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By Sofoulis I

Recent studies in the Archaean of the Kalgoorlie-Norseman area show that the layered rocks can be subdivided into two main units, both containing basic igneous rocks and sediments. The lower unit is distinguished by the presence of acid volcanic flows and sills. In some areas, clastic sediments become coarser and,pas-s into conglomerates. This passage is accompanied by thinning of the beds. These features and their distribution suggest a basin of subsidence flanked-by areas of shallow-water deposition. -.

Jan 1, 1964

The general theme of the paper is a resume of factors which induce management to explore for oil, gas, coal and uranium in Australia. It is non-technical in the sense that apart from brief references exploration techniques are not covered. The central theme is the interplay of such diverse factors as taxation, mining 'regu- lations, exploration costs, availability of competent personnel, potential markets within and outside Australia, projected prices of sources of energy and their distortion by governmental action including restrictions on international trade for economic or political reasons, the role of the so-called multi- national companies, extreme views by pressure groups on the preservation of the environment, the availability of funds for exploration and the possible returns to the providers of exploration monies.

Jan 1, 1974

Increases in mechanisation and mining at greater depths are leading to additional problems of heat and humidity in many mines. As a result there is now an escalating demand for temperature prediction simulations appli- cable to underground environments. After a brief review of the present situation with regard to world mining and the use of environmental programs, the paper goes on to discuss in moderate detail the mathe- matical modelling of the many parameters that govern the condition of the ventilating air in a mine. The development of a program that gives the temperature distribution for a mine ventilation system is then outlined. The practicality of the program is discussed and the presentation format for users is explained. Simplification of input data requirements and the acquisition of data from other planning programs are an integral part of the commercial application of this program.

Jan 1, 1977

By R F. Weinberg, R A. Armstrong, A G. Tomkins

We investigated the duration of formation of the giant Ok Tedi porphyry copper-gold deposit in Papua New Guinea using zircon SHRIMP U-Pb dating. The intrusions that host the Cu-Au mineralisation have a maximum age of 1.43 ¦ 0.22 Ma. Since previously published K-Ar dates on the same intrusion constrain the last thermal event at 1.11 ¦ 0.05 Ma, we conclude that the magmatic-hydrothermal event that produced the deposit lasted ~0.45 million years (Myr). A comparison of Ok TediÆs calculated volatile fluxes with those from arc volcanoes and active mineralising hydrothermal systems suggests that the efficiency of metal deposition is a key factor in determining the duration of deposit formation. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

In his letter of resignation as General Superintendent of the Broken Hill Associated Smelters (BHAS) prior to taking up aconsulting position at imperial Smelting, G.K. Williams wrote that he considered his major contributions at BHAS were:the development of large scale sintering machines;the double tuyere-row blast furnace; continuous lead refining.Despite his well deserved reputation as a scientist, based on his advancement of the metallurgical chemistry underlying lead refining processes, Williams reveals that he considered commercial implementation as the ultimate measure of technological success. Furthermore, he clearly did not differentiate between the scientific and the empirical as a means of achieving that end.

Jan 1, 1985

Australia had been enjoying a market boom led by the mining sector and West Australian mines were leading the way to satisfy the massive demand for our natural resources, especially from China. However, the Apache gas explosion on Varanus Island, 97 km off the west coast, has clearly demonstrated how the unexpected can suddenly impact on profitability and investor confidence for the mining industry. Risk management with contingency planning can provide the most cost-effective solution to help ensure mining projects are successful. For this discussion we will focus primarily on contingency planning, CP for mining projects à and how to plan for the unexpected. The Apache gas explosion will be our example æUnexpected EventÆ. Insurance may provide financial compensation but it will not protect your reputation as a reliable supplier or prevent damage to investor confidence and future mine projects. However, contingency planning can provide real protection for mining projects à to survive the unexpected.

Jan 1, 2009

Milling Practices Ore is direct tipped into a gyratory crusher and crushed to minus 209mm and fed to stockpiles for the blending of grade into the mills. Secondary and tertiary crushing reduces the mill feed to minus 12mm. Mill feed is a blend of breccia and porphyry ore into two primary mills with the overflow to a regrind mill and then into the leach tanks, followed by a conventional counter current carbon in leach circuit. Underflow from the cyclones feeds back into the primary mills for additional grind. An unusual feature of the Mt Leyshon milling circuit is a desire to produce scatts. The scatt by product is the polished base rock of the Mt Leyshon Breccia clast and contains little grade. These scatts are produced because of the additional time and energy required to produce a proportionally small quantity of gold. The residence of these scatts in the mills decreases the mill feed rate. Scatts account for twenty percent of the mill feed and are screened from the discharge of the primary mills.

Jan 1, 1990

The primary objective of designing, constructing, commissioning and operating a technically and economically viable processing plant cannot be achieved without a rigorous scientific understanding of the chemical principles underlying every facet of the total flowsheet, from feed preparation through to a final product. Having developed a thorough understanding of the chemistry involved, the next challenge is to match the innovative advances with the necessary engineering skills. In simple terms, there is little point in proposing a new processing route if it is not possible or practical to design, construct, commission and operate it. Thus to achieve our objective, it is necessary that processing facilities that are both smarter and cheaper be developed. This presentation highlights a number of the more significant research and development activities that are designed to facilitate the conversion of a smart idea into a real process. Following a brief discussion of several examples, the presentation concludes with the observation that a pro-active team approach is almost mandatory in order to achieve an acceptable outcome.

Jan 1, 2000

By J L. Bos, D J. Readett

As mining progressed through the Girilambone oxide orebodies, down to the primary sulphide zones, each successive stratiform layer yielded copper bearing ores of changing mineralogy and grade. Constant changes, innovations and optimisation were required to be applied to the heap leach, solvent extraction and electrowinning operations, to efficiently produce LME Grade A quality copper cathodes from this ore. The changing ore types required various crushing, stacking and heap leach irrigation methods to ensure that optimum recovery from the predominantly low-grade copper ores was efficiently achieved. Subsequently, innovations such as heap aeration and heap rejuvenation techniques were implemented. The constant selective removal of copper from the maturing heap leach liquors, coupled with an increase in iron(III) concentration, required solvent extraction optimisation. Changes to the original solvent extraction circuit configuration, combined with changes in operating parameters and procedures, allowed effective processing with changing heap liquor compositions. The electrowinning tankhouse was also upgraded and optimised through continued testwork and monitoring, to maximise cathode production and quality

Jan 1, 2000

The rights of nations to explore and exploit minerals in the continental shelf were recognized by the 1958 Convention on the Continental Shelf. The Commonwealth Government has expressed the view that, as a party to the Convention, it has, by virtue of its foreign affairs power, full rights to legislate with respect to offshore minerals. States have taken the view that the rights recognized as extending into the continental shelf are land mineral rights, which belong to the States, and the Commonwealth legislative power in this field is strictly limited. Without prejudice to each other's rights, Commonwealth and States agreed to "mirror" legislation in relation to offshore petroleum. Commonwealth and State legislation, of which the operative parts are in identical terms, are both administered, in relation to areas adjacent to each State, by State Ministers of Mines. The legislation has functioned well in practice, though difficulties are encountered by the Commonwealth Government due to lack of direct accountability to Commonwealth Parliament. An alternative scheme designed to overcome this problem is outlined.

Jan 1, 1974

By M M. Tarshan

Separator performance is evaluated by the so-called separation efficiency. The concept of efficiency in mineral dressing operations must be interpreted with considerable care. Although qualitative use of term efficiency is valid and useful, difficulties arise in expressing it quantitatively because two conflicting criteria, grade and recovery are normally involved in its evaluation. It is undesirable to express efficiency as a single value, even though this is frequently done in practice, since there are strictly speaking an infinite number of combinations of grade and recovery that can give that one value. Inefficiencies in processes can be attributed to three broad sources: mineral limitations as represented by the separability curves, equipment limitations (which prevent the maximum separation indicated by the separability curves), and human failure to minimise these inefficiencies. In the present paper, the efficiency of a two-constituent separation process has been examined. The separation process has been evaluated by comparing the sharpness factor of the actual, the absolutely efficient and the absolutely inefficient operations.

Jan 1, 2000

By McGregor GW

The Utah International group of companies has a wide geographic spread of operations, including a significant interest inAustralia's largest coking coal operation in Queensland, steaming and coking coal mines in USA, a copper mine in Canada, a half interest in an iron ore operation in Brazil, a number of smaller operations, and a significant portfolio of undeveloped properties in South America, South Africa and South East Asia.The opportunity to acquire this group of companies presented an immediate problem to BHP in that it was regarded as too large for BHP to absorb by itself. In addition, there was a concern that such an acquisition would increase BHP's coking coal exposures to unacceptable levels. Despite these dilemmas, BHP was keen to acquire Utah.A plan was therefore developed and agreed to by General Electric (GE) (the then owner of Utah) which would give BHP nine months in which to put together a consortium to share in the ownership of the Queensland coal assets (plus coal assets owned by BHP), and to arrange a project financing for use by BHP and the consortium. BHP would own 100% of the rest of the assets.

Jan 1, 1985

By Wall L, Dobos S. K, Berry-Lyons W

The air we breathe and both plant and animal matter consist largely of nitrogen, oxygen carbon and hydrogen; each of these elements has two or more isotopes, The rocks, soils and waters on which we live and from which we extract minerals and other resources are comprised of elements such as oxygen, silicon, hydrogen, sulphur, iron and magnesium; each of which has two or more isotopes. Since isotopes of an element behave identically in chemical reactions, they cannot be separated or analysed by chemical means. The different isotopes of a particular element, however, vary in mass, reflecting the variation in the number of neutrons in their nuclei, so that physical processes based on the relative atomic masses of the isotopes are used to separate and analyse them (eg, mass spectrometry). Many biologic, atmospheric and geologic processes alter the ratios of the different isotop1ees of many elements. The isotope ratios D/H and O/ O, for example, exhibit significant variations in natural waters because of isotope fractionation during evaporation and condensation. Isotope analyses of both naturally-occurring and synthetic isotopes in the near-surface and biospheric environments can be used to understand natural processes and predict the results of man's interaction with his environment.

Jan 1, 1991

There is a link between the requirements of society and the determination of curricula in tertiary educational institutions. Mineral resources exploration provides a strong example of this link. The resources exploration business engages in scientific, engineering, commercial and management activities in an endeavour to discover economically extractable commodities. Most geoscience and geotechnical graduates are employed by the mineral industry for resource exploration and development. This industry comprises a wide range of employer groups which include the Bureau of Mineral Resources, CSIRO, energy authorities, State geological surveys, State water commissions and private companies. Such employers are variously charged with the task of understanding and utilising earth resources to the benefit of society. It follows therefore, that undergraduate education and post-graduate specialization should be directed towards meeting the needs of employer groups in the geoscientific and geotechnical fields. In the past the training of most Australian geologists has emphasised classical science. This type of training remains of primary importance in the early undergraduate years but there is a need for modern educators to recognise the increased desirability for the inclusion of geotechnical subjects in the curriculum. Modern geo-education should address four main sectors when deciding curricula:

Jan 1, 1986

By Salehi M. R

Although inherent mineral matter appears to have no effect of the reflectivity of inertinite in the reflecting light microscope, it has a marked effect on the grey levels resulting from the backscattered electron response in the scanning electron microscope. Inertinite with a high inherent mineral matter content has a high grey level response but not as high as that of mineral matter. The highest grey level response is with inertodetrinite which at times could be mistaken for mineral matter. Fusinite has a higher grey level response than semi-fusinite. The backscattered electron grey level response corresponds to average atomic number and hence approximately to density. If a porous structure develops and becomes filled with mineral matter such as S, Cl, Ca, Si, and Al the grey level will be higher. Micrinite has an unusual response in that it behaves like an exinite maceral in the SEM rather than an inertinite maceral. It either has a low grey level when relatively free of inherent mineral matter, or a low grey level background with high level granules corresponding to Si and Al dominantly. Similar structures have been found in exsudatinite and resinite. It is thought that micrinite results from the migration of hydrocarbons out of exinite giving a porous structure which usually accommodates inorganic matter.

Jan 1, 1991

By J-M Rendu

Substantial progress has been made over the last ten years in the development of uniform national and international standards covering the definition, estimation and public reporting of mineral resources and mineral reserves. Agreement between the major participating countries has been reached, which includes the requirement that a Competent Person prepare and approve publication of mineral resources and reserves. Most national regulatory organisations have accepted the new standards and have included them in the rules that must be followed by mining companies operating under their jurisdiction. These developments are the result of a concerted effort on the part of professional societies, national regulatory agencies, international organisations, and many dedicated individuals. The historical development of these standards is summarised in this paper. Accepted definitions of mineral resources and mineral reserves are discussed, as well as the definition and role of the Competent Person. Additional effort is needed before the international standards are fully understood, accepted and followed by mining companies, regulatory agencies, the investment community and the general public. Steps being taken toward development of an International Code are outlined.

Jan 1, 2002

By P J. Harper

Maximising shareholder value is a widely stated strategic goal of many mining companies. Mining projects can be capital intensive and achieving good returns is essential to encourage future investment in the industry. Despite the widely accepted importance of shareholder value, the minerals industry is often accused of providing relatively poor returns when compared to other industries. There are many recent and well publicised examples of minerals companies that have failed to deliver value to their shareholders. There are numerous business improvement initiatives employed within the mining industry to assist mine operators improve performance. Some are more effective at creating value than others. Benchmarking is one technique that is commonly used to identify performance gaps and target and prioritise opportunities for improvement. However to be effective, Benchmarking must be used appropriately and result in actions that lead to measurable operational improvement. When conducting a Benchmarking project it is important to remember that the aim should be to improve value. For this to be achieved, the strategic goals must be incorporated into the process. This paper details a structured and comprehensive approach to conducting a successful Benchmarking project. Focusing on Benchmarking as a technique for measuring and improving operational performance in underground mines, the underlying drivers of best practice in underground mining are identified.

Jan 1, 2005

By A I. M Ritchie, G P. Timms

Monitoring of water infiltration into WhiteÆs waste rock dump at the Rum Jungle mine site in the Northern Territory, Australia, started in 1983, and has since produced a unique and long-running data set. Following closure of the uranium mining operations at the site, a soil cover was constructed on the dump in 1984 primarily to reduce water infiltration into, and the quantity of low quality effluent out of, the waste material. The performance of the cover in reducing water infiltration has been monitored using ten lysimeters installed across the dump prior to construction of the cover. Over the past eight years or so, the average infiltration rate as measured by the ten lysimeters appears to have risen compared to the early years of monitoring. The significance of this apparent increase is discussed given the variability observed in the data from individual lysimeters, and the variability in the rainfall. Estimates of the infiltration rate as measured by each of the lysimeters are examined using statistical tools. It is concluded that the infiltration rate has increased with time and with increasing rainfall. The increase with time is a stronger factor than the increase with rainfall. It is further surmised that the cover system at the locations of the lysimeters is less effective now at reducing infiltration into the dump than it was when newly installed.

Jan 1, 2003

Present value maximisation studies are a useful aid in enhancing the economic performance of open pit mining operations. Maximising present value helps to reduce the risk of financial failure. Maximisation of present value also means that the capital invested is being used most efficiently. A characteristic step in determining the present value of an open pit mining operation is to set out the sequence in which increments of material (ore of various grades and waste rock) are mined. Traditionally, present value maximisation has been performed by selecting a cut-off grade for each increment so as to maximise the present value of the total operation, by an iterative process using computers. Kenneth F Lane has developed a method and applied it to many mining operations. An alternative method for determining the maximum present value of an open pit mining operation is given. In this method the maximum present value is determined by working backwards from the end of the operation life, progressively asking the question of each increment `what cut-off grade maximises the the present value at the start of mining of that increment?' The method allows calculations to be performed by a `spreadsheet' package. Present value determinations are characteristically performed under constant conditions (eg prices, costs) throughout the operation life. Unfortunately real life circumstances are rarely constant, with the costs of mining inputs rising at variable rates. The prices received for mineral products have been shown to broadly trend downwards with time in real terms. Treatment of such changes in the determination of the maximum present value of an operation is discussed.

Jan 1, 1994

By S La Brooy, C Fountain

Throughout its history the mining industry has focused on the highest-grade deposits sited in the most convenient locations. The burgeoning global population and higher standards of living not only increase the demand for mineral products but also make it harder to mine and process them. The future will include the development of lower-grade, more complex orebodies, and orebodies in difficult locations. The industry will be expected to provide for humanityÆs needs while reducing its environmental footprint and maintaining profitability. This paper reviews some of the likely adaptations in mineral processing that will occur over the next 20 years. The challenges inherent in adapting to lower grade and more complex materials might be exacerbated by such factors as the availability of water and low-cost energy. In underground mining, higher energy costs are likely to foster further developments in underground preconcentration, especially for ores that can be upgraded at relatively coarse sizes. The adoption of underground crushing could also render material amenable to semi-dry preconcentration options such as might be achieved by the rotary classifier developed by CSIRO and being commercialised by RCR Tomlinson, or more modern versions of the hand-sorting of ore that use sensors based on colour or other suitable rock properties. The cement industry and some gold roasters have used the alternative of dry grinding and classification, which might also have a part to play in dry processing. There is also likely to be increased interest in options such as in situ leaching that further minimise the surface disturbance. Underground operations will have to balance the energy savings from reducing the amount of material brought to the surface and reduced surface disturbance against the practical limitations of installing and maintaining processing equipment underground. On the other hand, surface disturbance and energy issues in open cut operations will be balanced by potentially lower mining costs and higher overall recovery from the deposit.

Jan 1, 2008