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By Pedro E. Rengifo

Splicing methods have undergone considerable developments over the last 2Oyears. Continuous conveyor belt service is dependent entirely on the strength and life of the splice to hold the two ends together. Ultimately, belting performance is dependent on the quality, efficiency, and technique of the splicer. As customers demand better belting performance and running tensions increase, the need for splices that perform as efficiently as the belting has increased also. Higher dynamic belt constructions have also dictated the need for "new"sp1icing techniques. Regardless of the belt type used or spliced, one item that is most necessary with all belt types is the quality of the workmanship and standardized splicing methods that employ all of the necessary elements required to ensure reliable field service. This paper will explore the use of Goodyear-issued internal standards for field splicing following the constraints of quality and efficiency for fabric and steel cord reinforced belting. Also included are the 10 most common mistakes made by splicers, Goodyear-issued Field Quality Assurance Standards, and check lists for end users to adhere to the manufacturers' requirements for splicing including materials and specifications for conveyor belt splicing and repairs.

Jan 1, 2004

By G. C. Smith

Process control applications in the minerals processing industry have grown extensively over the years due to the many benefits derived, both financially and operation-wise. Although control theory is widely known, conventional control does not address many of the problems posed by minerals processing circuits. Some of these problems include interactions between process units, large dead times, few and sometimes unreliable measurements of process variables, non-linear systems, disturbances entering the process, processes with varying dynamics, and many more. For the past 26 years Mintek has been active in the field of providing specific, customized solutions for the minerals processing industry. This paper focuses specifically on applications in milling and flotation control. The underlying control principles have been applied to a wide range of other processes including submerged arc furnaces. Advanced control application is implemented on a common advanced control platform, called the PlantStar. Much innovation has been brought to the fore in terms of adapting theoretical techniques and developing new methods to resolve specific milling and flotation circuit issues by using process control. The general approach adopted by Mintek when implementing advanced control is to enforce stabilization of the process as a solid foundation for optimization strategies to be built upon. In doing this, a robust control solution is presented, and the end result is flow and level stability, better product quality regulation, increase in throughput and a stable feed to downstream processes. The MillStar advanced milling control system ensures that the milling circuit is at all times easy to operate while achieving optimum product quality and throughput. Stabilization should include product size regulation and sump level control. Another important aspect of stabilization control is the handling of milling circuit constraints without introducing cyclical behaviour and with minimal disturbance to the final product quality. Process constraints may include factors such as process water limitations, cyclone feed density, and cyclone underflow angle. An optimization strategy should be developed to increase the mill throughput without affecting product quality or introducing mill overloads. The relationship between solids feed and power draw is examined and manipulated for optimization. The interactive nature of flotation circuits and the presence of recirculating streams tend to make satisfactory control almost impossible with conventional techniques such as PI (Proportional plus Integral) or PID (Proportional, Integral and Derivative) control. The FloatStar Level Stabilizer simultaneously considers all the flotation levels in a circuit by use of a multivariable algorithm, and takes compensating action in anticipation of disturbances. The FloatStar Flow Optimizer is an optimization strategy that controls the concentrate flow rate between various sections of a flotation circuit (e.g. Rougher ?Cleaner; Cleaner ?Recleaner). By controlling the concentrate flow between the sections, the mass pull, circulating loads and residence times of the circuit can be stabilized, thereby enhancing the performance of the flotation process. Optimizing grade and recovery are coupled with the dynamic optimization of circulating flows. The FloatStar Grade-Recovery Optimizer will maximize the grade in a section, whilst ensuring that recovery or any other process specific limits remain within predefined limits. With successful applications on several milling and flotation plants worldwide processing amongst others PGMs, gold, copper and nickel, Mintek has shown that it is a leader in milling and flotation control innovation

Jan 1, 2004

By Lanre Oshinowo

Computational Fluid Dynamics (CFD) is used in conjunction with process modelling at HATCH to achieve a superior level of confidence in the process design of hydrometallurgical process plants. The use of these tools to evaluate designs through virtual prototyping reduces the risks associated with making design decisions. This paper highlights the development of a co-simulation strategy at Hatch for the seamless integration of process modeling software addressing different scales (process time and space): flowsheet level models and .equipment level models. With co-simulation, the process design engineers can improve design accuracy, troubleshoot and optimize performance and influence decisions impacting equipment operation by representing specific unit operations in the flowsheet model software with detailed CFD models. Specifically, this paper will focus on the co-simulation of a Ni/Co high-pressure acid leach (HPAL) process including heaters/heat exchangers and flash system, autoclave and quench/scrubber system. The knowledge developed can be transferable to other processes.

Jan 1, 2004

The concept of æsustainabilityÆ can largely be defined as development that will not compromise the ælivabilityÆ of the planet for future generations. It has multiple dimensions, such as the triple bottom line û environmental, economic and social. And it also includes temporal (now and the future) and spatial (local and global) aspects that have to be taken into consideration to achieve true sustainability.Energy sustainability might be defined as û having the light turn on when you push the switch. It has, of course many more dimensions than this simplistic definition. Coal in Australia has an important role in keeping our lights on, but has its problems that need to be tackled head on to maintain a role in sustainable development.An overriding issue in terms of sustainability for coal is its major contribution to our greenhouse gas emissions. Whilst we have one of the most effective energy sectors in the developed world, based on well-managed, abundant fossil fuels, our greenhouse gas emissions are one of the highest per GDP in the developed world. We have to reduce our ægreenhouse gas signatureÆ.This paper explores the issues of coal utilisation greenhouse gas emissions as an indicator of the fuelÆs sustainability and the potential lower emissions pathways we will have to follow in a future carbon-constrained world.The technology changes will have significant implications for the minerals industry and it is argued that forward-looking coal/greenhouse emissions strategies need to be developed in alliance with the coal (and energy) sector for the minerals industry to maintain its global competitiveness.

Jan 1, 2004

By L. C. Stilwell

The paper will place into perspective the contribution that platinum makes to the South African economy. It will use statistics from official sources, namely the Department of Minerals and Energy, the Department of Customs and Excise, the South African Reserve Bank and Statistics South Africa. Surprisingly few people are aware of these statistics, especially Supply and Usage tables, published by Statistics South Africa, and trade statistics, published by the Customs and Excise division of the South African Revenue Service. The paper will therefore contain a concise explanation of input-output tables and supply usage tables, as well as the derivation of gross domestic product and an outline of the System of National Accounts, of which Input-Output Tables and supply and usage tables are components. GDP is a commonly used, but poorly understood, measure of the wealth of an economy. The paper will explain the methods used by SSA to calculate this indicator and its place in the System of National Accounts (SNA). South Africa exports almost all its platinum production (87.5% in 2002). Exports are a final demand, as opposed to intermediate demand from secondary industries, and therefore do not enter the value-adding process, which is the essence of GDP. By definition, therefore, platinum on its own is not a major contributor to GDP. The platinum industry does, however, have an impact (known as the multiplier effect) on other sectors of the economy. The paper will explain the meaning and derivation of these multipliers, using a model based on an Inverse Leontief Matrix.

Jan 1, 2004

By B. Stettner, J. Asante, S. Abraham

The levels of nitrogen in steel produced in various metallurgical vessels vary significantly. For example, the tap nitrogen levels in steel produced in the BOF are around 4Oppm, as compared to 70-100ppm in both DC and AC electric arc furnaces. Given the pressing need to reduce nitrogen levels in steel to satisfy customer demand, IPSCO Inc. has gained considerable experience in controlling nitrogen levels in steel over the course of the last three years. Hence, a cost effective process has been developed through an intensive nitrogen control program from steel melting in the EAF through to the continuous slab casting stage. This paper describes the practices employed at each stage of the steelmaking process that have enabled IPSCO Inc. to reduce and control nitrogen levels in steel.

Jan 1, 2004

By J. Farrell

The Canadian government ratified the Kyoto Protocol in December 2002 and, prior to ratification, committed to equitable distribution of the burden of implementation. The Federal government's Large Final Emitters group is working with industry to develop covenants that will consider the unique nature of the company's operations and not unreasonably burden any one sector or company. Ensuring equitable distribution must consider local, national and international issues. From a Canadian iron ore producers perspective, the fact that most of the iron ore production in the world is in countries that have no Kyoto commitment is a critical issue. Another issue unique to this sector is the increased addition of fluxing agents in iron ore pellet production which has shifted some process related greenhouse gas emissions from steel producers to iron ore producers. While the objectives of the Kyoto Protocol are primarily environmental, the economic implications for Canadian industry are not trivial. For decades Canadian companies have been actively improving energy efficiency and reducing greenhouse gas emissions to maintain a global competitive position. Production of iron ore pellets is an energy intensive process and the Iron Ore Company of Canada (IOCC) is the largest Canadian producer. In 2002 IOCC identified energy and Kyoto Protocol implementation as critical risk factors for their organization and appointed a full time Energy Manager. In January 2003, IOCC initiated a comprehensive process for identifying energy cost reduction opportunities and established an Energy Master plan. This process included:

Jan 1, 2004

By J. Budac, R. Krentz, P. Cordingley, G. Freeman, M. E. Chalkley, H. Scheie

Pressure hydrometallurgical unit operations have been in commercial use at the Fort Saskatchewan refinery of Sherritt International Corporation for fifty years. This paper traces the history of Sherritt from its origins in northern Manitoba, and the development of the first hydrometallurgical nickel-cobalt refinery in 1954, utilizing pressure hydrometallurgy, to the modern day refinery. Sherritt's involvement with pressure hydrometallurgy during the past 50 years has included the operation of the refinery, the development and licensing of technology, incorporating pressure hydrometallurgical unit operations, to more than 30 companies worldwide, the joint venture at Moa, Cuba involving both leaching and precipitation at elevated temperature and pressure, and the production of specialty metal powders. Developments in each of these areas are reviewed.

Jan 1, 2004

By J. Walker, G. E. Kim

Since May of 2000, Mogas Industries, in partnership with F.W. Gartner Thermal Spraying Co. and using the services of Perpetual Technologies, has invested time, energy, and resources towards developing novel ball valves for high-pressure acid-leach (HPAL) service. In addition to developing new valve designs, an aggressive coatings development effort has been undertaken to improve the protective quality of the coatings so as to enhance the performance and extend the life of valves in severe HPAL conditions. In 2001, Mogas Industries qualified and applied a nanostructured titanium oxide (n-TiO2) coating for gold and nickel/cobalt HPAL services. The n-TiO2 coating provided dramatically superior protection against abrasive and erosive wear, fared very well against high-pressure autoclave corrosion testing, and has performed well in HPAL service.

Jan 1, 2004

By R. Corriveaau

This paper is about a horizontally curved conveyor, which carries 6,050 stph of limestone over land from a new quarry to the owner's plant. The conveyor is 5,012 ft long with a horizontal curve radius of5,OOOft Site conditions made a curved conveyor design the most optimal and economic solution. Using our unique custom conveyor calculation program, TKRI was able to accurately model and design the conveyor to properly track the belt and prevent any spillage through the horizontal curve radius. A data monitoring system was installed that allows monitoring of the conveyor both locally and remotely. The remote monitoring allows TKRI to contact the owner for preventive maintenance. Preventive maintenance can reduce the conveyor downtime during normal operating hours.

Jan 1, 2004

By A. Yousefpour, M. Hojjati, M. Simard, M. Laramée, M-A. Octeau

The need for effective and reliable joining methods grows as the use of advanced thermoplastic composites becomes widespread in aerospace industry. An experimental investigation of resistance welding of APC-2/AS4 thermoplastic composite laminates is presented. In this method, a heating element is placed between the bond-surfaces then the interface is heated by passing electrical current through the heating element. The polymer at the weld interface is melted due to resistance heating, then diffuses and consolidates under applied pressure, resulting in a weld. APC-2/AS4 prepreg, APC-2/AS4 commingled, and different grades of metal mesh heating elements were considered. A custom made resistance welding rig was designed and developed to perform lap-shear welds. The mechanical performance of the welds was quantified using single lap shear tests. The effects of different heating elements on the mechanical performance of the resistance-welded parts were investigated. Also, quality of the welds was examined under optical microscopy.

Jan 1, 2004

By L. Newman, R. Wyrick, R. Berezowsky

The Stillwater Mining Company operates an integrated mines, mill, smelter and base metals refinery complex in Montana, USA for the production of a high-grade platinum group metals (PGM) bearing concentrate, nickel sulphate crystal and cathode copper from the PGM-containing nickel-copper converter matte. The complex was constructed in stages over several years, starting with the mine and the mill, followed by the smelter and finally, a base metals refinery, which was commissioned in 1996. Due to the relatively small quantity of matte production, a straightforward refinery process was initially selected to extract the base metals, which reported to a mixed nickel-copper solution for further treatment off-site, and yielded a high-grade PGM concentrate suitable for treatment in a PGM refinery elsewhere. Subsequently, as a result of increased matte production, the process was modified to separate the nickel and copper, and to produce a nickel sulphate salt and cathode copper. This paper describes the design and operation of the original and the modified processes utilized in the base metals refinery (BMR).

Jan 1, 2004

By John Hutchings

Drilling and blasting is a clearly delineated work process, which has well defined inputs and outputs. Drilling and blasting is also a process with a number of steps each of which has measurable outcomes. Drilling and blasting is ideally suited to the application of Total Quality Management principles. Most drilling and blasting information is generally poorly managed with disjointed and unrelated Information Technology systems managing parts drilling and blasting data. Data is often moved from on system to another, sometimes manually. In the field, drilling and blasting is still very much a paper based system and which has not generally benefited from some of the recent hardware and software technology advancements now “on the shelf”. Data collected on paper rarely is transcribed back into an electronic system for further analysis. It is often difficult to collate or review historic drilling and blasting data. This paper will present a definition of Total Quality Management and demonstrate how it can be applied to the drilling and blasting work process. Total Quality Management defines the mechanisms for the application of continuous improvement to drilling and blasting. Continuous improvement will provide opportunities to modify drilling and blasting work process outcomes and generate real cost benefits within the overall mining process. A complete drilling and blasting management system frame work, called DBS, is presented in this paper. DBS provides all the components necessary to implement a full drilling and blasting Total Quality Management solution. Also highlighted will be appropriate “off the shelf” technology that can be applied to replace current paper based systems and provide the means to connect with other mine data systems. Various examples will be discussed which will demonstrate potential benefits of applying a structured Total Quality Management approach to a drilling and blasting work process.

Jan 1, 2004

By Finlay Campbell

Nickel laterite pressure acid leach plants and reduction roast plants have had a checkered history in their engineering, construction, startup and operational reliability. Many potential projects have been the subject of detailed studies over the last thirty to forty years but relatively few have advanced to commercial production. Four reduction roast plants are currently operating, an additional one was partially constructed but never completed, and another was started up in 1974 and shut down after 12 years operation. Three acid leach plants have been built and commissioned in the last five years, trying to follow the example of the Moa Nickel plant in Cuba. An additional acid leach plant project is currently on hold, following limited construction work, its future subject to review by the owner because of potential cost over-runs. This paper attempts to discuss difficulties that may be encountered as a project is developed and will address factors which may affect production ramp-up schedule, long term production performance and overall production success. Comparisons are made with ramp-up performance at other large metallurgical plants that employ some comparable unit operations. Keywords: Caron, PAL, nickel laterite ore, ramp-up, reliability, process development, equipment design, step-out, commissioning, startup.

Jan 1, 2004

Multi Torque Industries and Jadefoil have developed a safer, more efficient method of explosive protection, retention, placement, and constraint. In particular, this refers to advancements in airbag technology, where the system will offer an alternative to conventional gasbags and decking methods to provide a far more controlled and safer working environment. Airbags have provided operator control and reliability which has not until now been possible in this type of application. The benefits have been noted by current users and the advantages have provided an increase in productivity and significant savings in explosive waste. Obvious problems with gasbags lie in their instability in hot conditions where the danger is associated with gas canisters exploding with great force posing a significant risk to operators. Other problems associated with the decking systems currently on offer is the lack of versatility and operator control. The airbag systems give the operator full control to guarantee accurate placement, assured retention whilst boasting a quick operation of less than a few seconds for conventional void blocking, decking and plugging. One of the main advantages of the airbags is that the operator has full control over placement and retention force, therefore in wetter conditions where slippage can be a problem extra air can be added at the operatorÆs discretion to ensure a sufficient grip. Technical calculations coupled with experimental testing have demonstrated that an airbag will support the weight of a 30 m water column in an 89 mm hole at an initial bag pressure of 5 psig. Applications are increasingly growing whilst more customers embrace their use. Advancements such as the ability to deck in overhead holes, block voids in overhead holes at any depth, explosive retention in very wet conditions, longhole stabilisers to prevent hole closure and concertinaed liners reflect a dynamic potential for new technologies. All of these applications provide a decrease in explosive waste, an increase in operator safety, an increase in explosive protection, and an increase in productivity.

Jan 1, 2004

By D-J Min

Strategies and achievements in the Asian steel industry to construct industrial ecological chain are reviewed largely in the case of Japan, Korea and China. Emphasis is placed on the development of resource circulatory system for the minimisation of various wastes and emissions of green house gases (GHG), toxic gases and polluting particulates. The minimisation includes:Rationalisation of iron and steelmaking processes; Implementation of available relevant measures/technologies; Life cycle assessment in designing steel from semis to assembled products; Reduction, reuse and recycling of materials and energies; and Utilisation of core competence technologies to process domestic and industrial wastes. In view of global nature of the above wastes- and emission-issues, inter-industrial linkage and international cooperation across the borders in the Asian countries have become more important. Inter-industrial linkage definitely serves to cut back the wastes and emissions. Examples of such linkage and factors influencing the sustainability of the linkage are described with expectation for further development of the linkage. Importance of international cooperation cannot be overstressed under the circumstances where steel production in China exceeded 220 Mt and world production exceeded 945 Mt in 2003 and is still increasing. Practical measures are discussed to enhance the linkage and cooperation for effectively promoting the reduction, reuse and recycling, including implications for the nonferrous industry.

Jan 1, 2004

The mining industry has expanded significantly in the Pacific Region over the past two decades through a mix of new developments and brownfields expansions of existing operations. Despite this overall success there are also a number of well publicised examples of less than successful minerals ventures. These problem developments highlight the fact that success cannot be taken for granted and that rigorous planning and attention to detail is essential. The dominant growth has come through expansion of existing businesses, notably alumina, iron ore and coal, achieved through both efficiency gains on existing plant and step change capacity additions such as new mines and/or expanded processing plant. This expansion has largely been linked to increased market opportunities. The major issues are the quality and extent of the host resource, achieving the market targets, and the efficiency of the expansion effort. There can be also a range of site specific issues which need to be addressed. The development of new greenfields operations is often more complex as it can bring a wide range of new issues. Depending on the nature of the development, and the companies involved, these can extend from initial financing through to obtaining a market position. Incorporating major new technology and/or establishing infrastructure and attracting staff to remote locations can also add significant challenges. This paper outlines many of the critical factors which need to be considered prior to proceeding with major expansions or greenfields developments. These will be linked to a number of developments in the region over the past decade.

Jan 1, 2004

The original and most basic relationship between mining company and explosive supplier was a simple one of consumer and product supplier. The divide between the two was quite clear-cut with neither taking much interest in the activities of the other. The explosive supplier had little understanding or share in the outcome, efficient rock breakage and therefore impact on mining and milling. Likewise, the mining company did not encourage the improvement or development of products. The transactions were limited to product and funds. This environment does not encourage any form of knowledge sharing, trust or optimisation of the mining process.Conversely, there are now a variety of relationships to the point that the mining company may simply be an asset manager whereby all æoperationalÆ aspects are contracted out. For the drill and blast aspect this takes the form of a æRock-On-GroundÆ contract whereby the explosives company takes on design, drill, load and fire responsibilities and is paid a rate per volume of broken rock. This removes the majority of risk to the mining company derived from having to produce broken rock and guarantees the cost of a portion of the overall unit cost of mining. The onus is now on the explosives supplier to break rock to a specification as efficiently as possible.There exist a number of variations between the æbasic supplyÆ and æRock-On-GroundÆ. These contracts may also include value sharing to encourage the explosive supplier to optimise the mining operation to maximise profit.This paper looks at some of the drivers for the change in explosive supplierûconsumer relationships and examines the æprosÆ and æconsÆ of a few of the options.

Jan 1, 2004

By A. M. Hearn, J. G. Roos

Energy consumption, being a large proportion of the input of the ferroalloy production process, can be measured in terms of the efficiency with which the energy is utilized and the effectiveness with which it is used. The efficiency of the usage of energy revolves around the specific consumption of the energy for the production of the alloy, which encompasses the thermodynamic aspects of the process and is more of a metallurgical function that will not be addressed further in this paper. The effectiveness with which the energy is utilized is determined by the optimisation of the electricity supply from the utility (in this case Eskom). The South African electricity supply industry is on the brink of considerable restructuring, implying changes in ownership, structure and regulation. In other countries, however, restructuring has often seen higher prices. Owing to the diversity of growth prospects in South African markets, Eskom is turning to new market management and generation strategies. In future, Eskom will develop pricing strategies to increase demand from attractive customer segments such as paper & pulp, iron & steel, aluminium, and other metallurgical industries. There will be a broader spectrum of product offerings, including dynamic pricing options and demand-side management incentives. In a future electricity market that will become more dynamic and demanding, it will become increasingly important for electricity consumers to optimise their electricity supply. There are many facets in optimising the electricity supply, which include optimal utilisation of the tariff, integrating energy cost management into the production planning process, implementation of demand-side management actions, modelling, scenario planning (.what-ifs?.), optimisation, maintenance scheduling coordinated with the tariff periods, etc. This paper gives consideration to the status of the development of technology at the manganese alloy works of Samancor at Meyerton, South Africa in order to increase the effectiveness with which energy is utilized.

Jan 1, 2004

By A. More, J. Bullón

Metal casting is one of the most important operations in ferroalloys factories. After the tapping of the furnace and the depuration of the metal, the preparation for customers with cooling, crushing and sizing begins. In total production costs, this contains around 8 % of the total cost of the metal, depending on the value of the fines and other important parameters. From an investment point of view, this represents around 20% of the total capital for a new furnace. Casting onto a water-refrigerated copper plate is not new for molten metals. In steel, continuous casting machines are normal in every factory. Water granulation casting exists at some ferroalloys plants. However, the majority of plants and production technology still use the technology of lumping, crushing and sizing. This technology is time consuming, produces fines and requires a relatively large work force. In 2001, Ferroatlantica put into operation a new water-cooled copper casting-machine, which seems to be a very convenient solution to solve all these problems. It is in operation at a silicon factory; the same place where the new ELSA electrode was developed for silicon metal production. This paper describes our experiences using it.

Jan 1, 2004