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The ore is very 'refractory. It consists essentially of arsenical pyrites, iron pyrites, zinc blende, galena, antimony as sulphide and probably, in combination with galena, as Jamesonite, magnesium, and aluminium silicates with quartz. Some of the oxidized ore, of which there is very little, has a very interesting composition. A specimen shown to me by the ,general.manager, Mr. F. B. Stephens, consisted of hydrated arseniate of iron, orpiment, pyromorphite, lead oxide, with magnesium silicates and quartz. The ore found in the mine with a composition similar to this specimen was valued for gold contents at 60 oz. per ton. This ore is found as a small leader, which runs parallel to the main ore body, at intervals cutting through it.The ore is conveyed from the mine to the reduction works by means of a double road tram line. The mine is situated about rooo feet above the plant on a hill. The grade is so great (about I in 2) that the loaded trucks coming down are able to pullthe empty ones up, thus obviating the necessity of motive power for haulage. All that is necessary is two large grooved pulleys, fixed at the summit of the hilI, and provided with a rope-break for steadying the speed of the trucks down the hilI.

Jan 1, 1903

By Brett D

Tailings disposal and water management are one of the most important environmental issues in mining projects. The nature and the method of disposal of the tailings will determine the long term environmental impacts and must be carefully considered at the planning stage so that final abandonment can be economically achieved. If not, long term and on-going treatment and amelioration may be required to achieve environmental standards. Final abandonment requires dam safety surveillance inspection to satisfy engineering stability and hazard requirements as well as environmental issues. Environmental issues include stability, as well as rehabilitation and long term contamination potential.

Jan 1, 1991

By P M. Hancock

The West Coast contains one of the world's giant placer gold deposits with production since the 1860s totalling some six million ounces (present day value NZ$ 3.6 billion). The deposits have been worked variously by hand, ground sluicing, hydraulicking and/or elevating, blocking out, deep leading and bucketline dredging. Since the sharp gold price rise of 1979 - 1980 gold production has increased steadily (in spite of the closure of the Kaniere dredge) to some 30 000 ounces (933 kg) in 1984. Production is primarily from some 100 medium scale mining, operations treating 50 - 200 000 m3 of auriferous late Pleistocene fluvial gravels year. In spite of their economic value the deposits remain only poorly investigated and many fundamental questions relating to the origin and formation of the deposits remain unanswered. This paper attempts to describe the geology of the deposits and outline a genetic model for their formation, and then discusses some of the economic aspects and current limitations and opportunities of the growing alluvial gold mining industry of the region.

Jan 1, 1985

By R Ulusay

Rock mechanics involves characterizing the mechanical properties and behaviour of rock material and the natural discontinuities of the rock mass, while rock engineering is concerned with specific engineering circumstances, for example, how much load will the rock support and whether reinforcement is necessary. Rock engineering models developed depend considerably on the input data such as boundary conditions, the properties of rock material and rock mass. Correct evaluation of these properties frequently requires laboratory and in-situ tests, supplemented with a high degree of experience and judgment. Accordingly, since 1974, the ISRM Commission on Testing Methods has spent considerable effort in developing a succession of the ISRM Suggested Methods (SMs) for different aspects of rock mechanics and rock engineering with the contribution of a number of working groups and cooperation of some other ISRM Commissions. This paper emphasizes the need and importance of standardization of rock testing methods within the context of the ISRM SMs, gives a guideline for developing ISRM SMs and finally discusses on some implementation and contractual issues associated with rock testing and experienced in practice, and briefly introduces main future trends in rock characterization, testing and monitoring. This is an extended abstract only. CITATION:Ulusay, R, 2018. Standardisation on rock characterisation, testing and monitoring with emphasis on ISRM suggested methods, practical issues and difficulties, and future trends, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 17–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

Gentlemen, you heard the good Doctor has commissioned me to make a'summary of the proceedings to date and also to close the said proceedings. It seems that over the years the business of making a summary alternates between'Mr. Pearce and myself, also I,think that w~oever is around onthe day in question 'obtains the task and apparently I drew it this, year. It is hoped you will be patient as previous experience in this capacity'indicates that the best way to proceed is to have a brief summary on each paper and then do a summary of summa~ies. This makes the approacha little cumbersome but it is felt to be fair to each author and it brings'back to the audience some recollections of what transpired at the time and they can make their own decisions, which may not necessarily agree with those of the 'sum'marisor.

Jan 1, 1983

By D Capstick, M B. Ebell

This paper describes the test work, process design, commissioning and operation of a processing system at the Ergo gold operation that improves the extraction efficiency from gold tailings material. The improvement in recovery is derived from the separation of the gold contained within the sulfides of the tailings material and a dedicated process stream to recover that gold.The sulfides are separated by means of a flotation circuit and that resulting concentrate is subjected to a regrind of below 20 ¦m to enable a greater liberation of the gold. The ultra-fine material is then subjected to a dedicated leach circuit to recover the now exposed gold particles.The case study is an example of the challenges of introducing new technology and methodologies to a well-established operation and thereby attaining improved efficiencies and tangible business benefits.CITATION:Ebell, M B and Capstick, D, 2013. Improving extraction efficiency from Witwatersrand gold tailings using flotation and ultra-fine grinding of concentrates, in Proceedings World Gold 2013 , pp 301-306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By T Hughes

Upward pressure on all mining operations is coming from the triple bottom line. To some extent this is being offset by the rise in mineral prices, but this may or may not continue. The other serious issue facing all companies is the replacement of economic reserves as exploration levels over the past decade continued to decline in line with falling mineral prices. In order to underpin the sustainability of the mining industry it is necessary to continue to reduce cost, reduce the mine environmental footprint, whilst increasing community benefit. At the same time it is imperative that we increase the economic reserves. The highest risk is in adding new mineral discoveries as the strike rate for economic discovery decreases. Gekko Systems Pty Ltd recognises that the most simple and risk averse route to increasing economic reserves is to reduce cut-off grade in the mine, thereby bringing formerly uneconomic reserves into the economic category. We have been developing a new process flow sheet which embodies the triple bottom line and the issue of economic replacement of reserves. This paper describes this flow sheet and presents four examples where this concept is/can be applied to bring about triple bottom line benefits. Sustainability can only be assured if we are the ones in control of our environment, costs and reserves.

Jan 1, 2007

By P K. Singh

Recent advancements in understanding the detonation process are noteworthy, but they are still based on somewhat hypothetical situations. The actual variables that are essential parts of normal blasting practice have not yet been taken into account in such treatments. These include the various initiation practices employed to detonate a column of explosive, from single point initiation to multi-point initiation in blast holes, and the effect on detonation characteristics of both detonators and explosives under multi-deck and multi-hole blasting conditions. The in-the-hole velocity of detonation (VOD) of an industrial explosive is dependent on explosive’s charge diameter and blasthole diameter. The relationship between blasthole diameter and VOD provides a fundamental guideline to the rate of energy conversion and energy release within the detonation front on the interaction of explosives with the confining medium.The in-the-hole VOD of explosives was measured at four experimental sites in India for different blasthole diameters, ie 150 mm to 311 mm, but for identical explosive composition being same particle size, density, viscosity and loaded into blastholes with the same degree of confinement. The results of the studies demonstrated that there is definite relationship in in-the-hole VOD of the explosive and the diameter of the blast hole. The study also confirmed that the explosives initiated with concentrated boosters yielded higher VOD in comparison to those explosives that were initiated with multi-point priming. The measured increase in VOD of explosives for increasing diameter of holes was up to 24 per cent. The rate of change in in-the-hole VOD of explosives increases with increasing blasthole diameter. It can be further stated that the in-the-hole VOD of the explosive reaches a fairly constant value after reaching a limiting/threshold diameter of 311 mm.

Nov 8, 2011

A subsurface study of the Maria Lode and associated hydrothermal alteration of andesites within the Karangahake epithermal gold-silver deposit defined the local evolutionary sequence in the once active geothermal system.   Some implications for mining of epithermal deposits arise as a result.

Jan 1, 1984

Most orebodies have one or more boundaries which are gradational, where the decision to stop mining is based on an economic cut-off. To maximise profit, this cut-off grade must be chosen correctly. It is necessary to review cut-off grades regularly, as the optimum cut-off grade changes with time, and major changes are hard to implement in a working mine without disruption to production schedules.Whenever a cut-off grade is used, there will be errors in its application caused by errors in the estimation of block grade. These can be minimised by stringent quality control in sampling and by the use of kriging, which attempts to minimise the absolute errors in grade estimation. The kriging method used should produce the most accurate estimates of marginal grade blocks - this will not necessarily be the technique that gives the best overall prediction of head grades.

Jan 1, 1993

Flotation of Smithsonite by Using Siloxane Cationic Surfactants as Collectors

Sep 13, 2010

By Aspinall T. O, Just G. D

Computer software systems have been developed to assist in a wide range of specific mine planning and scheduling applications. In selecting appropriate systems for any mining operation it is apparent that certain features have particular advantages for each mine site. The ideal solution to this problem is to select a range of systems which best relate to sections of each mining operation. This approach raises potential data linking difficulties where output from one system is incompatible with input requirements for other systems. A study at the University of Queensland investigated the problems related to the integration of a number of mine planning and scheduling software systems. The project used data from large scale coal strip mining operations in Central Queensland. Two major computer packages used extensively in the study were the SURPAC mine planning and XPAC mine scheduling systems. Dragline and truck and shovel operations were analysed in the project. Results of the work have been directly applied at the mine site to assist current strip design by effectively automating the design procedure. This enabled sensitivity studies to determine the effects of changing dragline working levels and varying pit dimensions. Coal blending studies and procedures to optimise operations have been investigated using linear programming within a spreadsheet software application. Output from the SURPAC and XPAC programs was directly linked to the linear program for this analysis. The simulation program GPSS/PC was also used in a similar manner to assess optimisation parameters.

Jan 1, 1992

By J Abols, T Hughes

The selective recovery of gold and silver from solutions containing other metals, such as copper, is possible using AuRIX«100 resin in conjunction with the Gekko Resin Column. Selectivity is driven by controlling the solution pH, which enables activities such as loading copper, gold and silver and then selectively stripping copper before gold and silver. Alternatively gold and silver can be loaded and the copper left in solution. The selective loading of gold while reducing the silver loading has also been demonstrated, opening the possibility of producing high grade gold dorT from high grade silver pregnant leach solutions. This paper reviews the AuRIX«100 resin and Gekko Resin Column Technologies, discusses the uses of AuRIX«100 in the recovery of gold and silver and the chemistry relating to several projects for which AuRIX«100 is being tested.

Jan 1, 2005

By J Rubio

This work presents design features of an innovative in-line mixing helical (coiled) reactor for flocculation and flotation as a solid-liquid separation process for suspended particles (including liquid droplets). The device has been named flocs generator reactor (FGR), a compact system whereby the flocculation of particles is assisted by the kinetic energy transfer from the hydraulic flow through the reactor and/or by the injection of microbubbles (30 - 70 ¦m). The flow mixing presented a plug flow regime with a low dispersion degree, promoting the required hydrodynamic conditions to disperse the polymer flocculant (cationic polyacrylamide) and to generate æstrongÆ flocs of Fe(OH)3 or clays (as colloidal model systems) with aggregation using an anionic polymer, Al2(SO4)3 and poly aluminium chloride (PAC), and oil emulsions destabilisation with a high molecular weight cationic polymer. The solid-liquid separation of the flocs was then achieved either by settling or by flotation with microbubbles. This paper discusses advances in this new in-line flocculation-rapid flotation device to remove æaerated aggregatesÆ, aggregates with entrained and entrapped bubbles. Studies were carried out with different models of FGRs (varying the length:volume ratio) and process efficiency (mainly kinetics) evaluated as a function of polymer concentration and some operating parameters, namely, feed flow-rate, air:solids ratio and residence time. Results showed that the aerated flocs are readily floated with rising rates in the order of 120 mh-1, values higher than those obtained for the settling of the non-aerated flocs (18 - 24 mh-1). The FGR requires short residence times and generates dense, well structured flocs (with a mass fractal dimension, dF of about three) which withstand high shear forces. Mechanisms involved appear to include small bubble formation and their rapid occlusion (entrapment) within flocs, nucleation of bubbles at floc/water interfaces, polymer coiling as a result of æsalting outÆ effects at the aqueous/air interface and plug flow type of mixing (flocculation). Successful examples of emulsified oil and solids removal from water are shown and because in all cases high efficiencies were obtained (>90 per cent removal). Due to the high process efficiency and high loading capacity shown, the FGR appears to have good potential as an in-line flotation-separator device in applications requiring high rate solid-liquid or liquid-liquid separations.

Jan 1, 2005

By S Hapugoda, Y Tang, L Lu

The steel industry is one of the global leading CO2 emitters, accounting for approximately 7 per cent of global anthropogenic CO2 emissions. In 2022, the world produced 1878.5 Mt of crude steel. About 70.8 per cent of the world’s crude steel was produced by integrated steel mills through the blast furnace and basic oxygen furnace (BF-BOF) process, while the remainder was produced largely by mini mills using electrical arc furnaces (EAF). Compared with gas-based DRI and scrap-based EAF processes, the direct CO2 emissions from the BF-BOF process and the coal based DRI and EAF process are significantly more, as both the processes rely heavily on fossil fuels, such as coke and pulverised coal, to provide energy and reduce iron oxides. Hydrogen is very reactive and reduces iron oxides to metallic iron without generating CO2. Therefore, substitution of hydrogen for fossil fuels in these processes presents a good opportunity to significantly decarbonise the steel industry. This paper will first discuss the thermodynamic and kinetic characteristics of hydrogen and carbothermic reductions of iron oxides and then examine the behaviours of different ore types present in Australia iron ores during hydrogen reduction.

Sep 18, 2023

By R Salmon, C Jones

This paper examines the recent trend towards sustainability reporting and the application of the Global Reporting Initiative (GRI) æSustainability Reporting GuidelinesÆ. It also reviews reporting in the context of the Australian Minerals Industry Code for Environmental Management, as well as the status of public sustainability reporting globally in the minerals industry. The public reporting of environmental, health and safety, social/community and economic performance has evolved over the past two decades. Initially, separate and to some degree disparate documents were produced to report performance in each distinct area. In the early to mid 1980Æs some organisations had begun to report their environmental performance through some minor commentary in their annual financial reports or through ætokenisticÆ leaflets, often used as public relations exercises. Due to more media coverage and an elevated level of public scrutiny, organisations are no longer merely reporting their good performance, but also their bad and indifferent performance. In recent years these once separate environment, health and safety and community public reports have further evolved to become more integrated, reflecting organisations embarking on the reporting of their progress towards sustainable development. The primary factor in driving the evolution of sustainability reporting has been the increasing influence of stakeholders. Two groups of external stakeholders that have had a significant influence over public sustainability reporting in recent years have been non government organisations (NGOs) and socially responsible investment funds. Significant expenditure is involved in the preparation and publication of a sustainability report however many organisations do not appear to have examined in detail what they are really trying to achieve from their public reporting process. It is important to establish objectives for the public reporting process to achieve maximum benefits. Without a framework of public reporting objectives, the benefits of the reporting process to the organisation will not be recognised and the considerable expenditure involved will be increasingly difficult to justify. We believe that by focussing on the process rather than the document, significant benefits to the organisation can be gained. Indeed, with a proper framework of objectives and targets, the reporting process can be used as a vehicle to drive organisational change, implement management systems and improve performance. An idealised framework for a public sustainability reporting process sees the organisationÆs sustainability policies drive the entire process and determine the sustainability objectives. Specific targets are then set to realise those objectives. The targets will govern performance indicators that should be used to measure the success of target achievement and which will also define what data need to be collected. Evaluation is a key component of the reporting process to measure the success of target achievement and progress in realising objectives, as well as review the need for new targets to be set. The actual production of a public document is only one, albeit important, component of the overall reporting process. The challenges that lie ahead for sustainability reporting primarily relate to the integration of environmental, social and economic performance reporting as organisations integrate their approach to these areas. This will only happen as the culture of an organisation changes to not only accept the principles of sustainable development but to implement those principles in daily operations. The reporting process has the potential to drive that cultural change by communicating the organisationÆs sustainability objectives and setting challenging targets for their realisation. Public sustainability reporting will only achieve its maximum value when it forms an integral part of an organisationÆs sustainability management system and culture.

Jan 1, 2002

Stope back conditions in the cut-and-fill stopes at New Broken Hill Consolidated Limited often deteriorate to such an extent that, because conventional rockbolts are not able to maintain safe working conditions, square-set timber is installed. An attempt to eliminate this costly procedure has involved the use of long grouted rockbolts using high tensile prestressing wire. These bolts were developed in conjunction with the prestressing engineers of BBR (Aust.). This form of support has improved the back conditions, maintained safe working conditions, and delayed the introduction of timber in a number of stopes.Production from these stopes has been maintained at its previous level (at a rate approximately double that of a comparable timber stope).

Jan 1, 1974

By Ramani R. V

There are many important physical phenomena in mine ventilation which involve transient mass and heat transfer processes. These processes have been modeled using differential equations often solved with close form solution. Within the last two decades, many numerical schemes have been devised to solve these mass-transfer problems. Much of this effort has focused on variants of the finite element and finite difference methods. In this paper, the solution of mass transfer models in mine ventilation by finite difference technique is discussed. Specifically, the computational effort and the accuracy of the solution are presented.

Jan 1, 1988

By M Zhu, G Tranell, N Simkhada, K Jakovljevic, M Wallin

Silicon is a vital element in many products today, such as electronic components, solar devices, high-quality alloys, and many others. The growing global demand highlights the need for the development of sustainable production methods to meet this demand as an alternative to the current carbothermic reduction, submerged arc furnace (SAF) based process. An alternative to this is the aluminothermic reduction of quartz in a CaO-SiO2 slag, which not only reduces direct carbon dioxide emissions but also promotes the utilisation of secondary raw materials such as quartz fines, aluminium dross and scrap as well as secondary alumina (SA) from dross recycling. In the current study, the effects of SA and CaF2 additions to slag on the resulting metal composition and metal yield were explored. Results were compared with thermodynamic simulations using FactSage™ 8.1. Experimental results show that, in agreement with thermodynamic simulations, the silicon content of the alloy is increased, while the Ca is decreased for starting slags where CaO-SiO2 is partly replaced by CaF2. Similarly, the addition of SA to the initial slag results in an alloy with a higher silicon content.

Jun 19, 2024

Today's emphasis on the enterprise bargaining process must be seen as an opportunity for organisations to further develop occupational health and safety standards at work. In particular, this shift from a centralised industrial relations system to employer, employee bargaining, presents organisations with an excellent opportunity to develop OH & S at the `shop floor' level. This is despite real difficulties in presenting hard data on the cost benefits. Unfortunately, examination of enterprise agreements ratified by the Australian Industrial Relations Commission (AIRC), show that less than 32 per cent contain provision for occupational health and safety. Those addressing the issues of occupational health and safety have included segments such as: ò rehabilitation activities; ò a new emphasis for workplace occupational health and safety committees; ò formalising procedures related to hazard identification and control; ò the use of personal protective clothing; and ò occupational hygiene and health monitoring issues. For example, an enterprise agreement reached between CIG-Gases and their unions, included clauses which commit employees to attending ten safety meetings and two work place inspections each year, in order for them to receive any further pay rises.

Jan 1, 1995