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The economic valuation of mineral prospects usually involves DCF analysis of expected revenues and costs. Traditional approaches deal with price uncertainty by considering different price scenarios and may even consider cases where prices drop sufficiently for production to be suspended temporarily. This paper outlines recent extensions to the methodology derived from finance theory. We present a simple analytical model that focuses on the value of operational flexibility where future prices are uncertain.

Jan 1, 1988

By Schulz R. S, Staunton W. P, McGuire J

The increased activity in the Australian gold industry over the last decade has resulted in a concomitant increase in the use of sodium cyanide, with a projected consumption of 80,000 tonnes per annum by 1991. Growing environmental awareness by government, industry and the public has generated increased interest in the fate of cyanide near gold mine tailings dams and has highlighted the lack of basic knowledge in this area, particularly for Australian conditions.

Jan 1, 1991

By Middlebrook PD

The problems of education and research in the extractive metallurgy area are being tackled by the University of Melbourne through activities centring on the Department of Chemical Engineering. The establishment of the G.K. Williams Laboratory and the enhance- ment of the teaching of material relevant to extractive metallurgy in the Chemical Engineering course aim-at providing graduates and experienced researchers for the industry and at providing a strong research group carrying out industrially significant research in the area of pyrometallurgy.

Jan 1, 1986

Mine planning for ore recovery by open stoping and pillar recovery is becoming more sophisticated, but there are basic operating constraints which must be imposed if this planning is to realise the production results on which the mine is dependant. The production reliability of an open stope is usually a high priority and common design problems can be identified. A range of practical considerations which should be considered at the mine planning stage are reviewed including equipment performance, blasting technology, ventilation requirements, development layouts, lead time, ground conditions, support, backfilling and ore recovery.

Jan 1, 1982

By Xin J

In China, the State-run mines are currently practising an information card management system, to collect data about mine production and safety condition. Since large volumes of data will be obtained every day, efficiently and effectively processing data and sorting out valuable information will take enormous resources of manpower, if by hand. Therefore, an intelligent database system with easy data inputting was developed to assist information processors in data classifying, filing and retrieving. For analyzing and improving production performances, reliability models and production functions were embodied. The system was implemented on AST-286 in DBASE M. Preliminary applications have proved effective and successful.

Jan 1, 1991

The design of drawpoints in caving and stoping mines has a significant impact on the productivity of the operation. Drawpoints must be designed to provide uniform drawdown and maximum recovery of the broken ore within the limits imposed by the dimensions of the stope, the stability of the pillars, the method of draw, material flow characteristics, etc. The design of drawpoints historically relied on the mining engineerÆs experience and intuition. However, in many operations, empirical analyses have also produced important information regarding design geometry. Factors that affect the sizing and spacing of drawpoints are discussed and guidelines are provided for their design in order to obtain maximum recovery of broken ore and reduce hang-ups.

Jan 1, 2000

Economic evaluations of mineral projects are based on discounted cash flow analyses, followed by sensitivity and risk analyses. However, the global macroeconomic and political environment in which the mineral industries operate have a profound effect on the viability of individual projects. Since the oil crises of 1974 and 1980, demand patterns for minerals have become much more variable and prices more volatile. Significant changes in the geographical distribution of world mineral supply and demand are underway, and the mix of minerals used is also changing. Social and political factors are as important as economic and technical factors in determining the viability of mineral ventures. Economic evaluation of mineral projects have to be undertaken in a more uncertain and risky environment. They can no longer be reduced to a number crunching exercise.

Jan 1, 1987

By Warren R. P

When the original Mount Gunson joint venture, between CSR and United Uranium ceased operations in December 1971, an intensive ex- ploration campaign was launched to prospect for more ore in the Mount Gunson region. This campaign resulted in the discovery of the Cattle Grid deposit. A comprehensive sampling programme proved the existence of 4.6 million tonnes of ore, at a mean grade of 2.4% Cu, calculated at a 1.0% Cu cut-off. The planning and development programme that followed this discovery included not only the mining and metallurgical aspects of the exploration of the deposit, but also the en- vironmental aspects. Preliminary work included data collection with respect to meteorology, soil types, and existing flora and fauna.

Jan 1, 1976

The word `environment' may have many different meanings but, for the purposes of this paper, I have assumed the definition included in the Environmental Protection Act 1986 (Western Australia). This Act defines `environment' as `... living things, their physical, biological and social surroundings, and interactions between all of these'. The Act further defines the `social surroundings of man' as `... his aesthetic, cultural, economic and social surroundings to the extent that those surroundings directly affect or are affected by his physical or biological surroundings'. This gives a very broad meaning to the idea of environment and environmental issues, and it is therefore understandable that the influence that environmental issues have on mining activity can vary so much from state to state, and even within states, and why the degree of influence can change so much with time.

Jan 1, 1990

Metal smelting is seeing a continual increase in intensity and throughput in recent years. This is done with increasing demand for cost/capital efficiency, higher recovery, and managed environmental impact, among other things. With the development of more intense smelting processes, the issues of refractory wear, mixing and separation of reacting phases and the nature of the reactions between them become more prominent. Understanding of interfacial phenomena is in growing need, in addition to knowledge of the bulk properties of equilibrium and transportation. The GKW CRC has a suite of projects aimed at developing various techniques and expertise to provide information of interfaces in metallurgical systems. This article illustrates some recent development in this area, particularly in studies of melt/refractory contacts, the determination of surface and interfacial tension of metal/slag/matte melts, modelling slag-metal mixing and studies of kinetics of the smelting reactions.

Jan 1, 2000

The metallurgical works of the Electrolytic Zinc Company is situated on the Derwent Estuary, approximately five miles north of the city of Hobart and near a relatively dense housing area. Zinc concentrates, consisting chiefly of zinc and sulphur, have been roasted at Risdon for 53 years;- recently at rates of 1, 100 tons per day. The zinc content of the ores is converted to zinc calcine (ZnO), which is a dusty material. The calcine is leached with acid to form zinc sulphate, which is then electrolysed to make zinc. The sulphur is oxidised during roasting to sulphur dioxide, part of which is converted to sulphuric acid and part is dissolved in estuarine water which is then discharged to the Derwent Estuary. Photographic slides were exhibited showing the unaffected green flora of the nearby hills, of clear exit stacks, of green lawns, and of a w ll lrcnt nines hnlP anlf nniir.qa within the Wnrka hnnnrla_rv_

Jan 1, 1971

By Richards AG

The stimulus of major capital expenditure in establishing open cut coal mining operations in the Hunter Valley led Coal & Allied Industries to look to a computer based information system as a tool to assist mine management in day to day operating decisions, as well as to provide a base of comparative data to help in long term equipment procurement decisions. The mine information system was conceived as an integrated set of three subsystems; costing, production recording, and maintenance. The maintenance management features of the system are closely keyed to a policy of preventive maintenance and maintenance costing based on user specified parameters. Central to this policy is the maintenance work order, which may be created and updated directly via interactive procedures at visual display terminals. The, system was designed for on-line processing in a multi-mine shared operating environment. Each mine controls its own data capture, and most other processing functions directly from terminals. The system is currently operational on the Combined Group Services Pty Ltd FACOM M150 computer, located in Newcastle, NSW.

Jan 1, 1983

The current boom in the mining sector has required mining operations to ramp up production to meet the international demand for minerals. This increase in production is putting enormous pressure on on-site professionals, and in particular the role of the on-site geotechnical engineer is ballooning. Mining engineers are focused on machinery and schedules; geologists concentrate on grade control and resources; everything else becomes the responsibility of the geotechnical engineer. Day to day geotechnical engineering is very different from geotechnical design work, and a practical understanding of both is required to successfully carry out either role. In addition, a successful geotechnical engineer has to have a good understanding of almost all technical aspects of mining. Even more important are good communications skills and the ability to problem solve on the fly. None of these skills are taught at tertiary institutions and therefore need to be learnt in the workplace. However, the shortage of geotechnical professionals means that young engineers do not always receive the mentorship and training they need to develop confidence and technical effectiveness. This paper outlines the changing role of on-site geotechnical engineers and presents some thoughts on how industry and young engineers can adjust to the changes.

Jan 1, 2006

Australia today is one of the leading countries in the fields associated with the mineral industry, an industry which accounts for over 50% of overseas income and revenue to government. This is no accident. In order to be competitive in what was recog- nised very early in the country's history as a highly profitable busi- ness, the Australian mineral industry (mining, extractive and refining metallurgy) has traditionally been very innovation con- scious, a characteristic which has been evident from the begin- ning of the industry or very nearly so: Australia's geographic isolation and the dispersion of the mineral industry over wide distances made an exchange of ideas difficult and often impossible. One needs only to look at the inaugural address given by Sir Henry Ayers, the first president of the then Australasian Insti- tute of Mining Engineers, in Adelaide on 4th April, 1892 (1) "There is probably no other pursuit which depends more on its productive development and profitable results than in the extent and application of the scientific and mechanical knowledge possessed and exercised by its manager." and "Having in view the value of the mining industry of Austral- asians, they should be urged to apply their best skill with all the scientific and mechanical knowledge obtainable to its future development."

Jan 1, 1988

A feasibility study will fail its objective if it does not identify and then correctly assess, all the risks which could have a substantial impact on the financial viability of a project. Before this assessment can be undertaken, one needs to understand the risk profile of the entity which is making the decision about the project. Some of the commonly encountered issues when assessing project risk are related to the problem of not being able to see the wood for the trees. In any risk analysis it is important that conservatism does not strangle a viable project; that the variables are internally consistent with each other, that reality checks are carried out and that appropriate expertise is used. Sensitivity analysis forms a part of the overall project risk assessment; however, it can only test those variables which have already been identified in the financial model. The most useful tool in performing a sensitivity analysis is Monte Carlo simulation. When properly used, it provides a more real world scenario than the simple adjustment of key variables by ¦ 10 per cent one at a time. Monte Carlo can provide valuable information about the robustness of a project. Project risk and sensitivity assessment is prone to the analysis paralysis syndrome. The focus should be on quality rather than quantity.

Jan 1, 1997

By Arbuthnot IM

It is the commonly held belief that, because the separation of liquids from solids takes place considerably faster in high rate thickeners than in conventional thickeners, high rate thickeners (HRT's) must use more flocculant than conventional thickeners. Data collected from a wide range of thickener users in Australasia and data presented in the literature is analysed. In addition, pilot plant data, with direct comparisons between HRT's and conventional thickeners, is presented. It is concluded that the flocculant consumption for both thickener types is in the same range.

Jan 1, 1991

By S Miller, R Smart, J Thomas

Single-addition and sequential net acid generation (NAG) experiments were carried out on natural and prepared samples with varying contents of organic matter and pyritic S. Results show that carbonaceous matter can produce significant quantities of organic acids during peroxide oxidation in the NAG test, which leads to overestimation of acid-forming capacity and misclassification of benign samples as potentially acid forming (PAF). Organic matter effects were most pronounced in samples with low S (less than 0.5 per cent) and total organic carbon (TOC) contents of greater than seven per cent. The single-addition NAG test will tend to overestimate acid potential in samples with little or no pyrite and high organic matter content, potentially leading to sample misclassification. High pyritic sulfur samples tend to show little difference in single-addition NAG acidities with increasing organic matter, and it appears that pyrite is preferentially oxidised by peroxide when present in significant concentrations (greater than one per cent pyritic S). In sequential NAG tests overestimation was greatest in samples with little or no pyrite, but highly carbonaceous (>20 per cent TOC) pyritic samples were affected in later stages as the pyrite was depleted. A modified NAG method is proposed to account for the relative proportions of pyrite derived acidity and organic acidity in a given NAG solution.

Jan 1, 2003

By F Jiao, J Wang

By the year 2000, China was the sixth largest gold producer in the world, with about one-quarter of total production being derived from refractory or semi-refractory deposits. Although bacterial oxidation plants had been previously tried in China using local technology, these plants had not been commercially successful. The Laizhou Gold Enterprise (Tarzan BioGold Co Ltd) located in Shandong Province, undertook to modernise their gold processing facility in 2000 with the introduction of Bacterial Oxidation (BACOX) Technology. In 1997 BacTech Australia and Mintek of South Africa had formed a technology partnership, combining forces in the provision of bioleach technology. Under a cooperation agreement, BacTech/Mintek were chosen as the preferred technology providers for this first application of commercially proven bacterial oxidation technology within China. The paper describes the successful operation of this plant over the last three years. The events of project implementation are described, from the metallurgical testing of concentrate; through to the commissioning at the design throughput of 100 tonnes per day resulting in 80 000 ounces (2.5 tonnes) per year of refined gold. Process aspects of the operation encountered over the last three years are discussed which illustrate the robustness of the operation. The success of the bioleach facility has led to an advancement of plans to double plant capacity and some of the innovations, which may be employed in this expansion phase, are discussed.

Jan 1, 2004

The resistance of lead to chemical attack and the ease of its fabrication has made it one of the most useful of the metals available to the chemical engineer and the electrometallurgist. It has proved to be of particular value in the manufacture of sulphuric acid, and since the conversion of the sulphur of pyritic ores into sulphuric acid is becoming the duty of the metallurgist, the corrosion resistance of this metal will be a matter of considerable interest to him from the standpoints of both producer and user. He realises that there is little to be gained in carrying the process of purification past the ordinary economic limit if little or nothing is to be added to its corrosion resistance, and he as user would not be willing to pay a premium for such purification if it can be shown that its reputed value has no scientific foundation.The metallurgist is well acquainted with the trouble and expense of meeting demands which have nothing torecommend them but prejudice and fancy. The valuable anti-corrosive properties of lead are very commonly ascribed to its forming insoluble compounds with the acids sulphuric, hydrochloric, carbonic, etc. If we trusted superficial visual evidence alone, such a view would receive strong support, but in the light of what we know of the mechanism of corrosion we must attribute its resistance to other factors much less obvious to casual inspection. Certainly there may be some mechanical obstruction set up to diffusion of the liquids towards the surface of the metal.

Jan 1, 1932

The purpose of any feasibility study is to determine whether a particular investment or management program will enhance shareholder wealth by, for example, producing an economic return in excess of the cost of equity capital.The threshold rate of return conventionally used in gold feasibility studies is higher than the cost of equity capital, meaning that some viable projects are wrongly described as being sub-economic with their development deferred.Is the industry failing to fully realise its potential? Aside from important technical considerations that determine the cost of exploiting inground inventories, feasibility studies need to incorporate expectations about future gold prices, exchange rates, interest rates and tax rates.Rather than revert to speculation, insights from capital markets give a rigorous framework in which these parameters can be determined for feasibility purposes. Separate questions sometimes, and then inadequately, addressed by feasibility studies include: ò Is it optimum? Many projects are expanded soon after project commissioning - what does this say about the quality of the initial feasibility study? Moreover, does the rate of extraction really matter? ò What is it worth? Although feasibility studies are designed to address viability rather than valuation, such studies are never- theless used by the industry as further evidence that the equity markets have got it wrong again! More likely the problem is with the financial slide rule being used. ò Can it be debt financed? The bankable feasibility study has entered the vocabulary of the gold mining industry but what does it mean? Does it matter anyway how the project is to be Financed?

Jan 1, 1991