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By B Yeganeh, A Sam, A Kohsari

The base of separation at Gol-e-Gohar iron ore plant (Sirjan in the south of Iran) is magnetic separation after milling. Magnetic separation in the plant is divided into two parts: dry magnetic separation and wet magnetic separation. Sixty-five per cent of the plant production belongs to the dry magnetic separator section. Therefore, investigation of this part of the plant is necessary. Prediction of plant production is one of the most important subjects in mineral processing plants. That means, before feed enters the plant, specification of production has been calculated with laboratory methods. The purpose of this paper is the prediction concentrate quality has achieved from the dry magnetic separator. The content of iron in the final dry concentrate will be predicted, with laboratory, pilot and modelling methods, before feed enters the plant. Different variables are used in this approach, which consist of: speed of the first dry magnetic separator (rougher), speed of the third dry magnetic separator (cleaner), iron content in plant feed, size of 80 per cent passing of feed, size of 20 per cent passing of feed and iron content in pilot dry magnetic separation concentrate that performs in a standard manner. The artificial neural network is used for modelling and one of its branches is the radial basis network (RBN). Iron content in magnetic separating concentrate in plant will be introduced as the target and will be calculated with the RBN method. In the RBN method, a set of data enters to neural network and they will be trained and simulated. Finally, the target will be predicted. Ultimately, the original target (actual iron content) and the predicted target (predicted iron content) compare and error of them will be calculated. The obtained result is acceptable and satisfactory.

Jan 1, 2007

Gold was discovered at Waihi in 1878. In 1987 the modern Martha Mine opened in the middle of the town of Waihi. Newmont Waihi Gold as the current licence holder has been operating the mine since 2000. The current open pit was scheduled to stop production in mid 2006. An underground mine is currently being developed to the east of the town.   In 2001 serious subsidence issues from historical underground mine workings outside the mining licence and the forecast closure of the open pit acted as a catalyst for the development of new communication initiatives.   In this context Newmont Waihi Gold and the Hauraki District Council initiated a community consultation process with the people of Waihi. The Waihi Community Consultation Committee (WCCC) was established in May 2003. After an initial brief to act as a forum for community participation in closure and rehabilitation of the Martha Mine, the group quickly took on a much more proactive role working towards the long-term social, environmental, cultural, economic and spiritual sustainability of Waihi.   In the course of over three years of meetings all groups represented on the committee have presented their views, developed ideas and established an organisational structure to bring those ideas to fruition. The challenge now is to work together to consolidate likely options, seek sources of funding, produce business proposals and implement the plan for the future of Waihi.   This paper backgrounds the experience to date and describes the outcomes of the process. For more detail on process considerations this paper should be read in conjunction with Part C by process facilitators, T Clark and S Stewart. For more detail on progress towards the groupÆs goals and future possibilities, this paper should be read in conjunction with Part B by Vision Waihi Trust CEO, E Morrow.

Jan 1, 2006

In the past decade several significant intrusion-related gold deposits have been discovered in terranes historically exploited for tin-tungsten mineralization (eg Tintina Gold Province, Yukon and Alaska, Tasman Fold Belt, Australia and the Altaid orogenic collage in central Eurasia). This paper presents new data on the geological and geochemical characteristics of these deposits that links them to magmatic-hydrothermal processes and highlights their implications for exploration. New data from several intrusion-related gold provinces suggest that these deposits are found in areas that contain granodiorite to granite, but with a locally significant mafic component, have Rb/Sr ratios ranging between 0.1 and 1.0, and are moderately reduced (Fe2O3/FeO ~ 0.1 to 0.6) ilmenite series, metaluminous, I-types. The intrusions are distinct from porphyry copper intrusions and tin granites, but are more akin to tungsten granites. Hydrothermal fluid types vary with depth of emplacement in intrusion-related gold deposits and new proton induced X-ray emission (PIXE) data from syn-ore fluid inclusions in shallow and deep deposits provide fascinating insight into the variation in metal content between the different settings consistent with observed deposit metal associations. Exploration for intrusion-related gold deposits in tintungsten terranes should focus on regions that contain both mafic and felsic intrusion that are moderately reduced, metaluminous, I-type granites rather than terranes with dominantly highly fractionated, strongly reduced, peraluminous S-types. Intrusion-related gold systems occur in variety of deposit styles (in part controlled by host rock, proximity to granite, and depth of emplacement) and exploration geologists need to be aware of the variety of target types in and around the intrusive environment, and be able to recognise whether they are exploring a shallow or deep intrusion-related gold setting.

Jan 1, 2005

Future climate variability and change will impact on mining operations and their attendant communities. To minimise this impact, early and informed risk management is warranted. However, research into the risks posed by climate to the Australian mining industry has so far been limited. We are conducting a systematic study of the mining life-cycle to identify the main areas of vulnerability and adaptive capacity of operations and communities. This project aims to assess what adaptation activities are currently being undertaken within the mining industry and its communities across Australia and to develop a risk management approach that will aid the adaptation of practices in and around the industry, better assuring the security of people, jobs, revenue and the environment under changed or extreme climate conditions. The Canadian mining industry was recently assessed through a similar study, which found that many mining companies perceive a real risk to mining from climate change in the future, despite few companies being actively involved in managing such risk. At a workshop held by CSIRO involving mining specialists, the most vulnerable stage in the mining process in the Australian context was assessed to be production. In particular, impacts on water and energy supplies and also transport and infrastructure were of high concern. Additionally, heat stress on workers and equipment, changes in groundwater flow and increases in geohazards were also identified as important factors in the short and long term if problematic climate events become more extreme or more frequent. Risks in the planning and post-mine stages were also identified. Based on literature reviews and preliminary discussions with mining experts, here we present an initial assessment of the climate adaptation issues relating to mining and its associated communities and describe our future work plans in this area.

Jun 1, 2010

The mining industry has had lengthy experience with risk management involving technological situations imposing risks to people and property. In such situations the relevant parameters can be fairly well defined, the outcomes can be broadly predicted and probabilities of these can be estimated. Accordingly quantitative risk assessment can be applied. In recent years there has been increased emphasis in risk management on a broader set of potential consequences. These include potential impacts on the flora and fauna of ecosystems. These are typically poorly understood and this is especially true in Australia where the vast size of the continent and sparse population make gathering a comprehensive data base on biological resources a difficult task. The resulting scientific uncertainty and ignorance regarding the potential for serious or irreversible harm to the environment mean not only that quantitative risk analysis techniques are not appropriate, but also that the precautionary principle (PP) needs to be applied as a complement to qualitative ecological risk analysis. The potential for significant impacts is particularly high in Australian ecosystems. These comprise one of the 12 æmegadiverseÆ regions of the world in terms of biodiversity and, hence, have global significance. Moving from risk management to application of the PP by the mining industry provides a significant challenge. Application of the PP has no clear guidelines to follow and, to-date, has been highly unpredictable. However, there is much to be gained for industry in embracing this challenge and taking a pro-active approach in exploring methods that will provide for clearer guidelines and hence more certainty in outcomes of environmental management decisions involving precaution. As well, there could be considerable other advantages for the mining industry in terms of reputation assurance, community acceptance and greater certainty in terms of access to resources.

Jan 1, 2000

The recent trend of installing flotation cells with volumes as large as 200 m3 in concentrators is driven mainly by economic considerations such as lower capital, operating and maintenance costs. Despite the economic advantages, the metallurgical benefits from these large cells have not yet been fully realised by the industry. This is mainly due to the lack of understanding of cell operation, viz cell mixing and hydrodynamics, gas dispersion and froth transportation behaviour in large cells. There is still no rational basis for selecting optimum cell operating conditions and down-the-bank operating profiles. The relationship between cell operating conditions and metallurgy is not well established. This has resulted in poor utilisation of cell capacity in many operations. The present trend of installation of fewer cells in a bank requires each cell to be operated very efficiently. Optimisation of cell operation provides an opportunity for significant metallurgical improvements in a flotation circuit with minimal capital expenditure. Extensive work on optimising of cell performance has been carried out at various Teck Cominco operations in Canada, Peru and USA. Three different levels were involved in this work. The first level was aimed at identification of cell operating conditions for optimum mixing and hydrodynamics, gas dispersion, entrainment and froth flow behaviour in individual cells. The objective of the second level was to identify the optimum bank operating profile for cells down the bank in a circuit. The third level then focused on controlling these cell operating conditions and bank operating profiles for tighter control of concentrate grade and recovery for optimum bank metallurgy. This paper presents some of the major findings at all three levels and demonstrates the importance of each level in optimising the performance of flotation banks installed with large cells.

Jan 1, 2005

By T J. Sheer

Water vapour refrigeration (systems using water as the refrigerant) could potentially be used to provide chilled water at underground locations in mines, as an alternative to conventional refrigerators using refrigerants such as R-134a. The use of water as both the primary and secondary refrigerants is attractive in concept since direct-contact heat exchangers could be used, yielding higher coefficients of performance. The disadvantage of water is the very high specific volume of the vapour at low pressures, which leads to great challenges in compressor design, as has been reported previously in the context of slurry-ice plants for mine applications (Ophir and Koren, 1999). Steam ejectors have long been known as alternative compression devices for refrigerators, but no work has been done previously on the possibility of using ejectors powered by high-pressure water, which is readily available in mines from long pipe columns in vertical shafts. This paper presents the results of a laboratory investigation into the use of high-pressure water as the motive fluid in an ejector refrigerator. No previously reported liquid ejector system has achieved subcooling of the process fluid, ie a reduction in fluid temperature within the evaporator to a level below that of the motive fluid. In contrast, the present work demonstrated that subcooling could occur at motive water pressures above 5 MPa. Mine cooling applications were considered and it was concluded that while this concept would not be feasible as a mine-wide cooling source, there could be specialised applications where it would be beneficial. One application would be to cool backfill and thereby reduce the heat load at the working face. In this case the best performance would be achieved by using the ejector in combination with an energy recovery system such as a Pelton turbine or a three-chamber pipe feeder.

Jan 1, 2005

Although this is a symposium on "The Occurrence, Preparation and Use of Australian Black Coal", I do not think that, in these days, any of the main energy resources can be considered only in terms of country of origin or only by itself in isolation from other energy resources. Accordingly, I propose to comment on solid fuels generally in the world energy scene, and make some brief references to Australian solid fuels, and to some other matters in the latter part of this paper. In this address I am drawing heavily on the 1974 survey of energy resources published just recently by the World Energy Conference. I do this for a number of reasons. Firstly, the survey is the latest and most comprehensive publication of its kind; secondly, it is the result of several years' work by a panel of eminent people, from all the energy industries and from some 16 widely spread countries; thirdly, substantial assistance was given by the U.S. Atomic Energy Commission in its compilation; and, finally, to let all know of the existence of the book, as I believe it to be a source document for all those interested in world energy resources. The United Nations "J" series of statistical papers provide important information on the annual production and consumption of and trade in the various forms of energy. In their respective areas, these two publications are primary information sources. Our present sources of energy throughout the world are fossil fuel deposits (coal, oil, gas), nuclear materials, water, geothermal, solar and tidal - but we are at present heavily dependent upon the natural stores of non-renewable fossil energy resources. Fig. 1 shows the changing use of energy resources in the present century. A comparison between 1900 and 1973 shows clearly the shift which has taken place.

Jan 1, 1975

By M Battersby, F Parra, S Sanchez-Pino

Pneumatic flotation, as developed by Dr Rainer Imhof, has been applied in commercial beneficiation operations since 1987. Over 85 flotation cells have been installed in more than 30 operations, successfully beneficiating a wide range of minerals. Pneumatic flotation is however still considered as a non-conventional flotation process. Due to its highly selective nature in operation it has generally found its market in difficult applications where conventional flotation equipment has struggled. Compa±fa Minera Huasco (CMH) operates an iron ore pellet plant in central Chile. CMH desired to produce a low silica pellet for the export market where the SiO2 grade should not exceed 1.5 per cent. It is common practice in other countries to float quartz from hematite with relative ease. However, the silicates contained in the magnetite ore of CMH are only present as quartz in small quantities and the major undesirable silicates are difficult to float. CMH spent considerable time on developing a reverse flotation process and a reagent suite to try and reduce the silica content to acceptable levels. However, extensive laboratory and pilot plant tests with conventional mechanical tank type cells and with column cells failed to produce the required reduction in impurities. A series of tests with pneumatic flotation cells indicated that this type of flotation technology could achieve the required silica target. A 500 tph Imhoflot pneumatic flotation plant was subsequently constructed and successfully commissioned by CMH, making it one of the largest iron ore flotation plants in the world. This paper details the background and testing that was undertaken by CMH which led them to choose pneumatic flotation as the preferred process and compares the test results with that achieved in the industrial plant.

Jan 1, 2005

By Guarascio M, Massacci P

In process simulation, more reliable prediction of industrial results and evaluation of data for design purposes and process optimisation may be attained by the combined use of: the modelling and simulation of ore characteristics, and 2. the modelling and simulation of the process. It is well known that geostatistical methods allow the defining of models of orebodies in which the variables considered are the grades of the valuable components. These models are proper for reserve estimation, geostatistical contouring, design and simulation of the exploitation method, and, in addition, for evaluating the variability of the ROM which is expected to be fed to the processing plant. However, no data are normally incorporated in the orebody model in order to evaluate the ore characteristics relevant for a reliable process simulation. The procedure for process simulation aimed at predicting plant results normally used so far consists in collecting samples from different orebody sites and building up a so-called 'representative sample'. On this sample, the ore characteristics (eg liberation, washability, grindability, etc) and the processing tests are referred to as the 'average behaviour in the orebody', assumed constant. A more reliable methodology consists in collecting samples from different orebody sites, in performing tests to characterise the samples from the point of view of the process (ore patterns), and in using synthetic parameters (process features). The values of the parameters are processed using geostatistical methods in order to develop a model for simulating the feed to the process. The estimation may thus be referred to the amount of recoverable minerals instead of to the existing minerals. Furthermore, the selection of the processes, the sizing of equipment and the design of control devices, as well as the prediction of results, become more accurate and reliable.

Jan 1, 1993

By Bezuidenhout M, Moolman D. W

In the minerals industry numerous problems cannot be solved by conventional mathematical models owing to their complexity or a lack of phenomenological understanding. Neural networks provide one way of mapping the ill-defined relations between process variables and functions for such ill-defined problems. Consequently, processes such as leaching and froth flotation are mostly controlled in an empirical way by using rules of thumb. In addition, these processes involve so many independent and dependent variables that the plant operator finds it difficult to visualise or even observe a change in process conditions. The structure of froths developed on the surfaces of industrial scale froth flotation cells has a significant effect on both the grade and recovery of valuable minerals in the concentrate. Although these effects are well known at the process operational level, where considerable heuristic knowledge is available, little work has been reported on a detailed characterisation of the mechanisms and the visual characteristics of the surface froth. Recent results from an on-line observation of froths in several plants have proved the relationships between image features representing froth behaviour and metallurgical results. It will be shown how supervised and unsupervised neural nets are being used on operating plants to interpret computer vision data. In froth flotation the operator is supposed to visually observe process changes from the appearance of the froth, which is an unreasonable demand under industrial conditions. The system described here determines textural parameters on-line, and tracks the changes in process conditions via a Self-Organising Map (SOM) neural net. This monitoring system warns the operator about fluctuations in reagent addition, and gives an idea of the type of froth encountered. In another example, changes in the mineralogical characteristics of gold ores are represented on an SOM map, based on the diagnostic leaching behaviour of such ores.

Jan 1, 1997

There are two mechanisms in the flo- tation process by which particles are transported from the pulp to the con- centrate: bubble-mineral aggregation and entrainment. It is the chemical processes which occur in the pulp which are critical to the success of flotation since they control the floatability of different min- erals and the selectivity which can be obtained. However, these chemical pro- cesses are so complex that metallurgists are still limited in their ability to predict the floatability of particles in industrial circuits by consideration of the minerals present and the chemical environment. The alternative approach to understand- ing flotation is to examine the behaviour of minerals in industrial flotation pro- cesses, to recognise similarities and differences, and to define the "laws" which appear to apply. Using this ap- proach it has been found that minerals float at a rate which is proportional to their concentration in the pulp, and that the rate of flotation of different min- erals is influenced by variables which' affect the pulp or the froth phase. The ultimate application of this approach is the use of models for circuit simulation purposes. It is this alternative approach which is the theme of this paper. One of the most important problems in understanding the technology of flotation has been in defining the characteristics of the particles being floated. Particles entering flotation vary widely in size and mineral composition, and different par- ticle types float at different rates. These rates do not change uniformly as operating variables change. It has been conventional practice to assess flotation performance in terms of the metal contents of total streams because no better method has been available, and this procedure has obscured important effects which occur in

Jan 1, 1984

By J Kovacs

Underground development drill and blast practices have generally remained unchanged for decades. Historically, development optimisation has focused mainly on the application of perimeter control products in order to reduce overbreak, and efficiencies in development cycle times to increase advance rates. In today’s environment of ever increasing operating costs and lower ore grades, it has become even more critical to focus on the optimisation of drill and blast in development mining. It is a crucial component in ensuring mining schedules are maintained, but more importantly achieving the objective of getting to the orebody in the shortest possible time.This paper will focus on the development optimisation process used in a trial at Xstrata’s George Fisher Mine in North Queensland. Not only did the trial include the typical optimisation areas of charge loading practices, perimeter control methods, drill design standardisation and quality control processes, it also investigated the significance of delay accuracy with regards to perimeter control and drill design optimisation.One of the key measures of the trial was a comparative analysis between baseline development and development with the staged introduction of optimisation elements using 3D photogrammetry as a validation tool. A detailed cost analysis between the various stages was also a key measurable of the trial.The results of the work undertaken at George Fisher have shown that the accuracy of electronic detonators can produce significant benefits in development blasting. When combined with standard optimisation philosophies a substantial reduction in overbreak, ground support requirements and development cycle times can be achieved, whilst still being able to reduce the overall development operating costs.CITATION:Kovacs, J, 2014. Mine development optimisation – an evolutionary process, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 51–56 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

Portman Mining Pty Ltd very successfully operated the Ferro GullyNorth Mine in the Hamersley Province of Western Australia to satisfy a contract for the delivery of six million tonnes of iron ore in less than two years to the Mount Newman Mining Co Pty Ltd. The high-grade ore extracted from Ferro Gully North Mine was unusual in that, not only was it within the Joffre Member of the Brockman Formation, but it was rich in red ochreous hematite and martite and very low in phosphorus.

Jan 1, 2001

The use of black and white and colour infrared film in remote sensing of natural resources, is reviewed. In heavily-forested areas such as New Zealand, the main value of the method is in surveying the vegetation cover to detect the existence of plant communities characteristic of specific geological formations, By contrast, in and areas of Australia where the vegetation cover is sparse and where rocks and soils are well exposed, the method can be used in detecting different rock types or other geological differences.

Jan 1, 1971

Potential hlghwaJl mining reserves in Australia are large, but geotechnical and operating conditions are quite different from those where highwall mining has evolved in the USA. In order to achieve safe and effective resource recovery, equipment and procedures should be developed to penetrate 250 m in the Australian mining environment. This paper identifies key auributes to be incorporated in such machinery and methodology. These suggestions are intended to promote discussion on innovations to satisfy Australian requirements for highly productive, safe and environmentally acceptable techniques.

Jan 1, 1993

Both as an energy source and as a raw material, natural gas is playing an increasingly important role as a catalyst for the development, continuation and rebirth of mining projects in Australia. Pipelines are the vital link in making natural gas available to a region and to individual mines. This paper will cover the role of pipelines in supplying mining projects in Australia, the development and status of the Ballera to Mount Isa gas pipeline and the future prospects for gas pipelines in the Carpentaria Mineral Province.

Jan 1, 1998

In most States of Australia it is a legislative requirement for underground mines to have a separate means of egress from the normal means of ingress to permit the safe evacuation of workers to the surface in event of an emergency. Such egress may be in the form of a ladderway equipped shaft/underlie or trafficable incline/decline. Additionally, there is a general requirement to have one or more airways, separate to the main shaft or other principal entrance of an underground mine, extending to the lowest level to permit ventilation to all parts of the mine. Fulfilling these requirement is difficult in the development phase of a mine when access underground is achievable by only a shaft or decline in the process by being sunk. What is frequently practiced in Australia is for production to then commence, sometimes in association with continuing development, in the same configuration without the establishment of this separate method of egress to the surface nor additional airway/s with reliance on refuge chambers to cater for back up in any emergency. Not only, could this jeopardise the health and safety of workers in case of an underground emergency it could be construed as a statutory breach of legislation. While recognising that refuge chambers are often used throughout underground operations nowadays their equipping and the criteria for their location needs to be bought into focus. This presentation discusses how such legislative requirement can be met alongside the use and appropriateness of refuge chambers.

Jan 1, 1998

Alaska Native corporations, as representatives of the aboriginal inhabitants of Alaska, control the mineral rights to 18 million hectares of Alaska, approximately 12% of the state. These corporations were established through legislation passed by the United States Congress in 1971 designed to settle the land claims of the Native peoples of Alaska. Twelve corporations, each representative of a specific geographic and cultural region, were established and granted the mineral rights to most Native lands in their respective regions. Since that time the Native corporations have taken an active role in mineral development in the state. Generally through agreements with established mining companies, Native corporations encourage balanced exploration and development of their lands. Substantial mineral potential has been recognized on Native corporation land, which includes holdings in many historic mining districts of Alaska. Several world class deposits have been discovered on Native corporation land, including the Red Dog zinc-lead deposit, which began production in late 1989. The experience of Alaska Native corporations demonstrates that aboriginal peoples can be very positive forces in resource development.Alaska, although remotely located in the Northeast corner of the Pacific Basin, is playing an increasing role as a supplier of natural resources to the region and the world. Most of Alaska's privately held natural resources are owned by the aboriginal inhabitants of the state. These aboriginal inhabitants, now collectively referred to as Alaska Natives, have emerged in the last two decades as having a major international impact in mineral resource exploration, development, and production.

Jan 1, 1990

By A Goldstone, M Fitzpatrick

Contemporary mine wastewater flows are subject to stringent water quality standards before discharge to local waterways. Strict criteria are often applied as a result of fears of extensive acid mine drainage; a feature of the many abandoned mine adits around the Coromandel, Central Otago, and the West Coast. In most cases the USEPA water quality criteria have been used to set treated wastewater discharge water quality standards. In future it is possible that the recently published ANZECC water quality criteria guidelines will be used for this purpose. The ANZECC guidelines also provide for the establishment of discharge criteria at specific sites, rather than accept the trigger values. The use of site-specific criteria for treated wastewater mine discharges was pioneered at the Golden Cross gold mine, near Waihi, in the late 1980s. The procedure used to derive water quality criteria was based on USEPA guidelines. In developing the Golden Cross criteria, only species that occur, or are similar to those that occur in the Waitekauri River were used. The mine commenced discharge of treated wastewater in 1991, and macroinvertebrate communities in the vicinity of the discharge point have been regularly monitored twice a year for the past 12 years. Despite fluctuations in community composition and abundance over that period, no permanent significant changes in the macroinvertebrate communities occurred between sites above and below the treated wastewater discharge. The success of the site-specific criteria at Golden Cross has shown how the application of this methodology can result in the protection of aquatic life while allowing for the discharge of treated mine wastewater.

Jan 1, 2003