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Structurally- controlled deep leaching processes have removed vast quantities of carbonate from a substantial portion of the "silica-dolomite" enclosing the 500 copper orebody. Mine drainage subsequently allowed free access of air to the porous environment created and oxidation of sulphides commenced. During the mIne development stage the exothermic and temperature-dependent nature of these hydrolysis reactions resulted in a slow general elevation of ground temperatures. and levels of 90 - lOO°C were attained in restricted moist sulphide-rich areas.With the advent of production and extensive use of explosives, the oxidation processes were locally raised to new levels of activity. Direct interaction of explosives and sulphides in favourable conditions caused temperature rises to above 260 C. Above this point the dry oxidation of sulphides in air was initiated and rapid escalation to the vicinity of 800 C has been known to occur in isolated cases.Ground reactivity is a function of the complex interrelationship of several controlling factors and no simple index exists.Control techniques are presently aimed at prevention of temperature rises in the range 100 -260 C. Inhibition of the rapid dry oxidation processes above 260 C is difllcult and current efforts have met with only partial success.

Jan 1, 1968

By T Wambeke, J Benndorf

A risk-robust development of a heavy mineral resource requires an assessment of the geological uncertainty and spatial variability of the key factors impacting the mining and processing operation. Attributes of interest are the total heavy mineral grade, the slime content and the amount of oversized particles. The modelling of a mineral sand deposit presents two main challenges. Firstly, the exact location of the geological boundaries are obscure due to the complex interaction of the deposit formation processes. Secondly, the properties of interest exhibit a rather complex transitional behaviour across the so-called soft boundaries. Traditionally, the modelling exercise is restricted to a consecutive stochastic simulation of distinct geological facies and orebody properties. This results in different zones separated by hard boundaries, ignoring the typical transitional behaviour.This contribution presents an alternative approach which models the entire sand body as a single domain while accounting for the complex trends present. Error curves are used to infer covariance model parameters without the need of a prior removal of the trend. The principle is based on minimising the differences between empirical and theoretical errors resulting from two methods of prediction calculated for different rings of influence. The added value results from the unambiguous decomposition of the spatial variation into a deterministic trend and a stochastic residual. The trend model neither overfits nor underfits the data. The calculated residuals are thus unbiased and the uncertainty can be correctly assessed.The effort results in a characterisation of the resource uncertainty which provides a more realistic image of the spatial variability of the key properties in and across the geological domains of an existing heavy mineral sand deposit.CITATION:Wambeke, T and Benndorf, J, 2014. Optimal inference of modelling parameters to simulate complex trends across soft boundaries – a case study in heavy mineral sands, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 73–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

Taking the Presidential chair of the Australasian Institute of Mining Engineers, my first duty is to thank you for the high honour and position you have conferred on me. A position entailing the highest compliment the Institute could bestow on any of its members, and one which I feel my inability to properly fulfil, inasmuch, as you have men in your ranks of the highest scientific training residing on that great continent where the head quarters of the Institute is established, while my engagements here will not permit me leaving this colony but for a very limited period.About six years ago, during the time the mining boom was at its height, there came to this colony from England, Germany, and South Africa, several mining engineers, who in conjunction with the mining engineers here, formed an Institute which we soon found we were not able to maintain. The mining boom gradually died away, and many engineers have left the colony to find employment in other parts of the world. We made overtures to your Iqstitute to take us under your wing, which you were kind enough to do, and the outcome is that you have come over 1200 miles to hold a meeting in New Zealand. The paucity of members residing in this colony does not admit of a large attendance; but we heartily welcome you to our shores and hope you will enjoy a holiday visiting some of the principal mining centres and exchanging ideas, which not only improves our minds, and widens our field research, but also tends to lead to further economic improvements in the extraction of metals the earth contains...

Jan 1, 1903

By D Reid

Run-out analyses of tailings storage facilities are typically undertaken using methods based on rheological theory. These are reasonable techniques to model the behaviour of tailings that, through significant run-out and possibly mixing with supernatant water, are generally acting in a fluidised manner. Such modelling often follows on from two-dimensional continuum analysis models where, if failure is predicted, grid failure often occurs when deformations begin to increase. This results in a disconnect between the prediction of failure and the modelling of the potential extent of the failure.Recently, rezoning methods have been incorporated into commercially available two-dimensional soil mechanics deformation codes. Rezoning techniques enable large deformations to be modelled within a two-dimensional continuum analysis framework; however, while promising, the use of such tools is not yet widespread, and a consensus is yet to develop on how they should be applied to tailings dam run-out modelling.This paper uses FLAC rezoning techniques to model the flow behaviour of two historic tailings dam failures. The purpose of these analyses is to critically assess the performance of rezoning against some available historic failures. The required data to undertake such an analysis is outlined, along with the inherent limitations and assumptions required. Parametric analyses are outlined to address some of these issues. In general, the analyses undertaken underestimated the flow distance observed in the historic failures by varying degrees; however, in some instances, the analysis reasonably reproduced the qualitative shape of the initial failure zone. A variety of potential reasons for the discrepancy between historical observations and the models undertaken are provided.CITATION:Reid, D, 2015. The use of rezoning techniques to model historic tailings failures, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 201–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

The range of environments which control the level of ground support required vary greatly in terms of rock type, rock structure and the mining method used. At the operating mines visited during this review the level of ground support was such that incidence of rock-fall- related accidents were rare. It was also found that methods existed to support most of the conditions encountered. The main problem areas were weak rock, major geological structures, areas of heavy jointing, high development density and areas affected by high mining-induced stresses and blasting. With stope support the level of success was much lower than that achieved in development; the larger spans and more rapid changes in geometry of open stopes compared with cut and fill stoping (where cables were originally used) led to significant problems. Before a useable design method for cable support of stope walls and pillars can be obtained the precise failure mode of the walls and pillars, and the interaction of the support and the rock mass must be investigated.

Jan 1, 1982

By Firth B. A

The classification performance of a Dutch State Mines (DSM) Rapped Sieve Bend has been investigated in a series of experiments. Coal slurries of a nominal 0.5 mm size were classified in the separation range of 0.10 to 0.14 mm at pulp densities from 6 to 21 per cent by mass of solids, and flow rates of 110 to 1375 litre min-1.The results obtained showed that the partition curve and water split io oversize was dependent on the solids flow rather than slurry flow rate or pulp density. For most of the operating conditions considered an accurate classification of the fine coal was obtained. The undersize efficiency was susceptible to solids flow rate, and was less than 70 per cent for solids flow rates greater than 16.7 tonne hour-1 metre-1 width of screen.

Jan 1, 1983

By R P. Bewick

Many future and current block and panel caves extract ore from veined rock masses. These rock masses are composed of open joints forming blocks or rock with healed networks of veinlets. These two types of discontinuities pose a challenge for rock mass characterisation and classification due to difficulties in distinguishing actually open joints from healed but weak veins when diamond core drilling and excavation blasting practices disturb the rock mass. The inability of separating characteristics of open joints and healed veins has often resulted in an underestimation of the rock mass quality and as a consequence led to inappropriate assessments of rock mass response to mining (ie rock mass behaviour) and consequently deficient excavation stability assessments and ground support designs. In this paper, guidelines are provided to improve the characterisation and classification of veined rock masses. It is shown how veined rock masses can be mischaracterised resulting in often incorrect forecasting of rock mass behaviour. Following this, the classification of veined rock masses is examined. It is shown how the primary classification systems (ie Q – Barton, Lien and Lunde, 1974; rock mass rating (RMR) – Bieniawski, 1976) may not lead to reliable ratings in veined rock masses if care is not taken to differentiate between open joints and veins of varying strength. Examples are provided to illustrate how the Q and RMR systems are insensitive to veining. Finally, an example of characterising a veined rock mass for design purposes is presented.CITATION:Bewick, R P and Kaiser, P K, 2016. Characterisation and classification of veined rocks for rock mass behaviour assessment, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 825–834 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Rokot M

In a little over three years, Chevron Niugini has built up a team of relatively young, hard working men and women, mostly Papua New Guineans, who spend most of their working days out among people in the Southern Highlands and Gulf Provinces who are directly affected by the Kutubu Petroleum Development Project. These are Land and Community Relations officers, or LACROs. They take on a huge responsibility, not only representing Chevron but also being friend, advisor and negotiator, frequently dispensers of medicines, and agricultural advice and more. When things go well, others get the praise, when things go wrong, LACROs are the martyrs. Just as the geologists who locate the oil, the drillers who find it, the engineers who design the facilities, the construction gangs who build them, the landowners who claim it, and the Government who monitor it, so are the LACROs part of a team.

Jan 1, 1991

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 S Watson, L Martinez

Mine projects are complex opportunities that demand a constant assessment of uncertainty, ie risk and upside potential. This is because the value of a mine project is typically influenced by many underlying economic and physical uncertainties, such as metal/mineral prices, metal/mineral grades, costs, schedules, quantities, and environmental issues, amongst others, which are not known with much certainty at the beginning of the project. But, is uncertainty an enemy or an ally of the mine planner/analyst? To answer this question, this paper first assesses and elaborates upon the general concept of uncertainty. It then looks at the different sources of uncertainty in a mining project, such as the orebody, costs and product price uncertainties, and their effect on the final project value. Next, a general?review?of current mine evaluation techniques highlighting their limitations when dealing with uncertainty is made. Finally, an extended evaluation and risk management framework that addresses the existing uncertainty in the (greenfield/brownfield) mine evaluation process is proposed. One important characteristic of this framework is that it uses and manages uncertainty in order to generate additional value to the project; this is done through operational and managerial flexibility, which allow mine planners to minimise/maximise project risk/upside-potential giving a more realistic estimate of the projectÆs market value - this is shown in practical and simple examples occurring at different stages of a mine project, such as exploration and operation. Final conclusions are provided at the end.CITATION:Martinez, L and Watson, S, 2012. Uncertainty - An important source of (additional) value for mine projects, in Proceedings Project Evaluation 2012 , pp 131-140 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By J Heyes, R Getty, M Sanapala

Closure is an inevitable part of the life cycle of every mine. Successful closure outcomes critically depend upon early and ongoing integration of closure planning and mine planning. Early and holistic integration minimises residual risk and maximises opportunity to leave a cost-effective, positive legacy for the company, investors and future land users. Both disciplines are inherently interconnected and aim to maximise ‘value’ via trade-offs. Historically, integration of closure into mine plans has been poorly implemented across the industry. There is still a perception that closure planning only starts as the end of a mine life approaches. This inevitably leads to tension when making business decisions, with progressive closure often being deferred due to short-term drivers and incentives. To create a positive legacy after production has ceased, this tension can be managed by transparently and fully informing business decision-makers, such that the impacts of short-term decisions on long-term closure objectives are understood. BHP recently updated a business-wide standard ‘Our Requirements for Closure and Legacy Management’ designed to strengthen collaboration, education and integration of closure across the entire life cycle of the asset. Concurrently, the ‘Life of Asset’ definition was refined to include the postproduction phase, until closure objectives have been met. This paper discusses the criticality of mine planning integration with closure and how updates to Our Requirements sharpen the focus from transactional to transformational planning. These concepts are applicable to any mining operation aiming to achieve successful closure across the full asset life cycle, from exploration to post-production.

Sep 18, 2023

By D I. Cliff

The loss of 11 miners in the 7 August 1994 Moura No.2 Underground Mine Disaster was the catalyst for major change in the way safety was managed in the Australian Mining Industry. The impact was felt across all sectors not just underground coal. It was the catalyst for the overhaul of the regulatory frameworks, moving away from prescription to management systems and risk management. This had a substantial impact on the way not only the industry operated but also on how the regulator functioned. It heralded the introduction of competency-based training across all levels of the mining workforce. Since that time major improvements in safety performance have occurred. However, hiding within the statistics are some disturbing trends. This paper aims to analyse the progress made in the past 30 years and identify the current and emerging issues. Automation is bringing major production and safety benefits, but at the same time other factors such as the reduction in workforce numbers and ever-increasing production pressures are leading to high turnover rates. This in turn causes to a loss of experience and expertise. In addition, and of particular importance, is the recognition of psychosocial wellness on workforce safety. Many of these factors are not unique to the mining industry however they may be exacerbated by the scale of mining, the remoteness of the mines and family unfriendly mining rosters.

Apr 16, 2024

Mining One (M1) is often challenged with the task of evaluating deposits considering open cut and/or underground (UG) mining methods. In many near surface deposits a combination of both methods results in the optimum economic means of exploitation. As common as it is to have open pit mines eventually develop into underground mines, theory associated with determining the optimum underground/open pit interface location continues to be subject to refinement. With recent developments in underground software packages, the generation of rudimentary underground mining stopes from basic economic inputs is not only fast, it provides a practical underground mining solution. The determination of the open pit/underground interface is not new to Gemcom's Whittle 4X (Whittle). However, its solution has only ever claimed to be indicative, mainly due the rudimentary nature of how Whittle represents any potential underground mining. The efficient generation of the aforementioned underground mining solution has provided mining engineers with a unique opportunity. Underground mining can now be represented within the Whittle environment to allow the open pit/underground mining scenario to be modelled with increased accuracy. Providing Whittle with the ability to now consider mineable underground stopes combined with the consideration of time value of money (discounting), has delivered a solution with higher credibility than ever before.This paper will elaborate on the potential value gains associated with improved accuracies in the modelling of any potential underground mining in the Whittle environment. Furthermore, it will explain the importance of incorporating time value of money in the optimisation process to provide a consistent solution through to pit selection and final analysis.

Dec 6, 2010

By M Erskine, R Mills

This paper approaches tailings dam risk management from the perspective of how other high hazard industries approach the management of their catastrophic event risks, with the aim to provide recommendations from these learnings for the industry to adopt.

Jul 1, 2021

HISTORIC SIGNIFICANCE OF EXPLOSIVES TO MINERAL PRODUCTION The ancient method of breaking rock was to build a wood fire against the face, heat the rock through and then pour water on the heated ore-bearing rock to cause it to break by tension. It was too slow and costly as the forests around the mines were cleared and transport of wood became difficult. Black powder had been used for 300 years as a gun propel- lant. ('Black' after Berthold Schwartz, a German monk, Figure 1, and the inventor of the gun who was given the epitaph `Here lies Berthold the Black, the most abominable of inhumans who by his invention has brought misery to the rest of humanity'). Only at the beginning of the 17th Century, black powder was introduced for loosening rock in European mines. In 1802 Dupont started black powder manufacture on the Brandywine Creek. The ignition train of powder was enclosed in goose quills, straws, rushes, paper or wooden tubes. The time interval between igni- tion and blast was pure speculation.

Jan 1, 1988

By S Bright, M J. Masamvu, E K. Chiwandika, S Dandi, S M. Masuka

The depletion of high-grade hard and lumpy chrome ores has forced Zimbabwean ferrochrome producers to resort to low-grade friable ores that have an average of 28 per cent fines against a set limit of 12 per cent. Submerged open arc furnaces currently in use are associated with eruptions within the furnace because of the high amounts of fines, high energy consumption, as well as high SO2 and CO2 emissions. Traditionally employed agglomeration methods such as pelletising and the use of coke in the furnace have been discarded because of the pressure to lower operational costs and to achieve higher profit margins. This research aims to develop a method to incorporate lowgrade friable ore fines and unprocessed coal into production while lowering CO2 and SO2 emissions through a closed direct current (DC) arc furnace. The closed DC arc furnace could incorporate the friable ores and coal while maintaining above 90 per cent reduction rates. Preliminary findings also show that energy consumption could be reduced by up to 35 per cent by incorporating a pre-heating and pre-reduction system using the flue gases from the furnace. In the proposed circuit, the cost of production per ton of ferrochrome might be potentially lowered by an average of 30 per cent.

Jun 19, 2024

By M Armstrong, S J. Coward, A Galli

Mine management is often expected to make rapid evaluation decisions at different stages of projects based on limited and uncertain data. The challenge is exacerbated by having to distil technical complexity into a financial model that is usually designed to produce only one or two key indicators, eg net present value (NPV), internal rate of return (IRR). Mining is a complex environment with many sources of uncertainty ranging from sampling to economics. In order to optimise investment decision-making, an appropriately structured evaluation framework must be utilised. An evaluation framework should be designed to encapsulate and integrate the complexity across the evaluation cycle, ie sampling, resource estimation, mine planning and treatment, and financial and economic modelling. This complexity is diverse and ranges from sampling support, scale effects to understanding the impact of variability, uncertainty and flexibility on operational efficiency and economic viability. These complexities, combined with time and capital constraints, usually do not allow all facets of evaluation to be integrated into the model. The model must strike a balance between simplified estimation techniques and sufficient incorporation of aspects of the project that will make a material difference to the investment decision. This paper demonstrates the impact of the scale of measurement on the valuation of a mineral project. Comparisons are made between global estimation averages using a top-down approach and local estimates using a bottom-up approach. Three sampling campaigns were conducted on a virtual orebody to compare the relative NPV accuracies. Stochastic forward models were run on foreign exchange rates and are compared with the results from a fixed foreign exchange rate model.

Jan 1, 2006

The Aberfoyle Tin Mine lies on a wide sloping bench about 2,000-2,500 ft. above sea level, at Rossarden, 14 miles north of Avoca, in north-eastern Tasmania. The quartz-cassiterite veins were discovered in 1916, but mining did not begin until 1926. Trenching revealed seven small tin-bearing veins within a width of 57 ft. of Palaeozoic slates and sandstones, and it was assumed that the mineralization extended beneath the adjacent cover of Permian strata, but the presence of the main vein system (the 26 Vein System) was not suspected until the Aberfoyle Fault was discovered late in 1928.The mine has now been developed on thirteen levels, to a depth of 1,350 ft. The lower limit of economic mineralization appears to lie at about the ll-level, which is 1,060 ft. vertically below the concealed outcrop of the main veins. Production of tin and tungsten concentrates began in 1932, and to date more than 550,000 tons of ore have been mined for a recovery of 8,856 tons of tin concentrates, and 3,056 tons of wolfram concentrates, valued at approximately £6,500,000.This paper reports part of an investigation undertaken by the Mineragraphic Investigations Section of C.S.I.R.O. to study the mineral composition of the ore in relation to the apparent failure of cassiterite and wolfram mineralization to extend below the present working limits of the mine, and was first issued as Mineragrapnic Report No. 639.GENERAL GEOLOGY:The deposit consists of a series of quartz veins in a northsouth trending sheeted zone, transecting folded slates and...

Jan 1, 1957

By G Corder

Even though most major operating companies in the minerals industry have Board-level endorsed sustainability principles and objectives, design engineers typically have no mechanism that allows them to implement those objectives in their work. In addition, the existing project management systems do not readily deliver the innovative solutions needed to address key sustainability issues, such as those related to significantly reduced carbon emissions, minimal environmental impacts, and maintaining the societal ‘licence to operate’. SUSOP® (SUStainable OPerations) is an approach for the integration of sustainable development principles into the design of mineral processes, which has been developed through the Co-operative Research Centre for Sustainable Resource Processing (CSRP). Somewhat analogous to the well entrenched HAZOP (Hazard and Operability) studies, SUSOP® is a holistic, systematic and rigorous mechanism for identifying and assessing sustainability opportunities and risks at each stage of project development - from corporate planning, through design and operation, to decommissioning and rehabilitation – without compromising financial rigour. SUSOP® was developed, tested and enhanced through its application to real case studies in the minerals industry. This development path provided significant insights into the process of identifying and evaluating opportunities for improving an operation’s contribution to sustainability and its long-term business case.This paper will discuss the need for a methodical approach for integrating sustainability principles into mineral processing plant design, present the key elements of SUSOP®, and outline its development path through real case studies. In addition, the reasons why such an approach will have growing importance into the future will be raised.

Aug 8, 2011

THE power requirements of the Mount Lyell Mining and Railway Company at Queenstown, Tasmania, have, since the inception of smelting operations in June) 1896, been derived continuously from the extensive forests in the watershed of the Queen River, adjacent to the works, the fuewoodbeing of good quality, mainly composed of myrtle or beech (Fagus Ounninghami), eucalypts, and manuka (Leptospermum ericoides). The country is very rugged and mountainous, indented by numerous ravines and gullies, and intersected by, many creeks, which are subject to periodical floods, under the influence of a heavy and persistent rainfall, which averages about 110 in per annum. The areas so far exploited aggregate a total of about42 square miles, and this denuded country gives promise of ultimately becoming very valuable pastoral ground for cattle-raising. The tonnage of wood yielded per acre varies from 40 to 100 tons on stack measurement of 80 cubic feet per ton, 60 tons per acre being considered a good average yield. The gross amount...

Jan 1, 1910