Search Documents

The key aspects of process metallurgy that distinguish platinum group metal (PGM) concentrate smelting from that of other base metal sulphide concentrates are presented. These differences include considerably higher input chrome and magnesia contents that directly raise the slag liquidus temperature and have the potential to increase accumulations of refractory spinels. Most importantly, the higher processing temperature required for PGM smelting and the resulting very high matte superheat lead to considerably more onerous smelting conditions than those typical of other smelting operations. This has presented challenges to furnace design and integrity, especially when coupled with the progressive intensification of smelting, involving doubling, and then redoubling, of furnace power inputs over the past 20 years. These power increases have been enabled by increasingly more advanced furnace cooling and structural technologies. Key technologies include strong constant-force spring-loaded bindings acting in three dimensions to minimize infiltration of superheated matte into brick joints, and robust well-cooled tapholes for reliably tapping the superheated matte. The result has been substantially improved productivity, and reduced smelting capital cost outlay per unit of production. A significant challenge, which was not anticipated, presented itself in the form of insidious corrosion of the furnace lining, and especially high-intensity copper cooling elements. Investigation of corrosion in related industries eventually identified chloride-accelerated sulphidation', and this term has been retained as it generically describes the most pertinent aspects of the accelerated low-temperature wear of copper coolers observed in PGM smelting. In addition to discussing the corrosion mechanism, this paper describes a number of solutions that were developed jointly by Anglo American Platinum and Hatch to address the copper corrosion problem. First, new monitoring technologies allowed furnaces to be operated more safely for a longer period of time. Second, a system for replacing corroded coolers from outside the furnace during a fast 'hot' shutdown minimized the impact on furnace operating factor and hearth life. Finally, a corrosion-resistant graphite-protected cooler design significantly improved furnace campaign life, and heralds a more lasting solution to cooler corrosion in PGM furnaces.

Jan 1, 2013

By Jeremy Morris

The city of Indianapolis has more than 25,000 homes currently on septic systems. Many of these systems do not function well because of their age and surrounding soil conditions. As Indianapolis has worked to eliminate septic systems and install sanitary sewers in large unsewered areas on the north-west side, capacity of the existing Belmont North Interceptor (BNI) became a concern. The BNI system currently services an area of approximately 80 km2 (31 sq miles) located within the northwest quadrant of the city (Fig. 1). Monitoring of the existing interceptor indicated portions of the sys-tem flowing half- to two-thirds full during dry weather conditions and surcharging during some wet weather conditions. Further analysis of the BNI based on growth projections coupled with increased sewershed yield resulting from the city?s septic tank elimination program (STEP) indicated dry-weather flows could potentially triple over the next 20 years. Based on these modeling results and current wet weather capacity issues, the city determined further STEP projects could not be performed within the BNI service area until

Jan 1, 2011

By A. D. Dalvi

With the current economic situation, the demand for nickel and other base metals has fallen significantly. More than 440 kt/yr world nickel capacity has been taken out of production within the last year, or more than 25% of the total [1]. This situation is similar to that at the end of 1970?s and it will take a number of years for the demand to recover to the levels before the economic downturn. In the meantime, the challenges facing the industry have increased due to diminishing ore grades, more inaccessible and complex deposits, mounting capital and operating costs and the various external pressures which include socio-economic, environmental, and energy challenges. All industries will be faced with paying the ?total ownership costs? in the future. This will only increase the burden on the industry. How to cope with this in what Thomas Friedman calls the ?Energy-Climate Era? [2] will be the most pressing challenge for the next generation of metallurgists and managers. It will force us to take a broader view of the problems and the solutions beyond mere technical. The metallurgists, engineers and project managers will have to look at the overall projects and their objectives in designing the solutions, requiring a top-down strategic approach.

Jan 1, 2009

By K. V. Raj

In the mining industry, computational fluid dynamics (CFD) modeling is used extensively to simulate air flow in underground mines. CFD modeling of pollutant transport in open-pit mines is relatively new. Modeling the actual pit geometry of an open-pit mine and the open domain is complex. The complexity is primarily due to the faceted geometry of an open-pit mine with its numerous associated sharp features. Important issues that are not considered carefully at the geometry level are generally propagated to the subsequent processes. Several challenges and pitfalls are encountered in modeling pollutant transport in open-pit mines. These challenges and pitfalls are related to the geometry, meshing, boundary conditions, and turbulence modeling parameterization. An appropriate mesh selection is critical. A detail discussion of the meshing of the domain of an open-pit mine is presented in this paper. The selection of an appropriate turbulence model, such as kappa-epsilon (?-e), large eddy simulation (LES), Reynolds stress model (RSM), etc., to obtain the best possible solution is equally significant. This paper discusses the various challenges in modeling the pollutant transport process in an open pit and some of the approaches adopted to address these challenges.

Feb 27, 2013

By J. Haynes

Coal mines in the eastern US often use sloped shafts as production beltways for ore removal, as means of access for supplies, and for ventilation. These structures are usually completed with the help of a contractor. In late 2011, Frontier-Kemper Constructors was engaged to build a slope for a coal mine in southern Indiana. Although the site was located in familiar Illinois basin formations, the geology proved to be very difficult. This paper describes some of the challenges faced during excavation of this slope and the methods used to overcome them, including changing the method from conventional drill and blast to cutting with a continuous miner.

Feb 27, 2013

By P Allen, E Gleeson, D Boakye, R Chesher, S Konopa

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Not only do epithermal gold deposits provide many challenges in estimating mineral resources, the complexities of these deposits also provide technical challenges in assessing appropriate mining and processing strategies, as well as social and environmental planning and management. The characteristics of epithermal gold deposits include being highly variable with respect to geometry and gold grade distribution, the presence of other economic contributors, mineralogy, texture, rock strength, weathering and alteration overprint. These characteristics influence the economic value of mining projects in an interlinked manner. Consequently, successful exploitation of epithermal deposits requires a holistic approach, coupled with the effective integration of geological data to meet all aspects of mine development decision-making. This paper presents examples of the key technical challenges encountered in estimating and mining epithermal deposits. It also highlights why these issues need to be addressed from the viewpoint of geology, sampling, resource estimation, mine planning, mineral processing and social and environmental planning for the true value of the mining project to be realised.CITATION:Konopa, S, Chesher, R, Gleeson, E, Allen, P and Boakye, D, 2015. Challenges in maximising the value from epithermal gold deposits, in Proceedings PACRIM 2015 Congress, pp 127–132 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A. D. S. Gillies

Inertisation is used to enhance the safety of underground mine areas either to avoid the potential for a combustion event or to stabilize a situation after an ignition, fire or heating. The primary objective of a recently completed Australian Coal Association Research Program (ACARP) study was to review coal mine inertisation and in particular to focus on use of the Polish mine fire simulation software Ventgraph to gain better understanding of how various inertisation units interact with the complex ventilation behavior underground during a substantial fire. Critical aspects targeted for examination under the project grant included location of the unit for high priority fire positions, size of borehole or pipe range required, time required for inertisation output to interact with and extinguish a fire, effects of seam gases on fire behavior with inertisation present and main fan management. A major accomplishment of the project has been to take findings from the simulation exercises to develop inertisation related modifications to the Ventgraph fire simulation program in conjunction with the Polish program authors. Selected mines were ?evaluated or audited?as to the ability to deliver inert gases generated from GAG units to high priority underground fire locations .A coding system has been developed and many potential underground mine fire sources cannot be successfully inertized with the GAG docked at the current specified point; this is particularly so for fires in extended areas of workings or in panels. There is a limit to the ability of the GAG jet engine to deliver exhaust down smaller dimension borehole. There is a need to examine the use of the GAG for production or proactive uses in a wider application in Australian mines responding to recovering from mine fires, spontaneous combustion heating?s, elimination of the potential explosibility of newly sealed gobs or inert mines or mine sections on closure. Some of the current uses of low flow inertisation facilities could be more effectively undertaken with the GAG unit.

Jan 1, 2009

By Marco Sonnenschein

As time is costly, engineering companies have developed methods, procedures and mechanical equipment to tunnel faster. But the best excavation method will not be able to cope with the time pressure if there is not a reliable backup system. Therefore, the application of belt conveyors for tunnel boring machine (TBM) drives as well as for drill-and-blast driven tunnels assure a quick and smooth removal of excavated soil in order to enhance the efficiency of the tunneling equipment. During the last 10 years, belt conveyor systems have achieved ?state-of-the-art? levels and have become the first choice for muck removal systems in both TBM and drill-and-blast driven tunnels. Because time has become such a key criterion in tunneling projects, it is essential that all equipment is operated so as to derive optimum efficiency and minimize costs. Efficiency also means to think about new tasks for existing technologies.

Jan 1, 2012

By A. P. Schissler

Mining has several characteristics, uncommon in other business sectors, which pose additional challenges to the implementation or design of IT and management systems that use the information. Understanding these characteristics would improve the chances of successfully importing new information technology and management techniques to mineral producers. The most important characteristics that should be understood are workplace issues, the industry’s dual nature of being a continuous construction project using cyclical factory processes, labour challenges, workplace culture, information availability, integrative data elements, and the current technical education of mining engineers. These characteristics were taken into account in two applications of information technology and systems design at operating companies. The research and consulting projects focused on the development of an IT-enabled performance management system at several underground metal mines in Canada and an integrated data warehouse for surface mines spread throughout the United States and Latin America.

Jan 1, 2006

By J. Jeffrey Wagner, Michael J. Bailey, Peter M. Douglass

The Chambers Creek Interceptor Sewer Tunnel project consisted of 2-1/2 miles (4 kilometres) of nominal 9-foot (2.7-metre) O.D. tunnel driven through predominantly glacially overridden soils. Mole-Collucio Construction Company initially elected to drive the entire tunnel with a Lovat TBM. However, this machine could not control the fast raveling ground conditions which developed when the TBM encountered sands overlying very dense, hard glacial till or boulders. As a result, a shield and digger machine was brought in for a 1700-foot (518-metre) long segment. Pumped wells spaced roughly 50 to 125 feet (15 to 38 metres) apart were utilized to dewater about two-thirds of the alignment during construction. Initial support consisted of steel ribs and wood lagging, with a final lining comprised of pre-cast concrete pipe segments grouted in place.

Jan 1, 1985

By J. D. Bliss, G. J. Orris, W. O. Menzie

"Analysis of gold placer data from gold placers throughout the world suggests that gold grades and volumes cannot be used to distinguish between most types of gold placers. Only the alluvial plain and fan placers are significantly different among the types of gold placers considered. Gold grades and volumes change when working gold placers go from small-volume methods to large-volume methods. The small-volume methods are either of the surface or subsurface (drift mining) type. The odds that a gold placer will be dominantly worked using small volume methods at the surface are about 5:3. Once small volume mining has occurred, the odds against subsequent large-volume mining are about 4:1. If a placer deposit is suitable for large-volume mining, and the amount of gold produced from small-volume mining was reported, an estimate of the remaining gold (log10kg) can be made using the following equation:The relationship shown by this equation suggests that very large gold placers have over half their total gold content in the rich gravels appropriate for small-volume mining. These relationships in conjunction with other data and computer simulation can be used to estimate placer gold resources for an area targeted for mineral resource assessment. IntroductionGold placers have been an important source of gold throughout man's history and may have been one of the first sources-dating back to around 6000 B.C. (Gregory, 1980). From the primitive basket to the modern floating dredge, a variety of methods have been used to work gold placers. Placers are found in a wide spectrum of geologic and climatic settings. They have been classified by using a mixed set of criteria including age (Recent, Tertiary), climate (desert), fluvial position (modern channel, bench, alluvial fan), environment of deposition (eluvial, alluvial, residual, beach), type of transport (stream, wind, glacier), and whether the placer is buried or at the surface (Boyle, 1979; Wells, 1969). Several mining methods have usually been used to extract gold from anyone placer."

Jan 1, 1987

Interest in mining narrow, vein-type ones has increased world-wide during the last few years despite the fact that prices of metals have not risen in proportion as production costs of mining, such as labour and energy. In many mines, where narrow ones are mined, the mining technique and equipment used have been poorly mechanised. The mining methods have been cut-and-fill or shrinkage stoping. Pneumatic jack-legs have been used for drilling and slushers have been used for loading. The methods that have been used can be called the 'first-generation' methods. Work has been very hard for miners. It has been dangerous and exhausting. Production volumes of mines, and a s a result of that, also profits have been low.

Jan 1, 1990

By Guoqi He

Common offset seismic data collected over two active longwall panels at different stages of mining reveal that significant arrival time delays are produced in reflections from different levels within the mine cover. Mining-induced arrival time delays are also observed beyond the edges of the mine over unmined areas. Reflection arrival time delays increase with reflector depth and are laterally variable. The arrival time delays are produced by reductions of seismic velocity within the overburden. Reflection arrival time delays from a major strong unit located neutrally within the cover are proportional to subsidence, however, delays in other events are not.

Jan 1, 1989

By Frank B. Amon

Highland Valley Copper had to make some significant changes in the way it was working in order to counter the effects of ever-increasing costs and decreasing metal prices. A mine/mill optimization plan started in 1997 introduced new technologies and management approaches that resulted in a dramatic drop in cash breakeven costs. The changes involved employee training, added authority and responsibility for staff, better communications, and a consistent approach to setting and achieving property-wide goals. The net effect was to change the culture of the organization from one that was fragmented and focussed on local objectives to one that is cohesive and has common goals. These changes have allowed the mine to remain in business during a protracted period of low metal prices, and have positioned the mine favourably to benefit even more from any future increase in prices.

May 1, 2004

By J. L. Viljoen

t has long been the drive of the industry and all operations to create an environment that is free of injury and illness. We have come a long way; the leaders, executives, managers, supervisors and workers are to be commended for relentlessly driving to create, what I call a ?White Flag Day Every Day?. Yet I am also aware of the huge shift we still need to create in the industry, on the operations and in the workplaces to have them free of injury and illness. Keywords People, values, care, trust, belief.

Jan 1, 2011

By R P. Bewick

Many future and current block and panel caves extract ore from veined rock masses. These rock masses are composed of open joints forming blocks or rock with healed networks of veinlets. These two types of discontinuities pose a challenge for rock mass characterisation and classification due to difficulties in distinguishing actually open joints from healed but weak veins when diamond core drilling and excavation blasting practices disturb the rock mass. The inability of separating characteristics of open joints and healed veins has often resulted in an underestimation of the rock mass quality and as a consequence led to inappropriate assessments of rock mass response to mining (ie rock mass behaviour) and consequently deficient excavation stability assessments and ground support designs. In this paper, guidelines are provided to improve the characterisation and classification of veined rock masses. It is shown how veined rock masses can be mischaracterised resulting in often incorrect forecasting of rock mass behaviour. Following this, the classification of veined rock masses is examined. It is shown how the primary classification systems (ie Q – Barton, Lien and Lunde, 1974; rock mass rating (RMR) – Bieniawski, 1976) may not lead to reliable ratings in veined rock masses if care is not taken to differentiate between open joints and veins of varying strength. Examples are provided to illustrate how the Q and RMR systems are insensitive to veining. Finally, an example of characterising a veined rock mass for design purposes is presented.CITATION:Bewick, R P and Kaiser, P K, 2016. Characterisation and classification of veined rocks for rock mass behaviour assessment, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 825–834 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By R Munoz, R González, J Vallejos, A Delonca

In panel caving in underground mines, it is essential to characterise and monitor the stress and stability state of production level pillars to ensure the extraction of the mineralised ore column and the safety of workers. Pilar Norte is a sector in the El Teniente mine that forms a pillar between the undercut fronts of the adjacent Esmeralda and Reservas Norte sectors. It exists in a high-stress environment, which may induce damage to the rock mass production pillars. Generally, numerical models are calibrated using observed damage in galleries. This procedure does not discriminate between the structural condition and/or the blasting damage effects. This paper proposes a technique that uses borehole cameras to measure stress-induced damage. This has the advantage of being at the intact rock scale, meaning that the effect of geological structures is negligible and the blasting damage factor is eliminated. Comprehensive geotechnical characterisation and tomography monitoring has been undertaken at Pilar Norte to describe and determine the rock mass behaviour of the production pillars. By combining analytical, empirical and numerical models, a correlation between the measured overbreak recorded by the borehole cameras and the stress level of the pillar was developed. The methodology can be routinely applied to estimate the stress state in the production pillars.CITATION:González, R, Munoz, R, Vallejos, J and Delonca, A, 2016. Characterisation and monitoring of the stress state of production pillars at El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 197–202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A. S. W. Kurny, M. Z. Huq

Bangladesh ilmenite is partially altered, containing pseudorutile, rutile and haematite as well as the predominant ilmenite phase. A typical analysis is 39.45% TiO2, 24.19% FeO and 33.0% Fe2O3. Reduction of the ilmenite by charcoal was found to involve two major reactions: conversion of pseudorutile into ilmenite and rutile, and change of ilmenite into metallic iron and rutile. The first, which was much the faster reaction, was responsible for an initial increase in ilmenite content with reduction time at lower temperatures. Apart from these two major reactions, rutile was reduced to lower oxides at 1 100 degrees C with a consequent decrease in its XRD peak height

Jun 19, 1905

By D Nobes, D Trumm, D Manhire, A OÆSullivan, M W. Milke

Coal seam gas (CSG) exploration and development requires the abstraction of significant amounts of water. This is so because gas desorbtion in coal seams takes place only after aquifer pressure has been reduced by prolonged pumping of aquifer water. CSG waters have a specific geochemical signature which is a product of their formation process. These waters have high bicarbonate, high sodium, low calcium, low magnesium, and very low sulphate concentrations. Additionally, chloride concentrations may be high depending on the coal depositional environment. This particular signature is not only useful for exploration purposes, but it also highlights potential environmental issues that can arise as a consequence of CSG water disposal. Since 2002 L&M Coal Seam Gas Ltd and CRL Energy Ltd, have been involved in exploration and development of CSG in New Zealand. Anticipating disposal of CSG waters as a key issue in CSG development, they have been assessing CSG water quality along with exploration work. Coal seam gas water samples from an exploration well in Maramarua closely follow the geochemical signature associated with CSG waters. This has helped to identify CSG potential, while at the same time assessing the chemical characteristics and water generation processes in the aquifer. Neutral pH and high alkalinity suggest that these waters could be easily managed once the sodium and chloride concentrations are reduced to acceptable levels.

Jan 1, 2005

Characterisation of Computer Printed Circuit Boards for Hazardous Properties and Beneficiation Studies

Sep 13, 2010