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By I Coombes, M Trim, Y Sun, M McRae, A Spiegl, H Lagger, A Amon, P Barraclough, M Villeneuve

The Brisbane Airport Link Project (AirportlinkM7) includes the design and construction of more than 12.5 km of tunnels, with the Kedron interchange including four ramp tunnels that intersect with mainline tunnels and result in caverns with spans of up to 26 m. These caverns are in highly variable ground conditions with less than 35 m of cover underlying residential neighbourhoods and commercial properties. The Kedron caverns were constructed using the sequential excavation method (SEM). Owing to complex geometry and excavation sequence, the caverns were designed based on numerical modelling methods, including both two- and three-dimensional models. These numerical methods were used to develop a suite of support types with excavation sequences for the expected range of ground conditions. A combination of methods that included in-tunnel monitoring (convergence monitoring and extensometers), probe holes, endoscope probes, face mapping and ground settlement measurements were used to verify performance of the tunnel support systems and to select and refine the appropriate support system for each section of the caverns. The construction monitoring data indicated that numerical modelling can provide a good basis for predicting the performance of large-span underground openings in highly variable ground conditions. This paper presents a comparison of the performance of the caverns predicted by state-of-the-art numerical models and the actual measured performance.CITATION:McRae, M, Villeneuve, M, Trim, M, Sun, Y, Barraclough, P, Spiegl, A, Amon, A, Lagger, H and Coombes, I, 2014. Brisbane Airport Link Project – design and construction of the 26 m span Kedron Caverns: comparing monitoring data with the design, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 295–306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By K B. Quast

Changes in feed size distribution can have significant effects in rod mill grinding. The product sizing resulting from wet batch milling of a tin ore showed little influence on fines production after truncating the feed at either the coarse or fine end. The addition of fine material caused a less amount of fines to be produced and a possible increase in grinding at coarse sizes, although this is complicated by the changing feed size distribution. The changes in feed size distribution caused no tendency for preferential grinding of the cassiterite.

Jan 1, 1998

The energy supply in the 21st century is still secured by coal. According to estimates of the International Energy Agency (IEA), coal will have the same importance as oil for the world-wide supply of energy until 2030. Coal is also an important element of EU policy, its future use is closely linked to effectively addressing the environmental challenges it poses. Hard and brown coal represent approximately 80 per cent of European Union (EU) reserves of fossil fuels and coal utilisation can co-exist with the development of power generation based on renewables. Europe is the world's third largest consumer of coal behind China and the United States.The Czech Republic is poor in energy resources except for coal. Brown coal is relatively abundant (mineable reserves estimated at 1800 Mt, output 48 Mt/a) and significant quantities of hard coal (mineable reserves 900 Mt, 13 Mt/a), much of it suitable for coke production, are also present.Severoceske Doly (SD Company), the biggest Czech coal mining company (22 Mt/a, 48.6 per cent Czech market share) and one of the biggest in Europe, reinforces despite the last deep crisis in the Czech and European economies its long-standing stable and strong market and financial position. From 2009, the SD Company co-owns, with partners, a brown-coal mining company MIBRAG (21 Mt/a). SD Company invests in large mining equipment (eg new giant spreaders and bucket-wheel excavators, extension of overland belt conveyors), rebuilds and upgrades mining and processing installations, auxiliary and other machinery. We should see the investment we make today in tomorrow's mining and reclamation as an opportunity and not as a burden. They enable to make our position more resistant in the longer term. Projects focused on the environment and operational safety went hand in hand with these efforts.R&D activities relate to technical innovations, improvements of mining equipment, research and evaluation of conditions for extracting coal seam and/or overburden and mitigation of environmental impacts, utilisation of coal in new products. The company spends considerable amounts on reclaiming affected land and creating a new post-mining landscape.Our dialogue with influential stakeholders in the region where we operate contributes to the long-term improvement in the quality of life of local residents. Such dialogue with communities in the last ten years has been instrumental for confidence building. SD Company helps to develop many projects of towns and villages in its vicinity. The stable and transparent relations with our neighbours are in accordance with our basic principles of corporate social responsibility.

Dec 6, 2010

By Johnson M. W

Factual data about the sedimentation in the Newcastle Coal. Measures are presented. Data concerning the total coal measure sequence (isopachs, sand /shale ratio and total coal thickness variation), data about three coal seams (Borehole, Dudley and Victoria Tunnel) and data about interseam con- glomerate units are discussed. From this data conclusions are drawn about the coal measure environment. The western edge of the coal basin, the Lochinvar Dome, although a high feature was apparently stable during coal measure time. Despite its height it apparently supplied little sediment to the basin. The northern and north-eastern edge, which was unstable, suppl- ied most of the coarse detritus including the conglomerates to the basin. The conglomerates show patterns of fluvial origin but after a period of "normal" variations in pattern they become restricted to two parallel zones evidently tectonically controlled. Deposition of conglomerates is episodic and separated by periods of coal formation when deformation was apparently slight. Formation of each of the three seams considered followed a rather similar pattern - each shows development of thick coal around the basin edge and poor thin coal in the "axial" region of the present synclinal structure. Evidence of in-situ formation of some areas of the seams is discussed and periodic deformation of the basin during coal measure time is postulated.

Jan 1, 1969

For years traditional optical microscopic techniques have been used successfully to carry out mineralogical studies on processing products. Essential information could be obtained by supplementing microscopic data with X-ray powder diffraction data, chemical analyses, etc. However, most of the time the mineralogists working on plant related issues, would supply qualitative information to the metallurgists, due to quantification not being possible in the available time. Since the late-80s, the use of semi-automated to automated techniques for mineral quantification has impacted positively on the use of mineralogy for optimising processing plants. Rustenburg Platinum Mines (now Anglo Platinum) were the first mining company to purchase a Qem*Sem in 1987. With the success achieved in quantifying the minerals in the concentrator streams of the Rustenburg Platinum operations, a second instrument was purchased soon after. These instruments have proven invaluable tools in understanding the flotation behaviour of the sulfide and gangue minerals in the various reefs of the Bushveld. Restrictions in the resolution of these earlier instruments, as well as the time involved in searching for and correctly identifying the fine-grained platinum-group minerals (PGM), meant that these investigations focused on the deportment of the more abundant base metal sulfides, rather than on the actual PGM. The Mineral Liberation Analyser (MLA), which became available in the late 1990s, was well suited to detect and analyse minerals occurring in trace amounts such as the PGM. Anglo Platinum was the first mining company to purchase such an instrument and now has fourteen systems operating at the AR Crown Mines site. One of the applications of these systems involves the study of feeds, concentrates and tailings from the various concentrators on a monthly basis. These routine investigations provide information on a variety of mineralogical parameters, including liberation, association, and grain size. Results are used to emphasise areas for improvement, and specifically underline those areas where improvements will have the most impact on recovery. After new or different technologies have been implemented, mineralogical characterisation of the different process streams is an essential component in the assessment of the impact of these changes on flotation performance. In addition, the knowledge is databased for future reference to draw trends across the various concentrators around the Bushveld complex, and is also used for comparative studies when plants experience high losses to tailings. Due to the success of these investigations the question was posed whether it was possible to obtain data on a daily basis, as compositing samples could hide the impact of daily events. Although the instruments currently used are suitable for a research environment, these are not ideal for mine-site implementation. For that reason Anglo Platinum, together with FEI embarked on a development program to develop a system that can be implemented on-site to measure the important mineralogical characteristics on a daily basis. Important requirements for such a system include time-to-data, ease of use and regular quality control. Highlighting some results from concentrator studies, the presentation will review the progress on the development of automated mineralogical techniques for fast, automated mineral measurements. This is an abstract only. No full paper was prepared for this abstract.

Sep 13, 2010

By J Morton

The Resource Management Act 1991 represented an innovative and unique piece of planning and environmental legislation when it was introduced. Since the Act was passed into law in 1991 it has been subject to nine amendments, many of which were of the ætinkerÆ variety. These amendments recognise that the Act has not been as successful in providing the æone-stop shopÆ for resource users that the Act was hoped to be. The latest and most significant attempt at changing the Act was the Resource Management Amendment Act 2003. The amendments made by the Amendment Act have proved to be largely unsuccessful in achieving any significant changes to the way resources are managed in New Zealand, and have failed to address many of the concerns which drove the original Resource Management Amendment Bill in 1999. The recent decision to discontinue further investment in Project Aqua has once again placed the Act in the spotlight as a significant hand-brake on major projects. This particular event has led to yet another review to be undertaken this year. The review will focus on five key areas:   1.   achieving the right balance of national and local interests; 2.   improving the design and process for local policy formulation; 3.   improving the consent decision making process; 4.   allocation of natural resources (water, air and geothermal); and 5.   supporting measures for building capacity and promoting best practice and implementation at the local authority level.  It is important for the business community and the mining industry in particular to seize the opportunity that this review provides to make sure that any amendments undertaken as a result of the review achieve the aims listed above. The review needs to be considered in light of the current regime for the management of natural resources in New Zealand. In addition to the Resource Management Act 1991, the Crown Minerals Act 1991 and the Building Act 1991, which form the core resource statutes in New Zealand, there have been other developments affecting the regime. Special legislation over and above the Resource Management Act 1991 has been enacted to protect the Hauraki Gulf and special legislation is currently being considered to protect the Waitakere Ranges in Auckland. In the Hauraki District mining is prohibited in some areas and a plan change mechanism is specified as the appropriate tool to use in the event a mineral resource is to be developed in those areas. The current review is a further opportunity to remedy the inadequacies of the Act.

Jan 1, 2004

Both here and in Australia, the unique commercial and tax features of joint venture are finding favour in forestry, fishing, technology and infrastructure projects. For New Zealand mining companies, joint ventures provide a means of access to foreign know how and investment funds, while retaining their corporate independence and their hard-earned tax losses.   This paper discusses some of the practical income tax and GST considerations where a joint venture structure is contemplated. The first part of the paper considers income tax, and in particular how joint ventures enable companies to access and carry forward tax losses. It explains why a joint venture may be advantageous relative to a jointly owned company.   The second part of the paper concerns GST and the focus is on two aspects: 1.   Joint ventures may be registered for GST. In some instances they have no choice and are required to do so. Where a joint venture is registered in respect of a taxable activity, the members are not permitted to register in respect of the same activity. This may be problem where the member has incurred its own expenses and the member wishes to register in its own right to claim back the GST on those expenses. This paper explores the issue and possible solutions. 2.   It is not uncommon to see joint ventures claiming GST on the costs of production, and the production being sold (and GST is being charged) by the members. In this paper we consider whether these arrangements have a tax risk, and what can be done to make them technically sound.

Jan 1, 2005

By E Christodoulou, L Zoumpoulakis

The kinetics of the thermal decomposition of MgCO3 was investigated using isothermal experiments performed in a thermogravimetric analyzer under a nitrogen atmosphere at 380¦, 400¦, 450¦ and 480¦C. The weight loss data as a function of time were modified to give the fraction that reacted (ß) and the rate of reaction (dß/dt) vs. time (t). Kinetic analysis of the experimental results, using three different methods, showed that diffusion predominates the MgCO3 decomposition over the investigated temperature range, with the data being best fitted by JanderÆs equation ([1−(1−ß)1/3]2=kt). The activation energy was estimated by Arrhenius plots using both the initial reaction rates and rate constants from fitting the above equation. The values estimated were 27.1 and 171.4 kJ/mol respectively.

Jan 1, 2001

By I P. Hodkinson

SMC Resources Limited is implementing a selective mining approach at the Hadleigh Castle mine, formerly operated by Aurora Gold Limited. The main ore zone has a length of 250 metres and dips at 40 - 45¦ to the south. Gold mineralisation occurs in a variety of quartz-sulphide lodes in sericitised granodiorite. Shallow dips, alteration intensity and mineralisation style combine to make mining relatively difficult. Previously unworked, high-grade, shallow dipping (30 - 45¦), narrow quartz-sulphide lodes within the hanging-wall of the deposit are also being selectively exploited. Annual production of 35 000 oz Au is forecast from 185 000 tpa ore grading 6.5 g/t Au over a currently envisaged mine life of six years. Operations completed to-date include deepening the decline and access development of the first two levels beneath the previous workings. Longhole stoping operations have commenced in the main ore zone with air leg stoping also underway in the hanging wall lodes.

Jan 1, 1998

One of the major changes in the resource industry in the nineties has been the re- internationalisation of the industry. The history of the resource business has been one of companies from the developed world utilising the cash flows from their operations to explore and develop mines in less developed regions of the world. This resource development has progressively generated wealth and economic development, which in tum, has led to a new generation of exploration and mining projects.   InSouth America, Chile had led the way in a mining resurgence, now closely followed by Argentina, Brazil, Venezuela and Peru. Although Chile has long had a significant copper mining industry, the pre-nationalisation phase was driven by American capital; the current phase has been spearheaded by RTZ - BHP at Escondida with Canadian junior companies, in particular, providing major speculative impetus. The Australian junior companies have not been significant in South America.   Although Canadian and USA exploration appears to be in decline, the mining industry, particularly in gold, is buoyant in North America. Interestingly, a number of listed and unlisted Australian companies are active, particularly in United States exploration.   Australian-based companies have dominated the South-East Asian exploration scene, especially in the Vietnam region. To date, the combination of political and legislative uncertainties have failed to lead to significant resource developments in this region. The area remains one of great potential, as exemplified by the exciting developments in Indonesia.   The Philippines has a history of mining, and this has been dominated by both local and North American operators. Both large and small Australian resource companies have a presence in the Philippines, and the development of the copper-gold potential could be impressive over the next decade.   The tales of the undeveloped mineral potential of China are probably rivalled only by the supposed strings of virgin Russian orebodies! Many Australian companies appear to have looked but few have chosen to proceed with Chinese developments. There seems little likelihood that China will, in the foreseeable future, rival South America as a target for Australian and North American resource capital.   Papua New Guinea has had an active, albeit chequered history in mining, with Australia long being the predominant source of exploration and development funds. The developing nation status of PNG has generated extreme uncertainty, with the current exploration scene all but dead. Most recently, the international flotation of Lihir Gold has tested the international and Australian investment community's commitment to PNG resource development.   The Australian exploration scene continues buoyant, although dominated by gold. The base metals scene is generating, on average, one significant base metal mine developed every couple of years. This is probably the fastest rate of significant base metal development in Australia's history.   The gold scene has been one of incredible dynamics, and there is no evidence that this momentum is waning. The development of new exploration techniques, together with a number of the companies reaching a critical size, has added to the momentum in the industry.

Jan 1, 1995

Most people are familiar with Euclidean dimensions: zero for a point; one for a line; two for a plane; and three for a volume. Howeverbobjects are not actually Euclidean, but lie somewhere between Euclidean æend-membersÆ with a non-integer fractal (or æfractionalÆ) dimension. The fractal dimension D is a measure of the relative importance of large versus small. Consider the trace of a coastline on a map. It has a fractal dimension (1 =D =2) somewhere between a line (dimension = 1) and a plane (dimension = 2). The more tortuous the coastline, the higher the fractal dimension, and the closer it becomes towards a plane. The concepts of fractals and spatial geometry can be applied to a wide range of geologicaVmining problems as well as than those dealing with space. One commonly quoted fractal relation is the log-log relationship of ore-grade and tonnage. Until recently, we have never been able to define or measure spatial-geometry, but new developments in mathematics have provided a means by which to quantity and apply it to our problems.

Jan 1, 1992

Flotation testing has been done at laboratory scale on hematite mineral and ore samples using stage additions of various hydroxamates. Chemisorption of hydroxamate species onto the hematite surface was inferred from the results, possibly involving both the undissociated hydroxamic acid and hydroxamate ion as maximum recovery occurred close to the pKa of the hydroxamic acid. Flotation testing on a specular hematite ore containing 40 per cent Fe and 42.5 per cent silica gave highest iron grades in concentrate at pH 6, in contrast to published data which suggested pH 9 as the optimum value for ore processing. Using octyl hydroxamate, a rougher concentrate assaying 67 per cent Fe at 51 per cent recovery was obtained using four stage additions of 50 g/t at pH 6. For lower grade concentrates still meeting the chemical analysis for pigment grade micaceous hematite (minimum Fe assay 60 per cent) iron recoveries of 80 per cent were possible for stage additions of 50 g/t octyl hydroxamate in the pH range 6-8.

Jan 1, 1999

Project Sustainability Assessment - Matching Method to Enterprise Size Sustainable development requires managing natural resources, including minerals, in a way that is conducive to long-term wealth creation and the maintenance of capital (natural, social, human, economic and physical). One aspect of the minerals sustainability discussion focuses on replacing depleted mineral capital with other forms of capital so as to ensure that the contribution of a mineral project is net positive over its life. Another, equally important, aspect focuses on selection of projects and technologies that contribute to the achievement of a variety of sustainability objectives, such as environmental protection, efficient use of resources, water and energy, worker health and safety, and the equitable distribution of risks and benefits within and across generations. Technical feasibility and relative economic performance remain necessary decision criteria for mineral investment decisions, but they are no longer sufficient. Enterprises, regardless of size, are now confronted with the challenge of comparing investment alternatives based on a new, broader set of criteria. The field of integrated sustainability assessment (ISA) emerged in response to this changed social and business environment. ISA is a structured process for examining the economic, social and environmental impacts of a project or technology. The purpose of an assessment can be broad, a strategic review of corporate behavior for example, or quite narrow, input to a specific decision process such as the selection of a piece of equipment. There are numerous methods and analytical tools available to conduct ISAs and selection of the most appropriate for a given situation will depend upon temporal focus (retrospective to prospective), decision context (strategic, tactical or operational), and phase of the assessment process (problem structuring, analysis, resolution, ex post review), among others. Selection also depends upon enterprise size and the attendant availability of financial and human resources. Large multi-national firms often undertake complex, data intensive sustainability assessments, in part because the projects they are involved in are multi-faceted, long term, and require significant financial investments. Small and medium sized enterprises are seldom able to commit the same level of resources to an ISA, and if the projects they undertake are less complicated, a time consuming and detailed assessment may be unnecessary. Regardless of enterprise size, the tangible and reputational benefits of conducting as ISA must exceed the actual monetary cost of doing so. This presentation will provide an overview of available ISA tools, categorising them in terms of their data requirements, methodology, outputs and applicability in various decisions contexts. Distinction will be drawn between situations where reasonable approximations of project impacts can be expected to provide an adequate amount of information and those for which more detailed analysis is essential. Finally, ISA strategies that have been successful and cost effective at different scales of business enterprise will be identified. This is an abstract only. No full paper was prepared for this presentation.

Sep 13, 2010

By A Clark

When production targets are not being reached it is essential to determine what the operating problems are so that remedial action can be taken. It is also imperative that all persons who are part of the production stream within a mining operation know and understand what the operating difficulties and delays are so that corrective action is effective. This includes the supervisors, superintendents, planning team members and managers. A new approach recently adopted at Hilton Mine to help identify these operating difficulties has been to use short-term schedules and reports known as the Daily Shift Schedule Controls (DSSC), and the Daily Weekly Operating Reports (DWOR) respectively. These control elements have enabled management and supervisory staff to accurately identify labour inefficiencies and ultimately determine capital resources.

Jan 1, 1998

By T O&apos, Beirne

The paper focuses on explosibility conditions in underground coal mines, the behaviour of explosions from initiating gas ignitions to violent dust explosions and the effectiveness and limits of operation of current designs of passive explosion barriers in suppressing the flame front. Areas of particular emphasis include: passive explosion barriers are not designed to protect personnel in the flame initiation zone and its immediate surroundings; passive dust and water barriers are generally considered ineffective against methane ignitions of the magnitude that can occur at the working face; dispersal of suppressant from passive barriers is adversely influenced by equipment, including conveyor belts, located in the barrier zone; current regulations in Australia do not specify the installation of barriers in all roadways leading to the face, so their use has a limited capacity to contain explosions; a manifest design limitation is that passive barriers are restricted to one operation and are therefore ineffective against repetitive fire gases explosions; and the practice of stone dusting in roadways inbye the barrier zone could conceivably adversely affect the operation of passive barriers. The paper discusses performance evaluations made in full scaleexplosion galleries and the use of alternatives to passive barriers,including the installation of active barriers under some circumstances.

Jan 1, 1997

Landscape interpretation, geology and mining history is being successfully used to explore options for sustainable community tourism product development. Recent work by the author in Europe and Australia has indicated the value of adding and producing interpretive information about mine and quarry locations - both active and inactive. This work has allowed for the branding and development of new sustainable community tourism products based on the landscape, folklore, mine and geological heritage.   Communities in rural areas are seeking new opportunities to sustain their local economies. Using a relatively new phenomenon called geotourism as a starting point; they have developed themed products connected to walking/cycling guides, interpretive panels and visitor centres. These themes can be linked to geology, archaeology, botany, local history and to industrial heritage sites such as old mines, to generate local employment. This new geotourism approach has successfully brought a new and greater audience to discover the value of geology and mining history.   Communities have established a unique place for themselves within the tourism marketplace using the geotourism brand. Other communities with an established tourism product are also now using geological and mine heritage via geotourism to rebrand and meet changing global trends. The pooling of resources under the banner of geotourism has led to cost effective marketing, targeting and promotion of products.   Geotourism has emerged strongly in Europe, North America and China in the last decade. The Australian minerals industry now has an opportunity to implement this new branding concept to assist and benefit the communities in which they run their activities. Communities can also take advantage of the potential to develop a sustainable geotourism business around a past or present mineral industry in their vicinity.

Jun 1, 2010

Experimentally determined and theoretically explained phenomenon of zonal disintegration of rock around the development working brings about the radical changes in existing ideas about the mechanism of interaction rock massive with engineering constructions.The essence of the phenomenon consists in the fact, that forming of non-elastic deformations zone goes on by way of more intensive deformation and destruction of rock simultaneously in several zones, covering partially or fully output circuit and divided by zones of destructed rock. Under the influence of change of massive strained-deformational condition of depositional rock an accidental deviation of zones of supplementary expansion and compression of rock from the previous positions take place. One can observe multiplicational change of the outline, size and form of all disintegration zones in the time within the area of the working influence at massive. This phenomenon was named "fluctuation of zonal disintegration of sedimentary rock around development working".

Jan 1, 1991

Large mining operations need equipment that consistently performs as expected. The most effective way of ensuring this is to have a defined life cycle with an optimised maintenance strategy. The determination of this life cycle is an economic decision, influenced by the construction and utilisation of the equipment. An effective life cycle costing (LCC) tool must be able to process the many variable factors involved.Many factors influence the costs that are associated with a machine over its life. The most variable of these are the costs of maintaining the equipment. Maintenance costs are dependant not only on the utilisation of the machine, but also on the strategy that has been developed to support the machine through its life. A combination of supplier support, component changes, regular servicing and unscheduled maintenance needs to be modelled, based on a variety of drivers. Traditionally spreadsheets have been used to model these factors, but the increasing complexity of the situation can make spreadsheets unwieldy and difficult to manage. A database solution that breaks each activity into its constituent components, links them to an associated mine plan driver and then aggregates the result is the ideal tool to provide a time based cost profile. The evaluation of a number of scenarios, representing different maintenance strategies/life cycles can be rapidly undertaken. Auditability through inbuilt tools is required to provide easy tracing of data. Use of the host company's account structure allows for reporting against the standard chart of accounts.

Dec 6, 2010

Mineral Processing Education in China

Sep 13, 2010

The traditional measure of Lost Time Injury Frequency Rate (LTIFR) as a measure of improvement in safety performance is recognised as inadequate and misleading, lulling managers into believing that safety is improving. It is a reactive measure, and steadily declining LTIFRs around the world have failed to be accompanied by a similar reduction in the fatality rate. This paper confronts the industry with the attitudes of some mining managers, such as one that allowed fatalities to occur in the case of a gold mining company at a rate of one death per 150 000 ounces of gold produced while claiming their safety record has improved, as shown by a falling LTIFR, and viewing fatality reductions as a long-term goal instead of an immediate priority. A quantum shift in management attitudes is required to focus on proactive measurements to detect the indicators of an impending disaster, and to predict conditions conducive to fatalities. Corporate CEOs are challenged to attend the funerals of all workers killed in the workplace. CEOs who fail to attend such funerals send a message to employees that the CEOÆs priorities lie elsewhere, and that profits take priority over workersÆ lives. The dichotomy of whether mining companies are run for the benefit of shareholders or whether companies owe social responsibility to the community is examined. The role of individual responsibility for personal safety is examined, together with the psychology of employees in the mining industry. A number of proactive measurable indicators are suggested to stimulate discussion on developing robust measuring tools to predict and therefore prevent fatalities.

Jan 1, 2003