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The Vertical Crater Retreat (VCR) mining method was used to mine two rib pillars at New Broken Hill Consolidated Limited (NEHC) mine at Broken Hill. Experience gained in a trial VCR pillar stope was applied to the design of Panel 3CN pillar (P3CN). Restricted access and a central sandfilled plug in this pillar necessitated the use of angled blastholes and blasting of the stope in two sections. Borehole surveys and close charging supervision were necessary to block, charge and stem the spherical charges in the correct position. The laver sections of the VCR stope with rock walls attained an average slice advance of 2.2 m whereas the higher section of the st.ope between cemented fill walls attained an average slice advance of 3.4 m. Achieved fragmentation was extremely fine. External dilution was assessed at less than 10 per cent. A cement consolidated sandfill exposure of approximately 1300 m2 stood vertically with no significant slumping.

Jan 1, 1983

By B R. Bittencourt, D A. B Pasin, D Pi

Three main genetic types of hematite can be recognised at Quadrilßtero Ferrffero (QF): Micaceous or schistose hematite derived by metamorphic/metasomatic process during regional metamorphism, increasing eastward, formed under temperatures ranging from 250¦C to 500¦C in CO2-rich aqueous carbonic, high- to medium-salinity fluids. Hematite in shear and mylonite zones, showing a wide variation of fluid and temperature conditions, between metamorphic and hydrothermal conditions. Deformed quartz-specular hematite veins formed during the late phases. Hydrothermal, compact and isotropic hematite developed during a brittle-ductile regime, forming the cement of the boudinage-kink breccia and jacutinga-type of gold mineralisation, under temperatures ranging from 80¦C to 140¦C in aqueous, low- to medium salinity, oxidant fluids, resulting from the interaction of meteoric and metamorphic/metasomatic fluids. Quartz-carbonate-sulfide veins were formed slightly later, through reducing fluids.

Jan 1, 2005

In an earlier paper(l) details of a laboratory method of extracting and separating tantalum and columbium oxides from tantalite have been given. In view of the fact that Australia may have need to be self sufficient in this field it was decided to erect a pilot plant for the production of tantalum oxide in the Metallurgy School, University of Melbourne. The plant was designed for treating about 40 lb. of ore in a batch over a period of two weeks, although; because of the sectionalized nature of the process, the capacity of the plant was 40 lb. ore per week.Australia is fortunate in possessing some very rich tantalite and columbite deposits, particularly in the Pilbara District in Western Australia. The ore used in this work was obtained from a small but high grade deposit near Greenbushes, Western Australia, and consisted of lumps, weighing up to 8 lb. each, of almost pure ferro-tantalite with occasional thin veins of the very' rare' mineral stibiotantalite.The main constituents were:

Jan 1, 1946

A statistical investigation of folding at Mount Isa disclosed similar patterns in both the shales and the "silica dolomite" zones. Analysis of these patterns yields 3 groups of folds fully developed north plunging folds, fully developed south plunging folds, and flexuresrepresenting stages of development of folds. Interpretation of results indicates that a regional force from a southerly direction was responsible for the folding.The general pattern of shearing is allied to that of folding, with the exception of bedding-plane shearing. Many shears resulted from continued application of force on folds which ruptured after overthrusting. Other shears resulted from rupture of the more incompetent shale members, without associated folding. The shear pattern is consistent with the theory of a regional force from a southerly direction.INTRODUCTIONThe notes on folding and shearing presented in this paper are part of a current study of the structural geology of Mount Isa.FOLDING 1Measurement of FoldsInvestigation of folding underground involved the measurement of plunge, strike and dip of the axial plane, and the order of magnitude of each fold, together with its location and the rock type. The total number of folds measured was 701, of which 411 occurred in shale areas and 290 within the "silica dolomite" zones. All folds measured are located on main levels, from 7 level to 13 level inclusive. The sections of the mine involved are the Black Star, Black Rock and Racecourse. Detailed investigation of folds on the upper levels (4, 5 and 6) has not yet been done, but observations there suggest...

Jan 1, 1961

By Strickland R. E J

Heap leaching is establishing itself as an efficient method for the extraction of gold from low grade ore. It has the advantage of low capital costs, low operating costs and rapid startup. However, not all ores are amenable to heap leaching. It is only applicable to well oxidized ores that have reasonable permeability characteristics. Ore with excess fines or clay often display low permeability and are unsuitable for heap leaching.In this study, an attempt has been made to increase the rate of cyanide leach solution percolation by flocculating clay particles or reducing the surface tension of the leach solution. A wetting agent was found to decrease the rate of gold dissolution, possibly by presenting a hydrophobic surface to the gold particle. Flocculation of the clay increased the solution flow rate. The flocculation agent had no affect on the total gold leached but decreased the leaching rate.

Jan 1, 1992

By Reichman J, Chapman G

The features of seam gas drainage from the point of view of mathematical modelling are outlined and discussed: 1. The use of conventional single phase gas reservoir simulator for very simplified modelling. 2 Alteration of a conventional petroleum reservoir simulator into a specialised simulator for seam gas drainage. 3. Application. of a conventional petroleum reservoir simulator for modelling of seam gas drainage by the way of pseudo-functions and sacrifying one dimension.

Jan 1, 1982

By C Li

Removal of gangue minerals from ilmenite concentrates can beaccomplished by relatively low temperature roasting in controlled gasatmospheres to selectively enhance the magnetic separationcharacteristics of the ilmenite. At roasting temperatures below 800¦C the magnetising reactions are often not consistent with phase equilibria considerations. Metastable phases can nucleate and control the roasting products. In weathered ilmenites the phase assemblages and microstructures in the altered ilmenite grains can influence the roasting reactions. In this paper we give an overview of the phase chemistry of chemically weathered ilmenites and of metastable phases formed by low temperature roasting. We also report the results of roast experiments conducted in a neutral gas atmosphere. Major increases in magnetic properties after short roasting times at low temperatures were obtained for a range of ilmenite concentrates. For example heating a secondary ilmenite concentrate from Western Australia for 15 minutes in nitrogen at 600¦C gave an increase in the three kilogauss magnetic fraction from three to 92 wt per cent. The solid state phase changes accompanying the inert atmosphereroasts were characterised by combining elemental analyses withquantitative phase analyses of the ilmenite concentrates and their roast products. It was found that the phase reaction that is principally responsible for the increase in the magnetic properties of weathered ilmenites involves a transformation of disordered ferrous-containing pseudorutile to an ordered ilmenite-hematite solid solution containing typically ten to 35 mole per cent of the hematite component. Examples are given of the application of the inert atmosphere roast to effect separations of ilmenite from gangue minerals.

Jan 1, 2001

By N Robson, E Stephens

Australian mining companies are actively exploring for and developing mineral deposits throughout the world with interests in emerging markets such as Africa, Asia and South America. It is important to understand emerging market risk as this will affect the willingness of mining companies and financial institutions to invest in a country, especially with reference to their key asset, the mining licence or operating/concession agreement. Mining companies looking to develop new projects in emerging markets have different risk profiles than projects in countries such as Australia and Canada. Examples of key risks faced in emerging markets include: political û expropriation, nationalisation, contract frustration, currency inconvertibility, war, terrorism, strikes, riots and civil commotion; and legal û mining legislation, arbitration and dispute resolution, trade agreements. There is a problem in the difference in risk perceptions between mining companies, financial institutions and insurers. This can cause different stakeholders to carry out different evaluations of the risks faced by a project, resulting in confusion about the risk margin attached to any project. In a time where resource nationalisation and energy security are prompting governments to become more involved in the mining sector we run through some recent examples of mining companies that have had problems due to the key risks highlighted earlier. Importance of carrying out the right due diligence to replace perceptions with reality: early identification of risks û detailed due diligence on emerging market risks that may arise will help with their identification and mitigation, make use of companies that can help identify risks and suggest solutions, control the cost of financing û risk margin applied to a project finance loan will be influenced by the risks faced, and risk management and using political risk insurance. There are plenty of opportunities in emerging markets but it is important to recognise the associated risks. Detailed due diligence at an early stage will provide long-term benefits.

Jan 1, 2007

By Amelunxen R, Finch JA

Flotation columns represent an important addition to flotation practice. Columns have largely replaced. conventional machines in molybdenum cleaning in Canada. Columns have been successfully tested on bulk copper/molybdenum cleaning at Gibraltar Mines Ltd. A rougher cleaner/scavenger cleanercombination was shown to be capable of giving higher grades and recoveries compared with three stages of conventional cleaning. A control strategy for the columns has been developed. An interaction between gas hgldup and wash water rate has been exploited to control performance.

Jan 1, 1985

By Quayle J. E

This paper covers period from 1973 through to 1988 and the mines of West Coast Mines, Elur Mine, North Mine and Risdon Zinc Smelter, now all part of the Pasminco Group. During this period, optimisation started with one mine (West Coast Mines) producing four Product concentrates with constant steady feed to the smelter and progressed to three mines producing eight products and a smelter varying feed inputs to maximise benefits. The initial optimisation was done manually using a desk top calculator and hand drawn graphs. This ultimately advanced to the use of PC plus linear programming software and spreadsheet generating relevant graphics. The financial benefits were achieved with no capital expenditure and increased from an initial $0.5 to $1.0 M/year (1973 $'s) to $5 to $10 M/year (1988 $'s).

Jan 1, 1991

By Cairncross A. A

Papers on technical aspects of the Melbourne Underground Rail Loop project are being presented at this conference or have been presented previously or will be presented at other forums. This paper provides the framework for these papers by presenting the overall engineering tasks. The conceptual design, the special investigations undertaken, the management of the project and the construction development are highlighted.

Jan 1, 1981

Two ends of a longwall face are not only concentrated locations of equipment, but also provide ventilation and access. The roof strata stability here has an important influence on mining coal and safety. Based on field obser- vations in the gateways at Zaozhuang Colliery (Shandong Province) and model tests, the author developed a structural model of the overlying strata at the ends of the longwall face - the arc triangular cantilever plate - to which the elastic theory of plates can be applied. Factors influencing the stability of the cantilever plate and its breaking character- istics are discussed. Requirements and design parameters for supports at face ends are pro- posed, based on these factors.

Jan 1, 1986

The three systems of mining in use in the Southern Coalfield of New South Wales are bord and pillar with or without subsequent extrac- tion, longwall and shortwall. Bord and pillar with extraction is regarded as the conventional system. The application of continuous miners and powered roof supports (Shortwall) to coal min- ing has, grown in recent years from something of an oddity among extraction systems to an acceptable and viable approach in certain min- ing environments. The method can be applied in a high proportion of situations where normal pillar extraction is practised with advantages over the conventional approach. These advantages extend to both safety and efficiency aspects and also include better utilization of coal reserves. It holds hope for further gain in efficiency because its simplicity of layout lends itself to achieving the goal of contin- uous haulage towards which operators are always striving.

Jan 1, 1976

Water is becoming an increasingly valuable commodity in Australia and the mining community is finding itself competing with pastoralists, domestic consumers and industry for access to what is an essential but finite resource. This paper will provide an overview of various legislative regimes in Australia governing water resources, and will review some of the fundamental issues which should be considered by mining companies when contracting with other parties for the supply of water. The paper will focus on mechanisms to secure access to water for mining purposes, and will deal with the following issues: Grants of water entitlements under legislation û (navigating the legislative requirements necessary to facilitate the taking and use of water for mining activities) The paper will focus on the key legislative requirements for securing access to water in Queensland, Western Australia, New South Wales, Victoria, South Australia, Tasmania and the Northern Territory, and will examine: compliance with regulatory processes for securing water entitlements through the grant of water allocations, licences and permits, etc; and dealings with water entitlements (ie statutory mechanisms for transferring water entitlements on a temporary or permanent basis). Securing access to water under water entitlements through contractual means. The paper will also review of some of the fundamental issues which should be considered by mining companies when contracting with holders of water entitlements for the supply of water from both groundwater and surface water sources. These issues include (inter alia): securing appropriate rights to take and use water in compliance with relevant legislation, the necessity to protect the validity of underlying water entitlements, ensuring the security of supply for the contract term, access rights affecting water entitlements and other important issues relating to the security of water entitlements for miners.

Jan 1, 2003

By P Elliott, D Pershke

In a minerals processing context, sustainability is about using natural resources more efficiently to achieve maximum economic benefits with minimal environmental impacts. It embodies five overarching themes, which the paper will illustrate with practical examples from Australian minerals processing plants. These are:resource utilisation and materials efficiency,process waste reduction and enhancement of co-product values,reduction of water use and impacts,reduction of energy requirements and greenhouse gas emissions, andenhanced control of minor elements and toxic materials. Sustainability could be embedded profitably in minerals plant design in three dimensions: 1.technology,2.design, and3.operations. This presentation discusses a set of principles that could be applied to minerals processing technologies and provides an outline of sustainability assessment and opportunities evaluation tools. The application of the tools is illustrated through a case study by analysing a suite of nickel processing technology routes. The analysis reveals that current generation of nickel processing technologies do possess real potential to emerge as sustainability champions in integrated processing of nickel ores and concentrates, if they are designed, engineered, and operated for sustainability and adapted effectively to site specific constraints and opportunities. The paper will address data gaps and uncertainties regarding the impact of scaling up of pilot-plant performance, and provides strategies to overcome them.

Jan 1, 2006

By Flloyd J. M

A continuous oxygen probe,incorporating a SIRO2 solid electrolyte oxygen sensor which measured the oxygen potential of a small volume of gas enclosed above the melt's surface,was constructed and tested. The oxygen potential of iron-silicate slags in equilibrium with solid iron in the temperature range 1250 to 1300¦C were measured continuously for tests of up to 40 hours duration. Results were in agreement with those of previous workers using gas equilibration techniques. Tests on non- iron buffered slags proved unsuccessful due to corrosion of the probe's component in contact with the slag and an alternative material is Required.

Jan 1, 1987

By Watson F. G

As an introductory paper of a series on the Melbourne (Australia) Underground Rail Loop extension to the extensive electrified suburban railway system the paper outlines the need for the Loop, legislative background, organizational establishment, engage- ment of consultants, design control, contracts, financial aspects, example of organizational flexibility and certification and transfer of the Loop to the Victorian Railways Board.

Jan 1, 1981

By Aziz NI, Bridgwood EW, Singh RN

One of the major impacts of using modern mechanised systems of mining is the production of large amounts of extraneous dirt intermixed with the Run of Mine output. The paper out- lines a proposed system of utilizing liquid tailings from coal mines to replace imported cementitious materials used in ground control and various other safety measures. A geotech- nical and cost assessment of the proposed system are also included. The paper concludes that it is possible to utilize processed tailings to cost effectively replace imported packing material for ground control.

Jan 1, 1986

The areas of impact when employing high productivity long wall systems are reviewed and the financial implications of the most significant areas highlighted. A distinction has been made between availability and utilization. The need for more efficient delay recording, together with increasing control and utilization of the systems has been identified and the measurability of the latter discussed. The increased use of electronic delay reporting direct from the operating unit as the basis for operational control and a pre-emptive maintenance philosophy is seen as an important area of achieving higher performances from existing long wall production systems and Configurations.

Jan 1, 1988

Production of refined zinc (99.95 per cent) at the minesite without increasing greenhouse gas emissions is considered. As an example, exploitation of the full reserve of the McArthur River orebody is proposed, using the existing concentrator, whilst introducing radically innovative smelting technology. Bulk flotation of all the sulphide minerals is followed by smelting in a melt circulation reactor with tonnage oxygen. By smelting the high-energy pyritic concentrate and reacting the evolved sulphur dioxide with near-mine dolomite, a large amount of electricity can be generated. This is enough to supply all the requirements for the smelter itself, an air separation plant and a facility for compressing and liquefying carbon dioxide. Carbon dioxide is disposed of off-shore for enhanced oil recovery or by other means. The reacted dolomite fixes sulphur as an inert and environmentally acceptable solid residue. Treatment by these means leads to virtually zero gas emission smelting. The paper concludes with a vision for the future in which expansion of zinc smelting capacity is seen to be definitely needed.

Jan 1, 1998