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A new two-metre column self-heating test procedure has been developed at the University of Queensland, which clearly shows the hot spot development phases that take place in bulk coal self-heating. The column results provide a more reliable indication of the self-heating propensity of coal than small-scale index tests. At the same time, off-gas evolution patterns associated with hot spot development are obtained, including the recognition of hydrogen evolution from oxidation at temperatures less than 80¦C. Subtle differences in off-gas evolution from self-heating between gassy and gas-drained coal are also apparent. This new approach to coal self-heating assessment offers an opportunity to further the understanding of the complexities of spontaneous combustion and will enable more accurate risk assessment for the coal industry.

Jan 1, 2005

With the exeption of the United States, Canada and Russia, oil has not been around in quantity near world centres of population. Production: in Western Europe is insignificant. Japan is without production as are Australia, Southern Africa, India; Brazil, Chile, New Zealand and China. The United States is, however, a large importer of crude oil. The very fact that oil is produced generally away from centres of population means that it has to be carried by sea to the area in which it is required. There is, therefore, a constant flow of oil around the world in very definite channels.

Jan 1, 1962

By K H. Esbensen

During the next five years Denmark will implement a significant reduction in the national CO2 emissions to fulfil the Kyoto Protocol. The energy sector is central for achieving this goal and extensive use of renewable energy is the most important single factor contributing to reduce emissions of greenhouse gases. DenmarkÆs renewable energy sources comprise wind energy and biomass. Wood chips and straw are the dominant type of biomass in Denmark. More than 500 000 tons of wood chips are used annually, currently with rapidly growth prospects. This contribution focuses on sampling of wood chips.

Jan 1, 2005

An integrated approach to risk management to complement insurance is the sustainable way forward for the modem organisation. For risk management to work, its various aspects need to operate interactively, not in isolation from insurance. This is the approach recommended in this paper. The risk management process is a strategic method for reducing an organisation's total cost of risk. Well established and basic risk management techniques will help identify and achieve risk management Objectives.

Jan 1, 1994

By M Warren

The professional geologist or engineer on a mining operation has a particular view of their operation. This is based on the factors of the operation that have a direct impact on the daily work program of the professional, such as production rates and grades. The view that would be taken by a financier who is called upon to support the project may be somewhat different. The value of the operation to the financier is in its ability to generate surplus cash for its owners and thus repay the debts to the financiers, with as low risks profile as possible. A number of tools are used to test the sensitivity of the project to variations in the key cost/revenue drivers. The Financier may call on a team of technical specialists to assist with the assessment of the cash flow and risk profile and to monitor the development of the project. The ability to offset this risk, as all projects have some degree of risk, may be a key factor in determining the level of financial support to be offered.

Jan 1, 2002

By Morris A. E

The thermodynamically-based pyrometallurgical simulation software STEPSOL (Version 3.0) provides for the modelling of activities using the Interaction Parameter Model, the Regular Solution Model, the Sub-Regular Three Suffix Margules Model, the Sub-Regular Four Suffix Margules Model and various simpler polynomial models. These are briefly reviewed, along with the major sources of data available in the literature, and the implementation of the models in the program.

Jan 1, 1992

More than in any other way, the community judges the minerals industry by its environmental performance. Minerals Council of Australia web site www.minerals.org.au/media/code Time is overtaking us. What was good enough yesterday is not good enough today. What may be acceptable today wonÆt be tomorrow. So we need to leap forward. We need to begin to move towards sustainability. Dick Zandee, Managing Director, Placer Dome Asia Pacific The competition for access to exploration and mining opportunities is intense. So is competition for the best people, capital and community support. Poor environmental performance damages a companyÆs ability to attract these. Quite simply, good environmental management is good business. Hugh M Morgan AO,Chief Executive Officer,WMC Limited. Decisions made by private industry and international corporations are increasingly determining the fate of the environment. ...Nothing could be more shortsighted than for todayÆs conservationists to neglect cooperation with business and industry as a means of moving company philosophy and public accountability ahead in favour of the environment. Dr Claude Martin,Director General,WWF International The four quotes above well illustrate the challenges faced by companies and conservationists in attempting to achieve the societal goal of sustainable development. That this aspirational goal itself is far from clearly defined, although it has been widely accepted and endorsed by governments, business and civil society, exacerbates the challenges. Sustainable development has as its central thesis the integration of environmental, social and economic policy. Its attainment by business has been described John Elkington (1998) as the pursuit of the ætriple bottom lineÆ - the achievement of social and environmental targets, in addition to the traditional economic bottom line. It is self-evident that business is both competent and comfortable defining and measuring economic performance and reporting that performance to internal and external audiences. As long as information has been prepared according to the established standards of measurement and reporting of economic performance, all audiences can have confidence in its accuracy. Business does not enjoy the same competence and comfort with regard to social and environmental performance. This is no startling condemnation of business, any more than it is a criticism of governments, non-government organisations (NGOs) or academia. It is a statement of fact that the tools to allow for credible definition and reporting against the other two components of the ætriple bottom lineÆ have yet to be fully developed and are, therefore, far from being widely accepted. Crucial to achieving sustainability is the ability to measure progress toward the goal. The task is to develop means to define appropriate performance standards and to credibly measure and report company environmental and social performance against those standards.

Jan 1, 2000

An automatic control system of a longwall roof support is dis-cussed. Hydraulic automatic control systems for longwall roof support have not met all requirements for such systems. Utilization of standard hydraulic elements to form a system that would-comply with all demands leads to a very complicated structure with a large number of hydraulic hoses within and between adjacent supports. So, only simplified systems have been made. This paper describes the multifunctional valve that per-mits realization of any desired logic functions, while maintaining a com-pact form, and analyses its application as a fully hydraulic automatic control system of a roof support.

Jan 1, 1985

By K Heiskanen

Flotation is affected by several factors, part of which depends on the mineralogical characteristics of the ore and part on process variables. Sulfide Ni-Cu ores occur typically in mafic and ultramafic igneous rocks. Serpentine minerals are also common. As a consequence of metamorphosis, sulfides and secondary minerals may be finely disseminated in an altered ore matrix. The floatability of minerals depends also on process variables. Oxidation of sulfide particles, process iron and dissolved ions in process water affect the behaviour of sulfides. The effects of some essential factors on flotation of Ni-Cu ores are considered.

Jan 1, 2005

By S C. Barrie

St BarbaraÆs Marvel Loch operations have successfully used longhole open stoping as the primary mining method for a number of years. A transition to Core and Shell mining was implemented in 2009 to recover substantial ore grade resources remaining in sill and rib pillars. The transition to core and shell for the Exhibition lode required continuous waste filling of created voids and thus the removal of the crown pillar at the base of the Exhibition pit by blasting. Access to the top of pillar was denied as the pit was partially rock filled with waste rock from underground development.Beyond the technical challenges of the blasting project, a simple and transparent risk management process was developed to ensure appropriate controls and mitigating strategies were in place to minimise risk to personnel during the pillar removal process.Although failure of the crown pillar was anticipated but with the actual timing unknown, on 25 December 2011 the crown pillar yielded during normal mine operations. Engineered and isolation controls in place at the time were of a sufficiently high standard to ensure limited exposure of the underground workforce and minimal damage to mine infrastructure. Successful risk management through implementation of appropriate controls during the project lifecycle of two years and three months proved to be fundamental to the safe removal of the crown pillar.CITATION:Barrie, S C, 2012. Successful risk management through project life cycle for removal of the crown pillar at the Marvel Loch Underground Mine, in Proceedings International Mine Management 2012, pp 125-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

The (SA Mine at Cobar produces a mix of copper and copper lead and zinc ores fran long hole open stopes. Primary jaw crusher product is fed to two parallel primary autogenous mills followed by a secondary ball mill. Each mill operates in closed circuit with cyclones. Grinding equipment and the main operating variables are described. Copper lead and zinc flotation concentrates are produced sequentially. The control systems and operating strategies are described.

Jan 1, 1983

The aim of the study was to determine the ranges of stability and instability of the metal hydroxides and metal cyanide species that may be formed during the gold extraction process, Merrill-Crowe gold precipitation, and Inco S02/Air or ferrous ion cyanide removal processes.Following cyanide detoxification by the Inco S02/Air process, the main components of concern in the tailings will be:

Jan 1, 1997

Tailings management trade-off studies are done for all mining projects. There is wide variability in these studies as their approach, details and outcomes are determined by the experience and focus of the project team. While some of these approaches may consider the whole life cycle of the project others may focus only on capital and operating costs and direct environmental impacts. A complete life cycle approach is not standard practice. This paper describes an approach to implementation of formalised life cycle assessment (LCA) following ISO 14044 to tailings management trade-off studies. The paper describes the implementation of the methodological framework for the LCA, ie goal and scope definition, life cycle inventory analysis, life cycle impact assessment and life cycle interpretation. This standardised approach to implementing tailings management trade-off studies following the LCA approach will contribute to the state-of-the-practice in sustainable mine development.

Jan 1, 2009

IT is most remarkable and valuable property of mediurn and high carbon steels that they should be so susceptible to heat treatment, the wide range of variability in tenacity, ductility, etc, due to the normal influence of the carbon in the untreated material being enormously inereased thereby.The physical properties of steel and other metals are much more closely related to their structure than to their ultimate analysis.For instance, we may by chemical analysis determine the carbon content of a steel to be 0.5% ; but this information alone is insufficient to enable us to say what are the physical properties of the metal.Such a steel may possess 11 tensile strength of anything from 35 tons per sq. in., with much ductility, up to 80 tons per sq. in., with practically no ductility, according to its heat treatment. A microscopie examination, on the other hand, would show the structural composition of the steel, from which its physical properties could be approximately deduced. From this it will readily be understood that the microscope has played an important part in the development of modern rnetallurgy, and to-day it is in daily use for the examination of metals and alloys in the laboratories of most works dealing with the rnanufaeture and working of metals.THE IRON-IRON CARBIDE EQUILIBRIUMTo understand fully the mode of occurrcnce of the different constituents of a knowledge of the Iron-Iron Carbide equilibrium diagram (Fig. I) is essential to heat-treat steel successfully and to interpret microstructures correctly such a knowledge isabsolutely indispensable.A portion of the Iron-Iron Carbide Diagram, dealing with steels below 1000 and containing up to 1 carbon is given below.It should be noted that the diagram deals entirely with pure carbon steels, and does not indicate the influence of the usual so-ealled "impurities" present in all commereial carbon steels...

Jan 1, 1926

By A Buckingham, R M. Hancock

The underground Sunrise Dam gold mine commenced in October 2003 to extract ore from a series of orebodies with various dips, widths, and ore grades over a strike length of 1.5 km. To successfully operate flat stopes it was identified that a means to extract ore left behind after blasting in stopes with dips ranging from 15 to 40 degrees was needed. Various options were available, which included a bulk water cannon, hand held high-pressure water jet, remote controlled small dozer, several mini excavators and finally a specialised remote controlled excavator from the demolition industry. Trials were commenced for the bulk water cannon option in 2006 that proved that the concept worked, however, the system was too cumbersome to set up for use in cycle with production. Hand washing down using mine (low pressure) water with a two-inch bullhose proved of limited value. The small, one metre high remote controlled dozer as used in South Africa was reviewed, but the steepness of most of the stopes precluded this machine. The hand held high-pressure water jet option is still being investigated; with safety factors still being addressed. Several mini excavators were trialled to clean out the flat stopes with generally poor results, the machines being either too large to fit in the drives and pull ore down or too small with too short reach to effectively and efficiently pull ore out of the stope. In early 2007 a Brokk 330 remote controlled excavator was trialled on site with the low profile of the machine and unique arm configuration proving an effective tool for pulling ore from the footwall of short, flat stopes. A Brokk 330 remote controlled excavator was purchased in late 2007 and is currently in operation.

Jan 1, 2008

By A E. McElnea, M A. Martens

An 18-month project was undertaken to test the effectiveness of controlled daily tidal exchange augmented with hydrated lime treatment of surface waters as an approach for remediating a severe acid sulfate soil disturbance at East Trinity, Cairns, north Queensland. Actual acid sulfate soils were producing hazardous levels of acid and heavy metal contaminants and degrading approximately 720 of the 940 ha East Trinity property and the adjacent foreshores. A government-led research team established a series of research projects with the aim of characterising the site (soils, water, terrain) and testing the effect of the lime-assisted tidal exchange management strategy on soils, water, sediments and biota.

Jan 1, 2003

Material sampling theory is well established in mineral process monitoring, improvement and control. It has been much enhanced by fundamental contributions due to Gy. When GyÆs sampling theory is applied to sampling inspection and monitoring, it provides estimates of average quality or extent of contamination. It also provides estimates of uncertainty, but these often ignore uncertainty in estimated variograms or other measures of variability. Risk assessment is often an implied task in sampling inspection and quality monitoring. A valid technique of risk assessment needs to take into account the uncertainty in the variational measures themselves. Standard statistical tolerance limit calculations which do take such uncertainty into account can be adapted to develop a technique for handling uncertainty in variational measures such as the variogram. Data from a published example is used to illustrate the technique.

Jan 1, 2005

By Graham M

Longwall mining has been the dominant global coal mining method for decades. However, not until 1994 did longwall mining surpass continuous miner room and pillar extraction tonnage in the United States. This significant event, occurring in the most cost driven market in the world, confirms the efficiency and effectiveness of longwall mining.

Jan 1, 1998

By J Herbertson

æZero waste steel making productionÆ has already been the subject of several studies and also the successful result of some companies. Regarding waste and by-products, slags are the largest in terms of weight, although among the least hazardous. All steelmakers around the world are presently looking into profitable solutions, according to their local conditions: environment constraints, available markets, and mode of operation. Today the major technical methods of slag value capture include different levels of magnetic separation and screening to remove entrained steel, for production of aggregate in civil works. A survey of different retrieval processes shows that pyrometallurgical processing of steelmaking slags will increase the recovery ratio of iron and other metals. In the process, the remaining part of the material, a mixture of metallic oxides, can be easily transformed into hydraulic binder such as cement. Can steelmakers consider the slag as a co-product, and not only a waste or by-product? The ability of pyrometallurgical processes to treat other wastes and by-products generated in the steelplant is an opportunity for the steelmakers to reach the æzero waste productionÆ status. A technical survey of the experiences and possible solutions of pyrometallurgical processing is presented as well as technical descriptions of technological, economical and profitability analysis in relation with foreseeable markets.

Jan 1, 2002

By J Nemcik, E Baafi, I Porter, G Spinks

Spray-on liners used in the mining industry for ground support and stabilisation applications are either cement based (æshotcreteÆ) or polymer based (æthin spray-on linersÆ). Some thin spray-on liners are a blend of both polymer and cement (eg Tekflex). A small number of thin spray-on liners (TSLs) have been trialled in Australia as potential replacements for steel mesh in roadways and other underground mining applications; however, they were found to cure slowly and the cured coatings became brittle after an extended time in place. The University of Wollongong in collaboration with the Australian coal mining industry has shown that a viable polymer-based alternative to steel mesh in underground roadway support applications can be developed to eliminate the use and handling of steel mesh. The work to date has: established the feasibility of developing polymeric alternatives to steel mesh in underground roadway support applications; identified the physical and material constraints to be endured by any new polymeric skin reinforcement system by measuring the mechanical properties of steel mesh; identified materials that can be spray applied; and demonstrated that polymer mechanical properties can be optimised to produce similar mechanical properties (elastic modulus, yield stress, elongation-at-break, etc) to steel mesh. The identified materials will: allow the face support cycle to be fully automated, or at least remotely operated and installed; remove personnel from the immediate face area; and substantially improve underground roadway development rates.

Jan 1, 2008