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By J. Hamisch

Climate policy regarding perfluorocarbons (PFCs) may have a significant influence on investment decisions in the production of primary aluminum. This work demonstrates an integrated analysis of the effectiveness and likely economic consequences of different climate policy options. In our study we first compare atmospheric observations to the available estimates of PFC emissions for the baseline years 1990 and 1995. We then present projections for regional emissions of PFCs from the aluminum industry using the MIT Emissions Projection and Policy Analysis model under different policy scenarios. Abatement costs for emissions of PFCs and C02 are compared in the context of the Kyoto Protocol.

Jan 1, 1999

The Graham Farmer Freeway Project in Perth, Western Australia, is the largest urban infrastructure project ever carried out in the State. At a project cost of over $360 million, it also ranks as one of the largest in Australia and is even large by world class standards. The project provides a much needed east-west freeway bypass around the CBD of Perth, linking the Great Eastern Highway in the east with the Kwinana and Mitchell Freeway system in the west. The Bypass will have 6.5 kilometres of freeway, a major bridge over the Swan River, several pedestrian overpasses and underpasses, dual use paths, interchanges and flyover bridges and a rail tunnel. The whole project is being carried out over a four-year time frame, due to be complete and open to traffic in June 2000. The project has been divided into two stages, with Stage 1 including the 1.63 kilometre long Northbridge Tunnel, the subject of this paper.

Jan 1, 1999

By Chr. Kersch

This project further develops supercritlcal fluid extraction as an industrial soil remediation process. Heavy metals are removed from sand using CO2, The effect of the type of complexing ligands, pressure and water content on the extraction efficiency is investigated.

Jan 1, 1999

By J. E. Lees

Advanced remote sensing can be a powerful new information tool to help private and public entities make better environmental and resource management decisions. However, some regulated entities are reluctant to develop or use this tool because of their concerns that it will lead to increased risks and costs of environmental legal liability. They fear that new ways of monitoring the environment will increase liability, undermine existing enforcement agreements, reopen compliance agreements, and generally provide a competitive disadvantage to early adopters by accelerating environmental cleanup costs. Others counter that the increased risks are marginal, and that several advantages outweigh these risks, including the opportunity to more effectively manage environmental operations, target and set priorities, measure and track management and compliance effectiveness, provide more defensible environmental assessments and baseline conditions, make and defend optimal siting decisions, and avoid or resolve environmental disputes. This paper offers strategic advice on ways regulated entities can enjoy the benefits of these powerful new information tools while mitigating down-side legal and compliance risks as much as possible.

Jan 1, 1999

By K Le Bron

Fatalities that occurred because of rock falls in off-reef excavations (excluding shafts) over the last three years range between ten per cent and 20 per cent of the total number of fatalities that have occurred due to rock falls in the South African mining industry. These rock falls, mostly exacerbated by blasting practices, occur because of failure on discontinuities within the rock mass. Among other reasons of their occurrence is insufficient support installation or the incorrect assessment of rock mass conditions. This report presents qualitative analysis intended to outline rock stability conditions in tunnels subjected to dynamic loading. Seismic waves including those created by firing an explosive charge in tunnel rocks are considered. The rock behaviour is monitored using geophones and extensometers variably installed to record the near and far effects of roof bolt support units on a dynamically loaded rock. The paper discusses the results of field investigations.

Jan 1, 1999

By R. Schaller, Ch. Karcher, A. Thess

"Electron beam evaporation of liquid metals is an innovative technology increasingly used in industry to produce very thin coatings of high purity. In this process the surface of a metal ingot, placed in a water-cooled copper crucible, is heated by bombarding it with a high-energy electron beam gun. The material melts, forming a free surface and eventually starting to evaporate. The rising vapor cloud condensates as a thin film on a moving substrate. The strong energy input at the free surface gives rise to vigorous thermos capillary and buoyancy driven convective motion within the melt, leading to unwelcome heat losses. This paper aims to show how these losses can be reduced by optimizing the geometry of the crucible and by using external magnetic fields. We present both experimental and numerical results.IntroductionElectron beam evaporation of liquid metals [l] is an innovative PVD-technology which is excellently suited for the industrial production of high-quality coatings. In this vacuum process a high-energy electron beam heats up the surface of a metal ingot. The ingot melts and forms a free surface. A schematic view of the arrangement is shown in Figure 1. When the temperature of the free surface exceeds the actual (pressure-dependent) saturation temperature of the ambient gas, the liquid starts to vaporize. The rising vapor cloud finally condensates on a moving substrate located at some distance above. To guarantee a superior quality of the coating the melt is typically confined in a water-cooled copper crucible. The intensive cooling is necessary to avoid chemical reactions between the melt and the crucible walls, that is, crucible materials and their reaction products are practically excluded from evaporation."

Jan 1, 1999

Column flotation cells continue to gain acceptance in the coal industry for the treatment of high-ash streams containing clay slimes. Unfortunately, some industrial installations have failed to meet expectations due to improper scale-up, incorrect operation and poor ancillary circuit design. To overcome these problems, case studies have been conducted to fully define the capabilities of column cells for coal applications. These data have been used to develop generic engineering guidelines for column circuit design and operation. An economic analysis has also been conducted to illustrate the importance of key capital cost considerations. These analyses indicate that column cells are significantly more expensive than conventional machines, although this difference can be greatly reduced through the installation of very large-diameter columns.

Jan 1, 1999

With commodities suffering dramatically low real prices, mining business margins are under intense scrutiny. Unfortunately, management systems developed early this century for manufacturing are driving counterproductive behaviours that choke productivity. The paper and presentation will explain this and present a proven methodology for increasing productivity. This will be supported by operational examples from Australian and American mining management to demonstrate the importance of modern business performance measurement and analysis systems. It will explain the importance of management systems in driving organisational change to sustain superior productivity and margins. The paper will explain why many executives and managers confuse production (a measure of volume) with productivity (which measures efficiency and effectiveness). It will explain how this and other counterproductive managerial and operator behaviours and attitudes are driven by traditional business management systems exacerbated by managerial and consulting fads. The paper will begin with the simple principle that to improve results one needs to first improve the process producing the result û and will show how this is often violated. Improving productivity then boils down to:accurately identifying opportunities using sound, modern measurement, analysis and reporting systems; methodically improving operating and commercial processes, and changing peopleÆs behaviours and attitudes to sustain changes in practices. The paper will include fundamentals of applying sound measurement and analysis to:processes directly, eg cycle time charts and their impact in cyclical (non-continuous) operations commonly used in rock breakage; drivers of productivity; and process results themselves since correct analysis identifies opportunities accurately. The paper will cover the importance of practical leadership and the need to follow a simple, solid plan for changing systems that drive behaviour. Overall, it will highlight use of modern performance Measurement, Analysis and Reporting systems to drive behaviours and improve margins - without capital investment û and make executive and managerial work easier and more effective.

Jan 1, 1999

By K. Hanna

Early identification of adverse geologic conditions and high stress concentrations during the high-speed extraction of coal using modern mechanized long wall systems is a major challenge facing the mining industry. Often, unexpected geologic anomalies that affect rock mass quality are encountered more rapidly, leaving the mine operator with insufficient time or information to deal with the changing ground conditions. The RockVision3DTM seismic tomographic system, developed by NSA Engineering, Inc., offers substantial benefits over conventional geologic/stress-detection methods and has been used successfully in coal mines worldwide. Tomographic images, produced economically and in near-real time, are easy to interpret, allowing mine operators to deal with potential hazards on a day-to-day basis. This paper focuses on the application of RockVision3DTM technology for delineating hazards caused by stress and geologic anomalies. Case studies for two bump-prone coal mines will be discussed. For example, (1) in a German deep (>1,130 m) mine, the drilling-yield method was used to verify the effectiveness of this technology in detecting stress anomalies ahead of longwalling; (2) in a Polish mine (-500 m deep), two longwall panels 4 km apart were monitored to assess structural and stress-related factors contributing to differences in mining conditions and magnitude of structural failures.

Jan 1, 1999

An important problem in mine operations is the classification of material as waste, low-grade stockpile, and ore. This classification must often be made with blasthole data that are widely spaced and that have sampling errors. Geo-statistical simulation techniques combined with basic economic principles allows a procedure for classification that maximizes expected profit. Geostatistical simulation methods (Gaussian, indicator, or annealing-based) allow the integration of hard and soft data in the creation of alternative, equally-probable, realizations of the mineral grade(s). At each location, for each realization, we calculate the "profit" if the block were to be classified as ore or waste The optimal classification is the one that maximizes expected profit (a Maximum Profit Se-lection (MPS) procedure). We discuss the theoretical justification of the method and implementation details. The use of blasthole data from different types of mineral deposits, that is, different levels of continuity, is considered. We also show the efficacy of the procedure with different levels of sampling error. The increased revenue due to the MPS procedure and improved sampling is shown. We show the geostatistical simulation procedure and the uncertainty in block grades that result from incomplete and imperfect sampling. The optimal classification is presented. Optimal block classifications are transferred to realizable dig-limits by hand-drawing polygonal boundaries. We compare the results of the proposed method to classification based on kriging. Limitations and areas of future work are identified.

Jan 1, 1999

By J. O. Costello

Marble is a preferred surfacing material in up-scale buildings. Its use increased in the 1870's with rising national wealth and declined in the 1950's when synthetic materials for these applications were developed. Natural marble is now limited to high-end domestic and commercial structures. Cultured marble is a paste of white marble dust and polyester resin cured in molds yielding fixtures of specific finished dimensions. Dyes incorporated at different stages in the mixing cycle mimic shades and veining of natural marble. This paper discusses the filler requirements for cultured marble production and reviews new techniques to cut and finish natural marble.

Jan 1, 1999

By E. Costa Silva

Among the methods of mineral processing, gravity concentration methods are, probably, those which have lower costs, higher capacities and lower operational complexity. In order to be really effective, these methods require a feed size distribution in which the particles are liberated. Further, there must be a significant difference (usually higher than 1-1.5) among the real densities of the particles. However, in most cases, the traditional gravity concentrators (jigs, shaking tables, spirals and dense medium hydrocyclones) lose efficiency (sharpness of cut and recovery) when the mean diameter of particles are lower than 0.05mm and the difference among densities are smaller than 1. Most gravity concentrators developed in the last 20 years are based on the use of centrifugal forces that create large "apparent gravitational gradient" seeking to overcome the limitations of particles size distribution. This paper presents the experience of the CVRD Research Center in evaluation and development of new process based on using this new generation of gravity concentrators.

Jan 1, 1999

This paper has been developed for æThe Race for SpaceÆ conference. It ranges over various aspects, all of which are within the umbrella of marketing. The question is posed because many engineers, tunnelling and other specialisations, frequently demonstrate an unwillingness to embrace marketing. The accurate reply is probably à ænot an engineer!Æ The paper identifies some of the possible explanations for this reply. The vast majority of the themes, ideas and principles are based on more than 25 years actual experience for the author with Engineers, Tunnelling and other disciplines. This experience has been gained with leading consulting engineering practices; some of the worldÆs largest construction contractors together with other organisations employing engineers in the public, private and tertiary sectors in the UK; US; Europe; the Middle East and throughout Australia and New Zealand. Experience has been gained in design offices; head offices and construction job sites in four contrasting continents. The most significant themes developed throughout this paper are as follows:æLetÆs go and do some ærealÆ work and leave the marketing to others!ÆæMarketing is just a æsoftÆ option and neither technically based nor true management!ÆNIMBY-ism (Not In My Back Yard) so leave well alone!Engineers regularly confuse services marketing -v- product marketing à a useful cop out, or a genuine cry for help?Marketing databasesæLetÆs get rid of the term æsellingÆ and replace it with the more acceptable à and less distracting for tunnelling engineers à 'marketingÆDistinction between benefits and features à in The Race for SpaceSales Comprehension Test, Benchmarking TestJack WelshÆs æmost difficult decision for a CEOÆHarvard Business ReviewÆs (HBRÆs) formula for performanceMany engineers are losing the balance in their lives Sustainable development and engineering æQuality work doesnÆt mean quality serviceÆMajor recommendationsRecommended references

Jan 1, 1999

By Leslie F. Ruppert

The US Geological Survey (USGS) is currently conducting a coal resource assessment of the coalbeds and zones that are projected to provide the bulk of the nation’s resources for the next few decades. The Pittsburgh and Upper Freeport coals are the first two beds in the northern and central Appalachian basin region to undergo fully digital coal assessments. The bed-specific assessments are being carried out in partnership with the state geologic surveys of West Virginia, Ohio, Pennsylvania and Maryland. Comprehensive stratigraphic and geochemical databases have been developed for both of the beds. The extent of the bed with mined areas, structure contour, isopach, and overburden thickness maps for the Pittsburgh coal bed have been released as USGS open-file reports.

Jan 1, 1999

By A. T. Iannacchione

Underground stone mining represents an emerging sector for the U.S. mining industry. As this expansion takes mines under deeper cover and as more efficient mining methods are utilized, adequate stone pillar design methods will become more important. It is the purpose of this paper to examine current design practices and to discuss issues for safe mine layouts so that a rational first approach towards balancing the demands for increased production can be weighed against increased risk to worker safety from rib instabilities and pillar failures. Seventy-two stone mine pillar designs were examined. Pillars with width-to- height ratios below 1.5 and subjected to excessive stress levels appear more likely to fail. When width-to- height ratios fall below 1 .0, defects in the pillars, such as through-going discontinuities, can have a significant influence on stability. Discontinuity persistence, dip, material properties, and orientation are important factors controlling pillar strength. The influence of discontinuity dip, a characteristic easily identified in the field, was examined so that its presence could be accounted for in developing generalized guidelines for pillar design.

Jan 1, 1999

By K. Y. Haramy, K. Hanna

Early identification of adverse geologic conditions and high stress concentrations during the high-speed extraction of coal using modern mechanized longwall systems is a major challenge facing the mining industry. Often, unexpected geologic anomalies that affect rock mass quality are encountered more rapidly, leaving the mine operator with insufficient time or information to deal with the changing ground conditions. The RockVision3D™ seismic tomographic system, developed by NSA Engineering, Inc., offers substantial benefits over conventional geologic/stress-detection methods and has been used successfully in coal mines worldwide. Tomographic images, produced economically and in near-real time, are easy to interpret, allowing mine operators to deal with potential hazards on a day-to-day basis.

Jan 1, 1999

By W. L. Hollinshead

For more effective and cost saving production in tunnels, the machinery used on construction sites will be equipped with guidance systems combined with working procedure management systems. This paper describes sensors for these systems and various system configurations. A project is described which uses a computerized guidance system on an underground mining machine for guidance and profile control.

Jan 1, 1999

By Norman R. Ball

"Many people in the mining and metallurgical industries were brought up to embrace Henry Ford's pronouncement that ""History is bunk"" but it is not generally known that the same Henry Ford created and paid for one of the finest technological museums in the Western World. I am aware that many people feel that industry history is something you ask aging executives to do or that history is a clip-andpaste compendium of pictures re-discovered every 25 years or on the occasion of issuing a press release on plant expansion. Moreover, there are many who fear historians as somewhat deranged individuals interested only in corruption, injustice and sensational labour strife. Good history lies somewhere between the controlled P.R. handout and the hysterical attack. Writing good history is a difficult creative act based on the application of experience, insight, wide knowledge and careful reasoning to available evidence. To date, the Canadian mining and metallurgical industries have achieved a great deal but left too little evidence and it is this lack of evidence which must be corrected before it is too late. It is the purpose of this article to stimulate thoughts with regard to archives, one of the more important vehicles for the preservation of such evidence."

Jan 1, 1999

By Michael A. Lllga

Electrically Switched Ion Exchange (ESIX) is an approach for ion separation that combines Ion exchange (IX) and electrochemistry by utilizing electro active IX films to provide a selective, reversible, and economical separation method that greatly reduces secondary waste generation compared with conventional ion exchange. Studies on the development of films with improved stability and capacity and their use in continuous flow systems for ion separations will be. reported. Both technical and economic evaluations demonstrate ,the viability of once-through or batch recycle waste processing with ESIX.

Jan 1, 1999

By R. M. Cox

Pneumatic coal loading and conveying systems provide alternative methods for the safe and efficient mining of the thin high-grade coal seams found in the Southern Appalachians. Pneumatic systems eliminate most of the health and safety hazards associated with the operation of conventional mining and haulage equipment in small low-coal mines by removing powered mobile equipment from the mine. Ventilation is also improved by the coincidental removal of gas and respirable dust from the mine by the operation of the pneumatic loading and conveying system. Other significant advantages of pneumatic coal recovery systems are relative simplicity, operating flexibility, low capital cost, quiet operations, environmental benefits, and ease of automation. The design considerations and field evaluations of experimental prototype pneumatic coal loading and conveying systems, installed and operated in small thin-seam mines, are presented in this report. In addition, fundamental design criteria and recommendations for the installation and operation of a variety of pneumatic coal loading and conveying systems are proposed, which offer alternative coal recovery systems that alleviate the serious health and safety concerns of current small mine operations.

Jan 1, 1999