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By M Chen, W S. Ng, Y Liu

In the processing of refractory gold-bearing sulfides, pressure oxidation (POX) is commonly known for its role in liberating the gold in solid-solution via oxidation of the sulfide occlusions. For deposits that contain arsenic-bearing species including arsenian pyrite and arsenopyrite, POX serves an important secondary function in the fixation of arsenic, via the hydrothermal precipitation of stable arsenates such as scorodite and basic ferric arsenate sulfate (BFAS). There have been various investigations on the impact of different POX conditions on arsenic precipitation and the stability of the formed phases, but less is known about the changes to the arsenic carrier that occur in the curing stage, which follows directly from POX. The primary function of curing is to coax the dissolution of sulfates to reduce lime consumptions during cyanide leaching, and the slurry is kept at elevated temperatures near 100°C to achieve this. While the arsenic-bearing phases are expected to undergo transformation during this stage, there has thus far been limited experimental evidence. In this study, the effect of curing time and curing temperature on the arsenic-bearing species and arsenic deportment in the POX product has been investigated. Leaching of the curing products was also conducted to examine the stability of the arsenic species in the solid precipitates.

Aug 24, 2022

Continuous improvement in environmental management assists in the achievement of sustainability goals for the processing of minerals. The use of regular internal environmental audits (scored or unscored) which form an integral component of an Environmental Management System (EMS), provide demonstrable evidence of this improvement. Case studies are presented for a number of major coal mines in the Hunter Valley, where regular internal environmental audits have been undertaken every two to three months, over periods varying from 18 months to five years. Examples of the benefits of improved environmental performance (driven by the audit process) to sustainable development are provided.The auditing process as described here for coal mines, and coal handling and preparation plants, is equally applicable to the processing of other mineral ores, metalliferous mines, quarries, and oil and gas projects.

Jan 1, 2004

By G McLeay, T Moran

Long Shaft has traditionally been seen as one of the most challenging mines in the Kambalda area with operations having been suspended by the previous owners in 1999. When mining recommenced in October 2002, the current owners (Lightning Nickel) decided that a different approach was required for mining operations in such an aggressive geotechnical environment. This paper describes how Lightning Nickel has successfully and safely operated the Long Shaft complex on a traditional mining approach, which encompasses the key learnings of the previous owners.

Jan 1, 2005

By G Harbort, C Sola

The rapid development of geometallurgy in the mining industry has occurred in relatively recent times. Its importance as an independent discipline in the mineral processing world has been emphasised and recognised. To a large degree, this is the result of a growing understanding of the ore type being processed and their application to provide better metallurgical responses in different mineral processing techniques. The development has matured from early progress through to geological knowledge and into the realm of the metallurgist and mining engineer. Working together, they have developed a powerful framework that will interpret a body of mineralisation into measurable properties.The integration of geometallurgy and operations has become of increasingly important due to improvement in understanding of an orebody as a natural system formed by a number of processes and with a definite fabric of mineralisation within different geological domain. These have to be taken into account when creating techniques that will enable operations to extract the valuable components from a distinct type of ore. Incorporation of such knowledge at an early stage of development, such as the feasibility stage significantly reduces the project risk.This paper is written from the unique perspective of a process engineer embedded within a geological team. It discusses issues such cross discipline communications and misconceptions and details the numerous tricks, traps and treasures of geometallurgy encountered during defining of the Seminco and Taysan resources.CITATION:Sola, C and Harbort, G, 2012. Geometallurgy - Tricks, traps and treasures, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 187-196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By M Noppe, I Glacken

There are many critical nodes along the mine value chain, from orebody to mineral product, and inter-disciplinary input is required to analyse the variability and uncertainty at each node in order to identify and mitigate areas of risk. Mining differs from many other industries in that the variability in the product is dictated largely by the inherent nature of the input material (the orebody). The true characteristics, including the variability of the orebody, are never known exactly and are instead based on estimates derived from sample data. A further difference is that bottom-line gains are largely controlled by world commodity prices, which can vary with time, rather than by local supply and demand issues. Methods for identifying, reporting and responding to this inherently variable raw material are discussed. These include analytical and reporting methods, equipment and software, risk analysis and reality checks (eg reconciliation). Sampling results, mineral resource and ore reserve estimates and economic assumptions are a function of the variability of the orebody. Risk quantification should be expressed as a level of confidence, which takes into account the scale or period over which the risk is being assessed (life-of-mine, annual or shorter production periods) and should convey the likelihood, severity and consequence of occurrence of a given event. The future generation of mining specialists needs to understand the entire mine value chain to better manage risks and maximise mine dollar-value.

Jan 1, 2002

By S Harvey

An inrush of water or mud into an underground mine, or sudden subsidence above mining voids represent low probability but high impact risks in underground mining. About two such incidents involving multiple fatalities or loss of production are reported each year worldwide. On average, Australia experiences one such incident every three to four years. This paper reports the development of a Standard that is intended to eliminate fatalities due to inrushes and subsidence.

Jan 1, 1998

Thank you for asking me to address you. The topic may sound formidable. Those of you with determination to go somewhere in your careers will understand that by taking geoscience, mining and metallurgy courses as students, you are declaring your intere

Jan 1, 1994

By Johnston G, Joyce C

The permitting of new mining projects has evolved into a highly complex process that must be carefully managed. Only by developing a thorough understanding of the issues involved and stakeholder interrelationships can successful strategies be developed that integrate the often competing demands of: ò regulatory requirements, ò commercial requirements, ò social/cultural needs, and ò technical issues. Properly implemented, this approach can result in: ò shortened approval timeframes, ò better project definition ò broad based community support, and ò favorably disposed government departments.

Jan 1, 1997

By G Hobart

Laboratory flotation tests were conducted to investigate the role of pH, zinc sulfate and potassium metabisulfite in the flotation of galena and marmatite in the Broken Hill orebody. Marmatite was depressed under alkaline conditions alone, however the addition of the two depressants, either individually or combined, resulted in the greatest selectivity. The use of zinc sulfate under alkaline conditions resulted in good selectivity whilst maintaining a high lead recovery. The addition of potassium metabisulfite under alkaline conditions reduced zinc recovery, but high additions reduced lead recovery. The addition of both depressants at alkaline pH produced the best result, with a lead concentrate of 72.6 per cent at 98 per cent recovery with less than four per cent zinc recovery.

Jan 1, 2005

After 15 years of operation Australian Mineral Foundation is at the cross-roads: Affected significantly in its last 21 years by Australian dollar devaluation, lower mineral industry activity and severe cut backs in the petroleum industry due to the low oil price, a re-evaluation of its goals and industry support is urgently needed. Industry support, strong at the start, has not kept pace with inflation and expectations of a totally self supporting organisation have proved impossible to sustain. Nevertheless, with a change in emphasis in education programmes, continued creative development of information services and more particularly greater awareness by industry of the services available and hence greater use of the services, industry support is expected to increase. Indeed, industry, it is believed, will accept its responsibility.

Jan 1, 1986

By L Strezov, J Herbertson

Conversion of industrial waste materials to valuable resources would essentially take part in an ecologically sustainable future. There are still large amounts of undervalued biomass wastes generated from a diverse range of industries that are disposed in landfields. They have potential to produce valuable materials and fuels, such as charcoal, bio-oils and bio-gas through thermal upgrading. In order to enhance the efficiency of the thermal upgrading process, comprehensive characterisation of the raw biomass materials is essential. We have developed a novel thermal characterisation method that utilises computer aided thermal analysis incorporated with a gas analyser. The method was applied on two biomass materials, wood sawdust and bagasse. The paper discusses the results obtained with the novel thermal characterisation technique.

Jan 1, 2006

By R Robinson

Modem occupational health practice can be described as the fitting of work to the individual and each individual to his job; perhaps a non-traditional way to view occupational health. This two-component description is achieved through the development of programs to implement and monitor specific job procedures, from the monitoring of unwanted exposures to contaminants to the auditing of mine sites. This paper is about such programs. Some attempt must be made to evaluate the effectiveness of the program and several performance indicators which are intended to measure the effectiveness of such a program are offered.

Jan 1, 1994

All sections of our community are becoming increasingly aware of the dangers of uncontroll- ed erosion associated with modern earthworksy whether they be concerned with the protection of capital structures, reforestation of mine tailings or generally the aesthetic and ecol- ogical impact. Because of the many ecological variances and climatic conditions no single technique may be offered as the complete answer. Rather that a combination of a series of techniques is nec- essary to achieve an individual end result. These techniques may appear to be expensive initially, but when considered in relation to the overall cost, and we realise that this work represents our only insurance of the stability of our project, the cost of stabilisation is insignificant. Once erosion has commenced the cost of stabilisation escalates dramatically which highlights the definite need to include the requirement of stabilisation in early design of your projects. Stabilisation should commence during construction to ensure that control of mobile soils is gained at the earliest possible time.

Jan 1, 1976

By Dai Q

The mechanism of flotation of potash ores with long chain primary amines has been assessed. Since at high electrolyte concentration in saturated brine the electrical double layers of the interacting particles and bubbles are entirely compressed, the induction time measurements confirmed the elimination of kinetic factors associated with the energy barriers opposing particle-to-bubble attachment under such conditions as could be expected. The lack of the kinetic hindrance resulted in the correlation found between the contact angles on the KCl surfaces and the sylvite flotation measured under the same physico-chemical conditions. The iep values and acid numbers obtained for various Esso oils tested as extenders in the flotation of coarse potash ore fractions confirmed the base oils with high content of nitrogen-bearing compounds to be good extender oils. The performance of such oils could further be improved by dissolving in them a small amount of long-chain aliphatic amine.

Jan 1, 1993

Environmental management of minesites in general, and management of water discharges in particular, is receiving ever-increasing attention. One key component in the successful design and operation of water management systems is to address the presence of sediment in the water being conveyed. Sediment erosion in the mining environment is often greatly exacerbated by disturbing the ground surface of vast areas of catchment. If sediment avoidance, transport, deposition or release are not adequately addressed, the impact on water management facilities can include loss of storage and hydraulic capacity, more frequent equipment replacement, increased operational costs and potentially environmentally unacceptable sediment discharges to receiving waters. An overview of sediment management within water facilities is presented here, and design of one particular approach, the use of settling basins for sediment removal, is discussed in detail. Examples are used to illustrate lessons learnt where particular approaches to sediment management have been found to be lacking. The common themes in the lessons learnt include the need to characterise hydrodynamic conditions and sediment properties in the water source, to set performance targets for sediment management, and to develop operating procedures to meet these targets under a realistic range of scenarios. The examples show how analysis of expected performance of sediment management can help with planning of operation and maintenance strategies. For settling basins, use of a simulation model that includes the effects of turbulence on settling can provide considerable benefits in optimising basin design and evaluating performance. Even in the most basic approach to sediment settling, establishing performance targets based on design flow and sediment characteristics is critical.

Jan 1, 2003

By K Haroon, J D. Speed, S P. Wood

Online analysis of continuous and batch processes has seen a dramatic increase in recent years, with examples ranging from petrochemicals to pharmaceuticals, to industrial biotechnology and food and drink. The particularly challenging environment of alumina processing has meant that instrumentation needs specific features and characteristics to be truly suitable, features such as: robustness, resistance to caustic conditions both in the analyte and the ambient environment, and reliability for long-term continuous use. Here we present the development of a novel FTIR spectrometer that achieves these requirements through the use of a static optics arrangement of mirrors, and stable diamond-tipped light-pipe probe. Firstly we give a very brief explanation of spectroscopic analysis, and the difference between FTIR and other infrared methodologies. Next we outline the novel arrangement of mirrors required to produce an interferogram without moving mirrors, and compare the benefits and drawbacks of this approach instead of conventional designs. We then share the results of laboratory analysis of synthetic Bayer liquors, with detection limits for aluminium hydroxide, sodium hydroxide, sodium carbonate and various sodium salts of organic acids. We then share the results of analysis on production samples, both in idealised laboratory conditions and then online in the process itself. Lastly we present work on in situ ultrasonic descaling solutions to avoid scale build-up and provide continuous cleaning of the probe – preventing the need for probe removal and manual cleaning.

Aug 24, 2022

Mineral policy is now generally regarded as a function reserved to government. Government is reponsible for the economic health and progress of nations, and must therefore interest itself in minerals as a basic national resource. Government should therefore identify objectives which it sees as suitable and necessary for the mineral industry so that the industry can play its part in achieving national goals. It should provide the legislative framework and policy guidelines to enable these objectives to be achieved. The essential objective of a national mineral policy should be rational development of the nation's minerals resources. To achieve this, it need not be too formal; broad guidelines are enough. But it must be dynamic, to keep pace with the changing circumstances of the mineral industry in the world scene and the changing requirements of government. It should be flexible, recognising that there is no such thing as a "typical" mineral deposit; above all it should represent the outcome of a continuing dialogue between government and industry. Both government policy and corporate planning need to be formulated on the practical understanding of the potential economic value of the mineral sector and what it can contribute to the nation's prosperity. There needs to be a common understanding of the wide range of the costs of risks that may arise through the exploration and development stages and of the uncertainties affecting ventures at the production stage. There needs to be a common understanding that the size and importance of the mineral sector is determined in the long run by the level of investment in exploration. The development of a continuing understanding between government and industry should lead to the formulation of ground rules which ensure the continuance of a strong industry able to adapt to the changing world scene and make its contribution to national growth and wellbeing.

Jan 1, 1986

Conventional blasthole sampling for grade control has acquired an extremely bad reputation for the last 50 years. The introduction of many sources of bias is a structural reality. Delimitation biases are devastating. Extraction biases are of great concern as well. Weighting biases aggravate an already bad situation. Furthermore, preparation biases are many. Some of these biases are due to the type of drilling machine that is used and are nearly unsolvable. Some of these biases are due to the sampling tools that are used and often unsatisfactory. Attempts to automate blasthole sampling at the drilling site have failed, not because it cannot be done, but mainly because it interferes with drilling productivity. As a result the miner most often rejects the idea after a few weeks of practice. Manual sampling of blasthole piles is a disaster for many reasons; some are related to the methodology, some to the selected sampling protocol, some to the training of operators, some to limited manpower available, and some to limited supervision. Furthermore, with blasthole sampling a time logistic problem is unsolvable as the miner wants the ore grade control geologist to make up his mind within two or three days at most; as a result not enough time is allowed for samplers, preparation facilities, laboratory, and resources department to perform a good job as everyone is working under unreasonable pressure. The economic impact of poor blasthole sampling for grade control has been vastly underestimated by mining companies. The resulting ore grade misclassification is responsible for severe reconciliation problems and massive financial losses every year. This paper suggests areas along this grim scenario where things can be greatly improved; however it is clear that too many problems are unsolvable. An alternative using reverse circulation drilling for grade control is suggested. A thorough analysis of the respective advantages and disadvantages for blasthole and reverse circulation drilling for grade control is presented in this paper.

Jan 1, 2008

It is suggested that if adequate knowledge is available about classifiers in closed grinding circuits, these units may be used as on-stream size analysers when equipped with suitable sensing devices. Research work which is at present in progress to enable a hydrocyclone to be used for this purpose is discussed.

Jan 1, 1967

The Century zinc deposit is located in Queensland approximately 250 kilometres north north-west of the provincial city of Mount Isa, on Lawn Hill Station and within 150 kilometres of the Gulf of Carpentaria.ThefirstMining Lease in this area was pegged in 1887. The Silver King vein is the largestvein deposit in the area and has produced lead and zinc, in addition to 74,000 ounces of silver during its history.A total of forty three veins containing silver, lead and zinc are now known, all of which were discovered by prospectors within 10 years of the first vein being recognized.

Jan 1, 1993