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By P Moarefvand, M Osanloo

The anticipated economic life of the mine, which defines the rate of mine production, is dictated initially by the design capacity of the mill/concentrator and the production capacity of the mine relative to the grade and tonnage of ore that can be encompassed by the pit design. A small pit will result in smaller investment and cash flow; in contrast, a larger size of pit will increase capital investment and annual revenue. Since open pit mine design and long-term production sequencing are essentially based on three-dimensional block models, changes in block dimensions leads to different mine sizes, and therefore changes in the mine life. The physical characteristics of the deposit, such as reserve tonnage and ore grade, affect the expected future revenues from the mining project, and consequently they affect the life of the mine. Large blocks will increase the recoverable ore reserves and production rates and hence increase the mine life. This paper discusses the effects of the block dimension on the commercial ore reserve, grade-tonnage curve and its effect on the production rate, ultimate pit size, mining cost and consequently the mine life. The result shows that block height is the most effective parameter governing the economical life of the mine.

Sep 26, 2011

The revival of the mining industry at Captain's Flat after a long period of years of inactivity has attracted attention to the importance of the ore-deposits of that field as potential sources of supply of lead and zinc. Mindful of the necessity for taking stock of the State's mineral resources, the Department of Mines of New South Wales as part of its programme of geological investigation, carried out a survey of the oredeposits and associated country rocks during 1938 and 1940.Surface geology was mapped in detail and all available exposures were examined and logged. Unfortunately, and this condition militates against the formulation of conclusions because of insufficiem.t data, some of the older workings, notably in Keating's Section, were inaccessible and the logging of levels and stopes is by no means as complete as could be desired. However, with the progress of development and exploration, further information of geological value will come to hand for incorporation in supplementary reports. It may be expected that, under such circumstances, modification of certain statements herein expressed may be necessary but it is not anticipated that any vital alteration will be occasioned.Within the State of, New South Wales, Captain's Flat ranks second to Broken Hill as a pqtem.tial producer of lead and zinc. In addition, large quantities of iron pyrites are available for the manufacture of sulphuric acid which finds application in the superphosphate industry.The mines are now controlled by an operating company known as Lake George Mines, Ltd., incorporated in New South Wales, the parent organisation being the Lake George Mining Gorporation Ltd., registered in London.Over £600,000 has been spent by the Company in exploration, mine development, surface plant, housing and water 'conservation, while the State' Government constructed a branch railway from Bungendore at a cost of £200,000. The various activities consequent upon these development and construction programmes and the prospect of employment in the industry has led to a rapid increase in the population of the township.The State, generally, has benefited to the extent of a substantial contribution to the relief of the unemployment problem, and it is hoped that reasonable permanency will be assured to some hundreds of workers for many years.

Jan 1, 1941

By J Rowland

"Ventilation models are invaluable tools for both prediction of routine daily ventilation changesin an operating mine to circuit performance expectations at the mine in 20 yearsÆ time. Arguably ventilation offi cers are becoming increasingly reliant on maintaining an accurate ventilation model with which to do their work. This paper relates to the practical assessment of the accuracy and thus ability of a mine site ventilation model to be reliably utilised on such varied tasks. The author's experience shows that in some cases the incumbent model is found to be in a state of tune that demonstrates a mine wide detailed assessment of branch resistances is simply not required. The money spent on a detailed mine wide ventilation survey that is not required would be far bett er served purchasing much needed monitoring equipment, rather than fixing something that is possibly not even broken. The term ænot rocket scienceÆ has been incorporated into the title of this paper because it appears that many practitioners believe that circuit validation is diffi cult. As long as clear att ention to detail is paid to the actual data collection process then drawing an accuracy comparison between the circuit performance and the model performance at any particular point in time, is really very simple. This paper will show a manner in which a circuit can be analysed to determine its actual state of health by using various diagnostic tools and tips. It will help ensure that subsequent work scopes to address any highlighted model defi ciencies can be more effi ciently scoped and targeted. It will hopefully remind operational people that such self assessments can easily be done æin houseÆ if the appropriate steps are followed."

Jun 1, 2012

By F Ramos

Conventional techniques for resource estimation generally involve the laborious analysis of variograms and the specification of parameters for covariance functions. In large deposits, construction of resource models and their update require significant amount of manual work, expert knowledge and time. In this paper we take a machine learning view to the problem of resource estimation. This is a non-parametric Bayesian method, leading to automatic parameter estimation (learning). Through Bayesian learning, the parameters of the model can be obtained by optimising a quantity known as the marginal likelihood. The main advantage of this approach over conventional maximum likelihood estimators is that the objective function incorporates the OccamÆs razor principle. This allows the comparison of different statistical models û for example, models designed with different covariance functions û and naturally penalises complexity, thus avoiding overfitting. Our technique presents significant flexibility for the definition of mean and covariance functions and permits the usage of more sophisticated models.The second contribution of this work is the formulation of a data fusion mechanism that continuously updates the resource model. As mining progresses, more information becomes available. For example, the hardness of the rocks can be measured while drilling blast holes, grades of ore and contaminants are obtained from cone logging. This information is in general available at a finer spatial resolution but can be more uncertain. The data fusion mechanism can seamlessly estimate the uncertainties of the different types of information and fuse them as new measurements are acquired. This procedure can significantly improve the quality of the resource model, defining new grounds for stochastic mine planning. We demonstrate the effectiveness of our approach in estimating iron ore deposits by integrating information about different grades.

Sep 26, 2011

By D Horacek, I K. Sheppard

Ok Tedi is in a period of transition. By 2008 mill feed will consist of higher levels of high-grade but metallurgically challenging skarn ores. Additionally, the Taranaki pit will start production in 2008 along with the start-up of a new pyrite concentrator. Taranaki ores are very high in sulfur. Sulfur is captured in a pyrite concentrate prior to tailing entering the Ok Tedi River. These and other complex scheduling issues will need to be resolved over a critical three-year period. With these requirements in mind, Ok Tedi contracted AMC Consultants to develop a custom version of the Life of Business Optimisation System (LOBOS¬) to assist medium-term production scheduling at Ok Tedi. LOBOS utilities enable Ok Tedi planning engineers to:import polygon-based reserve data (Blast Masters) from MineSightÆs Interactive Planning Tools (IP Tools); graphically construct block sequencing and material flow constraints; edit constraints defining standard scheduling, processing and financial relationships; define dump and stockpile attributes; and assign capacities to production systems, plants, dumps and stockpiles. LOBOS converts Ok TediÆs production scenario into a mixed integer program (MIP) and submits the resulting model to IlogÆs Cplex MIP Solver. The Solver seeks an optimal production schedule that maximises net revenue per mill hour while meeting all constraints. This paper introduces Ok Tedi and its production requirements and relates these requirements to the facilities developed for an Ok Tedi version of LOBOS.

Jan 1, 2007

By L Tatnell, R Mackay, A Tolooiyan

The multi-reversal direct shear test (MRDS) method is commonly used to measure the residual shear strength of soils. However, when the standard direct shear (DS) apparatus is used, the MRDS method is prone to two major sources of error: load cap tilting and specimen loss. These two sources of error can cause erratic behaviour in the residual shear strength curve, making it difficult or even impossible to determine the correct residual shear strength value of the specimen being tested. This paper presents the results of new modifications to the standard DS apparatus that prevent load cap tilting and specimen loss. Consolidated drained testing was performed on highly-over consolidated cohesive soil samples from a Latrobe Valley open pit mine, with results obtained from the modified DS apparatus showing a great improvement in the residual shear strength profile compared to those obtained using the standard apparatus. Large numbers of reversals (up to 14) conducted on a single specimen in the modified DS apparatus showed no notable load cap tilting and no specimen loss occurred. The modifications are easily applied to the standard DS apparatus, and analysis and correction of the data are simple.CITATION:Tatnell, L, Tolooiyan, A and Mackay, R, 2014. Measurement of residual shear strength using a modified direct shear apparatus, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 425–434 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By H Kim, M J. Sun

In order to reduce carbon emissions from the steelmaking process and achieve carbon neutrality, global steel companies are establishing their own medium to long-term strategies and implementation plans using competitive technological advantages held by each steel company. At this point, Hyundai Steel has formulated a product-oriented carbon-neutral strategy based on innovative processing that makes use of Hyundai Steel’s own strength. Based on our experience in electric arc furnace product manufacturing and blast furnace operation in an integrated steel mill, Hyundai Steel is driving the Hy3 (Hy-cube) project, which involves a unique hybrid production system utilising hydrogen and hydrogen-based renewable energy sources. This initiative aims to achieve carbon-neutral production and eventually specialise in producing premium carbon-neutral automotive parts. The project has originality in that it involves not only designing processes using electric furnaces to produce premium steel products such as car body panels and electrical steel sheets, but also aims to reduce carbon emissions from the process, developing carbon-neutral products based on market demand. To assess the feasibility of the Hy3 project, Hyundai Steel conducted two pilot productions. The first pilot was producing a prototype of lower-arm part using electric arc furnace with three different kinds of raw materials: molten iron, HBI (hot briquetted iron), and scrap. Successful performance evaluation of auto parts with 1 GPa strength was achieved. The second pilot has been focused on tire cord steel, with the first-phase tests yielding a 33 per cent reduction in carbon footprint (CFP). Using the advantages of operating experience in electric arc furnace, Hyundai Steel is preparing for test operations producing various automotive parts using an electric arc furnace (EAF) to advance the Hy3 concept. From a medium to long-term technological development perspective, Hyundai Steel’s blueprint includes producing high-end carbon-neutral steel products using hydrogen-reduced iron as raw material.

Jun 19, 2024

By W Zirima

A detailed, mine scale non-linear numerical model of Rosebery mine has been built for the purpose of simulating life-of-mine global deformations. The model was calibrated using observations of displacement and damage, and was then used to investigate the correlation between dissipated plastic energy (DPE) and seismic event occurrence. The study is unique because the seismic data was collected over a relatively short period using a temporary portable seismic system. It is the intent to undertake significantly more work, but the analysis of limited data shows that a very good, non-linear relation between DPE and event probability is present. The observed correlation is consistent with measurements from other mines where more data was available. With more data, the strength of the correlation will allow the DPE analysis to be used during the design and sequencing phase of planning to better design the mine to minimise seismic hazards.

Jan 1, 2008

By F I. Cox, D Peeler, T Bodisco

"Diesel particulate matter (DPM), in particular, has been likened in a somewhat inflammatory manner to be the ‘next asbestos’.From the business change perspective, there are three areas holding the industry back from fully engaging with the issue:There is no real feedback loop in any operational sense to assess the impact of investment or application of controls to manage diesel emissions.DPM are getting ever smaller and more numerous, but there is no practical way of measuring them to regulate them in the field. Mass, the current basis of regulation, is becoming less and less relevant.Diesel emissions management is generally wholly viewed as a cost, yet there are significant areas of benefit available from good management.This paper discusses a feedback approach to address these three areas to move the industry forward. The six main areas of benefit from providing a feedback loop by continuously monitoring diesel emissions have been identified: Condition-based maintenance. Emissions change instantaneously if engine condition changes. Operator performance. An operator can use a lot more fuel for little incremental work output through poor technique or discipline. Vehicle utilisation. Operating hours achieved and ratios of idling to under power affect the proportion of emissions produced with no economic value. Fuel efficiency. This allows visibility into other contributing configuration and environmental factors for the vehicle. Emission rates. This allows scope to directly address the required ratio of ventilation to diesel emissions. Total carbon emissions. For National Greenhouse Emissions Reporting (NGER)-type reporting requirements, calculating the emissions individually from each vehicle rather than just reporting on fuel delivered to a site.CITATION:Cox, F I, Bodisco, T and Peeler, D, 2014. Continuous remote emissions monitoring – the lynchpin for air quality management, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 137–142 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

By B Waldon, M Valastro

A coal dust explosion is one of the most significant risks in the harsh and complex environment of an Underground Coal Mine (UCM). Reviewing literature, regulations and existing systems surrounding explosive dust management shows that there have been few advancements in managing this risk over the past 90 years. Legislation has remained relatively stagnant and minimal systems are implemented in the real world that can simplify, standardise and improve the effectiveness of UCM explosive dust management. To help bridge this gap, Corehesion, in collaboration with an UCM has designed, developed and implement an Explosive Dust Risk Mitigation System (EDRMS) utilising components of Business Intelligence (BI) that is capable of real-world use in industry. To do this the existing explosive dust management process at the associated research mine was evaluated to form high-level and detailed design requirements, focusing on digitally simplifying the procedure, not replicating it. The system was then iteratively and incrementally developed and implemented at the research mine to commence real-world use. The developed BI platform is compared with the existing process to highlight the advancements in performance transparency, efficiency and optimisation of UCM explosion mitigation. This comparison and evaluation of the real-world system implementation at the research mine demonstrate its success in automating procedure steps, providing a readily accessible source of data and enabling a proactive approach to planning and managing explosion risk mitigation. In addition to improvements just for the research mine, this EDRMS created directly address many Queensland regulatory audit findings. By finalising the total system and making the highlighted changes for standardisation, this BI system will have the adaptable capabilities for implementation across the UCM industry. As accurate data availability improves at UCMs, further work can be done to improve the systems’ optimisation techniques and integration of other risks.

Apr 16, 2024

Developing and operating mines in developing countries is never dull, but continuously challenging in terms of geology and terrain, geography and location, culture and land tenure, environmental and social issues, fiscal regimes and in some cases political risk. In addition, the rapidly changing nature of the communities with little understanding of the nature of mining at the community level requires us to continually manage issues affecting project development and mine operations with greater sensitivity. In frontier regions, people skills can become more essential than technical skills, particularly in dealing with indigenous people. Hence, managing a mining project requires a huge relationship effort.Effective communication with communities of different cultural background and proactive management of issues influencing community aspirations and desires requires not only new skills but also creativity with new concepts on how to deal with social issues under a different cultural context. The involvement of government agencies and NGOs is an important ingredient to creating understanding and collaborative approaches to common social issues. Maintaining stakeholder relationships pays in the long-run and is a useful exercise in getting information feedback from the wider community.

Jan 1, 1997

By N Burgio

Block cave mines are often thought of as rock factories where high volumes of production are mined from a fixed area suggesting little requirement for geological input and control. Yet caving operations have peculiar and specific technical requirements from prefeasibility through to post-mining reconciliation. Whilst essential elements such as resource definition, geological interpretation and sampling strategies are common to all mining methods, planning for a block cave requires a different emphasis and philosophical approach in how we deal with these issues. We will examine why a geoscientist’s input is critical towards the successful planning, design and monitoring of a caving operation.

Aug 22, 2011

By S Mitchell

Jetcrete Australia Pty Ltd, shotcrete contractor took the initiative in 2008 to discontinue the use of ‘road registerable’ concrete trucks for all underground works in Australia and internationally.The rationale for this decision was basic, safety. Historically these vehicles have been and still are involved in far too many accidents; this obvious trend needs to be addressed by engineering out the root cause of the problem which in this case is suitability for purpose.Road registerable concrete trucks have been widely used for the delivery of concrete in Australian mines for many years prior to and after the inception of wet shotcrete as ‘in cycle’ ground support in underground excavations around 1992. With this inception came a wide interest in the shotcrete process and an influx of new shotcrete contractors, all using road registerable concrete trucks to deliver the large volumes of Shotcrete required for these services and in turn largely increasing the use of these vehicles underground. The road registerable concrete trucks were difficult to control and each trip underground required the operators to maintain good management of the inherent risks. We virtually had no reasonable alternative for the industry and could only encourage the operators to drive with soft controls such as, reducing overall speed to a maximum of 15 km per hour when declining, regardless of the road conditions, coming to a complete halt prior to turning into any sharp corners, remaining in the same gear both inclining and declining.

Mar 21, 2011

By S Fityus, K Koosmen, J Simmons

The purpose of this paper is to therefore investigate the hydrogeological characteristics of tailings, coarse and mixed rejects from coal processing to enable better understanding of the potential for undrained behaviours in coal mine spoil piles. This is achieved by analysing the results from permeability and oedometer testing of tailings, coarse rejects and mixtures thereof. Focus is given to the effect that tailings content has on the behaviour of mixed rejects, the transition point between drained and undrained material behaviours, and the evolution of properties with increasing stress that would occur with increased depth of burial in a mine spoil pile. The implications of the findings are discussed with respect to spoil pile stability.

Jul 1, 2021

By S Sullivan

A recent review of resource reports lodged to statutory bodies found geological models with oversmoothed or unrealistic lithological boundaries, many of which do not represent geological appearance in the field, pit or underground drive. The underlying data is often too complex or messy to be incorporated into the resource model and is thus a simplification of reality, to the detriment of the mining operation and its shareholders. Volumes can be over- or underestimated and subsequent grade predictions can be misplaced, combining to cause over- or understatement in resource reporting to stakeholders and statutory authorities. Domain models can be improved with new modelling techniques such as machine learning. However, with poor data or improper use of machine learning techniques, the conclusions can be just as misleading as with current techniques. Machine learning rarely offers a single ‘right’ outcome, rather a range of possible outcomes from the data provided. But importantly it can take advantage of the full richness of data for more informed models. Machine learning also provides confidence in its predictions so that uncertainty in the resultant models can be quantified and passed through for risk assessment during mine planning and operation. This paper will discuss the factors accentuating complexity in deposit modelling: data diversity, structural controls, chemistry, data volumes, process workflows and external non-geological constraints. A case study illustrates the risk of reducing or ignoring complexity, which can result in an overly simplified geological model.

Mar 22, 2022

By W Assibey-Bonsu

The paper provides a brief review of the multivariate uniform conditioning and the localised multivariate uniform conditioning techniques and presents a case study based on a porphyry copper gold deposit in Peru. Two other important scenarios have been investigated and will be particularly emphasised: The recovered selective mining unit (SMU)s depend on a combination of copper and gold content, which can be expressed by means of ænet smelter returnsÆ (NSR). Two approaches are compared. Firstly, the application of a composite cut-off on NSR on the joint distribution of each grade and the application of uniform conditioning to three variables is investigated, ie for the first approach NSR is used as the main variable. The second approach considers copper as the main variable. In the case of multiple domains the procedure used to apply the technique to process mixed panels is clarified and recommendations are made.

Sep 26, 2011

Folklore suggests that oxidation is detrimental to sulfide mineral flotation, and in many instances is the reason given for values reporting in the tailing. However, while a considerable body of work examining galena oxidation is available in the literature there are very few studies that investigate the consequences of galena oxidation on its subsequent flotation in base metal sulfide ores. This work clearly demonstrates that pyrite forms a galvanic couple with galena, due to the large difference in their rest potentials, and results in accelerated oxidation of galena, particularly as the pyrite content of the ore is increased. The most obvious effect of the galvanic oxidation of galena by pyrite is the release into the system of galena oxidation products, providing an ample supply of lead ions available to activate gangue minerals, most notably of which in lead/zinc ores is sphalerite. The inadvertent activation of sphalerite by lead ions inevitably leads to the recovery of liberated sphalerite into the lead concentrate, and as a consequence a reduction in the lead concentrate grade. That is, a loss of selectivity for galena against sphalerite. If galena oxidation is excessive not only is there a considerable loss in lead concentrate grade, but also a marked decreased in lead recovery as the flotation rates of the gangue minerals increase, until they rival that of galena.

Jan 1, 2005

By M Salu

Ventilation control devices (VCD’s) and bulkheads are critical controls used for managing risk in underground coalmines. Following the Moura No. 2 mine explosion in 1994, the Queensland Mines Department required that the design of VCDs be based on live testing (such as in a mine testing explosion gallery) and more recently on numerical modelling using measured seal material properties. While the stipulated methods represent an idealistic solution, they are not practical to implement as solutions to daily challenges presented in underground coalmines.Not all VCD’s and bulkheads are placed in areas which have been mined to standard roadway dimensions. Operationally, VCD’s may be required to be placed close to intersections or require large dimensionally different areas (eg overcasts and pre-driven recovery road shutters) compared to the live testing or numerical modelling originally undertaken.This paper describes the various structural engineering methods utilised to account for the design of VCD’s where the operational requirements are non-standard. Siting and construction of VCD’s near the entry of cut throughs and geological structures requires additional design considerations. While VCDs constructed from a single material (eg sprayed mining plaster) are relatively straightforward to design, the addition of multiple openings (doors) or large pipes will complicate the structuralanalysis significantly.Temporary bulkheads used for the containment of grout such as for the construction of pre-driven recovery roads in coal mining have a significantly different risk profile to VCDs and should be designed accordingly. Recent failures and near-misses in such bulkheads have highlighted this issuefor the authors.The existence of an Australian Standard for Underground Mine VCDs and Bulkheads would go a long way to addressing many of the issues raised in this paper. Without a single, industry-accepted reference for VCD design, individual mines will have to continueto exercise their best judgements using whatever local expertise is available to them.

Oct 12, 2022

By V Gumba, S Narendranathan, C Barker, R D. H Thomas, G P. Bungard

This paper presents the positive outcomes on an EPCM project, which was undertaken in a challenging environment, whereby the design team had to generate a design with a number of stringent serviceability criteria, any deviation from which would have had significant implications to the proposed design performance. The success of the design implementation within the tight time frame hinged upon the precise installation by a skilled contractor. The overall objective was achieved as a result of close collaboration between the designer and contractor ensuring all stringent quality assurance/quality control (QA/QC) aspects were met and opportunities to optimise design without compromising on performance were identified and implemented, resulting in a cost saving of over A$13 M.CITATION:Narendranathan, S, Thomas, R D H, Bungard, G P, Gumba, V and Barker, C, 2012. The importance of collaboration between designers and contractors in implementing a design in challenging conditions, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 97-102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By Stille H

The choice between drill and blast and mechanical boring methods is often not obvious. There are several factors which may have a de- cisive influence on this choice, such as the geometry and length of the tunnel, site con- ditions and borability of the rock. Both the un- confined compression strength and the joint dis- tance have a considerable influence on the net penetration rate. Site conditions, rock quality and water conditions influence the utilization of the tunnel boring machine. The drill and blast method is normally less sensitive to devi- ations from assumed ground conditions.

Jan 1, 1987