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Many aspects of best practice resource evaluation do not create value, but poor practice can certainly destroy value. Generally companies prefer to present how their good practice adds value and for this reason few publications exist on examples of how poor practice can destroy value. However in big and small companies there are many previous and current examples of poor practice destroying value. The incremental expenditure required to move from poor practice towards best practice can be looked upon as insurance against destroying shareholder value. Examples of how poor practice in geology has destroyed value are presented as well as the improvement model used by BHP Billiton to add value and insure against destroying value.

Jan 1, 2002

By F N. Baez

This paper supplements a keynote address prepared for the MassMin 2016 conference on mass underground mining methods, including block, panel, inclined and sublevel caving. It advocates for a new cave mining paradigm that takes advantage of a number of new and disruptive technologies or innovations that have evolved over the last 15 years, some of which were initiated by major mining companies such as Codelco. The paper will address the challenges that the industry will be facing in the future as well as possible solutions. As background, the paper summarises the challenges that the industry has faced in the past and how such challenges were addressed. The author acknowledges that given his more than 30 years of experience with Codelco Chile (operations and corporate), aspects of his intelligent mining concept have no doubt been influenced and have matured during his invaluable time with Codelco also as the Head of Technology and Innovation. In the paper, he uses some of the innovations developed within Codelco and by the Chilean Government to illustrate the concept of ‘intelligent mining’.CITATION:Baez, F N, 2016. ‘Intelligent mining’ – the way of the future, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A Hocking, S Henderson

Commonwealth of Australia (2016) defines rehabilitation as comprising “the design and construction of landforms as well as the establishment of sustainable ecosystems or alternative vegetation, depending upon the desired post-operational land use”. For open cut coal mines in Queensland and New South Wales, the question of how to apply this intent to pits at mine closure is repeated for hundreds of individual pits. In EISs, closure plans and public discussion, assorted treatments are proposed to rehabilitate pits. While some aspects of final voids have been intensively studied, there is little guidance on how to choose a final void treatment option that delivers the optimal outcome against rehabilitation goals. For example, in the Bowen Basin and Hunter Valley commonly proposed rehabilitation actions include reducing the angles of pit walls; however, with few voids successfully rehabilitated to date there is limited understanding of what different wall slopes will achieve.CITATION:Henderson, S and Hocking, A, 2018. A decision framework for comparison of coal void rehabilitation options, in Proceedings Life-of-Mine 2018, pp 127–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By B C. McLellan

The decline of ore grades on land, increasing demand and high prices for various minerals have led to an increased interest in mining the deep ocean sea floor. The potential deep ocean reserves are vast and in some circumstances the grades are high enough to consider mining. However, the consequences of such mining are as yet uncertain. This paper will present the results of a comparative assessment of life cycle impacts of deep ocean minerals. Two alternative extraction technologies from different deep ocean resource types were examined and key commodities are considered. Initial results indicate that the energy requirements will be higher than the average land-based resources, but may fall within the range of the deepest terrestrial mines.CITATION:McLellan, B C, 2015. Comparative life cycle impacts of deep ocean minerals and land-based counterparts, in Proceedings Third International Future Mining Conference, pp 253–260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By D James

Fletcher Challenge Limited through its subsidiary Grampian Mining Co Limited has carried out an ore evaluation of one of New Zealand's largest known deposits of ilmenite located at Barrytown on the West Coast of the South Island, New Zealand. The ilmenite is located in a beach sand environment which has previously been mined for gold. Two analytical techniques were developed to quantify the resource. Considerable difficulty was experienced in this phase of the evaluation due to the presence of major inclusions within the ilmenite grains. Wet and dry concentration circuits, utilising spiral, wet magnet, high tension and plate electrostatic separators have been designed to produce ilmenite from the ore. Studies to utilise the titanium content of the Barrytown ilmenite have been made. Recent work has been directed towards a titanium dioxide pigment process.

Jan 1, 1986

An Environmental Impact Statement (EIS) for a major mining development typically has to address various aspects of surface water management, including some which generally tend to be the more contentious: the diversion of rivers and creeks from areas disturbed by mining, and their rehabilitation; the effective management of disturbed area run-off via the collection, containment and treatment of contaminated water on site in sedimentation dams; the collection, containment and treatment of mine pit water; the decommissioning of surface water storages; final void water quality; and water discharge criteria. Environmental Impact Assessment processes for proposed mining developments in Australia at the state and commonwealth level usually involve a form of Initial Advice Statement (or Notice of Intent), Terms of Reference, an EIS, and a Supplementary Report (or similar) which responds to agency and public comment on the EIS. The EIS is used by approval agencies to decide the acceptability of the Project, and to set the conditions of approval. The conditions are often in the form of a state-issued æOperational LicenceÆ or similar. With mining, the initial approval at the EIS stage is often just a pre-cursor to various other planning related approvals, including obtaining a mining lease. Afterwards, mine plans and plans of operations must be submitted to government at various stages of the mineÆs life, ostensibly to provide the detailed mine planning over periods of one û five years. Despite all this additional planning and documentation beyond the submission of the EIS, government approval agencies are increasingly not satisfied with conceptual water management designs and commitments to an outcome (such as meeting a specified water quality standard) in the EIS. Agencies are also requiring sufficient water management design information to be convinced that the outcomes are achievable. To assist proponents of major mining developments, the Queensland Government has published Technical Guidelines for water management, and Environment Australia has published a æBest Practice Environmental Management in MiningÆ booklet on water management. In addition, the Australian and New Zealand Environment and Conservation Council (ANZECC. 2000) has published Water Quality Guidelines which provide an approach to water management, and provide receiving water investigation trigger criteria. So, what are the water management issues that are likely to be the subject of comment, debate and negotiation prior to the EIS being approved? and what commitments may a mining proponent have to make in order to convince the approval agencies that sufficient investigation and design has been provided? This paper provides some answers to this question, by reference to recent major mining proposals which the author has managed through state and commonwealth Environmental Impact Assessment processes.

Jan 1, 2003

By A Purwodihardjo

Evaluation of the construction method used for the pedestrian underpass construction at Ipswich Road, Brisbane, Australia is presented in this paper. The pedestrian underpass was constructed through the existing railway embankment between Harrogate and O’Keefe Streets on the eastern side of Ipswich Road. This underpass construction is part of the CLEM7 tunnel project (formerly known as the North-South Bypass Tunnel) which is the longest toll road in Australia at a total length of 6.8 km. The jacked box construction technique was initially identified as a preferred option during the tender and concept design phases. However at the final design stage, the cut and cover technique was selected as this method can reduce the construction time and cost significantly. The design and construction teams effectively managed the challenges, complexities and risks associated with undertaking cut and cover tunnel through the existing heavily utilised rail embankment. The on-site construction time for the underpass using the cut and cover technique was reduced to less than 42 hours.

Mar 8, 2011

Seam correlation in the central Rapahoe Sector (Greymouth Coalfield) can be enhanced by detailed lithostratigraphy and chronostratigraphy. Rewanui Coal Measures are overlain comformably by lacustrine, deltaic and fluvial strata, and this upper contact can be located using lithological and geophysical log character. The Cretaceous-Tertiary Boundary (KTB) occurs near the top of Rewanui Coal Measures and has been identified palynologically in 16 drillholes. The Rapahoe Sector can be subdivided into two palynostratigraphic domains which adjoin along a basement normal fault which was downthrown to the north during coal measure deposition. The KTB provides an isochronous surface which is independent of the lithostratigraphic datum. Using the KTB as a datum, the æUpperÆ, æMainÆ and æSubmainÆ seams can be reliably correlated throughout the southern and central Rapahoe Sector. Similarly, the æSubmainÆ seam can be correlated with æcÆ seam of the Strongman Mine area, though other Strongman seams are absent from the central and southern Rapahoe Sector.

Jan 1, 1996

By D Howe, J Conn, J G. McLellan, K Gates

The Red October Gold Mine, owned by Saracen Gold Mines Pty Ltd, is located approximately 80 km south of Laverton, Western Australia. It is considered to be of a similar nature to many of the Archaean granite-greenstone deposits in the Laverton Tectonic Zone, and presents as an intriguing and relatively young deposit in terms of developed structural and genetic models. Regional deformation events have been proposed for the area, and are relatively well accepted. The most important of these deformation events in the region were the D4b (WNW–ESE sinistral transpression) and D5 (ENE–WSW dextral transpression) which have been attributed to the main Au mineralising phases. At the local scale there appears to have been a rotation of the regional stress field to provide the optimum orientation of maximum principal stress for sinistral movement on the main shear zone.Fully coupled 3D finite element analysis (FEA) was used to simulate the geomechanical response of the system based on structural observations. The geomechanical modelling resulted in highlighting anomalous patterns of stress and strain and subsequent fluid flow as a result of the two main deformation events. The D4 simulation provided a good correlation with the known distribution of subsidiary structures on the main shear zone, and furthermore provided several geomechanical targets that suggested locations of additional subsidiary structures. The D5 simulation provided a great insight into the response of the main shear zone and known subsidiary structures also highlighting additional targets indicating potential for further mineralisation. These targets have since been followed up with a 732 m deep surface reverse circulation (RC) drill hole, resulting in the discovery of two high-grade shoots, with follow up testing currently planned for mid-2014.CITATION:McLellan, J G, Conn, J, Howe, D and Gates, K, 2014. Structural controls and strain partitioning in the Red October Gold Mine, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014 , pp 315–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Thomas E. G

In the economic evaluation of any Australian mining project, changes in taxation can significantly affect viability. Australian tax laws, particularly in the period since early 1973, have undergone many changes which have led to shifts in the profitability of mining companies. This paper examines the sensitivity of a selected, broadly based sample of Australian mining companies to the changes that have occurred, or are reasonably likely to occur, in taxation legislation. In the past, tax systems have been altered for a variety of reasons, such as 1. reduction'in the impact of inflation 2. neutralization of incidence between different sections of the economy 3. as an incentive to encourage expansion and growth in a particular industry or area, and 4. increase in the real "take" of government. In this paper, conventional rate of return analyses are applied in a study of how profitability is affected under various taxation systems.

Jan 1, 1977

By B P. Banerjee, D Patra, S Raval

Roof bolts are an essential component of roof support systems in underground mines. They are used to provide structural support to the roof of the mine and prevent it from collapsing. Therefore, it is imperative to perform regular assessments of these roof bolts to avert any hazards. Manual investigations of roof bolts are done by surveyors in underground mines, which is extremely timeconsuming and challenging due to the low-light conditions in underground mines accompanied by stringent mine access rules. To this end, automated recognition of roof bolts in 3D point cloud data obtained through laser scanning in underground mines serves as a potential solution to aid roof bolt monitoring. With the continuous advancements in laser scanning-based 3D data acquisition systems, the feasibility of making such surface estimations from 3D point cloud data has increased severalfold.

Sep 1, 2024

By Alwan M

At Binebase mineralisation is hosted within an andesitic Neogene volcaniclastic succession on Sangihe Island, Indonesia. Two major alteration types occur; an initial widespread phyllic assemblage of quartz -illite with chlorite, smectite, gypsum and pyrite, and a superimposed quartz - barite - sulphide assemblage. The phyllic alteration arose from a neutral to weakly acidic hydrothermal solution of greater than 200 degrees C, and the quartz - barite - sulphide assemblage arose from a cooler slightly more acidic fluid. This second alteration event is interpreted to have selectively replaced permeable volcaniclastic breccias and coarse lithic tuffs within the altered sequence. Gold and silver mineralisation is associated with the latter alteration, and is locally controlled by the degree of silicification and sulphide abundance. The sulphides present are pyrite, covellite and chalcopyrite. The sulphides are very fine grained with colloform and framboidal textures and were deposited contemporaneously with the bulk silicification of the coarse sediments. A large portion of the mineralised rock has been oxidised to a quartz - barite -limonite - goethite - jarosite assemblage.Coincident gold, silver and antimony geochemical soil anomalies gave the best correlation with anomalous gold and silver grades in bedrock as identified by drilling. Resistivity proved a reliable geophysical method for delineating zones of silicification.

Jan 1, 1990

By R Strand, B Usher

Environmental compliance and mine designs are increasingly including assessment of flows and water qualities as a key driver to decision-making over life-of-mine. Integrated site-wide water quality models linked to dynamic water balances have been used for regulatory submissions, feasibility studies, operating mines and mine closure studies. These models, developed in GoldSim, link aqueous chemistry to the physical system of the site-wide water balance. Geochemical mechanisms included are determined from geochemical characterisation and site water monitoring, depending on the data availability at each site. External geochemical modelling using PHREEQC, version 2 (by D?L?Parkhurst and C?A?J?Appelo) and Geochemists Workbench (GWB), (by C?M?Bethke and The Board of Trustees of the University of Illinois) identifies the most important geochemical processes to be included in the model as a series of geochemical mechanisms which include source term loading rates, pH-buffering and equilibration of water quality. Water balance components include seasonal flow variability; waste facility water storage and system lags; run-off variability; milling processes and tailings production as a function of ore types; simulation of automated and scheduled maintenance of settling ponds; water re-routing for water treatment and freshwater demand, usage and storage.Case studies illustrating the use of these models for regulatory submissions and mine feasibility studies in a variety of climatic and regulatory environments show the utility and applicability of these models. Site-specific examples of these models developed by Klohn Crippen Berger Ltd are currently used at operating mines across the world. One of the larger mines where this is used is a mature poly-metallic mine in South America where the model has aided mine managers in understanding how various planned initiatives and potential water options will result in changes to flows and water quality. It is used regularly to inform water and waste management to minimise impacts to the receiving environment as a consideration of both flows and concentrations. The mine has also used the model in support of water treatment design, regulatory submissions and mine closure planning.Further examples of feasibility and operational/compliance assessment in arid and strongly seasonal environments for planning, regulatory and closure consideration of mine wastes and pits have shown the utility and usefulness of these approaches for a range of mining operations at various stages of mine life.CITATION:Strand, R and Usher, B, ?2014. Integrated site water balances and water quality models for decision-making over life-of-mine, in Proceedings Life-of-Mine 2014 , pp 271–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By A Jha, R Merz

The substantial growth in world demand for Queensland coking coal has seen a number of new coal mine developments in the Bowen Basin in recent times. The Bowen-Broken Water Supply Scheme (BBWSS) is presently based on water supplied from Eungella Dam and storages at Collinsville to two major pipelines. In early 2004, three successive years of well-below average rainfall had left Eungella Dam at critical levels, threatening the regionÆs mines, which rely on it for their essential water supply. SunWater noted that without significant inflows into Eungella Dam, or the development of a new water supply to the region, existing mines would be severely restricted in water supply, and downstream economic impacts to the region would follow. SunWater investigated the opportunities for additional supply capabilities, including combinations of off-stream storages, additional pipelines, and raising Eungella Dam. An off-stream storage (OSS) was selected as being the preferred option to improve the reliability of the system and head off impending falls in announced allocation for the system. The integrated quantity quality model (IQQM) is the Queensland GovernmentÆs preferred model to define and assess total catchment performance against water security and environmental objectives. Modelling of the performance of the water supply system, with and without the proposed OSS, was required to provide justification to the customers of the system that the OSS was in fact required, and also to optimise the configuration of the OSS within time and budgetary constraints. In the case of the BBWSS, no environmental base flows are dictated by the Department of Natural Resources, Mines and Water (NRM&W) at present and the primary reason for applying IQQM was therefore to investigate the trade-offs between supply options and reliability. SunWater produced IQQM outputs for a range of scenarios for the proposed off-stream storage, and these IQQM outputs were then used as input to a decision-support tool based on the GoldSim modelling package. The GoldSim model was then applied to investigate the water supply reliability for high priority users resulting from various existing and/or proposed water supply infrastructure configurations coupled to the hydrologic system. The GoldSim model included the ability to assess the long-term water supply reliability impacts for each of the water supply end-users for a wide range of user-defined scenarios. Non-technical model users were able to change the size of the off-stream storage, pipeline capacities and assumed climatic conditions and test for themselves the relative benefits (in terms of water supply reliability) of different infrastructure configurations under consideration. The decision tool was of significant benefit in assisting the decision process to SunWaterÆs mining customers. These customers needed to decide if they felt that the increased reliability in their water supplies from the system that would be created warranted the estimated increased charges that would require to be levied to recover costs of the new infrastructure with appropriate profit margins. The conjunctive use of IQQM and GoldSim was successful in demonstrating the impact of both hydrological and non-hydrological issues on the future water supply reliability in the BBWSS and resulted in a decision to proceed with the construction of a new OSS.

Jan 1, 2006

By S Coward, S Jackson, S Moayer, J E. Vann

The variability and uncertainty of mineralisation, coupled with subsequent uncertainty in mining and processing, is often paid scant regard or overlooked during the evaluation of mining projects. In many instances, when the project transitions to the operational phase, the reality of feed or product variability and the consequences of unquantified uncertainties throughout the value chain become obvious. The outcome is the familiar picture of frequent ramp-up underperformance and failure to deliver on planned targets and objectives.Both mine and exploration geologists are expected to generate mineral deposit models that are based on an integration of diverse sources of data. These multifaceted deposit models already play a pivotal role in the design, development and optimisation of mining project value, and the trend to a fully digitally engineered future means that this importance is increasing. It is therefore vitally important that tools be made available to the geologist (as well as mining engineers and metallurgists) that enable them to characterise and assess variability and uncertainty via appropriate deposit models and thus articulate their impact on potential project configurations and decisions. Scenario-based project evaluation (SBPE) provides a framework for full and proper analysis of the downstream impacts of inherent deposit variability and uncertainty on project performance.SBPE has been developed by the authors over several years and aims to propagate geological uncertainty and variability through the mining value chain. The outcomes of SBPE can be tested against future external scenarios capturing financial, economic and socio-political factors that also drive project performance. Stochastic representations of the orebody (via conditional simulation (see Chilès and Delfiner, 1999)) that explicitly incorporate variability and represent uncertainty are propagated through the value chain on a block-by-block basis (ie on a much more granular basis than traditional project evaluation approaches).Conventionally, metallurgical processes are modelled with deterministic equations (eg regression models) based on limited data. The SBPE approach allows for the modelling of process performance uncertainty using geometallurgical sampling fully. Multiple outcomes of SBPE are passed through financial modelling, which can also incorporate stochastic components, thus allowing full quantification of the risks and opportunities of a set of project alternatives. The value of the SBPE system is that once a base case has been established, multiple engineered alternatives coupled with external scenarios are easily evaluated and compared in terms of incremental value.A new case study of SBPE is presented that shows how, by analysis of the various aspects of variability and uncertainty, project managers are able to focus on the areas that have the greatest ability to reduce risk and/or add significant value. This can lead to sufficient flexibility being built into operations that allow operators to cope with the real orebody delivered to the plant.CITATION:Jackson, S, Vann, J E, Coward, S and Moayer, S, 2014. Scenario-based project evaluation – full mineral value chain stochastic simulation to evaluate development and operational alternatives, in Proceedings Ninth International Mining Geology Conference 2014 , pp 21–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By B Xiao, J Yang, H Chen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Tuwu-Yandong Cu deposit, located in the East Tianshan mountains in the eastern section of the Central Asian Orogenic Belt, is the largest and economically most important porphyry Cu deposit in Xinjiang, China. It contains ~3 Mt of copper at an average grade of 0.46 per cent Cu and 0.2 g/t Au, with significant amounts of Mo and Ag. The deposit is mainly hosted in the Carboniferous Qi’eshan Group and plagiogranite porphyry, and is controlled by faults that are east–west-, north-west- and north-east-trending. Ore minerals in the Tuwu-Yandong deposit are dominated by pyrite, chalcopyrite and molybdenite, with minor bornite, chalcocite, magnetite, sphalerite and galena. Gangue minerals are mainly composed of quartz, sericite, chlorite, epidote, anhydrite, gypsum, muscovite, biotite, phosphorite, sphene, dolomite, actinolite, barite, albite and calcite. Based on the megascopic and microscopic textural relationships and mineral assemblages, five stages of hydrothermal alteration and hypogene mineralisation are recognized in the Tuwu-Yandong Cu deposit: the potassic stage, propylitic stage, phyllic stage, late veins stage and supergene stage. Most of the copper was deposited during the phyllic stage, along with less molybdenite.CITATION:Xiao, B, Chen, H, Wang, Y and Yang, J, 2015. Geology, mineralisation and alteration of the Tuwu-Yandong porphyry Cu deposit, north-west China, in Proceedings PACRIM 2015 Congress, pp 641–644 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By R A. M Maddever, P Jeanneau, V Flahaut

Over the entire life cycle of a mine, from early resource evaluation to the blasting of benches, the collection of geochemical data is crucial for the site operator, who must routinely and intensively drill and sample the orebody. This produces huge numbers of physical samples, in turn requiring significant cost and time for their preparation and assay. Moreover, despite best efforts, the sample recovery process is prone to error, which limits the quality of data.The pulsed neutron gamma technique has been used for decades in various industries, in particular oil logging, for its ability to provide direct identification and quantification of elemental concentrations. However, its implementation in logging tools for the mining sector is relatively recent. Built around the latest in technology for optimal spectrometric measurement, a commercial tool referred to as FastGrade™ 100 has been available for a few years and used with increasing success in the mining environment, specifically the iron ore industry, resulting in a reduction in the amount of collected samples. Relying on the physics of neutrons and gamma photons, both of which are particles that penetrate the surrounding bedrock through several tens of centimetres, such spectroscopy tools measure in real-time the composition of a much larger volume than the delimited volume of the drilled material traditionally used for geochemical mapping. Better statistics and reliability of the estimated composition increase the ability to properly and quickly measure drilled holes and allow the substituting of all or part of the sampling and assaying efforts by geochemical log data. Our paper focuses on this technology, known as pulsed fast and thermal neutron analysis (PFTNA). It reviews the main drivers for the design of such a logging tool and discusses how the fundamental characteristics of the technology, in terms of neutrons and gamma interactions, translate into interpretation of the analytical output.CITATION:Jeanneau, P, Flahaut, V and Maddever, R A M, 2017. Iron ore benefits from neutron pulsed geochemical tools, in Proceedings Iron Ore 2017, pp 387–396 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

With the launch of Immersive Technologies' next generation of Advanced Equipment Simulators for the mining industry, correlating and influencing safety, productivity and maintenance with operator competency improvements is now made even more effective. In early 2008, Immersive assembled a project team to investigate the potential linkages between operator competency and performance. Advanced Equipment Simulator Users with a range of sophistication were interviewed and consulted. The result was new and enhanced 'value realisation' programs to directly assist mine sites to deliver the expected return on investment (ROI) from simulators and operator competency development. In just over one year, 29 mine sites around the world have benefited from 34 completed programs. Case studies have been compiled to demonstrate the impact of the implementation of this approach, including at the following operations: Anglo Coal - Callide (Australia), Freeport McMoRAN - Grasburg (Indonesia), Equinox Minerals - Lumwana (Zambia), Peabody Energy - Cabllo (USA), and Xstrata - Lomas Bayas (Chile). Significant performance improvements have been achieved including: reductions of 47 per cent in gear shifting and 37 per cent in over speed errors, improvements of 68 per cent in park break errors and 12 per cent in spotting time, and increase of 54 per cent in passing emergency fire handling competency tests. This presentation draws on these case studies to clearly demonstrate the linkage between improved operator competency through the implementation of training programs tailored around Advanced Equipment Simulators and production performace measured by a range of standard metrics at mines around the world.

May 1, 2010

By J Krawcz, S Wasilewski, W Mironowicz

Barometric pressure and its variation in deep underground workings have a considerable effect on ventilation conditions. Pressure changes which create transient states of air flow and air parameters in workings are especially significant. Experiments have shown that pressure changes have a remarkable effect on air parameters at mine workings and hence, attempts to evaluate the scale of this phenomenon are of value. Continuous monitoring of the barometric pressure on the surface of mines allows for the detection of changes in pressure which undoubtedly influence alternations of pressure in the underground areas of mines. Very important factors are the internal disturbances of pressure within a mine ventilation system due to variable conditions of fan operation and the operation of a winding machine where a mine cage moving in a shaft causes piston like disturbances. Local transient disturbances caused by temporary opening/closing of air stoppings due to personnel or underground transport traffic are of importance. The results of over two years of observations of barometric pressure and its influence on pressure variation in underground mine workings are presented in this paper. The observations were possible through the installation of pressure sensors at selected points of the downcast shaft in a mine. Of interest are the observations of the transient states of pressure and other air parameters caused by emergency fan stoppage, movement of a mine cage and changes due to the opening of air stoppings. Data acquired during experiments of opening and closing air stoppings were used for the validation of a flow model in a long working.

Jan 1, 2005

This paper is for mine managers. It is about maintenance of mining equipment. This is an extremely broad subject so this paper is given with the caveat that it necessarily contains generalisations, not true in all cases, but broadly correct. The job of mine managers is to be good at making money from the excavation and preliminary treatment of mineral. To do this well, they need to understand the cost and value drivers in the business. This includes understanding the drivers associated with maintenance. Maintenance is often identified as a problem at mine sites. It is frequently listed as the cause of production shortfalls when reporting. The state of maintenance within mining as an industry is generally among the lower end of the range, when compared to manufacturing, petrochemicals, etc. Why is this? Experience and review of many audits and evaluations of maintenance has shown that some patterns are consistent with good performance and some consistent with poor performance. These often centre around the time horizon of the management team and are associated with knowing the sensitivity of the business to certain maintenance drivers and the mechanisms of maintenance and their results. To summarise, some common misunderstandings can be listed as statements that are obvious and extrapolations from those, which are not necessarily correct. For example: High availability of equipment is necessary for production. Incorrect extrapolation:focus on availability will produce high production. Design is often the greatest factor in determining the reliability of a mining machine. Incorrect extrapolation: the newest and biggest machines generally have the lowest cost operations. Operation has an enormous impact on machine productivity and reliability. Incorrect extrapolation: the fastest operators are generally the best from a productive point of view. Some maintenance improves the performance and reliability of machines. Incorrect extrapolation: more maintenance will give you more reliability. Some maintenance depends on disassembly and reassembly of components. Incorrect extrapolation: assembly is basically the reverse process of disassembly. Maintenance improvement in the mining industry in the last 15 years has focused largely on planning and systems improvement. Incorrect extrapolation: most of the problems in maintenance can be traced to a lack of planning. Actions based on flawed extrapolations will steer a business suboptimally. It is therefore important that the mine manager understands these issues so that the improvement effort can be directed to the greatest benefit.

Jan 1, 2006