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By L Blackwell

Strategic mine scheduling is an industry best practice for increasing the long-term value of mining operations and supply chains. The application of optimisation technology such as mixed integer linear programming (MILP) is able to achieve a mathematically optimal result for a given scheduling model. Such a model will typically define the available source material, processing options and desired constraints for accessing and processing the material. Most strategic scheduling models, however, do not include a sufficiently detailed model of capital expenditure options related to capacity expansion.Typical strategic schedule models do not include important capital expenditure features such as capacity decay or expiration (limited lifespan of trucks), precedence relationships over time (rail construction before a new plant or non-linear expansions due to economies of scale) or mutually exclusive option sets (choices of plant size). By not including these features, a strategic mine scheduling model for a capital-sensitive operation is unable to be optimised to deliver maximum value or profitability.This paper presents several results of MILP optimisation using advanced capital expenditure modelling for mining operations and supply chains. Results of the study demonstrate that optimising capital expenditure at the same time as optimising the mining schedule allows for minimisation of capital purchasing, optimal timing for those purchases and optimal scheduling around them. Overall, this results in an increase in net present value.CITATION:Blackwell, L, 2014. Capital expenditure modelling for strategic mine scheduling, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 315–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

Study on Rational Process Flow Sheet for Beneficiating Low-Grade Cu, Mo, Bi, S, W Polymetallic Ore

Sep 13, 2010

By S Graskoski

The allocation of boggers and trucks at Telfer’s sublevel cave mine is currently assigned by manual techniques, with decision-making primarily dependant on the judgement of the operators and mine control. Field observations indicate that allocation decisions could be improved by establishing a systematic approach to dispatch. An investigation into the current state of technology determined that no currently available solution would provide a tool to make optimal decisions for the Telfer dispatch challenge.In an underground sublevel cave (SLC) environment, the destination decision is fixed and the source is variable, so open pit and block cave solutions are not relevant. Newcrest underwent a development venture with an external vendor to develop a novel production dispatch algorithm and user-friendly software program to make allocation decisions in a systematic way with consideration given for the true complexity of the operation.This new production software, nicknamed Dingo (for Dispatch ‘n’ Go), is a smart way to assist forepersons and mine control operators in their day-to-day roles of planning shifts and allocating trucks and loaders to optimal locations during shifts.CITATION:S Graskoski, 2017. Dingo – an optimisation tool to solve complex short interval control at Telfer underground mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 261–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By M Sebbag, T Taimre

Barrick Gold Corporation is proceeding with development of the Buzwagi Mine in the Lake Victoria Greenstone Belt District of Tanzania. The Buzwagi orebody occurs in the Nzega Shear zone within the Greenstone Belt and is hosted in a K-Feldspar rich granite in contact with mafic volcanic. The orebody presents 2.6 M ounces in 41 Mt of reserves, at 2.0 g/t. Over the ten year mine life, total material movement will be 261 Mt. The feasibility study was completed in 2006 and presented several technical challenges. Two principle challenges are grade control and the impact of dilution on the economic viability of the project. The principle challenges for grade control will be quality control and quality assurance in the sampling of the massive coarse grained granite, which comprises 70 per cent of the deposit. The principle challenge with dilution will be with the selective mining of the narrower mineralised zones contained within the mafic volcanics. This paper will focus on the mine planning methodology which has been applied including selective mine unit (SMU) and dilution estimation, net smelter revenue (NSR) calculation and the effects of cut-off grades to the project economics and mine schedule.

Jan 1, 2007

The demand for minerals will grow strongly to satisfy the needs of an increasing world population for materials and energy. The technical problems involved in producing these minerals will be daunting and the engineers who will have the responsibility for designing and controlling the mineral production processes must have a high level of skills. This will place a heavy responsibility on the education system. A small number of large, well equipped university departments dedicated to mineral processing and having a close working relationship with the mineral industry, and an international orientation, will be much better placed to meet the needs than a large number of small ill-equipped departments which find it difficult to remain viable in modem universities. Courses in mineral processing must be designed to meet the scientific and technological needs of industry and full use must be made of innovative educational techniques such as video conferencing in delivering the courses. The concept of a major international network of major mineral processing departments which is designed to make best use of scarce academic resources is important and should be considered by the International Committee of the IMPC.

Jan 1, 1993

Traditionally, the term ætotal systemÆ design applied to comminution conjures images of a design that addresses the usual business and operational drivers, including health, safety and environment (HSE), capital cost, operating cost, throughput and product size. In terms of the physical process, the mine to customer type studies also exemplifies an approach that satisfies a normal ætotal systemsÆ approach. As an industry there are drivers that are forcing a re-consideration of what we regard as our total system. This modification of drivers will require changes in approach and implementation to provide the best solutions. Some of the major changes that impact the drivers are shortage of skilled personnel, changing social attitudes to remote mine site work, greenhouse gas emissions (GHGE), quality of available orebodies and geographical location of new mine sites. One approach to the challenges presented by the changing business environment is to expand the system envelope around comminution to ensure that comminution, in its widest sense, helps to meet the new realities. Background to the new drivers and constraints is provided and some of the appropriate responses are examined in relation to the impact on the total system.

Jan 1, 2007

By P J. Ellen

The selection of the ore haulage system is a key decision made in the development of an underground mine. The haulage system is one of the components that define a mineÆs ability to respond to changes in mining inventory and market conditions. The complexity of this decision for Telfer Deeps was affected by the realisation during the feasibility process that the true scale of the potential underground mineralisation at Telfer was still to be quantified. This paper provides an overview of the process used in the Telfer Project Feasibility Study to select an ore haulage system for Telfer Deeps. The purpose is to highlight the value of impartially approaching tasks of this type with a robust process. The process should be able to respond to issues identified as the task progresses towards the objective of finding the best solution for an ore haulage system for the mine. For Telfer Deeps, this process resulted in the selection of a haulage system built around a shaft. The systems considered during the feasibility are discussed and the components of the haulage system constructed for Telfer Deeps are described.

Jan 1, 2005

By P Jere

Mechanically coupled rock bolts encapsulated in cementitious or polyester cartridge resin grouts have been widely adopted for various underground rock reinforcement applications. Resin grouts are considered a superior product, however, both systems have their advantages and limitations, with the relative performance, quality installation cost and cycle time as the most notable parameters. Both applications have optimal rock bolt combinations and preferred ground conditions. Cementitious grouts are favourable for use with secondary deep embedment anchors. These are installed using various equipment with a series of autonomous tasks required to complete the installation cycle. The cartridge resin system can be utilised by a bolting or face boring rock drill to complete the full support installation cycle. This reduction in equipment changeouts mid-cycle generally deems it the more practical application and popular choice for primary support. Self-drilling anchors (SDAs) and hollow bolts have been a viable alternative to traditional rock reinforcement in variable and challenging ground conditions. Using a pumpable post installation grouting system, SDAs have proven to aid the quality of installation, but due to the additional equipment and cycle steps associated with application, the cycle time is increased. In recent years, fully mechanised bolting equipment designed to utilise a combination of self-drilling anchors and a thixotropic pumpable resin installed in a single pass has entered the market. This innovation is anticipated to deliver the advantages described above, with fewer limitations, and significantly improved development and rehabilitation rates. St Barbara Mining and Byrnecut Australia, supported by Master Builders Solutions, were first to conduct extensive trials and implement this rock bolting approach in an Australian hard rock underground mine and record the actual performance.

Mar 29, 2023

By L Bertoss, D Carvalho

In the last decade, the use of advanced implicit modelling software/algorithms in mineral resource workflows has become a best practice in the mining industry. In most cases, these workflows can easily replicate the level of detail of explicitly modelled geometries, even for very complex deposits. These techniques are flexible and can produce fast results since software is responsible for generating 3D surfaces and solids based on geological and interpretation data. Nevertheless, depending on how unique and complex some deposits are, intense manual editing and input are required to honour the geological context and produce the desired outcome. The current geological modelling workflow at George Fisher Mine (GFM) is based on the semi-automatic built-in tool that generates stratigraphic sequences (stacked lithology layers) based on logging and mapping data. This tool (stratigraphic sequence from Leapfrog Geo™) works for the majority of areas in the mine but fails to capture observed mineralisation pinch-outs in operational areas and at extrapolated boundaries of the deposit. These pinch-outs have the potential to negatively impact grade forecasts if not resolved manually. Using built-in software tools only, the alternative for a more accurate model is to generate each individual layer and adding tens of thousands of manual interpretation points to honour pinch-outs (based on the amount of existing drilling in the mine and number of layers). This approach would require an estimated minimum of two to four years of a full-time employee (FTE) to be exhaustively completed. This study presents an automated approach to generate pinch-out points using a set of Python scripts that only take a few minutes to run. The newly generated points are then combined into the commercial software workflow as interpretation points, honouring observed pinch-outs. The remarkable time difference between approaches removes chance of manual errors and allows mine geologists to spend valuable time in validation and testing of scenarios, ensuring they are more representative of the deposit’s geology.

May 24, 2023

By K Gardner, R Fraval, V Singh

Using new technology to create optimised infill drill programs in underground or open pit settings, it is possible to quantify the value of a drill program. The computer designed programs are optimised to uplift the most amount of resource possible into the specified resource classification, while honouring geological, spatial, equipment and budgetary constraints. When designing ‘by hand’ balancing all these factors is a time-consuming effort with no real way to determine metrics on ‘how good’ a program will be. The optimisation considers many factors allowing geologists to apply critical thinking and domain knowledge to constrain the optimisation, letting the computer do the heavy lifting of determining hole placement. Once programs have been created, they can be integrated into a production schedule. This is a critical step in determining the correct sequencing and balancing of resource availability and seeing how a program will interoperate with other tasks in the mine. For example, if drill drives are a requirement for part of the program, will they be developed in a time frame that is useful for the goals of the program? Do we risk drilling infill holes too late to add value? Do we put production at risk by not classifying parts of the model ahead of time, thus adding to uncertainty? Using software to assist with optimising and scheduling of drilling is a useful technique to save the geologists from the mundanity of manually designing drill programs and puts metrics around the effectiveness of a program and has the potential to add quantifiable value to a program. Examples will be presented that demonstrate the effective use of drill hole optimisation, comparing manual designs with optimised designs, as well as the examples that show the effective use of scheduling.

Mar 22, 2022

By M Darvall

Magnetite ore blending has yielded signifi cant performance improvements in OneSteel’s magnetite concentrator. The magnetite concentrator beneficiates magnetite ore from the Iron Magnet Deposit and produces concentrate, which is pelletised, then fed to the OneSteel Whyalla blast furnace. Concentrator feed variability severely detracts from the concentrator’s performance, affecting both concentrate yield and grade, which impacts on all downstream processing costs.A coordinated approach has integrated mine planning, geological modelling and grade control, to minimise concentrator feed variability, through effective ore blending throughout the mining and stockpiling process.Mine planning personnel design shots that extend the full width of the orebody and hence across the stratigraphic profi le. Based on geological information contained in block-outs and in consultation with Geology, the Grade Control team allocates material to each primary stockpile, potentially from every stratigraphic domane in the orebody. This ensures primary stockpiles are designed with maximum practical homogeneity and consistency.Using only primary movement, the allocated ore is stockpiled in a layer-cake fashion. The ore is pimple dumped across the width of the stockpile footprint and on completion of a layer, it is dozed flat with an access ramp that allows dumping to commence on the next lift. The primary stockpiles are reclaimed normal to build direction and the magnetite is crushed, all in, to a concentrator feed stockpile.The ore is sampled at the crusher from a falling stream cut. These assay data, are used for benchmarking and control charting the grade and variability of concentrator feed stockpiles. The concentrator feed stockpiles have demonstrated a statistically signifi cant reduction of within pile variation, between pile variation and pile to pile variation, primarily attributable to the development of ore blending. The concentrator has seen sustained, improved performance as a direct result, which translates into lower concentrate cost per tonne and improved yield and quality.

Jul 11, 2011

By C K. McKenzie

As more and more mining operations around the world either switch to, or trial, electronic initiation systems, the breadth of knowledge and experience regarding their effective application has widened considerably.In South America, for example, there is a strong perception that in order to achieve the finest possible fragmentation, very short electronic delays must be used between successive holes within a row. Limited field studies involving measurement of fragmentation have been conducted to support that paradigm and there are few long term studies which have been strongly supported by measurements of productivity either in the pit, in the plant, or in the leaching pads.On the other hand, some well documented studies have been conducted in North America, showing not only the impact of delay timing on fragmentation but also the effect on semi-autogenous grinding (SAG) mill productivity over extended periods of in excess of 12 months. To date, those studies suggest that optimum timing is considerably longer than the times commonly used in South America.This paper explores the current knowledge of the effects of delay timing on issues ranging from size distribution to vibration impacts in pit walls, to vibration and overpressure impacts in surrounding communities. It also explores how fragmentation modelling can be adapted to reflect fragmentation trends that have been reported in various technical conferences around the world.

Nov 8, 2011

By C Hamilton

Stawell Gold Mines (SGM) is an underground mining operation located in Victoria, Australia. The mining method employed is long hole retreat stoping, utilising up and downholes and artificial concrete pillars. Stawell is currently mining the Golden Gift and Magdala orebodies.Access to the Magdala and Golden Gift deposits is via 6.0 m wide by 5.5 m high declines developed at a gradient of one in eight to one in seven from the surface to a depth of 1500 m, with a planned depth of 1650 m. From the declines, cross cutting drives are developed to intersect the orebodies. Orebodies in the Gift system are discrete lodes which are generally mined from a bottom up centre retreat to minimise geotechnical stresses.Ore development fronts are currently located between 1000 m and 1500 m below surface, with all ore being hauled to the surface using a fleet of 60 tonne underground trucks. With the use of conventional pyrotechnic long period (LP) delays, broken rock of combined ore and waste is thrown 10 m from the face and the materials hauled to the surface. The majority of the mullock from development is consumed in the underground as backfill.With the use of Orica Mining Services eDev™ Electronic Blasting System for Tunnelling, the waste is thrown up to 40 m from the face, while majority of the ore is left 5 - 10 m from the face, effectively segregating ore and waste. This enables significant recovery of gold values with minimal loss and significantly reduced dilution. By using this technique in ore drives with a 30:70 waste to ore ratio, SGM is able to haul 24 000 tonnes less mullock to the surface annually. Resue mining is applied to narrow vein headings and gives a 40 per cent grade increase at the faces as well as increasing the economic footprint of development. This will also contribute to an improved grade profile for the year from 3.98 - 4.16 g/t Au and allow extra capacity for ore haulage from stoping and for milling.This paper describes the application and the successful blast outcomes achieved using the eDev™ Electronic Blasting Systems for resue mining at SGM. Results to date, since commencement in March 2010, have been achieving significant benefits in terms of ore grade as confirmed by geologists grab sample grades. Face advance have also shown improvement with better breakage of perimeter holes giving improved face profile. These benefits are delivering increased productivity and safety performance when compared to other resue firing techniques.

Mar 21, 2011

By J Lea, P Hatherly, J L. Edwards

Coal exploration has traditionally involved the acquisition of data to enable a resource to be quantified and qualified to the extent that its economic potential can be determined. This process commonly relied on: drilling to determine the depth and thickness of coal seams, broad characterisation of the overburden and interburden, and to provide cores for coal quality analyses; basic wireline logging to cross-check the depth and thickness of coal seams and provide some indication of rock mass strength; and basic surface geophysics and remote sensing to identify major geological structures. In recent years, the adoption of the JORC Code as a basis for the reporting of resources and reserves has placed a greater emphasis on the need for detailed, reproducible data sets that not only satisfy the traditional requirements of mine planners, but also satisfy the governance requirements of corporate and financial institutions. Similarly, the development of sophisticated numerical modelling techniques for use in both open cut and underground mine design, has seen a greater demand for precise geotechnical data, in situ stress characterisation and hydrological information as routine input to the design process. These requirements, coupled with the prevailing trend toward high capital, relatively inflexible mining techniques less tolerant of geological surprises, and the need for consideration of environmental issues such as groundwater impacts and surface subsidence, requires that modern exploration programs be multifaceted, and designed to commence capturing data relevant to ædownstream issuesÆ even during the initial phases of exploration planning.

Jan 1, 2009

By B Putland, I Lovatt, D Schwann, A Cervillin

The Mount Carlton project in Queensland's North East sits on a high-sulphidation epithermal style deposit rich in gold, copper and silver. Mt Carlton is an open pit mining operation with ore processed using a primary crusher, single stage SAG mill and flotation to produce a concentrate for sale. Orway Mineral Consultants (OMC) was involved in the original design of the comminution circuit and the project was commissioned in late 2012, with first concentrate shipped in March 2013. When Evolution sought to optimise the project in 2015, OMC was invited to assist by undertaking a circuit review to identify opportunities for the optimisation. During 2016, the Mt Carlton site team implemented the optimisation strategies developed in conjunction with OMC. These included reconfiguring the SAG mill discharge arrangement, reducing the average ball diameter and allowing the mill to operate at higher speed and under more autogenous conditions. Cyclone operation was changed to constant pressure and the vortex finder size was decreased. The combined strategies improved energy efficiency and allowed higher SAG mill power utilisation. The additional power has been used to increase throughput by 2.4 per cent while achieving a 27µm reduction in product size (P80) to gain downstream recovery improvements. The reduction in grind size has been achieved with only 6.8 per cent increase in specific energy consumption because of a 6.5 per cent increase in grinding efficiency. The circuit product size is also notably more consistent due to the improvements made to the cyclones, providing benefit to the downstream flotation circuit. A significant decrease in ball consumption was also gained, saving hundreds of thousands of dollars a year in operating cost.This paper will discuss the circuit design, start up and will detail the changes made during the optimisation and why these were successful.CITATION:Putland, B, Lovatt, I, Cervillin, A and Schwann, D, 2018. Mount Carlton comminution circuit design, start-up and optimisation, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 517–528 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By J Isarua, R Mabiria

The Ok Tedi copper and gold project, located in the Western Province of Papua New Guinea, commenced operations in 1983. The open cut mine has undergone several significant transformations throughout its project life including changes of ownership, mine life extensions and varying production performance profiles. As of today, the Ok Tedi Mine is a 100 per cent PNG owned company (67 per cent State and 33 per cent Western Province and Communities) and has a life-ofmine plan extending out to about 2032.

May 5, 2022

By P Phelan

This paper presents the general background and development of raiseboring followed by case histories of circumstances where raiseboring equipment was used in a different manner to normal. Each project has been summarised for this paper as described below: Case 1: Retrieval of a 40 tonne truck from a stope at Peak Gold Mines. Case 2: Slot raising - Conventional, Uphole and Downhole Reaming at Peak Gold Mines. Case 3: Reamer recovery by Downreaming at Tower Colliery. Case 4: The importance of Mucking Raisebore Holes û Thalanga Project. Case 5: Pilot Drilling Dewatering Holes at Beaconsfield Gold Mines. Case 6: Low angle æcut offsÆ in vein at Telfer Gold Mine.

Jan 1, 1998

By Saghafi A, Kelly M, Williams R. J

A two year program of research into the feasibility of long-hole drilling for improved gas emission control has been undertaken at Appin Colliery. State of the art equipment was employed involving cableless electronic surveying and down-hole motor drilling. The project involved the drilling of 1000 m long, in-seam boreholes in the Bulli seam and boreholes of similar length drilled cross measure and then in-seam along the underlying Balgownie seam. A new concept for gas drainage was defined, employing long-holes for both predrainage and post drainage.

Jan 1, 1988

By R van Wyk

In today’s mining environment the use of heavy mechanical devices and other high-tech electronic devices like two-way radios, cellular phones and even automated mining systems, form a vital part of the daily operations of a mining site. These human-made devices and some of the naturally occurring events, like lightning and gamma radiation, can have negative effects on electronic detonators and the associated control equipment.On larger mining operations the necessity to move the point of safety for blasting further away from the blast area, introduced remote firing via radio frequencies for electronic detonator systems. Other influences on electronic detonators can be abuse or ignorance. To ensure the safety of the end-user, an electronic detonator must be resistant to some common mistakes that users can make. One of main concerns here is resistance to static discharge or incorrect wiring. Despite the daily use of electronic detonator solutions, scepticism and concern still exists amongst those who believe the system raises the risk of a premature initiation of the blast through some form of interference trigger.This paper will help users understand how electronic detonators and the associated control equipment protects itself from external influences. Focus will be on protection schemes to counter static and over-voltage discharge and methods to ensure protection of secure wireless radio links and detonator communications. With well engineered communication systems and solid static and over-voltage protection, an electronic detonator system can be more reliable and safer than other detonator systems. The following main points will be discussed:what makes a detonator an electronic detonator,static electricity and over-voltage protection,the general influence of electromagnetic energy on the detonator,the influence of lightning on detonators,the protection of radio communication’s links as used by remote firing equipment, andthe safety protection features built into remote firing equipment.

Nov 8, 2011

By Champigny N, Grimley P. H

To a bank that granted his request for a loan, the late American humorist Robert Benchley responded, `I don't trust a bank that would lend money to such a poor risk'. This quotation is unlikely to be the norm among mining companies that secure project financing. However, a poor appreciation of one of the key risks of a mining project, the reserves, often results in disastrous financial consequences. This conclusion is the subject of the discussion and analyses presented in this paper.

Jan 1, 1994