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Underground mines in Australia and worldwide are extending to greater depths. The effect of depth brings a number of challenges to mining engineers including geotechnical, ventilation, haulage and selection of mining method. The main effects of depth from a ventilation perspective are increased heat and humidity leading to reductions in productivity, occupational safety and health issues and the potential for fatalities. Numerous approaches have been undertaken over the years to mitigate against these effects. In this paper a review of various approaches to improving climatic conditions at a number of mine sites worldwide is undertaken. From these case studies it is argued that for mines at depth with the potential for a climate problem perhaps an alternative design philosophy to the established design philosophy should be utilised. In conclusion, the paper proposes some simple rules of thumb for use in mines with climate problems or the potential for climate problems.

Jan 1, 2008

By Lynch AJ

Comminution within rod mills has been investigated by izse of a matrix analysis of breakage processes. A para,~ meter, the number of breakage stages, has been introduced and cornfninut-ion within all rod mills has been expressed in terms of the¦1-number of breakage stages- and a function which des--cribes' the feed rate, mill diameter and mill speed.'The effect of variation in feed rate, feed sizing analysis and mill speed on the number of breakage stages-is-,-discussed.

Jan 1, 1963

By Heinrich CA, Wall VJ, Walshe JL

The Porgera Gold Mine, located in the highlands of Papua New Guinea, has produced over 5 million ounces of Au, since its opening in late 1990. The deposit is located within Upper Cretaceous Papuan Platform sediments approximately 25 km south of the Lagaip Fault, and is spatially and temporally associated with the 6 Ma alkaline Porgera Intrusive Complex.

Jan 1, 1995

By Tonkin D. A

Poor performance in the several stages of the magnetite recovery circuit, coupled with poor desliming through inefficient and over- loaded desliming screens, led to excessive magnetite consumption. An accurate and reliable sampling programme was established covering all outlets of the plant. Emphasis was placed on frequency of increments in an endeavour to detect extreme conditions of short duration. Systematic checking of the entry points to these outlets than identified those sections of the recovery circuit at fault, namely magnetite recovery separators and the heavy media cyclone product rinsing screens. More product rinsing water was provided, and modifications to the rinsing screens improved the efficiency of these units. Consistency of operation through automatic control of level eliminated the sudden massive losses in the magnetic separators. Load on the recovery circuit was then reduced by improvements to the raw coal desliming screens. A 50 per cent reduction in magnetite consumption was achieved.

Jan 1, 1974

By Rintoul AH

Studies of many types and purposes are being carried out constantly by mining, minerals processing and other operating companies. Frequently, the staff requirements and special skills lie outside the resources of the operating companies, and needs arise for external consult- ing services. We examine the natures of a range of studies, the factors that influence whether they be carried out in-house or externally and then discuss the manner of execution. Aspects of both good and bad practice are highlighted in order to arrive at the basic principles that give the most benefit from study work. While the bulk of the discussion relates specifically to the execution of external studies of process plant projects, many of the observations can be applied equally to the execution of studies by one department of a large organisation for another, and also to studies of capital projects other than those involving process plant facilities.

Jan 1, 1975

By Ross C

This paper uses the results of research trials by Landcare Research and Forest Research Institute and assessments of reclamation plantings at mines and other drastically disturbed sites to describe methods of enhancing restoration of native forests. The characteristics of mine and forest environments are compared to highlight the difficulties facing restoration and techniques which result in successful restoration are described. Selection of the most appropriate technique is illustrated by describing restoration of lowland beech-podocarp forest at a West Coast coal mine. The key to successful reclamation is to understand the factors controlling and limiting plant establishment and growth, then to design rooting media, surfaces and management regimes to create a favourable environment. This paper concludes with a summary of the planning and technical factors which are critical for successful restoration of native forest.

Jan 1, 1995

The kinetics of chlorination of alumina and bauxite with CO/CI2 mixtures were studied in the range 300-1100°C. The temperature of prior calcination is critical in determining the reaction rates. An optimum chlorination temperature in the range 600°C-750°C was demonstrated such that there is no increase in reaction rates with increasing temperature. This lack of rate sensitivity to rising temperature is largely a function of the influence of gaseous diffusion gradients in the porous alumina together with a progressive decrease in surface area.

Jan 1, 1976

IF lead be heated with concentrated sulphuric acid two distinct actions will usually be observed. In the first, bubbles begin to be evolved more or less rapidly from the lead, and in the second, which occurs at a higher temperature than the first, hydrogen and sulphur dioxide are evolved, free sulphur is liberated, and leadsulphate is formed. The second action may be violent and usually continues till the lead is all consumed.Attempts have been made to apply these reactions, by means of a standard procedure, as a "Flash test" for the acid resisting qualities of chemical sheet lead. The purpose of this article is to comment on the best method of performing the test, on the various phenomena which may be observed during the course of it and on the interpretation of the results when obtained.PREVIOUS WORKIn 1919, Barr...

Jan 1, 1930

By A Datar, D Mulligan

The extractive phase of broad-scale mining can have major impacts on landscapes and associated ecosystems. Post-mining ecological rehabilitation typically starts with reconstructing topography. A fairly common industry practice has been to use landform elements such as plateaus, terraces, and gentle slopes for stabilisation purposes. However, this approach can lead to the generation of fairly uniform landforms that do not necessarily reflect natural ecosystems. Previous research in undisturbed and agricultural landscapes shows that ecological attributes and diversity in microclimates is positively correlated with landform heterogeneity. An objective of this study was to investigate if those findings are still valid in post-mining rehabilitating landscapes on North Stradbroke Island, Queensland, Australia. We investigated the relationship between landform heterogeneity and status of ecological recovery. The landform heterogeneity is measured through variance in three landform characteristics (relief, slope, aspect) using remote-sensing data and the status of ecological recovery is represented by ecological indicators measured through field surveys. The results indicate strong correlations between landform heterogeneity indices and native vegetation species richness with sensitivity to the spatial scale of investigation. It is recognised that climate, substrate and rehabilitation practices act as primary drivers of rehabilitation success. However, the results indicate that, in some examples, landform heterogeneity (heterogeneity in relief and slope angles) contributes up to 30 to 50?per?cent of the variance in native vegetation species richness. While the primary drivers of ecological recovery are difficult to control over extensive areas and extended time periods, landform heterogeneity provides a tool to indirectly control the micro-environmental parameters to improve ecological recovery. Reducing the uncertainties in the choice of ecological and landform indices and the degree of landform heterogeneity suitable for particular rehabilitating landscapes would be site specific. The introduction of desired landform heterogeneity may provide a very effective tool for significant improvement in ecological rehabilitation across broad-scale post-mine landscapes, an outcome of benefit to industry, government and local communities.CITATION:Datar, A and Mulligan,?D,?2014. Do we need to change the way we set up the stage?, in Proceedings Life-of-Mine 2014 , pp 29–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

The most critical step in the development of any mining project is the completion of a feasibility study. The feasibility study has one primary goal; to demonstrate that the project is economically viable if it is designed, constructed and operated in accordance with the concepts set forth in the study. Starting from a mineral resource data base, the feasibility study will define the ore reserves, the mining methods, the mineral processing concepts and the scale of the project. The disciplined activity of developing a feasibility study leads the proponent to examine every aspect of the project, many of which might otherwise be ignored. All technical concepts will be established and the corporate philosophy with respect to organisational structure, social and environmental responsibility, infrastructure contributions and financing will be determined. All the major decisions about how the project will be developed are made during the feasibility study. The success of the project will then depend upon the assumptions and decisions in the feasibility study and the ability and empowerment of the development team.

Jan 1, 1997

As mines become deeper, the problems of heat in the workplacebecome more acute. An important response from the industry hasbeen the widespread adoption of microclimate cooling such asair-conditioned cabins. However, not all work in mines can becompleted from inside an air-conditioned cabin, and in any event,it is still important to keep the ambient air in the mine outside ofany microclimate to a safe temperature. An important method forbringing workplace temperatures under control is the appropriateuse of refrigeration. The application of refrigeration inmechanised mines has been recently described (Brake, 2001;Brake and Fulker, 2000). This paper provides an overview ofsome of the important engineering considerations in thespecification and selection of mine refrigeration plants. Thepurpose is to provide a basic understanding of refrigerationprinciples, practices, terminology, hazards and opportunities formining engineers or other personnel who may need to beinvolved in the introduction of refrigeration onto a mine site.

Jan 1, 2001

Response of a mineral to anionic and cationic flotation reagentsvaries with the nature of the mineral and the particle size. A ruleis deduced for the selection of the correct type of reagent, which leads to a simple method of testing ores to determine the possibility of separating the constituents by flotation.

Jan 1, 1963

An intensely sheared and mineralisedIzone occurs in the Quartz Dolerite Greenstone (or Younger Greenstone) mass on, the western limb of the Kalgoorlie Syncline. This zone comprises the western part of the Golden Mile and has produced the greater part of the 33,000,000 ounces of gold produced to date from the main mining belts. A study of.th e general geological and structural features gives rise to the expectation that the lode shear system,will continue southward on a pitch similar to that of the maln syncline whose axial plane may be referred to as the "Boulder Dyke". Although payable ore has recently been found further south than previously, the expectation of large quantities extending southward from the present mining areas is Problematical.'

Jan 1, 1964

By Callinan AN

Broken Hill Proprietary Company Limited have recently commissioned a 14 Megawatt power station adjacent to its underground coal mining operation at Appin NSW. The power station is fuelled by methane gas extracted from the coal seams 500 metres below the surface. The methane is compressed and cooled prior to its injection into the combustor of a single shaft gas turbine. The turbine is coupled through a reduction gearbox to an alternator. There is sufficient power generated to cover colliery load, with any excess being exported to Prospect County Council, which is the supply authority for the south western region of Sydney.

Jan 1, 1987

By K Bojarska

Examination of wastes aimed at evaluation of their usefulness for utilisation needs applying modern chemical testing methods. The XRD-XRF-ICP-GC/MS set of test methods constitutes an integrated testing system enabling ecochemical examination of wastes. As far as the problem of time-consuming operations is concerned, the offered system fits in a market-oriented field of activity of accredited chemical laboratories. Within a reasonable period of time, it allows to obtain information about mineralogical and chemical properties of wastes. It provides full range of information beginning from mineral composition (XRD) through chemical composition including the number of elements and organic compounds (XRF-ICP-GC/MS) up to the contents relating to the amounts of ingredients, both organic and inorganic in the leaching tests (ICP-GC/MS). The XRD-XRF-ICP-GC/MS testing system proves to be of particular importance in obtaining reliable results enabling to perform precise assessment (from ecochemical point of view) of wastes to evaluate their usefulness for utilisation in building materials, in civil engineering and reclamation works.

Jan 1, 2003

Investigations into the flotation behaviour of single minerals, mineral mixtures and ores at the CSIRO Division of Mineral and Process Engineering have led to the development of sophisticated laboratory flotation testing equipment. Both routine and complicated flotation investigations can be conducted in a precise and reproducible manner using procedures and equipment that have been refined over many years of conducting careful batch flotation testwork. Several important advances in flotation research can be attributed to changes in testing procedure developed as a consequence of the availability of this equipment. The flotation cell and ancillary equipment is described and associated developments and techniques discussed.

Jan 1, 1992

Increasingly, mineral operations need to manage water as a key business asset. Managing water solely as an environmental issue leaves a business exposed to social, cultural and economic risks associated with water. Adopting a company-wide strategic approach, which takes account of the true value of water will provide businesses with opportunities and risk protection. Rio Tinto has recognised the business imperative for water stewardship and has responded by producing the Rio Tinto Water Strategy. This strategy commits the company to managing water assets in a responsible manner, taking account of environmental, social and economic values. To incorporate the true value of water in site decision making, a new set of tools is required at the operational level. A key part of the strategy focuses on developing a framework to value water based on case study examples from around the Group. This paper presents progress on the companyÆs experiences in developing and implementing the water strategy.

Jan 1, 2006

By S R. Grano, J Duan, T A, D Fornasiero

We have determined the experimental rate constants for chalcopyrite particles floated from a complex sulfide ore and compared them with those calculated using a recently developed flotation model. The model incorporates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using a surface spectroscopic approach. The calculated flotation rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in flotation rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the flotation cell. We have extended this approach through the application of a property based model to an operating plant, with a satisfactory outcome.

Jan 1, 2005

By M M. Tarshan

Separator performance is evaluated by the so-called separation efficiency. The concept of efficiency in mineral dressing operations must be interpreted with considerable care. Although qualitative use of term efficiency is valid and useful, difficulties arise in expressing it quantitatively because two conflicting criteria, grade and recovery are normally involved in its evaluation. It is undesirable to express efficiency as a single value, even though this is frequently done in practice, since there are strictly speaking an infinite number of combinations of grade and recovery that can give that one value. Inefficiencies in processes can be attributed to three broad sources: mineral limitations as represented by the separability curves, equipment limitations (which prevent the maximum separation indicated by the separability curves), and human failure to minimise these inefficiencies. In the present paper, the efficiency of a two-constituent separation process has been examined. The separation process has been evaluated by comparing the sharpness factor of the actual, the absolutely efficient and the absolutely inefficient operations.

Jan 1, 2000

By J J. L du Plessis

Escalating energy and electricity costs have become one of the biggest expenditure drivers in mining operations. During the last eight years, energy costs have trebled when expressed as a percentage of total running cost in South African mines. Power consumption on mines is controlled by three main strategies, namely load clipping where energy use is reduced for parts of the day, load shifting where energy use is shifted to other parts of the day, and energy efficiency where energy use is reduced permanently.To reduce the operating costs of ventilating and cooling underground mines continuously, system optimisation studies must be completed. A part of this paper describes methods that can be used to reduce energy usage by optimising cooling and ventilation systems during planning and in existing operations using network simulation models that accurately reflect the current and planned ventilation conditions. These models are used to examine various options for improving the overall ventilation and cooling efficiency. Furthermore, an overview of refrigeration and cooling practices, and ventilation strategies is presented.Ventilation-on-demand and cooling-on-demand strategies have the potential to reduce both the capital and operating costs associated with mine ventilation and cooling systems. In addition, it has been proven that modern strategies and energy-efficient tactics are technically feasible.It is also important that the correct equipment selection is made. This must be based on the best technology with the highest energy efficiency. Where equipment replacement is being considered, energy efficiency must be one of the key decision drivers.In this paper a number of studies were presented and from the experience and the data presented it is clear that a large financial benefit is possible through optimising ventilation and cooling during the planning of mines or within an existing operating mine.CITATION:du Plessis, J J L, 2015. Strategy and tactics implemented to achieve energy-efficient ventilation and cooling of mines, in Proceedings The Australian Mine Ventilation Conference, pp 9–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015