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By K Uchino, M Inoue

Self-potential anomalies are generated by fluid pressure gradient, by temperature gradient or by chemical gradient. On the basis of this principle, a new technique is proposed to locate the fire source of spontaneous combustion of coal by the self-potential method. In order to investigate whether this method can be applied to locate the spontaneous combustion of coal in practice, surveys of self-potential distributions were undertaken in a coal waste pile undergoing spontaneous combustion. The results showed that there is a negative centre of the electrical potential distribution in the measurement area. The potential in this centre is about 140 mV lower than that in the surrounding area. Moreover, the negative centre of electrical potential distribution almost overlaps with the high temperature zone. Therefore, it is concluded that it is possible to locate the heat source by the measurement of self-potential distribution.

Jan 1, 2005

WaihiÆs Cornish Pumphouse is located on the edge of town in a dynamic and changeable area where history affects the future. As in any successful project, ingenuity and team work have been significant factors in the planning and implementation of the buildingÆs relocation.   Work around the Pumphouse site commenced circa 1900 with preparation to sink the No 5 shaft. Construction of the pumphouse and the steam driven C pump was completed by 1904 with hints of what was to come evident in 1905 as the No5 Shaft collar had sunk 350mm in four years. By 1907 surface cracking developed over the Milking Cow cave area and in 1913 200 mm was cut off the main pumping rod as the ground was sinking at a rate of 25 mm per year.   In 1913 ground around No 6 shaft had subsided 600 mm.It was also the end of an era as steam gave way to hydroelectricity and electric pumps replaced the C Pump. C Pump was maintained as a backup from 1913 to 1929 and then finally scrapped. 25 years of underground caving operations removed approximately 400 000 cubic metres of ore leaving a 7 ha collapse crater that eventually became known as the mine lake.   On the edge of town a tension zone over the Royal Lode began to develop 50 m diameter chimney collapses as large scale blocks relaxed into unfilled stopes in the old Martha underground mine. After the 1999 collapse part of the main street was closed and after the 2001 collapse Hazard Zones were declared, more streets closed and areas evacuated and retired from residential use.   By 1984 the Pumphouse has approximately one degree of tilt and in 2002 tilt on the Pumphouse accelerated briefly and then settled down. Tilt accelerated again late in 2004 and a scoping study was initiated to define protection options for the pumphouse. The Martha Mining Licence requires Newmont to 'Take whatever precautions are necessary to protect the old Cornish Pumphouse adjacent to No5 shaft' and viable solutions needed to found.   Any work on the Pumphouse comes standard with a wide range of stakeholders, governing agencies and legal framework to consider. Land Information New Zealand (LINZ) is owner and administrator of the pumphouse.

Jan 1, 2006

By Z Fu, E Topal, O Erten

"Mine waste rock management involving waste rock movement and placement, is a critical aspect in the planning of open pit mining operations, as the waste rock haulage cost can be the largest portion of the mine operating cost. The concept of sustainable development in the mining industry also encourages environmentally friendly waste dumps that have zero hazards to people and the surrounding environment. Therefore, a detailed waste management schedule must satisfy economic and environmental considerations. However, the available tools in the market cannot provide optimal waste dumping schedules to meet all these constraints. This paper introduces a user-friendly and automatic tool to optimise the waste dumping schedule, which minimises the haulage cost, and covers the encapsulation of reactive materials to minimise acid mine drainage problems. This tool has been developed by using a new mixed integer programming (MIP) mathematical model that considers both single-lift and multilift dumping scenarios. The application of the proposed tool on a data set collected from a gold mine shows that the multilift dumping scenario has provided a more flexible and economical waste dumping schedule than the single-lift scenario, and both scenarios satisfy environmental requirements.Citation:Fu, Z, Topal, E and Erten, O, 2016. A Modified Software Tool for Mine Waste Rock Dump Planning, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 229–242 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

Societal influences, needs, and uses for recyclable materials are becoming increasingly important business and economic factors in the traditional natural resource companies. Several metals (such as steel, aluminium, zinc, lead and cadmium) are amenable ro recycle which eliminates solid waste generation and decreases the depletion of natural resources. In recent years, the non-ferrous industries have begun to recycle more materials and the next decade will see even larger recycle efforts. In addition to the traditonal recyclable materials, existing metallurgical plants are, or should be, able to handle and recycle materials viewed as 'hazardous'. Unfortunately, some national and regional regulations hinder, and in some cases prevent, the recycling of certain materials. Zinc Corporation of America (ZCA) is currently the largest producer of zinc metal in the USA and one of the world's largest producers of value-added zinc products. Over the last few years, ZCA has become one of the world's largest recyclers of zinc from various diverse materials. ZCA considers these recyclable materials as valuable 'land mines' that provide economic alternatives to the depletion of natural resources while serving society in the minimisation of solid waste disposal. Using the current production facilities of ZCA as a model, this paper overviews the recycling of zinc-bearing materials with special emphasis on: 1. the amenability for recycle within ZCA's pyrometallurgical and hydrometallurgical operations, 2. the quantities and economics of recycle, 3. the problems of recycling hindered by current national and regional regulations, 4. the concepts of total recycle rather than just recovering zinc while generating a modified solid waste, and 5. the motivators for recycling.

Jan 1, 1993

By A Annor, L J. Chen

The production of paste backfill has typically been accomplished through the adaptation of existing technology. Thickeners and disc filters have several drawbacks when applied to production of tailings paste backfill. Personnel at CANMETÆs backfill research laboratory in Sudbury, Ontario, Canada have been carrying out research into and development of methods to produce paste backfill using total mill tailings since 1991. Using a silo for production of paste is not a new concept but has been refined to a marketable level. This technology is based on a fluidization principle that assists in settling the tailings to an homogenous state in a silo. Other developments include patented de-watering technology for use in the silo to speed the settling of the solids to a suitable solids content, optimisation of silo geometry, and instrumentation related to paste backfill production and transportation. The advantages to fluidisation technology are in reduced capital cost, reduced operating costs and in the environmental benefits of using full plant tailings over classified tailings or alluvial aggregates. Another major advantage is in the ability of this technology to be retrofitted to existing hydraulic backfill plants to further reduce capital cost. This paper details the development of the new technology as well as the associated cost savings over other technologies. It will also look at the research and development of unique components that make this technology work.

Jan 1, 1998

By X Yu, Y Shen

The iron ore products should be assessed in terms of in-furnace behaviour and overall furnace performance, their operation should also be optimised under industry-scale blast furnace (BF) conditions, in order to be sustainable and competitive, especially in the context of decarbonisation efforts in ironmaking. While lab and pilot-scale experiments can provide useful kinetics, they are expensive and risky and cannot replicate industry-scale blast furnace conditions for proper assessment and optimisation. In this paper, we review our recent progress at Shen Lab of UNSW in using state-of-the-art Computational Fluid Dynamics (CFD) models to assess iron ore products and examine the effects of their operations on BF behaviour in basic terms, including in-furnace phenomena (flow field, temperature field, species distribution fields etc) and overall BF performance (coke rate, reduction efficiency and top gas temperature etc). We have developed state-of-the-edge CFD models for different purposes, ranging from the static-state BF model featuring unique layered burden structures for offline assessment and optimisation knowledge building-up for iron ore products, to the transient-state BF model for online assessment and optimisation of iron ore productions by describing the transient behaviours of iron ore productions under industry-scale conditions. First, we have studied several iron ore products including the iron ore products used in the present BFs and emerging iron ore products like carbon composite briquette and iron-coke. Second, several iron ore operations are studied including optimisation of conventional burden operations like oxygen enrichment, batch weight tuning and new operations like coke central charging and hydrogen injection in BFs. Third, some time-sensitive operations are also investigated including the use of wet burden materials and the drop in blast temperature on BF performance. These CFD models offer cost-effective research tools for understanding the effect of iron ore products on BF performance and serve as a reliable marketing tool for existing and emerging iron ore products under a wide range of BF conditions.

Sep 18, 2023

By C Bonini, A Markham, P Whittle, B Pearson

"Mine-derived sedimentation in rivers can have significant impacts on the processes and features of the receiving environment and impact on communities reliant on this environment. However, identifying and quantifying the contribution of mine-derived sediment to the receiving environment can be complex. This is particularly the case in remote environments and where little/no baseline assessments have been undertaken. One approach that can be used involves sediment fingerprinting, whereby a unique tracer is identified within the mine-derived sediment to discriminate between mine- and non-mine derived sediment sources downstream. The technique typically involves sampling of sediment at upstream, control and impact sites and sites within the mine deposit. Laboratory analyses are run on all the samples to determine whether the chemical signature (eg presence/concentration of specific metals) differs between each group of samples. In complex environments where the mine-derived signature may be difficult to detect from a basic review of the data, or where sampling constraints may limit the number of samples for analyses, statistical methods can be used to help identify sediment groups. This paper provides a mine case study to show how such an assessment can be undertaken despite the logistical challenges faced while working in remote environments.CITATION:Pearson, B, Markham, A, Bonini, C and Whittle, P, 2013. Fingerprinting and signatures - tracing mine impacts in complex aquatic systems, in Proceedings Water in Mining 2013, pp 287-292 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By M Scoble, E Rubio

The re-engineering of manufacturing production systems has demonstrated the benefits from using production information for optimising processes. This paper explores the techniques and issues in the acquisition and analysis of mine production data for tactical decision making in production control. The use of information and operations management tools is presented in the context of block caving studies, with particular focus on the relationship between secondary breaking and LHD production performance.

Jan 1, 2000

By G C. Reed, J M. Murray

During more than 100 years continuous mining of the lead-zinc orebody at Broken Hill, an immense amount of geological data has been collected about shear zones related to the orebody. The challenge to current mine geologists is to synthesise and interpret these data sets in a way that is applicable to production demands. Precise knowledge of the locations of major shear zones is important not only for the determination of ground conditions but also to develop an understanding of ore remobilisation along these structures. Traditionally, geological information has been collected from drill core and back and wall mapping underground, and interpreted on sections that are approximately 20 m apart. The recent introduction of MaptekÆs Vulcan software has enabled the shear zones to be modelled in three dimensions. The new three-dimensional shear models have been combined with seismic data from the Southern Cross area. The seismic data is collected from a microseismic monitoring system installed in the Pasminco Southern Operations in August 1996 (Rauert and Tully, 1998). The addition of seismic information to the shear zone models has led to a greater degree of certainty about the shear zone locations and has provided information about shear zones in areas yet to be drilled.

Jan 1, 2000

By P Jonsén, S Larsson, M Parian, B I. Pålsson

The question of effective energy utilisation in grinding mills is not new. There are several conflicting arguments about tumbling mills, whether the efficiency is around 1 per cent or maybe 10 per cent, or even much lower. The energy not used is assumed to be lost as heating of the pulp, the grinding mill body, the charge, generation of shock waves and vibrations, etc. Stirred media mills on the other hand are generally considered to have better energy utilisation, but their energy efficiency is still not that clear. To shed some light on this a pilot-scale, wet stirred media mill was investigated over a range of operating conditions. The wet stirred media mill is a Drais PMH 5 TEX pearl mill fitted with an electric motor at 11 kW. It has been investigated over a range of operating conditions to try to balance the dissemination of the input energy in forms of the net grinding energy, mechanical energy losses, and the heating transferred to the pulp, the mill, the charge, and the cooling water. It is found that approximately 20–40 per cent of the input energy accounts for the grinding process. Also, that the difference between gross and net input electrical energy is mainly disseminated as heating of the pulp and cooling water. Mechanical energy losses appear to be much smaller than the heating effects. The use of a dispersant seems to mainly influence the heating effect.

Aug 24, 2022

In this year marking the centennial of the Geological survey of Western Australia, it is appropriate that we should review the value of the contribution of the Survey, and Australian Geological Surveys in general, to the exploration industry. Most geological surveys in Europe and North America had their origins in the first half of the 19th Century when the burgeoning Industrial Revolution was demanding the identification of new sources of coal and iron ore. Australia, as a young nation, essentially dependent on an agricultural and pastoral industry, and with already discovered vast coal resources in Eastern Australia, had, no great need to explore for new mineral resources. However, with the discovery of gold in 1851, the mineral potential of the country became apparent to the whole world and the first Geological Survey in Australia was set up in 1852 in Victoria under A.R.C. Selwyn. After a number of false starts all Australian States had an established Geological Survey by 1900. It is hard to assess the contemporary value of the early work of the Geological Surveys with respect to exploration, almost all major mineral discoveries were made by prospectors and most mining companies had little time for geologists - although the Chamber of Mines in Western Australia in 1910, did recommend that the Geological survey be granted an additional ten thousand pounds over two years to map all existing goldfields and the country between them, and produce a reconnaissance map of the area east of a line between Wiluna and Edjudina as far as the South Australian border!

Jan 1, 1988

By Whittle J

Definition of the optimum open pit, whether an intermediate phase or final design, will be sensitive to many factors. The most basic will include geological and mining constraints, mining and processing costs, pit slopes and product prices. The application of the three dimensional Lerchs-Grossmann pit optimization procedure to this task is described for a range of gold deposits. A new approach to the modelling and manipulation of the geological model enables complex geological environments to be assessed, and sensitivity analyses to be developed. Comparisons with manually developed pit designs have been made to validate the results. The computer implementation is simple to use and can be adapted by non-computer professionals at mine Sites.

Jan 1, 1986

In the search for significant new economic base-metal resources within Australia during the early 1970s BHP's Exploration Department had observed that the majority of lead and zinc con- centrate production in Europe and the USA came from carbonate- hosted Mississippi-Valley-type (MVT) zinc-lead deposits, but Aus- tralia had no history of production from this class of deposit despite several very favourable geological environments, par- ticularly in the large Palaeozoic sedimentary basins. An exploration-research team was established in 1975 and the Lennard Shelf region, near Fitzroy Crossing, was selected as a most promising geological environment. Previous exploration for this class of deposit by other companies in Australia had largely used conventional exploration philosophies (geological mapping, geophysics and geochemistry to identify specific drill targets) but BHP sought specialist advice from a North American expert and adopted a grid-drilling philosophy, which involved wide spaced relatively deep diamond drill holes on a regular grid pattern, and statistical evaluation of the results. This technique resulted in the discovery of the Blendevale Deposit in 1978 in an area which had previously been explored by other companies using conventional methodologies. The deposit was delineated and a pre-feasibility study carried out in 1985 indicated that the resource of 20 Mt @ 8.3% Zn, 2.5% Pb was a marginal proposition.

Jan 1, 1988

This paper discusses equipment replacement strategies and specifically addresses the upgrading of technologically superseded equipment. The process of equipment replacement evaluations is reviewed, and areas have been highlighted where currently accepted practice results in a bias towards retaining existing equipment longer than otherwise justified. The Discounted Average Cost Method is described and the advantages of the technique for this style of decision making discussed. Several key issues influencing the replacement evaluation are also presented together with examples from recent consulting work.

Jan 1, 1992

Australia is presently the world's principal producer of rutile and zircon, and also provides a major share of the world's ilmenite. Since 1980, Australia's share of the world's output of these minerals has fallen. Exhaustion of known resources, together with the changing composition of new deposits, is expected to result in Australia's share of the rutile and zircon output continuing to decline. Its role as a major supplier of upgraded ilmenite, that is synthetic rutile, is expected to increase. In 1994, the Bureau of Resource Sciences assessed Australia's demonstrated resources of mineral sands as follows: rutile 14.4 Mt, ilmenite 132.5 Mt, and zircon 21.0 Mt. These resources are located along the coast of Queensland and New South Wales, in the Murray Basin of New South Wales and Victoria, in the southwest corner of Western Australia, and in the Eneabba region, north of Perth. However, some 45 per cent of rutile and zircon resources along the coast of Queensland and New South Wales are not available for mining because of environmental concerns. World demonstrated resources are estimated at 40 Mt (contained TiO2) for rutile, 50 Mt for zircon and approximately 312 Mt (contained T1O2) for ilmenite. Outside of Australia, the most important resources of rutile, ilmenite and zircon are in South Africa (rutile, zircon , and ilmenite in the form of titania slag), Sierra Leone (rutile), India (ilmenite, zircon and rutile), and Canada (hard rock ilmenite). Significant resources of ilmenite occur in Madagascar and Mozambique.

Jan 1, 1996

By M Ahmed

Reliable face support pressure is necessary for shield driven tunnels in cohesionless soils to prevent excessive ground movements. This paper presents experimental work on stability of a tunnel face using transparent soil models aiming to obtain magnitude of tunnel face minimum supporting pressure, failure pattern and extension of failed zone. A model tunnel was preinstalled in transparent soil which was supported at the face by means of water pressure. Tests were performed by reducing supporting pressure until collapse occurred. Model tests were sliced optically with laser sheet and images were captured for every decrement in tunnel supporting pressure. Later, these images were analysed by digital image correlation (DIC) and vector fi elds of incremental displacements were obtained. Values of minimum support pressures were given for different cover/diameter (C/D) ratios. Geometry of the failure zones depicted for different (C/D) values and appeared to be of chimney shape with a limited extension front of the face. A minimum support pressure was achieved with support pressures as low as 10 ± 1 per cent of the effective vertical stress at the tunnel axis. The stability of the tunnel face was related to the coefficient of active earth pressure with C/D ratio having a small effect on the magnitude of required pressure at collapse. In general, results of the study were in agreement with current knowledge of full-scale situations.

Mar 8, 2011

This paper deals with the evolution of Canadian shaft sinking technology over the last 15 years. Most, if not all, shaft excavation projects in Canada prior to 1990 were sunk using traditional benching methods with labour intensive equipment. In the late-1980s, J S Redpath Limited of North Bay, Ontario, Canada, were contracted to deepen the shaft at Atomic Energy of Canada LimitedÆs Underground Research Laboratory (URL) located in southern Manitoba. The laboratoryÆs role was underground hydrological and geomechanical research, so the project offered both time and opportunity to conduct additional experiments while sinking. The offshoot of the research program was the true birth of the Canadian version of full-face, long round shaft sinking technology. Throughout the 1990s, this sinking method has been further refined over a number of shafts. The results have been faster sinking rates, a safer work environment and an overall improvement in project economics.

Jan 1, 2002

The refractory industry in New Zealand is small, consisting of two main manufacturers - one at Huntly and the other at Kamo. Together these would have an annual refractory production of about 30 000 tonnes. The industries which use refractories include two steelworks, NewZealand Steel Limited and Pacific Steel Limited, the former is involved in continuous casting from sponge, iron and scrap steel and the latter is involved in ingot teaming from scrap steel and steel billets; One aluminium smelter, cement works, dairy companies, small foundries producing engineering requirements and many other small users. The New Zealand manufacturers produce refractories in thefire brick range, that is up to 50 per cent alumina content (ignited basis), based on indigenous raw materials and in the high alumina range up to 85 per cent alumina content (ignited basis) based on imported bauxites. All of the basic refractories high purity silica and high alumina low alkali refractories and many of the higher grade acid resisting refractories are imported.

Jan 1, 1976

By Kentwell D. J, Cusak C. J, Harvey-Kelly F. E L, M D. Goodz

The Morning Star Gold Mine presents an example of a prolific operation with considerable historical records, mine workings, drill hole logs and countless plans from greater than 20 adjacent mines which have now been consolidated to form the current project. Implementation of 3D computer modelling in the planning stages has provided an additional tool to integrate and refine geological models as a guide to some exploration strategies. It has allowed for a re- interpretation of the host rock units, dimensional constraints, new exploration extensions and provisional resource modelling. The initial consideration of this project was to integrate 135 years of mining history into a single database. Each historic mining area had an unrelated mine grid, often established parallel to the long axis of their main stopes; some were based on magnetic or true north. Survey plans were in chain, imperial or metric units. Through the manipulation and rotation of old grids, previously unrelated mine workings began to form continuous mineralised zones, with unmined portions still remaining in between the existing development. Furthermore the current drillhole database of >433 holes showed numerous confirmatory intersections of new mineralisation. A series of tiered tables were created within a relational database to derive guidelines for assessing data to attribute a Mineral Prospectivity Value [MPV] based on key indicators of mineralisation. Indicator logging now forms the basis of geological descriptions.

Jan 1, 1997

The purpose of this paper is to look at the costs of tailings disposal, and in particular the comparative costs of different disposal methods in different situations. Costs are often the hidden design parameter. We know that they are important but sometimes feel that it is not very respectable to talk about them in public. It is better from a public relations point of view for it to appear that the decision-making process is driven by environmental factors or best practice rather than looking for the cheapest option. But this presumes that the two are mutually exclusive and this need not be so. These issues are discussed later in the paper. It is also commonplace for the scale of the mining operation to change with time, typically involving increased throughput rates and total tonnage. New ideas in tailings disposal make their appearance. The regulatory attitude can change. Having made a decision about the disposal method at the time of original feasibility study and design it is easy to suppose that the mine is æstuck with itÆ. But that also need not necessarily be so. Careful costing of options may reveal that a switch in method could be cheaper in the long run. The designer will often tend to think in terms of initial earthworks and site development costs. Aspects of power consumption, labour, and periodic campaigns to move tailings pipelines and carry out embankment raises are either overlooked or not given the same emphasis. This can distort the evaluation process. It is productive to think in terms of dollars or cents per tonne as a basis of comparison, not just the total sums. Tailings disposal can cost from as little as 10 - 20 ó/t to over $1.00/t which is a big range. There may be good and unavoidable reasons for the high figure but there would need to be to justify being so far over the industry average. At the same time, mining and processing costs, at least for gold, are around $15 - 20/t. Viewed from this perspective tailings disposal will always be a relatively small component of the annual budget.

Jan 1, 2000