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By S. Caron, P. Radziszewski

Industrial practice in mineral processing shows that an important problem in understanding and monitoring in-mill parameters is due to the lack of fundamental knowledge and appropriate sensors. However, over the last decade, Discrete Element Method (DEM) modelling has shown an interesting potential in describing the fundamentals of grinding mill behaviour, in improving the understanding of internal grinding mill dynamics, and in developing solutions to industrial practice. With the objective of bringing this modelling technology into the concentrator control room to assist operators, this paper aims to describe the main elements needed to apply this emerging and developing technology to on-line mill performance monitoring.

Jan 1, 2004

By R. Anthony Hodge

1. Today?s Reality: Voisey?s Bay EIA Activities of the Canadian Environmental Assessment Agency The Tulsequah Chief Decisions The Bank of Montreal The World Bank World Business Council on Sustainable Development The Government of Canada Many company policies

May 1, 2002

By Colston M. B, Johnson I. D

The importance which matters of social welfare and environmental quality have assumed recently is the underlying theme of this paper. Demands for infrastructure reflect the change in emphasis from economic and technological development to those issues which affect the total well-being of the community. To put the importance of social change in perspective, examples are cited and a theme is developed which underlines the relevance of changes in public attitude and in government policies on mineral exploitation and related development and on the regimen of associated infrastructure sought. Planning on a long term or strategic basis and on a broad scale is put forward as an effective means of identifying changing social attitudes for the purpose of framing government and corporate policies. As a prelude to a section in which a description is given of a novel 'services baseline' concept and its use in the assessment of the current backlog of services

Jan 1, 1977

By P. Christmann

"In June or July 2005, the European Commission will present its Thematic Strategy on the Sustainable Use of Natural Resources proposal to the Council and European Parliament, one of the seven Thematic Strategies to be developed and implemented under the 6th European Environment Action Programme in support of the European Union’s Sustainable Development Strategy defined by the European Union’s Head of State at the Göteborg European Council, in June 2001. The time scale for this Thematic Strategy is 25 years (2005-2030). This paper discusses some of the key issues related to the EU minerals and metals industry that needs to be addressed by the Strategy. These are: - the need for access to mineral reserves in the EU and abroad; - the need to strenghten the capacity of developing countries to sustainably promote and regulate the use of their mineral potential; - the need for an EU mineral resources intelligence capacity. There are additional important needs, which are not discussed in this paper, such as: - the need to foster further innovation in mining, ore beneficiation and metallurgical technologies; - the need to integrate and simplify the exisitng complex regulatory framework applicable to the EU mining industry and to effectively implement existing legislation."

Jan 1, 2005

By Y. Rajpal

The Hedley and Grant pillar strength formula is widely used within the South African mining industry to calculate pillar strengths in bord and pillar mining layouts, and is currently being used at Bathopele Mine. Bathopele is an operation of Anglo American Platinum near Rustenburg, mining the UG2 reef at depths ranging from 40 m to 300 m below surface. The formula includes a parameter K, which is a downrated uniaxial compressive strength value of the rock, used to calculate the strength of a pillar. At Bathopele Mine, for the shallower areas Less than 150 m the value was 33 MPa, but this was increased to 44 MPa due to the fact that rock mass conditions improved and there were no incidence of failure in the shallower areas. Underground observations showed pillars to be stable with no signs of failure, and it was questioned whether the design was not still too conservative, resulting in sub-optimal extraction ratios and consequently a loss of revenue to the mine. A trial mining section was started at the mine where the pillars were reduced from 6 m x 6 m to 5 m x 5 m and the pillar behaviour was monitored for the onset of failure. Numerical modelling was conducted using the TEXAN code to back-analyse pillar stresses in order to find a more realistic value for K. Results from the trial section indicated that the pillar design was in fact too conservative, and the value for K was adjusted to 54 MPa for future designs. This paper details the findings from underground monitoring and numerical modelling results, and includes details for further calibration of the K value in order to further optimize the extraction of the orebody.

Jan 1, 2012

By Francis Kendorski

The mining engineering design professional has limited practical and reliable tools for planning successful room-and-pillar stone mines using readily-available and collectible information. Three techniques are in common use today: the hard rock CANMET method of Hedley and Grant, the hard rock method of Stacey and Page, and the oil shale method of Hardy and Agapito. Other methods have been proposed, such as the USBM method of Obert and Duvall, the CSIR/Penn State method of Bieniawski, and the soft rock confined core method of Abel, Wilson, and Ashwin. However, the latter have practical shortcomings when applied to room-and-pillar stone mines such as developed for construction aggregate production. Ideally, the use of multiple techniques resulting in the same acceptable and reliable answer is the goal. Recently, in several underground stone mines areas of undersized pillars were examined. These undersized pillars apparently resulted from non-adherence to a mine plan. These undersized pillars now exhibit strong evidence of incipient failure such as slabbing, opening of through-going fractures, and hour-glassing. This situation allows examination of pillar designs at a ?safety factor? of essentially one. This rare opportunity allowed the examination of the suitability and adjustment of the first three design methods discussed, resulting in greater overall confidence in the methodologies.

Jan 1, 2007

By G T. Jemwa, F Rousseau, F J. Wolfaardt, J A. M Rademan, P W. Smit

Mining companies are increasingly faced with the challenge of reducing operating costs while maximising throughput and profitability. At the same time, the grade and quality of treated ores are becoming poorer and more variable, resulting in suboptimal process performance.It is now widely accepted that strategies to drive operational goals must revolve around improving plant availability, reliability and process efficiency. In particular, progress in plant automation and control systems has seen a trend towards unified frameworks for control and optimisation of mineral processing plants. These frameworks seek to seamlessly integrate different roles and tasks involved in process operations - IT, automation, plant maintenance and operations. An integrated solution framework for reducing process variability, increasing process efficiencies and maximising plant availability and reliability is discussed within the context of a typical milling circuit. The framework exploits a real-time analysis ægapÆ evident in production operations that prevents timeous identification of equipment and process failures. This is achieved by leveraging predictive analytics for equipment health monitoring, control loop monitoring and advanced regulatory control solutions towards enhanced process performance, improved asset management and regulatory compliance. The framework provides for early and actionable warnings on equipment and process degradation using real-time operational data.Resolving these problems can potentially avoid unplanned downtimes, process instabilities and other operational surprises, thus ensuring optimal plant throughput and optimal process behaviour for improved recoveries. Integrating control systems and plant automation with advanced analytics to analyse and optimise processes enables operations to achieve reductions in the variability of key process parameters. In addition, early detection of equipment malfunction or suboptimal process conditions leads to improved equipment availability and reliability. Ultimately, these operational gains reflect in profitability because of plant throughput and recovery gains. These benefits are demonstrated using data from a South African gold mining operation, where such an integrated asset and process health monitoring framework for process optimisation has been implemented.CITATION:Jemwa, G T, Wolfaardt, F J, Smit, P W, Rademan, J A M and Rousseau, F, 2013. Towards an integrated framework for asset and process health monitoring and optimisation on a milling circuit, in Proceedings World Gold 2013, pp 137-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

"In mining operations, it is widely accepted that strategies to drive operational goals must revolve around improving plant availability, reliability and process efficiency. In this paper, an integrated solution framework for reducing process variability, increasing process efficiencies and maximizing plant availability and reliability is discussed within the context of a typical milling circuit. The framework exploits a real-time analysis “gap” evident in production operations that prevents timeous identification of equipment and process failures. This is achieved by leveraging predictive analytics for equipment health monitoring, control loop monitoring and advanced regulatory control solutions towards enhanced process performance, improved asset management and regulatory compliance. The framework provides for early and actionable warnings on equipment and process degradation using real-time operational data.INTRODUCTION The changing landscape of gold mining and processing presents many challenges that threaten sustainability of existing (marginal) operations as well as deter investment in new projects. As existing “shallow” ore resources become depleted, mining operations are increasingly treating low-grade ores with complex and randomly variable mineralogical characteristics. For example, in South Africa, historically one of the major gold producers, the average grade of ore treated has been decreasing from averages above 4.5 – 5 g/t to current grades averaging less than 3 g/t within a decade (Chamber of Mines, 2012). Moreover, lower tonnages are being treated as a result of the narrowing of the available resource base. Also, the regulatory framework has tightened over the years due to heightened concerns on the safety, health and environmental impacts of mining and related activities."

Jan 1, 2014

By G. C. Hall, B. E. Hobbs

Giant gold deposits are considered products of crustal-scale systems. Reduced fluids stored in mid to lower crustal reservoirs were discharged into mid to upper crustal sites of deposition. Elements of the architecture include crustal-scale structures, reduced packages of rock and regional seals. Gas-rich aqueous fluids were common but non-aqueous fluids may have been significant in the deeper parts of the systems. Fluid fluxes in over pressured domains were maintained by porosity waves. Abnormal heat input from the mantle may not be required once the systems were perturbed. Fluid-mixing and hypogene enrichment were probably the most significant precipitation processes.

Jan 1, 1999

By A Trench, S Ulrich, S Hagemann

A synthesis of reported All-In Sustaining Costs (AISC) for 57 Australian gold mines in the period 2014–2016 reveals for the first time the clear influence of grade upon cost performance, most evident in gold-only underground mines. Past syntheses of costs on a single quarter basis have viewed grade as potentially subordinate to other factors such as production scale, mine geometry, mineralisation style and a combination of other mining-related costs. Better understanding of the grade to cost relationship on both an individual mine and whole-of-portfolio portfolio basis is needed. Insight into the roles and trade-offs between other cost-determining factors will aid the future sustainability of the gold mining sector in Australia and assist in targeting prospects for future resource growth and development. While the overall trend is toward higher-grade mines displaying lower costs and vice versa, the grade to cost functions appear radically different between mines based on time-series data. The median cost of Australian gold production in the final quarter of 2016 was A$1081/oz. The threshold for lowest cost quartile production was A$965/oz. Underground production now dominates Australian gold output – with 71 per cent of ounces originating from operations that are either entirely underground or hybrid pit/underground mines. Scale economies are evident, with smaller mines predominately among the higher cost producers. For mines of equal grade, open pit mines are lower cost than underground operations. Reserves are modest, with a median mine life for underground operations of 4.7 years based on current production rates. Reserve additions at mines are likely constrained not only by the finite nature of mineralisation at each mine but also by the geometrical difficulty of accessing suitable drilling locations to test for reserve extensions.CITATION:Ulrich, S, Trench, A and Hagemann, S, 2017. Towards an understanding of production costs at Australia’s underground gold mines, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 241–250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By PEILIN LAN, LEONARD HILL, SIMON TIMBILLAH, BERNARD FOSU, CESAR SOSA-BLANCO

The use of sodium hydrosulfide (NaHS) in most of the operations in by-product molybdenum flotation comes with safety concerns and, in some instances, a high reagent cost. Engineered solutions at the various operations where NaHS is used have reduced the possibility ofH2S gas evolution immensely. However, the threat of exposure remains, and this, coupled with the high dosages of NaHS consumed, supports the continued search for alternative depressants. This paper focuses on efforts to study the applicability of disodium carboxymethyl trithiocarbonate (DCMT), an organic depressant, as an alternative to NaHS. Benchscale rougher flotation results for samples from the Sierrita Cu–Mo plant showed the best DCMTperformance at 8 kg/t of DCMT and pH=10.5 with 30 min of shear conditioning and 10 min of flotation conditioning time. The Aminpro plant model simulation confirmed that DCMT with 4–8 kg/t under certain shearing and conditioning times achieved superior or equivalent Mo–Cu separation efficiencies when compared to NaHS.

Apr 19, 2021

By B. Genc

Safety in South African mines is a subject of significant interest, since many mining companies are experiencing production deficits due to safety-related stoppages. In this paper, safety data from the South African platinum mining sector is analysed for the period 2006 to 2010. The data was obtained from company annual reports as well as the Department of Mineral Resources, and analysis in the study is limited to injury and fatality data only. The overall safety performances of companies in the sector are compared, and opportunities for benchmarking and recognising potential sources of best practice amongst platinum miners are identified. Improving safety usually incurs a cost, and mining companies are particularly conscious of the importance of controlling costs. However, cost considerations often deal only with direct costs, and it has been shown that indirect costs are usually far more significant. Therefore, a greater safety spend will usually result in the creation of value for the mine since it will reduce the indirect costs associated with accidents. The results of some recent research in this area are presented. In this light, where available, the financial performances of mining companies in the sector, obtained from published annual results, are included in the benchmarking exercise to determine whether there is any correlation with safety performance.

Jan 1, 2012

By G. van Aswegen

Seismic monitoring became commonplace in the deep South African gold mines in the early 1990’s. The discipline has, to a large extent, developed beyond the ‘research’ stage, and a ‘Guide to Seismic Monitoring in Mines’ has been accepted by the Department of Minerals and Energy1. Although ongoing research is a requirement for the achievement of all the objectives of seismic monitoring in mines, sufficient knowledge exists to apply seismic monitoring for routine seismic hazard assessment as an aid to risk management. The design and management of seismic monitoring systems can be tested against requirements spelled out in the ‘Guide’. Assuming the seismic monitoring system performs as per requirement, the best practice for routine seismic hazard assessment in mines includes • Long term seismic hazard assessment: through back analysis of seismic data and correlation with numerical modelling output, reasonable tests for planned mine designs are possible. • Medium term seismic hazard assessment: o Spatial analysis through contouring of seismic strain related parameters, with superimposed contours or event plots of stress related parameters allow the delineation of potential instabilities in space. o Quantitative and statistical analyses of seismicity in smaller spatial units (usually encompassing production sites) allow the comparative seismic hazard rating of different areas/sites so that rock engineering input and risk management can be optimised • Short term seismic hazard assessment relies mainly on time history analyses of particular seismicity parameters. The temporal patterns are controlled by a combination of temporal and parameter filters, the optimisation of which determines the success rate.

Jan 1, 2003

By Thomas Boundy, PATRICK TAYLOR

Indium recovery from liquid crystal display (LCD) waste has been the subject of over 50 peer reviewed publications over the last decade; however, the first commercial recycling facilities are just beginning to be built. The low value of indium in the LCD screen material has posed a major challenge to would-be recyclers. Uncommon material combinations and geometries have further challenged development. A review of published literature regarding extraction of indium from LCDs will be presented and themes of advantageous processes will be highlighted. Barriers to rapid expansion of any recycling technology in the form of manufacturin gpractices, environmental regulations, and geographic constraints will be discussed.

Mar 1, 2018

By Galetakis M., Deligiorgis B., Xiroudakis G.

Fragmentation prediction is important in surface mining to optimize downstream processes such as loading, hauling, comminution, and beneficiation processes. Traditional approaches, such as the Kuz-Ram model, image-based fragmentation analysis, and numerical simulations, rely heavily on large datasets acquired after blasting. Moreover, due to the inherent limitations in each method there is an underestimation of fine and coarse fragment sizes, when applying these models without prior knowledge regarding the fragmentation distribution. These drawbacks are restricting their use only in post-blast parameter prediction. In response to these inefficiencies, this study presents a deterministic fragmentation prediction methodology based on a single-blasthole model. The model simulates the formation of the damage zones around a blast hole based on the number of cracks within a distance from the centre of the blast-hole and correlates them with an estimated fragment size in each domain. A fragmentation distribution from the literature is employed to validate the proposed approach and the results are compared with those generated using a modified Kuznetsov model. This approach aims to enhance blast design decisions by enabling pre-blast fragmentation prediction. Based on this, blast designs could be estimated depending on the desired fragmentation before blasting, giving the opportunity for a tailored to local rock properties optimization.

Jan 26, 2026

By E. Lampard

Mines must manage variability from within their operations as well as those imposed upon them by external forces. This paper provides a framework to manage both internal and external variability through the review and adjustment of the mine plan where applicable to minimize lost production and maintain operational safety. KEYWORDS Mine plan, mine schedule, variability, safety, lost production, float days, update, adjustment, operations, Maintenance

May 1, 2011

By T. G. Joseph

Mines must manage variability from within their operations as well as those imposed upon them by external forces. This paper provides a framework to manage both internal and external variability through the review and adjustment of the mine plan where applicable to minimize lost production and maintain operational safety.

Nov 1, 2011

Towards Improved Hydrocyclone Models - Contributions from Computational Fluid Dynamics

Sep 13, 2010

By P. R. Warner

This paper reviews the development of certain aspects of the electrical specifications of Anglo American?s suite of specifications for gearless mill drives (?GMDs?). These specifications are based on experiences in both Anglo American?s and others? operations, benchmarking against large hydro generators, the advice of industry and university experts, and continuous close co-operation with OEMs. To achieve a step change in availability additional final testing and electrical protection have been implemented, insulation requirements have been specified for machines to be operated at high altitude and clean area and access control systems have been developed.

Jan 1, 2012

By G. Hamel

The LCL&L process (Low Caustic Leaching & Liming) is a patented hydrometallurgical route developed by Rio Tinto Alcan (RTA) to economically process spent pot lining (SPL) generated by aluminum cells. The three resulting end-products (carbonaceous, fluorinated and caustic liquor) are inert and have valorization possibilities. An industrial size pilot plant located in Saguenay (Quebec) was inaugurated in mid-2008 to demonstrate and optimize the technology. This paper describes characteristics of the LCL&L process and the experience acquired by RTA since the plant's start-up, including ramp-up capacity and technology challenges that were overcome. Possible end-products valorization methods are also presented. The carbonaceous end-product can be separated into carbon and brick rich fractions and used as either alternative fuel, reducing agents, or as raw material for third party processes. The development of a conversion process for the fluorinated end-product would allow its reuse as a substitute to fluorspar mineral for aluminum fluoride production. Finally concentrated caustic liquor is already valorized at the nearby RTA Vaudreuil alumina refinery.

Jan 1, 2011