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By E Williams

The role and importance of a well designed test work program during the development of an orebody is often underestimated. A test work program should be tailored to deliver very specific answers to relevant questions. With a clear purpose, the results from the test work program will enhance the outcome of the feasibility study and provide the information required to meet the requirements of all stakeholders. With regard to test work programs there are three main areas that should be considered: orebody characterisation and definition, process flow sheet development and engineering design information.Orebody definition relies on reliable analytical methods to characterise and assess the economic minerals present in the ground. In mineral sands, the physical processing characteristics of the minerals play a significant role in the definition of an orebody. The analytical method therefore has to be customised using a combination of laboratory techniques. These techniques can include heavy liquid separation, gravity separation and magnetic separation and are usually combined with chemical and mineralogical analyses to create a picture of the orebody. During the definition phase of test work programs, an appropriate analytical technique has to be developed to evaluate drilling samples, but also to support the information collected during flow sheet development.Process flow sheet development is usually done once there is a reasonable understanding of the size and variability of the orebody. Selecting the best sample for test work is critical, as any flow sheet design is tied to the specific characteristics of the sample used for development. There are other factors that can improve the outcomes of flow sheet development test work, including the skills and knowledge of the operator and allowing sufficient time to process and analyse the results. Very often this work is conducted under pressure with limited time and resources, only to result in a suboptimal flow sheet. During this phase of flow sheet test work, iterative testing will provide the information required to develop an optimal metallurgical flow sheet. The data collected will provide indicative recoveries and yields that are required for feasibility studies.Equipment specification is often included as part of process flow sheet development. This includes comparative test work between different equipment suppliers, assessment of operating conditions such as the loading to determine the number of processing units required, as well as other design information required such as particle size distributions, density and operating temperatures.While restricting the time and costs expended on test work programs may seem to meet a short term need to meet investor requirements, neglecting to develop a proper framework of the requirements that has to be met in the long-term can lead to significant long-term cost overruns. This is mainly due to a need to repeat test work, or do confirmation test work, as insufficient information was collected during the initial program.

Oct 5, 2011

By N Herault

PT Freeport Indonesia recently completed preproduction development and construction of the Big Gossan underground copper and gold mine, located in the Ertsberg mining district of Papua, Indonesia. Production has commenced with an expected ramp-up to full production of 7000 tonnes per day in 2012. The Big Gossan utilises an open stoping mine method with paste backfill.In order to deliver ore to the mill, which sits in a valley above the ore deposit, an underground production shaft and hoisting facility was designed and constructed as the key component of ore haulage. The design and construction of the Big Gossan shaft posed many challenges to the project team. Available shaft design and construction expertise were limited as this was the first shaft of its kind in Indonesia and the project was undertaken during a time of high industry demand for new shaft systems. Construction resources were also limited due to the remote location and competition with existing, producing mines for these resources and skills. The project also taxed the ability of Freeport to provide services and resources to this as well as their other projects.Completion of the Big Gossan shaft was a milestone in PT Freeport Indonesia’s plan to fully transition ore production to the underground environment in this decade.This paper deals with the various challenges faced by PT Freeport Indonesia and shaft contractor, PT Redpath Indonesia, during the construction of the Big Gossan shaft and offers suggestions to improve future shaft projects of a similar nature.

Mar 21, 2011

Large deposits present computational challenges to todayÆs commercial orebody modelling systems that are based on conventional block models. We describe a system that is specifically engineered to model and visualise large deposits. Central to the system is linear octree encoding of conventional block models and real-time conversion of three-dimensional (3D) meshes to linear octrees. We provide both methodological treatment and practical experience in implementing such a system. A commercial implementation is also presented to demonstrate the validity of the approach.

Sep 26, 2011

By H Kurth

Oyu Tolgoi copper and gold mine in the southern Mongolia holds mineral resources that make it one of the largest known copper and gold deposits in the world. The project is operating an open pit mine on the near surface of Southern Oyu deposit and developing underground block-caving mine at the Hugo Dummet North where 80 per cent of total resources exists. Oyu Tolgoi (OT) commenced open pit mining in 2011 and implemented an industry standard blasthole sampling, and ordinary kriging grade control estimation with block-out process. Since 2017, grade control improvement projects have successfully completed that have led to the implementation of current, improved grade control system. Geological model is updated by blasthole logging on Leapfrog® and used for daily grade estimations. GC estimation is proceeded solely on Vulcan® by running Lava script and integrating with a relational database. Combination of block-out procedure produces GC model which is updated in Vulcan® and as well as in the database simultaneously. Switching to the integrated database eliminated many manual processes such as importing and exporting data and enabled access to the database anytime, anywhere and from any device. Thereby, these improvements allowed to increase an efficiency, create a comprehensive reconciliation system and reduce operational risks. We are looking forward to expanding applications of integrated grade control data stored in the database. This paper outlines how the grade control system was developed at OT’s open pit mine, and how it is integrated into the short range mine planning, mine reconciliation workflow and ultimately enabled development of various automated reporting systems.

Mar 22, 2022

By J Zhang, B Wei, T Zhao, K Wang

Understanding mining-induced surface movement and fissures is critical for environmental protection and geological prevention. In this study, image recognition algorithms, satellite remote sensing and unmanned aerial vehicle photogrammetry (UAVP) were combined to identify surface movement and fissures caused by mining, and a case study was conducted in a coalmine in western China, and the following conclusions were obtained.

Sep 1, 2024

By E J. Coyle, L A. Millington

Tailings storage facilities are geotechnically complicated structures that develop heterogeneous strength profiles and varied porewater conditions. The monitoring of porewater pressures is one of the only direct measurements that can be performed to monitor the performance of a facility throughout its life and is of particular importance in upstream facilities. Foundation underdrainage, continuous and staged tailings deposition, climate inputs (rain, snow, humidity, evaporation, etc), and stratified tailings permeabilities can complicate this critical measurement that introduces uncertainty to stability analyses. These difficult conditions manifest in vibrating wire piezometer measurements as very low or negative pressure readings, both of which are within the instrument’s range of accuracy. However, the data can be difficult to interpret, and a range of interpretations are adopted from optimistic low phreatic surfaces to conservative fully saturated tailings. Where tailings are potentially liquefiable, these very low readings introduce further uncertainty regarding the pore space saturation ratio and liquefaction potential above the estimated phreatic surface. This area of uncertainty is the vadose zone, and its affect on tailings behaviour is not well understood. The two facilities analysed in this paper are upstream, raised embankments with tailings classified as clayey, sandy silt that have been found to be potentially liquefiable. The vibrating wire piezometers (VWP) at both sites show very low or negative readings when they are initially installed near the surface and then go through cycles of re-saturation and de-saturation. Eventually the readings settle as the VWPs are buried deeper within the tailings. The instrumented sections within the tailings column do not show consistent readings that would be indicative of a hydrostatic phreatic surface at either site. Rather, they are highly variable and can be interpreted as either representing a high phreatic surface within the tailings or as a ‘perched’ phreatic zone within the tailings layers. How the VWP data is interpreted has a significant impact on how the facilities are raised and operated. The design outcome for Site 1, which adopts a lower phreatic surface, results in an embankment that meets factor of safety (FoS) requirements under residual strength conditions without any buttressing. Conversely, a conservative (high) phreatic surface has been adopted for Site 2 and has resulted in the facility requiring a significant buttress to meet FoS under residual strength conditions.

Jul 1, 2021

By M Monaghan, B S. Gregory

The Geita Gold Mine is located 80 km southwest of the town of Mwanza in the north-west of Tanzania and is 100 per cent owned by AngloGold Ashanti Limited. Open pit mining commenced at Geita in 2000. In 2011, the operation produced 494 000 oz at a cash cost of US$536/oz. This is a significant improvement from 2008, when 264 000 oz were produced at a cash cost of US$742/oz.A period of relatively poor operating performance at Geita was recorded over the period from 2006 to 2009. A period known at Geita as æthe turnaroundÆ commenced in 2009, and has been remarkable to say the least. Over the last couple of years the mine has embarked on a journey, which saw various interventions and initiatives. Among the key initiatives were Project ONE (which focuses on business process framework, systems for people and safety transformation), asset integrity, fatigue management and contract mining of satellite pits.Since the commencement of the turnaround at Geita, gold production has matched market guidance. The mine has returned to positive cash flow on the basis of strong performance on cash management, improved production and increased gold price.This paper explains some of the details of the mine operationsÆ improvements, how they were implemented, their relative contributions to improved mining performance and the path ahead to best practice. Observations will be made about some improvement rules that can be applied generally in open pit mining.CITATION:Gregory, B S and Monaghan, M, 2012. The path to best practice at Geita Gold Mine, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 41-48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By K T. Mandisodza, T J. Cartledge

The principal objective of Geotechnical Engineers supporting operating mines is to provide safe working conditions and ensure that pit designs are geotechnically optimised to site conditions and pre-defined stability requirements. Pit slope designs are delivered in advance of pit excavations. Making changes to these designs is usually slow to enact and involves a layered sign-off before implementation, leading to unwanted delays in their adoption and subsequently increased production pressures. When unexpected ground conditions are encountered during the mining process, or short-term mining schedule requirements demand it, changes to these designs may not be easily feasible in certain situations. It is when these scenarios arise that Geotechnical Engineers need to be proactive and consider unconventional options to deliver safe operating conditions while satisfying short-term requirements to the mine schedule. Essentially, the geotechnical short-term strategic designs double-pronged approach supports the mine schedule while providing safe conditions and minimising geotechnical risks for people and equipment. Common short-term strategic geotechnical designs include; slope buttressing, over-steepening cut slopes to increase reserve recovery through unplanned or emergency cutbacks, and accepting risk threat and operating under unstable slopes. When implementing strategic design options, the Geotechnical Engineer must consider the broader implications for such designs. They must think of the plan’s long-term effects on the mine schedule and pit wall stability. Initiating aggressive designs to recover additional reserves to satisfy a short-term scheduling demand could result in-pit wall instability or suboptimal pit layout. Before and during the implementation phase, the Geotechnical Engineer must communicate and engage with relevant stakeholders to ensure that the plan is executed accordingly and geotechnical risks are effectively managed. Proactiveness to ground response and implementation of risk management strategies will improve safety performance and optimise mining schedules.

Jun 22, 2022

By M Nagarajan, S Esen

This paper presents three case studies from three surface coalmines. The first case study is from a coalmine where a dragline operates in 60 m wide and 1 km long strips. Typical overburden height ranges from 30 m to 50 m. The base case blast was modelled using an advanced blasting model (Distinct Motion Code – DMC) to establish the baseline using the blasting parameters in use before optimisation. DMC was used to model the alternative blasting scenarios to obtain the following key objectives:the post-blast muck pile profile was required to have an optimum height of ~28 moptimise cast percentageachieve a well-fragmented muck pile for the draglinethe muck pile profile should be appropriate for the dragline entry into the strip.Achieving these objectives would optimise the dragline performance through reducing rehandle and improving advance along the strip. DMC modelling resulted in the following outcomes:the required muck pile profile could be achievedthe cast percentage increased from 21.1 to 25.1 – a four per cent increaserehandle volumes were reduced.Establishing a good quality assurance / quality control (QA/QC) process was essential to delivering a blast that could achieve these outcomes. The blast was fired successfully and the dragline completed the strip approximately two weeks ahead of the time taken for the previous strip.The second case study is from a coalmine where D11 dozers are used to move the blasted material to the spoil. An optimum profile was required for the dozers for this low-cost mining operation. To achieve this, an electronic blasting system (uni tronicTM 600) was introduced to optimise the muck pile profiles being delivered. The new muck pile profiles showed improved cast percentage from 10.6 per cent to 17.8 per cent. The changes in the muck pile centre of mass displacement improved dozer efficiency as a result of pushing material shorter distances to its final position. Dozer productivity (bcm/h) statistically did not change but coal was being exposed at a faster rate.The third case study summarises the results from a site where dozers are used to minimise the total mining cost. Traditionally, excavators had been used on-site with conventional blast designs. After firing the first cast shot, the blasted material was found reasonably well-fragmented. Although dozing productivity hasn’t been quantified on-site, operators were providing positive feedback (easier push) due to the reasonably good muck pile profile suiting to the dozers. This site also realised significant savings with the dozing as compared to their truck/shovel operation.CITATION:Esen, S and Nagarajan, M, 2015. Muck pile shaping for draglines and dozers at surface coalmines, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 409–416 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By O Ishiyama, L Lu

Sintering is the most economic and widely used agglomeration process to prepare iron ore fines for blast furnace use. Due to the depleting reserves of traditional high-grade iron ore, there have been considerable changes in iron ore resources available throughout the world, especially in steel mills in East Asia. Corresponding to the changes in the availability of iron ore resources, the amount of impurities in iron ore has been slowly increasing. Some of these impurities have been found to have deleterious impacts on sinter quality and sintering performance. In the meantime, an increasing number of large blast furnaces with inner volumes of more than 5000 m3 have been built that require more sinter and are often more demanding in terms of the quality requirements of the ferrous materials. Finally, sinter plants are facing increasing pressure due to more stringent regulations regarding their environmental impact. This paper gives an overall review of a variety of technologies developed worldwide to tackle the changing raw material characteristics and mitigate emissions from sintering operations.CITATION:Lu, L and Ishiyama, O, 2015. Recent advances in iron ore sintering, in Proceedings Iron Ore 2015, pp 61–68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Computer software has been developed to link real-time information generated by underground mine ventilation airflow monitoring sensors into a network simulation program to undertake network simulations and allow interpretation of key system data and operational changes. Results were used in the development of a computerised monitoring and simulation system to provide immediate or real-time data on air behaviour within each branch of an underground mine ventilation network through linking of sensors to the ventilation network simulation software. The outcome of the project is an online system that can report changes in the mine ventilation system, allow causes of changes to be isolated and rectified, improve balancing of available air throughout the mine, allow improved approaches to regulator setting and dispense with much of the labour used for underground ventilation measurement. The work activities in both coal and metalliferous Australian mines have involved examination and modelling of regulators, software modification and considerable mine site testing and optimising activities. There is some discussion on approaches to control of flow through ventilation systems with increased information. New systems will be part of a total mine information management system. They will have to be cost effective and justified by gains in productivity. New systems will need to provide simulation of contaminant production such as diesels, vehicle heat, strata heat, radiation, blast fumes and other gases. More robust real-time ventilation simulation systems will be required. Personnel and vehicle identification and production tracking will be collected to provide integrated ventilation system monitoring and control. This paper examines a study to gain greater understanding of computerised real-time airflow monitoring and control within the mine production system to provide immediate simulated information in each branch of an underground ventilation network and to allow interpretation of key system data and operational changes. A case study implementing a real-time airflow monitoring and control is discussed. Approaches to control of flow through ventilation systems with increased information are discussed. The concept of a system that can be linked to or be part of a total mine information management system is developed. Such a system can form the base for mine automation that allows mines to incrementally and cost effectively implement monitoring and control to further seek gains in productivity.

Jan 1, 2005

By D Deb, R Pramanik

This paper presents a generalised methodology in smoothed particle hydrodynamics (SPH) framework to analyse dynamic failure process of rock mass having natural joint under blast-induced stress wave and expansion, and penetration of high pressure gaseous product. The necessary interactions of gas-rock are incorporated in the model which describes features of coupling between damage and plasticity in tension and compression respectively. A Drucker-Prager formulation of plasticity is used to model the behaviour of aggregate field and the Grady-Kipp damage model is employed for tensile strain. These two material behaviours are then brought together within the framework of interacting continua. The model relies on the Drucker-Prager plasticity surface to predict the dilatancy aspect of the material response and to account change of strength according to the strain rate effect. Three numerical examples are presented with rock joint and multiple blastholes.CITATION:Deb, D and Pramanik, R, 2015. Smoothed particle hydrodynamics modelling of blast-induced fracture processes in naturally jointed rock medium, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 65–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By J Heyes

Historically mining engineers haven't spent enough time planning waste dumps, but waste movement costs often outweigh ore haulage costs. There is a real incentive to plan waste dumps right the first time to minimise rehandle and final closure costs. At BHP Billiton Iron Ore there has been an increasing sophistication in waste dump design and they are becoming as important as the pit design. Closure landforms are now included in mining studies. Closure is embedded in the business planning cycle. The results from the recent life of mine study at Whaleback is a case in point where a base case of the shortest hauls with no closure constraints was compared against a closure case. A properly planned and executed waste plan revealed that no rehandle was required and haulage costs were eight per cent less if closure design implementation was carried out concurrent with mining. At cessation of mining the landforms were such that decommissioning of critical acid rock drainage dams and coverage of exposed pyrite areas could occur straight away, without the need for additional rehandle.  The paper also covers design and scheduling elements of waste design both in-pit and ex-pit, management of potentially acid forming material (PAF) and trends in PAF management and designing for final landform closure. This paper illustrates that there is value in terms of costs savings, sustainable outcomes and reputation if the mine planners are involved in the closure planning process.

Jan 1, 2009

By M Edhammer

In 2007, Atlas Copco introduced an integrated tunnel scanner/profiler. The tunnel scanner, which is integrated into the control system, is mounted on the drill rigs, and replaces the previous variants of non-integrated scanner equipment. The Atlas Copco Tunnel Profiler, which is the name of this system, is currently being used by several contractors and mines on various projects in Scandinavia, Finland and Australia. Atlas Copco Tunnel Profiler can scan a tunnel of 65 m2 in just five minutes and is integrated with the computerised control system for the drill rig. This integration means that the results of scanning are immediately available for analysis on the computer screen both in the drill rig and in Tunnel Manager; a software for tunnel and drift planning.In 2008, a method was introduced for locating the drill rig with a total station navigation (TSN) system, integrated into the control system. TSN systems are used by a number of contractors in Scandinavia and Finland, as well as elsewhere in the world. Using a TSN for navigation is in itself not new, but when this is integrated with the control system it provides the opportunity for individual drill rig operators to use this method, without the direct assistance of a surveyor. TSN gives a very precise indication of the drill rig’s position in relation to the tunnel design. An accuracy of ±1 cm compared with the ±10 cm which is normally obtained with the traditional method using tunnel laser and sight plates on the drill rig’s feeder. The closer a tunnel is blasted to its planned profile, potentially the more is saved in terms of less shotcreting, extra rock bolting and other corrective work. A better quality tunnel is the key to better overall economy and today’s technology makes it possible to achieve that goal in every type of tunnelling and mining project.In addition to total station’s ­navigation and Tunnel Profiler, the concept of ‘high precision tunnelling’ also includes:•Software tunnel planning: Tunnel Manager, Tunnel Manager Pro and Tunnel Manager Measure while drilling.•Measurement While Drilling (MWD)collects the various drilling data and the interpretation of these for the early identification of variations in the rock.•Rig Remote Access (RRA) is a support for wireless or wired communication between drill rig and planning office. The result is being able to send planning data to the drill rig and to simultaneously have the facility for logged files to be sent from the rig to the office. There is an option of an external computer logging in to the drill rig’s control system to view menu screens and settings, and remotely troubleshoot and plan appropriate action.

Mar 21, 2011

By K Sommerville, J Parkinson

"Open pit mines today have more technology and data available. The challenge is to effectively use resources to analyse and identify mine productivity improvements. AMC Consultants Pty Ltd (AMC) has completed more than 100 benchmarking studies worldwide. In the process of gathering cost and productivity data, insights have been gained on how mines are using data to drive productivity. This paper aims to share good practice on using data, what benchmarks operations should be aiming for, where mines are currently sitting, high value areas to target, and how to best prioritise improvement to meet operational goals.A key purpose of data is to assist in managing and improving operations. Key information is used to drive meetings, decisions, budget estimates and reports. Safety, equipment productivity, available stocks, grade and spatial reconciliation are examples of where data is important for management systems. The key is to keep reporting simple whilst maintaining access to source data for troubleshooting and analysis.Some operations still have paper-based reporting systems. Some operations collect data directly off machines and instruments, use cameras and have off-site control centres. The level of technology is a fit-for-purpose choice.Comparisons of productivity assumptions commonly used in feasibility studies with good practice productivity numbers sourced from AMC’s benchmarking database will be shared in this paper. A typical activity mining cost breakdown will highlight where the high value areas for productivity improvement sit.In addition to examining the productivity of each mining step it is also important to examine the impact on the mine plan. Equipment numbers, strip ratio, grade and material hardness can impact the results of bottleneck analysis. A bottleneck example case study will highlight how productivity and other factors can be used to identify and prioritise improvement opportunities.Keep it simple. Use only the critical data for meetings, decision-making, reports and plans. Knowing and communicating the key performance indicators (KPIs) you are striving for aligns the operation and prioritises improvement plans.Citation:Parkinson, J and Sommerville, K, 2016. Getting the Most Out of Technology to Drive Mine Productivity Improvements, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 84–93 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By S H. Burgmans, B Anderson

This paper aims to define the specific challenges relating to dredging fine tailings from an above ground storage facility for transferral to a mined-out pit. In addition, it compares dredging and mining perspectives on dredging of fine tailings.

Jul 1, 2021

By V Lawson

Vale’s Sudbury Clarabelle Mill processes Cu/Ni ores from a number of mines in the Sudbury basin in Ontario, Canada. Bulk sulphide flotation produces a copper-nickel concentrate with pyrrhotite as the major diluent. After successful commissioning of the Voisey’s Bay Cu/Ni Mill (VBN) in Labrador, a miniplant campaign on Clarabelle ore with the VBN flow sheet produced a significant recovery improvement over current performance. In 2001, the Mill Redesign Project moved grinding energy into rock/sulphide and pentlandite/pyrrhotite separation and in 2006 Cu/Ni separation was re-introduced to Clarabelle Mill to produce a saleable Cu concentrate. The projects were a great success. What remained was to simplify the Clarabelle flow sheet by introducing the missing components found in the VBN flow sheet. This project known as CORe has evolved through many stages including the mining boom and surviving the 2008 economic downturn and it is scheduled for completion in mid 2013. This paper outlines some of the challenges faced in this major brownfields project – organizational, technical, financial and operational.

Aug 8, 2011

Risk Management has been applied relatively slowly in the mining industry. Except for the risk concept application in financial considerations, the application of Risk Management in safety management has been far from satisfactory. When applied it was treated in a global occupational safety and health sense. Regardless of how much the mining industry has progressed over the years it is still, in many respects, `state-of-the-art' business. The safety aspects of mining are well known and yet little understood by the public. Regardless of what has been achieved so far and how much effort has been put into it, mining is regarded as an unsafe and somehow rude business. Safety records of the mining industry vary from State-to-State. Latest mining related disasters in PNG and Queensland and some other fatal accidents support this public perception. They purport a need for change in managing safety in the mining industry. The latest mining fatalities have raised the issue: What must be done to improve safety standards? Duty of care, risk management and system engineering concepts can provide some answers. Risk Management principles which have been advocated for some time provide many answers and explanations and can make safety management more constructive and workable. What has been missing so far is that this concept has neither been applied nor has been modified for its practical application and purpose on a larger scale. A risk management approach to the management of safety and health in the mining industry is addressed, herein. This approach does not attempt to provide the solution. It does, however, provide a basic understanding of what Risk and Risk Management are all about. Rational management of risk is addressed in the life cycle and system contexts. A system of continuous improvement is applied. There is always a chain of events, outcome, exposure, consequence(s), and consequence(s) value(s). It means that development of an event takes place in time and space. Dynamic circumstances have been created in or within the system. It is a decision-making process designed to provide a methodology which is directed not toward a mathematical model but toward easy use and application in dynamic working environment, by decision-makers who can be anybody from either a risk taker or a risk creator. The emphasis is placed not only on arriving at the best practical, possible and fair decision but also on structured and systematic acquisition of knowledge about the system, its hazards and associated risks, hence increasing the decision maker's ability to manage the decision-making process related to the management of risk.

Jan 1, 1995

By T Elkington, A Finch

The theory of constraints (TOC) is a business improvement method that focuses on exploiting a business’s bottleneck to deliver the highest possible profit. Early applications were mostly in the manufacturing industry; however, the theory in itself is completely generic and has now been applied widely in other industries such as services, retail, software and distribution, amongst others. The intent of the approach is attractive – it focuses on the ‘silver bullet’ rather than ‘death by a hundred projects’, and it focuses on growth rather than cost cutting. Application within the mining industry has been limited to date, although there are a few applications emerging. This paper discusses how TOC can be applied to maximise value during the project planning phase and how to maximise profits when the mine is operational. The paper uses two case studies to illustrate the approach. Case study 1 uses the approach to improve tactical mine planning, which delivers an increase in revenue of 58 per cent. The second case study is a strategic mine planning example that delivers an increase in value of 77 per cent.CITATION:Finch, A and Elkington, T, 2014. Application of the theory of constraints to strategic and tactical mine planning, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 129–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By J Boshoff, D Reid

It has been recognised worldwide that the liquefaction risk of unconstrained tailings stacks or cyclone underflow embankments requires careful consideration. The stability of a tailings deposit where the perimeter embankments are made up of hydraulic fill is often governed by post-liquefaction stability.Cyclones are frequently used around the world to classify tailings into a coarse underflow for building a tailings impoundment wall and a finer fraction that is disposed of into the basin. The shear strength of the tailings that form the outer embankment of a tailings storage facility (TSF) and the location of the phreatic surface are the two most significant factors influencing the structural integrity of the facility. The coarse underflow is placed in such a way as to contain the overflow, which is finer, has low strength and is often poorly consolidated.A cyclone field trial was undertaken at a gold mine in Western Australia to assess the feasibility of using the cyclone deposition method to optimise and increase the capacity of an existing tailings cell. The aim of the cyclone trial was to collect information to demonstrate to the client and the regulators that cyclone deposition was a feasible option for raising TSF embankments. The cyclone trial provided an opportunity to assess the cyclone under field conditions and the quantity and quality of the underflow fraction produced on-site. A variety of methods were used to assess the flow liquefaction susceptibility of the tailings underflow sample produced during the cyclone field trial.The field trial, laboratory testing and analysis will be discussed in this paper.CITATION:Boshoff, J and Reid, D, 2015. The resistance of cyclone underflow material to flow liquefaction, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 151–156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015