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Deposits of manganese oxides and silicates in the Tamworth area were re-examined. The major deposit at Danglemah consists chiefly of rhodonite and the rare silicate tephroite. It is considered that the manganese was deposited with the original sediments, the silicates being formed later during the intense folding and low-grade metamorphism of the enclosing rocks.INTRODUCTIONMany small deposits of manganese oxides and silicates occur along a belt of eastern New South Wales and Queensland.Some fifty occurrences, most of which have been subject to mining activity, were described by Lloyd (1943) and some of this information was summarized by Knight (1947). The ores have been mined on a small scale since 1884. Small supplies of battery grade ore were won from a number of deposits, while larger quantities of metallurgical grade were sold to the steel industry. Maximum production was in 1918, when 6,500 tons were mined.The siliceous nature of many of the ores and their occurrence in the neighbourhood of granite batholiths led earlier investigators to consider the deposits to be of hydrothermal origin, associated with the granite intrusions. The present work questions this viewpoint.In this investigation, three of the chief deposits in the Tamworth area were seen. These were at Danglemah, which is being mined at present, and Mount Jasper and Manganese Mountain, which were mined in the past. The Danglemah mine is the most accessible and yields the best material...

Jan 1, 1962

Fundamentally, the development of a minerals processing project is a very risky enterprise. Most mining companies do not have sufficient financial resources to undertake significant projects and hence have to undertake external financing. Indeed, most resource companies understand the high risks associated in developing their projects and therefore, wish others to share in the risks. Most merchant banks, on the other hand, are searching to find suitable resource development projects in which they can share their risk and also share a large proportion of the ærewardÆ. To resolve this issue a Feasibility Study is completed by the project developer and assessed by the merchant bank often with the assistance of an æIndependent EngineerÆ (IE) who assesses the validity of the development proposal. Generally speaking, unless the Feasibility Study has been prepared improperly, the technical aspects of most mineral projects are reasonable. Some of the more recent so-called æhigh techÆ projects are exceptions but these still do not present major technical mistakes or misconceptions. p> In most cases, the major criticism the IE presents after discussing the validity of the ore reserves focuses on production plans, capital costs and operating costs. Of these three parameters the production plan is one in which owners tend to be far too optimistic and financiers, until recent years, have not taken a position. The most critical part of the development plan is the ability of the project, as designed, to attain the required design performance and, even more critically, the ability of the owner to reach and sustain this level of production. In short, how long should the æramp-upÆ be planned to take? Financiers have become more circumspect and are now taking a more conservative view of new project performance by factoring into their project financial analysis longer periods of ramp-up, higher capital costs and higher operating costs. However, these financiers can also be part of the æproblemÆ if they become overly conservative. This paper attempts, by way of case studies available from the public arena, to identify the pitfalls the project owners can meet and possible means of avoiding the disastrous financial conundrum whereby the second or third æownerÆ is the company that reaps the rewards initially extrapolated. The paper briefly discusses this problem by referring to projects known to the author and including previous studies that looked at this very problem. It is emphasised that many of the opinions stated within the paper are strictly those of the author and could be subject of much debate.

Jan 1, 2003

THE reduction of iron from the ferric to the ferrous state prior to its titration by permanganate or dichromate may give erroneous results in the presence of other reducible metals such as titanium. Stannous chloride and metallic zinc both reduce tetravalent titanium to a lower form, and so increase the consumption of the oxidizing standard: solution. Sulphuretted hydrogen and sulphurous acid do not reduce titanium, but are slow in action and troublesome to manipulate.Sulphuretted hydrogen is considered to be the best reducing agent for iron in the presence of titanium.* In the method to be described the advantages of the H 2S reduction are retained without the disadvantages of using the gas. The reduction is carried out by the action of a metallic sulphide having a solubility product of such a value that the sulphide iom, are utilized as fast as they are formed, and but little free sulphuretted hydrogen is given off.Cadmium sulphide was the first to be tried, but its solubility product (3.6 x 10 - 2~)t was apparently too low. The reduction was satisfactory, but the excess was very difficult to remove. Zinc sulphide (S.P. = 1.2 x 10 - 23) was found to be quite satisfactoryin both respects. The zinc sulphide is preferably used in the form of an emulsion prepared from pure zinc sulphate as follows: About 100 grm. of ZnS047H20 is dissolved in 2 litres of water. H2S is passed until no further precipitate is obtained, the acid formed being barely neutralized from time to time by the addition of ammonia. The precipitation of the sulphide in a slightly acid solution gives a finer emulsion than that prepared in an alkaline solution, and any iron present remains dissolved. The precipitate is allowed to settle and the clear liquid decanted. The precipitate is then shaken up with more water, acidified with a little sulphuric acid, allowed to...

Jan 1, 1922

By T Mizuta, D Ishiyama

The Vienna Wood hydrothermal is hosted by mid-oceanic ridge type basalt in graben morphology and is located in the Central Manus Basin. The hydrothermal field is about 300 metres in diameter and consist of a sulphide mounds and tall huge death and active chimneys. From the three distinct ore types collected from the Vienna Wood site, the dominant ore minerals recognised are pyrite, wurtzite, sphalerite, chalcopyrite, Fe-oxide and gangue minerals of anhydrite, gypsum, barite and silica. The consistencies in the paragenetic sequence and in the spatial distribution of the sulfides across the three ore types suggest that similar hydrothermal process exist across active and death chimneys. Fluid inclusion studies reveal a homogenisation temperature of 190-260¦C and an average salinity of 5.1-5.4 wt per cent NaCl equiv. The pH of the hydrothermal fluid ranges from 4.2 to 6.1. Bulk chemical analyses indicate that the mineralisation in the Vienna Wood can be classified into the Zn-(Cu-Pb) type of mineralisation. The tenors of the ore and mineral assemblage resemble those of the Mid-oceanic ridge system and ancient ophiolite hosted massive sulphide deposits of Cyprus and Oman.

Jan 1, 2002

By A Nisbett

The largest single operating loss in many hydrometallurgical plants is the poor recovery of leached product in the solids sent to tailings. Any reduction in the concentration of the valuable species in this stream will improve the project economics. Conventional design, to reduce the soluble loss, is to increase the number of wash stages or the wash/water ratio. This approach is limited in effectiveness as it can only reduce the soluble loss to that dictated by the concentration in the returning solution. For copper plants this concentration is set by the recovery in the solvent extraction (SX) plant. When using a single grade of SX feed a single grade of SX raffinate is produced generally with five to seven per cent of the copper still remaining in solution. An alternative approach has been developed by Cognis Corporation and implemented on a number of recent projects using engineering input from Miller Metallurgical Services. The SX plant feed is æsplitÆ into two different streams: a high-grade stream containing up to 75 per cent of the copper and a low-grade stream with the remaining copper. This Split-CircuitÖ concept has significant benefits in terms of both copper recovery and reduction in acid costs. The high-grade stream has the bulk of the copper removed and the raffinate sent directly back to the leach; to fully re-use the acid that has been generated during extraction in the SX process. The recycling of this higher concentrated acid stream considerably reduces the acid in the raffinate sent to washing steps. It represents a significant saving in acid consumed via the tails stream. The low-grade stream has a significantly lower SX feed grade and hence produces a lower raffinate acid and copper concentration. This lowers the economic species in the wash solution and hence reduces the soluble loss accordingly. Other operating improvements are realised with lower neutralisation costs (with the lower acid in the wash stream) and from a decreased need for in-circuit neutralisation to improve SX performance. The SX plant itself is also split into a high-grade extraction and a low-grade extraction stream to enable the low-grade raffinate to be produced. A number of circuit alternatives have been utilised that have provided a range of benefits. The circuit concept has been included into both new and existing plant operation. As a result of this experience other methods of incorporating the concept into a circuit have been developed.

Jan 1, 2005

By P Licence, M Stevens, P Atkinson, J L. Mauk

The Rahu and Ascot epithermal Au-Ag prospects are two km north of the Karangahake deposit in the Hauraki Goldfield, and all occur in an approximately 6 km2 north-south elongated magnetic æquietÆ zone. The prospects are hosted by andesitic flows, lithic-crystal tuffs and local sedimentary rocks; local silica sinter occurs at Ascot. These host rocks are intensely altered by quartz, adularia, albite, chlorite, pyrite, illite, interstratified illite-smectite and calcite. Several minerals show zoned distributions, such as widespread adularia that overlies more localised and deeper albite. Illite is the only dioctahedral phyllosilicate in several drill holes, but elsewhere it forms a shallow carapace underlain by interstratified illite-smectite with 50 to 90 percent illite. Veins are common with quartz dominating near the surface and calcite becoming more abundant at depth. Local laumontite-calcite veins also occur. Pseudosecondary and secondary fluid inclusions in quartz and calcite at Rahu and Ascot have homogenisation temperatures (Th) that range from 162¦ to 268¦C and 128¦ to 243¦C, respectively. Most inclusions have trapped dilute fluids with salinities of less than 1.9 weight percent NaCl equivalent, but 20 percent of the inclusions have salinities of 2.0 to 10.5 weight percent NaCl equivalent. Calculated paleowater table elevations suggest that the water table at Rahu occurred at 440 m above sea level (asl). At Ascot, silica sinter formed from discharging geothermal fluids (=100¦C) at the paleosurface at ~135 m asl. However the sinter also contains comb quartz with pseudosecondary inclusions that have a Th average of 229¦C, corresponding to a paleowater table at ~430 m asl during inclusion entrapment. Taken together, these results suggest that the Ascot sinter was buried by approximately 300 m of cover material during a major volcanic or tectonic event, and that subsequent hydrothermal fluids formed veins and alteration at Rahu and deposited comb quartz at Ascot.

Jan 1, 2007

The Fiji islands are the world's most ac- cessible Cenozoic remnant arc. They provide occasional subaerial exposures of an arc frag- ment some 750 km long and 80 km wide, or about the size of the NE Japan volcanic arc. The fragment is one part of the former Vitiaz Arc which once connected Fiji to Vanuatu and Tonga. The Fijian portion has the most completely stu- died Tertiary section which contains a history of arc volcanism from the late Eocene to late Miocene (the Early and Mature Arc stages), a rich diversity of subsequent magmatic responses to the most recent episode of arc rifting (Ear- ly Rifting stage), and an example of transition from arc to intraplate volcanism as this rift- ing proceeded (Late Rifting stage). The arc fragment is surrounded by younger backarc ba- sins. The chemical composition of magmas in both the arc and backarc changed with time, but in opposite directions. In the arc, magmas be- came enriched in sialic components from the Early Arc to Early Rifting stages, whereas in the basins the magmas became more similar to mid-ocean ridge basalts (MORBs) with time. In southwest Fiji, the oldest backarc basin has subducted obliquely beneath the remnant arc du- ring the last 3 Ma, resulting in chemically ex- otic calcalkaline volcanism. During the last decade over 150 radiome- tric age measurements and 650 rock analyses, many with trace element and isotopic measure- ments, have been obtained for samples from Fi- ji, Tonga, and the surrounding seafloor (Figs. 1 and 2). These data are summarized, drawing from the publications of Colley and Hindle (1984), Gill et al. (1984), Hawkins and Melchi- or (1985), Kroencke (1984), Malahoff et al. (1984), Scholl et al. (1985) and Whelan et al. (1985), from the specific research papers refe- renced therein, and from the half dozen or so manuscripts currently in preparation by these people and others.

Jan 1, 1987

By M P. Schwarz

This paper describes modelling studies of the flotation cells used by BHP Billiton Nickel West Ltd in the slimes circuit at Mt Keith. The aim is to achieve a better understanding of the hydrodynamic limitations in the existing cells to improve nickel recovery. Computational fluid dynamics (CFD) simulations have been performed on the 100 m3 mechanically-stirred cells. The data produced by the simulations include velocity vectors, gas holdup distribution, solids distribution, bubble size, superficial gas velocity and turbulent parameters. These results have been checked and found to match hydrodynamic measurements at the plant. An analysis of the data found that one of the limitations in fine particle recovery was related to the air bubbles discharged with the tailing. The air in the discharge was caused by the high viscosity of the pulp. In the presence of fine particles, the pulp exhibits high viscosity with a yield stress. The increased drag due to high viscosity caused the bubbles to rise more slowly up the cell. This results in a significant hold-up of bubbles, some of which report to the tailing with associated loss of valuable minerals. A parametric CFD study of the operating variables shows that less air would be discharged in the tailing by decreasing the following: air flow rate,pulp density,stirring speed, andfrother addition. Simulation results indicate that these changes would cause a lowering of the air hold up in the cell especially near the discharge area. Predictions of the bubble-particle attachment rates under various operating conditions have also been calculated. Although it is possible to increase attachment rates by increasing stirring speed or by increasing pulp density, the amount of air discharged and the amount of nickel loss through the tailing will also increase. The project showed that CFD modelling is a powerful tool for studying hydrodynamic effects of bubble-particle interactions in flotation cells.

Jan 1, 2008

By S Coughlan

"A personal account of my journey from a student from suburban Melbourne in the 1970s through 40 odd years in and around the mining industry including the important events that have moulded my thinking and, as result, have formed the guiding principles of the mining contracting business and related entities that make up the Byrnecut Group. On reflection the game of chance has played a big part in the journey, from the selection of initial study based on my parents financial capability and the one and only offer of early employment by Western Mining Corporation where the formative phase of my career took place in what was the vibrant can do environment that existed in Kambalda in the 1970s and early 1980s. Subsequently the unplanned meeting with Frank Lubbock drawing me back to Kalgoorlie from Fiji in 1987 and the resultant formation of a private mining contracting business, the excitement of the mid 1980s Kalgoorlie mining environment followed by the turmoil of the 1987 stock market crash where business survival was the game, resulting in a relationship with the German based Thyssen Group.Thereafter the development of a large privately owned international multifaceted mining services group and the principles behind that growth. These include: development of strategic personnel and retention of those personnel cashflow management and debt within a private company scenario recognising opportunity for synergetic growth but insisting on market forces driving those business elements, as opposed to internal divisions group-wide sustainable business systems, particularly in relation to leading safety and training processes innovation and renewal to provide the elusive advantage in a competitive market the role of entrepreneurial small businesses in development of technology.The above principles combine to make a margin in a cut throat contracting environment, competing on the world stage against other contractors and owner mining options.CITATION:Coughlan, S, 2014. A miner’s journey, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 3–10 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

The Honourable Neil Pickard has been in Parliament for something like sixteen years. He was Minister for Education in 1976, served as Shadow Minister in a number of portfolio areas while his party was in opposition, and since their return to power in 1988, he has been the Minister for Minerals and Energy. Ladies and gentlemen, I ask you to welcome the Minister, the Honourable Neil Pickard.

Jan 1, 1989

By D Thornton

Geologists use large data sets and spend many hours and much computing time modelling the distribution of minerals throughout a rock mass. Significant investments in drilling, assaying and quality assurance and quality control (QA/QC) are made before sophisticated geostatistical techniques are applied to the collected data. A large amount of research has been done in this field such that the ore control model is a reasonably accurate reflection of the mineral that is actually in the ground. However, after all this effort, the mining engineers then work just as diligently to blast the in situ rock mass to a particle size that can be efficiently handled and further reduced by downstream comminution processes. In open cut mines, this invariably requires large amounts of explosive energy that displaces the ore boundaries from where the geologists originally defined them. Failure to accurately account for blast movement will result in misclassification, whether that is ore to waste; low grade to high grade; sulfide to oxide; or other contaminates û collectively referred to as ore loss and dilution. The financial consequence of getting this wrong is substantial and not well quantified. This diminishes all of the good geological QA/QC done in defining the ore. This paper discusses various technologies used to physically measure blast-induced orebody movement and the difficulties in modelling this with a purely theoretical approach. Rock mass structure, blast energy, design and timing contours all have significant and interrelated effects on blast movement vectors. Measured blast movement has a large variance due to the uncertainly of many of the controlling parameters û arguably dominated by the heterogeneous nature of the rock mass. Although there have been significant advances in blast movement modelling capability in recent years, this unpredictable blast movement limits their use in the context of production ore control. Certainly, without physical field measurements, accurate predictions of movement are near impossible.Limitations of traditional surface markers in determining three-dimensional (3D) blast movement within the orebody are also reviewed, and advancements in accurately measuring these vectors within blasted ore discussed

Sep 26, 2011

By J Garritsen, P F. Wells, M Xu

IncoÆs Clarabelle mill currently processes ores from eight mines in the Sudbury basin area in Ontario, Canada. The ore from the Garson mine contains a much higher concentration of arsenic than the other ores. Adding this ore into the feed to the mill has resulted in an increase in arsenic content of the Cu-Ni bulk concentrate to a level that significantly affects the smelter operation, and more importantly the efficiency of Cu-Ni separation in the Matte separation plant. The arsenic occurs mainly as gersdorffite (NiAsS), with a small amount being in the form of cobaltite (CoAsS). Extensive laboratory tests on depressing arsenic in Garson ore flotation have been conducted and two reagent suites have been identified as effective arsenic depressants. One is the so called MAA depressant which is a mixture of magnesium chloride, ammonium chloride, and ammonium hydroxide. This reagent combination was reported to depress other arsenide minerals such as arsenopyrite (FeAsS) and enargite (Cu3AsS4). However, in this study for the first time it has been shown to have a depressing effect on gersdorffite. The other reagent suite, a mixture of triethylenetetramine (TETA) and sodium sulfite, that has been reported as an effective pyrrhotite (Fe1-xS) depressant in pentlandite ((NiFe)9S8) flotation, has not been reported as gersdorffite depressant before. The effectiveness of both reagent suites is more pronounced when the arsenic minerals are oxidised through pulp aeration or the addition of hydrogen peroxide. With a flow sheet consisting of a magnetic separation, rougher- scavenger flotation, followed by regrinding and cleaning of combined magnetic and scavenger concentrate, the arsenic recovery to the final Cu-Ni bulk concentrate was reduced from 73 per cent in baseline test to less than 30 per cent with either reagent suite at no decrease in nickel recovery. The TETA/sulfite reagent combination has the advantage over the MAA suite in that pyrrhotite is also depressed, rather than being activated, and the copper and nickel concentrate grades are therefore increased.

Jan 1, 2005

By Hughson B

The need to prevent the sterilisation of coal stems directly from the fact that it is a non-renewable resource. In N.S.W. a vast amount of coal resource is located under major public utilities such as freeways, railways, stored waters, pipelines carrying gas, water and sewage, and transmission lines. Total extraction has occurred under freeways, transmission lines and pipelines with little or no damage. Where damage has resulted, the cost of restoration was only a small fraction of the value of the coal recovered. However, coal at present is being sterilised and perhaps lost for ever under stored waters and railways. If engineering solutions are available for mining under these improvements economically and with maximum safety, then coal should be extracted and utilised to the benefit of the State.

Jan 1, 1986

By P Mavros, K A. Matis, N K. Lazaridis

A large number of techniques are in use today to limit membrane fouling, among them certainly is air bubbling (which constitutes the transport medium in flotation) as applied in wastewater treatment; meanwhile, dispersed-air flotation is suitable as a pretreatment stage for microfiltration. The invented and investigated hybrid cell combines the advantages of both flotation and membrane separation, while overcoming their limitations, producing clean water from industrial wastewater. Metals recovery from dilute aqueous solutions is a promising application of this innovative hybrid process of flotation and microfiltration, further to solid/liquid separation. In this study, ceramic flat-sheet membrane modules were inserted inside a typical flotation cell in the laboratory tests, using multichannel geometry, combining flotation with microfiltration by submerged membranes; the latter requiring periodic backflushing. The specific objective was to apply this process for the efficient separation of effluents containing metal cations (here, zinc). The main examined parameters were: the initial metal concentration, flotation surfactant applied and air flowrate. The successful contribution of precipitate flotation was highlighted, while the observed metal removals were of the order of ~100 per cent.

Jan 1, 2005

This presentation opens with a definition of technology and how it is implemented. The expenditure and progress on R&D in the mining industry is then investigated and found to be difficult to quantify. The needs and interests of that industry including contribution to this Congress are examined and it is concluded that short-term rather than long-term goals seem to be prevalent. The presentation concludes with the opinion that the answer to the question in the title is both affirmative and negative but overall there is a need for the mining industry to become more innovative.

Jan 1, 1990

When, in 1985, Marty McFly is accidentally sent back to 1955 in a DeLorean ‘time machine’ in Back to the Future, he encounters young versions of his parents, and must make sure they fall in love or he will cease to exist. This Conference celebrates 40 years since the inaugural Mill Operators’ Conference in Mt Isa in 1978; over this period, great technological advances have been made in almost all aspects of mill operation, resulting in considerable improvements in grades and recoveries from ever-more complex ores. However, in 2018, the mining industry is facing challenges that might have been difficult to predict in 1978 (or were they?). The computer revolution, the information revolution, and the bio-technology revolution have all contributed to the increase in operating efficiencies, but, combined with the social revolution, they also call into question the existence of the mining industry as we know it. This presentation looks back at the ‘way things were’ in the 1970s, and at what was then considered to be the ‘basics,’ and attempts to sketch what the mining industry might be like in 2058. As Back to the Future Part II demonstrates so vividly, it is much easier to review the past than predict the future. It is difficult to know what form the mining industry will have in 40 years’ time. Nevertheless, as this presentation will argue, it is important to take action now, to ensure that it (like Marty McFly) does not cease to exist. Some courses of action are proposed, including going back to the basics of a very different past.*This is an abstract only. No full paper was prepared for this abstract.*CITATION:Franzidis, J P, 2018. Back to basics or back to the future?, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 3–4 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

In terms of tunnelling the mining industry is generally thought of as the crude cousin of the civil construction industry. Mining has tended to concentrate on speed and flexibility rather than the high standards required in civil tunnelling. Historically this difference has been based on the belief that such high standards were not required by the mining industry, they would slow down the development of the project and as a result increase the costs and extend the time period between start up and a positive cashflow.For civil works the construction of a tunnel is the project, for mining the construction of declines, crosscuts and drives are merely the means of accessing the orebody so that the real work can begin û MINING. Extraction of ore is the core business of most mining companies û it is what pays the bills.Though most mining companies have the equipment, the people, the knowledge and the ability to excavate tunnels, in the past mining companies did not appear to put the same energy into their tunnelling operations as they put into improving their ore extraction operations. In the past decade this appears to have changed, many mining companies now realise how important the correct excavation of a decline is to the success of the overall mining operation. They began to recognise that there were cost benefits to be gained in using the correct development techniques without overly sacrificing the benefits of speed and flexibility.This recognition also coincided with the growth of underground contractors whose predominant work was primary development (declines and ore access crosscuts and drives). The contractors again had the same knowledge, the same people, and similar equipment but their focus was different from that of the mining company û the contractors were focused on the development of the mine, the excavation of declines, crosscuts and drives. These deliverables were the contractorsÆ core business û itÆs what paid the bills.

Jan 1, 1999

A synthetic gold-silver telluride material (mainly sylvanite) has been prepared and its physical and chemical properties checked. Flotation tests using a Hallimond tube were conducted using commercial xanthate collectors. At collector concentrations of 10-3M with the addition of 5 × 10-4 M CUS04, no obvious differences in the mineral recoveries were seen irrespective of whether amyl, secbutyl, isobutyl or isopropyl xanthates were used. However, when the concentration of xanthate was reduced to 10-4 M or in the absence of the copper sulphate activator, the effectiveness of the collectors was in the order: amyl > secbutyl > isobutyl > isopropyl > ethyl. Changes in the slurry pH appeared to have little effect on the recovery of the telluride mineral.Leaching tests of the precious metal telluride showed that both gold and silver dissolve in alkaline oxygenated cyanide solutions but at a much lower dissolution rate than metallic gold or silver. Both leaching tests and electrochemical measurements indicate that the dissolution rate of gold-silver telluride is controlled by the pH and cyanide concentration of the leachant.Roasting the gold-silver telluride materials in air at temperatures between 550 and 750°C resulted in its decomposition into a metallic gold-silver alloy and tellurium dioxide.

Jan 1, 1994

By Poplawski R. F

A 32-channel PSS seismic monitoring system was commissioned at Mt Charlotte mine in 1994, and at the time it was the first such system in Australian mines. The system continuously observes the occurrence of seismic events and locates them accurately in space and time. Mt Charlotte has a history of seismicity, with the largest event in recent years of Richter magnitude 4.3. The decision to 'go seismic' was made despite some uncertainty regarding its potential usefulness. However after the first year of operation, benefits have been realised in terms of less production downtime, improved mine safety and mine planning, and better understanding of the nature of Mt Charlotte seismicity. The seismic network has performed well, recording 550 events in its first year of operation to a location accuracy averaging ¦ 12 metres. System reliability is excellent, with very little downtime, and acceptable operation and maintenance times and costs. Observations show major distinct changes in the rate of mining induced seismicity over time periods of weeks and months. Events have tended to cluster in specific mine areas and on particular faults and structures. Case examples of pillar preconditioning, breakout around an orepass, and a major stope rockburst, illustrate the role of seismic data and the benefits it brings to safety, productivity and planning.

Jan 1, 1995

This paper describes a steam outburst in a metal mine which occurred in December 1992 in Japan, resulting in two fatalities. The outburst occurred just after blasting in a heading face 600 m below surface (SL-50 m), 1664 m from a mouth of the mine. The scale of the outburst was large and the fragments of the outburst spread up to 34 m from the face, the total volume of the outburst was estimated to be 206 m3. The outburst materials were mostly clay originated from the typical surrounding rock of sulfide ore and basalt. The shape of the larger outburst fragments were slabs with a thickness of 10 to 20 cm. The victims were found in a main ventilation air shaft, 175 m and 380 m from the face, respectively. The mine mainly produces copper, lead and zinc. The face was ventilated by a 560 mm diameter duct with a fan and the strata temperature of the rock was estimated to be in the range of 120 to 140¦C. There is a famous hot spring near the mine. A thorough investigation into the unprecedented accident was made including an on-site inspection and investigation of rock characteristics in laboratories.

Jan 1, 2005