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By N Haque, S Northey

Water in mining, mineral processing and metal production on a life cycle basis has been at the top of agendas for various industries, government agencies, research organisations, academic institutions and communities. As a result, a number of water footprint assessment methodologies have been developed. However, their practical applications in mining and mineral processing industries with specific case studies are still rare.A key objective of the Minerals Down Under Flagship is to contribute to the long-term sustainability of the Australian mining and mineral industries. Researchers in the Mineral Futures theme have developed robust assessment methods to evaluate the impact of mining and minerals technology development on the environment. The future of mining and the mineral industry is strongly linked with its sustainability - better water management strategies will need to be implemented.Life cycle assessment (LCA) has been a recognised method for measuring the environmental impacts of products, processes and services. It provides a scientifically sound method of comparing products and processes using a common basis and identifies so called æhot spotsÆ and opportunities for reducing environmental impacts. The water footprint of mining, mineral processing and metal production using an LCA basis is still scarce in the literature. Research methodology is now being applied in detail for copper, gold and nickel. A primary focus has been the relationship between ore grade and water use for which mathematical models are being developed. These types of models provide inputs for LCA of mining and mineral processing plants and can identify water saving opportunities through scenarios and process route analysis.CITATION:Northey, S and Haque, N, 2013. Life cycle based water footprints of selected mineral and metal processing routes, in Proceedings Water in Mining 2013 , pp 35-50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

Stilfontein Gold Mine, located approximately 160 km west of Johannesburg, produced both gold and uranium from 1952 through to the early 1990s. On decommissioning the mine infrastructure, treatment plants, rock dumps and three tailings facilities were left to be rehabilitated at considerable cost to the mining company. The community that had grown up with the mine and had settled in the mine village were faced with deteriorating socio- economic conditions.   Mine Waste Solutions (MWS), a company with a socio-economic Vision expressly created by DRD (Pty) Ltd and Fraser Alexander (Ltd) for the purpose, took over the mine surface infrastructure with the objective of closing it down in an economically sustainable manner by recovering materials, converting mine infrastructure to useful purposes and re-mining of the tailings to recover residual gold to finance the project. A business case was prepared and presented successfully to investors and bankers and the project was commenced in 2003.   The paper covers the scope of the project and gives an account of the practical lessons that were learnt as the project developed over a period of five years. Key technical issues that are covered by the paper are the re-mining techniques that were deployed to clean up the old tailings dam footprints and the selection of the deposition site to minimise the incremental impact associated with the tailings and concurrent rehabilitation of the facility. In addition the paper will outline the positive benefits that were generated for the community and the improvement that was achieved in the physical environment.   The paper illustrates clearly how a mine can be closed in a manner that produces benefits for the community, the environment and the investor.

Jun 1, 2010

By N Tyson

Throughout Australia and the world, there have been in recent years a number of incidents involving the reaction of ammonium nitrate based explosives with ground containing certain types of sulphides. This paper presents a comprehensive strategy designed to identify, assess and mitigate the risks involved with blasting in areas of reactive ground. Undertaking blasting in reactive or potentially reactive ground involves a degree of risk, the level of which is dependent upon the controls in place for specific sites; this in turn depends upon the degree of sound reasoning and judgement behind the implementation of these controls. Implementation of controls to minimise the risk of incidents also involves a measurable increase in production and blasting costs. To achieve a balanced solution to this matter, decision-makers need to understand how the risks eventuate, how they should be evaluated, and how control measures reduce the risk. Also required is an understanding of how the problem affects the economics of the operation, and the magnitude of this effect. It is the aim of this paper to provide a structured approach to gaining this knowledge, so that mine management, the workforce and explosive suppliers may jointly develop more effective economic and safe blasting systems for potentially reactive ground. Using a combination of fault/event tree risk assessment and semi-quantitative analysis, a structured approach to dealing with the issue will be illustrated.

Jan 1, 2001

By G McCullough, J Els, J Bassan

Integrated Remote Operations Centres (IROCs) have a crucial role in optimising a mine’s carbon emissions, especially as industry faces an imperative to achieve net-zero emissions on an accelerated timeline. To meet this time pressure, operations must adopt a comprehensive approach to energy-related carbon management and history has proven that modern technologies cannot be simply bolted into existing operations. An IROC is the most dependable solution to enable a swift transition from strategy to operational tactics that support carbon optimisation. Achieving net-zero emissions requires addressing significant energy management challenges such as fleet electrification, integration of renewable energy sources and large-scale energy storage. These challenges demand a profound change in planning, managing and executing work at large operations. The key to overcoming these challenges is an integrated approach incorporating collaborative decision-making across the value chain and more sophisticated planning approaches. Additionally, closer integration with downstream processing offers opportunities for carbon optimisation across the value chain. This includes the ability to supply tailored products that meet more varied feed-requirements of customers transitioning to less carbon-intensive processes and developing collaborative decision-making across the entire steelmaking value chain (by incorporating steelmakers, transport, coal/natural-gas/hydrogen supply, energy supply and iron-ore supply). However, this requires significant improvement in collaborative maturity and integrated decision-making capability. Finally, the imperative to reduce carbon emission demands the introduction of a range of new technologies into existing operations. The new technologies will increase the operational complexity of the mines and IROCs will need to evolve capabilities to manage the increase complexity and support the effective operationalisation and integration of these new mining technologies. This paper outlines the new capabilities required and the role of IROCs in effective integration across the demand value chain. The focus is on building on the mining industries’ existing IROC experience and augmenting with processes, technologies and lessons from other industries.

Sep 18, 2023

By J Thoma, W Skinner, W Stewart, R Smart

The acid neutralisation capacity (ANC) of rock sample containing significant iron carbonates and/or reactive framboidal pyrite can be a difficult parameter to determine. Results indicated that negative ANC results can occur if reactive sulfide minerals are present; and an over-estimation of ANC will result if significant Fe rich carbonate minerals are present during industry standard ANC tests. In this paper we investigate these problems. Results showed that a significant lag period may be needed (up to 432 hours) after standard Sobek ANC type tests of siderite for the complete hydrolysis of iron released from this mineral. This even occurred with standard industry modifications that included the addition of two drops of hydrogen peroxide. In this work we use a modified Sobek test that included filtering, and thence continued hydrogen peroxide addition until there was no subsequent pH drop, followed by back titration to pH 7.0. Results indicated that the ANC for the siderite (after zero hours) was immediately comparable to the ANC determined after 432 hours lag by standard Sobek type tests; and a calculated theoretical carbonate ANC. Investigations of coal waste samples containing significant framboidal pyrite indicated that standard Sobek ANC type tests can result in negative ANC values due to the oxidation of this reactive pyrite. Because sulfide acidity is already addressed by the MPA calculation, the inclusion of sulfide acidity as part of the ANC determination is effectively biased towards acid generation and thus positive NAPP values. Negative ANC values cannot be ignored or assumed to be zero as this masks any actual ANC available within the sample, which may possibly affect AMD categorisation. This sulfide acidity can be factored out using the quantity of S in the ANC digestion liquor and knowing the non-acid generating sulfate content of the sample prior to ANC testing. Results indicated that incomplete iron hydrolysis at the completion of the Modified Sobek ANC test is not only a function of iron carbonate dissolution, but is also related to the dissolution of Fe-sulfate salts, and the oxidation of reactive sulfides such as framboidal pyrite.

Jan 1, 2003

By D M. Silva, J C. Alves

According to the literature, material transportation represents 50 per cent of the operating costs for an open pit mine. In this context, this paper proposes a multistage approach for dynamic truck dispatching in real open pit mine environments, implemented in the commercial package SmartMine®, marketed by Devex SA. The first stage of this approach defines the optimal number of trucks that maximises the tonnage production by means of a robust linear programming model, which considers the operational constraints of a real mining process. The second stage uses a dynamic dispatching heuristic joining computational simulation and multicriterion optimisation techniques for decision making for truck dispatching. Another relevant contribution of this work is the publication of realistic instances collected from a dispatching system managing an iron mine, containing information about the hauling and loading fleet, the equipment situation when the working shift starts, cycle times, the time line of special occurrences (such as equipment stoppages and loading equipment reallocation in order to satisfy the mine planning) and the tonnage produced. These instances were generated with the purpose of submitting the method to the test of a real situation that considers the uncertainties existing in the process studied. The proposed approach was validated by means of a discrete event simulation model applied to the previously designated instances. Using this multistage approach as a mechanism for dispatch decision making, it is shown that the haulage fleet productivity increased when compared with the real values reported from the instances. These results are important because they show that the proposed approach generates efficient dispatch decisions for trucks operating in a real environment, reducing operating costs, increasing production and making the mine more competitive.

Sep 26, 2011

By H R. C Pratt, G W. Stevens

Hydrodynamic and mass transfer performance are presented for a 72.5 mm diameter pulsed disc and doughnut column of the type used by Western Mining Corporation, Olympic Dam Operation, for the extraction of uranium from sulphate media using Alamine 336 as extractant. For the present purpose, 4.0 g/L sulphuric acid was used as solute. The mass transfer data were interpreted in terms of the diffusion model, thus accounting for continuous phase axial dispersion. The results indicated that an efficiency corresponding to approximately one transfer unit over the 1.0 m height of the column was obtained. This efficiency is comparable to that observed by Gottliebsen (1997) for a pulsed perforated plate column using 173 gm/L sulphuric acid.

Jan 1, 2000

By D Tuazon, M Powell, M Ziemski, G D. Corder

Although mining companies have made broad corporate-level commitments to adopt sustainability, there continue to be problems when attempts are made to adopt higher-level sustainability aspirations and translate them into appropriate targets and methods at the more-specific operational level. The integration of sustainability principles into minerals processing operational decision-making processes has unique challenges that are not addressed adequately by current tools and methodologies, yet impacts from operational decisions can have longer-term effects realised at closure and rehabilitation.This paper describes a proposed methodology to achieve the integration of sustainability at the operational level through a systematic and rigorous process of identifying and qualifying sustainability issues and opportunities in an operation. The methodology, starting from a sustainability point of view rather than an operational one, guides the identification of process issues and opportunities by examining the operation, unit-by-unit, similar to a Hazard and Operability (HAZOP) process. Each issue or opportunity is qualified according to its measurability, scopes of impact and consequences so that it may be understood fully and the correct engineering problems are formed. Through improved decision-making to account for broader sustainability factors, operations can better address environmental and social expectations and pressures (both corporate and community, as well as immediate and in the longer-term), whilst still delivering on operational and business goals.The methodology has been tested with two case studies at minerals processing operations. At one site, the methodology identified a dust issue which had considerable business risks (loss of valuable product) compared to conventional engineering analysis processes. The other site also benefited from using the methodology as an opportunity to improve the operation of the milling and flotation circuits was identified. The opportunity not only showed a potential to improve operational efficiency, but also potential improvements in water and energy efficiency and a resulting increased resilience against water and energy supply risks. It was important to utilise the holistic approach of the methodology in the identification of opportunities at this site; the goals of the operation showed a strong coupling between water and energy issues which would be difficult to overcome using the operationÆs current organisational model, which deals with such issues separately of each other.CITATION:Tuazon, D, Corder, G D, Powell, M and Ziemski, M, 2012. A practical and rigorous approach for integrating sustainability principles into decision-making processes at minerals processing operations, in Proceedings Life-of-Mine 2012 , pp 233-242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

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

Over the last ten years geological and mining software products have evolved greatly. Software companies developing such products have focussed almost exclusively on the development of technical aspects of the applications, addressing geological, ore reserve estimation and mine planning problems. These specialist applications, and the many other new technologies that are being developed by a myriad of niche developers, are an essential part of todayÆs hi-tech mining operations. Technology is also being used in many other areas to improve the mining process and there is no doubt that tremendous advances are being made in all these fields. Yet there is something missing. The manner in which the technologies are used and implemented has led to the creation of many independent and inefficient æislands of technologyÆ where a variety of products from different vendors are used to address different, but related problems. Problems occur with unreliable information, data duplication, data redundancy and transferring data between applications that may be incompatible or even run on different computer platforms. These problems impede the flow and availability of information and hamper day-to-day decision-making by mine management. A solution to this problem is to take a holistic view of all the various technical applications and incorporate them into a single information technology solution. This solution must encompass all of the information requirements of a mining operation and must provide facilities that address much of the modern thinking about mine management, including strategic mine planning, value management, key performance indicators, and maintenance of a mineral balance sheet. Gemcom is developing an Integrated Resource Asset Management System (IRAMS), which is an enterprise-wide integrated computer system that encompasses various applications typically found at a mining operation. The core component of the system is a common, open, industry standard database that can be shared by many users from each of the different departments at a mine. Around that central repository are the primary applications that provide the mine with information it needs to operate. Ensuring that the information is reliable, accurate, shareable, timely and consistent will eliminate many inefficiencies, and provide significant benefits to mining companies. In turn these benefits will lead to significant improvements in decision-making, productivity and profitability for the operation. The initial version of the IRAMS system is currently being implemented at the De Beers Venetia Mine in South Africa. The system is being built around a core repository using the Microsoft æBack OfficeÆ architecture, and incorporates key technical applications from Gemcom, Whittle, De Beers Technical Team, Wenco and JKTech. The benefits of enterprise-wide systems have long been recognised in the commercial arena and enterprise resource planning (ERP) systems such as SAP, JD Edwards and MIMS are becoming commonplace in the mining industry. The more forward looking software developers and mining companies realise the need for efficient management of the information gathered during the mining process and can see that the concepts used in ERP systems apply equally to the technical applications as they did to commercial applications. The use of IT in the mining industry has expanded tremendously over the last five years as enabling technology and management acceptance has become more prevalent, and there is considerable room for dramatic growth over the next five years. The evolution of geological and mining software has now reached the stage where mines will yield the greatest returns by integrating the applications used in each area of their operations.

Jan 1, 1999

In practice a sampling solution is a compromise of many requirements: the sample should be representative; the sampling system should also be reliable, less than 95 per cent availability restricts the use of the assayed sample for process control purposes; no sample is the worst sample, and investment costs and installation space/layout are frequently a restriction. For instance, online X-ray analysers for process control introduce a delimitation error by the nature of X-ray physics. Thus only in special cases a relative accuracy better than three per cent relative, as one standard deviation, is achieved. A sampling system for process control needs not to be, as representative, for so many sample properties, as one for composite laboratory analysis samples. Sampling system maintenance is also an important issue. There are many sampling systems in the industry which have been difficult to maintain and are in disuse for lack of resources or incentives to keep them running. Pierre Gy developed the most generally accepted sampling theory. One of the main principles is that all particles in a one-dimensional process stream should have equal chances of being included into the sample. A correctly designed and operated transversing cutter comes close to this goal but has limitations in temporal representativity. For slurries an acceptable solution in many cases is to use a fixed vertical cutter(s) in a position where the slurry is well-mixed by turbulence and other means. For online analysis, reliability problems are mostly related to faulty design or installation of the piping system to the analyser. Properties of material processed, process flow sheet and piping details before and after the sampler have to be taken into account when deciding on which sampling arrangement is appropriate. Guidelines and some solutions to these issues are presented in this paper.

Mar 1, 2010

There are many compelling reasons why correct sampling schemes should be standard practice in the mining industry, yet there are numerous examples where poor sampling practices are known to exist in the business yet permitted to continue. It is not just technical issues that can be ascribed to the reasons for the continued use of incorrect methods. This paper proposes non-technical reasons why incorrect sampling practices continue, and identifies potential ways to overcome them.

Mar 1, 2010

By J L. Stacey

The diverse priorities, drivers and concerns of multiple stakeholders in the minerals industry complicate the integration of sustainable development considerations into mine design, as well as operational and strategic decisions. The ability of the industry to address all role-playersÆ needs, or indeed, to achieve consensus among all role players on the plethora of sustainable development issues seems a noble yet unattainable goal. One of the difficulties in assessing the relative importance of sustainable development issues across many stakeholders is the inevitable lack of impartiality in valuing these issues. Starting from a premise that transparency and fairness of the process are absolute prerequisites for progress, but that consensus is not, an approach has been developed in which all stakeholders are asked to assess the importance of all other stakeholdersÆ priorities, excluding their own. The approach recognises that stakeholders have different levels of contribution, understanding, vested interests, and perceptions of legitimacy and entitlement, across the diversity of sustainable development issues and decision criteria. Using Triangular Value Analysis, the relative weightings of each of the stakeholderÆs priorities are determined through a regression-like technique. The uniqueness of this approach is the manner in which self-assessment bias and overemphasis of stakeholdersÆ own priorities are avoided. The methodology can be used for both internal and external stakeholders, and in conjunction with other group decision making techniques, such as the nominal group or Delphi techniques. This paper will illustrate how Triangular Value Analysis may be applied in the minerals industry to determine priorities in various decisions relating to potentially conflicting sustainable development priorities within the industry.

Jan 1, 2009

By H M. Parker, G Verly, T Postolski

Assessing the uncertainty and risk in mineral resource estimation is required for best practice and is implied by the public reporting codes in the categorisation of mineral resources and reserves. One industry best practice is quantifying the risk on future production for a given period, which can be done using two geostatistical approaches: conditional simulation and drill hole spacing studies based on estimation variances. Conditional simulation can provide a more complete and flexible answer to the problem, but it takes a fair amount of time to complete. Drill hole spacing studies are simpler, faster and can provide reasonable assessments of mineral resource uncertainty.This paper is a presentation of the principles, theory and practice of drill hole spacing studies. Various types of risk assessment are considered. Difficulties encountered in practice are discussed, and solutions are proposed. The important parameters impacting the results are reviewed. Examples of results and sensitivities are shown.CITATION:Verly, G, Postolski, T and Parker, H M, 2014. Assessing uncertainty with drill hole spacing studies – applications to mineral resources, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 109–118 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By G J. Halstead, R C. Steinhaus

The True Pipe® in-line sampler was developed in an attempt to address the need for a mechanically reliable and correctly designed sampler to suit one-dimensional pressurised slurry pipelines, often found in metallurgical process plants but for which no reliable and representative sampling solution as yet exists.The design, whose operation is based on the principle of symmetry, is described by Dominique François-Bongarçon (2005) with the synchronous opening and closing of relevant valves. It representatively isolates portions of the particulate material stream at predetermined intervals for effective extraction of primary increments for subsequent sample compositing.Theory of Sampling applicable solutions have proven elusive in flowing pressurised particulate material streams, with various attempts to date not having formulated a viable, mechanically reliable and acceptable design.Compliance to sampling theory is critical, and a number of tests were conducted where certain operating parameters were altered to determine their influence and sensitivity on sampling representativeness.The results of the initial series of tests performed on a carefully designed rig are presented, with additional work discussed for necessary investigation in the near future.Getting closer to a robust, economic and correct design for this challenging application in the minerals industry may now not be that far away. Plant management staff will see improved metallurgical mineral balances around their process plants and significantly reduced sampling discrepancies, particularly in tailings applications. Improved quality control is now possible where, due to plant head room constraints, classical cross stream sampling methods cannot be employed.CITATION:Steinhaus, R C and Halstead, G J, 2014. True pipe sampler – a correct design utilising the principle of symmetry in pressurised slurry particulate streams, in Proceedings Sampling 2014 , pp 127–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By A Tang, K Ringwood

"Water is increasingly being recognised as a material business risk that many companies are still not well-equipped to deal with. Despite a raft of water-risk focused initiatives, methodologies and guidelines, the challenge of managing the strong link between the technical and operational water issues, along with the growing external challenges and interests in water, remain a significant risk to a companyÆs ability to deliver value.This paper provides an overview of the key lessons learnt from ERMÆs experience of working with companies across a range of water sensitive industry sectors, in particular, the mining and oil and gas sectors, to develop and implement practical approaches to manage business critical water risk. These examples highlight the importance of managing water risk by linking technical and operational aspects of water management - with the longer term strategic and social license aspects. Four key ingredients were identified that are central to providing companies with a leading edge in the successful mitigation of water risk: understanding and evaluating water risk including the technical and operational aspects of water management, plus the longer term strategic and social aspects articulating a strong business case that prioritises water risks and their financial exposure to the organisation constructing a clear roadmap that practically links the water strategy objectives with on-the-ground implementation and action building capacity in the organisation to manage, engage and coordinate on water to mitigate risk.CITATION:Ringwood, K and Tang, A, 2013. Practical approaches to managing business critical water risk, in Proceedings Water in Mining 2013, pp 293-300 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By M Dean, M Nehring, P Knights, M S. Kizil

Integrated continuous mining techniques such as fully mobile in-pit crusher and conveyor (FMIPCC) systems offer inherent labour, energy and environmental benefits to deep pit metalliferous mines. However, before such systems become commonplace, a number of barriers must be overcome.This paper outlines a number of commonly perceived barriers to FMIPCC application, together with a number of suggested solutions. The paper advances a design approach for specifying FMIPCC systems for deep pit metalliferous applications. A novel FMIPCC configuration is advanced using a hydraulic excavator in backhoe configuration. Because of the requirement to minimise belt extensions, a mine planning approach is presented based on a series of parallel and radial belt conveyor moves.The FMIPCC system does not fully replace truck-shovel systems. In the proposed mine plan, sinking is undertaken with truck-shovel systems using a series of box cuts, whereas pit ‘widening’ activities are accomplished via the FMIPCC system. Because of inherent differences in mine sequencing, the net present value derived from the FMIPCC mine will differ markedly from that derived from traditional, nested-pit, truck-shovel mining approaches. Therefore, any comparison of the FMIPCC and truck-shovel approaches must take into account radically different mine planning approaches.CITATION:Dean, M, Knights, P, Kizil, M S and Nehring, M, 2015. Selection and planning of fully mobile in-pit crusher and conveyor systems for deep open pit metalliferous applications, in Proceedings Third International Future Mining Conference, pp 219–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By R A. Anand, N N. Viswanathan, M M. Pande

Slags are the most voluminous solid by-products generated in pyrometallurgical operations, and, as such, finding an application for these oxidic materials is pertinent to maintaining resource efficiency. In particular, pyrometallurgical copper production is associated with high slag rates, typically ranging from 2.2 to 3.0 tons of slag per ton produced copper, which necessitates slag valourisation. A possible application for these iron silicate slags is as supplementary cementitious materials (SCMs), which effectively lowers the CO2 emissions per ton of cementitious material. Although utilising iron silicate slags as SCMs has been studied in previous work, the scientific literature has limited data on the effect of composition on the inherent reactivity in cementitious systems. More specifically, no reports on the impact of FeO/SiO2 ratio have been presented in previous publications. Therefore, the present study aimed to isolate this parameter in a synthetic FeO-SiO2-Al2O3-CaO-MgO-Cr2O3 system. Since the amorphous content is a pertinent parameter for SCMs, a high-temperature confocal laser scanning microscope (HT-CLSM) was utilised to assess the crystallisation behaviour at continuous cooling conditions. Furthermore, high-temperature rheological experiments were conducted to measure the viscosities of the slags in relation to the crystallisation behaviour. The experiments showed that depolymerising the slag by increasing the FeO/SiO2 ratio generated a less viscous slag, which showed higher tendencies for crystallisation. Furthermore, experiments assessing the inherent reactivity as an SCM showed that depolymerising the slag by increasing the FeO/SiO2 ratio as the sole independent parameter generated an initially more reactive slag. However, replacing SiO2 with FeO was found to negatively affect the reactivity as measured over seven days within the tested compositional range.

Jun 19, 2024

By A Golsby

Both primary and secondary ventilation is important in underground mining. Secondary ventilation refers to the provision of ventilation to development ends, stopes and services facilities, which constitute secondary circuits tapped off the primary circuit or main through flow of air.An unbalanced primary and secondary combination can cause re-circulation, which is inefficient and potentially hazardous. These inefficiencies extend into operational and other considerations, such as power.Most cost justification analysis covers capital and physical consumables. These analyses are often not comprehensive or holistic. This case study is an example of ‘how to holistically justify’ a secondary ventilation circuit and optimise it to meet all stakeholder needs.This paper particularly addresses the following:how to account for all stakeholders in a secondary ventilation cost justificationthe secondary ventilation componentsthe cost justification outcomes and how to measure themsome of the sensitivitiesthe stakeholdershow to present the justification to meet the stakeholder needssecondary ventilation cost justification.CITATION:Golsby, A, 2015. Secondary ventilation as a value proposition – a case study, in Proceedings The Australian Mine Ventilation Conference, pp 49–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By D Phillpotts, S M. Mantsho, P Strobos

A challenge on many industrial flotation circuits is controlling concentrate mineral grades using measurements that are provided infrequently. The mineral grades in concentrate streams are a critical performance indicator in any industrial flotation circuit. Failure to achieve concentrate mineral grade targets has significant financial consequences on a flotation operation. A violation of a gangue mineral grade limits by the concentrator may also result in significant penalties. Online grade analysers which can provide reliable real-time grade measurements are essential for effective grade optimisation. The Blue Cube MQi analyser (by Blue Cube Systems) has recently come to prominence for its ability to rapidly determine mineral concentrate grades online and in-stream. This has provided excellent insight into the actual process dynamics in the flotation circuit, and hence enabled real-time control and optimisation of concentrate mineral grades. MintekÆs Measurement and Control division, specialising in advanced control solutions for mineral and metallurgical industries, has had the opportunity to link the FloatStar Grade-Recovery Optimiser to the measurements provided by the Blue Cube system at a nickel concentrator plant. The project initially focused on stabilising the final concentrate grade without directly accounting for nickel recovery. The site later procured additional Blue Cube MQi analysers, resulting in the expansion of the FloatStar Grade-Recovery Optimiser to incorporate recovery component in the performance. This site already had the FloatStar Grade-Recovery Optimiser for several years, but the original grade measurement device was unreliable and ultimately failed. The system was reactivated once the Blue Cube system was installed, replacing the old analyser.CITATION:Mantsho, S M, Phillpotts, D and Strobos, P, 2012. The implementation of FloatStar grade-recovery optimisation control solutions using Blue Cube online grade analysers on industrial flotation circuits, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 363-368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012