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By Zervoudis J

Limitations of current touch-up solders for galvanised steel include coating thickness control problems and poor corrosion and abrasion resistance as well as health and environmental concerns due to toxic constituents such as lead. This paper reports on progress in ILZRO-sponsored research to develop an improved touch-up solder. Encouraging results were achieved in torch soldering trials with experimental zinc-tin-based alloys. Mouldability and coating thickness control were achieved over a practical working temperature range in which the solders consisted of a viscous mixture of solid primary zinc phase particles in a liquid zinc-tin eutectic matrix. The mouldability was dependent on the microstructure of the solder sticks, and optimum structures could be obtained through control of casting solidification rates and by the addition of small amounts of copper. Hardness, abrasion resistance, adhesion and corrosion tests on experimental Zn- (40 - 50 per cent) Sn-I per cent Cu also showed improved performance over lead-tin-zinc solders and compared the effects of tin content within this range. Atmospheric corrosion testing and optimisation of alloy composition and methods of solder stick production are continuing.

Jan 1, 1993

This paper describes the characteristics of blasting which set it apart from other methods of breaking rock. The mechanism of rock breakage and the influence of rock proper- ties are then discussed. The strain and fragmentation produced by a cylindrical charge does not change once the charge is longer than 16 blasthole diameters. The influence of bench geometry, charge length and drill diameter are then examined. It is shown that spherical charges have advantages over long slender cylindrical charges. By selection of the appropriate drill diameter, explosive and charge configuration the optimum blasting practice for a given rock to give suitable fragmentation and muckpile profile for sub- sequent handling can be found. The fragmentat- ion depends not only on rock and explosive properties but also on the pattern which dictates how effectively the cracking is utilised. The size distribution of the fragments is given by the Rosin - Rammler equation. Undesirable cracking of the rock in the final wall can be controlled by the careful design of blasts as they approach the final wall. Finally, it is concluded that because of the distance to which blasting can fracture and then displace rock it is suited for the breakage of large volumes of rock.

Jan 1, 1978

FINANCE FOR EXPLORATION Two factors have basic importance in relation to the availability of finance: the apparent success of continuing exploration activity and tax concessions. It is not proposed to discuss the effect of existing tax incentives, as these have already been outlined and are generally accepted as being reasonably attractive; certainly not a deterrent to possible investors. However, it is obvious that the greater the tax incentives, the greater the amount of money that will be attracted, and the wider the number of people who can be brought into the pool. If, as is suggested, the chance of discovery is related to expenditure and effort, then the more money attracted, the better the prospects of significant finds. It is probably correct to assume that the largest expenditure in mining will come from, or be induced by, people expert in the field, people who are fully aware of the risks and benefits and perhaps making conservative decisions because of this awareness. Insofar as the general public is concerned, while in the first burst of enthusiasm it will frequently follow any promoter, in the long run it too will become more sophisticated and will strongly support only those promoters and companies of good repute and proven record.

Jan 1, 1971

Before any accident prevention and total safety programme can succeed, a safety concientiousness or attitude needs to be implanted in the employees' minds. Psycholog- ical and physiological conditions play a vital role in accident causation and prevention. Both need attention in a good safety programme, but working place conditions and environment are more easily corrected. However, the challenge is to change attitudes in the minds of men - psychological factors in accidents. To do this does not require a Safety Officer, but does require a Safety Adviser. At Blackwater mine a Safety Adviser is available to all sections of the organisation to guide and assist, to provide data and material to use at meetings, to help in accident investi- gations and to help organise training. To eventually achieve total commitment requires every member of the management team to be a salesman towards all around selling an attitude to safe working, a way of life. At Blackwater mine the workforce is young overall with most employees being under 40 years old. Psychologically this is a quite different problem to a balanced ages working group. A great deal of effort is needed to communicate with the younger, articulate, better educated employee who is also generally a skilled operator in the capital intensive

Jan 1, 1975

A general approach to the analysis of processing technology is presented using the concepts of Process Aims, Process Characteris- tics and Process Costs. From an examination of the processes used in extractive metallurgy a hierarchy of process aims is identified, these aims are separation, compound formation,, metal production and metal purification. The application of this methodology to process flowsheet development is described.

Jan 1, 1984

By Batterham RJ

A 'research model' can be used to investigate cause and effect relations and generally improve the understanding of extractive metallurgical processes. As such, it is a useful research technique which complements the traditional methods of laboratory and plant measurement. The procedure of model development is iterative and involves observation of the process, hypothesis of phenomena, prediction using mathematical descriptions of the phenomena and comparison of predictions with real-world measurements. Lack of agreement of predictions with real-world measurements usually indicates an inadequacy in the hypotheses and necessitates revision. Experimentation has an integral role in the process of model development but its emphasis is different from that when experimentation alone is used to study processes. Since a process as a whole is investigated by using a model, experimentation is restricted to the study of specific phenomena to aid the description of these in the model, to the characterisation of the raw materials (for initial values of the model parameters) and to the measurement of physical and chemical constants required in the model equations. Similarly, plant measurements are made for the purpose of comparison with the model predictions not to establish cause and effect relations. This makes plant experimentation much simpler and cheaper'since most measurements-can be taken during normal operation.

Jan 1, 1984

The twin iron ore islands of Cockatoo and Koolan are located in the spectacular setting of Buccaneer Archipelago off the Kimberley coastline of WA.Cessation of ore shipments from Koolan in 1993 ended 42 years of continuous mining activity which began with the first shipment of ore from Cockatoo in 1951.

Jan 1, 1993

This paper outlines a range of strategies for steady state optimisation of most types of concentrators. Optimisation is considered in terms of comminution performance, energy efficiency, concentrator strategy and overall mine/concentrator operating philosophies. Application becomes more complex as the range of optimisation is expanded. However, the potential gains also increase. A step by step framework for data collection and analysis is provided. This process is facilitated by powerful simulation and mass balancing programs which are now in common use. Once a sound, steady state rationale for optimisation has been developed, it may be used to provide a fine foundation for process control system development.

Jan 1, 1993

The paper presents two methods for periodical identification of the dependence between haulage speed and loading torque of the shearer for periodical corrections of control algorithms. These algorithms are useful for working with small microprocessor-based systems. The paper is concluded with results of identification using above methodsand with discussion about their merits and demerits. The longwall mining system is the basic exploita-tion system used in coal mining in Poland. The quantity of coal produced by this system, using a shearer loader as a cutter-loader machine is esti-mated at 170 million tones per year. For this rea-son scientific research concerning these machines is of major practical significance.

Jan 1, 1985

Mineral resource classification is essential because it is required for public disclosure. The resources must be binned by a qualified person into measured, indicated and inferred categories using an appropriate methodology. The classification methodologies used have long been a topic of research and discussion. There are various traditional and geostatistical methods used in practice. Some are more popular than others. Because of the uniqueness of each ore deposit, it seems almost impossible to have a single industry-accepted norm for mineral resource classification. Therefore, some experts have adapted the methodologies tailored for the deposits they are working on, but many simply use the methods they and their clients understand and are comfortable with. In this paper, a new approach is presented to classify the mineral resources using a data geometry index. This index combines both traditional and geostatistical aspects of resource classification based on the data configuration around the block interpolated. It is a function of several variables such as kriging variance calculated for a block, distance from the block to the nearest sample and the average distance of all samples used to interpolate the block. Thus the approach using this index takes into account the spatial data configuration around the block being estimated, as well as the traditional distance criteria. The data geometry index and how it is calculated is explained. A case study for a gold deposit is presented to see how the classification based on this index compares to the existing methodology used in this deposit for mineral resource classification.

Sep 26, 2011

By Fee DJ

Some four hundred million tonnes of low rank sub-bituminous coal occurs in four separ rate lobes at Leigh Creek. These deposits are in a sparsely populated pastoral area remote from industrial centres. Early development was retarded because of high mining and haul- age costs and the availability of other fuels. The search for additional fuels after the second world war led to thorough investigations into the burning characte-,istics of the coal and the discovery of shallow coal suitable for open out mining. The development of the field included the establishment of water supply, improved rail facilities and a town.

Jan 1, 1975

Over the last 15 years the contract mining concept has developed into an integral part of the Australian mining industry. Today it is a $2 billion per annum industry with the potential to continue to grow at a rate of between ten and 20 per cent. Australian contract miners have also exported the concept overseas where growth prospects are unlimited. The industry today is at a cross-road where both contractors and mine owners must consider the current state of the contract mining industry and where it is heading. To look at the present and the future, it is necessary to look back at the history of contract mining and why it has developed. Current industry concerns can then be summarised and the areas that need to be considered to enable the industry to prosper, reviewed. The ultimate goal is to reach solutions with benefits to both the mining companies and the contractors.

Jan 1, 1996

This paper intends to give an insight into what is often considered to be a poor relation of the mining industry but is in fact an integral part of any community. Aggregate production accounts for more than half of the world production of minerals by weight. In New Zealand production of aggregates runs at around five tonnes per capita per year, making it a significant industry. The industry in this country is dominated by smaller operations close to the market due to the widespread population and relative abundance of aggregate. The Logan Point quarry is one of the largest quarries in the South Island with an annual production of around 250 000 tonnes. The market is mainly based around roading and building in the Dunedin area with some higher quality specialist aggregates being used allover Otago. The quarry has been owned and operated by Palmer and Son Ltd for 106 years with a fifth generation family member the current quarry manager.

Jan 1, 1992

Poor ground conditions associated with historical workings have presented significant challenges to the drilling of production downholes at the Sons of Gwalia Mine. The combination of foam and polymer drilling, the use of Aquacrete to drill through voids and the practice of lining completed holes has allowed downholes to be effectively drilled and blasted in delaminated ground.

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

At 11 p.m. on Tuesday, 24th July 1979, an explosion of methane gas in a three heading development panel at Appin Colliery resulted in the deaths of fourteen men. The explosion followed after or was asso- ciated with a changeover of the ventilation to achieve a central intake between two returns. Investigation by Inspectors was followed by separate Judicial and Coronial Inquiries. Investigational information aimed at understanding the circumstances of the ex- plosion was prepared for the Inquiries. Recommendations following the Judicial Inquiry have been adopted by the Department of Mineral Resources.

Jan 1, 1981

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

The Australian Mining Industry Council is the peak mining industry representative body in the country. It is wholly funded by its member companies which comprise all of the major Australian mining houses. AMIC represents companies invo

Jan 1, 1994

Mount Isa Mines operates Hewlett Packard 1000 computer systems for process control in its major mineral processing plants. To simplify control systems implementation, a process control software package has been developed. This package is now used at the Lead/Zinc Concentrator where the HP computer is interfaced to Foxboro Interspec/Spec 200 system and Honeywell TDC 2000 front-ends. The HP computer controls crushing, grinding, flotation and tailings disposal. This paper outlines the development of process control systems at Mount Isa Mines. The creation of the process control package is described and the reasons for its development highlighted. The application of the software package and the implementation of process control systems at the Lead/Zinc Concentrator is detailed.

Jan 1, 1978

By P J. Harris, D J. Bradshaw

Surface oxidation of sulfide minerals, such as that found in the regions of a sulfide ore body near the water table, can have a significant impact upon flotation. This theme has been explored for Merensky ore type sulfides where an ore containing pyrrhotite, pentlandite and chalcopyrite was thermally oxidised and the role of potential remedies investigated. Back-scattered scanning electron microscope images are presented showing the oxidation layer which formed in the mineral surfaces. These oxidation layers were depleted in both sulfur and iron with incorporated oxygen. Flotation recovery rapidly decreased with increasing oxidation, particularly after 27 days and reached a plateau after 50 days. Up to 27 days, this effect could be partially overcome with higher collector additions. Oxidation had more impact upon the finer size fractions, particularly for pyrrhotite. For more heavily surface oxidised samples, ultrasonic treatment prior to collector conditioning was found to improve flotation recoveries. This treatment had the greatest effect upon chalcopyrite particles. Sulfidisation was successful in restoring the flotation recovery of the heavily oxidised sulfide minerals. Longer sulfidisation conditioning times were not conducive to good flotation recoveries of both oxidised pyrrhotite and pentlandite due to oxidation of the freshly formed sulfide surfaces. For maximum flotation recoveries of oxidised pyrrhotite, pentlandite and chalcopyrite, different sulfidisation conditions are indicated. It appears likely that in a mineral processing operation treating oxidised Merensky type ores, two stages of sulfidisation employing different conditions would be required.

Jan 1, 2005