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By Wright G. A

The objective of refining in steelmaking is to reduce the concentration of impurity atoms, e.g. sulphur, phosphorus, from an initially high level to a specified low concentration. A two-film theory of refining is presented in which the rate of

Jan 1, 1980

Severe development difficulties were experienced soon after in-seam mining commenced at Appin Colliery in'1962. Thirteen years later no significant pro- gress had been made in overcoming some aspects of this development problem. Some success had been achieved in destressing roadways both in development and pillar extraction. Longwall retreat mining had shown promise of being highly productive but at an extremely high cost in terms of development requirements both in number of roadways and intensity of support in those roadways. No real advance was made in the problem of driving the first heading of a group of headings under conditions of apparently high stress in directions other than the preferred mining directions, although failure of the roof in this heading did seem to give easier work in the subsequent headings driven particularly if they were driven on narrow centres.

Jan 1, 1976

Acupan is considered to be an intrusive centre as several igneous phases have been emplaced in the vicinity of the mine over the past 8 Ma. They include the Lucbuban gabbro, Virac granodiorite, Ampucao dacite porphyry (ADP), Hartwell plug, Itogon plug and the multi-phase Balatoc diatreme. These intrusives have high-K calc-alkaline affinities and are grouped together as the Virac Complex.Porphyry-style mineralisation formed during the final crystallization of the ADP in the late Pliocene, with the deposition of two vein stages from high-temperature hypersaline magmatic-hydrothermal fluids. K-silicate alteration halos surround the first stage of veinlets (stage I); they are surrounded in turn by a propylitic assemblage. White sericite and/or intense propylitic halos envelop the second stage of veinlets (stage II) and grade into a weak nrnnvlitir accPmht o

Jan 1, 1990

By Sennitt C. M, Hartley J. S

The Twin Hills Gold Deposit is an example of a preserved, high level, epithermal system, with mineralisation introduced contemporaneous with deposition. The deposit is hosted within sediments of the Late Devonian to Early Carboniferous Saint Anns Formation, of Cycle 1 Drummond Basin stratigraphy, situated in central Queensland. Prior to epithermal activity in the Twin Hills region, a lacustrine fan delta depositional environment existed, together with minor tuffaceous activity. An and palaeo climate, with occasional periods of torrential rainfall, together with a basin with faulted margins, allowed alluvial fan prograda- tion. Cyclical repetitions of the fan indicate repeated faulting and seismic activity took place during deposition. Significant gold mineralisation was first intersected at Twin Hills by Metana Minerals NL in 1988, after drill testing a "blind" target outlined by geological mapping and bedrock geochemistry.

Jan 1, 1991

By Mingmin Dou

The behaviour and deportment of indium during the precipitation of sodium jarosite from Fe2(S04)3 - Na2SO4 solutions were investigated. Indium is readily precipitated with sodium jarosite, and the extent of In precipitation increases as the In concentration of the solution increases. It was shown that In 3+ substitutes for Fe 3+ in the jarosite structure to form a nearly ideal solid solution series. On a molar basis, the precipitation of Fe is slightly favoured over that of In, and the difference is reduced as the pH increases. Sodium jarosite precipitation becomes kinetically rapid at temperatures >70¦C, but increasing temperatures in the range 70 to 150¦C affect neither the relative precipitation of In and Fe nor the composition of the jarosite product. Low Na2SO4 concentrations result in reduced product yields and jarosite precipitates in which H3O' > Na+. The hydronium-rich precipitates have reduced In contents. Increasing the ZnSO4 concentration of the solution slightly increases the quantity of jarosite formed and results in the incorporation of -0.3 per cent Zn in the jarosite structure. Otherwise, the presence of ZnSO4 has no significant effect on the composition of the jarosite. Seeding accelerates the rate of jarosite precipitation but has a negligible influence on the deportment of In. The jarosite precipitation reaction at 98¦C is relatively rapid and near-steady state conditions are achieved in - 6 h even in the absence of seed. The initially precipitated jarosite is slightly enriched in In with respect to Fe. The ferric ion concentration of the solution has a significant influence on both the amount of jarosite formed and its composition. In particular, the jarosites precipitated from dilute Fe3+ media have significantly enhanced In contents. Hence, it may be possible to recover - 25 per cent of the dissolved In, at the 1000 mg/L level, in a jarosite precipitate assaying - ten per cent In by the controlled oxidation-precipitation of sodium jarosite from a ferrous sulphate processing solution.

Jan 1, 1993

Someone once said "Leadership is the ability to inflict pain and get away with it." The same can be said about successful management of equipment suppliers. Improved performance will not be achieved without some pain, but it should be evenly spread between both parties. In practically all mining situations there is a great deal of scope for improving performance and reducing maintenance costs on an extremely wide range of plant, but it requires co-operative effort. Most mine maintenance engineers attribute the main problems to the equipment suppliers, unsuitable designs, lack of spares, untrained servicemen, lack of standardisation, poor maintenance manuals, and so on. Conversely the suppliers' engineers are usually convinced that problems with their product are exclusively due to poor maintenance management, after all they never have the same problem elsewhere. Of course both are correct to some degree. My aim in this paper is to explore the opportunities for substituting collaboration for confrontation between the engineers of the mining and supplying companies. I will also propose that contrary to common belief, the mines rather than the suppliers, should be taking the management initiative needed to achieve a closer and more effective relationship, Many would argue that this initiative should remain solely with the supplier; after

Jan 1, 1980

Nearly eighteen months ago Newmont Waihi Operations joined with the local district council and members of the Waihi community in the initiation and running of a community liaison forum.   This forum û the Waihi Community Consultative Committee (WCCC) û was set up with the objective of improving communication, providing a forum for discussion and ultimately working through a range of issues relating to the future of the town and district after the projected closure of Martha Mine in late-2006.   After 18 months of meetings where all represented groups have presented their views, the challenge now is to work together to investigate likely options, seek sources of funding, produce business proposals and plan for the future of Waihi in what we call the Golden Legacy Project.   This paper backgrounds the companyÆs experiences to date, the issues the group has addressed and its proposals for the future. Methods employed to set up an effective community liaison forum are considered, drawing on specific examples from the WCCC. The actions and structures required to ensure effective and ongoing community æbuy inÆ at all levels are also discussed.   This paper develops themes addressed in Taking it to the Streets presented in 2003.

Jan 1, 2004

Routine, in-pit geological mapping of highwall at Central Queensland Coal Associates (C.O.C.A.) deep strip mines has proved too slow for the increasingly greater highwall lengths which require mapping. This realiz- ation has encouraged the search for faster mapping methods and after trial of ground photographic methods has resulted in the adoption of interpretive mapping off stereo cover, oblique -- aerial photography. This entails using a Cessna 182 light aircraft flying at its slowest speed, the aerial meth- od finally employed consisting of two Vinten, air reconnaissance cameras mounted in parallel and simultaneously taking both colour and black and white photographs of the mine high- wall. The respective 1:500 scale enlargements produced from the 70mm format films combine to present the sharpest resolution attainable under the field conditions pertaining and such information on weathered material as only colour photography can fully render. Total costs for the aerial photography method are estimated to be about the same as those for conventional in-pit mapping. Whilst total costs are comparable, geo- logist's time for mapping a 10 km. length is reduced to less than half that for in-pit mapping (for Stage 1, fully accurate mapping) and accuracy and detail are greatly improved. A permanent, accurate record of overburden

Jan 1, 1981

The implementation, during recent years, of the concept of distributing chilled water to improve cooling at the working faces represents a very important innovation for the mining world. In a logical extension to that concept it has been recognized that distribution of the cooling water at high pressure would provide a potential source of energy for driving water powered hydraulic machinery such as rockdrills, water jets for moving rock, and support props, in the workings. With this in mind, the Research Organization of the Chamber of Mines of South Africa is pursuing the development of such a dual system that will provide cooling in a deep mine and, at the same time, drive hydraulic machinery. A comprehensive design of such a system has been completed and has shown the concept to be entirely feasible technically using technologies currently available. A pilot system is working in a mine shaft 2000 m deep giving a pressure of 20 MPa at the bottom of the shaft and distributing the cold water into the workings at a pressure of 17 MPa. The system shows considerable potential for improving existing mining methods and will open the way for the development of new mining methods for deep mining operations.

Jan 1, 1986

On the first of October 1991 two significant pieces of legislation came into force. Both of these are relevant to the allocation and use of minerals in New Zealand . They are the Crown Minerals Act 1991 and the Resource Management Act 1991.   The full legal implications of these is not fully known because the Planning Tribunal and the superior courts have not as yet had to deal with them in any detail. However, the thrust of the legislation is clear and it is appropriate to give an overview of how the statutes will operate in tandem if you are seeking to pursue or oppose any prospect, exploration or mining of Crown Minerals in New Zealand.

Jan 1, 1992

By Aspinall T. O, Just G. D

Computer software systems have been developed to assist in a wide range of specific mine planning and scheduling applications. In selecting appropriate systems for any mining operation it is apparent that certain features have particular advantages for each mine site. The ideal solution to this problem is to select a range of systems which best relate to sections of each mining operation. This approach raises potential data linking difficulties where output from one system is incompatible with input requirements for other systems. A study at the University of Queensland investigated the problems related to the integration of a number of mine planning and scheduling software systems. The project used data from large scale coal strip mining operations in Central Queensland. Two major computer packages used extensively in the study were the SURPAC mine planning and XPAC mine scheduling systems. Dragline and truck and shovel operations were analysed in the project. Results of the work have been directly applied at the mine site to assist current strip design by effectively automating the design procedure. This enabled sensitivity studies to determine the effects of changing dragline working levels and varying pit dimensions. Coal blending studies and procedures to optimise operations have been investigated using linear programming within a spreadsheet software application. Output from the SURPAC and XPAC programs was directly linked to the linear program for this analysis. The simulation program GPSS/PC was also used in a similar manner to assess optimisation parameters.

Jan 1, 1992

IN any assay office it is of paramount importance to keep the men interested in their work; and in order to do this, men on routine work, such as lead, zinc, and sulphur deterrrrinations, slag analysis, etc, should be changed around monthly. This gives some variety and helps to keep a man's interest on his work, so that better work results. It may be maintained that to keep a man on the same class of work indefinitely makes him more expert at his work. This is certainly true; but in assaying, where accuracy is so essential, it is absolutely necessary for a man to keep his mind on the work, and not 'get' into a mechanical method of working. He is also on the alert to discover means for shortening his analytical methods, and his capacity forwork is increased. Another advantage is that the men get a good all-round training, and one is never at a loss to replace a man on any class of work when he is absent from any cause. This tends to smoother and more efficient running of the assay department. In industrial assaying it is often advantageous to have a result quickly, so that it will be of maximum benefit in the running of some part of the plant, In such a case it pays to sacrifice a little accuracy to speed up a method. The shortest method is less costly, and a quick approximate method is all that is required to give the superintendent the requisite information. Time is thereby saved, and the cost is less. In carrying out assaying for any large industrial plant, such as a smelting works, there is always a tendency for superintendents running the different departments to send in more samples for assay than are absolutely necessary when no system of costing is in operation. Some of these samples may involve a lot of work and heavy expenditure, as, for example, the estimation of only one impurity in a sample of refined lead. If the superintendent knows that the cost of assaying all samples sent in by,him is charged up directly against...

Jan 1, 1922

By Ghosh I, Vanangamudi M

Experiments have been made in a laboratory heavy media separator at various specific gravities of separation using zinc chloride solution and magnetite suspension as media for different types of coals. The results indicate that the magnetite bath gives at better separation than zinc chloride solution. Even though the probable error remains the same for most conditions of operation, the error area is found to have a wide variation which emphasises the importance of the error area over probable error in evaluating the performance of a cleaning unit.

Jan 1, 1981

By A Morris

The Express Rail Link (XRL) will provide high-speed rail services from Hong Kong to Guangzhou and a connection to the national high-speed passenger rail network serving major cities throughout Mainland, China. The HK$ 67 B (NZ$ 11.5 Billion) project is of great strategic importance for Hong Kong and is being implemented to a very tight schedule, from early 2010 with completion targeted for 2015.The works include a 15 platform terminus station in West Kowloon, 26 km of twin track tunnels from the terminus to the Hong Kong/Shenzhen boundary at Mai Po, tunnel vent shafts/adits/emergency rescue siding and a stabling siding facility. Trains on the Hong Kong section are intended to operate at speed up to 200 km per hour and up to 350 km per hour on the Mainland section.This presentation will provide an overview of the entire XRL project, with a focus on the challenging geotechnical and spatial constraints on the tunnel works. This is an abstract only. No paper was prepared for this abstract.

Mar 8, 2011

In an industry that is data-hungry and increasingly international in its outlook, the role of the New Zealand Government in facilitating exploration and mining activity here presents unique challenges. All things being equal, the Regime itself should result in æefficient outcomesÆ, however central to this rational economic tenet are the assumptions that the regime is in keeping with the times, other legislation works in tandem with it, and that those who administer the regime have the knowledge and experience to apply the rules wisely. Following the Crown Minerals review in late 2003, a shift in emphasis from Crown Minerals æmanaging the ActÆ towards proactively æmanaging the mineral estateÆ for greater benefit for all New Zealanders means that these assumptions are being increasingly challenged and addressed through a variety of initiatives. These include improved access to relevant data sets, minimisation of red tape and compliance costs, increasing emphasis on permit holder compliance with work programme obligations, changes to the Minerals Programme and regulations, closer collaboration with and representation to other government departments and councils, and additional recruitment of industry-experienced staff. This presentation will highlight aspects of these initiatives, and examine how they will collectively contribute to facilitating future exploration and mining activity in New Zealand.

Jan 1, 2004

Equity finance provides the most suitable and frequently the only access to capital during the exploration and evaluation stages of resource projects when project risk is at its highest. Investors are prepared to provide equity funds in the knowledge that they are compensated for the higher risk they take on with higher potential returns or sufficient upside potential to justify the higher risk. The context of resource projects which determines the role of equity finance has changed considerably. Prior to the resurgence of the gold price and the development of new mining technology many resource projects were selectively mining orebodies by underground methods frequently with limited reserves proved up in advance of mining. The limited proved ore reserves base and the volatility of the gold price all contributed to a higher risk and higher return investment environment in which the use of equity finance was more appropriate and frequently the only option for capital raising. The financial risk of a resources project can be transferred to an underwriter who makes the commitment to distribute the financial risk between a number of investors. There is also the opportunity for financiers to use a mix of equity and debt finance to allow a company to proceed with the development stage where without such a mix the resource project would not proceed. By using a level of equity finance the project becomes robust enough in its ability to service the debt finance facility and the project proceeds with the equity participants receiving a suitable risk reward return. The liquidity from the establishment of a market for the company's securities enhances further capital raising and generally enables the company to satisfy its financial requirements on more favourable terms particularly during bull markets. The role of equity finance in the management of the financial risk during the exploration, evaluation, development and mining stages of resource projects is summarised in Table 1. In more detail the principal roles of equity finance and the ways in which equity finance impact on the risk management of resource projects will be considered in turn.

Jan 1, 1994

The increased cost of imported oil fuels, coupled with our understandable reluctance to commit ourselves to the use of nuclear energy, has resulted in a renewed reliance on coal as a primary source of energy. New Zealand is fortunate in being fairly well endowed in its coal resources, but their exploitation until now, has been on a relatively small scale. Future exploitation, whether from underground or open cast mines, must be on a very much larger scale. This paper outlines some of the factors which should be considered in planning large open cast mines.

Jan 1, 1976

Site specific geotechnical data, deposit characteristics and method of mining are key factors when assessing an appropriate slope design philosophy. Mining geotechnics should be viewed as an iterative design process linked closely with mine planning, development and operational safety constraints. This case study presents geotechnical investigations for slope design at Macraes Flat Gold Mine using kinematic, probabilistic and economic analyses tempered with knowledge of site specific conditions. The recommended designs not only reduce early waste stripping tonnages but also provide data to optimise final walls.

Jan 1, 1992

By J Walasiak

In the climate planning of mines and tunnelling with anticipated poor climatic conditions, and especially in case of longer working shifts, the main question is whether it can be reliably prevented that certain climatic limits laid down be exceeded. Working at high temperature and/or humidity can lead to reduced human working energy û a very important economic aspect û and to a risky lack of concentration on the part of the miners or to heat collapse and extremely dangerous heat stroke. With the Deutsche Montan Technologie GmbH (DMT) climate prediction programs, both the dry and the extremely significant humid heat transfer can be calculated. This is due to the high planning reliability involved. With the help of these climate prediction programs it is already possible to determine the anticipated climatic values for the operation phase as early as the planning stage of new ore or coal fields or of tunnel construction projects and to design the optimum air cooling system for every underground project with due regard to technical and economic aspects.

Jan 1, 2005

By M Wilkes, C-Q Liu

Microbial oxidation of refractory sulphide ores (particularly gold and copper ores) are well-established techniques that are increasingly employed because of their low capital and operating costs and environmental benefits. CSIRO has established a multidivisional project, the æBioMineral Processing InitiativeÆ, with the goal of generating new and improved high temperature micro-organisms for biological oxidation of these refractory ores. The project is currently focused on the discovery/generation of novel hyperthermophiles for the bioleaching of copper from chalcopyrite. As part of this project we are investigating the practicalities of genetic modification of iron/sulphur oxidising micro-organisms. The molecular biology of iron/sulphur oxidising acidophiles is still in its infancy. This work is aimed at improving our knowledge of vectors, promoters, selectable markers, gene transfer and expression in these organisms. The Acidithiobacillus ferrooxidans genome is currently available and genomics is proceeding at a rate where in the next few years we can expect at least one or two relevant microbial genomes to be sequenced each year. New genes that impart useful characteristics to iron/sulphur oxidising acidophiles will be available from published genomes and the study of newly isolated hyperthermophiles. We need to be in a position to clone and express those genes. This paper will describe the isolation, transfer and expression of thiocyanate hydrolase genes in Escherichia coli and At. ferrooxidans. Most common antibiotics are not effective against iron/sulphur oxidising acidophiles. Also, the use of antibiotics or their resistance markers outside of a laboratory setting would not be appropriate. Resistance to thiocyanate should be a useful selectable marker, without implications for human or animal health. Additionally, thiocyanate resistant iron/sulphur oxidising acidophiles might have application in gold bio-oxidation plants in arid areas where reuse of contaminated tailings water is desirable. The cloning of thiocyanate genes in broad host range plasmids under the control of E. coli and At. ferrooxidans promoters and the expression and phenotypic effects in both species will be described.

Jan 1, 2002