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By D Craw

The Macraes gold deposit is located in a low angle NE dipping (~15¦) shear zone, the Hyde Macraes Shear Zone (HMSZ) cutting greenschist facies metasediments of the Otago Schist. The shear zone is host to large volumes of mineralised schist and relatively sparse quartz veins. Early in the development of this through going shear the schist experienced an episode of hydro fracturing and fluid redistribution. As a result, presently exposed schists within the Intrashear sequence are pervaded by localised swarms of quartz filled pure extension and extensional shear fractures hosting goldscheelite mineralization. The swarms comprise networks or æstockworksÆ of veins that strike NE, are subvertical and form subperpendicular to the shear zone fabric. Vein frequency across strike is typically ~1 m-1, with most veins five to ten centimetres thick and vertically continuous for up to ~20 m. Many of the veins show delicately banded internal textures that are parallel to the vein margins. These bands/lamina indicate incremental growth and are defined by a variation in grain size or alternatively by thin slivers of wallrock schist, though typically uncommon. The majority of veins are overprinted by a weak plastic deformation, although primary structures are largely preserved. This deformation has produced subgrain structures, migration of grain boundaries with sutured margins and undulose extinction of grains. These microstructural observations possibly indicate that temperatures were around 300¦C during stockwork vein formation. In general, the mode of brittle failure that developed the stockwork veins can be directly related to lithological variation. The geometry of stockwork veins indicate that local vertical shortening and extension occurred in the Intrashear sequence of the HMSZ synkinematically with thrusting. Localised extension was mainly parallel to the structural trend; that is, it took place perpendicular to the direction of inferred thrusting. The development of lateral ramps most likely gave rise to extension in parts of the shear zone during continuous shortening to form swarms of stockwork veins.

Jan 1, 2004

By O Arafat, R E. McIvor, K M. Bartholomew

It is well known in the industry that good classification system performance is vital to efficient ball mill circuit performance. But what is meant by good classification system performance, and how is it achieved? Unfortunately, the perceived complexity of classification systems, and the day-to-day time demands placed on the practicing metallurgist, all too often put the low-hanging fruit of classification system optimisation in the ‘I’ll do it later’ basket. Additionally, lingering confusion about basics such as the relationship between circulating load ratio and ball mill circuit performance makes the optimisation objective seem nebulous to both plant metallurgist and designer.Some of this confusion can be eliminated by taking a step back from the overwhelming detail of sharpness of separation curves, circulating load ratios, cyclone feed pressures, vortex and apex sizes etc, and focusing on the purpose or function of the classification system – to apply mill power to particles that need further size reduction! The classification system efficiency (CSE) metric captures how well the classification system is performing its function with two quick and easy size distribution analyses.Once CSE is understood and implemented as the optimisation criteria, well-tested methods for improving CSE can be implemented and quickly measured at plant scale to give confidence that the right change was made.This paper will describe CSE and how it is measured in practice. Next, a guide for improving CSE through manipulation of design and operating variables in the classification system will be provided. Examples and case studies will illustrate the gains in ball mill circuit efficiency that can be achieved by maximising CSE.CITATION:Bartholomew, K M, McIvor, R E and Arafat, O, 2018. A guide to maximising ball mill circuit classification system efficiency (CSE), for operators and equipment designers, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 553–558 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Griffiths L, Marshall P

fhis paper describes investigations into drainage of gas from the solid to control outbursts. Initial studies conducted on drainage of shear zones showed that, given enough time, these can be successfully drained. Once drained, they can be intersected and driven through without any activity of outbursts. The results of programme of investigations to determine parameters for drainage from the solid show that gas flow rates from the Bulli Seam on the average are about 2 litres/min/metre length of borehole. But when shear zones are intersected, the flow rates could be as high as 8 litres/min/ metre length of hole. Shear zones can be picked up from pressure measurements 50 - 60 m away and this could give sufficient time to drill through these zones and drain them in advance. Systematic drainage of Bulli Seam at West Cliff Colliery could eliminate or reduce frequency of outbursts considerably. At present drainage holes are being drilled systematically in the seam, with drainage installations on the surface. Gas purity of 80% methane is being delivered at the surface plant.

Jan 1, 1980

Control of construction projects is the responsibility of the Project Leaders who have the authority to make decisions. Project Controls cost and scheduling systems provide the Leaders with timely information on which to base their decisions.The Client (Owner) will invest up to three per cent of the project cost on Project Controls. To ensure that this investment is effective, the Owner or Manager must have a clear understanding of the information required from the Project controls systems. If appointing a single Managing Contractor, the Owner or Manager must stipulate what is and what is not required from the Project Controls Systems. There are numerous computer programs available for scheduling and cost control and it is important to select systems which best serve the Owner's needs.

Jan 1, 1993

By P Guj, J A. Bell

The valuation of early-stage exploration projects requires a valuer to take into account a large number of uncertain value drivers, the interplay among which may be non-linear. This paper examines some of the key value drivers including geology, target metrics, project area and maturity, the market and the psychology behind the decision-making process. The commonly accepted valuation methods and their underlying logic are outlined, including a view on why they evolved, what value drivers they attempt to address and their potential shortcomings. These methods include the multiple of exploration expenditure, geoscience rating, expected values and market based methods. The potential future valuation methods of replacement values and neural networks are also introduced along with how to minimise heuristic bias and error within the market-based approach.CITATION:Bell, J A and Guj, P, 2012. Exploration value drivers and methodologies, in Proceedings Project Evaluation 2012 , pp 17-28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By T Amiconi

Ernest Henry Mining commenced operations on its copper-gold project in August 1997, some two months ahead of schedule and ten per cent ($35 million) under budget. The mine is located in the highly prospective Mount Isa/Cloncurry mineral district in north-west Queensland, approximately 38 km north-east of Cloncurry. The developer and operator of the project is Ernest Henry Mining Pty Ltd (EHM), an incorporated joint venture between MIM Holdings Limited (51 per cent) and Savage Resources Limited (49 per cent). The deposit is located approximately 40 km north of Cloncurry in North West Queensland and lies beneath a featureless black soil plain with no significant creeks or gullies cutting across the site. Vegetation is sparse and consists essentially of Mitchell grass with occasional low shrubs and trees. Up to nine million tonnes of ore and over 43 million tonnes of waste will be extracted each year from an open pit operation to produce approximately 350 000 tonnes of concentrate when in full production.

Jan 1, 1998

By P Cleary, G K. Robinson, J Hilton, P Wilson

Concern has been expressed that Vezins can be biased when used for sampling fine materials if the cutter speed is as high as the 0.6 m/s which is often used. Using modelling techniques that consider airflow as well as particles, we have endeavoured to investigate sampling bias as a function of the size of fine particles, cutter aperture, cutter speed, shape of cutter blades, and the size of the gap between the inlet pipe and the cutter blades. Using crude estimates of the rate of airflow and a simple model of a single particle moving through air led to an approximate rule that bias will not occur due to mechanisms related to airflow for particles larger than about 200 microns; and bias will always occur for particles smaller than about 40 microns. For particles between these size limits, the extent of bias depends on particle density, cutter speed and cutter geometry as well as particle size.CITATION:Robinson, G K, Wilson, P, Hilton, J and Cleary, P, 2012. Avoiding bias when using vezins for sampling dusty materials, in Proceedings Sampling 2012 , pp 109-114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By J Bassan

The mining industry is faced with imperatives to improve worker safety and productivity, adapt to skills shortages, high worker turnover rates, and provide more effective maintenance to new and ever more complicated plant and equipment. While more effective use of data combined with advanced analytics offers opportunities for improvement, providing this information to the worker in the field, in real-time, has proven expensive, cumbersome and ineffective. New capabilities are now emerging which address some of the limitations experienced to date. Augmented reality (AR) provides a means to overlay interactive digital information on top of the physical world. Combining the latest visual display, mobile computing and ‘track and trace’ technologies, AR provides an experience similar to a heads-up display in a fighter jet through small, personnel devices, such as smart phones or wearable glasses. Applying AR would allow a mobile worker to ‘see’ all relevant information for a given task, in the context of their physical environment and at the time they require it. The technologies behind AR are rapidly maturing and becoming available at a price point that is viable for commercial applications. It is anticipated that AR will become ubiquitous at a consumer level within the next five years. The specific challenges faced by the mining industry make it an ideal early adopter of AR technologies. This paper examines a number of use-cases of how AR can be applied to the mining industry and the benefits that can be realised. The paper will identify areas of further work and viable opportunities for immediate adoption within the industry.

Nov 22, 2011

The mineral processing industry is in boom times. The focus on mill availability and therefore profitability has never been greater, as grinding mill maintenance often dictates the entire plant shut down duration. Advances in mill systemsÆ quality and reliability and the faster, safer relining afforded by RMEÆs Mill Relining Systems have significantly enhanced grinding plant availability and utilisation. Yet relining performance is still affected by the design and planning by a team of stakeholders long before the maintenance team set foot in the mill. For a greenfield grinding plant project, these team players include: 1. project owner, 2. project manager, 3. mill supplier, 4. liner supplier, 5. plant operating personnel, 6. plant maintenance personnel, 7. mill relining crew, and  8. mill reline system supplier (RME). The complex and sometimes competing design demands of mill construction and operation together with the pressure of tight timelines can result in even simple maintenance requirements being overlooked let alone optimising plant design and planning for maintenance. This paper identifies all the involved stakeholders in an effective mill relining 'team' and gives principles and considerations for each to more effectively achieve the goals within their vital roles. This paper is aimed to be a practical guide for grinding mill designers and planners to more fully exploit the advances in Mill Relining Systems and improve their mill profitability.

Jan 1, 2008

By K Cochrane

Time and time again history shows us that mine closures are sustainability failures. Mine operators do not know how to turn the mine closure into an asset and communities around the mine do not know how to plan or what to implement to be sustainable when the mine needs to close. If we want to achieve sustainability when we close a mine, we generally need to consider what economic activity we will have to create leading up to the mine closure to ensure that the communities remaining in the area are not worse off after mining than before. There is not one silver bullet solution to mine closure, as all mines are affected by different environmental and socio-economic conditions. That is one of the reasons why mine closure is so difficult.Effective stakeholder engagement is the nucleus around which sustainability is built. Achieving sustainability as part of mine closure means not only a self-sufficient community, but also could lead to transformation of that asset.A key issue is that neighbouring communities become completely reliant on the mine. The mine has influenced the economic, environmental and social aspects of the community and with no alternative economic sources. The community and municipality will struggle with capacity to maintain infrastructure, services and jobs. This not only impacts the mine workers and their families but also other businesses and people in the town that make a living by servicing the needs of the workers and their families. Social problems associated with a mining operations and closures need to be considered. The misuse of alcohol, domestic violence, breakdown in law and order, economic and health issues all have a severe influence. Families often need to relocate from the mining town to find work. This further perpetuates the impact of the mine closure to the economic viability of the town. CITATION:Cochrane, K, 2018. Is your mine closure a sustainability failure? Transform your asset and create a self supporting neighbouring community. It’s as easy as ABCD!, in Proceedings Life-of-Mine 2018, pp 38–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By J Webb

The mining industry is relatively niche and complex compared to other global industries in its safety and operating environment. Whilst some of the technology required to decarbonise the mining industry will emerge from the mass market (eg batteries, energy storage solutions and renewable power generation) where exogeneous external investment and innovation will drive supply, bespoke applications such as material movement will be constrained by industry limitations. Underground load and haul equipment burns the majority portion of underground mine diesel, and typically 25 per cent of scope one and two emissions. Transitioning away from incumbent diesel engines offers a considerable health benefit to all mine workers, as well as decarbonisation achievements, and through trials there is emerging evidence of more productive equipment and realistic expectations of lower operating costs of fleet. However, new equipment and material movement systems that support these industry goals are currently approached with caution due to the pivotal role they play in delivering productivity goals, and the lack of experiential data and certainty to mitigate the supplier development risk during this technology transition period, where all resources are required to meet a booming industry. A group of mining companies and suppliers have the aligned aim to accelerate the understanding and availability of heavy haulage mobile equipment through collaboratively piloting equipment and working with suppliers and each other to aggregate market demand, encourage investment and resolve the mine design and technology choices through their involvement in the Electric Mine Consortium (EMC). This paper will outline the major challenges the industry must overcome in sourcing and adopting a zero-diesel particulate and zero-emission mine, drawn from cases and insights across ten EMC mining company members.

Mar 29, 2023

By C Cavern, G Jacobs, F Durufle, L Ameglio

Airborne geophysics and geomatics is at a crossroads as to whether it remains a viable mapping tool, both technically and commercially, and broadens its potential for new applications (eg environmental monitoring, civil engineering and precision farming). The use of small and stable multisensor aerial platforms to conduct highly flexible surveys flown at a low/reasonable cost of operation is a recurrent wish of many stakeholders in the natural resources exploration and mining industry. Through its Fly Light Airborne Geophysics research program, EXIGE and partners have pushed the development and testing of two new airborne carriers with unique capabilities for geo-surveys: GyroLAG’s gyrocopter and Infotron’s unmanned aerial vehicle (UAV). These carriers are the next generation of versatile and innovative aerial vehicles for remote sensing and monitoring. They are rotary, smart tailored, ultra-high resolution manned (gyrocopter) or autonomous (UAV) airborne platforms that combine the merits of dense data sampling, accurate position location, very low clearance above ground or sea level, slow speed, interchangeable and combined multiple geo-sensors, automatic data quality control and real-time quality assurance. They also have the benefits of being highly efficient, cost-effective, commercially attractive, safe, reliable and easy to deploy and operate. Their technical specifications and multiple advantages compared to traditional aircraft and/or ground crews are presented in this paper. An overview of various geo-sensors (magnetic, gamma-spectrometry, visual, near-infrared and LiDAR) carried on-board is also provided.CITATION:Ameglio, L, Durufle, F, Jacobs, G and Cavern, C, 2015. Light airborne platforms for monitoring mines and minerals, in Proceedings Third International Future Mining Conference, pp 11–20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

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

The underground mining of a narrow vein hard rock orebody is a capital and labour intensive method of extraction. Due to the nature of underground mining it is difficult for higher level managers to physically see the efficiencies and inefficiencies of a particular method. Extraction methods and sequencing often need to be altered from the original planned methods as a result of mine developent, providing more in depth information as it progresses. As a result of these issues contract mining of these orebodies is common practice. There are several types of contract structures for the purpose of underground contract mining with many complex permutations of them that reflect the different needs of each individual company and orebody. The different contracts are arranged dependent on the mining companyÆs desire to transfer or, alternatively, embrace risk. This presentation gives a brief overview on these different methods and their various advantages and limitations with regard to small scale and narrow vein underground mining. With respect to these different contracting methods, the presenter reviews the mutual growth benefits of emerging partnering opportunities, specifically with regard to smaller explorers exploring and developing prospective mining tenements. The specific advantages to small explorers include the resource flexibility and speed of project development that private mining contractors can provide. Given the contracting methods that are available, there is potential for small private mining companies to gain minor stakes in major projects and major stakes in medium sized projects by employing innovative contracting solutions to provide mutual benefits to the parties. Some potential scenarios to this effect are suggested in the presentation. This paper is available as a PowerPoint presentation only.

Jan 1, 2006

By T Wang, D Wang

Photogrammetry-based techniques supported by traditional mapping tools are more frequently used for open pit geotechnical mapping. It fundamentally involves the collection of geological, structural and rock mass data from pit batters when safe to do so. These are essential components for refining and implementing continuous improvements to geotechnical models. The geotechnical model is used to review bench performance, optimise geotechnical design parameters, interpretation and analysis of pit slope stability. This paper is a case study of implementing different pit mapping methods at Mount Carlton gold mine, North Queensland. It critically reviews the tools required, including the Brunton compass, mobile application Clino, geotechnical data mapping software CloudCompare (2015) and Sirovision software. The review compares the image precision, structural measurements and data analysis. The review also underlines mine site management philosophy for safe geotechnical data collection to identify in-pit geotechnical hazards and the mitigation of potential slope instability. Sirovision is a remote sensing system for site geology mapping and interpreting geotechnical characteristics of exposed mining faces. The system utilises off-the-shelf digital SLR cameras to capture stereo photographs of the rock face and uses the latest image processing technology to generate accurate 3D models. These 3D models are digitally analysed using computational geometry to extract unbiased and accurate geological and geotechnical data. CloudCompare processes high accuracy 3D dense cloud rock surfaces reconstructed with photogrammetry software to extract the geological planes using the FACET or Compass plugins. The major discontinuity sets can be observed and the orientation (dip/dip direction) obtained from the algorithm is accurate and reliable for geotechnical assessment, including kinematic and rock slope stability analysis.

Nov 29, 2022

By U König, N Norberg

Traditionally, quality control of iron sinter has relied on time-consuming wet chemistry. However, the mineralogical composition that defines the physical properties, such as strength or reducibility, is not monitored.X-ray diffraction (XRD) analysis in combination with Rietveld quantification and statistical data evaluation using partial least squares regression (PLSR) has been successfully trialled to determine the mineralogical composition and process parameters such as the FeO (Fe2+) content and basicity of iron sinter within an analysis time of less than eight minutes per sample. The results were compared with wet chemistry data.PLSR does not require pure phases, crystal structures or complex modelling of peak shapes. The analysis is therefore easy to set up and ideal if only one property needs to be analysed. PLSR results show an accuracy for the FeO content of ±0.3 per cent for the samples analysed in this case study.Both the PLSR and Rietveld methods take the full XRD pattern into account and can be simultaneously applied on the same measurement. PLSR was found to be the more robust method if only FeO and basicity results are required. The Rietveld method helps to predict other parameters, such as the compression strength of the sinter, by monitoring all existing phases (eg larnite C2S or silico-ferrite of calcium and aluminium phases).CITATION:König, U and Norberg, N, 2015. Iron sinter process control using x-ray diffraction, in Proceedings Iron Ore 2015, pp 53–60 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By C Killip

Working in Australia’s harsh climate can have a significant impact on the health, safety and productivity of our teams, but is our working environment expected to be more prone to heat stress in the future? Climate modelling suggests that we are likely to encounter more frequent heatwaves and higher apparent temperature. Does this mean that our teams will be at greater risk of heat stress, and are we prepared to deal with the changes in our future climate and the potential impacts on our working population? This paper will review the recent research on climate and projected changes to all meteorological parameters that are important in understanding the likelihood of heat stress. The paper will also describe the challenges encountered in the management of heat stress in a workforce, and then outline a systematic approach to heat stress management that will allow you to assess your own risk and manage your day-to-day operations into the future.CITATION:Killip, C, 2015. Future climate – is heat stress a real risk for the future and how can we better manage it?, in Proceedings Third International Future Mining Conference, pp 181–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By Dinuzzo P, Wychie J, Desoe C

The Selwyn Gold-Copper Mine is located 150 km southeast of Mount Isa within Proterozoic units of the Mount Isa inlier (Figure 1). Mineralization in the mine area is associated with strongly sheared ironstones and iron rich schists at the base of the mid- Proterozoic Staveley Formation. The ironstone horizons outcrop as a series of dominant ridges over a 10 km strike. Economic gold-copper mineralization has been defined in 4 separate zones within a 3.5 km length of the outcropping ridges. A current combined geological resource for the deposits is 5.3 million tonnes of 5.0 g/t Au and 2.02 Cu. Weathering of the deposits has resulted in a pronounced vertical zonation of mineralogy, especially copper, within the ore zones. This has produced 3 separate ore types which require different treatment techniques. The categorization is based on copper content and zones are termed leached (surface), oxide and sulfide. Ore removed from the pits will be mainly leached and oxidized with minor sulfide near the pits final depths, while the underground ore will be from the sulfide zone with minor oxide in some areas.

Jan 1, 1989

By Thompson M

The humble gabion basket is to mine development what the light bulb and safety pin are to eir-ryday life. Gabions provide a flexible, easy to assemble and cost efficient solution for "101" mine and civil engineering development applications.In some instances gabion baskets are still efficiently in use after many years of faithful, maintenance-free service. In other situations, the baskets have been demolished or made redundant within days, either having served their temporary usefulness or negligently destroyed by the operator of heavy equipment. Either way, the gabion basket must surely rate among the top 10 cost efficient engineering construction materials.

Jan 1, 1994

A new test coke oven of seven cubic foot capacity is described. The oven was designed to simulate conditions in a central section of a battery oven and a special feature is the achievement of unidirectional heating from the flues on either side of the charge. The method of charging permits close control of charge conditions'such as bulk density and moisture content. These conditions, as well as coking conditions (e.g. flue temper- atures., coking time) must be varied to simulate conditions in different batteries, The effects of several variables on coke quality are discussed. Using test oven conditions corresponding to those of Newcastle steelworks batteries, good agreement was obtained between strength indices of test oven and battery cokes; for 17 tests, the average A.S.T.M. stability and hardness indices for the test oven coke were 38,5% and 69.7%, while those for the battery coke were 37.1.% and 67.6%.

Jan 1, 1969