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By Churchill M

One of the significant changes which has occurred in the flotation sector of the minerals industry, over the last two decades, has been the successful development of the very large flotation machine. The last twenty years has seen the volume of the individual cell, available to the industry, increase by a factor of ten. Today, new mills, and existing mill modernization plans, can consider individual cell volumes as large as 85 m3 with the certainty that the metallurgical performance capability of the large machine is inherently as efficient as the smaller machine. The large flotation cell offers benefits to the user such as reduced floor space, lower total power, process control simplification, and reduced maintenance. However, the flotation machine size selection process, based on overall installation economics, must include such factors as process tonnage, flotation kinetics characteristics, and metallurgical performance objectives. This paper discusses the flotation machine size and circuit arrangement selection based on both metallurgical performance and economic considerations. A computer based flotation kinetic analysis technique, which has proven valuable in quantifying the metallurgical response of flotation circuits having different cell sizes and number, is utilized to illustrate the selection of cell size and arrangement best suited to a client's Requirement.

Jan 1, 1991

By Corbett GJ

Comparisons between individual SW Pacific Rim gold deposits have facilit-ated proposal of a new classification of porphyry-related mesothermal gold deposit types. Carbonate base-metal gold systems form at relatively high crustal levels, peripheral to porphyry intrusions. There is a spatial assoc-iation with major structures which focus fluids from degassing porphyries at depth. Milled matrix intrusive breccias and extrusive maar volcano/ diatreme breccias form as a result of pre-mineralisation phreatomagmatic eruptions. These focus degassing magmatic fluids by the provision of fracture ground preparation, typically within competent host rocks, adjacent to the breccia bodies. Local dilational structures control the form of individual deposits which may contain bonanza gold grades at sites of fluid quenching and/or repeated mineral deposition.Early quartz veining and porphyry-related alteration is common and later gold mineralisation typically occurs in association with carbonate veining and Fe and base metal sulphides as Zn > Pb > Cu. The progressive cooling by mixing of the upwelling mineralised magmatic fluid with descending bicarbonate waters, produces characteristic zonations in carbonate compositions. These vary with distance from the porphyry source, from Ca through Mg, Mn and distal Fe types. Gold mineralisation is preferentially distributed within the Mn/Mg carbon-ates.

Jan 1, 1994

Most of the copper deposits in the Lachlan Geosyncline fall within areas having either a common host rock, mineral assemblage, form of ore body or time and method of emplace- ment. On this basis a Cobar-type ore has been recognised in the deposits of the Cobar -- Mt. Hope - Melrose region. The copper ores in the Tottenham-Girilambone area to the east have a different mineral assemblage. In the more rugged Central Highlands nearer the coast copper deposits are generally concentrated either in one of several Ordovician andesite belts, particularly between Wellington and Woodstock, or within Silurian acid volcanics developed in irregular fashion over a considerable portion of this region. In only a few instances is copper known in the granite batholiths which adjoin these volcanic belts. Native copper and magnetite are characteristic of the deposits of the andesite province and it is possible that future mineragraphic studies will indicate significant differences in the base metal sulphides of both the andesitic and the more acid volcanic belts. Ores having similar mineralogy and form to the Captain's Flat deposit are known at various localities in the eastern segment of the latter belt. In the Gundagai area several small copper deposits with associated nickel minerals have been developed in the Coolac Serpentinite belt.

Jan 1, 1969

By M Gao, V Lawson, W Valery

Changes in metal prices and mine output over recent years have required the Copper Concentrator of Mount Isa Mines to operate at annual tonnage rates varying from 4.0 million to 6.5 million tonnes. Several circuit combinations were operated during this period utilising up to two semi-autogenous grinding (SAG) mills and up to two ball mills. The aim was to maximise grinding efficiency and keep unit costs constant regardless of throughput rate. Measures to improve the SAG-ball mill unit operation were implemented with each circuit change. These included installation of a splitter to divert SAG Mill cyclone underflow back to the mill, increase SAG ball charge from four per cent v/v to eight per cent v/v, reduce in SAG top feed size and increase of ball mill grinding medium size. Modelling work and surveys led to a new design of the SAG liner profile from 60 rows of rail bar liners in a high-low arrangement to 40 rows of top hat liners in a high-high arrangement. An on-line SAG Mill feed sizing monitor was recently installed to improve grinding control.

Jan 1, 2000

Hamersley Iron Pty. Limited mines and pro cesses iron ore from two orebodies at Tom Price and Paraburdoo, situated in the North West of Western Australia. Conventional open pit mining methods are used at both sites in that material is drilled and blasted in benches, loaded by shovels and hauled to the Primary Crushers or dumped on waste or low grade material stockpiles. The present drilling fleet, consisting of eight high capacity Bucyrus Erie Rotary drills has evolved from an initial fleet of a large number of small percussion rigs. There are significant physical differences between the ore types encountered at both mines which nec- essitate the drilling of smaller diameter blast holes at Paraburdoo than those at Tom Price. The drilling practice at each site is dis- cussed, with examples of performance achieve- ments under varying drilling conditions.

Jan 1, 1978

By Dixon CA

In the early 1970s, Jim Walter Resources, Inc. (JWR) embarked on a coal mine expansion program that was unparalleled in the history of the United States. With a small nucleus of people then operating two rapidly depleting captive mines, action was initiated to develop four of the deepest mines in the United States. Because of the depth of these mines, operational and technical problems were anticipated. However, because of the high quality of the coal (Blue Creek Seam), the financial risks involved were acceptable. The total investment to get the expansion program completed (to get the new mines to full capacity) would represent an investment of over US$ 500 million.By the end of the decade of the 1970s, the Company had grown to 2100 employees who were producing 1640,000 tonne of saleable coal per year, a productivity rate of 3.9 tonne per man-shift. This productivity rate was not sufficient to maintain a profitable, viable organisation. Therefore, if the operations were going to survive, it would be necessary to improve productivity tremendously, a task which would tax the resources and imagination of all employees.

Jan 1, 1991

By A Torpy, N C. Wilson

Improvements in electron optics, field emission gun design, and X-ray detector technology have led to the development of a new class of microanalysis tools. By combining multiple wavelength dispersive (WD) spectrometers, spectral energy dispersive (ED) spectrometers and cathodoluminescence (CL) data sets, a wealth of information can be collected during routine electron beam mapping and analysis. In this paper, data collection on a field emission electron microprobe equipped with five wavelength dispersive, two silicon drift energy dispersive X-ray spectrometers and a wavelength dispersive linear array optical spectrometer has been automated with the optical, electron and X-ray signals being collected in parallel. To analyse the large hyperspectral data sets we have implemented an autoclustering strategy that can be used to produce a quantitative chemical phase map. The cathodoluminescence spectra can be deconvoluted to produce peak intensity maps, which are then converted into elemental speciation images with quantitative sensitivity down to parts per million levels. Both methods are illustrated using typical mineral processing examples, firstly a Ni-laterite sample is investigated with the fine-scale distribution of Ni examined in detail. Secondly, a scheelite sample with rare earth zoning in mapped and rare earth levels quantified.

Jan 1, 2008

Companies involved in the mining industry are exposed to risks, referred to as corporate risks, as part of the business process. Directors and management should be aware of these risks and make appropriate business decisions to address each risk. If business risks are not addressed on a timely basis the consequences are likely to be serious and will adversely impact the ultimate success of the business.The key corporate risks are:Poor cash flow and treasury management. ò Incompetent or unmotivated staff.ò Poor product quality.ò Accounting systems that do not provide meaningful and timely information.ò Computer system deficiencies. ò Ineffective credit screening.ò Assets not adequately protected.ò New ventures undertaken that are either inappropriate or not adequately researched.Exposures to corporate risk should be dealt with by Directors and management by systematically identifying major risk areas and implementing appropriate internal and management controls to deal with such risk areas. Proper management controls and procedures include the setting of overall corporate objectives and policy, monitoring adherence to such policy, establishing early warning systems to highlight problem areas and maintaining security over assets.

Jan 1, 1990

By Miskelly N

The Joint Committee of The Australasian Institute of Mining and Metallurgy (AusIMM) and the Australian Mining Industry Council (AMIC) have published a Code for the Reporting of Identified Mineral Resources and Ore Reserves. The Code is the result of an initiative begunin 1971 to achieve industry self regulation of Resources and Ore Reserves reporting which resulted first in guidelines for reporting standards but which have now been incorporated in ASX Listing Rules as a Code withsignificant sanctions ensuring compliance. This paper describes the background to the Code, its key provisions, and comments on practical aspects of1 working with the Code and compliance issues.

Jan 1, 1990

Natural gas from the south west Queensland gas fields is now available in north west Queensland to fuel the development of many Carpentaria Mineral Province projects. Like these projects, the south west Queensland gas project, developed under the operatorship of Santos Ltd, has its own æMining CycleÆ. While the project is entering its third expansion phase, it is at the same time actively extending its discovery phase, with large programs of gas exploration and reserves definition. This paper outlines the history of the south west Queensland gas project, with particular emphasis on the relationship of the project to north west Queensland.

Jan 1, 1998

By A J LYNCH

It was Harold McMillan, Prime Minister of England 30 years ago, who used the phrase "The Wind of Change" to describe political events in Africa in his day. So well did this phrase capture the spirit of the time that it echoed around the world, and the echo has never stopped. Change is the constant factor in the society in which we live and everyone of us has had experience of the effect which it has had on our professional and personal lives. Change will not stop, it will continue at an increasing rate and the questions we must answer are how do we prepare ourselves to meet the challenge of future change and how do we take advantage of the opportunities which it will bring? It is these questions which I wish to discuss in this address.

Jan 1, 1989

When a major mineral find has been announced the general perception is that a battle between Aborigines and the mining company involved will inevitably occur.It is a fact that many miners in the past have not had a good relationship with Aborigines because of their indifferent attitudes towards them. They saw no common future and went their particular way. However, attitudes have changed significantly since Noonkanbah and both miners and Aborigines are seeking common ground in order to achieve mutual benefits from the establishment of a mine on or near Aboriginal land. There are many obstacles that both miners and Aborigines need to overcome inordertofindthiscommongroundtoachieveawin/win situation. The obstacles can be found in entrenched ideas and practices which need overhauling, not the least of which emanate from government policy and requirements.Without going into specifics, the Noonkanbah incident during the 1970's where Aborigines and their supporters confronted miners who were ordered by the Western Australian governmentto drill on Aboriginal land, polarized Aborigines and miners. Since this incident, many Aborigines, particularly those in the cities, have had the attitude that mining and Aboriginal culture are in direct conflict. Aboriginal opinion is generally shaped in the larger cities through mass media coverage of the opinions of urban Aborigines and their supporters. Through no fault of their own, these Aborigines were removedfromthe land of their ancestors and have notlived atraditional Aboriginal life-style for a number of generations and most have little knowledge of, nor have had involvement in, traditional Aboriginal lore and culture. For the most part these people live in awestern life-style and few still know their language. They generally have high profiles, often giving viewpoints that are wrongly considered "Aboriginal" and supposedly representing all Aborigines. This group is very different with their thought processes and values from those Aborigines who live on their own traditional lands with a traditional life-style, and practise their age old ceremonies. Their tribal values are based in their relationship with the land, expressed through complex religious ceremonial rites of song, dance and legend. Today this group is very much diminished in numbers but nevertheless in the region of the Gulf of Carpentaria there is a high proportion ofpeople who practise their lore, speak their own languages and pass on traditions to their children. It is well documented in the history of Australia that Aborigines have been decimated in numbers and whole tribes have been wiped out. Certainly in this region the experience has been no different.

Jan 1, 1993

By A S. Kurilko

For mines located in the cryolitic zone, thermal conditions are an important factor for all kinds of mining works, especially for ventilation of workings. In the present paper, some models of mine air heat transfer considering air distribution in a net of mine workings are developed. A combined solution is suggested for heat transfer and air distribution problems in mine workings and other underground structures located in the cryolitic zone. A software package is also presented for calculating temperature conditions in an underground refrigeration plant and for optimisation of ventilation conditions. This software uses a special 3D mathematical model to describe heat transfer in a freezing chamber between surrounding rock massif and stored product as well as between atmospheric air and the daylight surface of rock massif. A problem requiring strengthening of a backfill material and its thermal interaction with surrounding rocks during underground deposit mining by horizontal layers in conditions of the cryolitic zone is also discussed. The developed program takes into account cement consumption, geometrical dimensions of workings filled and a sequence of deposit mining.

Jan 1, 2005

A mining operation can be identified as demonstrating prudent management when a number of vital characteristics are evident.All risks and opportunities that are critical to the on-going success of the operation have been identified and are being effectively managed. All significant tasks and events are plan driven. All levels of management visibly support the policies of the operation through their attitude, behaviour and actions as well as words. Supporting evidence for required activity and the outcomes is readily available. Improvement mechanisms are working to advance the key business processes. Everyone is working towards satisfying the needs of the stakeholders of the operation. When these characteristics are integrated with the satisfaction of all legislative requirements, all industry codes and optionally all relevant international management system standards then an operation is fulfilling all the requirements of a Due Diligence Process. The majority of mining operations do not show all of these characteristics and therefore unnecessarily suffer from missed profit opportunity and constant cost pressure, less than acceptable safety and health and environmental performance and consequent poor relations with employees, unions and regulators. In these operations the characteristics to be observed are quite different.Serious incidents are occurring with no sign of a rate decrease. The operation lurches from one panic ituation to another. Management are absent in their leadership, but very active in developing rules and enforcement methodologies. The operation has no history. Re-inventing the wheel with employees who come and go at an alarming rate seems to be forever occurring. All efforts are directed at controlling the business outputs with a strong emphasis on blame. Everyone is trying to look busy to avoid the ever-present cost reduction threats. To change to more prudent management utilising a Due Diligence Process is not theoretically difficult. However it does take clear direction, focussed efforts, supporting actions with appropriate tools and perhaps most importantly an internal desire and drive to become such an operation. A Due Diligence Process is about doing the important things that have to be done, providing the understanding of why they are important, demonstrating proof of activity and effectiveness, and leading the way through effective management.

Jan 1, 1998

Exploration and mining title administration in the Northern Territory has changed dramatically over the last 20 years. These changes have occurred due to legislative amendments, technological developments, and the changing face of the mining industry. The first legislation to control mining in the Northern Territory was the Northern Territory Gold Mining Act (1873) of South Australia. In 1911, control of the Northern Territory was passed from South Australia to the Commonwealth. As a result of the mining boom which followed the discovery of gold in Tennant Creek in 1932, the Commonwealth passed the Mining Ordinance of 1939. This legislation was amended 39 times and stayed in force until July 1982, when the self-governing Northern Territory passed the Mining Act 1980. This Act is still in force and is continuously under review. The first computerised mining titles system, REGIS, was created in 1984/85 and was, to all intents and purposes, just a computerised index. Various modifications ensued, and in 1989 the Titles Database was unveiled. The database has developed to be one of the most sophisticated yet user-friendly mining titles databases in Australia. In excess of 50 companies have access to the database from their own offices. Work continues on its development and fine-tuning. The paper outlines the development of the database since inception.

Jan 1, 1994

By B Banerjee, N Kumar, S Parihar

Rampura Agucha Pb-Zn Mine (RAM) is located about 200 km to the south-west of Jaipur in the state of Rajasthan, India. Open pit mining operations commenced in 1988 and continued to 2018. RAM open pit footprint is the largest in India with length of 2000 m, width 1500 m and depth of 400 m. Development of an underground mine under the operating pit commenced in 2013, through trial mining longhole open stoping with cemented backfill was established as a preferred mining method. Nine years in operations underground mine has reached the production capacity of 4.5 MT, which represent more than 70 per cent of the ore volume mined by the pit. RAM is currently the world second largest underground Pb-Zn mine.

Nov 29, 2022

By Miller D. R

The mineral exploration and extraction industries have gained major cost and efficiency benefits from the use of computers. However these industries are now at a cross-roads with two seemingly disparate developments - that of an increasing number of complex geoscience databases and, at the same time, the merging of all known data for the particular regions at minimal cost. These two developments can be managed by the development and of an industry accepted geoscience data model and dictionary. This will provide a common basis of understanding for geoscience data through a common language and a common structure for geoscience information. Integration of specialist systems and databases can then proceed efficiently. The development of a data model is going ahead with consensus from the mining industry. This is a joint government and industry funded project and managed through the Australian Mineral Industries Research Association, AMIRA. AMIRA is a well known research broker to the Australian mining industry obtaining sponsorship for projects both from private and government groups. The AMIRA project, P431, called the Geoscience Data Model, is to be the Australian standard data model for geoscience disciplines. The requirement for a standard geoscience data model has been recognised in Australia for some time. In October 1991, the Australian Government Geoscience Database Policy Advisory Committee (GGDPAC) established a Geoscience Data Standards Working Group which drafted a comprehensive list of data categories of the geoscience area. An AMIRA project called AMDEX was established to develop a transfer standard for the mining industry data at about the same time as this committee was in operation. The first AMDEX sponsors meeting was held in May 1991. It was proposed to use the US Spatial Data Transfer Standard (SDTS) as the basis to transfer mining data in AMDEX. A limited data model of mining data to be transferred was developed for the AMDEX standard under SDTS. The Australian Geological Survey Organisation (AGSO) saw the need to extend this and develop a complete data model for the geosciences and proposed this as a new project to AMIRA. This was strongly supported by GGDPAC which lead to sponsorship of the project from most state geological surveys. The Geoscience Data Model can be broken down into separate data models for a number of geoscience themes and sponsorship obtained so far will enable models to be developed for a comprehensive set of themes selected by the project sponsors. Further sponsorship is required to enable a more complete coverage of the geoscience area to be developed. Sponsorship for the Geoscience Data Model has been strong from the geological surveys and there was some effort by GGDPAC to promote the project in these organisations. An Australian geoscience data model is of immediate use to the geological surveys in assisting the standardising of huge quantities of geoscience data held by government agencies and it is preferable that this be an Australia-wide standard.

Jan 1, 1995

By R Terracciano, J Schneider

Willemite (Zn2SiO4) is one of the main zinc carriers in several Neoproterozoic carbonate-hosted non-sulfide deposits ofNamibia and Zambia. Willemite commonly replaces sphalerite, but it may also replace the carbonate host rocks. Fluid inclusions, cathodoluminescence petrography and trace element geochemistry are crucial to distinguish between hypogene, high temperature and low temperature (possibly) supergene willemites. A global period of willemite mineralisation, extending from Cambrian to Lower Ordovician has been proposed for the southern hemisphere. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Khosrowshahi S

The objectives of grade control remain unchanged but new methods are being developed to attain them. Since the early-1990s, an improvement in the power of mine site computers has made the geostatistical tools of conditional simulation more accessible. Optimisation of the grade control process on mine sites now involves two stages: optimisation of the sampling regime and optimisation of the interpretation of ore and waste boundaries. Optimisation of the sampling regime first requires an understanding of the nature of the mineralisation and in particular the impact of particle size on the sampling precision. This relationship, termed the Fundamental Error of sampling, enables an optimum subsampling protocol to be defined for the sample preparation and assaying. However, the actual sample collection method, whether drilling or trenching, must be correctly selected and the sampling grid should be optimised. The relative costs and benefits of various alternative sampling methods and grids can be determined using the method discussed. The use of the grade control data can also be optimised. In the past ore and waste boundaries were often defined using a linear interpolation algorithm that smoothed the data (such as polygonal, sectional, inverse distance squared or even kriging methods). Frequently the relative impact of ore loss and dilution could not be estimated. Conditional simulation to generate equiprobable alternative maps (realisations) can now be adopted to address these issues. A transfer function is then used to evaluate the similarities and differences between the maps. The Ore Block Optimisation (OBO¬) process is a transfer function that produces a three-dimensional model of the optimal ore block outlines. This provides a clear guide for the mining geologist to refine and mine. The nature of the transfer function and the inputs and outputs are discussed. In the past, reconciliation has been the `acid test' for any grade control system. Any ore blocking method based on conditional simulation can make use of the exhaustive data set to ensure that reconciliation between prediction and production will improve significantly. The OBO¬ method provides a guide to the mining geologist to ensure that the best ore blocks are mined. Misclassification between ore and waste is reduced, ore loss and dilution are minimised (and are measurable) and ore is optimally assigned to stockpiles of various cut-off grades. These advantages significantly enhance mine profitability and control of the mined grade.

Jan 1, 1997

The Australian minerals sector has a shortage of skilled professionals to satisfy an industry that is experiencing renewed vitality. Graduate numbers are low throughout Australia and the world, while economic rationalisation is seeing many educational institutions downsize, or even close, their minerals-related programs. In addition to requiring more entry-level graduates, minerals producers are looking to update the skills of their current workforce to keep up with the industryÆs continuing technological revolution. To address the issue the Minerals Council of Australia (MCA) endorsed collaboration between several Australian minerals producers and a team of universities to generate the Mineral Tertiary Education Council, or MTEC. MTEC recently initiated a venture to increase the availability of professionals with relevant skills to the minerals industry. Primarily aimed at delivering postgraduate programs, the initiative will allow graduates from other disciplines to æconvertÆ to the minerals sector as well as provide professional development training to an existing work force. This venture represents a novel approach in that courses will be delivered by more than one institution and will employ innovative teaching materials with flexible and remote delivery formats. The programs will cater specially for professional development in the minerals sector, which generally requires high flexibility due to the nature of work conditions and locations.

Jan 1, 2004