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By R Pax

Feed ore variability, the major disturbance into a mineral processing plant receives considerable attention operationally, and at research and strategic levels to ensure that the throughput of the ore are maintained at all times whilst encouraging a sustainable approach to recovering the valuable minerals from ore bodies. Effort and insights from mineralogical and processing characterisation (eg. ore hardness) of sub-ore body domains allows sequencing for processing to ensure consistency and throughput for the size sensitive grinding unit processes. Optimising the blast fragmentation has benefit as does pre-concentration using ore sorting. Blending of ore domains with different characteristics is common for operations. In recent years a number of technologies have become available for on-line and more rapid assessment of ore and have been discussed in a recent paper by Cameron et.al. (2016) as an opportunity for further utilisation of mine-to-mill (and mine to product) strategies. Current concepts have focused on extensive characterisation of ores so that current control practices can be realised and made more effective with relatively slow measurements and actuation. CITATION: Pax, R, 2018. Dynamic concepts for mine to mill operation and optimisation, in Proceedings Complex Orebodies Conference 2018, pp 124–125 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By D H MACKENZIE

In common with several great orebodies and mineral camps around the world Broken Hill has been the subject of state-of-the-art technical and scientific scrutiny during its long working life. During the early years geological interest in Broken Hill tended to be directed at the body for its intrinsic scientific worth, mainly on account of its large size, high grade and wealth of mineral species. For much of the last 60 years the interest has had a more applied motivation, namely, to assist the search for either repetitions in the Broken Hill field or analogues in other terrains. This paper looks at the major changes in geological concepts and exploration techniques applied at Broken Hill and attempts to assess their impact.

Jan 1, 1992

By X T. Nguyen

Western AustraliaÆs Mining Act 1978 was amended in 2010 to provide for the requirement of a mine closure plan to be submitted to the Department of Mines and Petroleum (DMP) for approval, as part of a mining proposal application. The mine closure plan must be prepared in accordance with approved guidelines. Guidelines for mine closure plans were developed to assist the mining industry in Western Australia to plan and implement effective closure of mines. The guidelines focus on the application of integrated mine closure principles and industry best practice information on mine closure. This, includes stakeholder consultation, risk based approach, data collection and monitoring, development of completion criteria and financial provision.Due to the potential high level of public interest in the guidelines, extensive consultation with stakeholders was conducted. The purpose of this paper is to share experiences from the consultation process.CITATION:Nguyen, X T, 2012. Mine closure guidelines for Western Australia and consultation process, in Proceedings Life-of-Mine 2012 , pp 43-46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By S Hughes

The smelting of concentrates and secondary materials has been subject to increasing challenges in recent years due to declining grades of feed materials, increasing impurity levels and ever more stringent environmental regulations. In addition there has been a growing focus on maximising the efficiency of energy usage and recovery of values. New opportunities have been created with rising metals prices and improved systems for the collection of secondary materials, giving rise to a need for more flexible process solutions.This paper focuses on a number of specific cases where a process solution has been developed using the Outotec« Ausmelt Process to meet particular feed material challenges and overcome limitations inherent when employing traditional pyrometallurgical processes.The first case involves the development and commercial implementation of a smelting process to recover values from zinc smelting residues typically deposited into dams as a waste product. The second case describes the application of the Ausmelt process for the smelting and converting of secondary copper feed materials, including e-waste. These materials contain a wide range of metals and plastics and need to be processed appropriately to maximise the recovery of values whilst avoiding environmental problems. The third case study covers the smelting of nickel concentrates containing elevated magnesia levels as well as nickel bearing catalysts with high alumina content, neither of which can be readily processed when employing traditional pyrometallurgical technologies. CITATION:Hughes, S, 2013. Pyrometallurgical process solutions for complex raw materials, in Proceedings MetPlant 2013 , pp 519-530 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By D Moss, P Ganza

There are continuing developments in underground narrow vein mining, from innovative mining methods using low-profile equipment to adaptations of current mining methods using equipment such as road-headers. The development of new mining methods and mining equipment has one purpose in mind û to extract narrow reef orebodies keeping dilution to a minimum, whilst maximising mining recovery. Achieving this will increase the head grade of the ore mined and reduce the tonnes delivered to the mill. Narrow vein mining in Australia has been limited to traditional hand held or mechanised drill and blast methods using existing æoff the shelfÆ equipment. Numerous trials have been undertaken using rock cutting technology and lower profile equipment, but these mining trials have not resulted in the full implementation of any new mining method or the adoption of low profile equipment in narrow vein mines as an accepted mining methodology. Mine operators in Canada and South Africa have teamed up with a number of equipment manufacturers and have taken steps to further mechanise and automate the mining of narrow vein orebodies, in particular to increase safety and productivity. The challenge to Australian narrow vein mining projects is to capitalise on work undertaken by overseas mining companies and equipment suppliers and to investigate the adaptation of low profile coal mining machinery to specialised metalliferous mining. With the inevitable fall in metal prices, it is necessary for Australian mine owners and mining contractors to apply these specialised methods and equipment to make narrow vein mining profitable.

Jan 1, 2005

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

Flue gases from electrical power station boilers, roasting, metallurgical and chemical plants could be treated by flotation using conventional flotation machines. The flue gases are introduced into the pulp instead of the air. The flotation media is a suspension of Ca(OH)2 or CaCO3 or a solution of NH4OH etc containing Na oleate as collector and frother. The SO2 and dust content of the initial flue gases were experimentally reduced by 100 to 1000 times in one flotation operation. The velocity of the flue gases through flotation machines could reach approximatively 0.4 to 0.5 m/s and more against 1.5 m/s reached in scrubber absorbers used for this purpose, but the quality of purification is expected to be better for flotation, which is essential for the cases of heavy polluted metallurgical and chemical flue gases. For some chemical plants the flue gases flotation media may be different and more suitable as compared to the above mentioned media. The proposed flotation method could be used for separation of dry grinded ores in the form of aerosols, with a realisation of flotation from a closed space (gas bubble in the pulp) onto the interface liquid-air where the particles are attached inside the bubbles.

Jan 1, 1993

In October 1993 it was decided to undertake the fourth phase of mining at Big Bell. This decision followed the exhaustion of open pit reserves in January 1993. Two stages of mining were proposed for the new underground mine. The initial stage would mine the remnant ore, consisting of the rib and crown pillars and lower grade ore on the hangingwall and footwall side of the old open stopes, which were mined from the 1930s to 1950s. Most of the old open stopes were backfilled with either deslimed mill tailings or development mullock, both of which were economic to recover. However, the mineable ore from this resource was difficult to evaluate. The second stage focused on mining ore outside the remnant areas and was initially proposed as a Core and Shell method under a caving hangingwall. This method has since been superseded with sublevel caving, in part due to the very high and deviatoric stress conditions encountered at Big Bell and the relatively long mining cycle required for open stoping. The problems and challenges discussed in this paper will cover the identification of remnant ore reserves, dewatering the old workings, and remnant mining.

Jan 1, 1998

Although laterite ores already provide a significant proportion of the world's nickel and cobalt production it is anticipated that they will surpass sulphide ores as a source of nickel in the next century. The most recent period of greenfield nickel project construction was during the 1970s when it was notable that all of the eight new plants were based on treating laterite ores. This was because of the relatively large selection of available high grade laterite ore deposits amenable to cheap open cast mining and a paucity of high grade sulphide ore prospect alternatives. Of the three processing options for treating laterite ores: 1. smelting for the lower horizon saprolite ore, 2. ammonia; and 3. acid leach for the upper horizon limonite ore, smelting currently accounts for about 80 per cent of nickel production. In the future, as saprolite ore grades decline because of relatively high exploitation rates, the incentive to process the large untapped reserves of limonite ore will increase. The high cobalt content of limonite ore also makes it ideally suited to processing by a hydrometallurgical rather than smelting route. With only two exceptions, all saprolite smelting operations have a Class 2 nickel end product (largely ferronickel) and do not produce a cobalt by-product. As a result of technological advances, the modified ammonia leach process for limonite and transition ore as undertaken at Yabulu, now allows the production of pure nickel metal as a Class 1 product, along with significant tonnages of cobalt by-product. The mixed Ni-Co sulphide intermediate product of the pressure acid leach processing of limonite ore at Mon is converted to Class 1 nickel and cobalt metal at Fort Saskatchewan, Canada.

Jan 1, 1996

By T Seifert, P Krolop, K Niiranen, S Gilbricht

The Per Geijer iron oxide apatite deposits (IOA) display significant potential mineral resources for Luossavaara-Kiirunavaara AB (publ), known as LKAB. LKAB continuously mines magnetite/hematite ores in northern Sweden for almost 130 years. The Per Geijer deposits reveal a high phosphorus content and vary from magnetite-dominated to hematite-dominated ores, respectively. Furthermore, they show a large variation in texture, mineral composition, and relation to wall rocks. The high phosphorus concentration of these ores results from highly elevated content of apatite as gangue mineral. Reliable, robust, and qualitative characterisation of the mineralisation is required as these ores inherit complex mineralogical and textural features. For this purpose, comminution tests at laboratory scale in combination with scanning electron microscopy-mineral liberation analysis (SEMMLA) were carried out. Based on this work, significant information on the modal mineralogy and degree of liberation of minerals of economic interest (eg magnetite, hematite, and apatite) were obtained. Results show that there is a difference in the degree of liberation of magnetite and hematite between ore types. This seems to be dependent both on the size fractions and the dominance of each iron oxide in the individual ore type. The amount of gangue minerals seems to have no significant impact on the degree of liberation after comminution. Apatite is generally best liberated in ore types associated with silicates, regardless of magnetite or hematite dominance. Based on the results of this study it can be inferred that a high degree of liberation of the minerals of economic interest can be achieved. However, results need to be verified with further beneficiation steps such magnetic separation, apatite flotation and possibly reverse silicate flotation.

Nov 8, 2021

Project Hobson involves the replacement of an existing 90-year-old above-ground sewer that crosses Hobson Bay in Auckland, New Zealand, and which is nearing the end of its economic life, with a 3 km long, 3.7 m internal diameter segmentally-lined bored tunnel. The $118 M project will offer several benefits to the owner, Watercare Services Ltd, and the local community:provide capacity to meet projected growth in the region,virtually eliminate wastewater overflows into Hobson Bay and the Waitemata Harbour, andremove an obtrusive visual feature and open up the bay for recreational purposes. The geology in the region is a sedimentary formation, which has been significantly influenced by volcanic activity; 49 volcanoes are present within 20 km of the nearby city centre. The geology along the alignment is dominated by two palaeovalleys which have been infilled with a combination of marine alluvium and volcanic deposits. Watercare Services Limited has elected to manage and share tunnelling risk through, among other key measures, the implementation of a geotechnical baseline report (GBR); one of the first uses of this type of document in Australasia. This paper describes the general principles behind the use of a GBR, the development of the GBR used in Project Hobson and some lessons learnt.

Jan 1, 2008

In this paper, a subtle, but important, difference has been drawn between responsibility and mandate. Responsibility has a connotation of financial involvement assigned to an organ- isation as a result of some action it takes, the ramifications of which can be ascribed directly to the organisation. In contrast mandate relates to the power and authority to act. The paper outlines the role of poli- ticians as community decision-makers and the need for Government policy to be flexible in an advanced industrial society so that decision- making options are kept open for as long as necessary. Further, broad community objectives need to be understood and defined so that plans and policies can be consistent. Co-ordination through communication at all levels, especially at the public administration interfaces and with the private sector,is essential for effective resource allocation and efficient implementation. The paper discusses several aspects of the infrastructure responsibility question and some considerations which might be viewed as important by the community decision-makers in considering what responsibility the "community" should accept in providing infrastructure.

Jan 1, 1974

By P R. Lock

The Silver Swan nickel mine is located at the Black Swan Nickel Project, 53 km north east of Kalgoorlie, Western Australia. The Silver Swan orebody is a massive sulphide nickel deposit dipping 70¦ east with an average in situ grade of 14 per cent. Mining of the massive orebody is by Mechanised Ramp Cut and Fill (MRCF). A mining recovery of 98 per cent and minimising dilution are primary goals in extracting the high-grade ore. Placing a distinguishable marker bed (working platform) on rock fill was identified as a key method to achieving these goals. Gravel from a pit located onsite was considered the most suitable material for the marker beds. Research undertaken to design the marker beds using the gravel revealed conventional methods used in mining would not suffice, but that road stabilisation methods could be a viable alternative. Trials used a road recycler to mix cement and gravel in situ and several test beds were constructed on the surface to determine the final design. The trials attempted to replicate a marker bedÆs life cycle of construction and placement and mucking of ore from the marker bed. Testing the marker bed for strength for use as a working platform was completed using a Clegg Hammer; good correlation to a Clegg Impact Value and the compressive strength of the stabilised gravel was found. This paper describes the use of a road stabilisation machine, tests conducted, monitoring and marker bed design and discusses underground placement of the marker bed and its performance.

Jan 1, 1998

By P Gnnther, A M. van Niekerk

Coal mining operations in the Upper Olifants River Catchment in the Mpumalanga Province of South Africa are challenged with the increasing production of excess mine water that cannot be fully managed by existing practices of pollution control at source, recycling, and reuse on mining sites, storage and limited release to the natural water course. In contrast to this, the Olifants River Catchment is experiencing water stress and insufficient water is available to satisfy all water quantity and quality requirements for future industrial and municipal growth. It is estimated that the catchment has a deficit of 192 million m3 per annum if the reserve water requirements are taken into account. The future increased water requirements can be met by water transferred to the Olifants River Catchment from adjacent catchments. The cost of transferred water is likely to be substantially higher than the current cost of water supplied to local municipalities, commerce and industry. BHP Billiton and Anglo Coal Corporation are working together to jointly implement water management strategies that will contribute to the achievement of in-stream and dam water quality and aquatic objectives for the catchment. Consideration is now being given to the treatment and beneficial use of excess mine water. This will inaugurate a new era for the coal mining industry in South Africa, in which a pollution threat to the water resources in the Upper Olifants River Catchment is converted into a water source for beneficial use. Three potential mine water reclamation and reuse schemes have been identified and this paper details the technical, institutional, legal and financial considerations in the implementation of these schemes.

Jan 1, 2006

By McMahon DW

The major components of a mineral reserve estimate for project development purposes are described with respect to sampling, geology, estimation methods, mining factors, metallurgical factors, environmental factors, financial and other factors. Each of these components impact to varying degrees on the recoverable metal or product of a new mining project. The evaluation of a project is a complex process involving the best the profession can provide in terms of geological understanding, engineering ingenuity, metallurgical skills and financial evaluation.

Jan 1, 1983

By J Purandare, D Murdoch

The goal of the life-of-mine plan is to ensure that while the site is left safe, stable and non-polluting, the landscape is such that optimal use can be made of the site post-mining and closure. However, in the face of evolving shareholder expectations and the current international economic climate, numerous mines are ceasing operations and moving into a care and maintenance phase. These changes bring with them a high degree of community concern, not only about the potential legacy of closed operations, but also those mines that continue to operate.While mines across Australia are committed from the earliest planning stage to develop clearly defined post-mining land use and landform objectives, broader expectations related to these objectives may change and evolve during the life of the operation. This is especially the case where a mining operation has a project approval where the land use objectives are aligned to land capability and land use commensurate to that which occurred premining. CITATION:Murdoch, D and Purandare, J, 2016. Optimising land for beneficial use during and after mining, in Proceedings Life-of-Mine 2016 Conference, pp 166–167 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Best R, Poulos H

This paper discusses the results of an Australian Coal Association Research Program project into the development of a routine analytical design method for roof support in underground mines. Simple design tools have been developed using a combination of elastic solutions, free body diagrams, and pile theory. An approach to the design of roof support in layered strata based on the ability of bolts to resist shear stresses is outlined. It is shown that pre-tensioning and angled installation are effective ways of increasing the effectiveness of bolts in such a situation. In highly stressed strata, macroscopic failure is predicted and a design based on the support of surcharged rock wedges is proposed. The methods are applicable to both coal and metalliferous mines.

Jan 1, 1995

This paper gives the background to the development of solvent extraction processes for the recovery of metals from aqueous solutions. Its growing importance in Australia for the recovery of both uranium and copper is dis- cussed, as well as the developments in mixer-settler design as applied to recent plants. The economic significance of solvent extraction as an alterna- tive to cementation is discussed and important features of each process are highlighted by comparison of costs for each process in a hypothetical situa- Tion.

Jan 1, 1971

By Battino S

ABSTRACT' The high gas emissions associated with coal extraction at some-Australian collieries have provided a need to investigate the methods used to predict these gas levels and the vent- ilation requirements for gas dilution. It is generally accepted that the introduction of longwall extraction in particular is associated with complex ventilation planning problems. These problems are made much more severe when the colliery introducing longwalls is already facing high gas emissions even during the development stages. A forecast of likely gas emissions during the longwall mining process indicated possible ventilation problems in maintaining the necessary ventilation levels to satisfy the statutory gas limitations for various production rates. Although there are sound principles used in world recognised methods of gas emission prediction a new approach developed from the findings of the Barbara Experimental Mine in Poland appears most suitable for Australian conditions. This has been applied to an Australian colliery preparing for longwall mining using statistical methods for air

Jan 1, 1983

By J Walasiak

In the climate planning of mines and tunnelling with anticipated poor climatic conditions, and especially in case of longer working shifts, the main question is whether it can be reliably prevented that certain climatic limits laid down be exceeded. Working at high temperature and/or humidity can lead to reduced human working energy û a very important economic aspect û and to a risky lack of concentration on the part of the miners or to heat collapse and extremely dangerous heat stroke. With the Deutsche Montan Technologie GmbH (DMT) climate prediction programs, both the dry and the extremely significant humid heat transfer can be calculated. This is due to the high planning reliability involved. With the help of these climate prediction programs it is already possible to determine the anticipated climatic values for the operation phase as early as the planning stage of new ore or coal fields or of tunnel construction projects and to design the optimum air cooling system for every underground project with due regard to technical and economic aspects.

Jan 1, 2005