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In recent decades the awareness of environmental issues by the general public has developed at an accelerat- ing rate. This is the result of a number of factors including more scientific knowledge of environments and of the impacts of modern society upon them, higher levels of education, the opportunity for people to travel more, and the success of the various communication media in bringing in- formation to the communities of the world about such environmental crises or threats as the smogs of Los Angeles and London, the Torrey Canyon and Santa Barbara oilspills, Minamata disease in Japan, the spread of the Crown of Thorns starfish, the disposal of toxic industrial wastes into the Upper Rhine, the discovery of high mercury and zinc contents in marine foods in southern Australian waters, and the proposal to mine limestone at Precipitous Bluff in Tasmania.

Jan 1, 1975

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

By Gadd D. E

Since October 1972, New Zealand Steel Mining Ltd has loaded around 10 million tonnes of ironsand concentrate from single-point mooring buoys located off-shore at Taharoa on the west coast of the North Island of New Zealand. Before the first off-shore loading system was installed a considerable research effort was applied to proving the slurry loading technique. Subsequently the system has been expanded and a new buoy, pipelines and pumping system were installed in early 1978. Since then 110,000 DWT class ore carriers have been loaded at rates of around 2600 tonnes per hour through twin submarine pipelines. This paper reviews the operation of the shiploading system and attempts to answer the question: "If the Taharoa operation were to be planned in 1980, would the same research spending be necessary or have published research results since, made such practical tests unnecessary?".

Jan 1, 1980

The theme of the conference this year is diversification. One way to diversify is through acquisition. The principle underlying the winner's curse is that in competitive bidding situations where the value of the asset bid for is uncertain the winning bid will overstate the true value of the asset. The successful bidder is blessed with the winner's curse. What this paper will explore is to what extent this is true; how acquirers can avoid being blessed with the winners curse; and show how joint venture deal structures are used within the mining industry to avoid the winners curse.

Jan 1, 1996

By Kohra A, Shoji S

The amount of copper production by flash smelting process occupies about 17% (equivalent to 1.4 million t/year) of total free world production. In Japan, 650,000 tons of copper is produced annually by flash smelting. This is 65% of the gross copper production of Japan. To reinforce pollution control, promote energy saving, and enhance production efficiency by increasing the size of furnaces, conventional blast furnaces and reverberatory furnaces are being replaced with the flash smelters worldwide. The Ashio Smelter started copper production in 1884 and developed in association with the Ashio mine. In those days, the Ashio smelter produced copper by using the blast furnace process designed for the high-grade ore from the copper mine. At that time, this process was specialized in Japan. In 1956, for the first time in Japan, the Ashio Smelter introduced the flash smelting process developed by Outokumpu Oy of Finland (it is suitable for treating the copper concentrate, producing sulfuric acid and improving production efficiency). The flash furnace in Ashio, the first ever in Japan, had a capacity of 230 t/day for copper concentrate and was operated up to 1962. During this period, various operational troubles were solved, and further improvements were made; and, in 1962, a Furukawa-type flash smelting furnace was completed in Ashio. This improved version of a flash furnace had a capacity of 450 t/day. There was one flash furnace and one waste heat boiler, which were arranged in a unique pattern for that time. This furnace may be said to be the prototype of the present flash smelting process in the world.

Jan 1, 1987

Access to secure and reliable water resources is fundamental to the minerals industry. In recognition of that requirement, and cognisant of extensive contemporary public water debate and reform initiatives in Australia, the Minerals Council of Australia (MCA) approached the Ministerial Council on Mineral and Petroleum Resources (MCMPR) proposing the establishment of a Joint Working Group to prepare a framework of strategic principles to ensure responsible water management at a site and corporate level, manage risks and identify opportunities. The Framework provides high-level guidance on issues that should be addressed in water decision making across Australia in relation to mining and associated processing operations. It identifies principles and objectives for adoption in four areas, viz: valuing water, strategic water planning, implementation, and engaging stakeholders. Given the high level nature of the Framework, and its national application, it does not seek to replicate detailed guidelines already widely available in each state and territory on operational water management practices and associated regulatory issues at mine sites. The Framework includes a series of case studies from across Australia that demonstrate where strategic thinking, wise water management and close consultation with stakeholders has delivered better water use, more profitable operations and excellent community/stakeholder relationships. The Framework was formally launched on behalf of MCMPR by the Western Australian Minister for Resources at the MCAÆs Sustainable Development Conference in Perth in October 2006. No full paper available for this extended abstract

Jan 1, 2006

The latent conditions clause in various general conditions of contract have traditionally proved to be a source of significant disputes in tunnelling contracts, even when extensive geotechnical investigations have been carried out at the tunnel site and a report of these investigations provided with the tender documents, informing the contractor of the nature and extent of subsurface conditions likely to be met with during execution of the works. This paper discusses the contractual aspects of the new latent conditions clause in the recent Australian Standard AS 2124-1986, General Conditions of Contract, in relation to tunnelling contracts. A comparison of this new clause is made with other latent conditions clauses in general conditions of contract in use in Australia and other commonwealth countries. It is seen that the new latent conditions clause in the recent Australian Standard 2124-1986 has, by providing for a reasonable apportionment of risks, attempted to minimize contractual disputes relating to latent conditions in tunnelling contracts and to provide a satisfactory basis for quick and efficient settlement of such disputes should they arise during execution of these contracts.

Jan 1, 1987

By D J. Williams, G W. Wilson, S, A B. Tran

A comprehensive field program was implemented to evaluate the internal structure and hydrology of two full-scale waste rock piles. The excavation of waste rock dumps for in-pit disposal at the two mine sites provided an opportunity to characterise the in situ properties of the dumps given contrasting geologic and climatic settings. The internal structure and materials within the dumps were observed and sampled as the waste rock piles were being excavated and placed in the open pits for permanent closure. The field program was designed to fully characterise the structure and material properties of the waste rock. The alteration of the material by physical and chemical weathering was also observed. Samples were analysed for paste pH, water content, grain size distribution and geochemistry. In situ density and matric suction were also measured. Soil water characteristic curves and saturated hydraulic conductivity were measured for representative materials. These properties were used to predict seepage pathways through the waste rock and the resulting outflow geochemistry using the finite element model SEEP/W. The materials in the dump at Site 1 were predominantly fine-grained in texture and highly weathered. The presence of dipping beds with alternating coarse and fine materials was evident throughout the profile of the dump. The structure of the waste rock appears to have an impact on the hydrologic pathways within the waste rock pile. The material in the dump at Site 2 was found to be competent and resistant to particle size breakdown. The particles range in size from clay size to large boulders with the median particle size being approximately 125 mm in diameter. The coarse-grained texture of the waste rock resulted in a loosely packed arrangement of coarse particles with little matrix material infilling the pore spaces between the coarse-grained particles. Seepage modelling for Site 1 was completed to predict seepage paths based on observed structure and hydraulic properties measured in the laboratory. The modelling showed that materials with a fine grain size distribution become the dominant pathways for flow through the waste rock pile. The modelling also showed that layers with high silt and sand contents are subject to the highest flow rates. Finer grained clay rich layers have a low hydraulic conductivity and do not convey large volumes of water. Alternately, coarse gravel and cobble materials are unsaturated under values of matric suction that approach the residual water content of the material and do not transmit liquid water. The seepage modelling together with the results of the geochemical analysis show that the dominant particle size that receives the most fluid flow and flushing ranges from fine sand to silt, corresponding to materials with air entry values ranging between 5 kPa to 50 kPa.

Jan 1, 2003

This paper summarises some observations regarding the way SAG and AG mills work based on the last ten years of pilot plant operation, grinding circuit design and operational reviews for various projects in Australia and overseas. The main purpose is to promote discussion on key factors influencing breakage in a SAG mill. The focus of the paper is on two questions: How do mill lifters and liners really work and have an effect on grinding? How does the mill charge composition impact on grinding performance? The focus of the paper is on observations of mill behaviour in both pilot plant trials and plant operation, particularly on Cadia ore. DEM, by others, and JKSimMet modelling of SAG mill performance have greatly assisted in forming the ideas expressed in the paper and both are valuable tools in developing our understanding of the comminution process. Put in the æextremeÆ form the major observations and conclusions expressed in this paper are that: the main purpose of mill lifters is to reduce mill liner wear and not to promote rock breakage; the often promoted theory that balls impacting the ætoe of the chargeÆ is a dominant form of breakage is incorrect; and fines production in a SAG mill is primarily a function of the rock load mass, with a secondary dependence on ball load for any given circuit configuration.

Jan 1, 2007

By P Krauss, S Harpalani

Methane emitted from underground coal mines, along with ventilation air and known as ventilation air methane (VAM), constitutes the largest component of coal mine methane (CMM) emissions. Atmospheric methane, on the other hand, is a potent greenhouse gas with a significant adverse impact on the atmosphere. This has led to the development of various technological alternatives for its use as an energy fuel. Techniques involving oxidation of VAM, usually consisting of very low concentrations of methane, have been validated in the past. Prominent among these technologies are the thermal and catalytic flow reversal reactors, ancillary fuel technologies, lean fuel gas turbines, and concentrators and gasifiers. However, the efficiency of any VAM utilisation technique depends on the amount and concentration of methane in the ventilation exhaust air. Therefore, quantification of VAM emission from a coal mine is the first step towards identifying the most suitable technology for its utilisation for energy production. This paper presents an evaluation of the efficacy of VAM as an energy source. It provides details of a case study aimed at developing a technique to accurately quantify VAM emission from a coal mine. It further discusses the various VAM utilisation techniques available, and presents an economic evaluation of the alternatives. Based on the findings of the study, the most feasible method for VAM utilisation is identified for the mine. The paper summarises the procedure for quantifying VAM emissions and selecting the most suitable utilisation technique.

Jan 1, 2005

By J Manuel, N Ware

Ideal iron ore sinter is produced by optimising the balance between coarse (+2 mm), stable ore nuclei and a reactive matrix consisting largely of fluxed -1 mm fines. The authors have previously published work evaluating the matrix melting behaviour of a number of fine ores, using techniques developed by CSIRO. The focus of that work was to demonstrate the contribution of the matrix to overall sinter quality, with the results showing a direct correlation between melting point, matrix porosity and strength. CSIRO has also developed a complementary test to study the behaviour of coarse ore nucleus particles in contact with the sinter matrix and provide an evaluation of their reaction and assimilation properties. This test provides valuable fundamental information that can be used to better understand the role of specific ore types and optimise blend composition.The CSIRO laboratory-scale assimilation test is carried out by embedding particles of ores of specific sizes into a fluxed matrix of known sinter blend composition, using real ores and fluxes, in a laboratory test that directly relates to pot-grate and plant sintering conditions. Samples are fired under controlled conditions in a tube furnace using a standard heating profile and a constant, low-oxygen potential atmosphere. These conditions simulate the actual sintering process while removing the effects of the many locally-variable parameters (eg temperature, oxidation potential and localised chemistry) that exist in the actual process, meaning that trends in behaviour can be more clearly seen. Designed as a compromise between the industry-standard pot-grate sintering test and a more fundamental test using chemical reagents, the aim is to isolate and evaluate the nucleus behaviour of an individual blend component to allow an improved understanding of the role that an individual ore plays in a specific blend. Measured cross-sections of the resulting fired samples provide a semi-quantitative measure of reactivity, while accompanying photomicrographs allow a qualitative assessment of assimilation properties (eg volume and distribution of secondary porosity generated during reaction).In this paper, to complement the previous work published on melting behaviour, nucleus particles were selected from hematite, hematite-goethite and goethite ores and embedded in a simulated plant sinter matrix. Drilled core particles of two sizes were tested at fixed temperatures simulating low- (<1300°C) and high-temperature (>1300°C) sintering conditions. The resulting assimilation properties are compared and discussed as a function of particle size, temperature and ore/sinter mineralogy. The implications for the contribution of each component to the prediction of blend sinter quality are also discussed.CITATION:Ware, N and Manuel, J, 2015. Fundamental nucleus assimilation behaviour of hematite- and goethite-containing ores in iron ore sintering, in Proceedings Iron Ore 2015, pp 77–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By C Zhang, G Si, J Oh, X Zhu

The presence of rock joints has a huge impact on the strength, deformability, and permeability of fractured rock masses by providing surfaces of weakness on which further deformation are more prone to occur, and by serving as the major channels of water flow due to low matrix permeability. In earlier studies, water flow-through rock joints is often assumed as laminar flow between two ideal smooth parallel plates, and the well-known cubic law was derived and widely used to characterise the hydraulic behaviour of rock joints. However, natural rock fractures are irregular and of spatially varied aperture. Thus, the concept of equivalent hydraulic aperture was introduced to modify the cubic law. Numerous works have been conducted on the relation between hydraulic aperture and mechanical aperture incorporating various geometrical parameters. The surface roughness is one of the most sensitive factors for water flow-through rock joints. The aperture distributions are irregular in natural roughed fractures relative to the parallel plates. Barton et al (1985) and Olsson and Barton (2001) incorporated the joint roughness coefficient JRC in evaluating hydraulic aperture and proposed an empirical equation based on fluid flow tests. However, their equations do not conform to the dimensional consistency. Many other researchers (Zimmerman and Bodvarsson, 1996; Xiong et al, 2011; Li et al, 2019) considered aperture distributions in their equations. But the aperture distributions change during shear was always neglected. The contact of rock joints also has a significant impact on the hydro-mechanical behaviour of rock joint, since fluid tends to flow-through a rough joint along connected channels while bypassing the contact obstacles with tortuosity. Nonetheless, previous research mostly considered joint roughness or aperture changes based on 2D joint profiles, while the contact and tortuosity based on 3D surfaces were often overlooked. Only a few works have been made on quantifying the effect of contact area on flow behaviour (Walsh, 1981; Zimmerman et al, 1992; Zimmerman and Bodvarsson, 1996; Yeo, 2001), and mostly ignored contact area change induced by shearing and the associated impact on flow behaviour. Summarily, the quantification of fracture geometry effects on water flow in single rock joints still needs further investigation, especially when considering coupled shear-flow processes. This paper, therefore, aims to study the impacts of contact area and aperture distributions of the single rock joint on the flow behaviour. The evolutions of contact area and aperture distributions induced by shear are considered. Then, an improved model for estimating the hydraulic aperture with the mechanical aperture incorporating the above factors is developed. Finally, a series of shear and shear-flow tests are conducted on artificial joint samples and the model performance is verified by comparing against the results of experimental tests.

Nov 29, 2022

By Whiten W. J

Data from ball mills of a wide range of sizes are analysed using detailed mathematical models and non-linear least squares fitting techniques. In this way model parameters are obtained describing the behaviour of ball mills over a wide range of mill sizes and operating conditions. These parameters define the flow and breakage of each size fraction of ore in the mill. Flow of coarse particles through the mill is found to depend on the proportion of coarse particles present. The breakage rates of coarse particles are found to decrease markedly with mill diameter for mills over 3 m in diameter.Simulation of grinding circuit throughput at constant productsizing for different mill diameters shows that throughput is proportional to theoretical mill power consumption for mills up to about 3 m in diameter. Thereafter the throughput gradually falls below that indicated by power consumption, the decrease becoming quite significant for large diameter mills. Simple qualitative physical arguments are presented to explain this behaviour. The models developed have applications to ball mill scale up. Work on their further development is continuing.

Jan 1, 1982

By M W Kearns

The ERA - Ranger Mine ore processing operation consists of a sulphuric acid leach followed by counter current decantation and solvent extraction circuits. The most expensive unit processing operation at Ranger is the sulphuric acid leach. In 1992 and 1993 changes were made to the operation of the leach circuit. These changes have reduced power and reagent consumption in leach by 30 per cent and 20 per cent respectively with minimal effect on extraction efficiency. The first change was to operate the leach circuits at higher pHs than previously attempted. In addition a cap was placed on the amount of acid added to the leach circuit. Secondly, an on-line pH measurement system was installed and has reduced the variation with time of the leach circuit pHs. Finally, the number of leach vessels used was reduced from ten to seven. This action was undertaken after an examination of the uranium profile and the residence time in the leach circuit from previous years. This paper examines the above changes and assesses their effectiveness on plant performance and costs.

Jan 1, 1994

By Williams P

The assumptions made in conventional (Terzaghi) consolidation theory are not met in a tailings deposit. Finite or large strain consolidation theory must be employed. The paper describes such a consolidation model and its application to the design of tailings impoundments, water management systems, and long term rehabilitation.

Jan 1, 1990

By Yamada K, Abe H

Magnetic scanning type mass spectrometers have been given improved sensitivity with a large dynamic range and considerable resolution by the addition of a computer-controlled electric equipment. A mass spectrometer equipped with this newly developed electric system was applied to studies of the activities of liquid iron-silicon alloys and of liquid iron-phosphorus alloys at 1600¦C. The range of silicon concentration was 5.8at%-51.1 Si= at%, and values of ySi -3.1+0.15 and es 11.5 +1.5 were obtained. The concentration range of phosphorus was 1.3at%-5.7at% and a value of eP=7.3+0.1 was obtained.

Jan 1, 1980

By P Barrette

The manual gravimetric drying moisture determination methods currently employed by most mineral processing plants fail to provide timely and accurate information required for automatic control. The costs associated with transporting and handling concentrates represent a major portion of the overall treatment price. When considering the cash flow of a mining operation that is governed by both the smelter contract, with moisture penalties and the quantity and quality of the concentrates shipped, any tool that provides real-time feedback on the process is vital (Edwards, RP 1994). The introduction of an on-line moisture sensor would become a welcome addition to the process control field instrumentation package now applied. A novel on-line determination system for ore concentrate moisture content would replace the tedious manual procedure. Since the introduction of microelectronic-based control systems, operators have strived to reduce the treatment costs to the minimum. Therefore a representative and timely determination of on-line moisture content becomes vital for control set points and timely feedback. Reliable sensors have long been on the æwish listÆ of mineral processors since the problem has always been that you can only control what you can measure, (Konigsmann, 1990). Today, the task of moisture determination is still done by the classical technique of loss in weight utilising uncontrolled procedures. These same methods were introduced in the earliest base metal concentrators. Generally, it is acceptable to have ore concentrate moisture content vary within a range of seven to nine percent, but controlling the moisture content below eight percent is a difficult task with a manually controlled system. Many times, delays in manually achieving reliable feedback of the moisture content results in the moisture varying from five to twelve percent before corrective actions can be made. This paper first reviews the traditional and widely available methods for determining moisture content in granular materials by applying physical principals and properties to measure moisture content. All methods are in some form affected when employed on mineral ore concentrates. This paper introduces and describes a unique and promising novel on-line moisture sensor employed for mineral processing de-watering applications, which not only automates the tedious tasks but also results in reliable moisture feedback that can be used in the optimisation of the de-watering process equipment such as pressure or vacuum filters and fuel-fired driers. Finally, two measurement applications will be presented to indicate the usefulness and to summarise the measurement requirements for the proposed method of employing drag force and mechanical properties of the material itself to determine the moisture content. The commercial model of the equipment is described with the features and benefits to the users summarised.

Jan 1, 2003

In the face of intense global competition and other business pressures on coal miners, ongoing quality initiatives and continuous process improvements are needed to enhance business performance. By viewing a minesite in terms of key processes, rather then departments, and employing innovative technologies and better applying organisational resources, there exists enormous potential to achieve reductions in process cost and time.

Jan 1, 1998

By Owen D

A central part of mine planning is to ensure the protection of the beneficial uses of water. Integrated mining software does not generally provide tools to help the mining engineer to achieve this objective. This paper identifies some of the requirements which are desirable for such a tool and discusses how object oriented modelling can help achieve an effective design.

Jan 1, 1995

By Szymanski J, Planeta S

For many hard rock mines with near surface deposits, the surface crown pillars form the first line of protection for the immediate underground workings. Underground stopes are typically contained by crown pillar, which protects the level above, rib pillars, and a sill pillar through which the ore collection system is cut. This paper discusses the mining of these pillars, with particular emphasis on the overall stability of the mined out upper part of the mine areas. An area of interest is located in the Canadian Shield, where the mining has progressed below four thousand foot level in the ultramafic high grade sulphide type of orebody.

Jan 1, 1995