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By Mishra BK, Agrawala S

The traditional method of scale-up uses the population-balance model. In particular, the selection function values for a material are determined in a laboratory mill and a variety of correlations are used to scale these values to plant scale mills. For example, the factor D2-5L (D-mill diameter, L-mill length) appears in many power correlations. The number of collisions is proportional to the number of balls (aD2L), the frequency of mill rotation ((x 1/4D-) and effectiveness of impact ((XD), which gives rise to the 'D2.5L' expression. However, what is lacking in this expression is that it does not throw light on the intensities of collisions. In other words, the collision intensities in both laboratory and plant scale mills are implied to be identical. This fact has been very limiting. Alternatively, the collision frequencies and intensity of impacts can be computed with the discrete element code. This code computes the motion and collision of each individual ball in the ball charge. Therefore the number of collisions and the fraction of collisions in the energy range Et, E2.òòE. (collision energy density) are calculated for a given mill size and operating conditions. Then, using the breakage function determined in drop-weight experiments, the evolution of size distribution is computed for a lab mill. The collision frequency and energy density for larger mill sizes are shown. The fundamental theory outlined for the calculation of size distribution is equally applicable for the large mill, which is the basis for scale-up.

Jan 1, 1993

Discounted cash flow (DCF) methods are well suited and recommended as a primary valuation method for mineral assets for which there are at least indicated resources and some form of feasibility study containing engineering, production and capital and operating cost data. DCF methods are also applicable as a secondary or check valuation method for exploration properties for which no technical study has been prepared. For projects where little or no engineering, production and/or cost data is available, the process of formulating a project concept by specialists who do not possess experience and expertise in the relevant technical faculties is totally rejected as a basis for applying DCF techniques as a primary valuation method. Such an approach runs counter to The Australasian Institute of Mining and Metallurgy (AusIMM) requirement to apply relevant expertise to specific aspects of mineral valuation. Technical and commercial inputs to mineral valuation should be reviewed by specialists who have specific expertise in the relevant disciplines, and should be tempered by the quantity and quality of technical evaluation which has been undertaken and the development status of the asset.

Jan 1, 1994

Concrete has been used for many years in block caving, principally for drift and drawpoint linings. This paper describes the requirements for concrete in this application, the required properties, the mix design, and transportation and placement systems. In addition a concrete mix design rationale is also proposed.

Jan 1, 2000

By M Roche, W J. Huxley

Finding a balance between practical and acceptable groundwater management, and providing for the needs and impacts of mining developments remains a challenge. The changes that accompanied the recent implementation of water reforms have provided greater flexibility for the water manager and greater certainty for the resource user. However uncertainty associated with understanding of complex aquifer systems, balanced against providing for the needs of mining developments, the rights of existing water resource users and expectations of the broader community have not diminished the conflicting issues faced by water resource managers and resource developers. Licensing under the Water Act 2000 provides the regulatory link with the taking of water for water supply purposes or as a consequence of the mining activity. This paper outlines key elements of sustainable water resource management involving certainty of access to water and adaptive environmental management that are delivered through conditioning the water licences issued for the particular mining development. Implementation of this approach is illustrated through a case study involving the BHP Billiton Cannington Mine in North West Queensland.

Jan 1, 2003

By A C. Robertson

Over the past decade there has been continual change in the way that mines have been managed and the component roles of those people who make up the total mine management system. Major issues have included the change in the business structure of mining companies, the change in on-site infrastructure, increased personal liability of managers for the safety and health of employees and increasing social and environmental pressures on managers and their staff. This paper looks at the changing roles of two of the many groups of professionals associated with the mining industry - the equipment supplier and the mining consultant. The profiles of the ACME Group Pty Ltd, suppliers of ventilation equipment and ancillary canvas and plastic products to the mining and construction industry, and Tennent, Isokangas Pty Ltd, Consulting Mining Engineers, are presented.

Jan 1, 1998

Ion exchange resins are an attractive alternative to activated carbon in both column and resin-in-pulp processes for the recovery of gold from cyanide solution. Resins are widely used for this purpose in the Soviet Union apparently in preference to activated carbons.A wide range of resins are available and the high level of resin technology is demon-strated in the resin processes used to recover uranium.The anionic gold complex, Au(CN) 2 , is selectively adsorbed onto weak and strong base resins. However other anionic cyanide complexes, cyanide ions and other anions from the process water are also adsorbed onto resin sites. Resin selectively for gold is not as high as it is for activated carbons. As a result similar gold loading capacities are obtained for resins and carbons when used in plant liquors.

Jan 1, 1984

By A Purchase, C Stacey

The procedure for operation of deluge systems installed in road tunnels is still a subject of debate. The work undertaken in this paper assists in the understanding of the effects of deluge in road tunnels, and thus aims to help inform the development of operational policy. Analysis was undertaken using computational fluid dynamics (CFD) simulations to help explore the deluge interaction with the tunnel ventilation (including smoke exhaust) and combustion products. It was found, for the scenarios considered, that: Deluge activation can decrease the required critical velocity for smoke backlayering, and this in turn can improve the effectiveness of a smoke exhaust system.The dominant parameter for deluge effectiveness is the vehicle configuration, with shielded scenarios (such as a fire in the passenger compartment) showing almost no water reaching the fire. The water delivery rate (5 mm/min versus 10 mm/min) has only a minor effect on the smoke duct damper inlet temperatures and downstream smoke temperatures for small fires (5 MW). For large fires (50 MW) the higher water delivery rate gives slightly improved performance (lower damper inlet temperatures and lower downstream smoke temperatures). A one-dimensional transient tunnel model incorporating different operational and deluge response policies (ie deluge activation times) was developed. It was used to examine the influence of different operational parameters on life safety risk and tunnel damage risk. It was found, for the scenarios considered, that: The life safety risk for different scenarios has a sensitivity to deluge activation policy with the case of delaying the deluge activation for a long time giving the worst outcomes. However, the most critical parameters for life safety risk are operator response time (for all response activities, not just deluge) and the type of fire (configuration, size and growth rate).There is a reduction in risk of tunnel damage when the deluge is activated earlier, although the fire configuration (ie whether or not the seat of the fire can be reached) has the greatest influence on the outcome. It is concluded that the deluge activation policy should be case-dependent. It will depend on the tunnel, the safety systems provided, and most particularly the vehicles involved. The current policy in Australian tunnels is for manual activation of the deluge by the tunnel operator as soon as practical after the fire is confirmed (see also PIARC, 2007). This is a good policy. However, future work may be helpful to improve the skills of operators to make the best judgement as to when deluge should be activated, balancing all risks. This work could include research to further the understanding of deluge and fire in road tunnels, training programs and consideration of historical fire events.

Jan 1, 2008

By S N CARRAS

Ore reserve estimation is a procedure involving data collection, data storage and judgement and assumptions about geology mining and metallurgy. Calculations are based on these assumptions and an economic analysis on projected cash flows is carried out. Ore reserve estimation must therefore be subjective and will always depend on the extent to which the assumptions used in arriving at the estimate are correct. This paper is an attempt to summarise the many aspects that can contribute to ore reserve problems and to offer some suggestions on how to minimise these problems. For further details on specific concepts readers are referred to the detailed descriptions in the referenced papers.

Jan 1, 1992

By S H. Begg

"*This is an abstract only*Most technical and economic analyses are performed to reduce uncertainty to help make decisions. Decision-making is about ranking alternatives - rarely are precise predictions required, if even possible. This simple observation has profound implications for modelling approaches, how they deal with uncertainty and the reliability of information provided by subject matter experts.CITATION:Begg, S H, 2013. Some reflections on uncertainty, decisions, models and people, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 3-6 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

Mining of narrow vein mineralisation, invariably depending on the mining method selected, involves the extraction of both ore and waste rock. The level to which mining of waste rock can be minimised depends on numerous factors, but particularly the thickness and dip of the deposit. Resue mining is a method of mining that allows split face firing within stopes to allow waste and ore to be mined separately, allowing dilution to be minimised. This paper examines the technique of resue firing and its applicability to the mining of narrow vein deposits. Particular emphasis is placed on the conditions in which resue mining presents a suitable option for mining of narrow veins.

Jan 1, 2008

In order to realise seafloor massive sulfide (SMS) mining, the environmental baseline survey around targeted SMS mining areas and the creation of an environmental assessment technique suitable for quantifying the impacts of ocean floor mining are necessary. The targeted areas generally host large chemosynthetic communities in association with active hydrothermal venting. The ecosystem structure around the chemosynthetic communities has not been clarified yet in macro-scale or quantitatively. The systematic approach and plan for the baseline survey and the environmental assessmentÆs basic studies are introduced. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Launching the Queensland Water Plan 2005 - 2010 in August 2005, Premier Peter Beattie compared the stateÆs water resources with liquid gold. QueenslandÆs peak industry body for the minerals and energy sector, the Queensland Resources Council (QRC), believes the analogy is appropriate. During early development of an industry water strategy, it has become apparent that water is like liquid gold, in that it is revered, hoarded, recycled, priced on purity, a magnet for speculators, both difficult and expensive to transport effectively, heavily regulated and fundamentally linked to issues of security. To date it has generally been economic and relatively straightforward for the resources sector to secure water. Although production has not been compromised, this must not be grounds for complacency as there is every indication that water will continue to become increasingly expensive, more tightly regulated and, relative to a growing demand for a finite water supply, increasingly scarce. During 2006, QRC has developed and is implementing a voluntary industry water strategy to address a range of challenges confronting the resource sectorÆs security of access to water. As a consequence of, at times, protracted community consultations over QueenslandÆs catchment-based water planning processes it has become clear that many community stakeholders have outdated perceptions of the stateÆs resources sector. Once established, QRCÆs water strategy will incorporate a community engagement campaign to present the industryÆs credentials as a leader in water resource management. The development of QRCÆs water strategy, and the challenges the strategy is designed to address, provides insight into the fundamental reforms that are occurring in how water is managed and regulated in Queensland. These reforms have implications for how government policies are designed and administered and also for how industry engages with communities during this transition process.

Jan 1, 2006

By K Whelan

The Land Access Branch of the Mines Division of the Northern Territory Department of Mines and Energy is responsible for Aboriginal Liaison and cross-cultural matters that affect the Department. In essence, it exists to provide a basis for communication between the Department, industry. Aboriginal organisations and Traditional Owners. The paper outlines the various ways in which this is accomplished including the preparation of detriment submissions for pending land claim hearings, the use of promotional material to support access to Aboriginal Land for NTGS Mapping Programs and field work, and advice/assistance on exploration and mining issues.

Jan 1, 1994

By T Higuchi, T Yamamoto, K Takehara

Iron ore fines are used as raw materials for sintered ore for blast furnaces in the world. Since the production and quality of sintered ore have a great influence on the stable operation of a blast furnace, many technologies were developed for controlling the heat profile in the sintering machine, which largely affect the sintered ore properties. In particular, the influence of oxygen in the suction gas, which plays an important role in combustion, was investigated over the years. It is known that increasing the oxygen ratio by about 30 per cent not only significantly improves the combustion rate, but it also increases the strength and yield of sintered ore. However, the details of the mechanism for improving these qualities are unknown. In this study, we investigated the influence of oxygen enrichment at higher ratios (O2: 21–40 per cent) and tried to understand the sintering behaviour enhanced by oxygen. The effect of oxygen enrichment on sintered ore quality and the heat profile were evaluated by sintering tests using a quartz glass pot. From the results, sintered ore yield had a maximum value for O2 = 30 per cent, but strength was increased for O2 = 40 per cent. From heat pattern analysis, it is clear that the high temperature holding time also reached a maximum at O2 = 30 per cent. Furthermore, we found that with increased oxygen ratio, the combustion speed (flame front speed) was increased, but the area of combustion was enlarged. It is considered that there could be a maximum oxygen ratio value for the yield from the balance of these positive and negative effects on high temperature holding time. To clarify the reason for strength improvement, thermodynamic calculations were performed and it was found that melting behaviour could be improved by changing the oxygen ratio.

Sep 18, 2023

Mine planning studies of iron ore deposits are often based on resource models generated by ordinary kriging. Ordinary kriging aims for local accuracy to minimise the variance of expected estimation error but this is at the expense of reproducing variability of the original sampling data. Hence mine planning studies using kriged models are likely to underestimate product variability, and the required blending and stockpiling capacity to reduce variability to an acceptable level. Instead, conditional simulation models of the main chemical variables in iron ore are able to reproduce likely variability to be encountered during mining and processing. This approach is demonstrated in a case study of the Weld Range bedded iron ore deposit in Western Australia, with a comparison of ordinary kriging and conditional simulation models. Conditional simulation models suggest that, compared with the single ordinary kriging estimation, there is likely to be far greater block variability for iron and impurities, a greater requirement for stockpiling and blending capacity, highest variability in initial years of mining and less variability in later years of mining for deeper ore. The conditional simulations provide a more realistic range of mining outcomes for production of high-grade ore, which may be seven per cent less than in the kriged model, as well as for lower expected project net present value (NPV). In year one, the kriged model is conservative for NPV; however, in later years two to five the kriged model has higher NPV than most conditional simulations, suggesting expected NPV based on the kriged model may not be achieved. For improved decision-making in mine planning, a complete range of possible outcomes from conditional simulations of the deposit should be considered rather than relying on a single kriging estimation that may be an end member case in the range of possible mining outcomes.

Jan 1, 2009

ITSL Technology group employs around 100 people at Mississauga in Canada. Its long and proud history as a driving force for the worldÆs nickel industry continues, progressively adapting to meet IncoÆs ongoing development needs. The nickel industry, unlike many others in the minerals processing world, has not evolved into one or two narrow technology paradigms. Rather, each process requires a degree of optimisation to meet the characteristics of the ore. Without a competent team to address this complexity, the uncertainties that arise can greatly increase the risk (and costs) associated with the nickel industry developments. The development work carried out at ITSL Technology ranges from milling and metallurgical processing of ores through to development of value added products for the battery and electronics industries. It covers routine evaluation of ores for exploration (mine planning and greenfield), and provides on the ground support to bring specialist technical perspectives to site-based projects. In recent years, ITSL Technology has had as its particular focus the process development and commissioning support for IncoÆs major projects. Over the next several years, Inco will commission its Goro laterite operation, design and construct the further processing facility for VoiseyÆs Bay, undertake major upgrades at Sudbury, Thompson and PT Inco, and bring forward some additional resources currently in the exploration stage. The appropriate mix of both internal and external resources to effectively manage this project portfolio will prove critical to success. The key to ITSL Technology meeting these development challenges has been in working closely with its internal customers to ensure alignment of the value proposition, to identify the critical issues to be managed, and to understand the deliverables required. This paper discusses examples to reinforce these principles in the definition and development for two different projects; processing of VoiseyÆs Bay ores and concentrates and resource optimisation at Thompson.

Jan 1, 2006

By Gochin RJ

This paper focuses on measures of the economic significance of mineral exploitation and processing activities, such as beneficiation, refining and smelting. Empirical measures are suggested to quantify the relevance of the degree processing within a nation's mineral industry. The most useful, based on the input-output econometric framework, are used to establish the magnitude of links between the mineral industry and its satellite activities and for the appraisal of large, non-marginal projects. The input-output impact analysis is refined to allow for country specific behaviour and synthetic indices for the appraisal of investments in the mineral sector are developed. These indices are further improved with the introduction of shadow prices to incorporate socio-economic issues. They are useful to direct mineral policy decisions and several investments towards the most promising objectives for national goals. Finally traditional methods for the appraisal of small scale, marginal, mineral projects are assessed where local impact and regional development issues are more relevant than national ones.

Jan 1, 1993

Over the past several years, copper prices have surged from under a dollar to over three dollars a pound. However, the long-run trend in real copper prices since at least the early 1970s has been sharply downward. While many now contend that the long-run trend in real copper prices is now upward, the result of structural changes in this market, others are sceptical. Nor is copper unique; the prices for a number of other metals, including aluminium, iron ore, lead, nickel and zinc, have followed similar patterns. This paper examines the forces behind short-run and long-run trends in metal prices. It first focuses on the short run, where it argues that shifts in demand are largely behind changes in prices. It then turns to the long run, where it concludes that production costs and supply largely govern price trends. Finally, it explores several implications of these findings, including those for diversification and market risk, for forecasting mineral prices, for assessing the growth of metal demand in China and elsewhere on metal prices, and for changes in the long-run price trends.

Jan 1, 2006

Mine Dewatering for reoccupation of a flooded mine requires rehabilitation and recommissioning of shaft and sane level functions to provide safe efficient access, services and logistics, as well as securing connections with all exposed workings. The objective is the earliest secure reoccupation of the target depth horizon for minimum water pumping, consistent with an appropriate investment and optimum schedule of operating inputs to the dewatering, redevelopment, services and consolidation processes. Strategy must focus on recommissioning of relevant functions in the shaft and at stage pumping horizons, advance of logistics close to pumping and rehabilitation, management of the secured exposed workings. The progress must be systematic, sustained and integrated, and must be secured against risk and uncertainty. There must be a strategic capability to respond effectively, and manage interruptions to processes, conditions requiring higher or different resources, and contingencies which affect schedule, budget or risk profile for the continuing programme. Planning must aim to reduce or contain risk or uncertainty elements and contingencies, limit interruption frequency and severity, identify and provide the capability for efficient responses. It is appropriate to model and simulate the reoccupation analogous to a mine initial development production programme. Only minor changes to relationships and relativities of models for Capital works, Operations (Production and Development) and Services/Logistics are needed but the model for management of workings is more relevant than that for depleted workings in an operating mine because of the water and other transfers. An important difference is the unsteady state of operations which requires probabilistic modelling of availability and utilization of equipment and processes.

Jan 1, 1988

By M Reisi, H Waterer, M Savelsbergh, F Engineer

The Hunter Valley Coal Chain Coordinator (HVCCC) Limited is the primary planning organisation responsible for the export of coal through the Port of Newcastle, Australia. HVCCC stakeholders include producers (mining companies), rail track owners, above rail operators, and terminal operators. The HVCCC is tasked with coordinating the activities of all the corresponding parts of the coal export supply chain so as to maximise the system efficiency. The HVCCC also has a forward looking planning role: with demand for coal expected to double in the next decade, strategic capacity planning is a core activity for the HVCCC. Optimisation and simulation models are key aids in such activity. They are used to suggest and evaluate infrastructure expansions and operating policy changes. These models require input data in the form of shipping stems, which are arrival streams of ships at the port, together with their cargo types and composition, and date and time of arrival.Although everyone is familiar with the expression ægarbage in equals garbage outÆ, relatively little research is dedicated to the issues surrounding input data generation. In this research we seek to redress this, and have developed a method for generating high quality shipping data. Shipping stems used as input should be realistic, reflecting key characteristics of historical patterns. They should accurately represent future demand scenarios. Yet they should also have controllable parameters that can be used to test what-if scenarios, such as are required by the HVCCC to answer questions about future infrastructure or operational plans.Here we review our process for achieving this, and give a case study analysing the effects of different shipping stems on the performance of the coal chain, as measured by a capacity assessment tool. The latter is an optimisation model that takes shipping stem and infrastructure data as input, and calculates key supply chain performance metrics. The potential benefits of alternative demand management strategies are analysed by measuring the performance of the coal chain given different shipping stems obtained via the stem generatorÆs controllable parameters.

Sep 26, 2011