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By J Light

Since 2019, the mine planning team at Olympic Dam has been establishing and maturing a shift from deterministic to probabilistic scheduling techniques. This paper outlines this journey undertaken by the mine planning team, key learnings from implementation and further work required to increase the level of planning maturity. Olympic Dam (OD) is a highly variable, polymetallic orebody with a vertically integrated value chain from operations to final product. The processing plant has a tight set of quality constraints which are managed through timing of stopes from varying parts of the orebody. Value is eroded for the operation when forecasted quality of the mine feed encounters disruptions from unplanned changes to the timing of stope starts. As production has moved from the historic Northern Mining Area into the more geologically complex Southern Mining Area, average stope size has reduced, resulting in increased mining fronts required to meet production targets. This has created a problem of increased schedule complexity and difficulties in identifying and communicating resource priorities within a large set of individual stope critical paths. The problem was approached by considering each stope as an individual project constructed by teams working across multiple projects at any one time. The operation could then be considered a multi-project environment with shared resources and enables the application of Critical Chain Project Management (CCPM) to the mine plan. Key to CCPM is the addition of time buffers to protect the critical path of a project form upstream or downstream processes. Implementation of time buffers protects the stope start date against compliance to plan variance. The monitoring of each time buffer consumption, as a proportion of total construction activities completed enables proactive prioritisation of resources. This resulted in an increase in the number of stopes starting in accordance with the mine plan, simplified communication of priorities to all levels of the operation, increased compliance to plan and a clear measure of schedule risk during planning routines.

Mar 29, 2023

By F Burns, G Peachey

The Hidden Valley process plant has recently undertaken a program to relieve process flow bottlenecks and improve process automation. An environment of cost reduction and restrained capital necessitated solutions that primarily utilised existing equipment and internal resources. Removing bottlenecks relieved pressure from a strained circuit that was unable to maintain consistent performance. Improved process automation firstly stabilised the process, then allowed the circuit to sustainably operate at the expanded capacity limits. These allowed implementation of an operating approach that focused process operators towards identifying and resolving process disturbances in advance. Plant recovery and throughput have markedly improved as a result.CITATION:Burns, F and Peachey, G, 2014. Recent process improvements at Hidden Valley gold mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 43–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By T Ladinig

Raise caving is a novel cave mining method, which has been proposed for mass mining at increasing mining depths in LKAB operations. The method makes use of the raise mining technology and an active stress management approach. For the implementation the method is split into two phases, namely a de-stressing phase and a production phase. In the de-stressing phase, a slot-pillar system is established. The purpose of slots is to provide stress shadows and the purpose of the large pillars is to control stress and seismicity. The production phase follows after the de-stressing phase. Required infrastructure in the production phase is developed delayed in stress shadows and bulk extraction takes place in de-stressed zones. Eventually the pillars crush and they are extracted in the production phase. A comprehensive research and development program has been launched to develop the raise caving method towards implementation. As part of this program a full-scale test site of raise caving will be conducted as well as raise caving operations are planned for depth extensions in LKAB mines. This paper discusses the design of raise caving operations in practice at the LKAB mines. In particular, the purpose of the paper is to focus on requirements for the development and design of a raise caving operation. The development of raise caving is discussed from a systems engineering perspective as well as from a management perspective. The functional requirements in the destressing and production phase are outlined and discussed in the paper. The discussion is on basis of the main elements of the raise caving system, such as slots, stopes, pillars and infrastructure. Critical rock engineering design requirements in the de-stressing and production phase are highlighted and dependencies between individual main elements are identified. The analyses show that pillars are especially important for the success of the mining method. Overall, the analyses show that raise caving is a complex system and that its development demands a multidisciplinary approach.

Mar 29, 2023

The offshore Maui gas/condensate field was discovered by Shell BP and Todd on Services Limited in 1969. Subsequent appraisal drilling and negotiations with the Government led to a development agreement, æThe Maui White Paper' being concluded in 1973. Part of this agreement provided for the Government to take a 50 per cent shareholding in the field. The field is comprised of a double domed anticlinal structure containing two gas reservoirs at depths ranging from 2700 - 3000 m. Water depth is 110 m. The development plan called for two standalone steel platforms to be installed sequentially over a period of some years depending on gas demand. The first platform (MPA) was put in place in 1976 but difficulties were experienced with piling and drilling of the 12 (later increased to 14) wells did not start until 1978. First gas was piped ashore late in 1979.

Jan 1, 1994

By B Murphy, N Strong, J Albrecht

Rio Tinto’s Argyle Diamond Mine has a history of underperformance with delivery of ore from the underground operation to the surface for processing with no real clarity in sources of loss and value. In order to increase underground production performance, the basic concepts of the Theory of Constraints model were applied to the Argyle underground production system. This prompted a revised view on bottlenecks and contributors to value loss and ultimately leading to record breaking mine performance. System loss reporting to demonstrate the best opportunity to drive value, departmental detail to develop tools to identify improvement opportunities and clarity across the team to ensure alignment and clear lines of communication were critical to the project success.

Mar 15, 2021

By J E. Powalisz

Obtaining a representative sample of bulk materials in process industries is critical to providing valid data for process control and custody transfer (valuation). The accuracy of a sample, that is to say how well the sample represents the material in the process, is directly related to how well the process can be controlled and to how much a product may be worth. Sampling accuracy then is in fact related to bottom line profitability.Sampling theory offers information and equations on how to take a representative sample from a process, however, the actual practice of extracting a sample from the process can be more of an art.Key sampling variables include product specifications such as bulk density, particle distribution, material conveyance, practical sampler location, sampler type and sample frequency and volume/mass.This paper discusses basic sampling theory, sampling methods, types of samplers, how to develop a ‘real world’ sampling system and current manual and automated samplers.Key points include ‘practical precision and variance’, material properties, flow properties, direct sampling versus indirect sampling, sampler types and applications.CITATION:Powalisz, J E, 2014. Bulk solids sampling, in Proceedings Sampling 2014 , pp 179–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By Baafi EY, Sun Y, Tague I

Field trials at three New South Wales and one Queensland coal mines were carried out to gather data on oxygen "run out" times of Self-Contained Self Rescuers (SCSRs), time taken to escape from the mine, distances travelled and the average heart rate of subjects wearing SCSRs. The study has led to a method of predicting the duration of oxygen supply from a SCSR as a function of the wearer's body weight, physical fitness and the prevailing environmental conditions. Escapeway design, planning for emergencies, familiarity with SCSRs and experiential escape training are critical to control panic and maximise the likelihood of survival of a person attempting to escape in an emergency involving fire or explosion.

Jan 1, 1998

Process variables in flotation circuits are outlined with a view to producing mathematical models of circuits. The nature of the kinetics of flotation are discussed and the effect of process variables on the kinetics considered. An approach for a possible model is briefly outlined.

Jan 1, 1971

By T Walkemeyer, R Elliott, D Chang-Martin

Over the past decade, discrete element method (DEM) simulations have seen increasing adoption by the resources sector to inform the design of materials handling equipment such as transfer chutes, bins and hoppers. But, if ‘all models are wrong, but some are useful’ (Box, 1979) what approaches are available to check that a DEM simulation is useful? How to avoid garbage in equals garbage out. This work considers what properties of bulk solid flow behaviour are important to transfer chute simulation. Cohesive bulk solids (such as sticky iron ore fines) can develop sufficient strength to form a stable cohesive arch, this phenomenon is not well predicted by measurements of angle of repose. This work presents a two-part approach to the development of a useful DEM model that can be used to add value to the design and optimisation of bulk materials handling equipment. Part 1 is the calibration of not just one, but a range of material models chosen to envelope the range of anticipated materials that will be handled. This work describes the DEM simulation of a batch of direct shear cell tests to develop material models that can be measured by the same metrics routinely used to characterise the flowability of cohesive iron ore fines. Part 2 of this work describes systematic methods for validation of the transfer chute DEM simulations. The DEM model is only useful if it can adequately represent the typical problems observed within a transfer chute, such as blockages due to build-up and cohesive arching. Proper validation requires good observations. Validation examples of site observations are shown side-byside with simulations to demonstrate the adequacy of the DEM model and calibration approach. DEM simulations have the potential to add significant value by allowing engineers and designers to predict material flow-through equipment based on a range of material properties, allowing for stress testing designs and making iterative improvements.

Sep 18, 2023

By S Mitra, D O’Dea, N Barrett, T Honeyands, P Zulli

The steel industry continues to explore and demonstrate technologies that decrease its greenhouse gas emissions, especially in blast furnace ironmaking where alternate operating conditions will be required. As the furnace has been optimised over many years, it is approaching the minimum fuel rate possible with coke and Pulverised Coal Injection (PCI). Alternative operating conditions are therefore required to further decrease greenhouse gas emissions. Because of this, hydrogen has been proposed as a reducing agent in the blast furnace. Injection of hydrogen through the tuyeres was assessed using a comprehensive 2D blast furnace global model. The model was calibrated to a blast furnace operating with PCI as a base case and various approaches to hydrogen injection assessed, with a particular focus on displacing PCI. The maximum hydrogen injection rate of 19.5 kg H2 per tonne of hot metal was predicted, limited by decreases in the raceway adiabatic flame temperature and top gas temperature. Internal blast furnace conditions, such as gas composition and reduction degree were also predicted. Holistic analysis was performed to estimate the effectiveness of hydrogen injection on reduction of greenhouse gas emissions. Based on these results, the changes in blast furnace operation and emissions under hydrogen injection are discussed.

Nov 8, 2021

By A Noack

Today underground infrastructures, like tunnels and especially wide spread underground mines, are often equipped with ethernet based communication systems. These networks are used for the unified communication of data, voice and video. As these networks stretch along the major tunnels and in increasing scale also into the production areas, a high degree of coverage can be reached. For wireless coverage, standard IEEE 802.11 WLAN access points are being used. In order to provide a maximum availability and reliability, the active components are equipped with battery backup power supplies and the network infrastructure is set up in a redundant way using ring or meshed topologies. This provides a much higher availability compared to traditional phone systems or dedicated data links using a conventional star topology.Distributed computing intelligence that is installed on active network nodes throughout the whole network, additionally supported by a central server system, creates the basis for new mine safety functions introduced in this paper for both coal and non-coal mining. These new safety functions cover the detection of potential emergencies, using the status of the network as a æsensorÆ, as well as dynamically guiding people to safe exits or rescue shelters in case of an emergency. Furthermore, these functions are of important benefit for improving the efficiency of search and rescue operations following a major incident or accident underground.

Sep 26, 2011

By M Nagarajan

Orica Mining Services (Orica) in partnership with Coal and Allied’s Hunter Valley Operations (HVO) has developed a risk management process to maximise mining efficiency whilst controlling vibration and maintaining critical electricity continuity to New South Wales (NSW) electricity grid in the Riverview Pit. The issue is a high tension tower which supplies electricity located within 40 m of mining and blasting activities. The process involved developing an understanding of the relationship between vibration, explosives, geology and the location of the blasting in the geological horizon. From this an optimum methodology for blasting in each region was developed.

Nov 8, 2011

By J Player, R de Vries, J F. Carswell, R Hassell

"The feasibility of Dugald River mine was highly sensitive to mining and geotechnical design assumptions, particularly stope dilution and strike length. Following the start of initial mine development in 2012 the project was suspended in 2013 due to concerns over the complex ground conditions and resulting dilution, stope sizes and general mineability. A technical risk mitigation program was undertaken with a key aim to increase the level of confidence in predicting stope dilution.A stope sizing and dilution model was developed that provided a range of stope sizes based on geotechnical conditions and acceptable dilution. The original feasibility used a standard stope size of 25 m height by 25 m span. The new model was used as the foundation for the subsequent updated development plan for Dugald River that reduced much of the previous technical risk through greater confidence in the geotechnical and mining parameters.Several methods to predict stope hanging wall dilution and appropriate stope size have been used at Dugald River that relied on the modified stability graph method. Improvements to the method were identified as more rock mass and mining data became available through the completion of a trial stoping program, increased underground development and a large geotechnical core logging campaign. These improvements not only focused on the technical aspects of the model, but also on creating an easy to use and sustainable process that could be used at multiple stages of mine planning from life-of-mine (LOM) through to final stope design.Several of the main improvements are: understanding stope failure mechanisms and collecting only geological information that is most relevant detailed modelling restricted to the rock mass that could be expected to influence stope behaviour accounting for different stope failure mechanisms with the stability chart method assigning a geotechnical confidence factor to the data making it useful as a mine planning tool with integration into the mine planning process using performance of completed stopes to update and calibrate the model.The model provides recommended hydraulic radius and associated dilution estimates across the ore body. Providing the hydraulic radius allows planning engineers the option to consider single, double and triple lift stoping options suitable to mine scheduling. While the model has been calibrated for conditions at Dugald River the process used to create the model is not site specific and is applicable to other steeply dipping tabular orebodies.CITATION:Hassell, R, de Vries, R, Player, J and Carswell, J F, 2017. Improving the prediction of stope hanging wall dilution – a critical factor to the success of Dugald River, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 71–78 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By C Armstrong, B Wentzinger

Upstream embankment raises often represent the lowest cost option for increasing the capacity of tailings storage facilities (TSF), but also pose the highest stability risk due to constructing on top of previously deposited tailings.This paper presents an overview of key aspects in the geotechnical investigation and design of upstream raises and some recent lessons learnt from experience across a number of TSFs in Australia. A summary of recommended field investigation and laboratory testing methods is provided with a focus on collecting quality information for design purposes. A strong focus is given in developing an accurate assessment of pore water pressures, which, if not correctly understood can have disastrous consequences on tailings strength parameter interpretation and wall stability assessment in static and post-seismic conditions.The assessment of the contractive or dilative shearing behaviour of the tailings material and rigorous interpretation of design characteristic values are presented. Some comments on stability analysis options and proposed methodology are also provided.CITATION:Wentzinger, B and Armstrong, C, 2018. Lessons learnt in geotechnical investigation and stability analysis for upstream tailings storage facility raise design, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 333–348 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

Constraints on the mineral industry are best treated as issues that have to be understood and managed in partnership rather than in conflict with communities. The Zapopan development at Mt Todd in Australia and the Martha Hill development at Waihi in New Zealand are but two of many recent successful examples at the local level. However, at the national level, the issues are more complex and more difficult to resolve because the most influential stakeholders are now the urban electorates and governments defer to their perceptions when making decisions and policy.

Jan 1, 1995

By Hunter W. H, Wilson I. P, Craig R. W

In September 1988 the Imperial Smelting zinc - lead blast furnace at Avonmouth England, was uprated from its then 52 week annual rated capacity of 90 000 tonnes/year of furnace zinc to 110 000 tonnes. In order to provide sufficient extra feed the sinter plant was likewise uprated in April 1989 by increasing the blowing rate of the sinter/acid plants from 100 000 to 120 000 Nm3/h, effectively a 20 per cent increase. In the 12 months after the uprate zinc production was only 85 000 tonnes. Two years after the uprate zinc production had increased to 100 000 tonnes, but it was not until January 1992 that a rolling 12-month zinc production of 110 000 tonnes was consistently achieved. This paper describes the problems encountered with the uprate and how they have been or are being overcome. It deals chronologically with events starting with the restart of the ISF at the end of 1988 and covers the following issues and their resolution: 1. Initial shortages of sinter due to an offset in uprate timing. 2. Greater difficulties in operating the larger furnace particularly on start-up, the greater tendency for iron production and serious slagging problems. 3. Coincidental timing of deleterious trends in slag chemistry. 4. Refractory problems in the furnace shaft and condenser. 5. Shortages of sinter due to commissioning problems with the wet gas and sinter tip end fans, and difficulties in obtaining sufficient sinter hardness. 6. Unrealised full benefits of the sinter-acid uprate due to a late change in design to dispense with sinter gas recirculation, but offset by successful use of oxygen. In a planned maintenance stop in September 1992 further improvements to the furnace design were carried out to resolve the refractory problems, and with improvements to the sinter plant the furnace zinc output capacity is planned to rise to a rate of 120 000 tonnes/year within two years.

Jan 1, 1993

By M Dusci, A Trueman, S Poos, R Baumgartner, M Brittan

The Canahuire epithermal Au-Cu-Ag deposit in southern Peru is a complex and challenging deposit for metallurgical studies. It has issues of gold locking in sulfides and non-sulfides, deleterious elements and acid rock drainage (ARD). From scoping study to feasibility study, there has been considerable improvement in the understanding of the important geometallurgical characteristics that need to be measured and modelled. This paper presents the current understanding and the requirements to continue to provide optimal models for mining studies.Significant effort has been put into understanding the genesis of the deposit. Improved spatial and temporal understanding of lithology, alteration, structure and mineralogy was used to build a geological and alteration model of the deposit.Early metallurgical programs quantified the effect of head grade on process plant recoveries, but the geometallurgical and statistical analyses did not identify other physical characteristics that influence these recoveries. The studies improved the understanding of the nature of locked gold which can occur as minute inclusions (< 5 ¦m) in sulfides (primarily pyrite with lesser arsenopyrite, pyrite being 100 times more abundant than arsenopyrite) and gangue minerals (quartz and carbonates) as well as solid solution in arsenopyrite and pyrite.The presence of pyrite and the limited buffering capacity of waste rocks increases the potential ARD, which will require mitigation costs before, during and after operations. Waste rock ARD potential has been classified and incorporated in the geometallurgical model. The current classification of waste rock at Canahuire, using international classification standards, is limited due to the complexity of the deposit.Complex deposit metallurgy necessitates a complex process flow sheet, including flotation and cyanidation. Economic recovery will be constrained by the relationships between economic variable grade, other elements and mineralogy. These constraints and inter-relationships are difficult to establish throughout the deposit with a single test. A follow-up geometallurgical program is under investigation and will attempt, with the help of additional test work, to map areas of higher and lower recoveries. It is hoped that metallurgical response can be linked to measurable parameters other than head grade. If this is possible, these factors can be incorporated into future geometallurgical models.CITATION:Baumgartner, R, Dusci, M, Trueman, A, Brittan, M and Poos, S, 2013. Building a geometallurgical model for the Canahuire Epithermal Au-Cu-Ag Deposit, Southern Peru - past, present and future, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 51-58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Stevenson BG

The relevance of ore-dressing mineralogical investigations to developing and improving metallurgical flow-sheets is discussed and examples are given of the application of such studies to various types of ores and mill products (Au, Cu-Sn, Ni and Sn). The mineralogical investigations described illustrate (a) assessment of the feasibility of ore pre-concentration by heavy-media cyclone separation, (b) evaluation of the potential applicability of various metallurgical treatment processes to an ore, and (c) characterization of mill products to assess circuit efficiency and to guide circuit modifications.

Jan 1, 1978

By I Grewal, B Klein

The Knelson Continuous Variable Discharge (CVD) is a continuous centrifugal gravity concentrator for high-mass yield recovery applications. It has four operating variables that enable control of mass yield, product grade and recovery namely: fluidisation water, bowl speed, pinch valve open time and pinch valve closed time. Plant testing of a pilot scale Knelson CVD6 was conducted to evaluate the effects of operating variables on mineral separation. The analysis of operating variable effects has provided a framework for the development of operating guidelines for the CVD.

Jan 1, 2001

The Hishikari gold deposit, discovered by the Metal Mining Agency of Japan, has become a giant class epithermal gold deposit with the highest grade of gold yet recorded in the world through detailed exploration and development by the Sumitomo Metal Mining Co., Ltd. The exploration strategy involved a regional approach combining geological and gravity surveys over a 900 km2 area which had historically produced over 120 t of gold. These surveys were carried out to grasp the common geologic features of epithermal gold deposits in the survey area. A genetic model for epithermal gold deposits in the area under regional survey was also considered based on detailed research of the Kushikino epithermal gold deposit which was in operation at that time. This model was applied to the targeted areas, and important relationships between mineralization, host lithology, intensive propylitic alteration and gravity highs became apparent. The Hishikari block was selected in this way and bonanza gold was discovered during drilling. Since the development of the Hishikari mine, information useful for further exploration for the same type of deposit has been accumulated.

Jan 1, 1995