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By G F. Brent, S Hawke, M Rothery, P Dare-Bryan

Mine-to-mill studies have previously demonstrated downstream productivity benefits from relatively modest increases in blast energy, or powder factor. These increases have up to now been limited by safety and environmental constraints, since excessive blast energy can result in flyrock, unacceptable vibration, airblast and wall damage.Here, a new blasting method that overcomes these constraints is presented. For the first time it is possible to employ powder factors that are several fold higher than conventional blasting. Independent modelling has shown that such powder factors can potentially increase mill throughput by 20 to 40 per cent. The economic implications are substantial, both in terms of increasing production in existing operations and in consideration of capital and plant requirements for greenfield sites. In addition, mill electricity and grinding media consumption and their associated costs and energy and emissions penalties can be reduced.This method represents a step-change in blasting practices. It involves a novel design utilising dual blast layers within a single blast event, all initiated with state-of-the art electronic blasting systems. The energies in the lower layer can be as high as five times the standard energies, providing for intense fragmentation of the ore. Results from blast models have been confirmed in field trials of the method.Open cut gold mining, in particular, stands to benefit from this method. As gold grades decline, milling costs and throughput increasingly become constraints on production that can be alleviated with this new method. Additionally, it opens possibilities for improved recovery. Blast modelling studies show that dilution of gold ore within the blast can be managed with the new method. Furthermore, it has been shown that vibration from the new method is actually lower than from conventional blasting, allowing the use of the technique in proximity to mine highwalls and other key infrastructure such as underground orepasses.It is concluded that this new method could substantially increase gold mine production and profitability while reducing overall energy consumption and associated emissions.CITATION:Brent, G F, Dare-Bryan, P, Hawke, S and Rothery, M, 2013. Ultra-high-intensity blasting - a new paradigm in mining, in Proceedings World Gold 2013 , pp 395-400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By A Tolley

Bauxite residue or ‘red mud’ is a by-product of the Bayer Process, the primary process of alumina refining. Due to its high alkalinity and variable composition, its storage and disposal poses high environmental risks to water sources, surrounding ecosystems and human health. The high alkalinity (pH 12–13) is a significant factor in its classification as hazardous waste; to mitigate this, Australian refineries have integrated neutralisation processes into bauxite refining. Both sea water and carbon dioxide neutralisation processes are applicable. Multiple studies have demonstrated pH reduction from 12–13 to 7–10, depending on the method. The key advantages of CO2 neutralisation are that it allows for carbon sequestration and is more effective when utilised as a pre-treatment for recovery of metals, while sea water neutralisation is more established and has been integrated into two Australian refineries. This paper proposes the application of the bacteria Exiguobacterium oxidotolerans for bioleaching of iron from hematite in bauxite residue. The genus Exiguobacterium is characterised by its high levels of adaptability, halotolerance and alkaliphilic nature. E. oxidotolerans is successful at eluting Fe2+ from hematite via reductive dissolution, which complexes with oxalic acid produced during metabolism. This aquatic bacterium presents a novel process pathway for iron elution due to direct interaction of E. oxidotolerans with hematite via the cell membrane and operates within the pH range of neutralised red mud. The proposed mechanism is extracellular electron transfer, a microbial metabolic process where electron transfer is facilitated between bacterial cells and extracellular material. Currently this is being investigated for promotion of seaweed growth in coastal environments as soluble iron aids and fortifies colonies. This has potential downstream applications for cleaner iron and steel production. While theoretical, this paper explores the neutralisation, bioleaching and application of the Fe(II)- and Fe(III)-oxalate complexes formed.

Sep 18, 2023

By DJ McKEE

Process control emerged in the mid-1960s as a new and exciting method of improving the performance of mineral processing operations. The early Australian developments, principally in Broken Hill and Mount Isa, were based on pioneering work in instrumentation, the availability of small digital computers and a particularly effective partnership between companies with technological foresight and University and CSIRO research groups. Initial progress was rapid and within ten years many plants were committed to process control. Process monitoring is now routine and most circuits have some level of control. However, few plants have comprehensive optimising control systems as the difficulty of developing control strategies which can cope with the wide variety of conditions encountered in most mineral plants has been fully appreciated. This paper summarises past experience and assesses the degree of application of different forms of process control in metallurgical plants. Barriers to the effective utilisation of opt rising control are identified and some suggestions for advancing the application of control are made.

Jan 1, 1992

Geological hazards such as faulting, basement ridges, and zones of "thin" (

Jan 1, 1998

By M Frenzel

At the last MassMin Conference in Sudbury, Caterpillar’s vision of a continuous mining concept for block caving operations was presented on the background of global raw material demand and its continuous increase. By analysing today’s structure of mining processes in block caving, the paper (Krings, Steinberg and Frenzel, 2012) highlighted the main bottlenecks in the process chain and identified conceptual solutions by help of a case study. The main focus was the paradigm shift from discontinuous batch type operation to a continuous mining process of the blocks.In 2016, the strategic vision has taken major strides forwards and remote continuous operation has become a reality. Caterpillar’s continuous operation system – the Rock Flow system – was successfully installed in Codelco’s Andina mine and start of operation is scheduled in the first half of 2016.Based on continuous product developments, this paper sets the focus on two main aspects of continuous mining. First, field experiences of the Rock Flow system will be shared, highlighting the Andina project course from system installation, to commissioning and successful system start. The second aspect concentrates on the system and mine layout as discussed in the case study scenario in MassMin 2012 (Krings, Steinberg and Frenzel, 2012).Based on Caterpillar`s continuous product development, the Rock Flow system set-up and panel design were modified for a general roadway design and drawpoint layout. The new design allows an optimised use in block preparation phase (spreading) and full production phase (reaping), operating a fleet of load-haul-dumps (LHDs) and Rock Flow systems. The combined use of the two technologies optimises the mining process in every stage of block life and significantly increases the performance of the continuous block caving operation in the production panel to pave the road for the next generation of super caves.CITATION:Frenzel, M, 2016. New continuous production system in block cave mining – the rock flow system, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 543–548 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A von Johannides, G J. van Hout, L F

In the past various systems have been used to plan the extraction of ore from block cave operations. These systems have varied from rather sophisticated models with empirical ægravity flowÆ rules applied to the very rudimentary models where only the recorded mined tonnageÆs have been accounted for against the available resource. The normal requirement of these models has been to only plan the movement of ground through the drawpoints. Little cognisance has been taken of the other parameters that affect the total mining operations. The intended purpose of the linear program planning system is to not only include the management, resource availability and geotechnical constraints, but to also include the mining rules. The paper will discuss the various constraints that have been considered, and attempt to illustrate where the system better serves the production system than previous ones. A brief technical discussion on the linear programming system is included.

Jan 1, 2000

This talk was delivered in Kalgoorlie in April this year, to the Kalgoorlie Branch of The Institution of Engineers, Australia. We believe it is of such interest to members of our Institute and readers of this publication we believe it important to extend the audience who have the opportunity to read it. An edited version follows:"Why should we be so concerned about Mining Related Education; after all is said and done, the mining industry is not a great employer of persons?"The mining industry is capital rather than labour intensive. It employs only 2.7 per cent of the national workforce. However; the minerals industry is Australia's major exporter accounting for over 40 per cent of the nation's total export of goods.In Western Australia the value of minerals production in 1985 was about $5,000 million and consequently mineral exports accounted for about 53 per cent of the total value of overseas exports from the State. The diversity of the mining industry is also worthy of mention and produces iron ore, alumina, gold, nickel and mineral sands. That apart, our potential to become a major producer of diamonds, rare earths and petroleum products is considerable, not to mention base metals (copper, lead and zinc) and uranium.Our mining industry is of national importance and contributes in excess of 30 per cent of the total value of Australian overseas trade. Although the mining ind ustry does not employ many people, the people it employs contribute very much more, per capita, to the wealth of the nation than do employees in any other sector of our economy.No-one would deny that during the 20th century Australians have depended on the export earnings from the sale of relatively unprocessed agricultural products and more recently the sale of relatively unprocessed minerals for their standard of living.Not surprisingly, therefore, our economy is highly vulnerable to unstable world commodity market prices.The slump in trade we are currently experiencing (in first quarter 1987-Edition) was brought about by the over supply of the raw materials we produce. However, the recent downturn in world market prices is more serious than previous slumps because in part it is due to technological advances 'in other countries which could have a permanent effect on the world trade of primary products.

Jan 1, 1987

The value of Australia's education services exports increased to over $15 billion dollars in 2009, placing education as the third overall export earner behind coal and iron ore; however there are concerns over the impact of emerging policies on the future of both the industry and the provision of mining education. Policies have impacts on the growing number of international rankings (or league tables) of mining jurisdictions and universities. A high position in such rankings might be used as a measure of perceived quality with benefit to those at the top and to the detriment to those lower down.    Top performing companies in the relatively new domain of sustainability have been shown to achieve better financial performance than their industry competitors, assisting them in attracting top quality committed staff, hence positioning themselves well for the future. The world's mining companies, jurisdictions and universities are now ranked with results in the public domain. It is argued as to the validity of the data or perceptions used in such rankings, but there is no doubt they are influential in determining the flow of dollars around the globe. By investing your pension fund assets in the shares of the top performing companies, by placing your exploration dollars in a country at the top of such a list of attractive jurisdictions, attending or recruiting from a University at the top of the rankings - risk must surely be reduced?   While savings and risk reduction can undoubtedly result from the introduction of new technologies developed through appropriate R&D (the other core activity of a university), the maintenance of a very high level of exploration and production performance through dedicated highly skilled staff every hour of every day quietly improves financial performance, while avoiding safety, environmental and/or community incidents (ie protects the 'triple bottom line'). As always risk reduction comes down to enabling quality people to do a quality job - through the actions of such people we can sustain the global mining industry and secure our social license to operate. However, there is global concern over where the numbers of such people, including those with the recently required skills in sustainability, are going to come from.   This presentation will discuss some of the complexity and interactions involved in the development of such rankings, the dangers inherent in their simple acceptance and use, plus indicate some of the directions mining educators might take to sustain and increase the supply of quality graduates to the global mining industry. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Jun 1, 2010

By G E. Holt

Active EM subsurface imaging is a proprietary technique developed by Marschall Acoustics Instruments Pty Limited (MAI) to image subsurface features at depths useful for the mining industry. Similar in field operations to high resolution seismic surveying, the Active EM technique employs electromagnetic energy rather than elastic wave energy. Received backscattered energy in the Active EM technique is thus due to differences and contrasts in electromagnetic permeability and permittivity in the subsurface, analogous to LamTÆs constants in elastic wave imaging. Carrying the analogy to seismic imaging even further, the Active EM method employs high power transmissions of very wide-band coded signals of a controlled polarisation. Likewise, the array pattern and polarisation of the receiving transducers is also tightly controlled. Thus, in a certain mathematical sense, Active EM is the electromagnetic equivalent of high power high resolution vibroseis seismic surveying. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Contemporary approaches to safety management appear to be failing short of meeting its mark in improving mine safety. This is evidenced by the high workers compensation, high incidence rates and fatalities. Evidence from high-risk and complex organisations points towards safety culture as being important in improving site safety. In more recent years resilience engineering has been touted as a new and innovative way of managing safety. This paper reviews and synthesises previous literature on safety culture and resilience engineering. It then highlights methods that can be used to measure safety culture and resilience engineering, and explores similarities and differences between complex organisations and gold mining to identify opportunities for more innovative approaches to improving safety in gold mining operations through safety culture and resilience engineering.

Aug 1, 2010

By H Zhang, S Li, J Song, Z Lv

In this paper, a method for extracting and refining metallic molybdenum using low-temperature ZnCl2- NaCl-KCl molten salt was proposed. The electrochemical behaviour of molybdenum ions in ZnCl2- NaCl-KCl molten salt was investigated in detail, and pure metallic molybdenum was collected on the cathode. The reduction and diffusion processes of Mo(V) ions in ZnCl2-NaCl-KCl molten salt were determined through a series of electrochemical methods. The diffusion coefficients and nucleation modes of Mo(V) ions were also studied, and electrolysis was conducted for a prolonged period at a constant current density. The results indicated that the electrode reduction of Mo(V) ions in ZnCl2- NaCl-KCl molten salt proceeds through a three-step reaction: Mo(V) → Mo(IV) → Mo(III) → Mo at 250°C. The Mo(V) → Mo(IV) reaction was reversible and diffusion-controlled, with a Mo(V) diffusion coefficient of 6.02 × 10-6 cm2 s-1. Additionally, the nucleation mode of Mo(V) ions was instantaneous nucleation. The products electro-deposited were confirmed of metallic molybdenum with a particle size of less than 1 μm.

Aug 21, 2024

By Z Gao, D Liao, W Sun, S G. Pooley, J Wang, Z Shi, G Jing, S Ren, Q Chen

Yuanjing processing plant is a scheelite and wolframite plant in southern China. Water shortages and recent environmental regulations mean that the plant must reuse the wastewater that comes from the mining operation. This paper describes the efforts to reuse the mining and ore washing wastewater (MOW) in the processing plant. Initial attempts to reuse the MOW in the strong magnetic separation were unsuccessful because the magnetic media pack was seriously fouled by the micro-fine precipitate generated. The focus changed to reuse the MOW in the scheelite flotation circuit, which includes one roughing, one cleaning and three scavenging steps. Laboratory batch tests showed this would likely be successful because using MOW reliably improved the flotation performance in the laboratory tests. Then a 20 day industrial trial was run in the plant. The trial was very successful with the enrichment ratio of WO3 increasing from 17.4 to 23.6, while the recovery remained around 79.2 per cent. The industrial trial was so successful the company immediately adopted the new scheme, which has remained in use ever since. This technical solution not only alleviated serious water shortages, and satisfied environmental regulations but also improved the plant performance.

Aug 24, 2022

By K Saito, M Hasegawa

Removing sulfur and phosphorus from molten iron can be expressed by the following reactions, respectively. [S]Fe + (O2-)slag = (S2-)slag + [O]Fe [P]Fe + (3/2) (O2-)slag + (5/2) (FeO)slag = (PO43-)slag + (5/2) Fe(liquid) These equations indicate that desulfurisation and dephosphorisation have opposite oxygen potential conditions. If a small amount of desulfurisation slag not removed is carried over to dephosphorisation process, the reaction of sulfur mentioned above proceeds toward left hand resulting in increasing sulfur content in molten iron. For better understanding of such re-sulfurisation reaction in hot metal pre-treatments, the present study aimed at evaluating the effect of iron oxide on the sulfur distribution ratio between slag and hot metal. To measure sulfide capacities and FeO activities simultaneously at temperatures below the melting point of pure iron, CaO-SiO2-FeO and CaO-Al2O3-FeO ternary molten slags were brought into equilibria with copper-iron-sulfur liquid alloys, and the equilibrium oxygen partial pressures were determined with an electrochemical technique involving the stabilised zirconia solid electrolyte. The experimental results showed that the sulfide capacity increased with an increase in FeO content, and this trend was consistent with the fact that FeO was basic. Although the addition of FeO raised the FeO activity and oxygen potential, the calculated value for sulfur distribution ratio between slag and hot metal increased with increasing FeO content.

Jun 19, 2024

My forebears migrated to South Australia in the 1830s, 1840s and 1850s. All of them were literate but, because they moved about South Australia looking for work, family papers have become scat- tered and I am left with a few fragments. Some years ago I was intrigued to find among my fath- er's books a frontispiece in an old Anglican Book of Lessons. As can be seen Joseph, a mining smith, was also a Freemason. Thus my interest was aroused. I know some- thing of modern day mining communities in South Australia and wondered what they were like 100 or more years ago.

Jan 1, 1987

By Baker G

The detailed mineral composition of the lead-zinc ores at Captain's Flat was first studied in 1942 (Edwards, 1943).At that time the workings did not extend far below the 750ft. level. Since then development has been extended to the 1,390ft. level, and -at the request of the management of Lake George Mines Ltd., an examination of the ore from the deeper levels has been made as part of the research programme of the Mineragraphic Section of the Commonwealth Scientific and Industrial Research Organization.This account is. based on that examination (Mineragraphic Rept. No. ,537, C.S.I.R.O.)GENERAL GEOLOGYThe geology of the Lake George Mines has been described briefly in The Geology of Australian Ore Deposits (1953), and in much greater detail in an unpublished report by K. Glasson (1952). The area consists of fossiliferous Upper Ordovician sediments overlain by volcanics (Kohinoor VoJcanics), and by fossiliferous Silurian sediments. The volcanies comprise a series of· flows ranging in' composition from dacite to rhyolite, with interbedded tuft's and shale lenses.The region has been strongly folded. The regional strike is from 340° to 355°, and dips are from 75°W. to 75°E, A major syncline, pitching 200 N., occupies the centre of the area. The Kohinoor Volcanic'l outcrop as two bands which represent the east and west limbs of this syncline.The Volcanks in the western limb, with whIch the orebodies are associated, are more strongly sheared than those in the eastern limb.

Jan 1, 1953

By B Bradák, D Asahina, S Saydam, S Akdag

Human exploration of Mars has been on the horizon of scientific goals for decades now, and as part of the objectives of human missions to various planets, one of the possible goals is opening new economic frontiers by the potential extraction and utilisation of resources, eg mining minerals and using surface regolith (Neukart, 2024). A comprehensive understanding of surface morphology, lithostratigraphy, basic structural geology, and civil engineering technology is essential to conduct mining operations for resource extraction on extraterrestrial planets. For instance, proper assessment of the risks associated with excavation and infrastructure construction under unique environments such as low gravity, surface irregularities, and the presence of regolith is fundamental. Such knowledge has been accumulated through satellite imagery and numerical topographic data using remote sensing technology, as well as seismic surveys by the on-site lander (Knapmeyer- Edrun et al, 2021; Banerdt et al, 2020; Giardini et al, 2020). Recent studies show that Marsquakes could be caused by the release of strain energy generated by the contraction of Mars. In particular, Marsquakes occur around the graben where many faults exist and form regularly spaced patterns. This implies that Marsquakes occur when the stress field of the Martian crust is an extension condition, and normal faults appear on the surface. In this study, we focus on so-called graben structures, one of Mars’s common tectonic structures (Plescia, 1991; Banerdt et al, 1992; Hoogenboom Hagen, 2014). The study aims to provide additional information about the tectonic environment during the formation of such features and, in addition, the internal mechanical-rheological structure of Mars, revealed by the geometrical pattern of faults modelled and simulated in a laboratory environment.

Sep 1, 2024

By P Christen, D R. Ashley, G R. Power

The Ernest Henry Mine is currently a copper-gold open pit operation situated in north-west Queensland, Australia. It is owned and operated by Xstrata Copper with a current throughput of 11 million tonnes per annum; however, open pit operations are scheduled to cease in late 2011. The deposit dips at approximately 45¦ and extends for at least another 400 vertical metres below the final 530 m deep pit design. Resource drilling from 2002 until mid 2008 has enabled an Indicated Mineral Resource to be established to 1000 m below surface. Scoping and prefeasibility studies (PFS) have been completed toward determining if this resource is suitable for underground mining and a feasibility study is currently progressing with a sublevel caving (SLC) concept. This paper briefly describes the process by which the SLC method was selected, conclusions regarding the non-selected methods, and then discusses the optimisation process used to derive the mining plan. The key optimisation parameters include the production drive spacing, level spacing, draw strategy, cut-off grade and production rate. Key risks will then be assessed and economic sensitivities studied. Final sensitivities will use Monte Carlo simulations to improve the transparency of the projectÆs risk profile. The feasibility study (FS) began in March 2008 and this paper describes the main optimisation steps at the time of writing and outlines the plan for study completion through to March 2009.

Jan 1, 2009

By J Zhou, L Crompton, K P. Galvin, J L. Sutherland, C P. Lowes, C Bezuidenhout, J Bijzet

Platinum Group Metal (PGM) bearing ores from the Upper Group 2 (UG2) reef often contain significant concentrations of chromite which can potentially be upgraded to produce a saleable product. A common approach is to implement gravity separation on the PGM flotation circuit tailings. However, where the particle size range of interest is broad and the lower size limit ultra-fine, the challenge is how to maximise the recovery at a saleable product grade without compromising throughput. This study was concerned with the performance of a REFLUX™ Classifier for beneficiation of a PGM bearing chromite ore and the benefits of size classification. The sample had a nominal top size of 0.5 mm and was processed over the complete size range and in two discrete size classes following classification at 106 µm. The primary goal was to produce a concentrate exceeding 40 wt. per cent Cr2O3, ideally approaching 42 wt. per cent Cr2O3, with minimal PGM losses above 106 µm. A major challenge was to process at the required solids throughput in a single stage with the feed pulp density constrained to a nominal upper limit of 30 wt. per cent solids. It was found that varying the controller density set point of the REFLUX™ Classifier produced strong control of the product grade. Products as high as 41.1 wt. per cent Cr2O3 were produced at 78.6 per cent recovery for the +106 µm material, while in the −106 µm portion the product grade was as high as 41.4 wt. per cent Cr2O3 at 83.2 per cent recovery. Processing the feed in discrete size classes enabled the volumetric feed and fluidisation rates to be optimised for a given application; hence, superior performance was achieved at the finer sizes. This work has demonstrated the value in considering feed preparation as well as technology selection in developing a robust process solution.

Aug 24, 2022

By J Beniscelli

Some words to honour Pedro:Pedro was among the few persons with a very high level in geology modelling, resource and reserve estimation, geometallurgy development, sampling theory applications and a deep understanding of the mining industry needs. He had brilliant ideas about new developments on economic geology. He was always looking at the long-term and proposed challenging questions a decade in advance on their solution.The fundamental aim of geometallurgy is to add economic value to the mining of mine resources by timely providing information and knowledge about the relevant metallurgical variables represented by their space models. In this manner, geometallurgy allows obtaining the optimal design of a project, mitigating processing risks, optimising and supporting production plans and identifying and assessing mining business opportunities.This paper describes the conceptual framework and geometallurgical definitions and some of Codelco’s experience during the last 15 years.

Sep 5, 2011

Classification within the Inferred Resource category is based on geological judgement and the balance of extrapolation versus interpolation that the Competent Person is prepared to accept. These resources are typically drilled at spacings well in excess of the geostatistical range and at a density that is non-uniform. In many cases, a substantial proportion of the available data will be historical, and should be considered with more recent data sources. The provision of a robust geological model will increase the confidence in any resource estimate, and should be viewed as a critical component. The definition of Inferred Resources is of great importance to vein gold projects, since Indicated and Measured Resources generally require costly underground development for delineation. Indeed, many gold vein operations possess substantial quantities of Inferred Resources (>75 per cent) in their resource inventory both at project start-up and during production. This contribution explores a number of the key issues when using the Inferred Resource category and presents four recent case studies.

Jan 1, 2006