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By R Tweedie

'The politics of mining in New Zealand' is a topic I chose myself because of its importance in the future of the New Zealand mining industry. There are many people in the industry who are cynical about politics, cynical about politicians and definitely cynical and often critical of political decisions. In fact, many industry people say they don't want to get involved in politics, they just want to get on with the business of exploration or mining. The point of my address is that politics is important and the industry cannot afford not to participate in the political process.

Jan 1, 1991

There is a lack of information concerning the movements of water on the continental shelf, particularly with regard to data obtained regularly over significant periods of time. The Horace Lamb Centre for Oceanographic Research has recently deployed data acquisition systems on the sea bed off the coast of South Australia to record tides, swell, and ocean temperatures. Some of these early records are described. The swell data are pertinent to future offshore operations with drilling rigs, barges, and other equipment, while the temperature variations give evidence of significant bottom currents, apart from those due to swell.

Jan 1, 1971

Effective Dry Density Benefication of Coal

Sep 13, 2010

An investigation into the causes of variable sulphur content in blast furnace metal produced at No. 4 blast furnace at the Port Kembla works of Australian Iron and Steel Pty. Ltd. was carried out. Theprogramme included an extended and detailed experimental study of a great number of the operating variables of the furnace, on a cast-bycast or four-hourly basis, over fourteen days.Possible causes of the variation were found in irregular operation due to sinter variability, and it was also clearly shown that slag conditions were most important in controlling sulphur contents of pigiron. Some decrease in sulphur variability was achieved, arising partly from this investigation, and it is hoped to try magnesia additions to modify slag conditions for better desulphurizing.INTRODUCTIONSulphur in pig iron is a problem common to many blast furnace operators throughout the world, but the direct causes and means of overcoming them are functions of the available raw materials, and are hence more particular to each plant and its operating practice. Sulphur in hot metal influences the steel-making operations, the rolling operations and the quality of the finished steel. The main problem associated with high sulphur in steel is "hot shortness", which leads to cracking of ingots and billets in rolling, to poor surface finish and to poor welding properties in the finished steel. On the other hand, sulphur is sometimes a desired additive to steel in order to promote free machining properties.Normal means of controlling sulphur A small degree of control of sulphur in steel is available to open hearth operators by alteration of slag volumes and basicity, but any large degree' of sulphur elimination is...

Jan 1, 1961

Minerals processing needs a step change in energy efficiency. While the search for new technology breakthroughs is important, huge gains are still available by better using existing research outcomes. This potential remains untapped due to a combination of organisational 'silos', inappropriate performance measurement, and poor science in some areas. It is time to see the elephant in the mill.

Sep 13, 2010

Ultrasonic Extinction for High Resolution Particle Size and Concentration Analysis

Sep 13, 2010

By A Liu, T Ren

Gas explosion in underground coal workings can pose a serious threat to the safety of mine workers and the entire mine operations. Gas explosion is a very complex thermal-chain reaction in a confined underground environment. Based on combustion and explosion theory, three dimensional (3D) computational models were developed to simulate mine gas explosion flame and overpressure wave propagation in a single entry gateroad in underground coalmines. Six different explosion scenarios were modelled and compared with large scale experimental results and AutoReaGas simulations. Model validations show that the use of shear-stress transport (SST) k-? model together with eddy-dissipation model (EDM) produces good agreement with both experimental and AutoReagas simulation results. Modelling results demonstrated that the changes of temperature versus time can be divided into four stages, ie the initial condition stage, and periods of warm-up, active burning, and burnt-out. Assuming a limited volume of methane is involved in the explosion, the maximum temperature decreases as the distance increases from the explosion point, with the highest temperature reaching about 2460 K. Modelling results show that the evolution of the explosion flame shape experiences four typical stages, ie spherical flame, finger-shape flame, flame with the skirt touching the side walls (ribs) and tulip flame, which are similar to the pattern of a duct explosion. The pressure in the gateroad remains the same as the initial value before the arrival of the explosion wave and then increases rapidly to the maximum value. Modelling results from this study will be used for the design of explosion arresting devices and mine seals in underground coalmines.CITATION:Liu, A and Ren, T, 2017. Computational simulation of gas explosion and its propagation in single entry gateroad, in Proceedings Australian Mine Vent Conference 2017, pp 181–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

This modern plant was installed with the object of treating all oxide ore and payable dump material by the cyanide process.The plant is located on a ridge on the eastern side of Linda Gully. The mill -site has a slope to the south of 1 in 4.The new plant is of steel and concrete construction and was specially designed to suit the climatic conditions which exist at Mount Morgan.THE COARSE CRUSHING PLANTThe ore received from the, mine is dumped into a 600-ton steel bin which is commanded by a 3 ft. 6 in. gauge railway,The mine ore is conveyed by steam locomotives in rakes of five self-dumping 7-ton railroad cars. The dump material is mostly loaded by bull-dozers and conveyed to the binsin large motor lorries. Located on the top of the bin is a heavy railroad grizzly having 12-in openings through which all ore must pass.The flow of ore from this steel bin is controlled by a No. 7D 3-speed Ross chain feeder. It should be mentioned here that, although the bottom of the steel bin is inclined at an angle of 45°, it has been found, owing to the clayey nature of the oxide ore, that the live capacity of the bin is only about 50% of the total capacity.

Jan 1, 1939

The principal dirnensions of the chimney were fixed as follows: Height from formation to coping, 328 ft. 8 in.; inside diameter concrete shell, 13 ft. Gin.; inside diameter of the 4~-in. brick lining. 11 ft. (j in. ; shell thickness above flue inlet at a point 39 ft. above formation, 1 ft. 8in.; shell thickness at coping, 6 in. That is, the inside of chimney is cylindrical, wldst the outside is gradually stepped inwards with of 1 in. and less until the shell is 6 in. thick only at the top. With these dimensions in mind, it will be seen that some close thought was necessary to ensure a satisfactory of fonn which could be kept rigid and plumb to a height and at the same time provide safe working conditions for the labourers employed.FOUNDATIONSThe spread base of the chimney is 45 ft. in diameter, and foundations were carried down to a depth of 8 ft. 6 in. below natural surface into good hard clay which was known to be the best foundation obtainable in the vicinity being capable of withstanding, when dry, a load of 3 tons to 4 tons per square foot, whereas dead load is 1A tons per square foot and the maximum load expeeted under the most severe wind condition is 2 tons per square foot to ensure the foundation being kept dry and unaffected by ground water, the site was surrounded by a ring drain at a distance of six feet from edge of concrete foundation and at a minimum depth of one foot below bottom of concrete. Open-jointed pipes were laid in the bottom ofthe drain and graded to a pipe drain with outfall clear of the site.

Jan 1, 1924

Development of Cost-Efficient Environmentally Sound Technology for Enhanced Gold Recovery from Rebellious Gold-Containing Raw Materials Study of biochemical leaching performances in gold-bearing sulfide minerals processing enabled to develop environmentally sound technology of enhanced gold recovery from rebellious gold-containing raw materials. It was found that the ?-10 IMO bacteria activity contributes to increasing system oxygen concentrations and incrementing in rates of oxygen delivery onto surface of gold-bearing minerals. Bacteria activity products, ie, amino acids (?), support the formation of such heterocomplexes as [A-Au-CN]- , providing additional gold recovery into solutions. Technological properties of proposed bacteria solutions were studied. It was found that the proposed bacteria inoculants are capable to growing directly in process of raw materials leaching within a large pH range of media containing cyanides and thiosulfates. They oxidise the sulfur to the sulfate, as well as the antimony (III) and arsenic (III) sulfides to the pentads. For the first time, the hydrophobic cell properties, metabolites emulsifying efficiency, adsorption properties, wetting ability, surface tension and electro-kinetic potential of new bacteria strain solutions were studied as compared with chemical solutions. It was found that the proposed bacteria inoculants reduce surface tension at the solvent-mineral and solvent-concentrate phase boundaries. All aforementioned effects enhance mass transfer processes efficiency. IR-spectroscopy of new bacteria strain culture liquid allowed identifying available amino acids which substantially contribute to heterocomplex anion [A-Au-CN]- formation. Active involvement of heterotrophic bacteria in gold dissolving processes was identified. It was shown that the structure of metals complexes is substantially modified at intensive pulp agitation and during long-term storage. Fractional order reaction in biochemical and chemical gold leaching was identified. It evidences that the gold and impurity metals dissolving processes advance in synchronism. The both processes are running in diffusion zone. Biochemical leaching has advantages over chemical leaching, ie it provides enhanced rates of precious metals dissolving, improved gold recovery by 20 - 30 per cent, decreased cyanide consumption by 50 per cent. At the same time it allows to decontaminate dangerous substances contained in productive solutions produced in rebellious gold-containing raw materials processing. Basic parameters of flotation concentrates leaching by heterotrophic bacteria-assisted processing technology were tried and tested. Technology of gold sorption from leaching solutions was successfully tested.

Sep 13, 2010

By D Craw, D Wilson, D Chappell

Gold is extracted by cyanidation of a sulphide-rich concentrate at Macraes mine, and after cyanidation, the concentrate is discharged to tailings impoundments. The concentrate tailings were discharged to a dedicated concentrate impoundment from 1989 to 1993, afterwhich they were blended with the flotation tailings. Since mid-1998, concentrate tailings have been redirected to the dedicated concentrate impoundment. The concentrate tailings contain up to 1 ppm gold, and will be reprocessed in the future. However, it is a regulatory requirement that a contingency plan be in place to rehabilitate the concentrate tailings should the mine operation cease for any reason. Initial predictions suggested that the sulphide-rich tailings would oxidise and acidify, creating a potential long term environmental problem. Investigations of the state of the tailings after 4 years show that these predictions were overly conservative. Only minor oxidation has occurred in the upper 2 metres of the tailings where the pH has locally dropped from 10 (discharge condition) to between 7 and 8. Below 2 metres, the tailings are essentially unchanged from their deposition state. The low rate of change in the tailings is due to their very low permeability which in turn is a consequence of the fine grain size (ca. 15 ¦m). Dewatering is extremely slow, and incursion of oxygenated water is negligible. Calculations suggest that water movement over 30 m will take at least 100 years and possibly 1000 years. The contingency plan is to capitalise on the very low permeability and keep the tailings from drying with a semipermeable cap. A layer of limestone will be added to the top of the tailings, beneath the cap, to enhance alkalinity of any percolating water. If acidification does occur, contrary to expectations, any acid produced will be neutralised by underlying calcite-bearing schist, schist in the concentrate impoundment wall, and the flotation tailings immediately downstream. In addition, dilution by alkaline ground and surface waters would further ameliorate any acidic discharge.

Jan 1, 1998

By L Langer, R Simcock, M Davis

Rehabilitation of mining sites helps to achieve the purpose 5(2c) of The Resource Management Act 1991 û æavoiding, remedying, or mitigating any adverse effects of activities on the environmentÆ. The environmental outcomes for recent and current mining operations on the West Coast are variable. There are some exemplary mining operations which are restoring or even improving land use and environmental factors in the region, particularly those operated by the larger mining companies. There are also examples of an exploitative mentality where the environment and land have been severely degraded by mining activities. Technology has been developed to prevent a repetition of the historical destruction of the environment through mining. Failure to rehabilitate mined land is no longer acceptable to the New Zealand public in the 1990s and damages the credibility of the mining industry. Examples of successful mine site rehabilitation to pastoral farming and to production or plantation forestry are illustrated from the alluvial gold mining industry. Planning, sequencing of operations, the utilization of sailor plant growth materials, and aftercare are key factors in successful land rehabilitation to these productive uses. There is also a recent focus on restoring indigenous forests and wetlands at both coal and gold mining sites, particularly for mines on or adjacent to the conservation estate. The results of scientific research and efforts by the industry on techniques for rehabilitating rainforest and pakihi wetland after mining are presented, particularly from the Giles Creek Dunoille Coal Mine. There is a need for further research and trials to apply and extend rehabilitation techniques to other geological and environmental situations, particularly to mines in mountainous areas and to difficult environments like the coal measures ecosystems of the plateaux above Westport.

Jan 1, 1996

By S Vianna, K Caldwell, R Silva, T Olson, D Bell

Studies to enhance the FLSmidth forced air machine through changes in the design, showed important improvements through changes in the number of Rotor blades, stator designs, rotor air distribution and other designs features. The main outcomes from this study highlighted that increasing the number of rotor blades increased the selectivity while decreasing power requirements while stators with slots have better results in terms of recovery, flotation efficiency and selectivity than without slots.Also the rotor air distribution makes a difference in the design when comparing different distribution criteria whilst keeping all features of shape and number of blades etc constant. At the most efficient rotor air distribution design, copper recovery reached one of the highest values while keeping good selectivity. The possible explanation for that is the increase in the pump capacity indicated by the increase in the specific power.It was seen as significant that reduction in specific power for some designs tested compared with the then current standard design had an average of 30% less power consumption.As a result, FLSmidth was able to identify new designs that decreased power and improved recovery, as well as, identifying some designs that specifically improved fine and/or coarse particle recovery.CITATION:Silva, R, Caldwell, K, Bell, D, Olson, T and Vianna, S, 2013. FLSmidth flotation developments - Dorr Oliver machines, in Proceedings MetPlant 2013 , pp 413-430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

The object of this paper is to give a description of the new office and changehouse building and equipment at the Zinc Corporation Limited, the office section of which has now been in full use for approximately three years, and the changehouse section for approximately two years. As the expectations of the design have been fully realized, it is thought that this description will be of interest to members and possibly of some use to others faced with similar problems.GENERALIn the centralization of the surface plant around the new main shaft the combined office and changehouse building forms a prominent feature, being located between the shaft and the mill and facing the workshops on the northern side.The scheme for housing all employees in one building was proposed by the Manager, Mr. A. J. Keast, who was familiar with a similar successful structure built at the McIntyre Porcupine Mines Ltd. in Ontario, Canada.The principal features of this building were adopted as a basis for design, and the present layout evolved to suit the particular requirements of this mine.Some of the advantages of the design are:(a) Economy in first cost and space occupied when compared with plants having separate office and changehouse buildings.(b) Easier and more constant supervision of employees and of the plant by the senior staff members.(c) Close contact between officials of all departments.(d) Close covered connection between changehouse and shaft.(e) Avoidance of duplication of ,essential services such as electric power, water, heating plant, sewerage, etc.The Managing Director, Mr. W. S. Robinson, further instructed that the following requirements be adhered to in the new building:(a) Ample accommodation to be provided for office staff and other employees.(b) Special attention to be paid to lighting, both natural and artificial.(c) Working temperatures to be controlled to facilitate comfort and efficiency.(d) The buildings and equipment' to be of a permanent nature with furnishings and fittings of modern design.

Jan 1, 1941

An Ammonia Leaching-Solvent Extraction-Electrowinning-Flotation Process for Copper Oxidised Ore Treatment

Sep 13, 2010

By S C. Dominy

Various styles of gold mineralisation pose problems during sampling because of their complex gold grade distribution and presence of coarse gold. Effective sampling and sample preparation forms the basis of resource estimates. The design of a sampling and assaying protocol must be based on a thorough understanding of the mineralisation in question, which should include consideration of gold particle size and mass distribution. The proportion of coarse gold within samples has a profound effect on the requirements for sample preparation and assaying. Choice of preparation procedure and assay type is of critical importance if sampling errors are to be minimised. Traditional fire assays, using small charge sizes, often understate assays gained from large charge sizes and techniques such as screen fire assay and LeachWELL. Proper application of the Theory of Sampling reduces errors during collection, preparation and assaying. A quality control/quality assurance program must be implemented and critically assessed. A case study from the Ballarat mine is presented, which is characterised by substantial quantities of coarse-gold hosted in quartz veins. Diamond core drilling is the key input into resource delineation. A number of different sampling and assay options have been trialled over the recent project history. The current sampling protocol utilises whole drill core, using LeachWELL assays after logging and photography.CITATION:Dominy, S C, 2017. Sampling coarse gold-bearing mineralisation – developing effective protocols and a case study from the Ballarat mine, Australia, in Proceedings Eighth World Conference on Sampling and Blending , pp 71–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By S J. Loach

Geological reconciliation is an indispensable part of BHP Billiton’s Western Australian Iron Ore (WAIO) operations. Since 2009 our reconciliations have been calculated in a single, centralised sequel-server database. This system draws data from across our operations and calculates a hierarchical sequence of reconciliation factors that span the company from the smallest grade control (GC) block to the whole of WAIO. It then presents the results using sophisticated graphical reporting tools.The initial motive for developing WAIO’s reconciliation system was to meet corporate compliance and public reporting requirements. The ability to validate our resource and reserve models by comparing their estimates of tonnes and grade with production figures remains the system’s principal function; however, as the system has matured, we have significantly developed its ability to support the improvement of various technical activities within the business. For example, the system can now calculate and report reconciliation factors for different resource classifications, short-term planning models and geometallurgical estimates.More recently, great emphasis has fallen on the system’s ability to detect and warn of possible geological issues that may pose a risk to either production schedules or product quality. We envisage a future where automated analysis of our large historical data set will enable high-risk conditions within future mine plans to be detected and highlighted.In all of these ways geological reconciliation plays an important role in contributing to this company’s financial and operational resilience.CITATION:Loach, S J, 2017. The development and future of BHP Billiton’s Western Australian iron ore geological reconciliation system, in Proceedings Iron Ore 2017, pp 415–422 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Rational decision making is generally perceived by managers of operations to be a delicate process of committing large sums of money and putting other people's life at risk. Consequently most managers may argue that the decision process requires good judgement, intuition and extreme caution; and not one easily made through the use of fancy mathematical algorithms and computer programs. The advent of artificial intelligence and expert systems in the computer industry combined with recent technological innovations in mathematical and economic problem solving is sure to change this perception. PARETO OPTIMALITY is an economic and a mathematical optimisation concept applied to solving real life operational problems; and one that the current volatile economic forces would require managers to employ because it is virtually real. REALISMM is a computer software package developed using the principles of Pareto optimality, dynamic programming, optimal clustering of information and decision maker interaction to generate decision maker preferred solutions. REALISMM has scope for artificial intelligence and expert systems application for cases where the decision maker is unsure about his objective preferences.

Jan 1, 1993

Mining Systems and Technology - Synchronous Electric Drives for Grinding Mills

Sep 13, 2010

By Lyman G. J

Dense medium drum separator efficiency was analysed at two Western Australian iron ore concentrators. Efficiency data had hitherto been difficult to accumulate due to the high cost of analysing representative, and therefore large, coarse ore samples. To overcome this problem, recoverable density tracers, which are in effect artificial mineral and gangue, were manufactured in three different sizes (15 mm, 30 mm and 60 mm). Their use enabled partition curves to be studied within one hour of conducting a test: separation densities were generally lower than the feed medium density for all three sizes of density tracer. For a given set of operating conditions, the smaller tracers had lower separation densities and larger ecart probab/es than the large tracers. These phenomena are explained with the aid of a conceptual model of a drum separator, which assumes that the feed ore plunges to the bottom of the drum upon introduction. Particle rising velocities are, therefore, process determining.Medium rheology was altered by adjusting the proportion of solids in the pulp. This was accomplished by changing both the pulp density and ferrosilicon/magnetite ratio. Higher solids volume fractions invariably caused a decrease in separation densities and an increase in ecart probables, most markedly for the smaller tracers. A similar response was observed when feed tonnages were raised.An explanation for these phenomena is sought in the discussion which also suggests means of improving drum separator efficiency.

Jan 1, 1987