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By A von Johannides, G J. van Hout, L F

In the past various systems have been used to plan the extraction of ore from block cave operations. These systems have varied from rather sophisticated models with empirical ægravity flowÆ rules applied to the very rudimentary models where only the recorded mined tonnageÆs have been accounted for against the available resource. The normal requirement of these models has been to only plan the movement of ground through the drawpoints. Little cognisance has been taken of the other parameters that affect the total mining operations. The intended purpose of the linear program planning system is to not only include the management, resource availability and geotechnical constraints, but to also include the mining rules. The paper will discuss the various constraints that have been considered, and attempt to illustrate where the system better serves the production system than previous ones. A brief technical discussion on the linear programming system is included.

Jan 1, 2000

By Grieveson P, Terry B. S

Carbothermic reduction of sulphide minerals for achieving a selective separation of metallic species from complex minerals has been discussed by considering the prevailing oxygen potential during the course of reaction. Construction of univariant plots for the reduction of sulphides with carbon monoxide gas or carbon and in the presence of either lime or anhydrous calcium sulphate is the key feature of this work. The theoretical calculations for univariants in the Cu-Fe-S-O system indicated a preferential separation of metallic copper and iron by imposing a chemical potential. This is evident from a logarithmic plot of sulphur dioxide partial pressure against reciprocal temperature. The results are compared with empirical data for the reduction equilibrium. The reduction behaviour of the constituent sulphides are also discussed together with the experimental results and theoretically predicted phase stability diagrams.

Jan 1, 1992

By Z U Bajwah

During the Palaeoproterozoic, a large number of granitic intrusions were emplaced in the various parts of the Pine Creek Geosyncline (PCG). In the central region, the granitic magmatism is represented either by the coalesced mass, eg the Cullen Batholith, or individual plutons such as the Mount Bundey Granite which together with the Mount Goyder Syenite intrude the metasedimentary strata, causing wide spread contact aureoles. Some of these granitic intrusions are temporally and genetically related to gold (and less commonly base-metals) mineralisation present in the adjacent metasediments. These plutons are characterised by the presence of biotite and homblende which appear late in the paragenetic sequence. Electron microprobe analyses of biotite and homblende show that these minerals are poorly to moderately zoned. Biotites are characterised by a decrease in Fe/(Fe + Mg) ratios when plotted against AIVI. Similarly a modest decrease in Ti from centre to the margins of the biotite crystals has also been observed. Furthermore, an increase in Mg/(Mg + EFe) ratios from centre to the margins as well as in mafic to felsic rocks is also apparent. On the other hand, homblendes from the granitic bodies display less well marked trends and are poorly zoned. However, they show systematic increases in Mg/(Mg + EFe) ratios, and decreases in Fe, Al"' and Fe/(Fe + Mg) ratios, when plotted against Si. Magnetic susceptibility measurements on powdered samples of the plutons give results characterised by high values ranging from 0.8 x 10-4 to 2.0 x 10-3 emu/g which place the granites in magnetite- series field. This indicates that the oxidation state of the magma was high during crystallisation. The range of chemical compositions of the mafic phases indicates a rise in the oxidation state of the magma as it progressively became saturated in H20-volatiles and other metals, not partitioned into the earlier crystallised phases in the final stages of magma consolidation. These variations in chemical compositions also indicate that initially fOz was high and became progressively higher during fractional crystallisation of magmas; this subsequently led to the emanation of hydrothermal fluids responsible for the mineralisation in the adjacent metasediments.

Jan 1, 1994

By S Walters

The emerging discipline of ‘geometallurgy’ is not new but is becoming increasingly recognised as a discrete and high-value activity. Geometallurgy involves a quantified and spatially constrained approach to ore characterisation in terms of relationships to critical processing performance behaviours. A key outcome is enhanced economic optimisation of mining and improved risk management tools.Industry recognition of the need for large-scale, integrated research to support this emerging area resulted in commencement of a major ongoing initiative in mid-2005. The AMIRA International P843 ‘GeMIII’ project (Geometallurgical Mapping and Mine Modelling) is a cross-discipline collaboration involving a number of world-class research organisations supported by over 20 industry sponsors.The project is delivering integrated tools and methods which link intrinsic rock characteristics to prediction of mineral processing performance. These indices must be capable of spatial distribution in 3D resource models and incorporation into mine planning and optimisation. A key aspect is provision of new cost-effective tools and methods which can provide the large numbers of measured and estimated data points required to undertake effective modelling and spatial distribution. The integrated methodology and enabling technologies being developed through the ongoing AMIRA GeMIII project are outlined, together with implications for supporting industry best practice.

Sep 5, 2011

MR. L. C. BALL, chief government geologist, Queensland, wrote: This paper is intended as a severely mechanical exposition of the means adopted to deal with tremendous inflows of water concurrently with development and exploitation; but incidentally it serves as a splendid exposition of close co-operation maintained between the geological and engineering branches of this large organization.I have been impressed by the completeness of the mine plans of 'Mount Isa Mines Ltd.; but only such a paper as this has brought fully to my understanding the difficulty and complexity of the solid geometry involved in the detection and plotting of the orebodies and their stratigraphic control, including faults and large-scale brecciations, and the managerial foresight that set going the initial investigations.The company's geological branch of course must be given full credit for the results attained, but it gives me pleasure that the Geological Survey of Queensland has been closely associated in much of the study.It is noted that complete drainage was affected, but it would be interesting to learn whether the brecciated zone will again become waterlogged and whether from above or from below, and whether there has been any change in the dissolved mineral content of the water as the work progressed.

Jan 1, 1939

By R Fletcher

Pacific Hydro, a leading renewable energy company from Australia, is developing a series of cascading run-of-river hydro electricity projects in the Cachapoal Valley at the base of the Andes Mountains some 100 km south of Santiago in Chile.These projects involve extensive tunnelling and underground works. The first of these projects is called Chacayes (110 MW installed capacity) and is now under construction with Astaldi SpA of Italy and Fe Grande of Chile as the EPC contractor. Astaldi SpA also has an equity stake in the project. It involves 6 km of tunnels between 5 m and 7 m diameter, of which 2.3 km is by tunnel boring machine (TBM) (5 m diameter).This paper outlines the local and regional geology, the scope of the Chacayes project, actual tunnel excavation rates and support, and compares the decision making on Chacayes between a choice of traditional drill and blast excavation versus TBM.The paper also outlines the next project planned to be developed by Pacifi c Hydro in the valley – the 140+MW Nido de Aguila project involving a main tunnel drive of 11 km with two intermediate adits, plus a 388 m shaft and underground powerhouse. The main tunnel drives are likely to be excavated by two hard rock TBMs (5 m diameter) but will need to be able to withstand high overburden pressures of up to 1300 m.Subsequent projects in the planning stages include the downstream Coya II project with two tunnels totalling approximately 10 km, one of which may be by TBM.

Mar 8, 2011

By Freeman NV

The concept of an in stream analysis probe was developed at The Zinc Corporation (now Z.C. Mines) in the late 1960's and commercialised quite rapidly, by Phillips and then AMDEL, as an alternative to the established centralised systems (Courier, etc.). The developments which have taken place since that time are reviewed and current procedures and performance are described. An audit of the system, recently undertaken by AMDEL, has highlighted areas where improvements can be made. In 1988 the ISA system will become an integral part of a substantially upgraded process control system.

Jan 1, 1988

By Tack K

During its 28-year life the MHD ISP smelter has gone through two phases, each of about a dozen years. The first phase was a learning one; in the second phase the lessons were applied and throughput and production rose strongly. Early experience revealed the robustness and the flexibility of the Imperial Smelting Process. The experience was demonstrated by strong increases in the throughput of mixed lead-zinc concentrates and of secondary (oxide) zinc materials. Purchased material quantities rose from 175 000 tonnes/year to 200 000. The required capacity increase of the IS furnace to smelt the higher throughput was achieved by relatively minor modifications; for instance a change to the internal furnace profile gained an extra two square metres in cross sectional area. The furnace hearth area has remained practically unchanged over its entire history. The paper concludes that there is still more potential to be drawn from the process and MHD intends to sustain raw material input at a new level of 240 000 tonnes/year. However, this rate will have to be achieved under the imposition of more stringent environmental and product quality standards than ever before.

Jan 1, 1993

By H Fukaya T Miki, J Gamutan

Molybdenum disilicide (MoSi2) is a promising material for thermal applications due to its excellent heat and oxidation resistance. It can operate at temperatures of up to 1800°C as furnace heating elements and protect refractory metals such as molybdenum from rapidly reacting with air to form volatile molybdenum oxides at elevated temperature. In this work, the feasibility of forming MoSi2 on a molybdenum substrate by hot dipping in a silicon-saturated molten metal bath was investigated. This method is simple, predictable and can be used to coat large components and complex parts. It was found that tetragonal MoSi2 can be successfully synthesised on the surface of the substrate after dipping for 15 mins at 1000°C using molten tin (Sn), bismuth (Bi) and copper (Cu) baths. The growth of the MoSi2 layer was fast within the first 15 mins and then gradually slowed down with time. After dipping for 60 mins at 1000°C, the thickness of the MoSi2 layer were measured as 441.5, 19.5 and 13.1 μm for the copper, tin, and bismuth baths, respectively. The MoSi2 coating synthesised in this study provided oxidation resistance at 1150°C by forming a protective SiO2 layer on the surface. The SiO2 layer prevented the sample from rapidly oxidising by inhibiting direct contact between the molybdenum substrate and oxygen in the atmosphere. Compared to conventional methods, the proposed hot dipping method produces a MoSi2 layer more rapidly and at much lower operating temperatures. This makes it a more attractive option for coating large and complex components, with the potential to enable the use of MoSi2 in a wider range of applications.

Jun 19, 2024

By R Verreet

In April 2000 Mount Isa Mines installed hoist ropes of a new design on the double-drum winder at their P49 shaft. The ropes, CASAR Duroplast, were about three times as expensive as the previously used triangular strand ropes. The P49 shaft is situated at Mount Isa MinesÆ George Fisher Mine, located some 30 km north of Mt Isa. This shaft used the tried and proven 6 x 33 triangular strand style ropes. The rope life attained by these ropes at the time was acceptable due to many years of satisfactory performance. The following study indicates the improvement of service life using CASAR Duroplast rope in P 49 shaft, which depends on shaft and winder parameters of that particular shaft and cannot necessarily be generalised to other shafts.

Jan 1, 2005

By AJ LYNCH

Broken Hill metallurgists have been responsible for some of the most important developments in mineral processing technology. These occurred mainly in two periods, 1902 - 15 and 1955 - 70. Mineral flotation was developed as an industrial process during the first period and this happened in two stages, the recovery of zinc minerals from the tailings dump accumulated during the gravity concentration of the oxidised ores and the selective recovery of galena and marmatite during flotation of the primary ores. During the second period fast accurate analytical procedures were developed to provide rapid assessment of process performance, and new means of controlling the process were devised which improved throughputs, grades and recoveries. These technological successes were due to the skills of the metallurgists and the commitment of the companies. They brought large financial returns. They were achieved under difficult circumstance. There are important lessons to be learnt from these successes.

Jan 1, 1992

Although mining, particularly of gold and coal, played a significant role in the development of New Zealand, from the time of the spectacular gold rushes of the 1860s its economic importance to the country as a whole has decreased substantially since that time. Gold, coal and non-metallic agricultural and industrial minerals have been found in economically significant quantities, however, the search for base metals has not been successful.

Jan 1, 1982

By J P. Barkas

World demand for iron ore is far from peaking, and the substantial price decline that has captivated commentators since early 2014 is not the result of widespread misreading by producers of the prospects for global market growth. Recent price movements provide little useful insight into the industry’s longer-term fortunes, apart from reminding mining companies that their businesses need to be robust against the volatility and inescapable cyclicality of mineral commodity markets. It is timely to take a strategic view of the history and longer-term prospects for the iron ore industry and of Australia’s place in it.CITATION:Barkas, J P, 2015. Perspectives on the long-term outlook for iron ore, in Proceedings Iron Ore 2015, pp 3–6 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

In classical drill and blast underground mining methods, especially narrow vein operations economic quantities of broken ore can be left behind following normal mucking operations on the stope floors. The ore left behind can have significant economic value and if not collected can be lost forever. This paper reviews techniques for cleaning this material from stopes that have been used in the past and reviews possible modern techniques that can be applied to ensure this valuable material is removed from the stopes.

Aug 1, 2010

By Grady B. V O, Cavell K. J, Ault A. R, Newman O. M G, Malcolm J. McPhersqn

Cyclic voltammetry (CV) has been evaluated as a technique for monitoring the quality of an industrial zinc sulphate electrolyte. The basis of the method involves measuring a change in the polarisation of the zinc nucleation reaction at an aluminium surface and relating this to the impurity content and/or the overall quality of the electrolyte. Specifically, the technique aims to be able to indicate and quantify detrimental synergism between impurity elements, something which traditional analytical techniques are incapable of providing. The technique has found some success with regard to monitoring glue additions in a range of metal electrolytes. It has been found that investigations by a number of workers over the past 15 years have produced variable and often misleading results due to the inadvertent use of commercial purity aluminium working electrodes. It has been shown that impurity elements in the working electrode can give rise to a range of responses that are not obtained when pure aluminium is used and that the response is variable due to the lack of surface homogeneity of commercial purity aluminium electrodes. Furthermore, it was demonstrated that previous detection limits reported in the literature were based on the presence of additional peaks in the cathodic scan and not polarisation effects. The results of this study have shown that when a pure aluminium working electrode was used, the method was incapable of detecting any change in polarisation for an electrolyte containing three common impurities (Co, Ni and Ge), at concentrations that would significantly reduce optimum electrolytic performance. A range of methods was tried to sensitise the technique, including raising the temperature and acidity, and adding antimony in order to induce some synergism. In all cases the polarisation response was unchanged. Consequently, apart from the commercialised application for monitoring additions of antimony and levelling agents such as glue, CV has very limited application as an electrolyte screening technique.

Jan 1, 1993

By Rowe J

The case study is based on the largest ore deposit at Mt. Lyell; the Prince Lyell deposit, comprising a regular lensoid mass of dissemina- ted and vein pyrite-chalcopyrite mineralisation. Reserve estimation employs conventional techniques, based on diamond drill hole and relevant development sampling data. Probable ore reserves are estimated using the contouring (isoline) method an longitudinal projections for ore thickness and accumulation (m %Cu) at a '0.8% Cu' cutoff. Final stope and pillar res- erve estimates (proved ore) are derived from designed ring tonnages and contoured accumula- tion for individual mining units, following more intensive sampling. Systematic grade control procedures have been adopted and individual stopes and pillars reconciled against mill production. The proved ore estimates have been found to com- pare favourably with the reconciled production.

Jan 1, 1979

A review is given of progress made to- wards the development of personal gravimetric dust sampling for risk assessment on South African gold mines. The present strategy is critically examined on the basis of principles for assessing health hazard from dust exposure. Reasons are advanced for replacing the konimeter with a gravimetric system based on full shift personal sampling. Constraints imposed by local characteristics of gold mines are used to illustrate the difficulty in finding suitable instrumentation for measuring personal exposure to respirable silica.

Jan 1, 1988

A new approach to resource estimation at the exploration stage is emerging, based on the application of simple software techniques. The techniques combine the power of interactive graphics with proven database, analysis and estimation tools. With effective use of these tools the geologist now has maximum chance of deriving a reliable structural and grade model from the limited exploration data. Unlike cutoff-based polygonal methods, the resultant geological model can immediately be used to evaluate any economic scenario.These modelling techniques are embodied in MINEX-3D, an Australian software system. With the emergence of the 386-based PC and high resolution (VGA or better) graphics, MINEX-3D makes the power of this new 'desktop geological modelling' accessible to most exploration geologists.

Jan 1, 1990

The screening of iron ores, sinter and coke, and investigations undertaken to improve screening efficiency and cloth life are discussed. The major modifications to coke screening proposed with the construction of No. 7 coke ovens battery are briefly described. The major problem areas were identified as screen cloth blinding and pegging, feed presentation and screen overloading. Blinding and pegging have had a significant effect upon screening efficiency with the screening of sinter, coke breeze and wet iron ores in particular. Pegging can be reduced or eliminated by the correct selection of aperture size and shape, screen excitation and slope, and screening medium. Blinding encountered with wet coke breeze was a particular problem in which no significant progress was made.

Jan 1, 1984

This paper will trace the development of underground coal mining machinery from the days of the tiny air-powered machines to today's 60-ton electric-powered continuous miners. Some important design features which have made the modern fixed-drum continuous miner a success will be examined.

Jan 1, 1978