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Coal mining in New Zealand is principally a State-owned and controlled operation where the State produces 70 per cent of the coal in New Zealand and 65 per cent of coal mined in the Waikato. The State's flexibility in production quality and price makes them tough competition. Coal in the Waikato varies in quality considerably throughout the region making the high quality coal deposits as in the Huntly district a highly sought after commodity. The high quality of coal is often offset against transport costs as, for example, Maramarua coals can compete effectively in the Auckland market and dollar per calorific value basis.

Jan 1, 1984

Engineering education has become a matter of national concern, at last, so I would like to talk about the links between the mining industry, the universities and technological developments. The Australasian mining industry and the mining schools have collaborated closely since the first school was established in 1871 and during those years there were a series of remarkable technological developments. For example:In the late 1880s George AndersoIl Richard developed chloride leaching of gold at Mt Morgan. This made a large difference to the wealth of Mt Morgan Mining Ltd.In the mid 1890s Robert Sticht demonstrated that pyrite smelting was an economically feasible process at Mt Lyell and the wealth which came to Mt Lyell Mining Co from his outstanding work made it one of the great companies in the country.During the first 15 years of this century flotation was developed at Broken Hill and it has proved to be one of the great technological inventions of this century.In the 1920s G K Williams started his outstanding work on lead smelting and refining at Port Pirie, this was work which ultimately re-wrote the text book on lead metallurgy and established Port Pirie as the mecca for lead metallurgists.In the 1920s also Frank Stillwell, later joined by Austin Edwards, established the new science of mineragraphy at the University of Melbourne. They were both great geologists, both were superb scientists and oddly enough both were outstanding athletes.In the 1930s Dr Ian Wark, a man in the front rank of Australian scientists of any period, started his outstanding work on flotation, work which resulted in a text book which remains a leader in its field today.In the 1930s also Arnold Black at Broken Hill South Ltd picked up the work which had been done at Mt Lyell many years previously and eventually wrote the papers on hydraulic fill which demonstrated that he led the world in fill technology. What a remarkable story of achievement it was, it laid the groundwork for the great industry we have today. It was possible because the industry was well supported by outstanding university schools and I would like to talk about some of these.

Jan 1, 1989

Underground equipment owners and users in order to compete and succeed in being viable business propositions must continually balance costs with productivity. By reducing their hourly ownership, operation and maintenance costs and increasing their hourly production, the cost per unit of material mined will be optimized.

Jan 1, 1990

Judicious placement of a range of geotechnical instruments was employed at the Tasmania gold mine, Beaconsfield, Tasmania, as a key strategy in the monitoring of rock mass conditions over the past four years. The range of instruments employed included vibrating wire stress-meters and hollow inclusion cells to monitor changing stress conditions, resistance wire and multipoint borehole extensometers to monitor the impact of stress changes on the integrity of the rock mass, and instrumented cable bolts and threadbar bolts to monitor the static and dynamic impact of rock mass changes on the installed ground control system. Initially the monitoring was of a qualitative nature, monitoring change from the time of installation. The value of the output was considerable when considered in relation to the ongoing seismic record which was also being monitored. It was clear from the seismic record and the monitoring results that stope blasting was the primary trigger for changing rock mass conditions. However, it was unclear how well observed behaviour was reflecting conditions anticipated by elastic numerical modelling. The latter had predicted significant stress increase in the near field of man-access footwall development. Qualitative monitoring and visual inspection did not support the modelling prediction, and this led to a program of quantitative measurement being undertaken. Measurement of the absolute stress condition in the backs of footwall development immediately adjacent to monitoring hollow inclusion cells provided the benchmark for tracking quantitative stress change. The program provided insight into the evolution of principal stress field magnitude and orientation in relation to rock mass change observed with extensometers and instrumented ground control elements, as well as providing a degree of calibration between the elastic numerical modelling and the virgin stress field. Calibrated monitoring data has also provided a useful benchmark for finite element modelling which is to be used for future mine-wide design.

Nov 25, 2010

In the geologically prospective nations which rim the Pacific Ocean, mineral deposits offer great potential to create wealth for social and economic development. The paper first examines the geological and economic attributes of potential mineral wealth based on current outlook assessment of all significant base metal deposits discovered to 1988 in two Pacific Rim nations - Australia and Canada . The variability of mineral wealth among the economic deposits evaluated and the major contribution of the few world-class discoveries to total mineral wealth are highlighted. Then, the essential but too often neglected linkage between the makeup of potential wealth and its actual realization is analysed. The impact of taxation and the role of exploration are crucial in this regard. Finally, the ingredients of exploration success, prerequisites for realizing the mineral wealth of nations, are examined.

Jan 1, 1995

Considerable improvements in diamond drilling equipment have been made since the early 1950s. A recent drilling programme, however, at Williamtown, near Newcastle, carried out by the Joint Coal Board on behalf of the Electricity Commission of New South Wales, emphasized deficiencies in existing equipment when particularly diflkult coring conditions were encountered.Spurred by unacceptably low recoveries in coal seams in this area, the Joint Coal Board devised and developed, with the assistance of the Electricitv Commission, a new typc core lifter and a special 26 ft triple tube core barrel, designed to operate in conjunction with it in bad coring conditions.The core lifter, whieh is propped open clear of incoming core during drilling, is activated by fluid impulses generated inside the core barrel. It can be used with double tube barrels when drilling firm rocks whichdo not change diameter by compaction inside the barrel.Softer rocks. such as clayey types, require the use of a rriple tube barrel.Results from testing carried out to date in difficult areas in New South Wales coalfields have shown that greatly improved results can be obtained with the new equipment. Although developed essentially for coaldrilling, the new core lifter and barrel could be adapted to other fields of diamond drilling. Even in areas where no great coring difficulty is encountered the cost advantage deriving from the greatly inereased life of the core lifter and the adaptor in which it is housed could justify its use.

Jan 1, 1967

By V Chamberlain, M Appeah Owusu, M Aniawu-Asumakah, A Anyimadu, R Peattie

This is an integrated geology and plant improvement study arising from the heterogeneity seen in mineralogy and gold association at the Obuasi goldmine in Ghana. This heterogeneity comes from the two ore types mined, the one being a sulphide ore, mainly composed of gold-bearing arsenopyrites. This gold is refractory and exhibits a strong relationship between gold and As. The other is quartz veins, that are high grade and free milling. The installed circuit consists of comminution – Gravity -Flotation – BIOX – Leaching and Adsorption processes. The opportunity tested involved improved mass pull - related flotation recovery of Au in the Sulphide stream; while balancing the need for a minimum Sulphide grade for the Bio-oxidation process, occasioned by the removal of 25 to 30 % of the (quartz) stream through preconcentration by Ore sorting. The current circuit is then utilized for the sulphide route, while a smaller grind-gravity circuit is utilised for the quartz stream in a relatively inexpensive way, followed by a common leaching and adsorption circuit. Added advantages of the strategy includes faster recovery of gold from the quartz stream, with less consumption of reagents from saving on flotation and BIOX reagents for this stream. Screening and Ore sorting was successfully tested with laser technology, achieving over 98% separation of quarts (containing up to 40% of the gold). The plant schedule of Ore, the suggested circuit design for the Ore sorting, the results obtained from the different flotation regimes, as well as consequent financial modelling have been presented and discussed in this paper. This illustrates the opportunity that arises out of a detailed analysis of material versus installed circuits, even if the gains in pre-concentration do not necessarily involve rejection of gangue material. An added opportunity for future investigation, briefly discussed but not tested in this paper, would be to maintain current mass pulls but with increase in throughput (by the space created by the sorted material). This will of course require the mining ability. It could also add LOM value by altering the cut-off grade.

Nov 10, 2020

By C Garrido, J Barrera, H Alvarez, L Perez, S Ramirez

In recent years, there has had a greater recurrence of studies and projects that consider tailings filtration followed by dry stacking to reduce the consumption of fresh water, the space required for disposal, and, eventually, to reduce the costs of the project. In addition, this technique could be required to meet new environmental restrictions to extend the life-of-mine of existing plants or to enable the development of new projects, especially in areas of high social interest. This article is intended to describe the most relevant technical aspects of the design and implementation of an iron ore tailings filtering system and its final overland disposal as well as physical and metallurgical surveys, and laboratory and pilot testing. Furthermore, it is presented how these activities are inserted in the project development to rationalise the resources. The case under study considers an iron mineral wet magnetic concentration processing plant. The outcome tailings are dewatered by means of thickeners, where the overflow water is recycled back to the plant. The underflow slurry is pumped into intermediate storage tanks before proceeding with further dewatering and final disposal. The project consists of a tailings filtration plant, belt conveying systems, a temporary stockpiling system, trucking loading and transportation system, moisture-conditioning facilities (spreading and airing), and final disposal facilities (compacting). Due to the stickiness of the filtered tailings that governs the belt conveying system design, the operating moisture range must be established. Besides, proper technical aspects such as planning, executing, and analysing both the laboratory and the pilot testing data to validate process design parameters; selecting filters; defining spare filtering capacity; handling the out-of-range filtrated moisture; sizing the belt conveying system; configuring the equipment involved, must be considered.

Nov 8, 2021

A rotating disc geometry was used to provide a uniformly accessible surface for a kinetic study of copper cementation with zinc in sulphate solution. For copper concentrations of the order of 10 p.p.m., a porous, adherent deposit is formed on the zinc surface and this has a significant influence on the reaction rate. When the specific mass of deposit is less than about O· 35 mg/cm2 the surface may be considered as smooth and the rate is described by simple convective counter diffusion of zinc and copper ions through a laminar diffusion boundary layer to the deposit-solution interface. In the presence of additional deposit, the diffusional mass transfer rate is increased by increased surface roughness.The rate under these conditions is first order, with the degree of enhancement independent of further increases in the specific deposit mass. The enhancement in rateis, however, directly related to the initial mass flux and the species involved in the reaction.Preliminary work showed the same mechanism to apply to cementation from chloride solution, solutions of high zinc concentration, and cementation of copper with iron..

Jan 1, 1970

By R Peden

Recent, detailed mapping, (Allibone, 1986; Peden, in prep.) of north west Stewart Island, has shown that the Rakeahua Granite (Watters et al, 1968), is comprised of a wide range of granitoid bodies ranging from diorite to leucogranite. As a result of the wide variation in granitoids Allibone (1986), suggests renaming of the Rakeahua Granite to the Rakeahua Granitoid Complex. Names were also proposed for the individual granitoid bodies mapped.

Jan 1, 1987

Gold rooms represent a high security area and preventing theft is a challenging task. Where gravity concentrates or high value unit intermediate products are present, particular and specific security procedures must be put in place. This paper describes the development and implementation which reflects best practice in gold room security. Procedures involving key holder systems, key locks, swipe cards and double locks preventing any one person having access to the gold room, including specific procedures for gravity gold concentrators, will be addressed. The use of monitoring and how to deal with alarms and potential hold ups will be reviewed. The use of cameras and archival DVD recorders is common in gold rooms. The use of electronic surveillance, movement detectors, seismic monitors and the two person policy and gold room entry procedures are described, including how to deal with visitors. The importance of confidentiality regarding smelting and gold pick-up days, plus strategies employed to minimise storing large quantities of gold on site will be presented. The role of metallurgical accounting in providing quality auditable information and the minimum standards of record keeping required is discussed. The role of the Gold Squad will be outlined. Regular auditing and risk analysis and several case studies are cited where security was deficient or improved.

Aug 1, 2010

By Arthur A. F, MacKenzie I. H

Copper in zinc/lead sinter charged to the Imperial Smelting Furnace operated by Sulphide Corporation Pty Limited at Cockle Creek, New South Wales, concentrates in a complex lead dross which forms as the bullion is cooled to around 400°C. The 0.35 mm portion of this dross, containing approximatelY 67 per cent of the total copper, is treated via a hydrometallurgical route to produce 5000 tonne/yr of CuSO4 5H2O crystal.Around 3000 tonne/yr of copper-lead dross containing 49 per cent copper is leached at 55°C in continuous leach reactors with ammoniacal ammonium carbonate leach liquors to convert copper to soluble copper amine complexes. Leach ettlciencies of 80-85 per cent are obtained. Leach residues are repulped with ammoniacal liquid diluents from the plant and heated in a four stage steam distillation unit to reduce ammonia levels to between 0.5 and 1.0 g/Iitre. The resultant slurry is directed to an effluent treatment plant for final treatment, and separation and return of solids to the sinter plant.Copper is extracted from leach liquor by solvent extraction techniques based on the use of L1X 54 diluted 3:1 with Shellsol 2046 to give a nominal copper loading of 30 g/litre. The loaded organic is contacted with a sulfuric acid solution of pH 5 to remove the bulk of ammonia and zinc, then stripped at 55°C with a 60 g/Iitre H2SO4 95 g/Iitre copper solution to yield a 15 g/Iitre H2SO4 125 g/Iitre copper solution.This liquor is fed to an adiabatic vacuum crvstalliser operating at 35°C and 5 kPa vacuum where crystals of CuSO4 5H2O are formed. Crystals are separated from mother liquor and washed in a two stage pusher centrifuge, then dried in a hot air rotary drier. The crystal product obtained is of a high chemical purity and readily conforms to both Australian and overseas standards.

Jan 1, 1983

By H R. Phillips

During the 1980s and early 1990s, the South African coal industry experienced a series of methane explosions in which well over 200 coal miners lost their lives. In addition, a fire and an explosion in the gold mining sector claimed a further 240 lives. These tragic incidents resulted in the establishment of a research facility at Kloppersbos dedicated to explosion and fires research and the funding of an extensive research program, and almost certainly influenced the government of the day in its decision to establish, in 1993, the Leon Commission of Enquiry into Mine Health and Safety. The results of this focused research program, the wide-ranging recommendations of the Leon Commission and the determination of the coal mining industry to improve its safety record all combined to result in the past 20 years without a major explosion.This paper lists some of the research outcomes and, through three case studies, illustrates what can be learnt from investigations following explosions. The paper concludes with an evaluation of some of the findings of the Royal Commission on the Pike River coal tragedy. Many of the Commission’s conclusions are pertinent and relevant to the coal mining industry worldwide and their implementation could significantly improve coalmine safety; however, a careful study of the available facts indicates there could well be an alternative explanation of the source of the methane, the location of the ignition and the size of the explosion at the Pike River coalmine.CITATION:Phillips, H R, 2015. Lessons learnt from mine explosions, in Proceedings The Australian Mine Ventilation Conference, pp 19–28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By T Atchison

The Vale Ferro Carajßs S11D project in northern Brazil is based on the movement of unprecedented volumes of waste and ore for mobile in-pit crushing and conveying or ætrucklessÆ systems. In peak years, the system is intended to handle a combined 160 Mt of material.The planning and implementation of the first such system for Vale, in a remote greenfield site, utilising the services of a range of international study, design and supply partners has provided a unique set of technical and project delivery challenges. The lessons from these are of value to the industry as the trend to remote and high-volume operations continues.This paper describes the key features of the mining system and documents the challenges and mitigations for important technical, cultural and project delivery issues that have arisen. It is a combined description of the journey taken by both Vale (as owner) and SKM (as delivery partner) over the course of many years.CITATION:Atchison, T, 2013. Lessons from the S11D truckless mining project, in Proceedings Iron Ore 2013 , pp 177-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By D J. Woodward, A B. Christie, S A. Henrys

Low-level aeromagnetic data available in digital form have been combined to produce a new 1:100 000 scale map of total force anomalies of the Coromandel region, New Zealand. The map incorporates data from 13 surveys flown between 1977 and 1990 and shows the regional magnetic pattern as well as more detailed localised anomalies. In addition to magnetic anomalies, the map also depicts data to aid interpretation, including small-scale maps of topography, geology, magnetic intensity gradient and apparent magnetisation. The primary magnetic anomalies of the Coromandel region are associated with Late Miocene and Pliocene volcanic rocks, but have been locally modified by intense hydrothermal alteration caused by geothermal activity. Epithermal gold-silver and porphyry copper deposits are associated with zones of hydrothermal alteration. The map of magnetic anomalies can be used as an aid to mineral exploration and the interpretation of the processes that control the distribution of mineral deposits in the region.

Jan 1, 2001

The modern Golden Cross mine entered the production phase in January 1992. The project is designed to produce over 100 000 oz/yr of gold and over 300 000 oz/yr of silver during a mine life of eight years. An open pit and an underground mine are operated producing around 850 000 t/yr of ore, to feed a conventional carbon-in-leach processing plant. Golden Cross is owned in joint venture by Coeur Gold New Zealand Limited (80%) and Viking Mining Company Limited (20 %).   Since the start of production several major aspects of the design have altered. The underground mine began as a mechanised cut and fill operation. The cut and fill stoping progresses in 3.3 m flatback lifts with maximum stoping width of 6 m. Where the ore zone is wider than 6 m a post pillar cut and fill method is used. In 1993 a new bench mining plan was introduced between the 270 and 260 levels. Flatbacking continued in the footwall drives in anticipation of variability of the ore width and orientation. The development of levels below the main service 200 level has indicated a possibility of bulk mining the ore block rather than flatbacks. This could lower mining costs but also introduce higher dilution rates. Development is in the advanced stages for trialing this method.

Jan 1, 1994

Mr. Murray said: Having recently returned from a visit to America, it may be of interest to members to hear something from me of the mining fields and metallurgical works which I had the opportunity of seeing, and the impressions which I formed concerning general practice and conditions there, as compared with our Australian standards in the mining industry, and in matters generally.The most striking feature of the North American continent is thehuge plan upon which Nature has built, the multiplicity of immense mountains, rivers, and lakes, the snow-covered tops of the former forming reservoirs for the latter during the summer months, being most impressive to the Australian visitor. Starting from Vancouver I travelled east for over 500 miles through the wonderful Canadian...

Jan 1, 1927

By Edwards A. B

The occurrence of lollingite (FeAs2 ) in the Broken Hill lode is recorded by an analysis of lollingite published in the Annual Report of the Department of Mines, New South Wales, for the year 1934 (p. 69). The analysed specimen came from the North Broken Hill mine, and material from the same occurrence (Specimeh No. 1), as well as two specimens (Nos. 3 and 4) from the Zinc Corporation mine, have been forwarded· to us by Mr. M. Mawby of the Zinc Corporation Mine. This material has been supplemented by another specimen (No. 2) from the Zinc Corporation mine, passed over to us by Dr. I. Wark.The original analysis of lollingite is quoted in Table I, and shows that the Broken Hill lollingite contains appreciable amounts of cobalt and nickel, and, indicates that the iron is to a considerable extent replaced by cobalt and nickel, so that its formula should be written (FeCoNi) As2This is supported by a microscopical examination of a polished surface of the lollingite, in which no individual arsenides of cobalt and nickel can be detected.Coarse grained galena, sphalerite, chalcopyrite, and pyrite are attached to our specimen of lollingite from the North mine, and are separated by a sharp junction from a mass of lollingite associated with some arsenopyrite and garnet. The massive lollingite can be distinguished from arsenopyrite in the hand specimen by a much brighter, silvery lustre, against which arsenopyrite appears a dull silver grey; but the passage from lollingite to arsenopyrite appears transitional.

Jan 1, 1939

By E Kasai, T Nakamura, E Shibata

In the present study, formation of PCDD/Fs from carbon particles like æsootÆ, so called de novo synthesis, was experimentally simulated using the powder mixture of graphite and metallic chloride. Composite states of graphite and chloride particles were varied by the preliminary treatment, ie high-energy ball milling for different time or heating at different temperatures. These samples were subjected to the measurement of the rates of weight loss mainly due to the oxidation of carbon, the formation of absorbent organic chlorides (AOX) and the formation of PCDD/Fs at 300¦C. The amount of PCDD/Fs formation increased by applying certain pretreatments. Further, linear relationships were obtained among the formation rates of PCDD/Fs and AOX and the weight loss of sample. These results will give useful information to investigate the mechanism of PCDD/Fs formation from unburned combustible carbon and hydrocarbon in thermal processes.

Jan 1, 2002

The extractive industry has been faced with a situation where there has been no systematic and formalised training and education structure available. Previous structures which were available, e.g. the quarrying diploma and the mining papers as a part of an engineering degree, have suffered the same fate as the Dodo. They are now extinct.   In providing for a training strategy, the past strategies need to be examined and reasons behind their demise examined. This paper examines the reasons for past failures in education and training in the extractives industry, the factors that need to be taken into account in creating an education and training culture, the strategies required, the Government regulations and trans-Tasman agreements, and the quality management which must surround the entire training programme.

Jan 1, 1997