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By G J. Lyman

Sampling of grain for mycotoxins is challenging in that some mycotoxins, such as Ochratoxin A (OTA), have very low permitted levels and the kernels carrying the mycotoxin may be highly localised within the bulk of the grain as ‘hot spots’. Sampling for genetically modified organisms (GMOs) can be fraught with similar problems, especially if the contamination is adventitious and random. Incremental sampling under these circumstances can be shown to lead to a high variance in the sampling result.A new design of sampler for grain and other free-flowing particulates has been developed that is effective in practically eliminating the sampling variance due to distributional heterogeneity (DH).This paper introduces the design and argues that the sampler should be free of sampling variance due to DH.CITATION:Lyman, G J, 2017. A new sampler for grain and other free-flowing particulates, in Proceedings Eighth World Conference on Sampling and Blending , pp 277–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By D C. Ford

The Argyle AK1 orebody was discovered in 1979 and subsequently found to be a large, economically viable reserve with high grade diamondiferous ore. Production began via an open pit operation at the end of 1985 and has continued for some 25 years to present day. This, however, will come to an end in the next few years with production moving to an underground operation via block-cave mining methods.A series of studies from 2001 - 2005 was carried out; diamond drilling commenced after approval in 2006, from an exploration drive to determine the likelihood of the current proposed block cave operation.In 2006, development of the block cave project began, in order to realise the part of the orebody below the extent of the open pit mining operation.Development of the block cave technique, comprising an undercut level beneath the target zone of the orebody with subsequent extraction level 15 - 20 m beneath, relies largely on a number of block-caving parameters (hydraulic radius, rock type, structure and orientation of stress and grade of the orebody). These all have an influence on cave ability and eventual profit of the operation. Evaluation of further potential for taking this orebody beyond the block cave phase with options such as sublevel-caving are being considered for the UG-2 portion of the resource/reserve. Diamond drilling for this work is currently under revise.The challenges faced in transitioning form the surface operations to the underground, comprising a changing workforce, converging development drives, underground aquifers, major excavations and transportation of ore via automation are intriguing.

Aug 22, 2011

Manganese ore has been mined from the Peak Hill Gold- field since 1948 and from the Pi'lbaraòGoldfield since 1954, and it is probable that some deposits- In and, near the Phillips River Goldfield will be mined at a future date', There are also several million tons of mariganiferous ;naterial which is too low in manganese. .co.ntent_ for . present requirements. The manganese deposits¦of Western Australia are mostly superficial. They hav' been formed during the Cainozoic Era by supergene enrichment ò6f Precambbrian: manganiferoius sediments, and by deposition from -solution on, or'in caves in, the Cain- ozoic land surface. The manganese in solution was derived from the weathering of Precambrian manganifer.ous s.edimexsts, None of the deposits are of hydrothermal origin, nor are they related to igneous rocks in any war, other than as ultimate source rocks. There is ho evidence-'t.o.:sugge,st that meta- morphism has been responsible for.the emplacement of any deposit. The tenor of the ore varies'aec'ording'to the quantity of gangue in the orebody and- also to the nature of the part- icular ore minerals. The main ore.mine.rals are the oxides pyrolusite and cryptomelane and the 'o'xide-silicate braunite. The main gangue minerals are hematite, limonite and quartz. The deposits of high grade oreò(-above.45 per cent Mn) range in size from 50 tons to many thousands of tons but most of them are in the 500-5,000-tons r .nge .

Jan 1, 1964

By C Donnelly

Redpath Australia is using a unique mining method for the Australian underground coal industry at Kestrel Mine Extension in the Bowen Basin, Central Queensland.The project involves completing two separate drifts from the surface for access to the German Creek Coal Seam located approximately 230 m below the existing surface. The scope of work is primarily the construction of two drifts; the first is 1577 m at 1 in 6 gradient and the second 1874 m at 1 in 8 gradient. Each drift has been developed by a Mitsui S200 roadheader with modifications to allow for a continuous tunnelling/mining cycle operation. A shotcrete boom has been fitted to the left hand side of the machine with the operators console located at ground level. Another operators console is elevated on the right hand side of the machine to allow operation of the rotary drill boom which is mounted on a slide rail to allow flexibility of positioning depending on the stage of the cycle. In support of the roadheader activities, an integrated conveyor system mounted on a sliding floor arrangement is able to be advanced as the mining face progresses. This sliding floor consists of four 1.5 m × 6 m sections that utilise hydraulic rams to ‘walk’ inbye, allowing room for installation of precast concrete floor panels for final floor completion. This method borrows from the tunnelling and construction industries to eliminate place-change delays in the mining cycle by enabling complete ground support installation without retreat of the primary development machine from the face. The aim is to reduce the project duration with the completion of final floor and services to within 30 m of the operating face as it advances.

Mar 21, 2011

By S Ellis, J McMullen, M Habner

A new leaching regime was implemented at Kalgoorlie Consolidated Gold MinesÆ (KCGM) Gidji plant on a cyanide leach of ultra-fine ground sulfide concentrate. High lime concentration and lead nitrate were used to overcome the refractoriness of the fine sulfides (high reactivity of fine sulfides with the presence of gold tellurides). The leach pretreatment stage was shown to be detrimental and was shut down. Lime titration was introduced as part of the process control. It was shown that the leach could be performed at low dissolved oxygen, (ie 3 - 5 ppm) to avoid sulfide oxidation and the associated high cyanide and lime consumption. Plant results showed reduced cyanide consumption (40 per cent) and an accelerated leaching rate, whereby most of the gold was dissolved in 24 hours compared to 72 hours used previously. Similar work was performed at KCGMÆs Fimiston plant, which leached a combined ultra-fine ground sulfide concentrate along with the slimes fraction from hydrocycloning the bulk flotation concentrate. The use of lead nitrate, high lime and carbon-in-leach generated a faster leaching rate and minimised adsorption of gold on fine pyrite particles. The grind, previously controlled with a P80, was replaced by a P98 to give a better operational indication of top size hydrocyclone performance. Before the implementation of the changes, average leach residues for slimes and UFG were respectively 4.0 g/t and 5.5 g/t. With the modifications to the leaching regime, average leach residues were lower by 1.5 - 2.0 g/t. Whilst significant improvements have been demonstrated, further work is progressing at KCGM to further reduce ultra-fine concentrate leach tail grades, and also to improve the understanding of concentrate refractoriness and the factors responsible for differences between laboratory and plant leach results. Estimated profits since the implementation of the new approach are in the range of $A3.5 million per year.

Jan 1, 2005

By H Kim, M J. Sun

In order to reduce carbon emissions from the steelmaking process and achieve carbon neutrality, global steel companies are establishing their own medium to long-term strategies and implementation plans using competitive technological advantages held by each steel company. At this point, Hyundai Steel has formulated a product-oriented carbon-neutral strategy based on innovative processing that makes use of Hyundai Steel’s own strength. Based on our experience in electric arc furnace product manufacturing and blast furnace operation in an integrated steel mill, Hyundai Steel is driving the Hy3 (Hy-cube) project, which involves a unique hybrid production system utilising hydrogen and hydrogen-based renewable energy sources. This initiative aims to achieve carbon-neutral production and eventually specialise in producing premium carbon-neutral automotive parts. The project has originality in that it involves not only designing processes using electric furnaces to produce premium steel products such as car body panels and electrical steel sheets, but also aims to reduce carbon emissions from the process, developing carbon-neutral products based on market demand. To assess the feasibility of the Hy3 project, Hyundai Steel conducted two pilot productions. The first pilot was producing a prototype of lower-arm part using electric arc furnace with three different kinds of raw materials: molten iron, HBI (hot briquetted iron), and scrap. Successful performance evaluation of auto parts with 1 GPa strength was achieved. The second pilot has been focused on tire cord steel, with the first-phase tests yielding a 33 per cent reduction in carbon footprint (CFP). Using the advantages of operating experience in electric arc furnace, Hyundai Steel is preparing for test operations producing various automotive parts using an electric arc furnace (EAF) to advance the Hy3 concept. From a medium to long-term technological development perspective, Hyundai Steel’s blueprint includes producing high-end carbon-neutral steel products using hydrogen-reduced iron as raw material.

Jun 19, 2024

By S D. Fox, P B. Swart

Statistics showing that mine rehabilitation is falling behind rates of disturbance continue to be reported in the media. Unfortunately, most reported statistics do not account for the large growth-cycle that mining in Australia experiences, where there are typically significant new disturbances with large portions of these areas not being available for rehabilitation for a number of years. Many commentators assert that better planning is required to ensure that rehabilitation will be able to achieve a safe, stable, non-polluting landform that meets the agreed post-mining landuse.This paper focusses on the revegetation aspects of mine rehabilitation and in particular the matters that need to be addressed in the planning stage so that revegetation success is ultimately able to be demonstrated to regulators and other stakeholders.CITATION:Fox, S D and Swart, P B, 2018. Planning revegetation for relinquishment, in Proceedings Life-of-Mine 2018, pp 113–115 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By A G. Guinea

Every person in an organisation has what could be called ‘a different take’ on what it means to be a safety leader. The directors will tell you they are ultimately responsible for everyone’s safety and that they can be imprisoned as a consequence of a workplace fatality. Managers, take more of a focused approach and would explain that they are totally responsible for the safety of their teams. And then there are front-line leaders. Those that not only have the responsibility (like directors and managers) but they also have the accountability, and the ability, to influence how safely their teams work. But it is not just physical safety that leaders should be concerned with.

May 5, 2022

By T W. C Stambolie

Coalmines, like any other mine, generally involve the classic three-staged approach to mining studies; namely concept, pre-feasibility study (PFS) and feasibility studies (Cusworth, 2012). Subsequent to these studies, and in instances parallel to these studies, the commitment to an environmental impact statement (EIS) is made in order to secure both state and federal development consent. In recent times, the sentiment to both mining and coal is changing whereby the traditional approaches to mine planning and economic evaluation is complicated by evolving environmental legislation, expectations and time frames. It is all too common to take shortcuts in the development of projects in order to create the perception of cost savings and expediting the delivery timeline. Atkins (2016) points out that: boards of so many small to mid-tier mining companies, and a few majors, focus on relentless project delivery too early in the project process, with so little time and effort applied to risk analysis and option development. Unforeseen risks can cost any timeline or budget far more than the effort required assessing and mitigating these. The ultimate risk to any feasible coal project is that of environmental approval and achieving development consent.CITATION:Stambolie, T W C, 2016. A black canvas – planning a greenfield coalmine in New South Wales, in Proceedings Life-of-Mine 2016 Conference , pp 31–35 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By A Scott

Long before a modern mine commences operations it has already become a wealth of information. After start up, it can generate enormous quantities of data û especially with semi-automated data acquisition by instrumented mine equipment. However, much of this data is of limited use for evaluation of (potential) performance unless it links in some way to the site business model. An underlying reason for this waste of data is that the different cultures, financial, technical, community, environmental, etc not only have many areas of interest but also have very different conceptual models by which they evaluate performance. It is too ambitious to attempt to bring all of these cultures together û in a single step. However, the success of the Mine to MillTM project has demonstrated that substantial operational value can be added by using a more integrated approach to comminution. The next logical step is to integrate measurement and then to track performance from orebody model to saleable product and waste disposal. From resource to product also represents a path from very sparse, highly variable data to much more detailed measurement and more representative sampling. However, in both cases the data collected is strongly focused on the technical requirements û not on the business model. This paper considers how to define at least some of the key decision points in terms of some case studies. Performance data from many areas might be used to derive simple models which can then be used for forecasting and optimisation of planning.

Jan 1, 2002

By P Walton, L W. Armstrong, D P. Blair

Sydney is the capital city of NSW and has a population of approximately four million people. Eighty per cent of the cityÆs water is supplied by Warragamba Dam, which is situated some 75 kilometres south west of the city centre. A risk assessment was carried out on the dam and future predictions of water flows into the catchment area showed that there was a risk of a one in 700-year flood not being contained by the dam. The predicted loss of life and property damage warranted the construction of an auxiliary spillway on the eastern side of the existing dam to cater for any uncontrollable influx of water. A test blasting program was instigated and the blasting parameters were established that would lead to routine production blasting of the sandstone rock making it more cost effective to excavate. Blast induced vibrations were a concern to the owners and the dam wall and ancillary infrastructure was instrumented with sensitive vibration monitoring equipment during the test blasting phase of the operation. Once the blasting parameters were established from the testing program production blasting was carried out on a daily basis to maintain æstockpileÆ of fragmented ground for the excavation equipment. Blast vibration models were developed to predict vibration levels for more sensitive areas of the dam to give the operators more confidence in their operations. The blast induced vibration levels recorded did not cause any structural damage to the dam wall and the waveform frequencies of the blasting operation were much higher than that experienced during a recent earthquake. The integrity of the SCAÆs assets were at no time jeopardised.

Jan 1, 2001

An understanding of the way that solutes are transported in mining or natural environments is essential to the development of sound strategies for managing waste disposal. Research on miscible pollutant movement in unsaturated porous media is carried out both experimentally and numerically. Results of numerical modelling are obtained by solving the groundwater flow equation and the solute transport equation. The finite element method is employed and comparisons between simulation results and experimental data are found in remarkable agreement.

Jan 1, 1995

By S Ravn

Under platform exhaust (UPE) systems are often designed into metro stations as a means of removing heat generated by trains as they come to a halt in the platform. These systems are designed to extract heat from the brakes and brake resistors directly at the source in order to capture as much heat as possible before it can enter the public areas of the station, or contribute to the temperature build-up in the tunnels. Due to space requirements for the associated duct and air handling units, the UPE plays a significant role in the geometric design of the platform and station as a whole.In recent years questions have arisen as to the effectiveness of UPE systems. However, very little data is available for designers to use when making important decisions on the station designs for new metro systems. This is important as significant savings could be achieved by omitting or re-designing these systems for new build stations; not only due to the capital costs of space provision for the duct itself but also due to the associated operation and maintenance cost of the UPE system.This paper will present recent measurements of the UPE system of the Copenhagen metro together with one-dimensional (1D) simulations, looking at typical dispersion of heat into the station plenum box and air exchange through draught relief shafts as the train enters the station in order to evaluate the effectiveness of the UPE system. The aim of this paper is to disseminate the results of measurements and analysis to increase awareness of the issue and to provide discussion relevant to designers in their evaluation of heat removal systems in new build station designs.

Mar 8, 2011

By I R. Souza

At the mining industry, there are several uncertainties that may affect the mobile mining equipment fleet sizing and usage, such as commodity supply and demand, which impacts the mineral price, environmental licenses to allow operations and strategic decisions made by the own mining company. Due to that, it may happen to acquire a mobile mining equipment for a specific site and before it finishes the entire forecasted life cycle, the machine gets idle on that operation and a decision must be made regarding this matter. On large mining companies with several sites, equipment transfer provides a good solution to solve this issue and at the same time it provides operational flexibility and allows to use the equipment until the initially planned working hours. This article presents a method to compare technically and financially whether it’s more feasible to transfer a used equipment or to buy a new one. In other words, we will compare a brand-new machine versus a used one in terms of safety, net present value (NPV) considering both capital expenditures (CAPEX) and operational expenditures (OPEX), technological obsolescence, risks, equipment maintenance reliability and lead times. Although it’s not the main purpose of the paper, it will also be briefly discussed the importance of having a considerable amount of backup equipment to handle low likelihood and high consequence risks that may materialise. This backup equipment portfolio is particularly important to avoid loss of sales and profits in case the production plan changes and it demands further equipment than initially planned to cope with the forecasted production.

Nov 8, 2021

By J Greberg

This paper discusses the use of simulation in the mine planning process. A case study on the Newcrest Cadia East project is presented, and the challenges and possibilities for using simulation as a tool for mine planning and scheduling is discussed.The simulation study presented in this paper was performed during the project’s prefeasibility stage, and focused on the planning and scheduling of the development of panels in the future mine. The Cadia East project will be the largest underground operation in Australia and the first using panel caving. Simulation was used in order to optimise the development of panels; it was mainly used in order to verify the plans for the development process and allocate resources in an optimal way. The work was performed as an iterative process and adjustments to the plans were made according to simulation results. Bottlenecks were identified and different scenarios were tested.The results from the simulation study shows how different operational constraints affect the planned development process and how changes in priorities can be necessary in order to maintain a high development speed. Furthermore the study shows how changes in planned mine layout requires changed strategies, and how this was solved using the simulation tool.In this paper the authors critically discusses the use of simulation in mining operations: what are the limitations and challenges of using simulation as a tool for mine planning and scheduling, what are the benefits, and what do we aim for in the future?

Nov 22, 2011

By J Bolen, I Cameron, M Huerta, M Okrutny, K O’Leary

As greater amounts of fine iron ore concentrates enter the marketplace, new investments in iron ore pelletising capacity are inevitable to deliver these concentrates to steel industry consumers. When investors assess the two well-proven pelletising technologies, the straight grate and grate-kiln, the most appropriate choice may not be immediately evident. Certain technical, market and site-specific factors will favour one technology over the other; investors need to be aware and understand these factors in order to make the best investment decision. Hatch has compared the merits of both technologies regarding plant configuration; type of iron ore processed; energy consumption and flexibility to use a variety of fuels; ability to produce the required pellet quality; required plant capacity and scale; operating and capital costs and environmental performance. A technology assessment checklist that investors should consider when making a new pellet plant investment decision is presented.CITATION:Huerta, M, Bolen, J, Okrutny, M, Cameron, I and O’Leary, K, 2015. Guidelines for selecting pellet plant technology, in Proceedings Iron Ore 2015, pp 45–52 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By P Swart, A Fletcher, P D. Erskine

Glencore Coal Assets Australia (GCAA) operates five coalmines in Queensland and has rehabilitated thousands of hectares of mined land across these sites. Accordingly, GCAA seeks to continually improve rehabilitation outcomes over time and work towards progressive rehabilitation sign-off. The ultimate test of rehabilitation success is the attainment of an agreed land-use target, whether for biodiversity conservation or some type of agricultural production, and the ability of the rehabilitated landscape to resist degradation and retain desired functions (eg biodiversity protection or grazing productivity). However, success must be based on documented evidence that can demonstrate adequate progress towards rehabilitation targets and is assessed at appropriate intervals. To assist this task, a stepwise decision guide for the GCAA monitoring program was developed to ensure consistent monitoring data is collected across the range of sites. This presentation will discuss some of the processes that were followed to allow GCAA to identify appropriate metrics to assess rehabilitation success efficiently over thousands of hectares.CITATION:Erskine, P, Fletcher, A and Swart, P, 2016. Preparing for progressive mine rehabilitation sign-off in Queensland, in Proceedings Life-of-Mine 2016 Conference, pp 148–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By K Brand, M J. Ind, M Rynhoud

Water management at a tailings storage facility (TSF) presents one of the major risks to the safe performance of the facility. International and domestic dam safety guidelines assess a dam’s hazard category based on the consequences of a dam failure and the subsequent downstream damage to the environment and communities.Often a rigorous risk assessment is undertaken during the design stages to identify and control hazards associated with water management through life-of-mine (LOM) phases. However, as experienced during the recent downturn in commodity prices, early closure of a mine can occur rapidly and unexpectedly. Although guidelines such as the Australian National Committee on Large Dams Incorporated (ANCOLD) recommend that one of the key objectives of integrated TSF planning is to ‘plan all phases of a tailing dam’s life to ensure adequate storage capacity including early closure ’ (Australian National Committee on Large Dams Incorporated (ANCOLD), 2012) this is often overlooked by owners who are focused on fulfilling the mine’s potential and early closure is not on their radar.CITATION:Ind, M J, Rynhoud, M and Brand, K, 2016. Life-of-mine spillway strategy – managing risk associated with surface water at a tailings storage facility, in Proceedings Life-of-Mine 2016 Conference, pp 209–211 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

Gold was discovered at Waihi in 1878. In 1987 the modern Martha Mine opened in the middle of the town of Waihi. Newmont Waihi Gold as the current licence holder has been operating the mine since 2000. The current open pit was scheduled to stop production in mid 2006. An underground mine is currently being developed to the east of the town.   In 2001 serious subsidence issues from historical underground mine workings outside the mining licence and the forecast closure of the open pit acted as a catalyst for the development of new communication initiatives.   In this context Newmont Waihi Gold and the Hauraki District Council initiated a community consultation process with the people of Waihi. The Waihi Community Consultation Committee (WCCC) was established in May 2003. After an initial brief to act as a forum for community participation in closure and rehabilitation of the Martha Mine, the group quickly took on a much more proactive role working towards the long-term social, environmental, cultural, economic and spiritual sustainability of Waihi.   In the course of over three years of meetings all groups represented on the committee have presented their views, developed ideas and established an organisational structure to bring those ideas to fruition. The challenge now is to work together to consolidate likely options, seek sources of funding, produce business proposals and implement the plan for the future of Waihi.   This paper backgrounds the experience to date and describes the outcomes of the process. For more detail on process considerations this paper should be read in conjunction with Part C by process facilitators, T Clark and S Stewart. For more detail on progress towards the groupÆs goals and future possibilities, this paper should be read in conjunction with Part B by Vision Waihi Trust CEO, E Morrow.

Jan 1, 2006

By C L. McIntosh

The west coast of New Zealand’s south island is host to a large number of placer goldfields that stretch from the Westport area in the north to Gillespies Beach in the south and inland to the foothills of the Southern Alps. This area is host to a large number of alluvial, glacial and strand line deposits ageing in range from Recent to Tertiary. In recent years exploration models have been developed for off shore placer deposits on the continental shelf.Gold mining on the west coast has exploited placer gold resources from the 1860s to present, and with the recent surge in the gold price the industry is currently undergoing a resurgence. The current increase in mining is dominated by small-scale mechanical operations usually involving one to two people at each site; a few larger operations also exist such as the Grey River Dredge.Mining methods range from using floating bucket dredges to small diggers. Some of the mining technologies used are similar to those employed during the great gold rushes of the 19th century. Exploration and grade control techniques can be very rudimentary often relying on previous sampling programs or wide spaced bulk sample drill holes. Some bulk sample drilling is used on the larger operations as a form of grade control, most of the small operations tend not to use any ore control sampling prior to mining. Extraction techniques relying on simple gravity based designs with riffle tables or spirals are the most commonly used. Environmental standards are very high within New Zealand and require operators to return mined areas to preagreed to landforms. The high rainfall experienced on the west coast causes challenges to operators in regard to water quality. Technical issues combined with often limited capital provide for challenges to the operations.

Aug 22, 2011