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The 115-year history of the Hall-Heroult process for production of aluminium has been characterised by a sustained technology-driven improvement in costs and productivity. In the past decade the industry has effectively transferred best practice into older technology with improvements through computer control of the process, and redesign of cell linings using computer modelling . Incremental development is now at the point where diminishing returns will apply for further technical improvement effort however, until the gap between technical limits and current best practice is addressed through major process redesign. The process remains a long way short of its technical limits in energy consumption, carbon anode consumption, cell life and product purity. Investment cost in new capacity is very high, supporting the retention of older and less efficient technology and hence limiting the application of best practice in environmental performance and occupational health exposure. The industry is a major emitter of greenhouse gases yet the process has the potential to release oxygen as the primary waste. All of the above issues will be addressed in the new century, but only through commitment to the necessary long-term research and development that is required to achieve a redesign of the process.

Jan 1, 2000

By J Addai-Mensah, W Skinner, C Kelsey, J R. Kelly, E Baawuah

Comminution continues to be the most capital-intensive unit operation in mineral processing. The fundamental purpose of comminution is to liberate the valuable minerals so that they can be economically concentrated into saleable products. Declining ore quality characterised by lower grade and increased complexity requires significant energy consumption for comminution. Low-grade magnetite ores are typically fine-grained and require fine to ultra-fine grinding (P80 ~ 30 - 40 µm) to enhance its liberation from the typically siliceous gangue matrix. Historically, this has been achieved using multi-stage crushing and grinding technologies, which require high energy consumption with low energy efficiency. This motivated innovations in energy efficient technologies for comminution. Such technology has been developed in the IMPTEC super-fine crusher. It is an innovative, dry (with the potential to be operated wet), media-free, energy efficient crusher that can to reduce 10 mm feed particles to 19 – 30 µm with very low recycle loads. In this study, the mineralogical and physicochemical characteristics of crushed magnetite ore using the IMPTEC super-fine crusher have been investigated in comparison with those of rod milling. The super-fine crusher generated higher liberated magnetite minerals in the – 300 + 212 µm and < 45 µm size fractions compared to rod mill. Both comminution devices generated large low-grade hematite and goethite middlings. However, the rod mill produced higher locked/unliberated hematite and goethite compared to that of the super-fine crusher. Quartz mineral had the highest liberation irrespective of the comminution device used. The super-fine crusher generated higher entrapment of other minerals within the silica matrix compared to the rod mill. The breakage mechanism of the super-fine crusher which is predominantly through high compression with shear, generated improved mineral liberation in the coarse size fractions compared to the predominant abrasion and attrition breakage mechanisms of rod milling. The higher mineral liberation generated by the rod mill is potentially due to the prolonged batch milling of the ore compared to the single-pass open circuit of the super-fine crusher.CITATION:Baawuah, E, Kelsey, C, Kelly, J R, Addai-Mensah, J and Skinner, W, 2018. Mineral liberation studies of IMPTEC super-fine crusher – 130 crushed product, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 313–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By R Miller, D Hawcroft

The business environment is never still and there has been enormous change in demand, technology and opportunity during the last decade. In order to succeed it is necessary for organisations to change the way work is planned, scheduled and carried out. This is necessary just to survive over time. The success or failure of the business is strongly influenced by people; the way they work, the way they are guided and their feelings about being part of both a team, as well as an organisation. Our Sustainable Integrated Management System (SIMS) philosophy is built on the belief that people want to be constructive and creative and it is their environment and working relationships that influence how their energies are directed.

Jan 1, 2000

By A Audétat, W T. Li

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Middle and Lower Yangtze River metallogenic belt is one of the most important polymetallic resource areas in China. Iron oxide-apatite deposits, mainly distributed in Ningwu and Luzong volcanic basins, are a distinct type of iron deposits in this region. These deposits have a close temporal and spatial relationship with Mesozoic dioritic porphyries and are characterised by magnetite-apatite-pyroxene/actinolite ± anhydrite assemblage and large-scale sodic-calcic alteration.Widespread multiphase inclusions in pre- to main-mineralisation stage pyroxene and garnet in Meishan (in the Ningwu basin), Luohe and Nihe (both in the Luzong basin) iron deposits were trapped at ~780°C in extremely saline brines (~90 wt per cent NaCl equivalent), consisting of Na (13–24 wt per cent), K (7–11 wt per cent), Ca (~7 wt per cent), Fe (~2 wt per cent), Cl (19–47 wt per cent) and SO4 (3–39 wt per cent), based on petrologic, microthermometric, Raman spectroscopic studies and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of natural fluid inclusions and synthetic analogues. The high Cl/Br, Na/B and S/B ratios in brine inclusions and the heavy sulfur isotopic values of anhydrite and pyrite (d34SAnh = +15.2 to +16.9‰, d34SPy = +4.6 to +12.1‰) suggest a significant contribution from both halite- and anhydrite-bearing sedimentary rocks. The involvement of evaporites caused the production of large amounts of high-salinity brines with apparently enhanced capacity to extract iron from the dioritic intrusions.According to their geologic features and the above characteristics, these iron oxide-apatite deposits are considered to be a special type of iron oxide copper gold (IOCG) deposits characterised by high contents of Na, Ca, Cl and SO4 in the ore-forming fluids. Moreover, we believe that evaporite-bearing sedimentary basins are more prospective than evaporite-free ones for these kinds of deposits.CITATION:Li, W T, Audétat, A and Zhang, J, 2015. The connection between evaporites and iron oxide-apatite deposits, Yangtze River, China – laser ablation inductively coupled plasma mass spectrometry analysis of Na, S, Cl and Br in fluid inclusions, in Proceedings PACRIM 2015 Congress, pp 623–630 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By T E. Hayward, D H. English, S J. Smith

Gold mineralisation at Bendigo is exclusively associated with quartz reefs, commonly found within or near anticlinal fold hinges. The gold is typically coarse grained (0.5 mm to 5 mm), free milling and displays a complex, nuggetty distribution within the veins. This ore is highly amenable to gravity recovery processes. As the Bendigo operation is not permitted to treat whole ore by a cyanide leach/CIL circuit, the flow sheet is more complex than conventional gold recovery circuits. Primary gold recovery is from a gravity circuit closing the grinding circuit to a bulk gravity concentrate and from a flotation circuit treating cyclone overflow to a bulk float concentrate. The plant capacity is relatively low by current gold industry standards at 600 000 tpa. Re-establishing gold production at Bendigo has presented several challenging, and sometimes competing, issues in process design and operation. The mine, process plant, associated services and infrastructure are at Kangaroo Flat, a low density, semi-rural zone in the southern urbanisation of the Bendigo metropolitan area. One of the main processing challenges during the design was the competing comminution requirement to avoid over-grinding, which would flatten or smear the characteristic nugget gold and hinder effective gravity gold recovery, whilst also providing sufficiently well liberated particles that would respond well to flotation. Important, non-metallurgical challenges were to minimise impacts on the local community from noise, dust, air emissions, visual impact, water egress and off-site traffic.

Jan 1, 2007

Jan 1, 2004

The New Zealand Minerals Industry is small but growing. Over the next 10 years it will be facing stiff international competition for skills to support this growth, particularly from Australia who are forecasting that a further 70 000 people will be employed by 2015.   The value of commodities mined and quarried in NZ continues to increase; and the value of coal, metals and industrial minerals production reached $1.505 billion in 2006, an increase of 15 per cent on 2005. Production increases will continue à. Latest Crown Minerals statistics show that national prospecting and exploration expenditure rose to $29.9 million in the year ended March 31 2006 û an increase of 46 per cent from the $20.4 million spent in the March 2005 year. The equivalent 2001 year expenditure was only $2.48 million.   The industry already experiences difficulty in recruiting the people it needs with ongoing demand for skilled underground miners, trades people, and mining professionals. This discussion paper will outline the national context with regard to labour, skills and training. It will suggest options and provide an opportunity for conference participants to discuss the way forward.

Jan 1, 2007

Optimal drill and blast design is a process often neglected by many underground hard rock mines. This is even more important to the new mine where ring designs need to be implemented and refined in a short period of time. In today's environment where more and more mining is being carried out by contract specialists it is the co-operation between a principal and contractor, who are working towards a common goal, that achieves the highest quality end result. The development of drill and blast designs that cause minimal damage to the mine infrastructure is particularly important to Northparke's E26 Block Cave Mine, as it consists of a single extraction level which must survive intact for the life of the mine. The advanced undercut mining method implemented at Northparkes is fired in a sequence which protects the mine development from potentially damaging abutment stress. This paper details how blast designs will be optimised and sequenced to satisfy the conflicting objectives of maximum rock breakage inside the drill pattern and minimum rock damage outside the pattern.

Jan 1, 1995

By R J. Cuttler

In January 1998 Sydney Water Corporation formed an Alliance with construction contractor Transfield, and engineering consultants Connell Wagner and Montgomery Watson, to design and construct the Northside Storage Tunnel. The project is part of WaterPlan 21, Sydney WaterÆs strategy for cleaning up the harbours, bays, rivers and beaches within its business area. WaterPlan 21 is an integral part of the NSW GovernmentÆs $3.1 billion Waterways Package which establishes targets and initiatives for sustainable wastewater management within NSW. The project is being delivered under an Alliance Agreement, which has a number of non-traditional features in terms of partnering, management principles and design and construct. Construction began in mid-1998 and is on target to meet the completion deadline for the Sydney 2000 Olympics.

Jan 1, 1999

On 15 August 1998 the first section of the PUTRA LRT system was opened to the public as a free service prior to official commencement of revenue service on 1 September 1998. It is a remarkable achievement to open a highly advanced medium capacity urban railway scheme in four years after the outline concept began. Even more remarkable is the implementation of the next stage which is the underground section planned to be operational in mid-1999. The decision to build the first underground railway in any major urban centre is a technical challenge. The PUTRA LRT System can be likened to Hong Kong when the initial MTR system began in the 1970s and Singapore MRT in the 1980s. Prior to the PUTRA railway very little bored tunnelling had been undertaken in Kuala Lumpur. A few shallow sewer tunnels had been built but the main experience of tunnelling in Malaysia had been for water, hydroelectric and road tunnels usually through granite formations. The ground conditions in Kuala Lumpur were known mainly from experience of piled foundations and occasional deep excavations. The suitability and likely difficulties to be experienced during bored tunnelling could only be theoretically predicted. In both Hong Kong and Singapore, government owned corporations were set up to implement the scheme, but in Kuala Lumpur the whole project has been undertaken by a private company PUTRA, a wholly owned subsidiary of Renong Berhad.

Jan 1, 1999

By J Vann

Mineral Resource and Ore Reserve estimation is a challenging and demanding field, requiring application of professional knowledge, skill and experience of the highest order. If the many potential pitfalls are to be avoided, however, there are two other requirements which are of equal, if not greater, importance:good communication, and common sense. Estimation of Mineral Resources and particularly of Ore Reserves is almost always a team effort, involving a number of disciplines. Good teamwork requires good communication, both between team members and between the team and other parties having an interest in the process. Breakdown in these lines of communication can have far reaching effects on the project under consideration. The need to use common sense during a Resource or Reserve estimation exercise would seem to be self-evident. It is surprising, however, how often rigid adherence to procedures and methods prevails at the expense of clear thinking, usually with adverse and sometimes fatal effects on the project under consideration. This has become increasingly true as computerised methods have assumed a central role in Resource/Reserve estimation. The critical question that estimators should ask themselves at all stages of the process is: æIs what is being done sensible given the data available, what is known of this deposit and the purpose of the exercise?Æ

Jan 1, 1999

By A F. Cropp, D J. Bradshaw, W R. Goodall

Mineralogy and critically the texture of both the ore and gangue phases are of paramount importance in the flotation recovery of copper from porphyry ores. Mineralogy and texture will define the theoretical grade recovery curve for a feed ore. Actual grade-recovery falling below this may be due to texture and gangue influences, whilst desired grade-recovery above this line will not be possible unless the characteristics of the feed are altered.This review discusses examples of porphyry copper deposits where process mineralogy has been used to characterise these textural and gangue influences on recovery by flotation. More specifically, the influence exerted by grain size, liberation, association and elemental distribution is explored. The implications of these on overall plant philosophy and operation are highlighted, along with the subsequent potential impact on recovery.CITATION:Cropp, A F, Goodall, W R and Bradshaw, D J, 2013. The influence of textural variation and gangue mineralogy on recovery of copper by flotation from porphyry ore - a review, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 279-292 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

Crandallite and millisite in Christmas Island 'B' and 'C' phosphate ores are rapidly decomposed by sodium hydroxide solutions at about 80QC. As these phosphates generally contain less than 1% silica, an alkaline extraction process can be designed, in which up to 95% of the sodium hydroxide used, may be recycled. The insoluble residue consists of an impure, highly reactive apatite, which in pot trials, has given good responses as a direct application fertiliser; alternatively this residue can be underacidulated to give a granular product with fertiliser potential. The hot leaching solution contains up to 95% of the alumina and approx- imately half of the phosphate from the original ore. Simple crystallising techniques have been developed on a laboratory-scale to use this leaching solution for producing smelter-grade alumina and detergent-quality trisodium phosphate. As the demand for detergents is limited, an investigation was made of the reaction between trisodium phosphate and slaked lime, derived from a high-grade New Zealand limestone occurring near Oamaru. The product is calcium phosphate, containing up to 40% P205, and less than 0.2% each of iron, aluminium and fluorine, and it should be a useful raw material for phosphoric acid manufacture. A preliminary economic evaluation of the whole process looks promising, And warrants further investigations, including pilot-plant work.

Jan 1, 1971

By D Davis

The prediction of ground-borne noise levels from tunnel construction activities requires knowledge of the input vibration forces from the vibration source(s) into the cutting face, knowledge of the vibration transmissibility through the surrounding medium, and knowledge of the receiver building’s vibro-acoustic response. The conversion of this vibration energy into sound pressure within the receiver building depends upon the vibration coupling of the soil and the building’s foundations, the structure’s response including floor-to-floor attenuation and amplifi cation due to resonance, the radiation effi ciencies of the internal structural elements, and the room’s acoustical properties. Beginning with a known input vibration spectrum at the cutting face, it is possible to predict the resultant ground-borne noise levels within a receiver building using either analytical and/or empirical techniques, or by numerical modelling. This paper presents an overview of the various methods available to estimate ground-borne noise levels from tunnel construction activities and discusses the advantages and limitations of each.

Mar 8, 2011

By R L. Chaney, M Mahoney

Mine and ore beneficiation wastes and smelter contaminated soils often cause phytotoxicity and threaten adverse environmental effects if not remediated. Science has clarified both the risks from soil metals and methods to alleviate those risks that can be applied at low cost. Phytoremediation is a family of plant and agronomy based technologies to deal with environmental aspects of sites requiring remediation. If valid risk assessment indicates that metals comprise risk, phytostabilisation may be used to alleviate that risk for most contaminated sites. In particular, Zn-Pb, Cu and Ni mine and smelter sites are readily remediated by making the soil calcareous and fertile, with added organic and metal sorbent amendments that include soil microbes to ‘revitalise’ the soil. In each case, the soil fertility and causes of phytotoxicity should be clarified by agricultural soil extractions, and the combination of amendments required to improve fertility and reverse phytotoxicity identified and found locally. In contrast with phytostabilisation, phytoextraction/phytomining uses rare metal hyperaccumulator plants and agronomic management to maximise annual phytoextraction of soil elements into plant shoots for harvest, ashing and use as a metal ore. Plants that accumulate more than two per cent Ni in shoots, and yield 10–20 t ha-1 dry biomass yield 200–400 kg Ni ha-1, which has value greater than all common agricultural crops. Considering the value of elements, existence of hyperaccumulator plants and demonstrated agronomic management for Ni phytomining, it is clear that mine sites and Ni mineralised subore-grade serpentine soils can be phytomined economically as an agricultural mining technology. A team developed agronomic methods and improved cultivars of Alyssum, which can be profitably grown on temperate zone Ni mineralised or contaminated soils. Plant species for tropical ultramafic soil materials have been identified. Phytoextraction is also strongly needed to remove Cd from rice soils to prevent human disease from soil Cd.CITATION:Chaney, R?L?and?Mahoney, M, 2014. Phytostabilisation and phytomining – principles and successes, in Proceedings Life-of-Mine 2014 , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By A Tsang, D La Rosa, L Julian, W Hunt, R Pratama

Mineral extraction is facing the twin challenges of finite resources and increasing environmental and economic costs. Society’s growth is matched by an increase in demand for the earth’s resources. It is incumbent on us as contemporary mining professionals to promote and facilitate ethical and efficient practices. Technological developments have and will continue to allow a decrease in viable cut-off grades, creating new economic opportunities from deposits that were previously uneconomic. Mining low-grade deposits however, even with perfect recoveries, will have a significant environmental cost for the metal won. The greatest opportunity to increase metal with the least environmental cost is to increase the metal yield from existing mines. The determination of mining polygons is a critical juncture where rock is typically subjected to the binary grading of either ore or waste. This is undertaken using a number of factors, such as the mining equipment being used and the recovery in the processing plant. Traditionally, mining polygons were generated on the in situ grade control model. This ignores the complex differential blast dynamics that occur during blasting. Two opportunities exist to improve metal yields: optimise the blast design to achieve the post-blast muck pile that will support the greatest outcome; and generate optimised polygons on the post-blast muck pile. A data set from a Canadian Gold deposit is used to demonstrate the potential benefit of iterative blast movement modelling and grade control polygon optimisation on metal yield. The impact of blasting on the total recoverable metal is presented, highlighting blast design as a critical process in the mining value chain.

Sep 1, 2024

By P J. Howard

Atlas Iron Limited’s McCamey’s North project lies at the eastern end of the Hamersley Basin, approximately 50 km east of Newman, Western Australia, and 3 km northeast of BHP Billiton’s Jimblebar Mine. The presence of significant surface iron mineralisation identified during field reconnaissance, has subsequently been further defined by detailed mapping and RC drilling.The project area is dominated by outcrops of moderate to steeply north and south dipping banded iron formation, cherts and shales of the Boolgeeda Iron Formation overlying rhyolites and rhyodacites of the Woongarra Volcanics. In lower lying areas recent colluvium and alluvium mask the Archaean geology. Drilling and downhole geophysics has allowed a composite stratigraphic section to be compiled through almost the entire Boolgeeda Iron Formation.Surface orientations and subsurface stratigraphic correlations using natural gamma logs indicate large scale open folding about east-west trending fold axes across the project area; while small scale tight to isoclinal folding with similar fold axis orientations are visible at the outcrop scale. These folds are cut by a number of moderate to steeply south-dipping normal faults defining a series of north-dipping fault blocks which repeat the stratigraphy across the project area.Bedded iron mineralisation consists mainly of haematite-martite and goethite ores with best results of 78 m @ 60.5 per cent Fe. Vitreous goethite is observed at the surface of the mineralised horizons. The mineralisation exhibits a strong stratigraphic control and extend down-dip up to 120 m below surface. The strike extent of the mineralisation is still to be determined. An inferred resource of 39 Mt at 58 per cent Fe has been defi ned to date (ASX: AGO 3 February 2011).The fi ndings at McCamey’s North indicate that there is potential for economic iron mineralisation to exist in other areas of Boolgeeda Iron Formation within the Hamersley Basin.

Jul 11, 2011

By Lynch K. S, Street R. P

Hamersley Iron's pellet plant at Dampier involves ore drying, dry grind- ing in ball mills, disc balling and, indurating by use of the straight grate system. After five years of operation, the plant's output has been increased from the design capacity level of 2 M.T.P.Y. to 2.5 M.T.P.Y. Steps taken in equipment modifica- tion, improvements in process control, and changes in maintenance procedures are described.

Jan 1, 1973

By G Corder

Even though most major operating companies in the minerals industry have Board-level endorsed sustainability principles and objectives, design engineers typically have no mechanism that allows them to implement those objectives in their work. In addition, the existing project management systems do not readily deliver the innovative solutions needed to address key sustainability issues, such as those related to significantly reduced carbon emissions, minimal environmental impacts, and maintaining the societal ‘licence to operate’. SUSOP® (SUStainable OPerations) is an approach for the integration of sustainable development principles into the design of mineral processes, which has been developed through the Co-operative Research Centre for Sustainable Resource Processing (CSRP). Somewhat analogous to the well entrenched HAZOP (Hazard and Operability) studies, SUSOP® is a holistic, systematic and rigorous mechanism for identifying and assessing sustainability opportunities and risks at each stage of project development - from corporate planning, through design and operation, to decommissioning and rehabilitation – without compromising financial rigour. SUSOP® was developed, tested and enhanced through its application to real case studies in the minerals industry. This development path provided significant insights into the process of identifying and evaluating opportunities for improving an operation’s contribution to sustainability and its long-term business case.This paper will discuss the need for a methodical approach for integrating sustainability principles into mineral processing plant design, present the key elements of SUSOP®, and outline its development path through real case studies. In addition, the reasons why such an approach will have growing importance into the future will be raised.

Aug 8, 2011

By S M. Jowitt, G M. Mudd

"The mining industry is the source for the vast majority of the metal, mineral and energy resources we use on a daily basis. New deposits are discovered over time and are developed into mines before being rehabilitated – a sequence that when repeated can help contribute to the noble notion of ‘sustainable development’, despite the generic concept of mining being the unsustainable consumption of non-renewable resources. The scale of the modern mining industry is immense – from iron ore and coal to base and precious metals, modern mines are sometimes hundreds or thousands of times bigger than their long lost historic ancestors. We also live in a world with emerging and increasing demands for so-called technology metals (aka ‘critical’, ‘e-tech’ or ‘specialty’ metals) that are needed to feed the rapid growth in renewable energy (especially solar photovoltaic panels and wind turbines), consumer electronics, sophisticated military technologies and super alloys, amongst other uses. These elements include the rare earth elements, indium, germanium, tellurium, rhenium, selenium, gallium and many others, most of which had few or no known uses in the recent past. Although the mining industry has been successful in developing ever larger mines and increasing the scale of production, the key issues underlying the future of the industry are declining ore grades, increased tailings and waste rock generation, the presence of toxic or other impurities, balancing the economics of primary and secondary products, stricter environmental conditions, more difficult exploration, increasing community expectations, as well as the processing of more complex or refractory ores, let alone the recent volatility in world commodity markets. Here, we synthesise our recent research on many of these various issues, focusing on the need to link all areas within the mining chain from mineral resources through mining to environmental performance in order to ensure we obtain the most out of our modern mining effort. The paper presents a unique and detailed assessment of the sustainability challenges and opportunities facing modern mining – and geometallurgical thinking is at the heart of this conundrum.CITATION:Mudd, G M, Jowitt, S M, 2016. From Mineral Resources to Sustainable Mining – the Key Trends to Unlock the Holy Grail?, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 37–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016