios critical for the decisions; and remaining uncertainty within the scenario (risk analysis) which can be modelled by continuous probability density functions (pdfÆs). For an asset, the relevant scenarios in each group and the associated continuous pdfÆs need to be defined. When the scenario groups and associated pdfÆs have been defined for the asset, the decision process can be started by structuring the different scenario groups in a Scenario Tree. A Scenario Tree contains decision and end nodes. Each end node corresponds to a completely defined mine project or asset model. The calculations for each end node result in a set of stochastic realisations for the reserves, production forecast, cash flow, and profitability indicators (NPV, IRR, DPR). Thus, a deterministic and fully probabilistic multi-commodity analysis tool is provided to investigate the sensitivity and robustness of decisions.

Jan 1, 2003