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By T Vizcarra, G Sandoval, C L. Evans

One of the challenges in the development of mineral processing simulators is modelling the liberation characteristics of particles produced by comminution circuits. Understanding the mineral characteristics of these particles is one of the keys to predicting their behaviour in separation circuits. While more fundamental research seeks to model the non-random breakage of ores this work examines whether we can move forward now by using observed characteristics of ores to model the composition of particles generated in comminution processes. Several researchers have noted the similarity of the liberation characteristics for a selected size fraction of particulate material, whether the fraction comes from a coarse material, such as the product from a jaw crusher, or a more finely ground material, such as the product from a ball mill. In most cases these observations were reported as an aside and were not the main focus of the published work. This observed behaviour has the potential to be a useful tool for modelling the particle characteristics in mineral comminution and separation circuits, particularly as we move towards the development of multi-component models. However, before the behaviour can be used widely we need to understand which ore types follow the observed pattern and which do not. The current work examines a range of ores and identifies which exhibit the pattern of similarity of composition for particles in a given size class that has been produced as the result of a variety of breakage conditions. The impact of mineralogy and texture on the evolution of liberation characteristics for both valuable and gangue minerals is discussed.

Jan 1, 2008

By H J. J Boshoff

Pit lakes, as a final void after completing open cut mining, are in most cases unavoidable. Initial mine designs and approvals require consideration and assessment of closure objectives, legislation and stakeholder acceptance to ensure suitable understanding of the closure liability. Mining companies undertake studies and engineering during the planning, operational and closure stages of mining to identify closure options for the final voids, which would be sustainable. Without adequate planning prior to and during the life of the mine, options during the closure stage become limited resulting in costly closure works or long-term liabilities. Engineering consultants provide a specialist service in the assessment of long-term pit lake water levels and characteristics. Ongoing advances in mining methodology and technology, coupled with improved data collection and data management aid in a better understanding of the complexities in estimating long-term pit lake water levels and characteristics. Closure objectives developed during the planning stage sets the requirements for long-term pit lake water levels, which could require maintaining a water level and pit water or discharge water quality. A variety of approaches could be used to assess these closure scenarios each requiring specific data and methodologies. Typically, limited data is available during the planning stage, which results in assumptions based on past experience and relevant case studies. Closure assessments are revisited during the life of mine and leading up to the closure stage, during which additional site-specific data is available improving the accuracy of the assessments.CITATION:Boshoff, H J J, 2018. Assessment of approaches, data requirements and methodologies for estimating long-term pit lake water levels, in Proceedings Life-of-Mine 2018, pp 28–31 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

All large open pits in Australia have been mined, or are planned to be mined well below the local water table. This raises several issues that impact on mine safety, mining costs and regulatory approvals. Some pits will be æwetÆ, where they are mined through permeable horizons and where there will be measurable groundwater inflows. These will require some form of dewatering. There may also be some difficulties in the disposal of excess water. Other pits, may be ædryÆ, where they are mined through impermeable material and there are no measurable groundwater inflows but where there are stability issues related to hydrostatic pressures within the pit walls. These may require some form of depressurisation. Some pits are a combination of both. Effective management of groundwater inflows and groundwater related stability issues and the development of cost effective and environmentally acceptable dewatering and depressurisation systems requires an understanding of site specific hydrogeological conditions and practical experience in what works best for different conditions. The presentation will include an outline of the key hydrogeological factors that impact on large pits, practical methodologies for achieving dewatering/ depressurisation, and some case studies from the Goldfields, Pilbara and North Queensland.

Jan 1, 2003

A review of the most widely used global extraction sequences in sublevel is undertaken. The review includes techniques used to extract massive as well as single or multiple steeply dipping tabular orebodies. The paper also deals with thick flat lying orebodies suitable for open stoping. Techniques used to minimise the effect of stress redistributions on a global scale are discussed for all the extraction sequences analysed.

Jan 1, 2003

New and more cost-effective methods of haulage and hoisting will be needed to develop the underground mines of the future. A review of the development of technology since the 1950s shows that once mechanised equipment became available it took 25 years for appropriate mining methods to be developed and the equipment made reliable, then a further 25 years to reach todayÆs level of automation and reliability. Suggestions are made about possible areas for ongoing research with the observation that there is little research worldwide into disruptive technologies. A call is made for better organisation and presentation of the opportunities and potential benefits of new underground mining technologies.

Jan 1, 2005

By A M. Ebbels

"Underground mine scheduling decision-making has been based on production requirements, equipment productivities and the mine planner’s instincts on the best scheduling strategy for the mine to optimise the net present value (NPV) of a project.In the last few years, innovative software has been developed to optimise underground schedules based on NPV. The schedule optimisation tool (SOT) allows the user to set up scenarios based on grade, metal content, capital and operating costs.This paper discusses the results of two case studies undertaken using the SOT software to optimise the NPV of the projects.In each case study, the SOT software has been applied in two ways:using the original mine planner’s scenario and determining whether the NPV could be improved by changing resource capacitieschanging the scheduling goals to determine whether a different mining strategy would have a better NPV outcome.The outcomes of the case studies demonstrate that the mine layout and design were contributing factors to the overall improvement of the NPV and that SOT has a more noticeable impact on the NPV of projects where less sequence constraints are required, such as geotechnical sequencing and access development.CITATION:Ebbels, A M, 2016. Optimising underground mining strategies, in Proceedings Project Evaluation 2016, pp 60–65 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

The valuation of resources companies is open to a huge amount of subjectivity. Not only are valuations subject to fast changing assumptions, such as commodity prices, exchange rates, ore grades, etc., but there is also no common agreement on the methodology to be used. To borrow from Malcolm Fraser, life wasn't meant to be easy for the resource company valuer. I will demonstrate three recent examples of valuations carried out but where the market or actual transactions done show very different results.

Jan 1, 1989

Over the last 15 years the contract mining concept has developed into an integral part of the Australian mining industry. Today it is a $2 billion per annum industry with the potential to continue to grow at a rate of between ten and 20 per cent. Australian contract miners have also exported the concept overseas where growth prospects are unlimited. The industry today is at a cross-road where both contractors and mine owners must consider the current state of the contract mining industry and where it is heading. To look at the present and the future, it is necessary to look back at the history of contract mining and why it has developed. Current industry concerns can then be summarised and the areas that need to be considered to enable the industry to prosper, reviewed. The ultimate goal is to reach solutions with benefits to both the mining companies and the contractors.

Jan 1, 1996

Perseverance Mine is a part of Leinster Nickel Operation (LNO), a fully owned division of Western Mining Corporation (WMC). The town of Leinster is located 370 kilometres north west of Kalgoorlie. LNO operates an underground gold mine and mill at Agnew, 30 kilometres west of the town in addition to two nickel mines and a mill 15 kilometres east of Leinster. Both the Perseverance and Rocky's Reward nickel orebodies are mined by open pit and underground methods.The Perseverance orebody was discovered in the early-1970s. Decline development commenced in 1977 and the first ore was milled in 1978. The shaft sink started in 1979. The shaft was comissioned in 1983, four years after sinking commenced. The mine was placed on care and maintenance in 1986 and purchased in January 1989 by WMC.

Jan 1, 1992

Developing and operating mines in developing countries is never dull, but continuously challenging in terms of geology and terrain, geography and location, culture and land tenure, environmental and social issues, fiscal regimes and in some cases political risk. In addition, the rapidly changing nature of the communities with little understanding of the nature of mining at the community level requires us to continually manage issues affecting project development and mine operations with greater sensitivity. In frontier regions, people skills can become more essential than technical skills, particularly in dealing with indigenous people. Hence, managing a mining project requires a huge relationship effort.Effective communication with communities of different cultural background and proactive management of issues influencing community aspirations and desires requires not only new skills but also creativity with new concepts on how to deal with social issues under a different cultural context. The involvement of government agencies and NGOs is an important ingredient to creating understanding and collaborative approaches to common social issues. Maintaining stakeholder relationships pays in the long-run and is a useful exercise in getting information feedback from the wider community.

Jan 1, 1997

Australian contract mining as it is known today had its origins in the early-1980s. Before this time there were numerous examples of underground mine development, and specifically shaft sinking being carried out by contractors. However, these were typically international contracting companies who came to Australia for specific projects. Growth in the underground mining industry in the 1980s opened up the opportunity for contractors. Mine owners had a need for contractors who could bring technical and operational capabilities to a project combined with capital in the form of equipment. In the early years the contracting industry was dominated by smaller players who focussed on mine development. The relationship between mine owner and contractor was loose and typically contract documents were rarely referred to. Through the 1980s and 1990s the underground contracting industry in Australia grew to where today there are over 20 underground contracting companies operating in an industry with an estimated annual value in excess of $1 billion. Of these 20 companies approximately five dominate with annual turnovers exceeding $100 million. Underground contractors now provide all facets of underground mining including development and production. Over the last 20 years the underground contracting industry has been able to consistently lower costs to mine owners through a combination of:equipment productivity, labour productivity, and technical innovation.

Jan 1, 2002

Mineral exploration management has undergone major changes particularly in the last decade. Parallel to these changes in management, and partially responsible for them, have been the changes in governmental laws and regulations at both National and State levels reinforced by a highly competitive climate created by the exploration boom in Australia. The influence of overseas methods and approaches have been married to the Australian techniques resulting in a management climate which is not only familiar with the technical aspects of exploration, but is also familiar with the personnel, economic and legal phases associated with the expenditure of very large sums of money. The utilization of all the geosciences coupled with mathematical models and computer techniques for pre-selection and assessment of areas are now normal aids used in management decisions. Management techniques developed and being developed will ensure that successful exploration will be carried out if sufficient incentives are guaranteed.

Jan 1, 1974

By N LaBranche

The resurgence of Silicosis and Coal Worker’s Pneumoconiosis (CWP) in coalmines has placed the spotlight back on the management of worker exposure to particulate matter across all mining sectors (Coal Workers Pneumoconiosis Select Committee, 2017). There already exists a substantial body of knowledge on particulate matter and its impacts upon human health (National Academies of Sciences, Engineering and Medicine, 2018). The contribution of silica to respiratory disease is well known. However, it is also clear that there are major gaps in our understanding. In part, those gaps relate to the contribution to adverse health effects of mineralogical constituents in the dust (LaBranche et al, 2021a). It is also becoming evident that the size and shape of the particulate matter can affect its potential impact on human health. The University of Queensland has developed a methodology for characterising respirable and inhalable dust samples using scanning electron microscopy. Multiple samples from numerous mining operations have already been analysed using the UQ methodology. The process has been successful in showing the variety of mineralogical components and particle size distributions present in various areas of the mines.

May 5, 2022

In order to achieve optimum results for money spent in construction of new projects there is a need for mining developers to pay greater attention to cost control. Control is achieved by establishing a frame of reference, a method of checking and a means of remedial action. The frame of reference is a well coded set of budget estimates which graduate into definitive estimates as design is completed, backed up by drawings, specifications and bills of quantities. The method of checking is provided by cost engineering and quantity surveying input, at both feasibility study and design and documentation stages. Remedial action follows if the checking process reveals a need. In large complex projects where construction completion time is often of prime importance, control of costs can sometimes be relegated to second place. To avoid this it may be necessary to include specialists in cost control in project management teams. Quantity surveyors are trained specifically in construction economics and can provide develop- ers and project engineers with valuable support at all stages of construction.

Jan 1, 1983

By P Dight

Increasing the strength of backfill has been the subject of much research. In the former Soviet Union most methods concentrated on the fill mixture including chemical additives, binder re-grinding, water electromagnetic activation and the use of vibration and turbulent activation. For the most part, this research has been confined to the laboratory where the results were not representative of field conditions. These methods also were directed at increasing the mass strength and were not specifically aimed at strengthening the fill where it may subsequently be exposed for instance on the side or underneath as it required for underhand cut and fill methods of mining. In the Republic of Armenia, a method of fill strengthening known as electro-activation has been adopted. The deposit it an epithermal gold deposit which to-date has been mined using underhand cut and fill with timber support. The backfill comprises cement and pumice placed in 2.5 m lifts. Central to the method of electro-activation is the placement of the electrodes in the stope in which the polarity and the electrical potential are changing during filling. The process promotes the binding of the fill layers, the bond to the side walls and to the adjacent fill. There is a significant increase in the compressive and tensile strength. The process has been used with beneficial effects on reinforced concrete and could be used in any mine utilising hardening fills.

Jan 1, 1998

The history of the discovery. and successful development of the offshore Gippsland Basin oil and gas fields has been well docu- mented in contemporarary and more recent industry and profes- sional literature. The various articles, papers and books record fairly balanced views and comments as to the nature and results of the explora- tion effort, and factual data concerning the subsequent develop- ment of the fields and facilities concerned with petroleum production in the Bass Strait and Gippsland environment. Recommended reading for those interested in the scientific and technical aspects of the Gippsland Basin developments and the search for petroleum in the Bass and Alway Basins includes the available library contained in the publications of The Australasian Institute of Mining & Metallurgy The Commonwealth Mining Congres since 1960 The Australian Petroleum Exploration Association The Geological Society of Australia The American Association of Petroleum Geologists Various Commonwealth and Victorian Government instrumentalities Trade Journals

Jan 1, 1988

In the wake of the United Nations Conference on Environment and Development (UNCED) held in Rio de Janeiro in June 1992, evolved AGENDA 21. This document which was adopted at the Conference, provides a global action guideline for sustainable development into the 21st century.Sustainable mining requires a complete understanding of the `mineral cycle', including government legislation, mineral exploration, mining operations, rehabilitation, product use, re-cycling and waste disposal that takes into consideration associated social and environmental considerations and achieves economic objectives.

Jan 1, 1993

By Yinxiang W, Chunlai Y

In older to improve efficiency of surface pre--grouting in sealing off water in heavily water-bearing strata, such as sandstone,siltstone and limestone, several methods have been used in China, they are ; intermittent pre-grouting, adjusting pre-grouting parameters and stepwise repeated pre-grouting methods. The paper describes effect of deviation on water sealing in pre-grouting. Deviation correction measures, like mechanical, technological and changing hole position methods have been introduced with satisfactory results in practical engineering projects without increasing the volume of engineering project and without causing delay.

Jan 1, 1988

Selective leach analytical techniques applied to surface geochemical samples in the search for deeply buried mineral resources gained popularity in the late 1990s. Several commercial assay laboratories introduced their own selective leach methods, adding to the few established commercial methods at that time. Many of these laboratories promoted their methods with orientation data showing favorable responses to both precious and base metal mineralisation, concealed beneath extensive thicknesses of overburden. However, many explorationists remain confused about the utility of these geochemical methods. This confusion is due primarily to the lack of objective orientation surveys over significant mineralisation, comparing all commercially available selective leach methods and to the lack of a creditable theory explaining the formation of these selective leach anomalies. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. An orientation survey was designed to fill the first void û an objective survey over significant mineralisation. With the help of 17 mining companies and assay laboratories, an orientation survey was conducted over five significant covered gold deposits in Nevada, USA , representing over ten million ounces of gold. Hopefully the results of this survey will help provide fuel for those working on the second void û a theory to adequately explain the formation of these selective leach anomalies.

Jan 1, 2008

Ore sorting is a high capacity, low cost method of preconcentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal sub systems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry.

Jan 1, 1980