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By S Jeffrey, S Mundell, F Arboleda

In the current cycle of low commodity prices and rising costs, mine managers continue to focus on optimising mine performance and productivity. A critical component of strengthening performance and productivity is ensuring material is routed correctly and efficiently through the core mine production activities of drilling, blasting and grade control.By the time a blast is planned, an enormous amount of intellectual property has been invested in the exploration, resource development, feasibility studies and mine planning activities. The value of that knowledge is either realised or diminished during mine production. Efficient execution of the process is critical and is reflected by the quality and timeliness of the information produced.Multiple teams are involved in the mining extraction process. These teams are all under time pressure to keep the mine equipment operating. One of the root causes of this pressure is the dependency between the teams. They do not operate in isolation, but are a link in a chain depending on the outcomes of each activity. It is essential communication is efficient so tasks can be completed according to the production schedule. Unfortunately, communication fails when unintegrated systems are used because of:- different teams seeing different data, hence there is not an overall, up-to-date view of progress and priorities- lack of cross-functional visibility of data leading to failure to identify errors in time to address or correct issues- teams tending to be siloed and focusing on their part of the process rather than the overall objective.With different systems used for the parts of a common goal, supervisors and managers lack visibility of the process. This makes it difficult to identify process improvement opportunities.Streamlined communications help consolidate all data and activities resulting in improved cooperation between mine production teams. This outcome increases the confidence and efficiency of material routing decisions. It also reduces potential impact to mine performance from errors in early stage tasks like drilling and grade control. Having everyone collaborating off the same trusted data, helps teams identify with common goals and find business improvement opportunities as they appear.CITATION:Arboleda, F, Mundell, S and Jeffrey, S, 2016. Driving mine performance through communication, in Proceedings International Mine Management Conference, pp 117-124 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By J Franz, S Bock, N Hentrich

Artificial ground freezing is the unrivalled method for groundwater control during mine shaft sinking. Moreover, ground freezing may also provide temporary ground support. The fast development of fibre-optic temperature monitoring devices, three-dimensional freeze pipe survey methods and numerical modelling software provide grounds for developing new and reliable tools for ground control during freeze shaft sinking. This paper presents examples of predictive numerical models that are based on back-analysis and calibration of temperature data that covers the complete construction cycle from pre-freezing through to artificial thawing. The back-analyses showed that standard numerical models are not capable of predicting the prevailing thermo-mechanical conditions satisfactorily. This paper describes the development and implementation of new tools for improved consideration of concrete hydration and latent heat, along with the introduction of other algorithms that improve and simplify the efforts of managing complex numerical models. A function is presented that allows for an automated correction of the model’s mesh based on results of three-dimensional freeze pipe surveys. This paper demonstrates that the latter consideration is important, because the often employed assumption of idealised freeze circle geometry in numerical models impacts on the accuracy of such model’s predictions. Subsequently, the verification of these extended numerical models is demonstrated. Due to its flexibility, the FLAC3DTM code was employed for the numerical modelling. This software provides the possibility of implementing additional functions written in internal FISH or Python language into the models. It is concluded that state-of-the-art techniques for freeze hole drilling and surveying, on-site monitoring and advanced numerical analysis provide a significant potential for both the design and the operation of largescale ground freezing measures. The application of the extended numerical models for predictive simulations during construction allows for temporary shaft lining optimisation, for assisting in operational decision making and for compensating temporary loss of monitoring data. Suggestions are made for required future work in order to further improve the developed ground control tools. CITATION:Bock, S, Franz, J and Hentrich, N, 2018. New tools for ground control in freeze shaft sinking, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 393–406 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Mahyera A, Sakashita B, Ahmed U, Abou-Sayed AS

Gas in U.S. coals is primarily composed of 90 to 99 percent methane and up to 10 per- cent carbon dioxide. In composition and heat- ing value, this coal-bed gas is similar to natural gas and can be introduced directly into commercial pipelines after standard condition- ing. The high permeability cleat system in the virgin coal can be exploited in order to drain the coal gas well in advance of mining. Two premining drainage methods have been extensive- ly evaluated in the U.S.; they are 1) horizon- tal boreholes collared from within the mine, and 2) vertical drilling from the surface with fracturing. Limited-size fracture treatments are advocated in order to prevent potential roof damage and the need for added support. An engineering approach to predicting gas flow for different drainage techniques near mining locations is presented. Results can be used in design, i.e. pipeline, compressor. Coal gas drainage from a horizontal borehole and a treated (contained fracture) vertical well for a 6 foot seam have been evaluated. Based on these results, it was concluded that selection of gas drainage techniques will depend primar

Jan 1, 1982

By P C. Miclea

Transportation networks extend every day around the world, requiring safe and well-maintained structures for efficiency and for users’ safety. Due to specific features of the infrastructure, such as longer tunnels, increased traffic and marginal safety rules, fire safety in rail and road tunnels becomes more challenging.The situation becomes more critical due to the global economy and increasing worldwide tourism, with multi-national companies often involved in both design and construction of transportation routes or systems in other countries. Tourism brings the risk of visitors becoming victims in a foreign land; thus, international law becomes more and more applicable to transportation projects all over the world, requiring a consistent approach to safety (UN Economic and Social Council, 2001; US DOT Federal Highway Administration (FHWA) 2006; US Transportation Research Board, Committee on the Role of Public Transportation in Emergency Evacuation, 2008; UK Parliamentary Office of Science and Technology, 1997).There are significant differences between rail and road tunnels, both in their functionality and safety requirements. Most tunnels over a certain length are equipped with emergency ventilation systems capable to control the spread of smoke by creating an air stream in the desired direction. Besides ventilation, fire-life safety (FLS) includes smoke and heat detection by linear or spot detectors, closed-circuit television (CCTV) and public address systems with prerecorded announcements, as well as evacuation signage and monitoring capabilities (Vägverket – Swedish National Road Administration, 2004).There isn’t a consistent, worldwide approach to the design of emergency ventilation systems for tunnels, with significant differences from continent to continent (US DOT Federal Highway Administration (FHWA), 2004, US Federal Transit Administration, Transportation Research Board, 2006). In North America US NFPA 130 and 502 standards for rail and road tunnels, respectively, represent the main criteria, however, they are continually revised and new versions issued every three years. For road tunnels the World Road Association PIARC issues guidelines, but they are not truly enforceable. There are no similar international guidelines for rail tunnels, except general recommendations by the International Association of Public Transport (UITP) (IAPT, 2003).In Europe the Directive #54/EC adopted by European Community Parliament in 2004 requires a minimum level of safety for road tunnels users in all existing and proposed tunnels in the Trans-European road network that are greater than 500 m in length. Authorities having jurisdiction in many other individual countries, such as Australia, Austria, Germany, Japan and others, enforce specific safety regulations (Miclea et al, 2007). While it is impossible to summarise all aspects of this topic in a short paper, a review of the design approach, the existing differences in safety requirements, as well as applicable design solutions to meet safety codes for both rail and road tunnels are discussed below.

Mar 8, 2011

This paper will first discuss the fundamental requirements for reliable discharge of backfill by gravity alone at high per cent solids. This discussion will include brief mention of the underlying principles of saturated solids flow contrasted to that of stirred tank or dilute discharge systems. Here the need to possess full knowledge of the flow properties of the stored material will be highlighted. In addition proper account must be made of the silo overflow weir and settling capacity to match plant throughput. Here opportunity will be taken to highlight the complexity of this multi-phase flow situation as well as the general yet paramount requirements for reliable solids flow. It will be shown that by proper attention to the multi-phase considerations gravity discharge of slurries as a consolidated bed with minimal water content is possible. Such high solids discharge results in greatly reduced demand for process water. In addition pumping costs are reduced as is the delay time associated with the mine drainage operation. Confirmation of successful applications will be highlighted by reference to several recent case studies. In the concluding phase mention will be made of the key yet very simple and effective operation techniques which enhance reliable discharge. The simplicity and reliability of properly designed gravity discharge backfill tank systems suggests increased application of this technology by the mining industry.

Jan 1, 1998

By B Yang, S M. Aminossadati

Transporting coal by means of conveyor belts is very common in Australian underground coal mines. Major conveyor belt-related mining incidents are now relatively infrequent as a result of recent improvements in engineering standards and use of fire-resistance materials. However, conveyor belts have the potential for incidents capable of causing either personal or structural damage. In addition, any unexpected break down of rolling components or failure of belts creates a significant interruption to the production that is a major concern for operators whose responsibility is to achieve the optimum mining production.Currently, underground coal conveyor belts are examined for the presence of any overheating, smouldering or unsafe conditions likely to cause a fire. Periodic inspection of operating conveyor belts is carried out with the aim of detecting any local heat sources in an early stage. This includes temperature measurements of the driving head, idlers and rollers using hand-held temperature sensors such as infrared cameras or laser temperature sensors. The disadvantages of current conveyor belt temperature monitoring systems include high labour and equipment costs, safety risk to personnel who are in close proximity to moving conveyors, the ability to take line of site measurements only and potential for missed overheated idlers. Some of the conveyor idlers in underground coal operations cannot be accessed for traditional temperature measurements. This introduces a significant risk to the operation of critical infrastructure.A distributed temperature sensing (DTS) system can be used to develop an advanced conveyor belt temperature monitoring system that provides real-time, accurate and continuous temperature measurements along a conveyor belt particularly at the rolling components. The DTS system comprises of fibre optic detection cable, DTS controller and interfacing module. The advantages of the system include the accuracy, low-cost, easy installation, robustness, safety, immunity to radio frequency and electromagnetic interference, real-time data collection, and secure data transmission. This paper presents a scoping study on the development and utilisation of a fibre optic-based DTS system for underground coal conveyor belts. The mechanism of heat generation, the operation temperature range and the installation issues of fibre optic cable along the conveyor belt particularly in close proximity to each end of the spindle on every idler will be discussed.CITATION:Aminossadati, S M and Yang, B, 2013. A scoping study on fibre optic-based temperature monitoring of underground coal conveyor belts, in Proceedings The Australian Mine Ventilation Conference , pp 35-42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By D Teyhan, J Kirsch

Traditionally, most Australian iron ore mining operations have been surface-based. Processing plants were designed to handle dry ores. In recent years mining operations in the Pilbara have progressively moved below the water table exposing wet, sticky ores which have caused lost efficiency in screening operations as particles tend to agglomerate and adhere, blinding screening media. Miners and vibrating screen manufacturers have experimented with a shift from linear motion to elliptical motion screens. Elliptical motion conveys and lifts particles. Effective on flat deck (horizontal and inclined) or sloping decks it can be configured to provide a controlled transport rate, applying pressure in all directions to maximise screening efficiency. In practice, elliptical motion screens have proven to be effective in dislodging sticky particles from screening media, reducing blinding rates and improving screen efficiency. Moisture and clay content change during the life of a mine. These changes are sometimes the effect of seasonal rainfall, in other cases due to increased groundwater and clay content as mining operations go deeper. To compensate for such changes and optimise screen efficiency, changing the ‘shape’ of elliptical screen motion is required. This has traditionally required shutting down processing plants and making mechanical screen adjustments. Plant downtime is costly and machine adjustment has been a ‘trial and error’ practice. This paper will explore the results of a field trial that is currently underway in Brazil of a next generation elliptical motion screen design that allows operators to make changes to exciter rotational direction, speed and screen stroke angle, through electronic drive phase control. The machine’s electronic drive system synchronisation is enhanced for stability with a unique mechanical timing system. Operating at up to 6 g, screen adjustments can be made on the fly without stopping production. Early trial results are showing up to 50 per cent improvement in screen efficiency compared with traditional elliptical motion machines under certain feed conditions.

Aug 24, 2022

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 J Palise

As cities become more populated and the need for tunnelling increases, we continue to dig deeper urban tunnels in more challenging ground conditions. At the same time our expectations for durability and long-term performance are increasing.It has become increasingly apparent in recent years that repairing water leaks in tunnels can be very costly and unplanned infiltration can cause undesirable outcomes for long-term maintenance costs, structural durability and environmental impacts. For this reason, tunnel constructors are investing more time and effort upfront into drainage and waterproofing systems.Tunnel membrane systems are becoming accepted as a necessary part of tunnel construction, however the knowledge surrounding selection of appropriate systems, design detailing and installation methods has not increased at the same rate. Currently Australia relies heavily on International Standards from Europe and the United States with no immediate program in place to establish our own locally relevant industry standards.This paper gives an overview of where the industry in Australasia is heading in terms of adopting relevant standards. Current basic waterproof detailing options for drained and undrained tunnels with success and failure of various methods are also addressed. Finally we look at the Brisbane Airport Link as a case study for how tunnel waterproofing contract methods, design and installation issues are being addressed in context with recent projects including the Epping to Chatswood Rail Link in Sydney, Auckland Northern Gateway Tunnel, Eastlink Tunnel in Melbourne and Sydney City West Cable Tunnel.This paper’s primary objective is to propose guidelines for how tunnel waterproofing could be implemented on large infrastructure projects in the future and to map a path for preparing and introducing a ready to use document for selecting appropriate tunnel membrane and drainage systems whilst implementing detailing methods which are appropriate for local conditions.

Mar 8, 2011

By K Williams, W Chen, J Miller

The flow function of an iron ore material governs its flowability characteristics in material handling chains within the resource industry. A uniaxial compression test is able to obtain a flow function more rapidly comparing to the Jenike direct shear test; nevertheless, the results often exhibit lower rankings using the former method. This study aims to investigate the fundamental stress states within the test specimen that lead to this phenomenon, and to introduce a new uniform density specimen preparation method for a uniaxial compression test, in order to achieve comparative flow functions as for a Jenike direct shear test. The minimisation of the wall friction effect and achievement of the critical state when preparing a uniaxial specimen are explicitly discussed. Experimental investigations on flow functions of a suite of Australian iron ore samples were conducted using both the uniform density uniaxial compression test and the Jenike direct shear test. Results from both methods were found to be comparable, providing the specimen exhibits cohesive flow behaviours. The outcome of this research enabled development of a rapid and reliable flow function testing method for cohesive iron ore materials.CITATION:Chen, W, Williams, K, Roberts, A and Miller, J, 2017. Rapid and reliable flow property testing – a modified uniaxial approach, in Proceedings Iron Ore 2017, pp 149–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By C Simpson

In 2011 the forecasted world demand for iron ore continues to grow, and during this time Australia is looked upon as a reliable supplier of high quality ore. The expansion of the current Australian mines is unlikely to meet the forecast demand. New mines are therefore being actively explored for and when discovered, are quickly being developed into mines in order to meet the world’s hunger for steel.The Solomon Project area is a large new iron ore discovery, located in the central Hamersley Ranges of the Pilbara province in Western Australia. The first Fortescue exploration drill holes commenced on the project in 2007 and to date three billion tonnes (Bt) of iron ore have been defi ned within the project area. Fortescue is fast-tracking the development of the ‘Solomon Stage 1’ project, with rail and mine construction commencing during 2011, and ore to be railed to Fortescue’s existing shipping operations at Port Hedland commencing in 2012. At a designed production rate of 60 Mt/a, the Solomon operation will be one of the biggest production centres of iron ore in the Pilbara.Deposit types include the three dominant mineralisation styles of the Pilbara province, being bedded iron deposits (BID), Channel iron deposits (CID) and detrital iron deposits (DID). All these mineralisation styles are present in large concentrations within the Solomon project area, and when mined will produce two product streams. These are a single product of CID, and a combined product from a blend of BID and DID material.This paper defines the geological characteristics of the Solomon iron deposits as recognised through the exploration and development of this vast resource over the three years since exploration commenced on the project.

Jul 11, 2011

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 D Teyhan, J Kirsch

Traditionally, most Australian iron ore mining operations have been surface-based. Processing plants were designed to handle dry ores. In recent years mining operations in the Pilbara have progressively moved below the water table exposing wet, sticky ores which have caused lost efficiency in screening operations as particles tend to agglomerate and adhere, blinding screening media. Miners and vibrating screen manufacturers have experimented with a shift from linear motion to elliptical motion screens. Elliptical motion conveys and lifts particles. Effective on flat deck (horizontal and inclined) or sloping decks it can be configured to provide a controlled transport rate, applying pressure in all directions to maximise screening efficiency. In practice, elliptical motion screens have proven to be effective in dislodging sticky particles from screening media, reducing blinding rates and improving screen efficiency. Moisture and clay content change during the life of a mine. These changes are sometimes the effect of seasonal rainfall, in other cases due to increased groundwater and clay content as mining operations go deeper. To compensate for such changes and optimise screen efficiency, changing the ‘shape’ of elliptical screen motion is required. This has traditionally required shutting down processing plants and making mechanical screen adjustments. Plant downtime is costly and machine adjustment has been a ‘trial and error’ practice. This paper will explore the results of a field trial that is currently underway in Brazil of a next generation elliptical motion screen design that allows operators to make changes to exciter rotational direction, speed and screen stroke angle, through electronic drive phase control. The machine’s electronic drive system synchronisation is enhanced for stability with a unique mechanical timing system. Operating at up to 6 g, screen adjustments can be made on the fly without stopping production. Early trial results are showing up to 50 per cent improvement in screen efficiency compared with traditional elliptical motion machines under certain feed conditions.

Nov 8, 2021

By G McCullough, J Els, J Bassan

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

Sep 18, 2023

By Casley G. E, Pritchard J

A single slurry fed fluosolids roaster was chosen to replace six multiple hearth roasters in the Copper Smelter at Mount Isa as part of the overall program to increase production from 100 000 to 155 000 tonnes blister copper per annum. The paper describes factors influencing the choice of the unit, problems encountered during the commissioning and details of the present roaster operation.

Jan 1, 1974

The state of sampling practice in South African minerals industry must be appreciated in the context of the changes that the country has recently lived through. These include the entrepreneurship and investment in local mineral developments, the 'unbundling of mineral assets', the rising foreign control of South Africa's mineral assets, developments in the regulatory environment, and the training that has come to the industry through international experts. In terms of their financial contribution the five most important commodities in the South African mining industry include gold, platinum, non-ferrous metals, ferrous metals, and coal. International Organization for Standardization (ISO) standards form the basis for international trade in two of these commodities and have had a steadying influence on sampling practice over the years. The contribution of the minerals industry to the economic well-being of South Africa and the strong financial links between good sampling practice and minerals marketing, has acted as a driver for improved sampling practice. The state of sampling practice at mining operations of the five main commodities was found to be quite widely divergent with 'pockets of sampling excellence' in each of the commodities. The stages of mineral development at mines for each of the commodities have been described in terms of the sampling sites, sampling mechanisms, and associated problems at different stages of mineral production from exploration, through face sampling, blasthole sampling, and in-mine grade control, ore processing and handling, metallurgical subsampling, process subsampling, and subsampling in the laboratory. In each case the principal errors were identified and their potential impact on value erosion was estimated. In the final analysis it is evident that the greatest problems arise in the early stage of mineral development, and that ferrous metals and coal are particularly susceptible to loss of value through poor sampling practice. Several examples of value lost through poor sampling at the marketing stage that arise from breaching contract specifications, either in terms of grade or sizing, are described. The conclusion is that larger companies with larger ore deposits and greater human, financial, and capital resources are probably more compliant with 'best sampling practice' than smaller companies. Finally the message that equipment suppliers are sending is that business is booming and the awakened awareness of the issues around sampling practice are translating into rands and cents spent on improved sampling equipment.

Mar 1, 2010

The major technological advances of the last 30 years have profoundly reshaped mining practices. Machines keep getting bigger while productivity continues to increase and manning levels drop. These trends will continue and the introduction of breakthrough technologies will continue to accelerate, driven by a continued focus on lowering the cost of production, improving the productivity of workers and machines, and ensuring safer working environments. At the same time, global consolidation of mining companies has impacted on technology development in a range of ways. There are many potential technologies being proposed, some already operating in Australian mines. The automation of underground load-haul-dump (LHD) trucks for example, continues the process of removing workers from the most dangerous operating environments. Global positioning systems fitted to draglines, fibre optic communication channels, and 400 tonne trucks are only some examples of what lies ahead. However, where we need to return focus is to the technology of management û which is also one of the two key interrelated themes of this keynote address. Have we, as an industry, adequately been able to keep up with technological advances? Are our management systems as competent as the machinery we employ? The other key theme is the processes of globalisation and consolidation. What are the impacts on our industry? What are the implications of these processes, particularly for the ways in which we manage our people? My paper is divided into several components:some comments on the coal industry and the dramatic restructuring we have seen in recent years; in the context of this restructuring, an overview of my company and its evolution; my views on the role of contractors; some comments on the consolidation also occurring in the mining machinery and equipment, technology and services sectors; some observations on two major areas of technology û drill and blast; and trucks, shovels and excavators; the implications of consolidation and new technology for our employees and management; and finally some comments on research programs.

Jan 1, 2001

By S J. Neethling and, S J. R Simons

In this paper the effect of humic substances (natural surfactants), electrolytes and solid particles on bubble coalescence, and as a consequence on froth stability, have been investigated. In this study two bubbles of equal size were formed and forced to collide using a novel experimental apparatus. The interactions were recorded by a high-speed camera, the images of which helped to determine the coalescence frequency and the coalescence time, as well as the mechanisms of the interactions. Two types of humic substances were used, along with three different electrolytes. Humic substances appeared to have a considerable effect on bubble coalescence, while the effect of electrolytes was minimal. Moderate and high hydrophobic glass spheres were used between two bubbles. Very hydrophobic spheres promoted fast bubble coalescence, while moderate hydrophobic spheres had no effect. Data of coalescence frequency and time is presented, as well as images of the coalescence events. The coalescence frequency was used to validate a parameter, Pf, known as the film failure frequency, used in a simulation model to predict foam height in a gas-sparged vessel. Predictions determined using Pf were then validated by experimentation.

Jan 1, 2005

RME has a vision for a new grinding plant operational paradigm made possible by RMEÆs fast, safe Mill Relining System. Some new liner designs can degrade SAG mill performance because of mill volume loss, ball strike (rotational speed limitations) and other issues often brought about by modifying liner design for maximum life and without a backward glance at metallurgical consequences. Freshly relined mills can initially produce as little as 80 per cent of their maximum throughput, that maximum occurring toward the end of the linersÆ wear life. RMEÆs proposition is to see new liners designed for maximum commercial performance. This may mean more frequent mill relines but with liners designed to yield optimum grinding, metallurgical and profitability performance, not maximum life. In other words, mill liner profiles and mill relining speed become key operational controls and not simply æmust doÆ maintenance functions. Taken to the extreme, liner profiles may prove capable of ætuningÆ a grinding plant for maximum profitability in any metal price environment. Following the introduction, the first section of this paper provides an update describing recent and significant developments within RMEÆs range of Mill Relining Systems, the enabling technologies which permit more frequent liner exchange without incurring additional downtime imposts. The second section outlines RMEÆs vision of a æliner profile versus profitabilityÆ commercial model, developed either intuitively or by using a combination of new measurement and modelling technologies. These new measurement and modelling tools provide the opportunity to predict the optimum commercial outcome, off-line in the virtual world, before committing to an expensive liner experiment.

Jan 1, 2007

By J A Evans

A well-maintained and low cost mining operation today requires the use of condition monitoring techniques. At ERA - Ranger Mine oil analysis, vibration monitoring, infra-red themtography, and performance analysis have been successfully applied over the last four years to lower operating and maintenance costs. All condition monitoring is scheduled through a comprehensive in-house developed maintenance management system known as the Engineering Information System (EIS). (EIS) is used extensively at Ranger to ensure consistent frequency and recording .of all condition monitoring data. This paper provides an insight into the benefits of condition monitoring and explores the future direction for condition monitoring techniques at Ranger.

Jan 1, 1994