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A Loss of Strength of Gold Sulfide Concentrate Before Grinding and Cyanidation Using Magnetic Impulse Treatment Gold recovery from sulfide concentrates is going with cyanidation usually. The fine grinding to 95 per cent -0.020 mm is required for refractory concentrates, in which gold encapsulated by sulfides. According energy consumption is 10 and more kW h/ton. At this paper we suggested to use magnetic-impulse treatment with small energy consumption 0.1-0.2 kW h/ton for loss of sulfide strength before grinding and cyanidation. The object of studies was the gold-pyrite flotation concentrate which was produced from ores at the Kumtor Mine, Kyrgyzstan. The concentrate composition, physic-mechanical properties and loss of strength mechanism were studied there. The tested concentrate assayed, per cent: 62.5 pyrite, 10 feldspar, 10 mica, 5 quarts, 5 carbonates, 4 haematite and another. Haematite has intimate intergrowth with pyrite ? partially with quarts. The magnetic susceptibility of haematite and less pyrite causes in these grains and mineral complex the effect of magneticstriction. As a result numbers of deformations are increased and minerals and gold are also exposed. Lateral and longitudinal strains in the minerals by magneticstriction were calculated in this work. By quantitative analysis of pyrite mono fractions were showed next micro impurities: alumina, arsenic, nickel and others elements. These micro impurities are generated a charged dislocation, cracks and micro cracks. The inter-granular links at a boundary of haematite-pyrite, pyrite-quarts, haematite-quarts have disintegrated. The dislocation is depended from mineral modulus elasticity. It was determined an indicator of mineral electro-mechanic sensitivity which characterises a conversion of electro-magnetic energy to mechanic energy. Pyrite has most dielectric constant and electro-mechanic sensitivity as haematite and quarts. The dislocations in pyrite are account for clacks and a loss of mineral strength. Size analysis of the flotation concentrate after magnetic-impulse treatment is shown the increasing the content of thin fractions by comparison no treated concentrate. Magnetic-impulse treatment has increased the effect of the next fine grinding too. The electronic microscopy has confirmed a loss of strength of gold sulfide concentrate. The gold recovery by cyanidation increased too after preliminary magnetic-impulse treatment of concentrate by laboratory tests. The magnetic-impulse concentrate studies at the Kumtor plant have showed that a recovery gold increase in the processing of cyanidation. The consumption of energy also reduced.

Sep 13, 2010

For over 50 years R W Miller & Co Pty Ltd operated old coal properties abandoned by former owners as uneconomic, some of which dated back to the last century. The companyÆs ability to survive with what were relatively poor quality coal resources required a small efficient management organisation. In 1970 R W Miller was involved in negotiations with other coal companies through coal sales contracts to develop private coal areas under the provisions of the old Coal Mining Act (1906) and these efforts led to the development of Lemington colliery. At the same time development of the Ironbark colliery holding near Newcastle commenced. In 1971, R W Miller approached the New South Wales Government for a resource replacement area to prospect for coal in the Upper Hunter Valley. Authorisation No 33 was finally granted on 30 September 1975, but the company found the area was inaccessible as most of the surface was owned by the Australian Army. Later R W Miller was granted Authorisation 66 of 2167.5 hectares at Mount Thorley near Singleton on 1 November 1976. The development of this coal mining project coincided with the second OPEC oil crisis in 1978 and a short-term boom for coal resources and the unrealistic expectations generated by the boom. This paper gives a broad outline of the development of the Mount Thorley project between 1976 to 1986 including the feasibility study and the many governmental and industrial delays that resulted in a three-year time overrun in the project development period.

Jan 1, 1998

Particle Size Measurement of TiO2 Nanoparticles in Non-Aqueous Solvent by Interactive Force Apparatus Under an Electric Field

Sep 13, 2010

Grinding and Beneficiation Characteristics of a Low-Grade Haematite Ore

Sep 13, 2010

By Liu Wenyong, Huang Yucheng, Yang Ba

High-water rapid-solidifying material, called æhigh-water materialÆ, is a new material developed by the authors over many years. The material can solidify nine times its volume of water into solid. The material is a fine kind of binder with special properties. The solidifying body of high-water material with water has quite a high early strength. The compressive strength of the material within three days can reach the same strength as conventional Portland in 28 days. One ton of the material can replace three tons of conventional Portland cement as binder. Some important achievements have been made in application of high-water material. In metal mines, based on the material, a new full-tailing cemented backfill technology has been developed. The characteristic of the new technology is that high-water material is used as binder and full tailing or alluvial sand is used as backfill aggregate. Because of the application of the new technology, major technical problems in backfill technology such as classifying of tailing, dewatering, transportation of pulp, low strength of backfill body, environmental contamination and so on, have been solved.

Jan 1, 1998

Beneficiation Studies of Dolomitic Rock Phosphate in Pursuit of Zero Waste Technology - A Case Study

Sep 13, 2010

By Burns K. L

Keyboard patterns of hundreds of minor faults with vertical displacements of 3 mm to 2 m occur within the Greta coal seam and cause serious mining problems in collieries. Many of the faults are concentrated in linear zones termed swarms. One swarm is 600 m wide and more than 800 m long and others are of comparable size.The minor faults between the swarms are normal and are relatively widely spaced and show dip-slip movements, but the faults within a swarm are clustered and show strike-slip and oblique-slip movements. Fault swarms ofthis size and frequency have not previously been described from the Sydney Basin or on a comparable scale elsewhere but appear to be a widespread phenomenon in Australian coalfields. The faults are assigned to classes onthe basis of orientation which are then assigned to sequential phases I to IV on the basis of offsetting relations between representatives of each class. Phase I faults are minor thrusts. Phase IT, Ill, and IV faults are concentratedin the swarms and show sinistral strike-slip and normal dip-slip movements. The interference of slickenlines indicates that multiple movements have occurred within a single phase; their order is (i) strike slip (ii) dip slip and (iii) oblique slip. All faults truncate and post-date both cleat and sedimentary "stone" dykes.Phase I minor thrusts trend at a high angle to the Hunter Thrust and are considered to predate the Late Permian movements on the Hunter Thrust. Phase II and III minor faults are younger and may be any age between the latePermian and Tertiary.

Jan 1, 1978

By J Jeffery, P G. Knott, F Velge, C Evans

A trigger action response plan (TARP) provides a structured response to escalating levels of risk. In mining, TARPs are typically applied to primary hazards such as inrush, strata failure or heating. Necessary for the creation and deployment of a TARP is a monitoring system capable of detecting deviations from normal conditions. The advent of real-time instruments capable of measuring diesel particulate matter now permit decision-making within shifts to address possible overexposure. Deploying a TARP for diesel exhaust emissions can lower the probability of a person’s average exposure (over a full shift) exceeding the exposure standard by detecting deviations of diesel particulate concentrations from normal conditions. This enables pre-emptive action to mitigate or protect. Another goal is to drive ambient air concentrations lower through the application of corrective actions as a result of instances where concentrations exceed ‘normal’.CITATION:Knott, P G, Evans, C, Velge, F and Jeffery, J, 2015. Trigger action response plans for diesel exhaust exposures, in Proceedings The Australian Mine Ventilation Conference, pp 129–132 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By B J. Monaghan, R J. Longbottom, D J. Pinson, S J. Chew

Recycling steel plant by-products is a critical issue for achieving both environmental and economic sustainability of integrated steel plants. A key steel plant by-product stream is dust from basic oxygen steelmaking (BOS), which can be recycled back to the BOS vessel as iron units and to aid slag formation. The major limitations for its recycling are zinc and the uncertainty in zinc speciation of the dust. This uncertainty affects the amount of dust recycled and how it interacts with the slag during processing. BOS dust in stockpiles can undergo self-sintering reactions that oxidise the iron-bearing components. As this occurs, zinc (or oxide) may combine with iron oxides to form a zinc-iron spinel solid solution phase. Knowing which zinc-bearing species are present in the BOS dust is a key aspect in understanding and developing an efficient recycling process for the dust. To overcome difficulties associated with phase identification in the BOS dust (both fresh and selfsintered), particularly the magnetite-zinc ferrite spinel solid solution using X-ray diffraction (XRD) / scanning electron microscopy (SEM) / energy dispersive spectroscopy (EDS), high end characterisation tools, transmission electron microscopy (TEM) and Mössbauer spectroscopy, were also used. Such an approach allowed improved phase identification of key zinc- and iron-bearing phases that were not previously resolvable. The zinc in fresh BOS dust was mostly present as extremely fine separate particles of zinc oxide, attached to the iron particles. These extremely fine particles were <10 nm in size. Additionally, a small amount of zinc ferrite was also identified within the sample (most likely contained within a magnetite-zinc ferrite spinel solid solution). However, the zinc in the self-sintered BOS dust, was found to be present entirely in a magnetite-zinc ferrite spinel solid solution. While this spinel phase had been previously identified by XRD, it was not clear that it contained zinc. The Mössbauer results provided definitive evidence of zinc within the spinel phase.

Jun 19, 2024

Fire suppression systems are now recognised by both NFPA 502 and PIARC as legitimate tools for both life protection and asset protection. The effectiveness of these tools for life protection demands extremely rapid and accurate incident detection coupled with rapid response. This rapid response must be integrated with other emergency systems such as emergency ventilation. The March 2007 fatal Burnley Tunnel incident in Australia graphically illustrates the potential of effectively integrated fixed suppression systems to protect people from harm and save infrastructure from damage. Despite the raft of technology available in that instance to the operator it was the human operatorÆs ability to effectively control the emergency equipment and not the equipment itself which so positively influenced the threat to life and property.

Jan 1, 2008

By A Giblett, T J. Napier-Munn

This paper presents the results of a test program evaluating the impact of sample mass on the precision of Stage 1 gravity recoverable gold (GRG) test results. Four ore types ranging from low to high GRG contents were the focus of testing. A method to predict the influence of sample mass on the confidence limits of the Stage 1 GRG test result is demonstrated. The results suggest that although small samples tend to overestimate Stage 1 GRG in samples with low gravity gold values due to higher mass pull to concentrate, such samples can give acceptable estimates of the Stage 1 GRG content with focussed sample treatment protocols.CITATION:Giblett, A and Napier-Munn, T J, 2015. Measuring the influence of sample size on the precision and accuracy of gravity gold estimation, in Proceedings MetPlant 2015, pp 367–372 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By D K. Weatherley, A N. Mainza, I Govender, L M. Tavares, M S. Powell

It is understood that rocks do not instantaneously transport along a grinding mill and are consequently not perfectly mixed, but this is conveniently overlooked in mill modelling. A lack of understanding of the transport phenomenon and the difficulty of modelling realistic transport in a complex tumbling system, contribute to this. Visual observation of segregation in AG and SAG mills and measured lag time of mill response to changes in feed provide evidence of the influence of axial transport within mills. Incorporating this lag in dynamic models should underpin dynamic simulation of milling circuits for design and for model-based control. Limitations and errors in predicting the influence of increased power via mill length versus diameter, inability to predict pebble production, and a lack of the differential in residence time across rock sizes and competences, all contribute to inadequate design prediction that can be especially acute for large Autogenous mills. Examples of dramatically under – and overloaded pebble regrind circuits and the inability to predict pebble load in AG milling discouraging the application of this energy-efficient option, point to the need for predictive modelling of breakage by competence linked to transport through and out of mills. Incorporating progress in granular flow and mixing, coupled to computational advances enable models to be based on complex breakage and transport models at high spatial resolution. This allows mechanistic models to simulate thousands of times faster than real time, opening the door to more accurate mill design, including dynamics in process simulation and to live simulation for process control – all with advanced mechanistic models. The value of grasping this opportunity is not easily refuted.

Aug 24, 2022

This brief overview of the history of Brown Coal mining in Victoria is a luncheon presentation -I do not intend to make it indigestible with extensive listings of resources or production. There is a vast pantry of collated historical records and of vari- ous predictive studies available for the enquired with a hearty digestion. A gourmet collation is provided in The Aus IMM Monograph No 11 published in 1984 entitled "Victoria&apos;s Brown Coal-A HUGE FORTUNE IN CHANCERY", currently still on offer by the Institute and available at a bargain price in the foyer at this conference. Monograph No 11 also provides a feast of excellent references on the theme of Victorian Brown Coal assembled by the several contributors. In contrast, my presentation paper is a fast-food service, extracts from the printed paper only-you have no choice-you "get what you get" and in small quantity. I hope it will tantalise your appetite -like Oliver Twist you will ask for more. -Buy the Monograph!

Jan 1, 1989

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

By T Purvis

Xstrata Copper is extending the Ernest Henry Mine with a 6 Mtpa sub-level cave (SLC) mine being constructed under the pit. The SLC mine will maintain the EHM operation until 2024 after the pit is completed in August 2011. In February 2008, the first cut of the new underground mine at EHM was fired with the start of an exploration decline. Since then Xstrata Copper has continued the development and construction of a SLC mine. During this process a number of challenges arose, some of which had not been anticipated in the planning stages, that in turn has been addressed to ensure the development continued. The challenges have been many and varied and range from setting up the portal area and commencing the exploration decline development in an active large open pit, to management of underground water. Further challenges were presented by the effects of the GFC on investment recommendations, with the scale of the mine varying from a shaft mine to a smaller scale trucking only mine in mid-2009 and back to the full shaft mine in late 2009. The effect was the parallel development of two separate mining scenarios, with the challenge of maintaining commonality for as long as possible to keep both options alive until the final board approval was obtained. In 2010 the RSPT caused further impacts. This paper will describe the current progress of mine development as well as how the various challenges have been met and some key lessons learnt from these experiences.

Mar 21, 2011

Fine Coal Evaluation by Gravity Methods

Sep 13, 2010

By A Murphy

Mining plants and infrastructure, and the decisions made by their designers, can have large impacts on their environmental and social context, commonly referred to as the site or plant footprint. They can also be the source of constructive contributions to sustainable development when designers are enabled via the information, systems and tools to incorporate sustainability in engineering processes. A facility’s footprint and the project’s contribution to sustainability – economic, environmental and social aspects – are now key considerations in regulatory approval processes and are the fundamental drivers of support, or opposition, from the project’s stakeholders.Historically, plant and infrastructure designers have not been well integrated with the environmental and social professionals who are engaged to pursue regulatory approvals. Despite this, many objectives central to technical and process engineering have in fact contributed positively to a facility’s footprint and indeed its contribution to sustainable development. Examples of these objectives include increasing process and energy efficiency, and minimising the quantities of waste requiring disposal. With the framework of sustainability, mining plant and infrastructure designers are indeed at the forefront of incorporating sustainability into resource industry projects and are central to the process of obtaining regulatory approvals and ongoing stakeholder support. The process of incorporation starts with a shared understanding of sustainability and sustainable development, and continues with project processes that facilitate information and knowledge exchange throughout the project life cycle.CITATION:Murphy, A, 2014. Incorporating sustainability into mining plant and infrastructure design, in Proceedings Life-of-Mine 2014 , pp 637–646 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

Silica reacts with cryolite at 1010&#176;C in two stages. The first stage is the formation of a sodium aluminosilicate of composition consistent with the mineral jadeite (Na20.AI20s.4Si02). The formation proceeds by atleast two different reactions. Formation of alumina or an aluminosilicate proceeds to its limiting value in the first 30 min while the formation of jadeite proceeds at a steady rate until quantitative conversion is achieved after 150 min. The net overall reaction can be expressed by the equation 6 Si02+2 Na3AlF6? (Na20.AI20s.4Si02) +2 SiF4 +4NaF.The second stage involves a slow reaction that proceeds with the evolution of a little SiF4, The net result is the formation of sodium aluminosilicates that are soluble in 30 per cent AlCIs-HCI solutions. While this could be explained by disproportionation of jadeite to form albite (Na20.Al203.6Si02) and nepheline (Na20. AI203.2Si02), it is more likely that it is due to further but limited reaction between the oxides and fiuoroaluminates.

Jan 1, 1972

Iron Concentrate Synthesised from Waste Ferrous Sulfate Produced in Titanium White Preparation

Sep 13, 2010

By R Paterson, A Christensen

The routine use of gravity gradiometry for the detection of orebodies with no outcrop is now being undertaken. The commodities and orebody styles range from banded iron ore formations to volcanogenic massive sulfide (VMS) style polymetallic deposits. This recent innovation of flying gravity gradiometry was pioneered by BHP Billiton and Lockheed Martin with the Falcon technology (Lee, 2001), and now two additional systems, also using Lockheed Martin instruments, are deployed. In South Africa, magnetic gradiometry is being developed and deployed with the same objectives in mind. In this case, a system from Institute of Photonic Technology (IPHT) is being used. The detectable wavelengths from such systems have decreased to less than 200 m in the last year, and it is expected in 2011 that wavelengths to less than 100 m, with anomaly signal strengths of less than 2 Eotvos for gravity gradiometry will be viable. The key to these advances lies in the improvements of processing software and geological modelling. In particular, methods using all the tensor components are starting to be routinely deployed to filter, level and grid the observed signal. These methods do, however, require full insight and understanding of the reference coordinate systems used by the various instrument designers and survey operators. The digital terrain models need also to be observed to an accuracy of better than 20 m cell sizes, using such techniques as Lidar. Then the terrain effects can be modelled. The topographic surface represents the largest and most proximal density contrast encountered in an airborne survey. Hence terrain effects can have significant impact on airborne gravity gradiometry data. A decorrelation of the terrain effect with the observed signal requires a method of best fitting with a regional surface density. A novel technique has been developed for this purpose. This technique uses a tensor algebra to estimate a density between 1 - 4 g/cc that explains the average observed signal. Armed with this result, the anomalous buried bodies can be revealed by subtraction.

Sep 26, 2011