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Fine Gravity Separation in the Reflux Classifier, Exploiting a High Shear Rate, Laminar Flow Mechanism The Reflux Classifier is used in the gravity separation of particles over a broad range of particle sizes. The device consists of a fluidised bed zone, with a system of parallel inclined channels above. The inclined channels provide a significant hydraulic advantage over conventional fluidised beds via the so-called Boycott Effect (Boycott, 1920). This paper describes a new advance in fine gravity separation based on the high shear rate and laminar flow profile that arises when closely spaced inclined channels are deployed. As reported recently (Galvin et al, 2009a), a powerful density based separation mechanism develops from this arrangement, suppressing the effects of particle size. In this paper we focus on two areas, firstly the application of the separator in the laboratory for batch fractionation of particles of varying size and density to determine the grade recovery curve and hence the liberation, and secondly the step change in separation performance achieved on a continuous steady state basis when closely spaced inclined channels are used. The variation in the separation density with particle size decreases significantly, and the Ecarte Probable Error (Ep) remains at low levels over a broad size range.

Sep 13, 2010

By K Rau

The overall success of a mining operation is directly impacted by the reliability and availability of mining equipment. Heavy-duty vehicles such as excavators and haul trucks are used for conveying of bulk material and improving such assets’ availability helps reduce costs, increase throughputs and improve safety (Ravande, 2022). If a mining operation’s key performance indicators (KPIs) are tied to operational performance, then overall equipment effectiveness (OEE) is an essential metric to track progress and to identify areas of improvement.

Sep 1, 2024

By H Esterhuizen, W Hartman

Rockfalls or significant deterioration of mine openings can have significant safety and financial impacts for mining operations. The failure of drives in underground mines sometimes highlight deficiencies in the mine risk management systems in detecting geotechnical hazards and to prevent events that can have significant impact. Consequences from these failures includes fatalities, injuries, loss of revenue, additional cost, and potentially a loss in Ore Reserves. Where the impacts are severe, it also affects families and communities linked to the operation. The assessment of underground excavations requires consideration of the full range and spectrum of geotechnical hazards, design aspects, ground support, layouts and sequences. Where the assessment of these are insufficient or incorrect, it can result in drive failures. Care must be taken that meeting production targets and personnel pressures do not result in a situation where production take preference over a proper risk-based assessment of the drives to be mined. The risk management approach is now widely accepted in the mining industry for the control and management of risks in underground mines. Codes of Practices (COP’s), Ground Control Management Plans (GCMP), Principal Hazard Management Plans (PHMP’s) and technical guidance documents has become the norm for describing the mines main hazards, risk levels and intimating controls for safe passage of vehicles and mine personnel. However, where there is a disconnect between these documents and what is actually being done at the mine site, the COP’s and/or Management Plans become ineffective (or vice versa). This disconnect may occur due to the actual content of these documents, a lack of resources, or a lack of understanding about the implementation. There is therefore a need for sites to have a documented and implemented risk-based approach for assessing underground mine development. This approach or system needs to identify all hazards and other factors affecting mine development stability early on in the design process, and outline the risk classification and controls required. This paper presents an amalgamation and modification of previous processes for a Geotechnical Risk Management System for Underground Mine Development. CITATION:Hartman, W and Esterhuizen, H, 2018. A geotechnical risk assessment tool for underground mine drives, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 235–253 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By J Charbucinski

Commonwealth Scientific and Industrial Research Organisation (CSIRO), Exploration and Mining, has developed nuclear spectrometric techniques for borehole logging. The paper reviews the latest developments of this technology for the metalliferous mining industries. The SIROLOG logging system developed by CSIRO Exploration and Mining has been commercialised and is available to the mining industry.

Jan 1, 2000

By M Ireland

Extensive use of diesel-powered mobile equipment in modern mines for materials handling, such as load-haul-dump machines, constitute a significant source of heat, exhaust gases and diesel particulate matter. Provision of sufficient quantities of fresh, cool air are required to remove such atmospheric contaminants from the environment for miners, particularly at depths where ventilation constraints and associated operating costs have an increasingly adverse impact. An alternative solution to diesel equipment to combat economic, environmental, social and health challenges, are battery electric vehicles (BEV), with the potential to expand production and substantially reduce ventilation and cooling demand, subsequently reducing operating costs. In this context, this paper focuses on the introduction of a battery electric loader to a diesel fleet at one of the deepest underground mines in Australia, the CSA Mine, a high-grade copper operation in Cobar, New South Wales. Analysis of a trial battery electric loader compared to existing diesel machines is performed with regards to infrastructure, technical and operational issues. Key benefits of battery electric vehicles over conventional diesel-powered vehicles are discussed, including lower energy consumption and greater efficiency, reduction of emissions and heat, reduced need for ventilation and lower operating costs. Challenges of introducing BEVs into an operation, along with the results from the comparative study are addressed under impacts to energy consumption, equipment selection, effects on ventilation and cooling, mine design and economic viability for future fleet implementation scenarios whilst meeting production targets.

Mar 29, 2023

By A Paz, H Lehto, M +stholm, I Roitto

Nowadays, the demand for a finer grind in minerals processing has set new challenges within the industry, particularly for grinding technology. Apart from a finer grind, energy efficiency is also a key driver in optimising comminution technology.Stirred milling technology, already proven in many other industries, delivers a modern, sophisticated, flexible and energy efficient grinding solution for fine and ultra fine grinding in minerals processing. Fine grinding technology is utilised particularly in concentrate regrinding to complete the liberation of valuable minerals after the first stage of concentration. Maintaining the correct particle and particle size distribution of the regrind product is crucial for downstream process performance. Stirred milling technology offers the unique possibility for online control and optimisation of the regrind product particle size. This paper describes the basis of this online control possibility and discusses the implementation of stirred milling technology in minerals processing, particularly in regrinding applications. The paper will also outline management and control of fluctuations in feed rate tonnages as well as particle size fluctuations in concentrate regrinding.CITATION:Roitto, I, Lehto, H, Paz, A and +stholm, M, 2013. Stirred milling technology - A new concept in fine grinding, in Proceedings MetPlant 2013 , pp 190-201 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

Project delivery in our current market is not as efficient as it could be. Industry at large (both client and consultant), is diligently following the engineer, procure, construct, manage (EPCM) or engineer, procure, construct (EPC) delivery models and not necessarily appreciating the underlying principles that make them the effective tools they were to start with. We often misinterpret project management with EPCM and end up with a literal and superficial interpretation instead of the disciplined risk reduction and business value capture exercise it is intended to be. One of these underlying principles is the project team as resource or commodity depending on which perspective we follow. Some of us understand this principle only too well and succumb to the temptation to take advantage of the imbalance in the understanding of EPCM by selling bodies and hours. Value and return on investment do not always come into the equation. The latecomers and aspirants are struggling with this as a barrier of entry into this lucrative market, since as we all know - people as commodity was becoming and still is a scarce resource. Clients are also waking up and asking why 1000 engineers on the floor are better than 100, when engineering design in all aspects of industry, new technology aside, is mature. Why is it that we start with a clean sheet of paper with every project or that neighbours in the same industry segment and location just happen to have completely unique conditions and circumstances that require totally original design (Local conditions aside)? The answers to this question appear when we explore the role of the project team and how it is structured. We will need to investigate team culture and levers for success. Then we will formulate a business case for a team to be able to follow traditional project management practices with EPCM delivery models but yet end up with an alternative look, feel and result. An outcome where more input is not necessarily better and the client and consultant both are aligned with success measured in dollars and a win-win outcome for both parties.

Jan 1, 2009

A massive cobalt-containing pyrite orebody occurs in banded albite-quartz-biotite rocks at Thackaringa, some 30 km SW of Broken Hill. Because of the world-wide shortage of cobalt during the late 1970s, serious consideration was given to the development of a suitable flow-sheet to recover the cobalt from this ore. Details of a pressure leaching process in which more than 90 per cent of the cobalt is extracted from a pyrite concentrate are presented.

Jan 1, 1983

Conservation and environmental issues are raising their profile with respect to both demand restraint and electricity supply options. In New Zealand, conservation pressures and energy efficiency need to be seen in relation to the supply system currently in place which has capacity for economic supply of electricity in quantities substantially in excess of the current market. Consequently, energy efficiency and conservation need to be interpreted in relation to the supply system as well as in relation to end use. The relationship between the environment and conservation is strongest when new generation is required. New Zealand's electricity supply system consists of a large proportion of hydro production and this has significant environmental benefits when considered in relation to concerns of global wanning and the greenhouse effect. However, environmental trade-offs in supply options need to take account of both the efficiency of electricity end use, the trade-off between hydro and thermal generation and the inter-regional effects of shifting development options from one region to another. The Electricity Corporation has a high level of consciousness with respect to environmental and conservation issues and this paper demonstrates its own moves to maximise energy efficiency and illustrate the environmental trade-offs for supply.

Jan 1, 1990

An investigation into the causes of variable sulphur content in blast furnace metal produced at No. 4 blast furnace at the Port Kembla works of Australian Iron and Steel Pty. Ltd. was carried out. Theprogramme included an extended and detailed experimental study of a great number of the operating variables of the furnace, on a cast-bycast or four-hourly basis, over fourteen days.Possible causes of the variation were found in irregular operation due to sinter variability, and it was also clearly shown that slag conditions were most important in controlling sulphur contents of pigiron. Some decrease in sulphur variability was achieved, arising partly from this investigation, and it is hoped to try magnesia additions to modify slag conditions for better desulphurizing.INTRODUCTIONSulphur in pig iron is a problem common to many blast furnace operators throughout the world, but the direct causes and means of overcoming them are functions of the available raw materials, and are hence more particular to each plant and its operating practice. Sulphur in hot metal influences the steel-making operations, the rolling operations and the quality of the finished steel. The main problem associated with high sulphur in steel is "hot shortness", which leads to cracking of ingots and billets in rolling, to poor surface finish and to poor welding properties in the finished steel. On the other hand, sulphur is sometimes a desired additive to steel in order to promote free machining properties.Normal means of controlling sulphur A small degree of control of sulphur in steel is available to open hearth operators by alteration of slag volumes and basicity, but any large degree' of sulphur elimination is...

Jan 1, 1961

Determination of Porosity and its Influence on Specific Surface

Sep 13, 2010

Blasting is an essential component of most mining operations, and is used to reduce the rock mass to a workable size distribution, as well as to create stable openings and pit walls. Frequently, there is little difference between the designs of blasts to achieve these two functions, though more advanced operations have developed different designs for these very different functions. To assist in the appreciation of how blasting practices can impact on the stability of rock openings and pit excavations, this paper reviews the role of high pressure explosion gases on final block stability. It is assumed that the stability of all surface and underground excavations are, to a greater or lesser extent, controlled by the interaction between discrete rock blocks. Typically, these blocks will be defined by either natural, or excavation induced, jointing.

Jan 1, 1999

By R G. Richards

Although most New Zealand coals are low in ash, there are situations where high ash coals could be won. Not all high ash coals can be upgraded by physical means, since the ash is either inherent in the coal or bound in such a way to make its physical removal either impractical or uneconomic. Nevertheless, the authors believe, the situations where high amounts of ash can be economically removed by physical means to make a saleable product are considerable.

Jan 1, 1979

The mining industry, both here and internationally, is continually developing increasingly sophisticated software to compute mineral resource estimates, but these processes cannot compensate for a flawed geological interpretation of the geology of the economic commodity(s) concentrations. Quality assurance and quality control (QA/QC) is becoming increasingly common in association with the sampling and assaying practices within the industry. However, it is rare in the case of a geological interpretation associated with mineral resource estimation. Why? In the context of this paper, QA/QC relates to the use of statistical and graphical tools to show that the geological economic commodity concentrations have been appropriately domained. Domaining is essential to improve the chance of getting a mineral resource estimate right. Commodity value and acceptable concentration variation within a mineral resource can be ingredients that make mineral resource estimation difficult to get right. But it is possible to get it right a very high proportion of the time. It is more likely to occur when inappropriate data consolidation is minimised. In any case, inappropriate data consolidation is significantly reduced when the geological interpretation is strongly consistent with the data and it is demonstrable. To achieve quality global estimates of geological domain concentrations, it is essential that the geology of the prospect is understood sufficiently that the deposit is appropriately domained. Appropriate domaining occurs when sample populations are separated in such a way that only data in harmony with each other within the population contributes to the domainÆs concentration estimate. The paper will use four brief case studies to illustrate how QA/QC can be used to display data and validate the underpinning geological interpretation through its associated domaining to get it right when it comes to a mineral resource estimation.

Jan 1, 2007

By Ibil S

The Gameta Gold Deposit is located on the north-eastern corner of Fergusson Island in the D'Entrecasteaux Islands of Milne Bay Province, PNG, at lat. 9¦ 25' 5, long. 150¦ 47' E or AMG co- ordinate 256740 E/8959000 N (Figure 1). The area is covered by the Fergusson (SC56-05) 1:250,000 scale Topographic Map Sheet and the Koitabu (9079)1:100,000 scale Topographic Map Sheet. The property is held 100% by Union Mining NL (UMG) and lies 105 km NNE of Alotau and 33 km to the ESE of UMGs recently developed Wapolu Gold Mine, a Joint Venture between UMO (51%) and Macmin NL (49%). The inferred resource estimated from surface results and 105 RC drill holes, currently stands at 1.89 million tonnes at 2.6 git gold (1.0 g/t Au cut-off) or 155,000 oz. Evaluation of the property is currently proceeding. To date 111 RC holes have been drilled for a total of 4611 m.

Jan 1, 1997

By J R. Leeming

Mines require ventilation to ensure an adequate atmosphere for the sustenance of life, and to dilute, render harmless and remove contaminants.This paper describes the developments in the United Kingdom (UK) from natural ventilation, through the introduction of fire and simple fans, to modern fully independent and remotely monitored and controlled installations.CITATION:Leeming, J R, 2017. The history of mine ventilation in the United Kingdom, in Proceedings Australian Mine Vent Conference 2017, pp 271–276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

Purification of Nickel and Cobalt from Heap Leaching Effluents Using Ion Exchange Resins A comparative study among several chelating resins for purification of a heap leaching effluent from a nickel laterite ore has been finished. Chelating resins with iminodiacetate (IDA) and bis-picolylamine (Bis-PA) functional groups, from different suppliers, have been evaluated for their selectivity and loading capacities for nickel and cobalt over impurities. The two evaluated IDA resins, Amberlite IRC 748 and Monoplus TP 207, showed very similar results for both loading capacity and selectivity. Better performance was obtained at 7 BV/h at a pH of 4. Evaluation of Bis-PA resin showed that XUS 43578 has better performance than TP 220, with a 30 per cent higher loading capacity and superior selectivity for nickel over impurities.

Sep 13, 2010

This monograph presents a unified theory of adsorption and desorption of aurocyanide on activated carbon. This theory has proved useful for CIP/CIL carbon adsorption and Zadra and AARL elution process and equipment design; in accounting for the effects of various water qualities and process temperatures; and in the development of reagents to improve these processes. The theory presented is based on rigorous fundamentals : Classical Eyring theory links initial first order kinetics with Langmuir isotherm equilibria, and this isotherm is demonstrated for the first time to be a consequence of the activated complex postulate of Eyring theory. Simple extension to Freundlich conditions at high solution tenors is possible, but not presented. Supporting entropy data determined by the author includes practically all the pioneering CIP plants built in South Africa and Australia in the early 1980s.

Jan 1, 1991

By P F. Hodkiewicz, J de Lacey, M Stewart, R Lane

"Implicit modelling is an approach to spatial modelling in which the distribution of a target variable is described by a unique mathematical function that is derived directly from the underlying data and high-level parametric controls specified by the user. This modelling approach may be applied to discrete variables such as lithology (after converting the discrete codes to numeric values) or to continuous variables such as geochemical grades. This paper discusses the estimation of continuous (grade) variables using implicit modelling.One of the underlying engines of implicit modelling for producing this mathematical function description is the radial basis function (RBF). In essence, the RBF is a weighted sum of functions positioned on each data point. A system of linear equations is solved to derive weights and the coefficients of any underlying drift model coefficients. Once derived, the RBF may be solved for any unsampled point or averaged over any volume to provide an estimate of grade. It is possible, for example, to query the RBF on a regular grid to derive an estimate of block grades. Given the ease of creation of an RBF, and its ability to predict grade, the question arises as to how the grades derived from the solution of an RBF compare with grade estimates derived from conventional geostatistical interpolation methods (eg ordinary kriging (OK)).The purpose of this paper is to describe in lay terms: the basic structure of an RBF the role of parametric choice in the solution of RBFs and how this influences the character of the solution the fundamental similarities and differences between RBFs and conventional geostatistical estimators.Using a high-resolution conditional simulation, we show that in many situations RBF and OK estimates are very similar.CITATION:Stewart, M, de Lacey, J, Hodkiewicz, P F and Lane, R, 2014. Grade estimation from radial basis functions – how does it compare with conventional geostatistical estimation?, in Proceedings Ninth International Mining Geology Conference 2014 , pp 129–140 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By S Harrison

Work health and safety duties around Australia include duties to manage psychosocial health and safety (mental health) of workers engaged by businesses or undertakings and of other persons impacted by the operations of the business or undertaking. Persons conducting a businesses or undertakings must develop systems of work and policies and procedures for ensuring, so far as is reasonably practicable, the safety and health of workers and other persons. Officers have a duty to exercise due diligence and to ensure effective systems are developed, implemented and resourced. The developed systems will only be effective with worker’s co-operation and engagement. The duties placed on workers by work health and safety laws are an important part of the safety matrix of obligations. Supervisors and Leaders are workers and they play a critical role in delivering health and safety outcomes. To deliver these health and safety outcomes with respect to psychosocial safety Supervisors and Leaders need to understand their obligations and have a framework to use to assist them in understanding what workers require and what steps need to be taken to meet their duties. They also need to take steps to assist those workers that they supervise to meet their duties.

Apr 16, 2024