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By W Ilahi

Underground metalliferous mining methods often result in the formation of vertical openings to facilitate the extraction of orebodies. These development and production techniques can result in the creation of vertical open voids, which include stopes, orepasses, ventilation raises and other excavations. There are risks associated with the use of mobile plant in the vicinity of these voids, especially during backfilling and when bunds are constructed at the edge of a stope or void. These voids can present unacceptable risks if not adequately managed.

May 5, 2022

By T A. Carter

In 2010 Agnew Gold Mine (AGM) struggled to produce the required tonnages from its stopes. The longhole rises used to create void in stopes were unreliable and often failed to gain the designed rise height. The number of firings per stope was having an adverse impact on the ground conditions at the stope brows, impeding stope productivity.Through practical experimentation with longhole drill rigs, box hole rigs and development drill rigs as well as trialling new methods in conjunction with reviewing drill hole data, drill hole accuracy was observed to be an issue on-site. Innovative dragging methods such as the reverse drag, combined with a slope instead of a vertical face on the rear of stopes, have improved dragging and a reduction of firings per stope, enabling larger production blasts.The methods trialled and subsequently implemented at AGM have facilitated the mine achieving budgeted targets for six consecutive quarters. This paper documents the use of these methods in a key lode of AGM’s operations to improve drill and blast practices in order to achieve production targets.CITATION:Carter, T A, 2014. Improving production drilling and blasting in the Kim South orebody at Agnew Gold Mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 251–258 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

A new classification of subduction related (epithermal- / mesother-mal) gold mineralisation styles based on the tectonic framework they occur in, has been found helpful in practice. It offers a ratio-nalisation of exploration efforts during all stages of work.Methodology on the ground during first pass- and follow up explo-ration which has been found effective for the various mineralisa-tion styles is being briefly outlined.

Jan 1, 1990

By E J. Coyle, L A. Millington

Tailings storage facilities are geotechnically complicated structures that develop heterogeneous strength profiles and varied porewater conditions. The monitoring of porewater pressures is one of the only direct measurements that can be performed to monitor the performance of a facility throughout its life and is of particular importance in upstream facilities. Foundation underdrainage, continuous and staged tailings deposition, climate inputs (rain, snow, humidity, evaporation, etc), and stratified tailings permeabilities can complicate this critical measurement that introduces uncertainty to stability analyses. These difficult conditions manifest in vibrating wire piezometer measurements as very low or negative pressure readings, both of which are within the instrument’s range of accuracy. However, the data can be difficult to interpret, and a range of interpretations are adopted from optimistic low phreatic surfaces to conservative fully saturated tailings. Where tailings are potentially liquefiable, these very low readings introduce further uncertainty regarding the pore space saturation ratio and liquefaction potential above the estimated phreatic surface. This area of uncertainty is the vadose zone, and its affect on tailings behaviour is not well understood. The two facilities analysed in this paper are upstream, raised embankments with tailings classified as clayey, sandy silt that have been found to be potentially liquefiable. The vibrating wire piezometers (VWP) at both sites show very low or negative readings when they are initially installed near the surface and then go through cycles of re-saturation and de-saturation. Eventually the readings settle as the VWPs are buried deeper within the tailings. The instrumented sections within the tailings column do not show consistent readings that would be indicative of a hydrostatic phreatic surface at either site. Rather, they are highly variable and can be interpreted as either representing a high phreatic surface within the tailings or as a ‘perched’ phreatic zone within the tailings layers. How the VWP data is interpreted has a significant impact on how the facilities are raised and operated. The design outcome for Site 1, which adopts a lower phreatic surface, results in an embankment that meets factor of safety (FoS) requirements under residual strength conditions without any buttressing. Conversely, a conservative (high) phreatic surface has been adopted for Site 2 and has resulted in the facility requiring a significant buttress to meet FoS under residual strength conditions.

Jul 1, 2021

Interest in mineral sand mining in the south west corner of Western Australia began in the late 1940's and significant production commenced in 1956. Early land use conflicts arose because of conservation implications (Ludlow tuart forest), expanded to include post-mining rehabilitation requirements (the Wonnerup mine near Busselton) and today include some agricultural/mining disputes. These latter conflicts are largely caused by the need for mining companies to secure longer-term reserves. To date, deposits containing mineral valued at A$440 million have been sterilized and are unlikely to become available in the future. There is additional pressure being placed on presently available reserves and a pessimistic picture could be drawn, whereby the southwest mineral sands industry ceases to exist by the year 2010. However, sensible land use planning, the support of policticians and the community, and responsible attitudes towards compensation and rehabilitation could, in combination, see the industry maintain significant mineral output until the middle of the 21st century. Examples of deposits sterilized by adverse land use will be given.

Jan 1, 1986

By Christie AB

Stream sediment geochemical analyses from 140 mining company exploration surveys of the Coromandel, Northwest Nelson, Marlborough and Westland regions of New Zealand have been compiled from open file reports and entered on a database called REGCHEM (for Regional Exploration GeoCHEMistry). REGCHEM is supported by GEOEXPL, a custom-written computer software application which operates under the Microsoft Access relational database mangement system on a PC-type computer. The data are plotted as maps using the Maplnfo geographic information system (GIS) package. Thesholds separating anomolous values from background values are determined using the PROBPLOT univariant statistical package, which enables the descrimination and modelling of several populations. Relevant REGCHEM data are being incorporated into a GIS for the Coromandel region as part of ongoing studies to sevelop mineral deposit and metallogenic models for the region, and to assess regional prospectivity.]

Jan 1, 1995

By J Joughin, D Kyan, L Rollin

In line with the 2015 Paris Agreement and corresponding climate disclosure requirements, many mining companies have publicly disclosed that they are developing and/or implementing ambitious decarbonisation strategies. Sometimes these strategies can be linked to the development of community programs and/or the creation of a positive legacy post-closure. Renewable power is key to most decarbonisation strategies – some mines will get this from external sources and others will establish on-site power generation and storage facilities. A range of options are available to develop renewable power generation (eg solar panel, wind farm, hydropower) and energy storage (eg battery, hydrogen, pumped hydroelectricity). Land access, impact assessments, planning and environmental approvals are required to establish new facilities. Host communities are more likely to be in favour of, or at least will accommodate, new power supply developments if these are planned with a benefit to the communities. Transitioning to renewables raises new challenges. Among these are high upfront costs and access to capital, energy demand variability, supply intermittency and variability, storage limitations, grid stability and reliability, transmission and distribution infrastructure constraints. Compounding these challenges are issues such as infrastructure resilience to extreme weather events (eg heat, wind), land use and access, lengthy permitting processes, community perceptions, skilled labour requirements, and meeting mine closure objectives. Renewable energy sources provide a more decentralised source of energy that reduces reliance on imported fuels, thereby increasing energy security and lowering production costs. On the contrary, implementing renewable energy could lead to potential negative impacts such as visual perception from the community, competitive land usage, electricity price raises due to upgrading infrastructure and the use of electricity storage capacities. As part of the definition of an environmental and social management plan, participative stakeholder engagement is required to identify benefits to the communities. For example, among the recognised benefits of developing solar panels (increase job opportunities, reduce soil erosion), various technologies have been experimented globally for the last ten years and are emerging due to their proven community benefits. Key findings to enhance those benefits can range from the development of innovative practices such as ‘agri-/aqua-voltaic’, ‘solar grazing’ to optimise land usage and stimulate the local economy (Table 1), to the implementation of technologies providing services to communities such as mobile water desalination plants or ‘smart grid’ systems to minimise energy clipping during peak-load of oversized renewable energy facilities (Table 2). While developing those synergies, careful management is required to avoid creating superfluous energy service needs from community programs. Energy sufficiency should remain a key principle according to the sufficiency, efficiency and renewable framework of the Intergovernmental Panel on Climate Change. Darby and Fawcett (2018) define energy sufficiency has ‘a state in which people’s basic needs for energy services are met equitably and ecological limits are respected’. Sufficiency tackles the causes of the environmental impacts of human activities by avoiding the demand for energy and materials over the life cycle of buildings and goods. Efficiency tackles the symptoms of the environmental impacts of human activities by improving energy and material intensities. The third pillar, renewables, tackles the consequences of the environmental impacts of human activities by reducing the carbon intensity of energy supply (Cabeza et al, 2022). Life of Mine Conference 2023 | Brisbane, Australia | 2–4 August 2023 34 This paper provides project developers, decision-makers and regulatory authorities with ideas on synergies between renewable energy options and community development programs. These can be considered to enhance stakeholders’ support for implementation of decarbonisation strategies.

Aug 2, 2023

This paper reviews the manpower requirements of the Australian mining industry. It has been necessary to provide general background information in order to support the view that university education in mining and mineral process engineering should be strengthened rapidly in Australia to provide graduates for the industry.

Jan 1, 1969

By M Lak, R Amiri, A Haratian, M Asghari, S Haji

In recent years, due to advances in designing of various magnet assemblies, a wide range of magnetic materials with different properties can be concentrated. Jalal Abad iron ore beneficiation plant, which is located in Iran, Kerman province, is currently producing iron ore concentrate with the capacity of 0.8 Mt/a by having medium intensity magnetic separators (MIMS) with rougher and cleaner stages that finally leads to the production of an iron concentrate with the Fe grade of about 65 per cent. In this plant, the rougher tailings directly goes to the thickener as the final tailings and cleaner tailings feeds to the ball mill for regrinding. Since some hematite particles with weak magnetic properties cannot be recovered from only these two stages of magnetic separation, the obtained tailings from this concentration plant has approximately an iron grade of 25 per cent to 27 per cent. Accordingly, laboratory processing tests were conducted on the obtained representative sample of the final tailings. Based on the experimental results performed on final tailings, a new magnetic drum separator with a specific magnetic assembly was designed that could finally lead to product with iron grade range of 58 per cent to 60 per cent with relative and total weight per cent of 8.6 per cent and 3.86 per cent. Finally, it could be concluded that feeding of magnetite particles to the existing drum separators, due to their high magnetic field intensity, cannot efficiently lead to improvement of the grade of concentrate. Therefore, pilot magnetic separation tests were done on the final concentrate for evaluation of product upgrading probability. Consequently, by increasing another stage of cleaning and by decreasing the magnetic field intensity, the final product grade could be enhanced from 65 per cent to 67 per cent.

Nov 8, 2021

By Eggleton R. A, Taylor G

As the search for major orebodies continues, the regolith dominated areas of the Broken Hill region remain one of the major exploration frontiers. The past exploration philosophies emphasising bedrock related characteristics have been limited in their ability to effectively explore in the regolith dominated areas, that are a feature of most of the Broken Hill region (Figure 1). If mineral exploration is to be more effective across all of the Broken Hill region, particularly in the regolith dominated areas, an appreciation and increased understanding of the regolith and landscape features are a necessity. Ironically, there have been very few studies of the regional regolith and landscape features of this region. Owing to the previous lack of an established regolith-landform framework, this study initially concentrated on the general characterisation and variation in regolith types corresponding to the area of the Broken Hill Block, within NSW (Willis, 1989; Stevens, 1986). The approach has been to produce a regional regolith-landform map at 1:100 000 scale and conduct a complimentary program of regolith sampling and site descriptions. This was a basis to identify areas for more detailed regolith-landform mapping (1:25 000 scale) and for producing a regional stratigraphic framework and models for landscape and regolith evolution. This information can then be used to provide a basis for regional mineral exploration models and strategies. This paper highlights some of the regionally significant regolith-landform features and their general significance to mineral exploration. More detailed information on specific regolith-landform features and study sites may be found in Hill et al (1994; 1996; in press) and Hill (in prep).

Jan 1, 1997

By A Weston

Northparkes Mines is a joint venture between Rio Tinto and the Sumitomo group and is operated by Rio Tinto to produce copper concentrate from ore sourced from open cut and underground. Underground ore is mined with an owner operator workforce using the block cave method from the E26 deposit, with the first lift of the cave now completed. Development of the Lift 2 block cave commenced in March 2001 using a contract workforce. The Lift 2 Project required the mining of 14 700 m of decline and lateral development to establish a new mining horizon at the 9450 level and to develop two new conveyor declines. Also included in the scope was the excavation of a Crusher chamber to house the jaw-gyratory crusher. This paper describes the excavation of the hydroset chamber and orepass that sit immediately underneath the Lift 2 Crusher chamber. It includes risk assessment, planning, development of method statements and standard operating procedures, through to the excavation of the orepass and the installation of ground support in seismically active ground. There was a major ground failure in the backs of the conveyor feeder chamber during its excavation, which affected the excavation of the orepass due to its proximity to the breakthrough site.

Jan 1, 2005

By Z Lubosik, S Prusek, M Plonka, B Syrek

"The most commonly used method of thick coal seam extraction in Polish deep mines is multislice longwall (MSL). In MSL stability of goaf in the roof as a result of previous extraction in upper slice is a major geotechnical consideration that must be managed.This paper outlines the results of a wide range of investigations carried out in three longwalls that were in operation in a multislice system using caving with additional fly ash goaf stowing. The longwalls were operated by Katowicki Holding Weglowy SA (KHWSA) in the Upper Silesian Coal Basin of Poland.Examinations were completed on the properties of goaf at the roof of longwalls ie measurements of strength parameters of the goaf material by means of a borehole hydraulic penetrometer, determination of the goaf condition by means of a borehole endoscope and laboratory testing of the caved rock. The results of underground examinations of the loading on yielding arches in the gate roads associated with these longwalls and measurements of vertical and horizontal convergence are also presented.CITATION:Prusek, S, Lubosik, Z, Plonka, M and Syrek, B, 2014. Multislice longwalling for thick seam extraction – properties of goaf in the roof and gate roads behaviour, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 359–366 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By Richards RG

The Australian glass sand industry produces some 2.8 million tonnes per annum of silica sand, of which about 2.0 million tonnes are exported and the rest is for the domestic market. Approximate production rates for each Australian state are listed.The variety of processing methods used in the currently exploited deposits reflects the size, location, and characteristics of the various deposits and the requirement of the end market/s. The industry uses to a large extent equipment developed for the separation of mineral sands, particularly as it applies to low grade heavy mineral deposits, where low cost, high capacity and metallurgically efficient equipment has proved eminently suitable for the production of the low value glass sands.The requirements of the domestic market, as well as those of the present and potential export markets are discussed covering quality requirements, distribution channels and other factors critical to success.

Jan 1, 1990

By Y-B Kang, J H. Park, J Park

In order to understand the effect of oxygen injection into the molten metal on the valuable metals (VM) recovery and interfacial phenomena, several high-temperature experiments were conducted using a high-frequency induction furnace with a quartz tube as the reaction chamber at 1673 K. Copper-based waste printed circuit board (PCB) that contains some impurities was selected as the end-of-life resource. CaO-SiO2 based pre-fused slag and oxygen gas were used in present works. The composition change and microstructure of the samples were analysed. As oxygen was injected into the system, impurities were rapidly removed. After the removal of impurities, continuously injected oxygen lowered interfacial tension between liquid slag and liquid metal. Lowered interfacial tension induced Cu loss into the slag.

Aug 21, 2024

By M P. Cipold, J F. Bachmann, C C. Bachmann, J Ha

Knowledge of fuel qualities is of ultimate importance for the efficiency of chemical plants or power stations. Although most blending yards are equipped with automatic samplers and the derived samples are processed in the laboratory, the quality variation of the blended product may still be strong. This is caused by several reasons. First of all the process of sampling, crushing, dividing and analysis is time consuming. Results are available only with a delay of two to 24 hours. During this time blending is operated without knowledge of the main parameters. Conveyors with high throughput require expensive sampling systems capable of handling samples which are representative. The frequency of sampling needs also to be high in order to be representative. This results in high maintenance costs and also downtime of the sampling system.Online analysis of bulk materials has matured over time and today it can supplement but not replace laboratory analysis. As an example, J&C Bachmann has realised a coal quality monitoring system on the coal supply of a South African coal processing plant. The plant consumes ~42 Mt of coal per annum. The blending yard consists of two sets of three heaps where coal of six different mines is blended according to the factory’s requirement. From there, the blended coal is fed to the factory on two different belts.In 2010 the plant installed a TEXAS X-ray fluorescence analyser as a trial. It was tested under different conditions on several belts before the customer decided to install six TEXAS analysers on the feed belts to the stackers and two more analysers on the reclaimer belts. All analysers are installed directly on the belt and not on a substream.During the test period blending strategies were developed in close cooperation between the customer and J&C Bachmann. The use of the analysers in conjunction with the blending model has proven that the variation of the reclaimed coal quality was decreased significantly, which results in increased process performance and significant cost savings.CITATION:Bachmann, C C, Bachmann, J F, Cipold, M P and Ha, J, 2017. Online quality control of a coal blending yard, in Proceedings Eighth World Conference on Sampling and Blending , pp 125–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

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 K Clode, J Al-Shdifat, S Daykin

Planning for a circular economy allows for previously untapped market opportunities to be explored, resulting in new, innovative revenue generating opportunities, while also reducing environmental impacts. In particular, rare earth elements (REE) are in rising demand as they are key components of over 200 products across a wide range of applications (Xie et al, 2023) including renewable energy technologies. There is a geographical disparity in deposits, with China being the top producer, generating 70 per cent of global production in 2022 (Laboure, 2023). This single dominating source has created supply chain concentration and hence supply risks for other nations, providing a driver for finding alternative sources, such as mine-influenced water (MIW) and tailings. In this study, Isle presents a robust due diligence methodology for undertaking a global horizon scan into REE recovery technology, for a large mining company, from tailings decant water on a specific site. Previous studies of the tailings decant water at this site had shown potentially significant concentrations of both heavy and light REE, but challenges such as high flow, very low pH and high concentrations of iron had previously made recovery unfeasible. Due to these challenges, the horizon scan focused on technologies that had the potential for selective recovery, despite the challenges with water quality, and considered a range of Technology Readiness Levels (TRLs). This included an adsorption-based process that has the potential to selectively separate individual REE, and a polymer based selective flocculation technology.

Sep 1, 2024

Brunswick Mine, one of the largest underground zinc mines in the world, is scheduled to close in 2010 after almost half a century of production. All mines eventually close; some suddenly as a result of unsustainable economic or technical conditions and others, as in our case, as a result of the depletion of the orebody. When the mine is the most significant employer and an economic driver in the region, it is key that the closure is handled in a planned, communicated, well-executed fashion. The following paper documents strategies, plans and activities that are currently taking place in order to ensure a seamless closure that satisfies all stakeholders including employees, management, regulatory bodies and the public. It is an important deliverable for the company that the good will, credibility and reputation that has been built up over the years is sustained throughout the closure process and beyond. A life of mine labour agreement with the unionised workforce, staff retention and recruiting programs, regulatory closure plans, communications and transition adjustment activities will be discussed. The use of a stage-gate style project management tool analysing the risks and key deliverables will be highlighted. It is hoped that the concepts and approaches discussed here may be of value to other operations that will be faced with closure, and its inherent challenges, in the not too distant future.

Jan 1, 2006

Resue or split face firing has the potential to separate ore and waste rock into separate muck piles within a stope. Thus split face firing has the potential to reduce dilution of the ore stream to be transported to the surface for subsequent processing. It also potentially reduces the total amount of broken rock needing to be transported out of the mine as the waste material is physically separated from the ore as part of the blasting process. Waste can therefore be used directly from the stope to backfi ll other mining areas. This paper reports on the results of split face firing trials at the Hillgrove mine in NSW and analyses the results of these blasts.

Aug 1, 2010

By R Grogan

Nautilus Minerals (Nautilus) is a sea floor resource exploration and development company focused on developing the Solwara 1 Project, a copper-gold sea floor massive sulfide deposit in the territorial waters of Papua New Guinea, for which it holds a mining lease and associated environment permit.During the environmental impact assessment and project development phase, Nautilus completed a number of hydrodynamic modelling exercises in order to predict the nature, volume and extent of the plumes likely to be generated by the sea floor mining tools and return water discharge at the sea floor.The modelling was conducted using the suspended sediment fate model (SSFATE), developed by the United States Army Corps of Engineers and RPS APASA engineering consultants. The SSFATE model was originally developed in order to predict and manage dredging plumes, and has since been adapted for deep ocean sea floor mining. The model uses a Lagrangian approach to remove the limitations of grid resolution, and simulates far-field effects of sedimentation plumes by assuming that the average transport and turbulence associated with currents are dominant over the initial turbulence at the release point. The random walk procedure utilised in the model tracks particle size classes as they disperse and settle, and also takes into consideration any re-suspension that may occur following settlement (RPS APASA, 2014).CITATION:Grogan, R, 2016. Predicting, assessing and managing sediment plumes generated by sea floor mining, in Proceedings Life-of-Mine 2016 Conference, pp 124–127 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016