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During the last few years the quality requirements on roads and railroads have become more accentuated due to the desire to minimise maintenance costs. This has, in turn, led to increasing requirements in the preparation of ballast materials and pavement aggregates. As the access to natural gravel in northern Europe is decreasing (due to lack of availability or by law restrictions) the use of crushed rock material is becoming more and more important. The aim of this paper is to derive and describe a universal method for the prediction of particle size distributions from compressing crusher machines such as jaw- and cone-crushers. Based on a closely defined physical model, expressions which define the size reduction process are derived. Conditions for simplifying assumptions are clearly outlined. The choice and mix of breakage functions is a central subtopic iò the analysis of the crusher machine processes. Known breakage functions are reviewed and evaluated. A new concept for determination of a true breakage operator which is related to physical properties of the crusher device and the size distribution of the feed material is introduced. Finally experimental tests are compared to numerical calculations. The method described in the paper can be a useful tool when designing crushing plants or when optimizing the output of compressing crusher Machines.

Jan 1, 1995

By M Badawi, Y Foucaud, C Veloso, J Laine, A C. Araujo

Iron is one of the most exchanged commodities worldwide. Its use for steelmaking explains the growing demand in the metal which remains mainly produced by the mining and the beneficiation of iron ores. Flotation is the most used mineral separation technique worldwide, processing several billion tonnes (Bt) of ore annually, including, in some cases, hematite and magnetite ores. Based on the physicalchemical properties of mineral surfaces, flotation aims to selectively adsorb molecules that render mineral surfaces either hydrophobic or hydrophilic, known as collectors and depressants, respectively. Hydrophobic particles are then recovered in the froth by the injection of gas bubbles travelling up in the cell and attaching the hydrophobic particles. However, despite the popularity and the good performances of flotation, mining industry faces new challenges of decreasing grades and increased mineralogical complexness in ores. Many flotation variables, especially when related to reagent adsorption, remain poorly understood and it becomes necessary to gain knowledge to enhance the existing processes. Molecular modelling techniques like the density functional theory or molecular dynamics simulations (ie Classical molecular dynamics or Ab initio Molecular Dynamics) currently represent powerful tools for different applications in material sciences, like catalysis or depollution purposes. They have recently been successfully applied in the flotation area, with an increasing number of publications dealing with this topic every year. These tools provide crucial information on bulk and surface properties as well as on the adsorption mechanisms of reagents on mineral surfaces, key step in the flotation process, and synergetic effect of collector mixtures. A better understanding of the adsorption mechanisms of flotation reagents, provided by molecular simulations, will help to finely choose flotation reagents, and even lead to the development of new reagents formulations. Overall, these tools enable the discovery of practical and industrial solutions to improve the flotation process, which will undoubtedly help the mining industry to face its future challenges.

Nov 8, 2021

By G W. Heyes, P J. Guy

Investigations were undertaken to assess the suitability of CSIROflotation methods for improving the efficiency of separation of heavyminerals in the monazite circuit at the Westralian Sands Limitedoperations at Capel, Western Australia. Flotation work was conducted on two plant samples. The first was a high-titanium product containing considerable amounts of zircon and silica as quartz and aluminosilicates, and the second was a low monazite/zircon material containing high levels of silica. A three-stage process including reverse flotation was developed totreat the first sample. In this process monazite, zircon, quartz, andaluminosilicates were selectively concentrated by flotation and screening to produce a titanium-rich product. In the first stage, an acid amine float, monazite, zircon, and some non-zircon silica were recovered and in the second stage, an alkaline amine float using a fluoride activator, more quartz and staurolite were floated. The titanium minerals were thus concentrated in the unfloated fraction. In the third stage, the titanium-rich flotation tail was screened at 250 ¦m to remove the remaining coarse aluminosilicates. In a single pass, the three-stage process yielded a TiO2 recovery of 64.0 per cent with the titanium-rich product assaying 70.3 per cent TiO2.

Jan 1, 2001

By T A. J Hopper, S Mukkisa, M L. Johns, K T. O’Neill

Technological advances the sensor design and performance for logging while drilling (LWD) instrumentation offer considerable opportunities in iron ore exploration. Here we focus on the development of a nuclear magnetic resonance (NMR) LWD tool. NMR is an advanced geotechnical logging technology capable of providing in situ measurements of the porosity, pore size and permeability of the formation of interest. The ability to provide real-time characterisation of iron-ore systems is beneficial to both drilling operations as well as real-time formation evaluation. The development of an NMR LWD tool for mineral exploration drilling has previously not been achieved due to the significant technical and environmental challenges associated with the design and operation of such a tool. The tool outlined in this work is designed to work in reverse-circulation (RC) drilling systems. As such, the tool needs to be compatible with the RC drill-string, as well as being highly robust to survive the shocks and vibrations experienced during RC drilling operations. The magnetic physics of the probe must be capable of measuring at the appropriate depth into formation whilst being subject to the array of motions experienced during drilling operations. Furthermore, conducting accurate NMR measurements in an iron ore formation is challenging and the measurement methodology must be tailored to characterise the magnetic environment. The tool also requires high-powered electronics capable of operating the necessary pulse sequences for excitation and acquisition. The resultant tool design must therefore optimise the inherent trade-offs which exist between the physical components (ie mechanical structure, magnetic components and electronic hardware) in order to operate appropriately whilst not hindering RC drilling operations. Current experimental analysis of the prototype indicates that the current probe design exhibits the required measurement specifications and is nearing field testing. Future work will look towards commercialisation of the instrument.

Nov 8, 2021

By T Casten

Freeport IndonesiaÆs DOZ (Deep Ore Zone) mine is scheduled to commence production in the second half of 2000. The DOZ will produce 25 000 tpd using mechanised block cave mining methods and will have a number of major improvements when compared to previous block cave mines in the district. The DOZ will have an independent and improved ventilation system, a flexible and efficient truck haulage system, and a more reliable crushing and conveying system than in previous underground mines in the district. This paper will describe the mine plan, haulage, and ventilation systems, and compare them to those used in other operations in the district.

Jan 1, 2000

A good blending system is one that ensures that a plant can cope with the amount of grade variation that it will encounter. Prediction of amounts of variation that will be encountered on time or tonnage scales that are important should be regarded as an essential part of the planning of mines and plants. In some cases, the natural amount of grade variation when ore is mined and handled in the cheapest way will be acceptable. In other cases, it is necessary to understand the effects that various ore-handling processes have on amounts of grade variation at various scales and to design a blending system with considerable care. Blending tends to matter more when plants are sensitive to many aspects of grade. It can be very difficult to find the best compromise between capital cost and the amount of grade variation. In these cases it is important that ore blending options be considered carefully as part of the planning of mines and plants. Failure to make plans that consider likely amounts of variation can be very expensive.

Mar 1, 2010

Wet mining of auriferous gravels at L & MÆs Waikaka operation in Southland creates spoil dumps derived from stripping of a clay rich overburden, tailings from past dredging and the processing of auriferous sands and gravels. Over recent times, spoil dumps have slumped on six occasions, threatening the viability of the wet mining operation. Close examination of slump morphology, coupled with the sequence of material placement and rate of dumping suggested a mechanism associated with undrained failure of a 2 m layer of silt and sand tails forming the base of dumps.Commencing with some information on the geotechnical properties of source overburden, back analysis of failure morphology and sequence and development of undrained loading conditions from first principals, the most likely failure mechanism and factors controlling failure were defined. Based on analysis results, a scheme to stabilise the lowwall dumps was developed and implemented, augmented by continuous monitoring of pore pressures in the basal wet tails, and laboratory testing for confirmation of computed material properties.Lowwall spoil stability has improved since implementation involving changes to the method of spoil loading, and modification of wet tails composition to improve permeability and drainage of the basal wet tails under load. The method and approach to prediction and verification of failure mechanism provide a sound basis for continued mining of deeper auriferous gravels.

Jan 1, 2002

By D J. Williams, S Islam

Worldwide production of black coal amounts to about 8 billion tonnes. Perhaps 20% of this annual production is washed to improve its quality, generating perhaps 250 million tonnes of coal tailings annually, generally in the form of a slurry. The coal tailings slurry is typically thickened to about 25% solids by mass prior to disposal to a tailings storage facility (TSF), and hence comprise mostly water (about 85% by volume), plus sand, silt and clay-sized mineral particles and carbonaceous material. While the tailings settle and consolidate on deposition in the storage facility, their high moisture content makes them prone to run-out should the tailings dam fail, and makes rehabilitation of the tailings difficult. Hence, it is important to understand the consolidation and shear strength of coal tailings. Laboratory consolidation testing of coal tailings from a slurry to a soil-like state has been carried out in a purpose-built, large-scale, slurry consolidometer, instrumented with load cells and pore water pressure (PWP) transducers. Laboratory vane shear testing of coal tailings produced at different gravimetric moisture contents has also been carried out. The test results have allowed a regression model to be developed relating the peak vane shear strength of the coal tailings to their gravimetric moisture content.CITATION:Islam, S and Williams, D J, 2018. Consolidation and shear strength of coal tailings slurries, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 62–71 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

This paper will discuss Fordertechnik dawatering screens and their application in process industries. Fordertechnik screens were designed for the dewatering of deslimed, wet fines materials encountered in the mineral beneficiation, sand and coal processing industries. However, these screens have also been used in such industries as municipal waste treatment, paper pulp, chemicals and the food industries. Fordertechnik screens are of simple design and, as a result, offer low capital and maintenance costs. The design is based on the use of twin counter-rotating vibratory motors which provide high frequency, low amplitude linear movement of the screen deck which is essential for high production requirements. Fordertechnik dewatering screens are engineered and manufactured in Australia by Mitchell Cotts Engineering under licence to Fordertechnik GmbH of Mulheim, West Germany

Jan 1, 1984

By A Bagis

Road tunnels are an accepted and effective transportation solution in urban areas to mitigate increasing traffic congestion and facilitate improved urban connectivity in a cost effective manner while meeting societal goals to reduce the impact of construction. In designing a tunnel system, there is a requirement to achieve an acceptable level of in-tunnel air quality, as well as meeting ambient air quality goals. In Australia, there is also a requirement for zero portal emissions which means that all pollutants must be emitted to the atmosphere via a ventilation stack.Traditionally, effective pollutant dispersion has been achieved by constructing tall ventilation stacks which disperse pollutants into the atmosphere at a high level. The dominant variable parameters in the effectiveness of the dispersion under the ventilation engineers control are the efflux velocity, the height of the ventilation outlet and the concentration of pollutants at the point of discharge. During off-peak operations the required ventilation exhaust rate can be reduced due to the decrease in traffic. This can lead to a drop in the efflux velocity from the stack and therefore the effectiveness of the dispersion. This potentially drives the need for a higher outlet, or an increased exhaust rate to achieve a higher efflux velocity with consequent effects on energy consumption.The paper proposes a method of varying the cross-sectional area of the ventilation stack with the use of motorised control dampers, thereby maintaining a sufficiently high efflux velocity throughout the 24 hour period independent of traffic conditions. This allows the use of a potentially shorter ventilation stack.

Mar 8, 2011

By N Murphy and, S Santomartino, M Cramer

Acid rock drainage (ARD) can have detrimental effects on mining infrastructure, water reuse options and environmental discharge. As a result, some form of short- or long-term treatment is required at many mine sites. Successful treatment depends on a number of factors including the selection of an appropriate treatment technology and its correct implementation. A variety of passive and active technologies are available for dealing with ARD. Passive treatment solutions do not require continuous chemical inputs but take advantage of naturally occurring chemical and biological processes. They are often low cost, site specific approaches and are predominantly used in post-closure situations. Passive systems are well suited to drainage with low acid loads and low soluble aluminium concentrations, and are more effective with highly reduced (ie low oxygen) water. While they are often regarded as permanent fixes, most require some form of ongoing maintenance and all have an engineered life expectancy (ie finite carbonate and organic matter budgets). Passive treatments include, oxic limestone drains, anoxic limestone drains, limestone diversion wells, various reducing and alkalinity producing systems, pyrolusite limestone beds, aerobic and anaerobic wetlands, permeable reactive barriers (organic ¦ carbonate and zero valent iron), slag leach beds, and gas redox and displacement systems (GaRDS). Active treatment solutions require a continuous or semi-continuous activity (eg reagent dosing) to correct water quality issues. They can be engineered to treat virtually any type of drainage or site specific ARD issue, and have no set acid load or redox limitations. Tasks handled by active treatment systems are almost invariably larger and more costly than for passive systems. Active treatment approaches include; pH control, adsorption/absorption, ion-exchange, electrochemical concentration, biological mediation/redox control, flocculation/filtration and crystallisation. A range of generally available and proprietary technologies has been developed around these approaches. Active treatment involving pH correction with alkaline amendments is the most common and cost-effective form of ARD treatment. A variety of fixed plant and portable treatment systems are available. Calcium-based reagents, including quicklime (CaO), hydrated lime (Ca(OH)2) and limestone (CaCO3) remain the reagents of choice for the majority of active ARD treatment worldwide. This is principally due to their widespread availability, non-proprietary nature, and variety of proven dispensing technologies and cost-effectiveness. Limestone, in particular, is a very low cost reagent. However, due to æefficiency of useÆ problems with limestone in passive treatment systems, combined with its very low cost, there has been a recent emphasis on developing active treatment systems that use limestone efficiently. As the requirement for treatment increases, there is a growing emphasis on treatment sludge management and sludge stability. The final choice of a suitable treatment technology is dependent upon water chemistry (eg pH, type of metal contamination, acidity), flow rates, acid load, local natural resources (neutralising materials, topography), climate, site logistics, environmental risk and economics. The benefits and limitations of both passive and active treatment technologies are summarised.

Jan 1, 2003

The Khanong supergene-enriched copper resource, (~23 Mt at 3.0 per cent Cu), is one of several resources recently discovered in the intrusive-centred, sediment-hosted Au-Cu Sepon mineral field located in southern Lao PDR. The unusual style of hypogene mineralisation and unique set of conditions have resulted in the development and preservation of a supergene-enriched profile in this subtropical climate. Hypogene sulphide-rich mineralisation replaced calcareous cataclastite (fault rock) developed in the flat-lying, extensional, Khanong Fault. Spatially, the hypogene mineralisation was immediately out board of the skarn û hornfels Cu-Bi front and in board of sediment hosted Au-(As-Sb) mineralisation in a zoned intrusive-centred hydrothermal system. In situ supergene enrichment of the sulphide protore has resulted in a high-grade chalcocite-clay zone (~10.3 Mt at 4.6 per cent Cu) overlain by leached limonite-clay. A very high-grade in situ to exotic limonite-clay Cu-oxide-mineral zone is locally developed above impermeable dolomite at the base of chalcocite-clay zone. Exotic Cu-Mn-wad mineralisation developed for up to 1 km down the hydraulic gradient from the chalcocite-clay zone. Unique supergene enrichment conditions have resulted in the high-grade Khanong Cu resource in a subtropical weathering environment. The base of the currently active supergene profile coincides with the base of a flat-lying, pyrite-rich fault rock, dipping parallel to the hill slope, maximising Cu enrichment. Meteoric water has been channelled along subvertical faults and narrow horizontal subsurface zones. Low permeability of the fault host rock and footwall rocks has controlled the low volume and slow movement of groundwater required for supergene enrichment. Erosion has been slowed by the resistive ironstone and limonite-clay layer at surface, which assists in preserving the gentle slope over the chalcocite-clay zone.

Jan 1, 1999

By B T. Qin, C Zhu, Y W. Jia, Y Lu, F L. Li, Q L. Shi

Air leakage through rock fractures in coal mining is a major cause of coal spontaneous combustion. In order to overcome the deficiency of the existing fire control technology and prevent coal spontaneous combustion by isolating coal from oxygen, the article proposes a novel technology of inorganic solidified foam (ISF) with high expansion to fill fractures effectively. ISF consists of fly ash, cement, setting accelerator, redispersible polymer powder, water and aqueous foam. For preparing homogeneous and stable ISF, a preparation system with a pore type foam generator, a mixer device installed with a hollow shaft and helical blades, air compressor, slush pump and monitoring instruments was developed, and the working principles of key devices were elucidated. Based on a series of experiments on the different ratios of each component material and technological parameters of the preparation system, ISF with a foam expansion ratio of 8~10 and dry density of 250–400 kg/m3 was prepared. The relationship between elastic compressive strength, modulus of elasticity and density was summarised. Based on the injection experiment for fracture of loose coal pile with high temperature, the characteristics of sealing air leakage, compressive strength, thermal insulation, flow and cooling of ISF in the fresh state were investigated, indicating that ISF can effectively cut off the air leakage and cover the coal sample to reduce the temperature in the earlier stage, and ISF can remain stable and not crack. The ISF was applied to Luwa coalmine to seal small coal pillar pressure fractures and loose coal fractures in goaf. After press-casting the ISF in Luwa coalmine, the pressure-difference of inner-outer increased, meaning the effect of external conditions on the pressure-difference decreased, showing that it could plug the air leakage effectively.CITATION:Qin, B T, Shi, Q L, Lu, Y, Zhu, C, Li, F L and Jia, Y W, 2015. The novel technology of inorganic solidified foam with high expansion for preventing coal spontaneous combustion, in Proceedings The Australian Mine Ventilation Conference, pp 121–126 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

Mining and metals projects have tended to increase in both scope and cost to a point where many projects are Droperly designated as superprojects. Specialist engineer- constructors have developed organisations and systems to provide project management services during the design and construct phase of large projects. However, the engineer-constructor is also required to provide a wide spectrum of services during the evolution of large projects prior to the construction phase. Some common phases of pre-construction evolution are identified together with the associated types of specialised services which may be required. A project management team approach is described which has been developed for the design and construct phase. It is suggested that a modified matrix organisation could be adapted to the provision of special- ised services as well as to project management for ore-construction phases of the project.

Jan 1, 1980

The following is a discussion of a new approach to safety when developing or applying a new mining technology. In the form of an engineering process, the following approach had its inception in the military and aviation industries and is also very strongly evident in the chemical industry.The process has been developed and applied in the mining industry by the author. It is called 'Incremental Development and Management of New Technology'.The process is a composite of carefully selected System Safety Management, System Engineering and Financial techniques and methods. It consists of modules which can be modified to suit the requirements of a specific project. Modules provide an organised framework of activities to facilitate a gradual acquisition of pertinent knowledge and information and to enable progressive evaluation or verification of produced outcomes against specified requirements.

Jan 1, 1992

By M Spiteri, S Woth, J Caratti, K Henley

Blasting is an essentially violent process aimed to disrupt and loosen rock for productive excavation and downstream processing. Dilution of the orebody to some extent is the inevitable result, particularly in narrow vein gold mines. A small change in gold recovery is usually a strong lever on revenue generation. As a result blast designs are carefully engineered to both minimise and control the direction of rock movement. Traditionally blast designs in gold mines have used the minimum powder factor that will still permit rock excavation. This now conflicts with the recent industry trend to optimise the total process flowsheet from the mine to the mill. Numerous mines have achieved success in reducing total mining cost by increasing powder factors. Not only is explosive energy cheaper than mechanical comminution energy requirements, the increased blasting effect may deliver benefits across all downstream processes of digging, hauling, crushing and milling. Kalgoorlie Consolidated Gold Mines (KCGM) Fimiston operation is the largest gold mine in Australia, located in the heart of the Kalgoorlie Goldfields. Blast dilution has been reduced at KCGM by managing location of blast boundaries and by firing along strike to choked faces. Significant economies of scale have resulted from application of a bulk mining methods. The bench height of 10 m is the largest in the Western Australian Goldfields, and is typically mined in a single pass with large face shovels. Recent increases in production rates in both the mine and mill has been partly attributed to a 30 per cent increase in powder factor. KCGM then examined the benefit of a further 18 per cent increase in powder factor to 1.0 kg/BCM. A concern though was the impact of very high powder factors resulting in excessive blast movement and subsequently ore dilution. This was the subject of a project conducted with Orica Explosives. OricaÆsDMC(Distinct Motion Code) blast model was applied to understand the effect of not just further increases in powder factor but also blast geometry and explosive type. The modeling work demonstrated that high powder factors may be applied with minimal increase in ore dilution provided the combination of blast geometry and explosive type is optimised. These results are currently being implemented to achieve further reductions in total mining costs without a significant impact on recovery.

Jan 1, 2001

By M A. Tuck

Air blasts or wind blasts as they are termed in underground coal mining, occur in a number of types of underground mining where a void develops and the overlying or adjacent rock fails rapidly to allow the development of a high pressure air pulse. The effects of air blast vary widely from very low consequence to high consequence events causing multiple fatalities as occurred at North Parkes mine. The aim of this paper is to examine the phenomena of air blasts and the underlying parameters which determine the severity of the air blast event. A basic model under development is then detailed. The aim of the model is to determine the magnitude of the pressure pulse(s) developed during an air blast event. This, combined with a transient ventilation network analysis model will enable the airflows and associated pressure drops to be determined and allow the pressure pulse around the mine to be evaluated. The overall aim is to allow mining engineers and mine ventilation engineers to undertake a risk assessment of air blasts at individual mine sites, allowing working parameters to be changed to eliminate or reduce air blasts, or engineering controls to be developed to reduce the effects of air blasts.CITATION:Tuck, M A, 2013. Determining the pressure pulse for an air blast, in Proceedings The Australian Mine Ventilation Conference , pp 103-106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

The paper presents a brief history of endeavours to start a mining education programme which began in the days when Papua New Guinea's first large mine, at Panguna (Bougainville), was coming into production. The status of the Public Investment Programme in Mining Engineering and the facilities being created for the education and training of Papua New Guinean citizens in mining and mineral processing are also described. Future expansion plans are also detailed including those for the commencement of petroleum engineering and geological engineering which would include courses in mining geology, exploration geology, engineering geology and petroleum geology. The paper also looks at the manpower training requirements in the lower levels of mining industry such as pit foreman, blasting foreman and other similar positions. It stresses the need to start mining technical training programs at pre- employment level and at certificate level in a technical college, possibly Lae Technical Colleqe.

Jan 1, 1991

By R M. S Watsford, M Davis

In 2015, MMG Limited commenced further action to improve operating margins and establish a blueprint for future growth in the Australian environment. This action was taken in the context of weakening metal prices and high input costs that arose during the Australian minerals boom.MMG was formed in June 2009 following the purchase of the majority of assets of OZ Minerals Limited by China Minmetals Corporation (CMC) through its subsidiary China Minmetals Non-ferrous Metals Co Ltd (CMN).Since formation MMG has been implementing a business model to deliver a standard way of operating. The overarching purpose of the business model is to enable fast integration of acquired assets to realise improved productivity and performance. CMN established MMG as a vehicle to reach their growth targets through further development or acquisition of mineral assets in jurisdictions external to mainland China.The business model is underpinned by the MMG operating model. The operating model defines how MMG is arranged to deliver the company strategy.This paper describes the application of the operating model to the formation of the Australian operations into a single business unit from multiple stand-alone operating sites. The development and impact of the business model on MMG’s performance is also presented.The extension of the operating model to the Australian operations has led to improvement in safety performance, direct costs and productivity. These improvements have been achieved through reducing duplication, simplification of systems and rapid deployment of improvement initiatives.The successful implementation of the operating model to Australian operations strengthens the platform for further growth. Hence, delivering on the aim of the business model.CITATION:Watsford, R M S and Davis, M, 2016. MMG’s Australian operating model – the implementation, successes and learning, in Proceedings International Mine Management Conference, pp 291-302 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By Pupazzoni P. D, Meissner D. C

Incorporating an iron ore pelletising plant, a MIDREX'"' Direct Reduction Plant, and a mini mill, the conversion of iron ore fines to high- quality steel slabs in Western Australia is among the lowest cost routes in the world. The cost and availability of iron ore and natural gas, government support, and proximity to the growing Southeast Asian market all contribute to the competitive position of the area. Owing to the lead-time required, this is an ideal time to develop a new project to supply semi-finished steel to Asia for rolling to a finished product. A project contracted now will start up in about three years, when the market should have recovered.

Jan 1, 1999