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As mines become deeper, the problems of heat in the workplacebecome more acute. An important response from the industry hasbeen the widespread adoption of microclimate cooling such asair-conditioned cabins. However, not all work in mines can becompleted from inside an air-conditioned cabin, and in any event,it is still important to keep the ambient air in the mine outside ofany microclimate to a safe temperature. An important method forbringing workplace temperatures under control is the appropriateuse of refrigeration. The application of refrigeration inmechanised mines has been recently described (Brake, 2001;Brake and Fulker, 2000). This paper provides an overview ofsome of the important engineering considerations in thespecification and selection of mine refrigeration plants. Thepurpose is to provide a basic understanding of refrigerationprinciples, practices, terminology, hazards and opportunities formining engineers or other personnel who may need to beinvolved in the introduction of refrigeration onto a mine site.

Jan 1, 2001

By A Havenga, F, J Hough, R Grobbelaar

After the closure of mines they naturally start to fill up with water. As a result, hydraulic gradients develop between adjacent mines and different hydraulic water pressures are exerted onto peripheral areas or compartments within mines. This results in water flow between mines, or onto the surface. This flow is referred to as intermine flow. The geometry of the collieries in the central Witbank Coalfield make intermine flow possible in several areas. Since the Department of Water Affairs and Forestry declared intermine flow as one of its greatest concerns for granting closure to South African mines, much research into this phenomenon has been undertaken. The importance of the quantification lies in the DepartmentÆs goal of sustainable water management, and the possible long-term financial implications these flows could have for individual mines. The challenges of determining intermine flow are numerous, and attention is focused on the identification of areas where these flows can take place. Detailed mining plans on a regional scale are required, and detailed coal-seam floor data are combined to provide targets for possible interaction between these mines. The quantification of these flows is problematic due to the uncertainties regarding geometrical configurations and the variation in site-specific hydraulic characteristics of the coal and overlying lithilogical layers. To this end, use has been made of several analytic solutions and numerical flow modelling. Stage curves (volume versus elevation curves) for the opencast and underground workings have been calculated and first-order estimates for intermine flow or decant from these areas have been determined. The numerical modelling methodology entailed a down-scaling approach, starting with a broad regional model covering the entire area, followed by modelling the interactions between interconnected mines and finally looking in detail at the major areas of interaction. By considering different scenarios within the context of these flows, possible management options for intermine flow can be evaluated in terms of volumes and qualities that might emanate in the post-closure phases. Challenges for the future include obtaining site-specific information on the groundwater hydraulics and acceptable ranges for model parameters, and verifying model results over time.

Jan 1, 2003

The Mount Isa mine in North West Queens- land produces a total of nearly 10 million t/yr from separate copper and silver lead zinc orebodies. Sampling information is mainly obtained from diamond drilling on 30 to 40 metre centers in both types of orebodies. For the copper orebodies the majority of the core is analysed for copper content using a non-destructive bulk analyser developed by the Australian Atomic Energy Commission. The diamond drill core in the silver lead zinc orebodies is usually sam- pled as sawn half core and assayed in the com- pany laboratory using a variety of methods dependent upon the level of metal content and/or the elements required. Underground development is sampled where additional information is required to improve the ore reserve estimate. The copper areas are sampled using a standard 2.0 m by 2.0 m chip sample of the wall. The chips are taken on a 250 mm spacing. Lead areas are sampled using a 100 mm wide by 4 mm deep channel over intervals determined by the area geologists. The massive, irregularly shaped copper ore bodies are mined as large sublevel open stopes and pillars. Ore reserve estimation on both a production unit and global scale is routinely carried out using a geostatistical system developed in-house and running on a Sperry 1100 mainframe computer. Copper grade, tonnes and the Kriging var- iance are estimated at points on a user defined grid. The Kriging program uses 10 m assay composites from diamond drill core and underground chip samples. One average (rela- tive) variogram is used throughout the main copper orebodies. The validity of using an average variogram was verified by the original geostatistical study undertaken in the late 1970's.

Jan 1, 1987

By T Raynlyn, A Edenton, M Adam, R J. Holmes, J R. Manuel, N Ware, R Smyth

Due to ongoing demand and increasing depletion of high-grade iron ore resources from large deposits, Australian iron ore producers are developing smaller size deposits to maintain current export levels. The iron grade, mineralogy, chemical and physical characteristics of iron ore fines being mined from different deposits vary considerably. It is therefore imperative to develop long-term strategies to maintain the quality and consistency of iron ore fines while moving to a larger diversity of smaller deposits. Blending is a common practice in sinter plants as it is almost impossible to produce a high performance sinter mixture displaying the required characteristics from one single ore. Blending is also one of the most effective options being used by iron ore producers to ensure the long-term stability of their products while increasing production. When designing a blend, the blend components are selected to support each other to achieve the required overall balanced metallurgical performance of the final product at a relatively low cost. To do so, a fundamental understanding of the key characteristics of iron ore fines and their potential impacts on the iron ore sintering process and sinter quality are required. In this paper, the sintering process and sinter structure have been analysed and the key factors affecting the sintering performance of iron ore fines, including productivity and quality, identified. Under fixed sintering conditions, the granulation efficiency, nuclei stability and the volume and properties of the primary sinter melt are believed to have important impacts on both sintering productivity and sinter quality. Discussion is then focused on the effects of ore chemical, physical and mineralogical characteristics on the key factors identified and in turn the consequences for sintering productivity and sinter quality.

Jan 1, 2009

By A G. Pavlides, B L. Weekes

The Sepon Copper Project is located in the Savannakhet Province of Laos PDR and is operated by Lane Xang Minerals Ltd (LXML). An Ausenco - Bateman Engineering joint venture, the Khanong Development Group (KDG) managed engineering, procurement and construction of the project. The plant was fully commissioned in March 2005, two weeks ahead of schedule. The plant is designed to produce 60 000 tpa of cathode copper. The process flow sheet includes a pressure oxidation (POX) circuit that leaches pyrite flotation concentrate to generate ferric ions and sulfuric acid for use in atmospheric leaching of a predominantly chalcocite ore. The process is unique in that the chemistry in the autoclave is forced to produce a basic ferric sulfate precipitate for downstream recovery of ferric iron. This paper describes the design, construction and commissioning of the pressure oxidation circuit. The challenges imposed on construction and commissioning due to the remote location of the site, landlocked status and underdeveloped infrastructure in Laos are highlighted.

Jan 1, 2005

A new lead refinery with a. capacity of 230,000 tons per year com-menced operation at*Port'Plsie in October, 1959. This plant' superseded the refinery which had operated from 1933 with the advent of thecontinuous lead refining process. The incorporation of new equipment following local metallurgical developments, together with the overseas demand for lead of extremely low antimony content, created difficulties in operating the original plant. The new refinery project was under-taken to cover this disability and to gain the full advantage of the new processes.Desilverising and softening are carried out in units identical in size to those used previously. Metallic'zinc is now recovered from the entire output of desilverised bullion by vacuum distillation. Final refining is then carried out by batch'treatinent with caustic soda yield-ing lead of purity previously unattainable at Port Pirie.These two processes have replaced continuous dezincing by oxidation, a high temperature process which caused large quantities of lead and antimony to be recirculated. As the final stage is a .batch process the product composition can be.checked before casting. Individual batches can be adjusted to produce special alloys to,consumer's specification.Improved casting equipment has allowed the quantity production of pigs of good physical characteristics either as 56 lb bars or 2000 lb pigs. This, together with the high purity of the lead, has assured the B.H.A.S. position in world markets.Automatic control systems have been extensively employed particularly on the vacuum dezincing unit.The anticipated financial benefits have been achieved mainly by a reduction in the tonnage of recirculated materials, a smaller labour force, and reduced maintenance requirements.

Jan 1, 1963

The 1990s present many challenges, not the least of which is in the area of health and safety. Integrating of safety and health into the management process to suit the overall needs of a company will require commitment. Organisations which consistently perform to high success levels do so because they plan it that way. By using tools of total quality management, the potential to continually improve all safety processes exists. The successful integration of total quality measurement principles used in the improvement of safety processes, and the measurement of performance-based activities allow for prevention of accident causing scenarios and performance improvement.

Jan 1, 1993

By M I. Pownceby, J Manuel, S Suthers, A Poliakov, E Donskoi, N Ware

"The mining industry is constantly seeking methods for optimising the exploitation of mineral resources, such as iron ore, in a sustainable and eco-efficient manner for economic and social benefit. When faced with resources that have mineralogical or textural complexity, poorer grades or geological variability, it is particularly important to apply a comprehensive geometallurgical approach to the development of the mining operation, from resource definition through to processed product. Integral to this approach is the quantitative characterisation of representative samples across the whole orebody.A key factor that associates the geological characteristics of iron ores to their processing response is ore texture. While the classification of samples on the basis of chemical or physical properties alone is often not sufficient to predict their processing behaviour, classification and quantification of texture types can be effectively correlated to metallurgical performance in processes such as blending, beneficiation, pellet making, sintering and ironmaking. This paper describes some of the research conducted by CSIRO pertaining to the design and rationale of a texture-based classification system for Australian iron ores; some of the tools developed and used to apply such classification; and the application of the generated data to quantifying, modelling and predicting sintering behaviour and performance in the blast furnace.CITATION:Suthers, S, Pownceby, M I, Manuel, J, Ware, N, Donskoi, E and Poliakov, A, 2016. Geometallurgical Characterisation of Australian Iron Ores – from Ore to Processed Product, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 351–360 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By R Trueman

An improved ability to predict dilution for narrow vein deposits enables more accurate economic comparisons between mechanised longhole stoping and other narrow vein mining methods, as well as reducing uncertainty surrounding dilution estimates for deposits at the prefeasibility/ feasibility stage. This paper proposes narrow vein dilution prediction and minimisation strategies for both greenfield sites and operating mines, respectively. The narrow vein dilution method (NVD method) is a tool for more accurately predicting longhole narrow vein dilution. The method is based on a new concept called benchmark stoping width. Benchmark stoping width is based on probabilistic analysis of overbreak distributions from a typical longhole narrow vein mine. The premise for the NVD method is that dilution associated with longhole stoping can be predicted using the benchmark stoping width. In addition to dilution prediction, the NVD method also includes strategies for narrow vein dilution minimisation generally, including; filling, cablebolting, stress relaxation, extraction sequencing and blast overbreak.

Jan 1, 2008

This paper describes the planning mechanism and implementation of a progressive rehabilitation programme at Hunter Valley Mine in the Upper Hunter Valley of New South Wales. Hunter Valley Mine is a large open cut coal mine which produces approximately 7.0 million tonnes of coal (run of mine) annually for export. This production level involves the movement of some 60 million tonnes of waste and coal each year.The rehabilitation programme at Hunter Valley Mine has been developed to provide a combination of pasture, based on improved pasture species and timber belts to enhance the visual characteristics of the rehabilitated landform, whilst creating amenity in the form of shade for livestock.The operational philosophy for the rehabilitation programme is that of progressive rehabilitation. The best time to undertake rehabilitation is now.' As a result, planning for the rehabilitation programme is continuous, so that all site works are completed in time for vegetation establishment during the critical periods each year.

Jan 1, 1992

Synthetic and commercial activated carbons are characterised for several chemical and physical properties. A range of techniques is used to establish correlations between physicochemical parameters and gold- adsorption activities. The most important parameter in the carbon activation process for a product with a high gold-adsorption activity is the activation temperature. High activation temperatures yield products with large micropore volumes which provides sites that are ideal in size for adsorption. The surface area of an activated carbon is not necessarily a good measure of its adsorption activity. Surface oxygen-containing functional groups are identified by Fourier transform infrared spectrophotometry to be comprised mainly of ethers and hydroxyls. These functional groups line the edges of the micropores imparting a polar character to the pore and aid in the solvation of the adsorbate. Oxidants such as nitric acid result in a proliferation of surface carboxyl groups. resulting in a negatively- charged surface that is not conducive to the adsorption of gold.

Jan 1, 1993

By R E. Gerald II, B Zhang, T Sander, J D. Smith, J Huang, R J. O’Malley, H Tekle

In the steelmaking process, mold fluxes are essential for ensuring thermal insulation, refining, and the efficiency of continuous casting. Real-time understanding of the in-service composition of slags and fluxes are crucial for optimising the steel production process and improving the quality of the final product. An in situ fibre-optic Raman probe that enables the study of the structure, composition, and viscosity of molten slags and fluxes at steelmaking temperatures has been developed and demonstrated both in the lab and in foundry scale experiments. The focus of this study is on the structural, compositional, and property analysis of molten fluxes in a laboratory setting, with the aim of applying this technology for in situ monitoring during industrial production. Raman spectra were successfully collected at various temperatures from 1000°C to 1400°C in real-time and analysed using a deconvolution algorithm to isolate and quantify peaks in the spectra associated with the specific structures of molecular components in molten and solidifying flux. The research successfully combines in situ Raman spectroscopy with high-temperature viscosity data, specifically targeting CaO-CaF-SiO2-Al2O3 based mould flux systems. Specified ratios of the deconvoluted Raman peaks, such as Al-O-Al/Si-O-Si ratio, shows good correlation with the flux chemistry, while the Q3/Q0 peak ratio shows good correlation with viscosity. A ruggedised Raman probe system was also developed and demonstrated in an 80 kg induction furnace. Ultimately, the goal of this work is to demonstrate in situ slag and mould flux analysis in industrial processes, such as in the continuous caster or electric arc furnace (EAF).

Aug 21, 2024

By C Deacon

It is common practice to include microspheres or similar density reducing agents in inherently insensitive water-based commercial explosives to achieve detonative sensitivity in the absence of chemical sensitisation. It has recently become possible to similarly include microspheres in LDAN (low density ammonium nitrate). Further to previous studies and publications to determine the benefits resulting from the use of microsphere enhanced LDAN technology in blasting, additional advantages are described in this document. These include range tests at independent testing facilities (Universal Tech Corporation û USA) which reflect results observed in the field, and support theoretical assumptions made when the products were introduced. Additionally, on-site studies in opencast pits using Heavy-ANFO blends incorporating modified LDAN, show that monetary savings can be realised through significant advantages gained in plant throughput and explosives use.

Jan 1, 1999

By M D. Boscardin, P A. Roy

The North Shore Connector Project for the Port Authority of Allegheny County involves TBM tunnelling twin light rail tunnels through cohesive soils and rock under the Allegheny River and a narrow city street. Along the tunnel alignment are a listed historic building on shallow foundations as well as modern buildings on deep foundations; one major office block was actually constructed directly over the alignment during the latter phases of design process. This paper provides an overview of the general site conditions, tunnel design and the technical basis for excavation support and tunnelling decisions. Deformation limits, ground improvement, monitoring and mitigation plans are also discussed. Project construction has now commenced and a brief summary of progress to date is included in this paper; this will be updated for the presentation to be made in Melbourne.

Jan 1, 2008

By M J. Kelleher

CREAM is an acronym for coal recovery, evaluation, analysis and management and is a business improvement project at BMAÆs Goonyella Riverside mine that is focussed on maximising coal recovered. In August 2003, Goonyella Riverside was set a challenge to quantify coal loss and dilution and their relationship to cost, revenue and ultimately profit. While the mine was confident in its site forecasts of recovery (and loss), it was clear that the traditional measurement and analysis systems were inadequate to firstly, identify key loss areas and mechanisms and secondly, successfully quantify the benefit of various coal recovery initiatives. The path that BMA Goonyella Riverside has travelled to maximise coal recovered can be divided into four key steps: Mapping the process û This step involved the development of a coal flow process map for Goonyella Riverside that stepped through each component of the process from the coal reserve to the customer and identified key measurement points for the purposes of reconciliation. Understanding coal loss and identifying opportunities û This step involved conducting two detailed Reserve to Customer projects at the mine site to track a block of coal from the reserve to the customer and to gain a greater understanding of the relationship of dilution, coal loss mechanisms, revenue and costs associated with recovering additional coal. Coal data systems development û Two important coal data systems have been developed and implemented at Goonyella Riverside in the past twelve months, namely SnowdenÆs Coal Reconcilor and SeamFix. These systems enable coal losses and dilution to be quantified and reconciled back to the initial coal reserve. Implementation of loss reduction initiatives û This step involved the formation of a business improvement project referred to as æCREAMÆ in August 2004, for the purposes of improving pit coal recovery and maximising business value. To date a series of coal recovery trials have been run in a number of pits at Goonyella Riverside that have yielded significant improvements in business value. The key to the success of this project has been the discipline to follow a defined process map, management commitment through resourcing and shared key performance indicators, a successful acceptance strategy resulting in holistic ownership and the implementation of sustainable reconciliation systems. Coal loss and dilution are now quantifiable and their relationship to cost, revenue and ultimately profit is well understood. This paper discusses the process that Goonyella Riverside has adopted to maximise coal recovered.

Jan 1, 2005

Although technology and circumstances are in a constant state of change, the principles of managing the human element remain constant. The isolated mining community continues to form the backbone of the minerals industry but the nature of the isolation, along with the economic and political environment of the industry, is changing. These changes require new inputs by management to the workforce. Management must determine an effective working relationship with unions on its mine site and concurrently contribute to the build- up of the expertise of the individual worker through training and communication. It must also retain a proper balance, by way of human contribution, in cost and information reporting and in other areas amenable to computerisation. These comprise the aids to management necessary to achieve the desired operating efficiency and profitability.

Jan 1, 1980

By M McLean

This paper deals with change strategies on brownfield and greenfield sites in extractive industries. It draws upon contemporary experiences across Australian, Indonesia and Papua New Guinea (PNG). Change strategies can be used when owners of an extractive industry operation want to optimise their resource. This paper draws upon many tried and proven theories and practices, including the findings of the Tavistock Institute (Trist, Emmery, Bamford, Jaques), as well as the concepts of Adult Learning espoused by Malcolm Knowles and is supported by learnings of Australian based management consultants. This paper reviews a range of approaches that have succeeded in the integration of systems, machines and people, with the key corporate objectives of: increasing productivity; decreasing cost; improving on-time delivery performance and achieving long-term survival. Such integration needs to be measured to show the outcomes from the change strategies and the authors have worked within many measurement regimes and metrics but for the most part, found that JaquesÆ set of metrics being æquality, quantity, resources and timeÆ has gained currency across many Australian operations. This paper contends that investing money in machines alone without a commensurate investment into the people side is counter-productive. Further, if there is not an understanding of processes, ie stable and capable, core and support processes, then all that new technologies will do, is to make what is done badly, only quicker. Recent interventions for the most part, have been cognisant of this balanced approach towards change management. The change strategies described are across extractive industry implementations, using a number of tools and techniques drawn from Continuous Improvement and Six SigmaÖ (registered trade and service mark of Motorola Corporation, USA).

Jan 1, 2006

By K Nguyen

The advances in computerised processors and digital microscopic imaging have enabled more studies that attempt to quantify textural information from rock images. However, a texture classification system designed for geometallurgy has always been challenging, as it combines general image analysis techniques and specific texture classifications in terms of the size, shape and orientation of mineral particles. In this paper, a novel texture analysis technique using grey level radial shell association (GLRSA) and spectral angle mapper (SAM) to discriminate between different geological images is outlined. The technique can be applied in routine analysis and characterisation of mineralogical and textural attributes which may correlate with variability in mineral processing behaviours. Using this texture analysis technique, a set of small texture reference images, a texturelet reference library, has been identified from a suite of drill core images. Rock types are classified according to the proportion of each texturelet type recognised. The library is site specific.CITATION:Nguyen, K, 2013. A new texture analysis technique for geometallurgy, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 187-190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Revy T

A testwork program aimed to improve the assaying of underground face samples established that for an Accelerated Cyanidation Extraction using the LeachWELLTM 60X catalyst, followed by an Aqua Regia finish (to quantify non-cyanide-extractable gold): ò Assay results (including the aqua regia finish) from a full set of samples from one underground face can be returned within four hours. ò The reagent dose to make the method simple and 'bullet-proof' is 8 gm LeachWELLTM 60X and 20 gm NaCN per 200 gm sample (30 per cent solids). Pulverising is to 90 per cent passing 75 micron (compared to the standard of 90 per cent passing 150 micron), and cyanidation is completed within one hour - however both might be further optimised. ò The LeachWELLTM/Aqua Regia results demonstrate that Fire Assays suffer from a significant nugget effect which makes the Fire Assay data relatively unreliable. ò Original costs, specific to Bannockburn (viz including an Aqua Regia finish), handling approximately 20 000 to 25 000 per annum is estimated to be $5.40, ie about one-third less than fire assaying. Optimising is further reducing these costs. It is estimated that the LeachWELLT"'/Aqua Regia assay procedure has reduced the probable error limits of any given assay of this ore from the range 0.74x to 1.36x for Fire Assay, to an appreciably smaller range of 0.90x to 1.11x. Thus for a cut-off grade of 1.60 g Au/t, samples with Fire Assays ranging up to 2.18 g Au/t have 25 per cent chance of being below cut-off, while samples with Fire Assays as low as 1.18 g Au/t have an equal chance of actually exceeding cut-off grade. This 1 g Au/t range in uncertainty is generally unacceptable for many practicalgrade/tonnage relationships. By contrast, using LeachWELLTM + Aqua Regia assays, the estimated corresponding limits are 1.44 g Au/t and 1.78 g Auk respectively - a far more tolerable 0.34 g Au/t range of uncertainty. Subsequent data has demonstrated that sufficient accuracy for grade control is achieved by Accelerated Cyanidation alone, further halving the cost of assays.

Jan 1, 1994

By M Thomas, M Caccetta, C Laukamp, A Hacket, M Jones, A Rodger, M Verrall, R Hewson

A mineral systems approach was used to interpret precompetitive airborne mineral mapping geoscience data for iron oxide copper gold (IOCG) exploration in the Starra area, Eastern Succession, Mount Isa Inlier. Selected minerals were chosen to map possible source rocks/fluids as well as intersecting structural/fluid pathways that could have transported mineralising fluids into domains of contrasting rocks/fluids where there was potential for physicochemical gradients to precipitate metals. Ferric and ferrous iron contents and white mica abundance were useful mineral criteria to identify theMount Dore Granite of theWilliams-Naraku Batholith as a potential source of æoxidisedÆ fluids rich in Fe, K and potentially Cu-Au. The Mount Dore Shear Zone (MDSZ) intersects the western margin of this granite with the highest contents and changes in composition of the white mica are peripheral to this contact within the granite. This together, with the fact that the entire N-S length of the MDSZ in the study area (~16 km) is abundant in white mica are evidence of K-rich fluids had preferentially moved along this pathway. To the south, the MDSZ intersects a domain comprising massive ironstone bodies as well as numerous graphitic horizons. This interpreted æreducedÆ domain is well mapped using the æopaqueÆ mineral products, as well as by white mica, which is pervasively developed and extends 2 km either side of the MDSZ fault into the meta-sedimentary sequences. The chemistry of this white mica also changes progressively away from the MDSZ, becoming more Si-rich (longer wavelength) towards the contact with massive ironstone bodies in the west and the graphitic units in the east, both of which represent sites of known Cu-Au mineralisation. Beyond these contact zones of interpreted æoxidised fluidsÆ with reduced rocks/fluids, there is either a rapid change to Si-poor white mica and/or no white mica developed, ie major æchemicalÆ gradient change. These mineral mapping results provide evidence for a direct link between possible source rocks and sites of IOCG metal deposition as well as extending the associated alteration zonation which had previously been mapped/published at the metre-scale to the kilometre-scale. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008