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This paper discusses why Argyle Diamonds adopted thickened tailings disposal in 1985 and how the system was developed over the next seven years. A wide ranging review of the thickened tailings disposal system and the tailings deposit it was producing was carried out during 1992 and 1993. The results of that review led to the abandonment of thickened tailings disposal at Argyle because of serious concerns about the stability of the resultant tailings deposit. The exposure to the risk of liquefaction and an assessment of the consequences if this happened to the thickened tailings deposit are shown. The criteria for selecting the new tailings disposal strategy are then described. The final section of the paper discusses the management strategies that have been put in place. These are designed to: ò reduce the risk posed by the thickened tailings deposit to an acceptable level; ò safely store tailings to the end of mine life; ò produce a land form that can be decommissioned to the satisfaction of Government regulatory bodies.

Jan 1, 1996

By Segnit ER, Boow J

The start up operations of Western Mining Corporation's Kalgoorlie nickel smelter encountered troubles due to the high magnesia content of the concentrates. The flash smelter slags, with higher than normal magnesia content, had a much higher melting point than the normal low-magnesia, predominantly fayalite slags usually produced in nickel smelting. Investigations were made of the structures, melting points and viscosities of the Kalgoorlie smelter slags, as produced, and with additions of silica or lime.

Jan 1, 1980

Proceeding from statistical data on the development of waste volume, an endeavour was made to characterise waste materials with regard to the applicability of treatments based on mineral processing. Many types of waste are characterised by a high heterogeneity. The separation processes used for processing raw minerals can also be used for separation of various waste mixtures. For some waste mixtures, differences in properties can be utilised for separation which are mostly less distinctive for raw minerals. State-of-the-art technology is illustrated with selected Examples.

Jan 1, 1993

By Ault A. R

The recent modernisation program at the Risdon electrolytic zinc smelter of Pasminco Metals - EZ (PMEZ) inyolved significant changes to the composition of cell electrolytes. The most significant were increased acidity and sulphate level, a reduction in Co level, and the replacement of 2-naphthol in the additive mixture with licorice. In determining acceptable operating ranges, a relatively large number of industrial deposition tests under controlled conditions was required. The cathode zinc deposits so produced were examined in terms of overall appearance, crystal structure according to X-ray diffraction, and a micro-roughness parameter. Beginning with typical deposits produced in the presence of an excess of one of the addition agents glue or antimony or a mist suppressant (licorice or 2-naphthol), a simple classification system was developed. In this system, the deposits are divided into the following types: Doughy, Pinholed, Compact and Stressed. There was a weak correlation between deposit type and crystal orientation. In terms of ease of stripping, observations in plant operations showed that only Compact and Pinholed were consistently acceptable. Current efficiency was normally maximised by producing a Compact deposit. Process variables such as zinc concentration, temperature and the use of strontium carbonate were found to cause changes in deposit type if the reagent mixture used was unchanged. From the knowledge gained, guidelines were developed to allow glue and antimony additions to be altered to fit new circumstances. The simple classification system was first used to expedite recovery from undesirable morphologies and then to optimise individual cell units operated under substantially different conditions. It is believed that finer control could be exercised by determining the micro-roughness of Compact deposits. However, difficulties can arise if sudden, large deviations occur and go undetected. Suggestions are given for an improved additive control system. The classification system developed has been compared with published information in the literature, and good correspondence was noted suggesting a predictable relationship between short-term, laboratory deposition tests and observable phenomena in industrial electrowinning cells run under steady conditions.

Jan 1, 1993

This opportunity to present a few thoughts on the question of professional education and training comes at a most appropriate time. In Britain, a great deal of energy is being expended in this, so-called, post-Finniston era, to create a new look for the status of engineers and engineering by the Engineering Council. Naturally, the tune and the tempo are being called by the big institutions which essentially serve the manufacturing industries. However, the Engineering Council in Great Britain also includes the mining and processing institutions such as the Institution of Mining and Metallurgy (IMM) and so there is a chance - if it is taken - for us to contribute to the debate and the determinations that emanate from it. The IMM, of course, caters for the professional status of those engaged in the mining and minerals industries and includes many who do not see themselves as engineers. Nevertheless, the debate is important to these other groups whose livelihood is inextricably bound up with those who are engineers and there are many facets of the engineering policies being shaped that will, I am sure, eventually be enshrined in the requirements for professional status across all the various disciplines in our industry.

Jan 1, 1986

By Askew JE

The large, massive low grade gold orebody at Mount Charlotte has demanded an innovative approach to mining engineering. In the last five years several advances occurred in the areas of rock mechanics, mass blasting, blasthole drilling and truck haulage.Successive crown pillar failures throughout the life of the mine had resulted in a continuous geotechnical program, mostly utilisingconsultants. The culmination of this workwas the development of a successful crown pillar support system. Several stopes have incorporated the technique and the most notable success has been the relatively large F3 crown pillar.In hole hammer drilling was introduced to the mine in 1979, but little work had been done to develop a blasting system to suit the 165mm diameter holes. A non-electric sequential blasting system was adapted for use at themine and up to 600,000 tonnes have been fired successfully in an individual blast. Problems with ground vibration were addressed although this work remains incomplete.

Jan 1, 1984

By Gardner H. J, Wadsley m. W

Bauxite from the Weipa and Andoom (North Queensland) deposits was treated to provide a low-iron raw material for high- alumina refractories or aluminium chloride manufacture. The operation involved passing crushed, calcined bauxite continuously through a single laboratory shaft furnace. Consecutive sulfidation and chlorination of the iron minerals within the furnace resulted in a beneficiate containing less than 2% (wt.) Fe203 and by-product ferric chloride con- taining only traces of aluminium.

Jan 1, 1979

Optimisation of capital in the development process is critical to the profitability of any new mining venture. The process of optimisation should apply to all aspects, that is the financing, management, revenue, reporting and, of course, the development of the project. Unfortunately, too much emphasis has been placed on the optimisation of the financing or reporting aspects and too little on the project itself. This paper addresses the latter.

Jan 1, 1991

Utah's Blackwater mine began operations in 1967. The four CQCA mines controlled by Utah followed over the period 1971 to 1979. Project feasibility studies for all these were based on open cut mining to overburden depths of 60 metres, with typical project lives of 12 to 16 years, depending on reserves Further studies, initiated after the mines had started, showed that continuation of open cut mining beyond the 60 metre highwall was viable. In 1973, the Deep Stripping Project (DSP) was launched to define the scope for stripping deeper, to determine what the additional equipment needs might be, and to pu forward proposals for a full scale trial system. The project commenced at grass roots with a literature survey, proceeded through a sequence of equipment evaluation, specification, design and manufacture to the commissioning of the Goonyella BWE system. Studies are continuing to assess the future deep stripping requirements for all Utah's Bowen Basin mines.

Jan 1, 1983

By H Catchpole, L FontbotT, J PTrez, M Ageneau, A Bendez·

In the world-class mining district of Morococha, epithermal polymetallic replacement bodies and veins overprint porphyry mineralisation and skarns related to subvolcanic intrusions of Miocene age, thus indicating ore formation in two different environments, separated in time or forming a continuum. The district covers an area of about 70 km2 in the north-western part of the Domo de Yauli complex in theWestern Cordillera of central Peru and is part of the Miocene polymetallic belt, also hosting the deposits of Colquijirca (Bendez· et al, 2008b) and Cerro de Pasco (Baumgartner, FontbotT and Vennemann, 2008). Multiple late-Miocene porphyry stocks intruded Permian, Triassic-Jurassic and late-Cretaceous sedimentary carbonate and volcano-sedimentary formations, as well as large mid-Miocene barren intrusions. Extensive field work and detailedmapping of different styles of orebodies suggest that ore formation in the area was related to the late-Miocene magmatism. Good outcrop conditions and superimposing of different mineralisation styles make Morococha an ideal location for studying ore-forming processes in a complex porphyry-related magmatic-hydrothermal system in which porphyry-to-epithermal transition occurred. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Phillips J. T, Hutton W. A

This paper discusses why Argyle Diamonds adopted thickened tailings disposal in 1985 and how the system was developed over the next seven years. A wide ranging review of the thickened tailings disposal system and the tailings deposit it was producing was carried out during 1992 and 1993. The results of that review led to the abandonment of thickened tailings disposal at Argyle because of serious concerns about the stability of the resultant tailings deposit. The exposure to the risk of liquefaction and an assessment of the consequences if this happened to the thickened tailings deposit are shown. The criteria for selecting the new tailings disposal strategy are then described. The final section of the paper discusses the management strategies that have been put in place. These are designed to: ò reduce the risk posed by the thickened tailings deposit to an acceptable level; ò safely store tailings to the end of mine life; ò produce a land form that can be decommissioned to the satisfaction of Government regulatory bodies.

Jan 1, 1996

Five Hypotheses are given for factors influencing long-run metals price forecasts. 1 . Geologists succeed when given the money. 2. Better understanding of a metals market depresses its price. 3 . Statistical techniques get forecasts wrong. 4. Long-run metals prices are related to crustal abundance. 5 . Economic cycles affect metals prices more than is realised. These are then framed within the transition between eras as influenced by apparent long waves in economic activity. Innovation surges during the transition between eras. The transition to the 5th Wave since the Indus- trial Revolution 200 years ago is now underway. Finally, price projec- tions are given both for the 5th Wave and 200 years from now on the assumption that a similar monetary measure to today will be then extant.

Jan 1, 1988

Difficult ground conditions in the area planned for placement of vent rises to the surface at the Porgera Goldmine led engineers directing the project to chose blind shaft boring methods of shaft construction from the available alternatives. Zeni Drilling Pty Ltd was first contracted in 1988 to install a group of three closely-spaced, steel lined shafts. The success of these led to an order for a fourth hole in the same group followed by two more, less than a kilometre. away, under a separate contract in 1992. All of the shafts were completed on.schedule to within one day. The only significant difficulty arose during commencement of the last shaft when the strata collapsed trapping the drilling tools and jeopardising the stability of the surface collar pad. The situation was corrected by innovative lining techniques and the project went on to finish on schedule. This paper discusses the application of various technologies associated with the project including aspects of geotechnical input, drilling fluid chemistry, mining engineering and logistics.

Jan 1, 1993

A simulation model of the load and haul process where the loader cycle has been subdivided into its individual components is used to consider the benefits derived from improved drill and blast methods. Field data from a Hunter Valley mine is u

Jan 1, 1998

Ore reserve estimates form a basis for strategic mine planning at Argyle Diamonds open pit and alluvial operations. Most ore reserve statements are mainly concerned with resource tonnage and grade. Because diamond deposits are low grade, high value resources, diamond quality ($/carat) is also an important parameter. Relatively large variations in quality and/or grade can occur. These variations must be taken into account before the resource potential can be fully assessed. Computers (HP9000 and PC's) are utilised to compile resource inventories. Resource inventories are then ranked on an economic basis. This paper discusses the methods used to compile resource inventories and explains how these are then used to present ore reserve estimates in terms of resource potential.

Jan 1, 1990

By Cox N

Fragmentation control is perhaps the most critical aspect of quarrying operations, potentially impacting on the costs of all down stream processes, and sometimes even on the economic viability of an operation. The focal points of studies to control fragmentation are generally the pattern of blastholes, the accuracy of drilling, and the most appropriate powder factor. Recent studies suggest that the performance, and consistency of performance, of explosive detonation in the blastholes may also be a significant factor impacting on blast performance in hard rock quarries. This paper presents the results of studies of bulk emulsion and watergel explosive performance, using blasthole velocity of detonation measurements, and its impact on fragmentation. Field studies show a strong correlation between blasthole VoD and blast fragmentation. Another aspect of explosive performance impacting on ease of excavation of blasted rock is muckpile displacement, from which estimates of effective heave energy have been made for different bulk slurry (emulsion and watergel) products.

Jan 1, 1995

By Komosa T, Muir D. M

Mixtures of ammonia and cyanide at low concentrations leach gold selectively from copper-gold ores. The effects of various reagent compositions on three different ore types containing between 0.3 - 1.5 per cent Cu are reported. It is shown that the results and optimum compositions vary according to the ore, which is attributed in part to the mineralogy and adsorption of solution species on the mineral surfaces. The solution chemistry of the Cu-NH3-CN system indicates that Cu(CN)a - and Cu(CN)3 species are involved in the leaching mechanism. Rotating disc studies on pure gold and copper are reported which show that the Cu(CN)32- species leach gold at about half the rate of CN but leach copper at the same rate. The presence of ammonia retards the leaching rate further. Mixtures of Cu(CN)a3- and NH3 effectively leach gold from Telfer tailing without leaching copper. The role of ammonia appears to be to control the precipitation of copper rather than the kinetics of leaching.

Jan 1, 1991

By Wharton P, Voigt R

In order to do the discharge estimation better, it is valuable to find out appropriate formulas for estimating discharge in various pits, based on accumulating data, summarizing discharge patterns applying optimum seeking method and principle, by seeking redical exponent with help of the method of exhaustion, as well as testing and making statistics, in accordance with the quality standards established by our practical experience.

Jan 1, 1988

The methods used by the Anglo American Corporation for analysis of long-term metal markets and prices are described. The principal factors affecting the relationships between production costs and metal prices are analysed. These are firstly the type of market, - speculative or consumer commodity, free market or subject to price control; and secondly the rate of growth of demand for the metal. It is shown that virtually all metals will have relatively low rates of demand growth for the foreseeable future, due to market saturation, increased economisation, substitution and product obsolescence. Metal prices have a clear dependance on production costs, however forecasting future costs is by no means simple; amongst other things, account must be taken of changing exchange rates, inflation rates, and the potential for operating more efficiently. The paper concludes by giving brief assessments of the long-term future for aluminium, copper, zinc, nickel and tin.

Jan 1, 1986

The underground coal mining industry in Australia has, in the last 30 years, undergone a revolution in production methods, techniques and results probably unparalleled elsewhere in the world. It can lay claim not only to leading the fight against pneumoconiosis and setting high safety standards generally, but has at the same time recorded comparatively high rates of increase in output per man shift. The latter has been achieved as a result of progressively matching the latest in production and underground transportation equipment with significant changes in seam development and extraction techniques and the introduction of stress-relieving extraction methods unique to the world scene. However, the seam recovery factor is still too low. Apart from the overall objectives of maximising production and commercial returns with the greatest safety, there must be a concentration towards maximising seam recovery, particularly in high seams. The search will continue for systems which are more completely continuous mining operations than the present stop-go operations, with longwall having long term potential in this regard, but as yet not sufficiently developed to engender confidence for its more general use. Techniques developed in the last 10 years make the development and extraction of deeper seams, perhaps to 2500 feet or more, feasible with continuous miners as well as longwall. The future will see a greater use of continuous shifts at mines, larger mines with more sophisticated management organisation, extensible belts at the face, better systems of immediate roof support at the face, remote operation of face equipment, greater use of roof bolts and the longer roof cables. With commercial confidence in coal mining now virtually assured to at least the turn of the century, the stage is set for heavy capital development in the industry which will undoubtedly include major research into the whole area of mining methods and equipment. We must ensure that our contribution to such research equitably matches other coal producing countries.

Jan 1, 1975