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By N Ozawa, R Kaneko, M Arimit

The Mitsubishi Higashitani limestone mine is a ten million tonne per annum operation located near the city of Kitakyushu on JapanÆs western island of Kyushu. Higashitani is one of the largest limestone mines in Japan and accounts for about five per cent of national production. Blasting practices at the Higashitani mine involve the use of bagged ANFO, dynamite primers and non-electric detonators. Regulations in Japan prohibit the use of site mixed bulk explosives. Blast size is usually around 17 000 tonnes with 20 holes in a single row, two or three blasts are fired per day at a powder factor of between 0.25 and 0.32 kg/m3. As part of a program looking at oversize reduction Mitsubishi, Asahi and Orica agreed to conduct a joint project at the Higashitani mine to investigate the relationship between the powder factor and fragmentation. The first stage of the project was to benchmark the current blasting performance. Five blasts were monitored in each of the 210 (hard rock) and 220 (soft rock) areas of the mine. OricaÆs Powersieve« software was used to measure fragmentation and total rock breaker hours were also recorded for each blast. OricaÆs computer blasting simulation model Sabrex« was used to prepare revised blast designs with a higher powder factor and predict their performance. The performance of these blasts was monitored using the same methods.

Jan 1, 2004

By De Jong HJ

During the forthcoming reline of No.3 Blast Furnace at the Newcastle Steelworks of the Broken Hill Proprietary Co. Ltd., facilities for the screening and weighing o' coke will be installed. The equipment is needed to optimise the sizing and the quantity of coke immediately prior to it being charged to the furnace. Up till the time the furnace was blown out in November, 1982, coke was charged to the furnace by volume, ie by skip fulls only. This resulted in variation to the ore/coke ratio charged due to bulk density changes and erratic skip filling levels. This in turn affects the heat balance of the furnace and causes fluctuations in hot metal chemistry and temperature. A coke rate penalty has to be paid also. Coke layer thickness in the furnace burden cannot be controlled closely, resulting in loss of control over gas distribution in the furnace. A grizzly type screen was incorporated in the skip loading chute but this ineffective method left a great amount of fines with the coke being charged to the furnace. Furnace permeability was therefore reduced, particularly in the hearth.

Jan 1, 1984

Depletion of shallow ore reserves is forcing the South African gold mining industry to exploit reefs at ever-increasing depths. By 2010 around 30 per cent of South African gold production probably will come from depths greater than 3 km (Johnson and Schweitzer, 1996). At such depths, virgin stresses will rise significantly, producing complex rock engineering problems (Malan and Basson, 1998). Concern over structural instability at depth has led planners to seek a technology capable of ædetection of geological structures with a displacement of 2 m or greater (or as appropriate to the mining technique) 200 m ahead of mining at an acceptable costÆ. Borehole radar probably is such a technology. Cover holes are drilled routinely ahead of development. The evaluation of its candidacy for a tactical role in ultra-deep gold mining dependsùamong other thingsùupon establishing the electromagnetic characteristics of the environment hosting significant gold reefs. The Ventersdorp Contact Reef (VCR) is one such reef. Recent borehole radar field trials, presented here, suggest that the VCRÆs overburden is a remarkably translucent, clutter-free dielectric with a Q of ~35 and that the VCR itself is the dominant radar reflector.

Jan 1, 2002

Most of the copper deposits in the Lachlan Geosyncline fall within areas having either a common host rock, mineral assemblage, form of ore body or time and method of emplace- ment. On this basis a Cobar-type ore has been recognised in the deposits of the Cobar -- Mt. Hope - Melrose region. The copper ores in the Tottenham-Girilambone area to the east have a different mineral assemblage. In the more rugged Central Highlands nearer the coast copper deposits are generally concentrated either in one of several Ordovician andesite belts, particularly between Wellington and Woodstock, or within Silurian acid volcanics developed in irregular fashion over a considerable portion of this region. In only a few instances is copper known in the granite batholiths which adjoin these volcanic belts. Native copper and magnetite are characteristic of the deposits of the andesite province and it is possible that future mineragraphic studies will indicate significant differences in the base metal sulphides of both the andesitic and the more acid volcanic belts. Ores having similar mineralogy and form to the Captain's Flat deposit are known at various localities in the eastern segment of the latter belt. In the Gundagai area several small copper deposits with associated nickel minerals have been developed in the Coolac Serpentinite belt.

Jan 1, 1969

The first thing to be aware of is that the warming effect of carbon dioxide is strongly logarithmic. Of the 3¦ that carbon dioxide contributes to the greenhouse effect, the first 20 ppm has a greater effect than the following 400 ppm. By the time we get to the current level of 384 ppm, each 100 ppm increment will produce only about 0.1¦ of warming. With atmospheric carbon dioxide rising at about 2 ppm per annum, temperature will rise at 0.1¦ every 50 years for the next couple of hundred years before the effect becomes minuscule. The warming of the 20th century, as the Earth came out of the Little Ice Age, was a consequence of short, high-amplitude solar cycles. A number of solar physicists have predicted that the next solar cycle, Solar Cycle 24, will be quite weak. Based on the correlation between solar activity and the EarthÆs climate, a temperature decline of 2¦C is predicted for the mid-latitude regions over the coming decade, equating to the experience of the Dalton Minimum. Anthropogenic warming due to carbon dioxide will not ameliorate this temperature decline. Increased atmospheric carbon dioxide is wholly beneficial due to itÆs fertilisation effect. Efforts to inhibit Australian carbon dioxide emissions are exactly wrong in science.

Jan 1, 2009

By V S. T Ciminelli

This work aimed at evaluating the acid rock drainage (ARD) potential of five samples of a Brazilian gold sulfide mine in a decommissioning process. Three of the most traditional ARD prediction techniques, Standard Acid Base Accounting (Std ABA), Modified Acid Base Accounting (Modified ABA), as static methods, and humidity cells as a kinetic method were tested. Both the Std ABA and the Modified ABA results indicated an acid generation potential for some of the studied samples. In the other cases the results were inconclusive. The five samples were then submitted to humidity cell tests during 27 to 30 weeks. At the end of the period, the leachate pH was stabilised in a range from 3.4 - 4.1 (four samples) to 5 (one sample). The presence of relatively high levels of sulfate and dissolved metals was detected throughout the operation, specifically, Ni and Zn, and less frequently, As. These findings are discussed with the help of the samples mineralogy and Eh-pH diagrams. The results obtained in this investigation indicated potential environmental risks of this mining area. In this particular case, the kinetic tests were shown to be essential to the identification of the samples ARD potential.

Jan 1, 2003

By P D. Erskine, A Hine

The current Queensland Government’s rehabilitation guidelines for post-mining landforms present a hierarchy of preferred outcomes for different areas within the mine site (see Figure 1). Within all areas, restoration of a ‘natural’ ecosystem is clearly prioritised as the preferred end land use, although it is not a mandatory practice. Beyond the official guidelines, there is also an implied preference for renaturalisation echoed in most environmental impact assessments and closure plans (Lamb, Erskine and Fletcher, 2015). In practice, however, ecosystem restoration does not extend to construction of a realistic topographic form, largely rejecting the ‘natural’ aesthetic implied by ecosystem restoration in favour of adopting a functional aesthetic in deference to standard engineering criteria.This presentation argues that the established disconnection between actual and implied landform aesthetics is indicative of a wider problem around end landform planning. It contends that such disconnects are the result of the impact of competing ‘ways of seeing’ (Bradley and Kearney, 2007) the same landscape, and reflect the struggle between, and inclusion of, these differing perspectives within the planning process itself. We propose that recognition of the complexity of landscape perceptions is key to improving post-mining landscape outcomes, and the misalignment between land use values and landscape aesthetics can be addressed by establishing an overarching framework for landscape preferences. As such, we outline the reality of stakeholder landscape preferences, and present a critical response to current planning practices within the life-of-mine (LOM).CITATION:Hine, A and Erskine, P, 2016. Recognising and integrating stakeholder landform expectations into life-of-mine planning, in Proceedings Life-of-Mine 2016 Conference, pp 154–157 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By M Gao, V Lawson, W Valery

Changes in metal prices and mine output over recent years have required the Copper Concentrator of Mount Isa Mines to operate at annual tonnage rates varying from 4.0 million to 6.5 million tonnes. Several circuit combinations were operated during this period utilising up to two semi-autogenous grinding (SAG) mills and up to two ball mills. The aim was to maximise grinding efficiency and keep unit costs constant regardless of throughput rate. Measures to improve the SAG-ball mill unit operation were implemented with each circuit change. These included installation of a splitter to divert SAG Mill cyclone underflow back to the mill, increase SAG ball charge from four per cent v/v to eight per cent v/v, reduce in SAG top feed size and increase of ball mill grinding medium size. Modelling work and surveys led to a new design of the SAG liner profile from 60 rows of rail bar liners in a high-low arrangement to 40 rows of top hat liners in a high-high arrangement. An on-line SAG Mill feed sizing monitor was recently installed to improve grinding control.

Jan 1, 2000

By H Aoki, A Nakayama, K Morita, S Yamada

The thermal conductivity of mold flux is crucial for optimising the productivity and quality of steels. This study investigates the thermal conductivity of molten oxides, including CaO-BO1.5-AlO1.5 (CBA), CaO-BO1.5-AlO1.5-SiO2 (CBAS), and CaO-MgO-BO1.5-AlO1.5 (CMBA) melts, using a hot wire method. Additionally, their structure is examined using Raman spectrometry and magic angle spinning nuclear magnetic resonance (MAS-NMR) to explore their relationship. Furthermore, first-principles calculations are employed to assess the covalency of each bond in the melts for a more quantitative analysis of their relationship. The study confirms that an increase in the CaO concentration of the CaO-BO1.5-AlO1.5 melts reduces the amount of bridging oxygen and consequently decreases thermal conductivity. The covalency of the B[4]-O bond is highest, especially when the second-nearestneighbour Al atoms transition from Al[6] to Al[4], forming the AlB3O7 structure with B[4]. The relationship between thermal conductivity and the structure of CaO-BO1.5-AlO1.5-SiO2 melts can be quantitatively assessed using the degree of polymerisation of the network structure and the variation of covalency as indicators. Furthermore, replacing CaO with MgO in the CaO-MgO-BO1.5-AlO1.5 melts reveals a mixed alkaline earth effect on thermal conductivity.

Aug 21, 2024

The crushing and concentration of ores, as Herbert Hoover commented in a footnote in De Re Metallica, stretches back at least 6000 years. During those years there have been continuing changes and improvements in mineral processing technology. It has expanded greatly in its ability to handle different types of minerals, and lower grade and more complex ores. Australia will be dependent on the mineral industry for the fore- seeable future and there will be continuing demands on the mill opera- tors to improve the technology with regard to efficiency, flexibility and costs. These demands will be met successfully in the future as they have been in the past. This Mill Operators' Conference is an important forum for assessing our present position and planning for the future.

Jan 1, 1988

By Huajun W, Long LZ

The composition of fly ash and formation mechanism of cennospheres are introduced in this paper. The signification of using this potential new mineral processing resource is emphasised. The beneficiation properties of the components of fly ash, such as susceptibility, specific gravity, size, shape and flotability etc have been examined in detail. A technique was designed to process fly ash from the XiGaoJing power plant in Beijing, and a flowsheet is also presented. Flotabld cennospheres, magnetic beads, sinkable beads, carbon and advanced pozzolamics can be obtained as separate products through this flowsheet. It is emphasised that the beneficiation of fly ash is an efficient means of totally utilising the resource. Examination of the products show that they have good physico-chemical properties. Possible areas of their application are also Suggested.

Jan 1, 1993

Analysis of the 2001 Australian census data set can be used to gain a detailed insight into the trends and levels of employment in different industry sectors. There is a common perception that employment of geoscientists within the mining industry and indeed across all industries has decreased significantly. However, the data shows that the number of individuals stating that they are geoscientists employed across all industries has decreased by only five per cent from 5336 in 1996 to 5067 in 2001. Within the mining industry (Australia and New Zealand Standard Industrial ClassificationÆs û ANZICÆs mining class), the number of geoscientists employed has decreased by ten per cent from 2701 in 1996 to 2441 in 2001. These figures, while showing a decrease, do not reflect the magnitude of the decrease commonly perceived. However, further analysis shows the number of geoscientists employed in mineral exploration may have decreased significantly more.

Jan 1, 2003

South Africa is a semi arid, water scarce country that has undergone recent major political and social transformation. This transformation has ensured that water management has become a primary environmental concern in the South African mining industry, raising the status of water from an ancillary service to a fundamental factor in mine planning. The coal mining industry has been involved in the development of integrated catchment management plans since the late-1980s when a series of initiatives commenced in catchments where collieries operated. The plans focused attention on water supply and water demand management, the equitable access to water supplies, and intersectoral approaches to decision making, before the promulgation of new legislative and policy frameworks. Development of an integrated watershed management plan for the Olifants River basin, located in the Mpumalanga province, commenced in 1990. The Olifants River is an international river basin of 54 570 square kilometres and shared by South Africa and Mozambique. The upper watershed, locally called the Witbank Dam catchment, will be the focus of this paper. It has an area of 3400 square kilometres and is the major coal mining, power generating, and maize-growing region of the country. The processes embodied in the integrated watershed management plan had no formal guidelines but rather developed in an ongoing fashion over time. The plan commenced with a situation analysis involving the major stakeholders that identified principal technical shortfalls. These shortfalls were investigated under the guidance of multisectoral committees. The Olifants River Forum was started to extend awareness of the initiatives on an informal level throughout the whole watershed. The results of the investigations enabled water quality guidelines to be established for the upper catchment. To achieve the guideline levels additional initiatives were developed including a scheme to manage mine water discharges into the river system, the development of a standard four-step water management process, investigation and development of innovative mine water treatment processes, specifically sulfate reduction technologies, the use of gypsiferous mine water for irrigation, river and dam hydrological models, groundwater models and biomonitoring. Significant outcomes from the process have been achieved including the improvement in water quality in the Witbank Dam catchment. Equally significant have been the development of partnerships between businesses and between businesses and the community specifically in the use of mine water for irrigation. The plan realised a number of requirements for success including, the development of trust, openness and transparency with information, the essential need for consultation and negotiation and the involvement of third parties to validate information. The future still holds the potential for disputes between upstream and downstream water users but understanding, transparency and accountability between all players have, and will in future, enable the matching of the increasing demands on a scarce water resource to the needs of all.

Jan 1, 2003

Although technology and circumstances are in a constant state of change, the principles of managing the human element remain constant. The isolated mining community continues to form the backbone of the minerals industry but the nature of the isolation, along with the economic and political environment of the industry, is changing. These changes require new inputs by management to the workforce. Management must determine an effective working relationship with unions on its mine site and concurrently contribute to the build- up of the expertise of the individual worker through training and communication. It must also retain a proper balance, by way of human contribution, in cost and information reporting and in other areas amenable to computerisation. These comprise the aids to management necessary to achieve the desired operating efficiency and profitability.

Jan 1, 1980

I would like to start by thanking The AusIMM and CSIRO for organising this excellent conference and inviting me to give a keynote address. Today I will focus on some broad observations of our industry, and leave the technical discussion to my colleagues who are presenting specific papers covering a wide range of topics. In preparation for this paper, I did a little research into the early history of the Pilbara iron ore industry. I was fascinated to read a quote attributed to Harry P Woodward, the Government Geologist in the late 19th century, before Federation. Mr Woodward described the Pilbara as an iron ore country and observed that æthere is enough to supply the whole world should the present sources be worked outÆ. Mr WoodwardÆs prediction could be viewed as wishful thinking and certainly at Hamersley Iron I would gladly envisage the Pilbara supplying the worldÆs entire iron ore needs! In reality, Western Australia accounted for 162 million tonnes or 36 per cent of seaborne trade in 2001. An impressive effort, but not quite the total world supply as Mr Woodward imagined. But we shouldnÆt dismiss these historical musings out of hand û perhaps we could see it as a challenge for the industry to æwork outÆ the present sources. We all know there is abundant iron ore in the Pilbara, and I expect it is only a matter of time until our collective technical expertise and sheer hard work will enable us to utilise its greater range of ore types. Opening up new markets will be a key pathway to creating additional value from the Pilbara ores. Today I will examine the state of play of our industry and the major influences that shape our business at present, before considering what the future might hold for us. I canÆt guarantee the accuracy of my crystal ball, but the stability and long-term nature of our industry does enable some reasonable hypotheses on where we are heading. I will also spend some time examining the way in which the iron ore producers are working to maximise the value of their resource base and obtain more from their existing capital assets.

Jan 1, 2002

Environmental leaching methods such as the toxicity characteristic leaching procedure (TCLP) test or the ASLP test are used to assess wastes including mining and mineral processing by-products. These tests were initially designed as regulatory tests simulating conditions in a co-disposal municipal landfill waste facility and do not allow leaching performance to be predicted in site specific scenarios. Further, the assumptions underlying these tests tend to define worst-case scenario leaching conditions for by-products from the mineral industry disposed of outside a co-disposal scenario.   Recently some characterisation leaching test methods have been issued as ISO/TS standards (ISO/TS 21268-3:2007 and ISO/TS 21268-4:2007) that aim to define the leaching performance of soil type wastes and to predict the leaching performance of these wastes over long time frames. In this preliminary work these standards are trialled for by-products from the mineral industry and the quality of information that can be obtained from them compared to TCLP/ASLP tests.   Where clear comparisons were possible, the TCLP/ASLP tests were typically found to extract a similar, or often greater, amount of component than (i) tests conducted at the same pH but without the acetate buffer or (ii) for test conditions aimed at simulating long-term leaching in an eluate defined by the waste type. While further work is required, the preliminary results indicated that the tests may provide reliable long-term estimates of leaching performance of wastes in soil types of variable pH and provide a suitable basis for long-term planning for optimal waste handling, treatment or even re-use.

Jun 1, 2010

Natural gas from the south west Queensland gas fields is now available in north west Queensland to fuel the development of many Carpentaria Mineral Province projects. Like these projects, the south west Queensland gas project, developed under the operatorship of Santos Ltd, has its own æMining CycleÆ. While the project is entering its third expansion phase, it is at the same time actively extending its discovery phase, with large programs of gas exploration and reserves definition. This paper outlines the history of the south west Queensland gas project, with particular emphasis on the relationship of the project to north west Queensland.

Jan 1, 1998

ALTHOUGH discovered as long ago as 1817, by Strohmeyer, the use of cadmium did not become in anyway general for nearly a century. Its properties, although well known, did not recommend it to users of metals generally, and it was, on the whole, regarded more in the light of a nuisance to zinc producers than anything else. Its real value was not appreciated until both the United States of America and Germany, who are entirely dependent on outside sources for their supplies of tin, were faced with the unpleasant fact that their tin stocks were being rapidly depleted, with practically no prospect of having them replenished. This resulted in serious efforts being made in the UnIted States of America to conserve what tin was available, and, as a consequence, several metals were tried in the hope that they would prove satisfactory substitutes for tin. Among these was cadmium, and it was found that cadmium could replace tin in a manner sufficiently satisfactory to permit of its use in many directions where tin had been used before.It is on this ability of cadmium to replace tin that its use became in any way general at first; but since then new avenues of development have been opened up in which its physical and chemical properties are proving their value. It is highly probable that its use will extend very considerably as time goes on. OCCURRENCE OF CADMIUM.There are several cadmium minerals known, but none of them occur in profitable quantities as ores. The cadmium of commerce is derived almost entirely from zinc minerals and ores in which it is almost invariably present in proportions which are usually very small. Cadmium behaves metallurgically almost the same as zinc, and hence constitutes a fraction of 1% of almost all spelter.

Jan 1, 1923

The exploration methods used by the British Coal Corporation in 1990 improve the geological reliability of underground coal production. Although some of the techniques in common use have been proved to be effective, their limitations are recognised and concentration has been on the increasing integration of direct and remote sensing techniques. Attention is focussed onto first seam workings in sections of at least 2 metres in the depth range of 400-1200 metres and covers both surface and underground exploration. The case studies of exploration techniques and their effect on mine design at several existing collieries are representative of a wide range of geological environments within the more productive British coalfields. Notwithstanding such improvements in exploration and geological reliability, further new exploration technology is currently being investigated or trialled by British Coal.

Jan 1, 1991

Investment decisions in the Australian mining industry are often made without awareness of the impact of risk on project outcomes. A fundamental change in thinking is required to move away from the traditional attitude of æcushioning the blowÆ towards a measured approach to project risk. Such an approach involves quantifying and understanding project uncertainty so that investments may be shielded from downside risk while at the same time exposed to upside potential. Communication and collaboration between study teams and corporate financial managers must be improved before the industry can improve its project investment record. Monte-Carlo simulation provides a way to quantify and understand investment risk, but its accuracy depends on how well the variability of input parameters is estimated. Research in this area is currently centred on quantifying uncertainty in mineral resource estimation using new conditional simulation techniques, but a less-rigorous method can be applied in practice to begin the education process and develop the required awareness at board level.

Jan 1, 2003