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By W T. Pate, A V. Potapov, J K. Lichter

Even though flotation is one of the most important unit operations of mineral processing, accurate modelling of this process for plant performance prediction has remained elusive. In the last four to five years dramatic changes have occurred in our ability to make credible model based predictions. This paper briefly traces the history of flotation modelling from simple (lumped pulp-froth) æchemical kinetic analogueÆ models for single cells to more detailed multi-phase, multi-component population balance models for banks of cells. It then focuses on recent developments in physics-based modelling tools. This includes current efforts to model the forces of attachment and detachment at the individual event level as well as multi-event levels in individual cells and circuits. Two examples of these tools are presented. The first is DEM modelling of the mechanics of motion of bubbles in froths. The second is population balance modelling of the dynamics of flotation circuits describing how they are influenced by upstream processes (such as crushing and grinding) as well as internal process variables (such as aeration, agitation and reagent addition). Applications of each of these tools are discussed.

Jan 1, 2005

The Australian lead-zinc industry faces a future in which the world market is likely to show at best only minimal growth and in which there will be increasing competition. Its production facilities use mature technologies employing expensive labour and increasingly costly energy in a country which demands the highest standards of environmental performance. Returns on investment are already unsatisfactory.Technology for survival would appear to indicate a need not only for more efficient capital, labour and energy usage combined with improved environmental performance, but also flexibility to handle more complex materials than the traditional, virtually single metal concentrates. This offers the potential for improved overall economics from the mine onwards, but will demand efficient separation and by-product recovery processes.In the lead industry these problems are being addressed in several emerging technologies. With zinc, the situation is less clear.

Jan 1, 1985

The ongoing need for improved fuel economy, longer engine life, reduced emissions and greater power output has driven the need for lower charge air temperatures. Cuamins will introduce a split loop, single water pump approach to low temperature aftercooling (LTA) in 1987 with the introduction of its 1492 kW (2000 BP) 16 cylinder K Series engine. The LTA system selection process considered performance, durability, fuel economy, and total engine installed cost. The split loop system selected takes full advantage of the engine cooling characteristics to provide optimum charge air temperatures at all speeds, loads and ambient temperatures. Computer simulations and engine tests were used to determine performance for each charge air cooling alternative. The split loop system chosen offers many advantages compared to the other alternative systems studied which included air-to-air and dual loop (two radiator, two water pump) systems.

Jan 1, 1986

The advantages of coordinate geometry in design and construction of underground works are apparent for reasons of flexibility, security, computer operations, survey error analysis, and the use of numerical techniques for setting out and checking works. Integration with National or State survey systems is useful in the long term, both at design, construction and future works stage. Equipment and methods are available which permit "absolute" monitoring of structures and strata over long periods,to close toler- ances. This work can be carried out in the limiting urban environment. Rapid data acquisition by semi-automatic devices, or photogrammetry, utilizing electronic data processing is capital inten- sive, but provides more data than analogue surveys (i.e., setting out centre lines) and becomes more attractive with increased labour Costs.

Jan 1, 1976

Petroleum exploration and development is vitally important for the future well being of Australia. The Australian petroleum exploration/development industry is alive but not so well. A combination of.:factors point to the industry requiring a much more mature effort in both short and longer-term planning to ensure greater success and effectiveness for petroleum discoveries and development. While many petroleum exploration companies are competently run, there are far too many which will be lucky to survive, even though their exploration areas are highly Prospective.

Jan 1, 1983

By O Tiili, A Dixon

Many minerals processing plants need to have greater efficiency in current times and optimise their process performance in order to maintain high profitability. This is even more so in the current economic climate. In the case of large flotation cells, such as TankCell«-300 with over 300 m3 active capacity, ensuring consistent operation and optimal flotation conditions is particularly critical, given the high impact on overall process and throughput of such cells. As there are fewer cells to control and monitor, there is also a lower initial capital cost for instrumentation - the requirements, however, are higher. Despite such compelling reasons, instrumentation and basic control in flotation cells has not changed much in recent years. The standard is still to use traditional feedback (PI algorithm) controls for slurry level and flotation air. A new advanced instrumentation and control package for large flotation cells has recently been developed by Outotec and has been installed at Macraes.In addition to the standard basic instrumentation and control, the new system at Macraes consists of a froth image analysis system, a froth velocity control, and a level control system which utilises adaptive feedforward compensation. There are three TankCell«-300 cells in operation at Macraes since November 2007 and the new control system was commissioned in December 2007.The paper will include comparative data from pre- and postsystem installation and discusses benefits including optimised recovery, improved performance, as well as ease of operation.

Jan 1, 2009

By J M. Dwyer, S Williamson

Acceptable post-closure performance of decommissioned mining operations is a critical factor in persuading todayÆs environmentally conscious public that the mining industry will not continue to burden future generations with the legacy of environmental tragedies. Post-closure impacts must be identified and managed through robust engineering design if the post-closure environment is to be environmentally sustainable. To manage potential post-closure risks (environmental, health, safety, social and economic) within acceptable limits, WMC incorporates a risk-based approach to closure planning and engineering design. WMCÆs risk-based closure engineering design process provides a simple methodology for developing robust closure plans û the process æengineers outÆ unacceptable risks and æengineers inÆ a sustainable post-closure environment. Benefits of the risk-based process include stakeholder endorsed closure criteria for an agreed post-closure land-use, focusing of resources on major risks, and a realistic and accurate estimate of the required closure provision. The outcome is an increased likelihood of satisfying the three pillar goals of sustainable development û a financially sound solution that poses a low risk to the environment and future generations.

Jan 1, 2003

By Denholm WT

The Dittmer process for the debismuthising of lead by electrolysis beneath molten caustic soda has been scaled up to 100 kg lots for batchwise operation and to 20 kg per hour for a continuous flow of lead. Bismuth was decreas- ed from 0.03 to less than 0.005 wt. per cent for an electricity consumption of 220 kWh per ton of lead. Lower bismuth levels may be readily achieved if required.

Jan 1, 1975

By Van Rensburg C S J

The options that are open to engineers for cooling mines are limited and are primarily dependent upon the thermophysical properties of coolants. These properties are carefully analysed in the context of cooling mines and a comparison is drawn among Ammonia (R717), Monochlorodifluoromethane' (R22), Dichlorodifluoromethane (R12) and Water (R718). From this comparison the extent of Ammonia's superiority as refrigerant is Evident.

Jan 1, 1988

By T Muri

The drying operation of materials from particulate solids, through slurries and suspensions, to continuous sheets represents an important part of several processes in the chemical and mineral industries. The increasing demand of high productivity at low cost and minimal environmental impact makes it complex to evaluate and choose the best available drying technology for each industrial application. The drying technologies are mainly characterised on the basis of how the wet product is related to the drying medium, namely: direct and indirect drying. In the direct drying method (convection drying), the product is brought into direct contact with the drying medium, which may be hot gas or air. Large quantities of gas are necessary for transfer of the required energy. A special case of the direct dryer is the fluid bed dryer, in which the product floats on a cushion of air or gas. The process air is supplied to the bed through a perforated distributor plate and flows through the bed of solids at a velocity sufficient to support the weight of particles. Very high heat and mass transfer values are obtained as a result of the intimate contact with the solids and the relative velocities between individual particles and the fluidising gas. In the indirect drying method (conduction or contact drying), the wet product is separated from the drying medium. The drying unit can consist of a rotor forming the indirect contact heating surface mounted in a stationary or rotating shell. The indirect method uses saturated or superheated steam resulting in low energy consumption and minimal environmental impact. In this paper, a review is given of the technologies available on the market based on different drying methods. The advantages and the disadvantages are summarised with respect to issues such as investment and operating cost, maintenance, product capacity, product handling and environmental impact.

Jan 1, 2006

By Morrison J

Considerable confusion is to be found in the methods of estimating mineral reserves. The solution appears to be more cooperation between industry and government to agree upon a classification system with guidelines to overcome the problem of the many variable factors affecting reserves. The classification system proposed by the United States Bureau of Mines and the United States Geological Survey (USBM/USGS) together with the guidelines similar to those suggested by the Australasian Institute of Mining and Metallurgy/Australian Mining Industry Council (AusIMM/AMIC) is recommended for reporting mineral reserves to government.

Jan 1, 1979

Modern Management Systems for Higher Margins By Malcolm Roberts, Catalyst for Corporate Performance Ltd Malcolm Roberts put the case for changing systems in order to change behaviours and attitudes and improve productivity. ""The key to lifting margins is changing systems."" A system is anything that drives ways of doing things. Sometimes these are formal, and documented, and sometimes they are not. Improving productivity The way to dramatically improve performance is to use the systems. Roberts stressed that if systems and processes are under control, the benefits of automation are huge. If they are not, the benefit of automation will be lost. To improve productivity, you need to: ò identify what to change in the process, ò use the proven methodology to systematically improve the process, and ò change what people do - change work practices.

Jan 1, 1997

Extensive infrastructure construction works were required for the development of the underground and open-cut coal mine at Ulan to a production capacity of 5 million tonnes of steaming coal per annum. The Ulan Mine development project was constructed in a two year period at a cost of $240 million. The infrastructure component included the construction of the mine site building works, civil works and 150km of railway, valued at $105 million. These works were successfully completed under a construction management agreement within two years. The separate elements of the project are described in detail in the paper.

Jan 1, 1983

Diversity is a key strength for Western Mining Corporation. An international corporation with assets of about $A10 billion, WMC is engaged in both mining and downstream processing of minerals including nickel, gold, alumina, copper and talc, as well as having interests in oil and gas production and agricultural fertiliser. The company is focusing on several core commodities that will maintain its strength in the years ahead. Although most current mineral assets are within Australia, it plans to have 25 per cent of its operations off-shore by the turn of the century, and be a major producer in at least six core commodities. WMC's strategic and management focus has shifted from a regional approach to a commodity focus so that it can more readily cater for different markets with differing sensitivities. This document is an ABSTRACT ONLY - no paper was published for this presentation

Jan 1, 1996

IF lead be heated with concentrated sulphuric acid two distinct actions will usually be observed. In the first, bubbles begin to be evolved more or less rapidly from the lead, and in the second, which occurs at a higher temperature than the first, hydrogen and sulphur dioxide are evolved, free sulphur is liberated, and leadsulphate is formed. The second action may be violent and usually continues till the lead is all consumed.Attempts have been made to apply these reactions, by means of a standard procedure, as a "Flash test" for the acid resisting qualities of chemical sheet lead. The purpose of this article is to comment on the best method of performing the test, on the various phenomena which may be observed during the course of it and on the interpretation of the results when obtained.PREVIOUS WORKIn 1919, Barr...

Jan 1, 1930

I know the theme of the Congress is "The 21st Century - Mining for Mankind" but I hope you will understand why my address touches upon some near-term issues as well. With the world oil market the way it is at present, "the long term" seems to be next week and no one is even sure what will happen tomorrow! So I am going to take a little licence with the theme of the Congress and talk about some fundamental issues that have much to do with the current uncertainties. The ways in which these issues are resolved and the role governments elect to play in the next few years will determine both the shape of the petroleum industry in the 1990s and beyond and the success with which we can confront a growing and inevitable future dependence on OPEC oil resources. But just in case you are not familiar with what has been happening in the petroleum industry recently and why the future seems more uncertain than ever, let me show you the gyrations in oil prices over the past 13 years, and remember that it is only another 13 years or so years to the 21st Century.

Jan 1, 1986

By Seshold P

The cost of capital is the rate at which a project's cash flow should be discounted to obtain the Net Present Value. The cost of capital is a weighted average of both debt and equity funds of a company, on an after tax basis. Two methods are described for calculating a company's cost of equity, the Dividend Valu- ation Model and, more importantly, the Capital Asset Pricing Model. A worked example is presented where the cost of capital was obtain- ed for two resource companies. The application of the cost of capital was illustrated by way of a mining equipment replacement problem. The paper outlines refinements and problems that may be encountered with the use of the cost of capital, and concludes that it is an integral part of any project evaluation.

Jan 1, 1983

By Westcott PC

The development of a coal project must pass through a number of phases, taking it from a preliminary evaluation through to detailed mine planning. For each phase the cost of data acquisition and associated mining studies increases exponentially for linear improvement in confidence levels. Within each mine planning phase there are four main activities. These are the economic ordering of reserves, the development of optimum mining strategies, mine design and scheduling and finally the estimation and analysis of costs. The development of the optimum mining strategy is one of the most critical aspects of a mining evaluation and the application of economic criteria at this stage of the project is vital to the successful generation of an optimised mine design. A recommended method is the concept of Economic Ratio (ER) which expresses the likely cost of mining from a given location in a deposit in terms of the value of the product likely to be recovered. The most economic mining strategy will be to mine areas from low economic ratio to high economic ratio within the constraints of reasonable equipment application. When selecting equipment a particular machine should not be selected solely on comparison with other machines in isolation, but the total application must be analysed. In the final selection the decision should be based on whether or not it has a beneficial effect on overall project economics. The economic assessment must take into account the time value of money, so the real cost can be determined with adequate provision for capital and operating costs over different time spans.

Jan 1, 1983

This paper looks at the development in management education for engineers at the undergraduate level with particular reference to mining engineers. The management core content of the engineering degree course at Ballarat C.A.E. is described is some Detail.

Jan 1, 1986

This paper looks at the development in management education for engineers at the undergraduate level with particular reference to mining engineers. The management core content of the engineering degree course at Ballarat C.A.E. is described is some Detail.

Jan 1, 1986