Search Documents

By A. N. Aposhian

The electronics industry generates tin/lead bearing by-products that can be recycled for their metal value. This paper will cover the processes used to recycle these tin/lead bearing byproducts from the plating, circuit-board fabrication and assembly industries. Though these processes are well known to the companies who do the recycling, few outside the industry including the generators of the by-products, understand the processes or needs of the industry. This paper will give a broad overview of these processes, and describe the services provided by this industry. The paper will also touch upon the future of the recycling industry, including the legislative and environmental push for the elimination of lead from electronics.

Jan 1, 2000

By D. Kennis

"Union Miniere Precious Metal's (UMPM's) Hoboken Business Unit has a long tradition in complex Pb-Cu metallurgy, focussing on the recovery of precious metals from various types of secondary and recyclable materials. Although the old flow sheet, based on a traditional sinter plant, blast furnace, and lead refinery process was a very complete flow-sheet with the capability of dealing with almost every impurity, the weaknesses became clear:1. old and costly technology,2. too many unit operations,3. too much internal recycling, and4. dependency on concentrates for the sintering process.To maintain the competitiveness of the Hoboken Business Unit, the project ""Smelter 2000"" was born. This project represents a breakthrough in metallurgical processes and technology. A modem smelting technology was chosen together with the development of a new process. A lead-copper process combining lead slag and blister copper production, carried out in an ISASMEL T vessel, was the key to simplifying the Hoboken flowsheet. ISASMEL T smelting technology was chosen for its flexibility towards feed characteristics and process parameters.The new smelter was commissioned at the end of 1997. Although there were a lot of problems due to the high degree of technical innovations in the process, the new smelter came to design capacity within 1 year after start-up. During this period, however, UMPM had, a very difficult time because of the extreme clear-cut nature of going from the old to the new flowsheet.After two and a half years of operation, the new flowsheet has proven to fit with the strategy of UMPM, focussing on treating secondary Pb-Cu materials and a broad range of recyclable feeds such as electronic scrap (E-scrap) and catalysts. Together with the new Precious Metals Plant, efficient logistics, recognised world class sampling practices and a customer-focussed commercial organisation, UMPM Hoboken can definitely be considered reborn."

Jan 1, 2000

The extraction of world-class mineral deposits using massive underground mining techniques is not an entirely new theme to world mining companies and experts. Previous MassMin conferences have helped to gather and disseminate the valuable experience and knowledge so important for the proliferation of safe and efficient mining of large underground deposits. With the passing years since the first MassMin conference in Denver in 1981, a number of factors have contributed to an increase in massive underground mining around the world, including environmental pressures, gradual exhaustion of shallower deposits and the enabling effects of improving technology in disciplines related to underground mining. Massive underground mining is heading deeper, embracing challenges which include working with elevated temperatures, increasing in situ and mining induced stress levels and longer ore transport routes. Improvements in mineral processing technology will tend to lead operators to contemplate the extraction of lower grade orebodies in the event that the ore can be efficiently transported to the surface and hence the plant. No doubt this tendency, and its associated challenges is encouraging a rich growth in innovative engineering in such fields as mine planning and materials handling as well as geomechanical issues such as support design and the simulation of extraction sequence effects on stress re-distribution. MassMin 2000, we are sure, will showcase a wide variety of new contributions in thought and actions in these fields. There is a definite place for academic institutions and mining related suppliers in the process of developing new technologies and practices in support of present and future endeavour in this field. Dyno Nobel has its own part to play, certainly as an enthusiastic and proud major sponsor of MassMin 2000, but also by means of identifying common cause between our Vision and Values and the needs, present and future, of the underground massive mining industry. The critical success factors, which Dyno Nobel pursues are:health, safety and environment, customer relationships and market development, cost optimisation (while maintaining quality), technology and innovation, organisational development, and leveraging capabilities globally. Through the present paper we would like to share some of these values and offer some practical insights as to how their realisation will contribute to the achievement of MassMin goals and needs.

Jan 1, 2000

Zircon producers are often required to lower impurity levels to meet customer specifications as most of these impurities adversely effect the end use. For example, zircon sand in foundry applications needs to be free of any surface impurities (eg clay, gibbsite and goethite) which otherwise could cause sintering or fusion between cast metal and the zircon mould. Light coloured ceramic grade zircon, typically low in iron oxides and titania, is preferred in ceramics applications. The presence of impurities in zircon sands is a problem in the magnetic and electrostatic separation stages of their concentration. Previous work (Aral et al, 1997) showed that impurities in zircon sand concentrates occurred in the form of stains on grain surfaces, discrete gangue minerals and in the mineral grains. The gangue minerals such as rutile, garnet, xenotime, monazite, spinels, ilmenite, and aluminium silicates in the concentrate in some cases (Aral et al, 1997) contribute significantly to the impurity content of the concentrate. A careful hand picking of the impurity grains from a Western Australian zircon sand showed that the impurity content of the concentrate could be lowered significantly as a result of the removal of the surface stained grains and gangue minerals. The hand-picked ædirtyÆ fraction, comprised about eight per cent by weight of the concentrate, and consisted mostly of iron-oxide/hydroxide-stained zircon, silica grains and rutile, and occasionally ilmenite, monazite, gahnite and other (unidentified) coloured grains. The chemical analysis of the remaining æcleanÆ fraction showed that the major impurities (Fe and Ti) were reduced significantly (Table 1). The reduction in the uranium content was about 30 per cent. The other measured impurities, P, Mg, Al, Th, and Ca remained mostly unchanged as shown in Table 1. The contribution of ilmenite to the overall iron content of æcleanÆ zircon was insignificant as it comprised about 0.1 per cent weight of the æcleanÆ zircon. Rutile was the major source of titanium contamination (about one per cent by weight). Recent work (Aral and Calle, 1999) on zircon sand concentrates from the Murray Basin showed that, under the electron microprobe, the bulk of the impurities occurred in the dark back scattered electron (BSE) regions of the zoned zircon grains. The impurity contents of the light BSE regions and unblemished (unzoned) grains were low. The impurity content in zoned zircons has been investigated on single, relatively large, crystals (McLaren, Gerald and Williams, 1994; Smith et al, 1991; Romans, Brown and White, 1975). These studies generally aimed to investigate the incorporation of U in zircon as zircon is used extensively for U-Pb geochronology owing to its relatively high content of uranium. Smith et al (1991) identified a striking difference in composition between the areas of lower (dark BSE) and higher (light BSE) average atomic number in the zoned zircon. Their work showed in particular that the zones of lower atomic numbers contained very significant amounts of trace metals such as Y, REE, Nb, U, Al, Fe, Ca, Ba and, by difference H2O. In this paper the impurity distribution in zoned zircon grains was investigated on statistically significant number of grains before and after a leach treatment. The distribution of impurities was also measured in unblemished areas to compare the results.

Jan 1, 2000

By Kiyoshi Shibata, Jun-ichi Hayashi

"Steel making technology poses strong potentials for environmental protection in three direction. One is pollution control on steel making process itself. Japanese steel industry has cut down various type of emission drastically since 1970's. Secondary, those process technology can be applied to reduce environmental burden in other industrial sectors. One of the successful examples is municipal waste treatment facility. Thirdly, development of high performance steel products, such as high strength steel for automobile body, can contribute to improve environmental performance during their use, based on the concept of life cycle assessment. Some examples of the successful development and future task is discussed.IntroductionsStack and smoke used to be a symbol of energy intensive industry such as steel making. But, scenery of steel works and its surroundings have been completely changed, and steel products have been changing, as well. The steel making industry consumes huge quantities of energy and resources. Variety of technical development have been carried out to reduce the pollutant release. The steel industry in Japan has been making direct and indirect contributions to reducing of various kinds of environmental impacts through development of high-performance process and products: Its potential technical capability accumulated in steel making is fundamental and essential infrastructure for the vein systems of our society. In this paper, the activity of steel making industry for better environment is discussed"

Jan 1, 2000

By A. Sullivan

Success in mining demands the creative application of equipment, systems and processes to the unique needs of each mineral deposit, market and, though often overlooked, the culture of the individual business. In recent years, domestic coal mining companies have become more attentive to the contribution safety and loss control programs have on their financial results. Although most have adopted fairly conventional safety programs, some have created systems and processes tailored to their unique circumstances. While each coal mining business must consider the typical risks inherent to our industry, excellence in safety is most likely achieved when a safety program is customized to meet the needs of the individual business.

Jan 1, 2000

There is growing acknowledgement that successful organisations, including mining companies, achieve their competitive advantage by better managing their employees, customers and other stakeholders. The fact that I have been asked to address this conference is perhaps evidence of the recognition of the importance of ensuring the improved management capabilities of the personnel within Australian mining companies. As many of you will be aware, prior to my appointment to the role of President of Minera Alumbrera Limited (MAA), the operator of the Bajo de la Alumbrera project, my career had been more generally focussed on industrial relations and human resources management. My appointment was met by surprise in some quarters, as it is unusual for a person without the technical background of a mining discipline to manage a world-class mining operation. However, it was recognised early in the life of the Alumbrera project that the operation did not lack technical expertise or a committed workforce; rather what was required was innovative management of the project and its operational resources, particularly given that we were operating with totally ægreenÆ workforce in a country without a large-scale mining culture. It is my experience that a particular shortcoming of mining companies is that they have tended to ægrowÆ managers based on their technical expertise rather than people management skills. Historically, many companies have assumed, or at least hoped, that their better technical people would develop the requisite skills to take on the challenges of management. Such philosophy has not always met with success. Whilst the topic for my presentation was originally published as People in the Mining Industry, within the context of the overall theme for this plenary session, People: Education for the Future, it is a subject with an extraordinary breadth of possibilities for discussion. Therefore, I have chosen to redefine my presentation to People Management Issues in Offshore Mining Projects,an issue which I consider to be an important area within the overall topic and one which has particular currency given the increased tendency by Australian miners towards offshore exploration. It is also relevant from the perspective of continued rationalisation of our industry, the recognition that there will be more large-scale, global corporate mining entities and that significantly more mining professionals will become æcitizens of the worldÆ. We therefore need to prepare our future leaders for these challenges. The topic also allows me to highlight the importance of an holistic management approach as the establishment of a new project in a foreign environment puts into stark relief the need for the application of the full range of competencies, rather than the narrow ætechnicalÆ approach to doing business. I hasten to add, however, that the mining industry is not alone in this regard and I was interested to read an article in the Weekend Australian of 22/23 January 2000, which reported on the first key speech of former Westpac CEO, Bob Joss, as Dean of the Stanford University Graduate School of Business. He said: à We know that when our students go out into the world, if they have to struggle, it will not be because theyÆre not smart enough, or they donÆt have enough good ideas. It will be because they struggle over managing themselves and their relationships to other people. The article then went on to say that Bob Joss foreshadowed an initiative to build alliances between the Business School and other Humanities departments within Stanford University to draw on their learning. Other business schools have also recognised this need, albeit somewhat late in the day, as have the most enlightened of modern corporations; in summary, successful businesses have recognised that in an age where competitive advantage through, for example, technological breakthroughs is very short-lived, it is the quality of management that will provide the leading edge. By using the Alumbrera project as a case study, I will identify certain of the challenges with which companies and individuals may be confronted in the establishment of a greenfields project outside Australia. However, many of the issues raised will have direct application in the context of the development of an Australian operation. My objective is to provide an indication of areas which should be considered at the formative stages of a projectÆs development, with particular focus on the issues of people management. I would expect that such a study would be of benefit to companies, education institutions and individuals in preparing themselves for similar experiences.

Jan 1, 2000

It is easy to demonstrate the importance of aggregates in any conversation about infrastructure and other engineering artefacts. Peoples around the world have made use of stone to enrich and enhance their lives since the earliest days of civilisation. In New Zealand, Maori used hard durable rocks for weapons, tools, and basic structures. European settlement accelerated the use of quarried materials and formed the basis for development of our society as we see it today. Logic might suggest that the quarrying sector would be recognised positively for, and encouraged to continue to contribute to, this underpinning of the way we are. The reality is æNot In Most Back YardsÆ. Why? The rock is where it's always been (often overlooked) and our æsocialÆ environment is today's hard place. For a resource-based business in New Zealand, that environment is principally the Resource Management Act, with the widespread power it has distributed to anyone prepared to invest their time. This coupled with a lack of leadership and direction in the implementation of the Act has created a climate that stifles development and diverts energy and resources to æplaying the gameÆ rather than ælifting the gameÆ. Perhaps the real costs of this are not yet widely recognised. The paper will draw mainly on the experience of endeavouring to consent a ægreenfieldÆ quarry in the Waikato region. This is supported by commentary based on nearly 10 years of ælivingÆ with the RMA at sites across much of New Zealand. RMA Scorecard Summary: Effects based? Rarely. Level playing field? No. Maori Consultation? Could do better. Efficient use of resources? No. Timely? No. Is it working for other sectors? Certainly not the quarrying industry's customers and end users.

Jan 1, 2000

By Ron Lutz

In today’s world, production is the name of the game. We are all in business to make money. In the Quarrying and Mining industry the same holds true. The primary goal is to develop the best drilling and blasting program available to maintain uniform fragmentation to maximize production. Also we want to maintain drilling and blasting costs and minimize escalators. This paper is intended to discuss ways for all parties (quarry’s, blast service and drill companies) to attain this through understanding what can be done to help blasthole drilling and production. Blast designs and seminar’s emphasize the accuracy of drilling to produce better fragmentation. Blast design must also include basic concepts in the drilling process. The type of drill to be used for example whether it is a crawler or truck mount, top hammer or down the hole is important. Quarry operators have a role to play as well. They hold the key to the production of drilling. What the customer does or does not do has a direct effect financially to the drilling. The phrase of pay me now or pay me latter comes to mind. This paper will explore the detail of planning that is required by the quarry and/or blast service companies before a single hole is drilled. The drill must be able to meet the production need of the operation. The type of drill available and what can and cannot be done. The drill cost must be competitive. This paper will touch on comparison drill costs from 1967 to 1999.

Jan 1, 2000

"Canada Centre for Mineral and Energy Technology (CANMET)Natural Resources CanadaMining and Mineral Sciences LaboratoriesA. Address and Contact Information555 Booth StreetOttawa, Ontario, Canada, KIA OGlWebsite: http://www.nrcan.gc.ca/Contact: Philippe Dauphin, Manager, Business DevelopmentTel.: (613) 947-0798Fax: (613) 947-0984E-mail: pdauphin@NRCan.gc.caB. Type and Size of FacilityScope of facilitiesCrushing from minus 4 in. to 10 mesh; grinding - rod, ball, vibration, SAG and impact mills; classification- screening, cycloning, mechanical, hydraulic and dry centrifugal classifiers; froth flotation - automated, column, and frothless flotation; gravity separation- wet and dry; magnetic separation - high gradient, high and low intensity, wet and dry; electrostatic separation; heavy-media separation; calcining; cyanidation; thickening; filtration; drying - fluid bed and freeze drying; pelletizing; microwave.SpecialtiesMineral beneficiation research and development; flotation of sulphides - flowsheet improvement, selectivity, reagent selection; novel flotation techniques; analysis of thiosalts formation; use of mineral processing techniques for recycling.Specialized equipmentHigh gradient magnetic separation, Denver XRF on-stream analyzer, automated flotation cell.Complementary support servicesElectron microprobe; SEM; STEM; X-ray diffraction; particle size analyzer; mineralogical and analytical chemistry services; physical chemistry; hydrometallurgy; pyrometallurgy; engineering and economic evaluation; mechanical shops; technical information services and library integrated with the National Library System of the National Research Council."

Jan 1, 2000

By M. Goto, T., Matsutani, T. Igarashi

"PT. Smelting was established in February 1996 as a company to· construct the first copper Smelter and Refinery in Indonesia with US$500 million direct construction cost and operate it. The plant is located in Gresik, East Java, Indonesia and 20km northwest from Surabaya, 2nd largest city in Indonesia. The site was selected due to following .advantages.1. Adjacent PT: Petrokimia Gresik, - a fertilizer company, purchases all sulfuric acid produced through pipeline.2. Facing on the seashore of the Madura Strait, it is possible to unload copper concentrate from West Papua (3,000km from Gresik) and load granulated slag to the market.3. Close to the good harbor facilities at Surabaya for export the products.4. Gresik Industrial Area has adequate infrastructure.5. Surabaya is a quite nice city to live for people from abroad.The shareholder of PT. Smelting are Mitsubishi Materials Corporation (60.5%), PT. Freeport Indonesia (25:0%), Mitsubishi Corporation (9.5%) and Nippon Mining and Metals Co. Ltd. (4.5%).The Gresik Copper Smelter and Refinery is designed to produce 200,000 tpy of copper cathode from 660,000 tpy of copper concentrates supplied 100% by 'Grasberg Mine of PT. Freeport, Indonesia in West Papua (former Irian Jaya). Other by products are 600,000 tpy of sulfuric acid, 30,000 tpy of gypsum, 509 tpy of precious metal slime and 400,000 tpy of granulated slag. These are sold to domestic and international markets.This project adopted the Mitsubishi Continuous Copper Smelting and Converting Process in the Smelter for anode casting, Contilanod process comprising Hazelett twin belt caster and a Mannesmann's travelling shear were selected. ISA stainless steel cathode process is applied in refinery. The combination of contilanod anode and stainless steel cathode ensured good cathode quality from the very beginning of start-up SO2 gas generated from Smelter is treated by Lurgi-Mitsubishi double contact/absorption acid plant. All contact. wastewater from the plant is treated in multistage wastewater treatment plant.Electricity and oxygen are ·supplied ""over the fence"" by a company which is located in the site of the Gresik Smelter and Refinery."

Jan 1, 2000

By Christoph Beckermann, Kai Liu, Richard A. Hardin

"A two-dimensional heat transfer model for transient simulation and control of a continuous steel slab caster is described. Slab thermal and solidification conditions are computed by the model as a function of time-varying casting speed, secondary spray cooling water flow rates and temperature, slab thickness, steel chemistry, and pouring and ambient temperatures. A solidification model that includes the effects of steel chemistry, cooling rate and mierosegregation on the solidification path is incorporated directly into the caster model. Comparisons between measured and predicted liquidus and solidus temperatures are given for two low alloy steels, and show good agreement. Predicted and measured slab surface temperatures recorded on an operating caster are compared with this transient model and show that the model can predict the temperature response at the slab surface. Results of several simulations are given to demonstrate the effects of changing casting conditions on the slab thermal profile and the solidification end-point. A control methodology suitable for online control of a continuous casting machine is described, and its ability to control the surface temperature profile by dynamically adjusting secondary spray cooling flow rates is demonstrated using the simulator. IntroductionIn order to remain competitive in today's world-wide market for continuously cast steel products, steel producers are finding that it is ever more important to implement process control and to develop a more thorough technological understanding of their casting process. By integrating process control and monitoring into both production and quality control, producers are better able to meet customers' demands for steel of the required quality, quantity, size, grade, and properties at the lowest cost. Computer models used for real-time/on-line prediction and control of continuous steel casters are fundamental tools to accomplish this. Accurate on-line prediction and control of steel solidification and heat transfer allows for more flexibility in caster operation by giving operators the ability to change casting speeds while keeping critical process parameters within required ranges. Such control 'capability also results in more uniform quality throughout an entire casting sequence from startup to shutdown. Furthermore, due to the unreliability of temperature sensors, and the lack of good sensors for important process parameters such as solidification end-point and liquid pool depth, computer-based control models are often the only available option."

Jan 1, 2000

By F. L. Meng, C. S. Henkel, R. M. Alchalabi

For secondary aluminum producers to maintain a profitable melting operation, five technical factors have to be taken into account from the initial furnace building decision to the final operation and production. These factors are furnace design, furnace equipment selection, furnace control, furnace charge selection and inventory, and furnace operation. Any of these five factors, if not chosen or performed wisely, will likely result in sub-optimal melting operation. As a result the MeltSim melting optimization package has been developed by the collaborative effort of Chinook Sciences and AMCS Corporation to take into account these five factors. The package is a mixture of hardware, software, science and experience. The package incorporates years of reverb furnace operational observations, start-up installations, furnace operator experience and furnace physiochemical mathematical model development. The optimization package enables aluminum producers to design new furnaces, select and place proper equipment, optimize existing furnace operations, and convert air-fuel installations to oxy-fuel. The package provides furnace operation monitoring and advisory signals, and furnace automatic optimal control to furnace operators, shift supervisors and plant managers, all customized, based on plant and melter need and ease of information management.

Jan 1, 2000

By R A. Medower

This paper provides a glimpse into the future of minerals processing with emphasis on æAutomation InnovationsÆ for the new millennium, particularly those involving advanced process control and innovative new applications of process control technology in 2007.

Jan 1, 2000

By D. R. Parker

"This paper canvasses emerging trends in public policy and law, which may influence the zinc industry's interest in recycling. There are forces at work beyond direct economic benefits that will drive recycling of zinc, including:• corporate determination to pursue sustainable practices and product stewardship.• public perceptions and pressure,• customer and investor demand,• workforce recruitment, and• protection and expansion of marketsIn this paper, these ""indirect"" forces are examined with particular focus on the zinc industry: It is concluded that, in today's world with an emerging precautionary approach to policy and law making, public perception concerning the environmental implications of metal products, and the need to conserve resources for future generation, a strong industry response is required."

Jan 1, 2000

The role of the mine geologist in a business perspective is self-evident to some, but to others it may be a new concept. All mine geologists need to know exactly how they add value to the business if they are to be successful. Alternatively, if they do not add value, then they will become redundant. This paper seeks to understand some of the contributing problems that hinder the mine geologist from operating in a business perspective. In doing so, a new context (for some) is proposed to aid the mine geologist and the operation gain greater value from geology. The proposal suggests how to ensure that the activities of our geologists are intrinsically linked to the business process that we are involved in. The mine geologist can and must play a pivotal role in the success of an operation. To do this, they must understand some principles of business such as:process, customer/supplier relationships, and organisational structure. Our geologists must know the business objectives, understand the product that the customer needs and use their geological skills to deliver the product safely, on time and to specification. As geologists, we can be instrumental in ensuring that the operational environment is structured in such a way that maximum value is realised, not only from the mine geologists but the entire site team. In doing so, mine geologists will realise their full potential in delivering the outcomes the business demand, and therefore be recognised as strong contributors to business success.

Jan 1, 2000

Block caving is the lowest cost underground mining method but it has relatively high risks and a high up-front capital and development cost. It has application to large, often lower-grade orebodies where high production rates can provide good returns on the investment. However, it has a range of technical risks that are peculiar to block caving and the usual financial, political and environmental risks that may be exacerbated by the long lead-in times associated with the development of a block cave operation. With initial development costs that may be $100 M to $1000 M when the building of a treatment plant is also required, it is obviously important to minimise and manage the risks. In a greenfield project, commitment to a substantial proportion of the capital expenditure may be required to gain access to the deposit, and the decision to proceed at this stage would be based very largely on interpretations of drill hole data. In established mines the data may be supplemented by geological mapping and past experience, etc. The quality of this data is critical and yet it is frequently degraded through poor techniques and avoidable omissions. The final decision to proceed would be assessed on projected commodity prices, mining capital and operating costs, dilution and run of mine ore grades. The latter will vary over the life of the project and these can be estimated with drawdown or draw control modelling techniques. In this modelling, there are further risks in the assumed modelling parameters or that the modelling technique may not be applicable or appropriate. The paper addresses the most critical technical and operational risk areas and provides some practical precautions that can be taken to reduce these and improve the reliability of the geological and geotechnical models.

Jan 1, 2000

By B. Garcia-Egocheaga, J. Rutten, N. Goicoechea, U. Meurer, Mager K., W. Saage, Simonettim F.

Because of the increasing use of zinc as an active and passive anticorrosion agent for steel, leading to constantly growing return rates of galvanized steel components, especially through the automotive industry, major Electric Arc Furnace (EAF) flue dust amounts with higher zinc contents will accumulate in future. Landfilling of steel plant flue dusts is no longer allowable for ecological reasons. These dusts are classified as hazardous by law. Waelz technology is safe and reliable. The range .of treatable feed materials has been extended by process modifications and state-of-the-art offgas technology. Waelz oxide, the product, is delivered to metal smelters for zinc production and the byproduct, Waelz slag, can be used in road construction. Despite the fact that Waelz technology is among the best available techniques (BAT), it is continuously being optimized further with respect to energy input, product and offgas quality in order to comply with the ever more stringent environmental regulations. However, if these flue-dusts are treated, the loops between the steel and the zinc industry can be closed by reusing recovered zinc which in tum leads to savings in natural resources and a more reasonable use of landfills.

Jan 1, 2000

By A. T. Jakubick, A. MacG. Robertson

This paper reviews key issues related to the placement of dry (soil) covers on extremely weak, compressible fine tailings. The design and construction of soil covers on such tailings often presents a formidable challenge to the geotechnical as well as the environmental engineer due to the low shear strength, poor traffic ability, and high settlement of under consolidated tailings at the time of reclamation. The geotechnical issues to be considered include: (1) consolidation of near-surface tailings to achieve strength gains, improve traffic ability, and allow safe placement of initial cover layer; (2) stability of tailings slopes during dewatering of tailings ponds and/or cover placement; and (3) long-term settlement of tailings and its impact on cover integrity and final surface shaping. The environmental issues to be considered include: (1) management of contaminated (free) pond water; (2) management of contaminated pore water expelled during tailings consolidation; and (3) management of (uncontaminated) surface water on top of the cover. This paper summarizes recent experiences gained in a large uranium tailings reclamation project. It is concluded that a careful consideration of both geotechnical and environmental issues during the planning stages greatly reduces the costs and environmental risks associated with fine tailings reclamation.

Jan 1, 2000

By Frank Barker

Mining operations present a very different environment to the suppliers of explosives, initiating systems and services, both on surface and underground. Typical hazards include underground movement, air quality, ground stability, moving equipment, and the use of explosives. As contractors to the mining industry we do not have management control over the environment in which our people operate. The hazards and consequent level of risk that our people are exposed to in some mining operations are significantly higher by orders of magnitude than in a normal factory environment. Orica Explosives (and other Explosives suppliers) are continually and increasingly identifying opportunities to partner with customers by adding value through the provision of services leading to a reduction in total mining costs. These services include the provision of a bulk underground loading services, delivery of product into underground magazines, magazine management, value added blasting, conversions, rock-on-ground contracts, and blast management programs.

Jan 1, 2000