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By S R. Williams

There is a sense of geometallurgy being new; a new methodology for mining project development and improved operational strategy. One of the main challenges that any ænewÆ technology faces is a validation of the value and the need to produce case studies. However, producing case studies can often be problematic particularly given the long cycle from mineral deposit project, through feasibility and construction to stabilised operation of a mine.However, the roots of geometallurgy go back quite some time. Successful practices with geometallurgy can be seen from as early as the 1980s. Many times those practices were not called geometallurgy but something else and, in other cases, what can be seen are various components of the geometallurgical ævalue chainÆ.This paper will analyse a selection of published past practices from a geometallurgical perspective to demonstrate the value realised from the application of this methodology. The paper will then make some general comments on where this history of work in geometallurgy has lead us to and what are the challenges today for the geometallurgical effort.CITATION:S R Williams, 2013. A historical perspective of the application and success of geometallurgical methodologies, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 37-48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

Many types of micro-organisms inhabit iron ore deposits contributing to biogenic formation and conversion of iron oxides and associated minerals. Bacteria such as Paenibacillus polymyxa are capable of significantly altering the surface chemical behaviour of iron ore minerals such as haematite, alumina, calcite and silica. Differing mineral surface affinities of bacterial cells and metabolic products such as proteins and polysaccharides can be utilised to induce their flotation or flocculation. Mineral-specific bioreagents such as proteins are generated when bacteria are grown in the presence of haematite, alumina, calcite and silica. Alumina-grown bacterial cells and proteins separated from such cells were found to be capable of separating alumina from haematite. Biodegradation of iron ore flotation collectors such as amines and oleates can be effectively utilised to achieve environmental control in iron ore processing mills.

Jan 1, 2009

By R C. A Minnitt

The Witwatersrand Supergroup is host to the world’s largest gold deposits. The location, quantity, grade, continuity and other geological characteristics of a Mineral Resource are either known, estimated from specific geological evidence and knowledge, or interpreted from a well constrained and portrayed geological model. Establishing such a model is an integral part of the evaluation process in the Anglogold Ashanti (AGA) group, and is referred to as a Geoscience Business Model for the mining operations. The geological model established over the years has relied on detailed descriptions of the mineralisation, and understanding of the regional and local geology of the Witwatersrand sediments, in the West Wits and Free State goldfields. The processes of data collection in regard to underground stope and developing mapping, structural and sedimentological mapping, and the geological inputs to mine planning systems are described, together with aspects of drilling, sampling, grade control, and data management. Anglogold Ashanti’s Geoscience Department employs a complex and unique process to generate the Mineral Resource, including a 3D geological structure model of the orebodies which are usually highly faulted, and a robust mineralisation/facies model on which the decisions about domain boundaries are established. A Mineral Resource Inventory System (MRIS) has a dynamic graphic interface to the resource database that is used for compiling the resource statement. It is also used to determine the gold-called-for, as well as short and long-term planning. A unique estimation process using the extensive closely spaced stope face sampling database and the more widely spaced surface drilling information is used in combination in the Macro Co-Kriging estimation. The use of different support sizes in the C0-Kriging process is preceded by the equally unique ‘clusterisation’ and ‘acceptorisation’ procedures by which the data are quality controlled and assured prior to their use in the kriging process. The Mineral Resource and Ore Reserve estimates are classified according to the SAMREC code through a method that ensures that they are compliant, auditable, transparent and reconcilable with previous Mineral Resource and Ore Reserve statements.

Aug 22, 2011

By S Hapugoda, Y Tang, L Lu

The steel industry is one of the global leading CO2 emitters, accounting for approximately 7 per cent of global anthropogenic CO2 emissions. In 2022, the world produced 1878.5 Mt of crude steel. About 70.8 per cent of the world’s crude steel was produced by integrated steel mills through the blast furnace and basic oxygen furnace (BF-BOF) process, while the remainder was produced largely by mini mills using electrical arc furnaces (EAF). Compared with gas-based DRI and scrap-based EAF processes, the direct CO2 emissions from the BF-BOF process and the coal based DRI and EAF process are significantly more, as both the processes rely heavily on fossil fuels, such as coke and pulverised coal, to provide energy and reduce iron oxides. Hydrogen is very reactive and reduces iron oxides to metallic iron without generating CO2. Therefore, substitution of hydrogen for fossil fuels in these processes presents a good opportunity to significantly decarbonise the steel industry. This paper will first discuss the thermodynamic and kinetic characteristics of hydrogen and carbothermic reductions of iron oxides and then examine the behaviours of different ore types present in Australia iron ores during hydrogen reduction.

Sep 18, 2023

By Hargraves AJ

Pre-drainage experiments have been conduct- ed at Appin, Cook, John Darling, Leichhardt, Macquarie, Metropolitan and Moura No. 2 Collieries. Appin (550 m deep) experiences particular gas problems in development drivages, and the almost pure CH4 seam gas makes difficult tiro compliance with statutory maxima in intakes and returns. Patterns of 43 mm diameter drain- a,.;e holes drilled ahead and laterally into virgin coal have improved gas conditions in working places and have allowed tolerable advance rates. Cook, Leichhardt, Metropolitan and Moura No,. 2 Collieries have experienced gas and stress phenomena ranging from conical bursts less than one tonne to full scale instantan- -us outbursts of hundreds of tonnes with tens ,f thousands of cubic metres of seam gas. Gas ~Irainage experiments with patterns of holes up a,, 200 mm diameter have been undertaken with ;,;siness monitors on the coal to establish .lative effectiveness. Incremental flows into mg 43 mm diameter boreholes have investigated drainage patterns relative to length, and at comparative incremental flows have nlicated lowered permeability zones at stress ,.,utments. In some CO2 seam gas areas where iammability problems are reduced to perhaps ii, but where outbursts proneness is increased,

Jan 1, 1982

By J Kinal, P Steinier

A considerable volume of work exists in the literature examining the electrochemical interactions between grinding media and sulfide minerals. Broadly, most sulfide minerals are more noble than forged steel grinding media used during comminution, therefore a galvanic couple between the media and the sulfide mineral(s) exists, which increases the corrosion rate of the grinding media. The corrosion products of the grinding media, iron oxy-hydroxide species, invariably precipitate on to the surfaces of the sulfide minerals thereby affecting their floatability. This paper explores the science behind these corrosion reactions, and provides an explanation of their impact on the pulp chemistry of sulfide mineral slurries and subsequent flotation behaviour. A number of laboratory and plant case studies are used to illustrate the benefits of changing to a more inert grinding media.

Jan 1, 2005

By I Canbulat, J Oh, A Mcquillan, D Payne

This paper presents a new risk assessment tool for coal mine excavated slopes. This new empirical-statistical Slope Stability Assessment Methodology (SSAM) is intended for use by geotechnical engineers at both the design review and operational stages of a mine’s life to categorise the risk of an excavated coal mine slope. A likelihood of failure is determined using a new slope stability classification system for excavated coal mine slopes developed using a database of 119 intact and failed case studies sourced from open cut coal mines in Australia. Consequence of failure is based on slope height and stand-off distance at the toe of the excavated slope. Results are presented in a new risk matrix, with slope risk being divided into low, medium and high categories. The SSAM is put forward as a new risk assessment tool to assess the potential for, and consequence of, excavated coal mine slope failure. Unlike existing classification systems, assumptions about the likely failure mode or mechanism are not required. Instead, the SSAM applies an approach which compares the conditions present within the excavated slope face, with the known past performance of slopes with similar geotechnical and geometrical conditions, to estimate the slope’s propensity for failure. The SSAM is novel in that it considers the depositional history of strata in an excavated slope and how this sequence affects slope stability. It is further novel in that it does not require explicit measurements of intact rock, rock mass and/or defect strength to rapidly calculate a slope’s likelihood of failure and overall risk. Ratings can be determined entirely from visual observations of the excavated slope face. The new SSAM is designed to be used in conjunction with existing slope stability assessment tools. CITATION:Mcquillan, A, Canbulat, I, Payne, D and Oh, J, 2018. New risk assessment method for coal mine excavated slopes, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 473–495 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By J M. F Clout

Geological, textural and mineralogical classification of iron ores is routinely conducted by mine and exploration geologists on reverse circulation percussion, blasthole cone and bulk samples for grade control, defining ore and waste, determining lump:fines ratio and predicting downstream processing characteristics. Classification is based on physical hardness, colour, streak and other visual characteristics. However, logging is generally restricted to the five to 20 per cent of chips above about 2 mm. This means that most of the sample is too fine to be reliably logged for anything but colour or streak and the textural types must be inferred from other information. A recently developed software package called æRecognitionÆ allows automated identification and classification of iron ore textural types and gangue on a particle basis in polished section down to 0.01 mm using processed digital images. It is not designed to be used as a routine logging tool, but is applicable where higher definition is required at the resource evaluation stage on selected percussion, drill core or bulk samples. æRecognitionÆ processes data obtained after optical image analysis of fine iron ore samples. It contains several parts, like æRecognitionÆ, æCompositionÆ, æLiberation by Total IronÆ, æLiberation by PhasesÆ and æStatisticsÆ, which allow vast and diverse information to be obtained about the iron ore samples being studied. Identification and classification of the textural type of each particle is performed according to the CSIRO-Hamersley Iron Ore Group Classification Scheme. The recognition procedure encompasses a good knowledge of different ore types and a logical knowledge tree, managing fuzzy boundary problems and the potential for a few different ore types in the same particle to be considered. This new technology introduces strict criteria to make the process of identifying particles more objective. Automated recognition standardises the identification procedure and significantly saves time. It enables users without a strong background in mineralogy to perform accurate texture identification. The æRecognitionÆ package has a modern user-friendly interface and Word compatible output. The combination of all the features mentioned makes the package a convenient tool for detailed studies of fine iron ores.

Jan 1, 2005

By J E. Everett

An essential requirement of product quality control in the mining industry is to be able to reliably predict key quality properties of finished product from the data available before the extraction of the ore. From a production viewpoint, the unit of data collection is generally the input and output data set for each shift of crusher production, but could be any period where mine precrusher data can be reliably matched with product data.This paper demonstrates that linear regression models can be used to predict crush grades from blast grades, even where the crush material is blended from multiple sources or pits for each of which differing regression models might apply. The advantage of using increasingly complex regressions models to match the available data to give increasingly more powerful models is examined. The best model for any application will be a balance between required predictability, available data and the business’ tolerance for complex models.The regression modelling approach has several advantages over the more classic method of run-of-mine (ROM) crusher trials, which will be discussed.The models can use any predictor variable such as grade, geotype and in situ density provided the preextraction data set can be reliably matched with post-crusher data and is significant as a predictor. The models have been used extensively in the generation of the daily crusher plan with the aim of maintaining finished product grade. This approach has also been used associated with exploration drilling and long-term planning.It is acknowledged that there are inherent problems in fitting lump and fines grade to a linear model. However, these problems are minor when they are used for interpolation within the window spanned by the shift blend records used to produce the model. This paper discusses some of the issues limiting linear regression models in this application, and suggests methods enabling consistent models to be formulated

Sep 5, 2011

By L Nienaber

Mines, after becoming operational, often retain the same support and reinforcement designs developed in the feasibility study. These designs are conceived from limited drilling data and regional experience, thus having an empirical flavour. Empirical designs are perceived to be conservative, catering for a variety of failure mechanisms, which are not always present in mine development drives.This begs the question: If you were to invest in the necessary resources to obtain sufficient data and complete the required analyses for the different development drives in the mine, to engineer a support and reinforcement scheme with the capacity to match the demand of the rock mass, what is the difference in cost when comparing an empirical design to an engineered design?To answer this question, mine tunnels with different geometries and orientations, where detailed structural data was available, were selected for a comparative design exercise. Material cost, development cost, cycle time and professional fees for engineered and empirical designs were estimated. The outcome is summarised in the following paper that discusses the process followed and the results of the design comparison.

Mar 8, 2011

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 D K. Weatherley, A N. Mainza, I Govender, L M. Tavares, M S. Powell

It is understood that rocks do not instantaneously transport along a grinding mill and are consequently not perfectly mixed, but this is conveniently overlooked in mill modelling. A lack of understanding of the transport phenomenon and the difficulty of modelling realistic transport in a complex tumbling system, contribute to this. Visual observation of segregation in AG and SAG mills and measured lag time of mill response to changes in feed provide evidence of the influence of axial transport within mills. Incorporating this lag in dynamic models should underpin dynamic simulation of milling circuits for design and for model-based control. Limitations and errors in predicting the influence of increased power via mill length versus diameter, inability to predict pebble production, and a lack of the differential in residence time across rock sizes and competences, all contribute to inadequate design prediction that can be especially acute for large Autogenous mills. Examples of dramatically under – and overloaded pebble regrind circuits and the inability to predict pebble load in AG milling discouraging the application of this energy-efficient option, point to the need for predictive modelling of breakage by competence linked to transport through and out of mills. Incorporating progress in granular flow and mixing, coupled to computational advances enable models to be based on complex breakage and transport models at high spatial resolution. This allows mechanistic models to simulate thousands of times faster than real time, opening the door to more accurate mill design, including dynamics in process simulation and to live simulation for process control – all with advanced mechanistic models. The value of grasping this opportunity is not easily refuted.

Aug 24, 2022

The Bradford Process, Australian Patent No. 11253, has had considerable application in the treatment plants of Broken Hill mining companies, and is at present being used by the North Broken Hill Limited for the treatment of weathered slime accumulations.The "Mining and Scientific Press," of 28th September, 1918, describes the Bradford Process at Broken Hill, specially featuring its application to slime material at the Proprietary mine-the home of the process.The points then stressed for galena flotation were acidulated slime pulp (0.025 to 0.030% H2S04) at temperature 85° to 90° F. and suitable time contact, with 1.5 to 2 lb. of sodium hyposulphite (per ton on slime) to permit the released S02 to "wet" or depressthe blende mineral. Also 1.0 to 1.3 lb. of crude sulphur (per ton on slime) was burnt, to supply S02 for keeping the lead concentrate clean during flotation. Pulp density varied from 23 to 26% solids. Since 1918 the process has been simplified in its application.Acidity of circuit, temperature, and sodium hyposulphite have been dispensed with, and now the S02 is practically all obtained by burning crude sulphur. I The plant units now employed for control and absorption of S02 gas constitute the main advance made in process, and these, with other details, are fully explained in this paper.APPLICATION AT BROKEN HILL NORTHThe existing North Broken Hill Limited gravity mill commenced operations on 9th September, 1909.

Jan 1, 1929

By R Lachenicht, J Player, A Thompson, E Villaescusa

Kanowna Belle Gold Mine is a deep, high-stress, sublevel open stoping mine located near Kalgoorlie. Seismic activity during the development cycle presented problems, including concerns regarding the exposure of personnel. A number of seismic management systems were developed and tested to monitor seismicity and control the risk. It was recognised that a dynamically capable reinforcement and support system was required to be installed as part of the development cycle to reduce the risk of exposure of the underground workforce to uncontrolled movement of rock. The performance of a new Garford Dynamically capable bolt was measured in tests performed by the Western Australian School of Mines (WASM) at their Kalgoorlie Dynamic Test Facility. Detailed descriptions of the facility and data processing were reported by Player, Villaescusa and Thompson (2004) and Thompson, Villaescusa and Player (2004). The development of the Garford Dynamic bolt is described and dynamic testing results are presented and evaluated. This bolt was implemented in the mining cycle following the testing program; the observed performance is described and assessed in this paper.  

Jan 1, 2008

By E N. Sparg, O D. A Deuchar, F Needham

Decline shafts are an attractive option to both new and existing mining operations where there is a need to access an inclined orebody deposit via on-reef development so as to generate a return in the shortest possible time. There are many different technologies that are available to transport men, material and rock in incline shafts. This paper focuses on the applicability of two hoisting technologies for decline shafts, namely endless and direct rope systems. The pros and cons of each system are reviewed. A common concern with direct rope haulage systems is the possibility of generating slack rope during deceleration. This paper illustrates the issues involved in designing a system so as to avoid the possibility of slack rope. In conclusion, the key factors relevant to the selection of endless or direct rope haulages for a particular decline application are reviewed. The paper is a joint submission by FFE Minerals-Vecor and Qualter Hall UK.

Jan 1, 2005

By M I. Pownceby, N Karimian, J R. Manuel, M J. Peterson

The CSIRO ore classification scheme for Pilbara ores was used as a reference frame to target recognisable ore types/textures with potentially elevated phosphorus content for detailed analysis. Particles of each individual ore texture were separated from a Brockman high-P ore and each class was characterised using methods including XRF, XRD, EPMA and synchrotron-based XAS. Results were then correlated with optical microscopy and hand specimen identification to establish any relevant associated mineralogical phases and/or textures. This represents a more systematic approach to identification of high-P ore components based on particle and goethite type and texture. The information can then provide the basis for more targeted P-removal strategies factoring in the relationship between particle/ore texture and phosphorus deportment

Sep 18, 2023

By L Schürmann, R Kendall

Social licence to operate is becoming part of a mining company’s DNA in the same way as health and safety. Consequently, mining companies are receiving increasing pressure from their shareholders to ensure that they add enduring value to the local communities in which they operate. Apart from the shareholders, a company has responsibility to suppliers, customers, employees, the government and the community, which means under the social responsibility model they must be accountable to the other stakeholders. External and internal challenges in mining are increasing the difficulty and complexity of mines to operate. The external mining environment has a big impact on mining operations and is driving matters such as the focus on safety, responsible mining and resource management, sustainability issues, profitability and productivity. Considering this, it is expected that the widespread implementation of Environmental, Social and Governance (ESG) related practices across the mining industry in the next ten years will increase, not just for the big players but for juniors as well. Companies, investors, governments and insurers who fail to act on ESG matters are to likely face greater risks. Demonstrating leadership in ESG will ultimately become a differentiating factor and market participants have much to gain from embracing ESG stewardship as part of their competitive advantage. Stock Exchanges have an important role to play in advancing sustainability in the capital markets. It is for this reason that the Sustainable Stock Exchanges (SSE) initiative was founded to serve as a global platform for exploring how exchanges can enhance performance on ESG issues and encourage sustainable investment. The SSE initiative provides an effective platform for dialogue between the United Nations, stock exchanges, investors, companies and regulators in the mining industry. The paper will explain why ESG reporting is crucial for the survival of a mining company and how the lack of transparency could be detrimental to its public image and shareholder relations. The paper will also identify bodies that regulate ESG reporting, as well as the available tools that provide guidelines on reporting ESG matters. Key ESG reporting parameters (at a global scale) will also be highlighted.

Jun 22, 2022

By A R. Firth

The induration furnace for iron ore pellets was originally designed to process concentrates with high contents of magnetite. To support the use of haematite concentrates, internal fuel was added to the pellets in the form of ground coke breeze or anthracite. To ensure that the addition of coke breeze was not excessive, the ‘heat of magnetite equivalent’ or heat of magnetite equivalent (HME) relationship was developed, guaranteeing that the fi ring temperature requirements remained the same. However, this oversimplifi es the different reaction paths of magnetite and carbon in iron ore pellets. At fi ring temperatures, gas diffusion controlled reactions such as the combustion of coke, the calcination of carbonates and the reduction and oxidation of iron oxides can all occur in different parts of the pellet simultaneously. The interaction of these reactions produces a range of atmospheres across the diameter of the pellet that vary from oxidising at the pellet shell to reducing at the pellet core. Mathematical modelling and pellet fi ring experiments to preheat temperatures before quenching have shown that a higher proportion of coke relative to magnetite slows down the oxidation process, irrespective of temperature. A higher temperature, however, results in an increase in the rate of haematite reduction in the pellet core and a more reducing atmosphere, which could lead to different sintering rates in different parts of the pellet and shrinkage cracks forming. To observe these gas-solid reaction rates at a larger scale, the COREM pot grate has been updated with an additional oxygen analyser. This, along with other improvements, will allow better optimisation of straight-grate firing cycles for different pellet compositions.

Jul 11, 2011

By E Yurakov, D J. Ashelford, M I. Slate

The push for increasing coal production rates continues to place increasing demands on mine management to safely and effectively control seam gas. Gas drainage strategies applied vary in both effectiveness and form. Methods employed are a function of assessed risk, gas reservoir characteristics, surface and underground access, budgetary constraints and gas utilisation potential. With the aim of establishing and optimising the effectiveness and efficiency of gas drainage systems, Australian coal miners in cooperation with gas management specialists are embracing the use of gas reservoir simulators and gas emission models. This paper discusses the evolution of gas drainage practices in Australian underground coal mines and the role of gas reservoir assessment methods in optimising gas drainage systems and gas production forecasts.

Jan 1, 2005

By N McIntyre, M Edraki, K R. Jain

From the very early stages of a mining project, there is a requirement to predict the chemistry of potential drainages from various waste storage facilities. However, using relative masses to scale chemical loads measured by laboratory kinetic tests, such as humidity cells, to a full-scale mine waste facility will lead to concentration predictions that are unrealistically high for many dissolved constituents. Scaling factors developed by various procedures indicate that laboratory rates may range anywhere from two to eight times (Drever and Clow, 1995) to 100 to 1000 times faster than field rates (Malmstrom et al, 2000; Smith and Beckie, 2003; Ritchie, 1994). This contribution will use previous works and secondary data to discuss the significance of scale in water quality predictions. It will also present primary experimental geochemical and numerical data from a column leaching study on coal spoils to discuss potential applications of mesoscale leaching tests in bridging the gap between bench-top tests and field scale trials.

Aug 2, 2023