Search Documents

RME has a vision for a new mill operational paradigm made possible by RMEÆs fast, safe Mill Relining System. This vision can be moved forward into reality at any time with or without guidance from recent development in measurement and predictive modelling tools.Some new liner designs can degrade SAG mill performance because of mill volume loss, ball strike (rotational speed limitations) and other issues often brought about by optimising liners for life and without a backward glance at metallurgical consequences. Freshly relined mills can initially produce as little as 80 per cent of their maximum throughput, that maximum occurring toward the end of the linersÆ wear life. RMEÆs proposition is to design new liners for maximum commercial performance. This may mean more frequent changes of liners but with liners designed to yield optimum grinding, metallurgical and profitability performance. In other words, mill liner profiles and mill relining speed become key operational controls and not simply æmust doÆ maintenance functions. Taken to the extreme, liner profiles may prove capable of ætuningÆ a grinding plant for maximum profitability in any metal price environment. This paper provides an update regarding RMEÆs fast, safe Mill Relining System technologies and outlines RMEÆs vision of a æliner profile versus profitabilityÆ model as a function of metal price, developed intuitively or by using a combination of new measurement and modelling technologies. These new measurement and modelling tools provide the opportunity to predict the optimum commercial outcome, off-line in the virtual world, before committing to an expensive liner experiment.

Jan 1, 2006

By S Hille, J Karageorgos

With the increased variability of todayÆs large-scale mining operations, consistent flotation performance is important to improving and sustaining overall recovery through the circuit. The Newcrest Telfer Mine has implemented advanced process control technology to obtain stable level operation and consistent mass pull in the copper rougher and scavenger flotation circuits. The final result has been an overall reduction in variability, which impacts on both copper and gold recovery. This paper describes the methodology and implementation of the improvements in control at the Newcrest Telfer Mine as being an essential part of the business for minerals processing.

Jan 1, 2007

By R Jacobs

"The Jaguar project is relatively unique in that it was evaluated, financed, built and operated to completion within the last ten years, providing the opportunity to holistically review and reconcile expectations against the actual outcomes. It is a case study that allows wider conclusions to be drawn with respect to the risks and opportunities involved with project evaluation and execution.Jaguar is located in the Leonora Mining District of Western Australia and was commissioned in mid-2007 as an underground accessed, single high-grade volcanic-hosted massive sulfide (VHMS) deposit with an on-site concentrator, producing copper and zinc concentrates exported via the Port of Geraldton to South-East Asian markets.The feasibility study (FS) had several iterations (JML, 2005a); the last dated July 2005 was specifically targeted to secure project funding, and summarised the reserves-only portion of the resource and its planned exploitation. The commissioning of the mine was the transition for the owner Jabiru Metals NL from junior explorer to producer and the project was the dominant asset of the company.Jaguar operated through several significant deviations from the linear project plan set out in the FS, including the Global Financial Crisis (GFC), a corporate takeover and disruption to the mine plan from the onset of material geotechnical issues. Whilst the GFC or mining disruption were not specifically predicted in the FS or peer reviews, the generic effects of the events were assessed in the project risk assessment and they influenced subsequent management decisions. In parallel to the internal project-specific risks, the short planned life of Jaguar was a risk to the continuation of the corporate entity which was being addressed by significant investment into brownfields exploration to extend or replicate the project, and ultimately added value such that attracted a corporate takeover.Holistically, the project delivered the returns predicted in the FS, but in a much different guise than was expected. This paper will describe the reality of operations compared with the study predictions and expectations through the perspective of the project and corporate risk assessment.CITATION:Jacobs, R, 2016. Jaguar base metals project case study – has reality reflected the study?, in Proceedings Project Evaluation 2016, pp 86–97 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By D Connelly

Magnetite orebodies generally means mining lower grade iron ores, crushing and grinding with significant energy costs in processing and the capital costs being significantly higher than for direct shipping ores (DSO). Overseas, the mining and processing of magnetite ores has a long history of production due to the lack of DSO deposits. This raises the question as to why the new magnetite projects have been so problematic and also whether there is a future for the long list of potential magnetite projects in Australia.The quality of the magnetite concentrate product is superior to most DSO products and the magnetite contains energy benefits when converted to hematite in sintering or pelletising. The industry’s hopes for new projects have been dashed and questions are being raised as to the financial viability of such projects.A comparison of Grange Resources Savage River, Arrium’s Project Magnet, the Sino Iron Project and Gindalbie’s Karara Iron Project is used to understand the differences between the projects and why some are more successful than others.CITATION:Connelly, D, 2015. What is the future for magnetite projects in Australia and why have some of the new projects been so problematic?, in Proceedings Iron Ore 2015, pp 107–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By R Valenta, J Owen, D Kemp, E Lebre, G Corder, J Thomas

Numerous recent analyses have shown that future demand for a broad range of critical commodities is unlikely to be met by new discoveries and recycling alone. The only practical alternative source to address this shortfall comes from orebodies which are currently either uneconomic or inaccessible. A common assumption is that a simple rise in commodity price will render these deposits economic. The mining industry has a long history of innovation allowing economic production from increasingly low grade and technically challenging orebodies. Industry “roadmaps” have been produced on a regular basis, with the aim of identifying future innovations which will allow this progression to continue. At the same time, there have been relatively few systematic analyses of the actual range of challenges facing undeveloped orebodies. The aim of this study is to analyse the mix of challenges faced by a group of undeveloped orebodies in order to better understand the relative importance and necessity of innovations applicable to the deposits, with the ultimate aim of determining the relative value and impact of possible innovations to the economic viability of those deposits. CITATION: Valenta, R, Lebre, E, Kemp, D, Owen, J, Corder, G and Thomas, J, 2018. Can a simple price-rise unlock complex copper orebodies?, in Proceedings Complex Orebodies Conference 2018, pp 71–72 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By Singh T, Singh D. P

India has limited resources of coking coal. Most of the coking coal seams are located in Jharia Coalfield. These seams were worked in the past by the bord and pillar system in a haphazard manner, which has resulted in honeycombs of old working. Most of such areas are under fire. In order to meet the demand of coking coal in the 21st century, it is essential that the coal locked due to old underground workings is recovered fully by conducting opencast mining to an ultimate depth of 500 m. The major problem envisaged in conducting opencast mining in such areas will be the stability of pit slopes over voids and the behaviour of subsided material in the pit slopes. An attempt has been made to simulate this complex situation from a specific section of the rockmass of a mine in an equivalent material (EM) model. The old workings existing in upper coal seam (V) were simulated by developing staggered bord and pillar workings in two sections and depillaring them. Opencast mining was conducted for recovery of coal locked due to irregular working in coal seam V. The slope instability caused by intersection of the slope with the void, during frontal working (by shovel-dumper combination) was observed in various situations. In this paper, the technique adopted for simulation of a 125 m thick section of rockmass in an EM model is outlined. Adverse effects of staggered workings and

Jan 1, 1988

By E P. O’Dwyer

Segment and gasket lining in tunnel boring machine (TBM) tunnels; and sheet membrane lining systems in driven tunnels are robust waterproofing systems each with a proven history of performance in Australia and further afield. Where an interface between these two systems occurs, the potential for costly failures is vastly increased and additional attention to detail is required in design, planning and construction. TBM cross-passages represent the most common occurrence of this interface, with steel compression flanges and neoprene gaskets being the typical means of connecting the waterproofing systems. There is a large variance in both detailing these flanges and associated outcomes, which makes this an area where there is room for improvement within the industry.The paper will look to tease out the various issues associated with this interface and how they can be dealt with efficiently with appropriate design measures, robust planning and carefully controlled construction methods.The paper will also look to review the new technologies and systems currently being put forward as potential alternatives, including an epoxy tape system, which has recently been successfully trialled on a project in Europe under high-pressure head.CITATION:O’Dwyer, E P, 2014. The challenge of waterproofing cross passages in segmentally lined tunnel boring machine tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 315–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Abdalla MH

The deformation resulting from the presence of a tunnel may signifcantly affected, nearby structures and need to be considered during design of both tunnel and structure. The aim of this paper is to study the effect of different factors which may affect the interaction between the tunnel and the str- ucture. These include; the depth of both tunnel and foundation level of the structure ( z and t ), distance between C.L. of tunnel and loads, breadth of the loaded area, Diameter of tunnel and lining of the tunnel. The problem is studied as a two dimensional plane strain model by the boundary element technique. The results of this study indicated that the presence of a cavity/tunnel increases, in general, the vertical displacement on the ground surface and at the foundation level as well as the horizontal and vertical stresses in the cavity/tunnel level. The effect of eccentricity is increasing as e/D decreasing. For pile foundation there is a quite different- influence of the presence of cavity/tunnel in both cases of friction pile and end bearing pile type of foundation.

Jan 1, 1987

By T G. Vizcarra, B Wong

Optimisation projects are regularly undertaken without knowing the root cause of an issue. It is all well and good to trial a multitude of flotation reagents, change the operating characteristics of your flotation cells, or add more media into your ball mills, but time and again, root cause analysis traces issues back to the performance of hydrocyclones. In JKTech's experience, hydrocyclones are poorly operated and maintained (in both primary grinding and regrind circuits), exacerbating issues that many operations commonly experience.Recent case studies are presented where JKTech has been engaged to improve the process only to discover that the hydrocyclones were the main issue. At one operation it was found that the hydrocyclone feed density gauge was reading significantly lower to the actual density. Following re-calibration of the gauge, and with further improvement of cyclone operational and design parameters using JKSimMet, a significantly sharper efficiency curve was achieved. This resulted in improvements to downstream recoveries while alleviating pumping capacities that were previously constrained by fines and water caught up in recirculating loads.Several other case studies are presented which may seem to be relatively basic, but many basics seem to be getting lost in the day-to-day responsibilities of the modern plant metallurgist. Simple fixes to hydrocyclones can result in significant production increases, but more focus is needed in monitoring these to sustain the benefits.CITATION:Wong, B and Vizcarra, T G, 2018. What category cyclone is devastating your plant?, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 665–673 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By K Sanematsu

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Ore deposits of rare earth elements (REE) in South-East Asia are classified into four types: carbonatite, allanite, ion-adsorption and placer. Occurrences of the carbonatite deposits are confined almost exclusively to the Red River Fault Zone of northern Vietnam. Since the carbonatites contain dominantly REE fluorocarbonates (eg bastnasite) and lesser amounts of monazite, they are rich in light REE but poor in heavy REE. The ion-adsorption type deposits and prospects were found in Myanmar, Vietnam and Thailand. The ion-adsorption ores generally show lower REE grades than those of the carbonatite type and placer deposits; however, they could be enriched in HREE, which are more precious and scarce commodities than LREE. The ores consist of weathered granites with a significant amount of ion-exchangeable REE, which are extracted by using a dilute electrolyte solution. The ion-exchangeable REE are likely to be sourced from REE fluorocarbonates, allanite and titanite because these minerals are relatively susceptible to weathering and release REE3+ ions into soil water. In contrast, monazite and xenotime are resistant to chemical weathering and could form placer ores. Placer monazite and xenotime have been processed as by-products of placer Sn, Zr or Ti in Malaysia, Thailand and Indonesia, although the current production is small.CITATION:Sanematsu, K, 2015. Rare earth element deposits and prospective areas in South-East Asia, in Proceedings PACRIM 2015 Congress, pp 671–678 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A Sinuhaji, H Kalangi, T B. Setyoko

Ore fragmentation at the DOZ block cave mine is highly variable, both as a function of rock type and column height of draw. Initially, the mine was constructed and equipped with limited capability to handle drawpoint oversize material. Significant issues with drawpoint availability and achieving overall mine production targets resulted. A suite of secondary sizing tools was added to the mine equipment fleet over a one-year time frame. Although significant oversize continues to be experienced, use of the correct secondary breakage tool for each particular oversize or hang-up occurrence has resulted in increased drawpoint availability, production rate, draw compliance, and operator safety. Currently, a range of secondary breakage techniques is being utilised to size material for delivery to the primary crusher. Run-of-mine material (3) is directly mucked to ore passes fitted with grizzlys that have one-metre square openings. Ore containing small boulders (>1 m3, 3) is loader-trammed to ore passes fitted with rockbreakers. Medium-sized boulders (>2 m3) accessible from the drawpoint are drilled with Sandvik Tamrock Commando drills. Boulders hung-up within the drawbell are drilled and charged with a Sandvik Tamrock Secondary Breakage Unit. Compacted, fine-grained muck is blasted utilising 55 mm cartridge powder concussion bombs.

Jan 1, 2005

By X Dahe

SLon vertical ring and pulsating high gradient magnetic separators possess excellent mineral processing ability and have been widely applied to process oxidised iron ores. SLon centrifugal separators are applied to clean the SLon magnetic concentrate and remove quartz and other gangue minerals associated with a small portion of magnetite.This paper introduces the application of this technology in Hai Nan, Da Hong Shan and An Shan for processing oxidised iron ores.

Jul 11, 2011

By Swift D. G

For some time the Electricity Trust of South Australia (ETSA) has been investigating the application of new mining methods and equipment to minimise the cost impact of the steadily increasing depth of mining brought about by the 20¦ dip of the coal seams at the Leigh Creek Coalfield. Exhaustive examination of all suitable mining systems showed that highly mechanised systems involving belt conveyors displayed no eco- nomic or operational advantages over shovel and truck methods. However, the configuration of the Leigh Creek coalfield allows for two quite different approaches to mining by shovel and truck. The current strip mining method involves removing overburden from the highwall in 60 m to 200 m wide strips to progressively expose the coal down dip, and requires all waste to be hauled to the surface. The alternative ter- race haulback method involves opening a boxcut to full depth at one end of the coalfield, then mining the full section along strike and placing the spoil in the mined out area. On a strictly economic basis, the latter is clearly advantageous, but the former has significant less tangible advantages. In deciding between the two methods ETSA is faced with the need to examine the applicability of each method under a wide range of possible future demands on the coalfield, and to assess the importance of many intangible factors.

Jan 1, 1989

By Van Weert G

Ferrous chloride solution pyrohydrolysis is a successful IICI regeneration process which is carried out in either a spray roaster or a fluid bed. Pyrohydrolysis is not restricted to ferrous chloride only, every metal chloride can theoretically be hydrolysed. In practice, however, the conditions for ferrous chloride pyrohydrolysis differ from those of many non-ferrous metal chlorides eg zinc, lead and cadmium. Hence, a pyrohydrolyser could function as a ferrous/non-ferrous separator, eg an iron oxide and zinc chloride separator. Most pyrohydrolysers operate on solutions, in which case more than 50 per cent of the process energy is needed for heating and evaporating water. However, this disadvantage would be diminished by feeding a slurry to the reactor. Against this background it was decided to investigate the chloridisation of zinc ferrite which is an iron bearing solid with a non-ferrous impurity, and subject to processing and disposal problems. Synthetic zinc ferrite was chloridised in a tube furnace. The gas atmosphere in the tube furnace resembled that of a fluid bed pyrohydrolyser and consisted of HCI, 1120 and nitrogen. Gas composition, temperature, residence time and sample mass were varied. The experiments showed that complete (99.6 per cent) zinc extraction from synthetic zinc ferrite was possible in a simplified pyrohydrolyser atmosphere at 1100 K in four hours. The zinc ferrite was converted into gaseous zinc chloride, and hematite and magnetite solids. It was also found that zinc removal from the zinc ferrite lattice caused not only rccrystallisation of the zinc ferrite into hematite, but also hematite crystal

Jan 1, 1993

By A Thompson, E Villaescusa

The Western Australian School of Mines (WASM), Kalgoorlie, has been performing dynamic testing of reinforcement systems as part of the Minerals and Energy Research Institute of Western Australia (MERIWA) Projects M349 and M349A sponsored by WASM, the Western Australian State Government and the mining industry. These projects have resulted in the construction and commissioning of the WASM Dynamic Test Facility and a program of reinforcement system testing. The primary purpose of the WASM projects is to evaluate the performance of complete reinforcement systems when subjected to an axial dynamic load. The test procedure, monitoring and associated analysis enable assessments for each component (ie the element, the internal fixing mechanism and the surface hardware) of the reinforcement system. The performance of a reinforcement system is usually defined by a static force-displacement response to axial loading. However, this static response may not be applicable to dynamic loadings associated with violent failure of rock due to overstressing as mines progress to greater depths. It was therefore appropriate that the responses of reinforcement systems subjected to dynamic loading be defined and evaluated. The key findings from the tests on a number of reinforcement systems are presented and recommendations made regarding their application for dynamic loading.

Jan 1, 2008

By O Jones

Longstanding occupational health challenges of the underground hard-rock mining sector require both an analysis of historical data to assess evidence of linkages between the source of the problem and subsequent illnesses, as well as investigating the means by which health risks to workers can be eliminated or minimised. This paper refers briefly to a recently established National Health and Medical Research Council (NHMRC) sponsored Epidemiological Study into the incidence of Lung Cancer, contracted by mineworkers in Western Australia (WA) due to the inhalation of diesel exhaust fumes from 1996 to 2012. Thereafter it reviews current knowledge of the nature of the challenges facing those responsible for the health and wellbeing of underground hard-rock miners in WA, commencing with the recent categorisation of diesel exhaust as ‘Carcinogenic to Humans, Group 1’, by the World Health Organisation’s (WHO) International Agency for Research on Cancer (IARC). An attempt is also made to explore how the challenge has changed with the adoption of more advanced engine technologies, including the increased generation of ultra-fine volatile organic and other nucleates, submicron carbonaceous agglomerates and toxic gases.The compounding effect of using the mine decline access entry as both the primary ventilation intake and haulage-way is also discussed, as is the need to develop a more appropriate metric for regulating diesel engine emissions. Finally the paper refers to ongoing in-mine research pursued by the National Institute for Occupational Safety and Health (NIOSH) at its Diesel Laboratory in an underground limestone mine near Morgantown in the USA.CITATION:Jones, O, 2015. Diesel exhaust and the underground miner in Western Australia, in Proceedings The Australian Mine Ventilation Conference, pp 167–172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By L van Latum, A Koh, I Thomas

Haul truck drivers are at a high risk of developing fatigue due to the monotonous nature of the work and demanding shift rosters. In the mining industry, fatigue is identified as a major contributing factor in several fatal accidents a year. A number of fatigue detection devices are now available, that can contribute to improved fatigue risk management in the mining industry. This paper describes the technology and algorithms behind one particular product which is both predictive and un-obtrusive to the operator. The Advisory System for Tired Drivers (ASTiD), was developed by Fatigue Management International (FMI) in collaboration with the Loughborough Sleep Research Centre (LSRC), both in the United Kingdom. While this system includes a model of the human circadian rhythm as a bias for predicting expected fatigue risk by time of day, it also uses yaw data generated by a solid-state gyroscope in the horizontal plane. Algorithms analyse this data to determine the level of monotony of actual driving conditions and to detect changes in steering control caused by driver fatigue. During normal levels of attention, a haul truck driver applies continuous, small adjustments to the steering wheel. As the level of fatigue increases, steering adjustments become less frequent and more erratic. Differentiating between these modes of control in the highly variable mining environment is accomplished by chromatic processing of the gyroscope data. This paper will go into some detail explaining the principles behind chromatic processing and the specific application of these in detecting fatigue in haul truck operators.Technology in itself is not the solution to addressing operator fatigue, but it plays an important role in ongoing monitoring and maintaining awareness with mining personnel. Furthermore, the specific principles behind ASTiD technology support a risk-based approach to fatigue management, allowing optimisation of the mining operation for productivity as well as safety.

Sep 26, 2011

By R Hargreaves, C Morley

The authors often see problems on mine sites that are due to insufficient feedback between technical discipline silos as the realities on the ground fail to inform the models and plans used to drive resource exploitation. Resource modelling, reserve definition, life-of-mine planning, short-term mine planning and scheduling, mine operations and beneficiation operations are all processes that inform each other, but in many instances feedback between these processes occurs in an ad hoc way and only after problems have come to light.Universal reconciliation uses a multidisciplinary approach across the entire mining value chain to identify both opportunity and loss of value and to maximise operational performance. This paper will look at the operational effectiveness of universal reconciliation and will outline the important elements that make it successful, including how to map out the detail underpinning modelling, planning and execution processes. We do this by documenting the physical processes, logical work practices, organisational roles and responsibilities, data origin and quality, working assumptions and information management practices at an operation. The results quickly show how misinformation and assumption causes suboptimal decisions to be taken, where inefficiencies exist and what the opportunity is to remedy these issues.A universal reconciliation study opens up an opportunity for stakeholders to reassess how the operation should be run and how operational effectiveness should be measured. Clear envelopes for reconciliation become obvious and questions about the practicality and data quality can be addressed.A reconciliation code of practice is a key element of a successful universal reconciliation project and the authors outline the important aspects that will provide an operating model, showing the effectiveness of the resource and reserve modelling, the practicality of the mine planning and scheduling practices, how well the mine operations team are executing these schedules and how effective the processing area is given what it is fed. Most importantly, a system that allows operations time to react before the losses become systemic and that is based on identifying early warnings from hard data when these processes start to wobble is outlined. Finally as a case study, the revenue and cost benefits resulting from universal reconciliation diagnostic projects for nine mine sites is documented.CITATION:Hargreaves, R and Morley, C, 2014. Universal reconciliation – a multidisciplinary approach across the entire mining value chain to identify loss of value and maximise operational performance, in Proceedings Ninth International Mining Geology Conference 2014 , pp 411–420 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By T X. Le, H T. Tran, K Zaw, T Manaka

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Truong Son fold-thrust belt (TSFTB) is a prominent tectonic component of mainland Indochina that occurs as a north-west–south-east-trending tectonic entity that extends from north-eastern Laos, straddles the Laos-Vietnam border area and is submerged under the sea basin in east central Vietnam. The TSFTB hosts numerous regional-scale gold and polymetallic base metal deposits, and the mineralisation occurs along the strike of the belt; however, the potential of many of these deposits are inadequately evaluated. The ore mineralisation is hosted by different rock assemblages, including highly metamorphosed Late Proterozoic metasedimentary rocks and Palaeozoic sedimentary and/or volcanic packages, which were intruded by several phases of magma and underwent a number of tectonic events. Several ore-forming styles – including porphyry, Carlin-type and sediment-hosted orogenic Au – were formed during at least two phases of regional thermotectonism that have been identified in the TSFTB. However, all of the major gold deposits/mineralisations are closely related to region-wide structural breaks and many of them are controlled by large-scale, high-strain zones. The fold-thrust structures in the TSFTB therefore play important roles for regional gold mineralisation and metallogeny.CITATION:Tran, H T, Zaw, K, Le, T X and Manaka, T, 2015. Structural controls on gold mineralisation in the south-eastern Truong Son fold-thrust belt and its significance in regional metallogeny, in Proceedings PACRIM 2015 Congress, pp 521–530 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

This paper examines some of the important aspects of mineral taxation policies and practices, with reference to the mining tax regimes of selected Pacific Rim countries (see Tables 1 and 2). The following subjects are addressed:what is æmineral taxationÆ?, basis for mineral taxation, types of mineral taxes, objectives of the mineral taxation regime, best practices, and mineral royalties. Many countries, in some cases with the encouragement and assistance of international funding agencies, are actively assessing the international competitiveness of their mining tax regimes with a view to attracting investment. However, these countries recognise that the mining tax regime is not the only consideration that is taken into account by prospective investors. The countryÆs geological prospectivity, physical infrastructure, labour force, political risk, and regulatory system are also important factors in the investment decision making process. Although it is probably true that an attractive mining tax regime will not necessarily attract mineral investment, there is a real possibility that an unattractive regime can drive away investment. For example, Hugo Dummett, general manager for discovery at BHP, hinted recently that BHP could cease exploration in Russia in the absence of positive tax changes. Dummett is reported as saying that if taxes æend up being as onerous as they are now, we really have to rethink why we are hereÆ (Mining Journal, London, November 27, 1998).

Jan 1, 1999