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Diamonds occur in N.S.W., Victoria and north west Tasmania. Diamonds from different areas appear to have their own characteristics, lending weight to the suggestion that three or four different sources (different in location and age) have produced the diamonds found in alluvials at quite a number of locations in Eastern Australia. Explorers for kimberlites in Victoria must overcome a number of field difficulties. The writer's approach attempted to find exploration targets by literature search, noting unusual garnet occurrences, and by relating records of diamond occurrences to described mining activity. While the records are biased towards gold, the study did lead to a pipe, located well away from known diamond-bearing alluvials. Core from one test hole has shown this intrusive to include an alkaline ultramafic breccia with many kimberlitic affinities - a breccia containing mantle-derived minerals, but not a true kimberlite. (A detailed rock description is appended to this paper, but is not the purpose of the paper.) This result enhances the possibility that kimberlites may occur in Victoria, on or near large scale faults or grabens. The depth of fracture penetration may have been different

Jan 1, 1979

By Weber W

Methods of calculation of the reliability of process computers are getting more and more important. The paper presents long period observations of 21 process computers with online applications in the iron and steel industry. About 5000 failure events during 10 years have been systematically recorded and evaluated. On the basis of these long time observations it is possible to develop a probability model of the failure behaviour of process computers.This failure model is constructed with four different states of the process computer:Working phase, working phase with undetected reasons, repair phase, failure phase resulting from external influences.The model is defined by differential equations for the probability of one of these four phases. Long time observations show, that all of these four phases are closely correlated with the capa-city of a process computer, restarting without detection of failure reason, changes of programs and software, costs and time of repair. So the result of this analysis is a model of failure for process computers, which allows to predict breakdowns of process computers on the basis of external parameters.

Jan 1, 1985

From time to time failures occur in structures made of lead, and the failure may be due to corrosion involving a definite thinning of the lead sheet, or it may be of such a nature that cracks develop and the lead appears to disintegrate. The idea of lead cracking will at once suggest something abnormal, for common experience shows that this metal is very ductile and will withstand considerable bending without showing any sign of fracture. Cracking, on the other hand, is usually associated with brittleness.Fig. 1 is a natural-size photograph of a cracked sheet of lead. Prior to photographing, the sheet was etched byimmersion in a solution of ammonium molybdate. Several characteristics of this crack will be evident. First of all it is distinctly a zigzag crack, and secondly it passes between, rather than through, certain well-defined areas which appear bright in the photograph. This is particularly noticeable at the lower end where the crack appears to terminate.

Jan 1, 1932

Gold has been known and mined in Australia for over 150 years. It occurs and is mined in all States and the Northern Territory. In the past 30 years approximately 8300 t of gold has been mined and gold exports have contributed over $106 billion to the Australian economy. In the first three quarters of the Australian financial year 2006 - 07 (ending 30 June 2007) gold exports were valued at $7.3 billion, which was 13 per cent of the value of all minerals exported and five per cent of AustraliaÆs total goods and services exports over the period. Clearly gold has been and remains a very important component of the Australian economy.

Jan 1, 2007

The development of present methods of pillar extraction has evolved from the very earliest of hand mining operations which were limited in scope by venti- lation and transport considerations. Conservation and safety considerations also have led to the current shortwall operations with conventional equipment and powered supports. The shortwall methods have had significant effects on safety, costs, con- servation, flexibility, and other aspects of pillar extraction. The present stage falls short of the ideal but is some guide to prediction in what direction may lie the ideal methods for the future.

Jan 1, 1974

The preamble to the mining Act sets out that such Act is to provide for the encouragement and regulation of mining within the State of Queensland. This paper will attempt to follow the legislative path of such aim and in particular to show what part Mining Wardens play in the administration of the Mining Act.The Mining Act empowers the Governor in Council to constitute Mining Districts and Mining Fields and to appoint any duly qualified officer of the Public Service of Queensland to be a Warden or a Mining Registrar. As a matter of practice Stipendiary Magistrates who hold office in the major centre within a Mining District are appointed Wardens and Clerks of the Court are appointed Mining Registrars. In some districts where there is no Stipendiary Magistrate the Clerk of the Court is appointed an Acting Warden with all the powers of a Warden. Every Warden so appointed is a Warden for the whole State.To achieve impartiality Section 74 of the Mining Act provides that a Warden shall not hold or be entitled (directly or indirectly) to the benefits of any share or interest in a mining tenement or mining venture and provides a penalty of $1000 or imprisonment for six months or both, for contravention of such section.

Jan 1, 1986

I WISH to express to the members of the Institute my sincere appreciation of the distinction which they have conferred upon me by again making me their president. It also gives me great pleasure to once more welcome the Institute to Mount Lyell.Since your last visit certain improvements in plant have been made, which I trust you will have found interesting, and which show that, though located in a remote corner of the world, we are abreast of the times.The opportunities which a recent lengthy trip to America has given me to observe the degree of interest which our local smelting practice continues to arouse in metallurgical circles make it seem appropriate that I should take advantage of your visit to lay before you some detailed information on the more practical features of pyrite smelting, particularly as carried out at Mount Lyell. There are only a few places in the world where the method is now being practised in approximate purity-only about half...

Jan 1, 1915

In the flotation of fine particles, problems arise which do not occur with coarse-ground pulps. For example, the presence of colloidal or near-colloid- al gangue particles gives rise to ex- cessive entrainment in the froth, with reduced grade as a consequence. If the values themselves are finely dissemi- nated, the recovery usually decreases as the particles diminish in size, so a low recovery is combined with poor grade. Sutherland and Wark (1955) referred to the complications arising from the presence of fines, indicating (p.382) that fine grinding "introduces diffi- culties that have not yet been satis- factorily overcome". At the time of writing, very little work has been done on fines flotation specifically, yet the groundwork has been well laid. The availability of better scientific instruments, together with the general advance of understanding in a wide variety of relevant research fields, has taken us a long way toward finding the reasons behind the problems as- sociated with fines, and also toward finding practical solutions. It would be useful to define what is meant by "fine" particles before going further. To some extent, the definition is somewhat elastic as far as flotation is concerned, because the density of the particles has a bearing on whether or not they act as fines. But in general we are dealing with particles less than about 20 pm in Diameter.

Jan 1, 1984

By A T. Spathis, M L. Lawlor-O’Neill

A methodology for the inversion of a scaled charge weight superposition model to predict peak particle velocity (PPV) has been examined. The inversion involves two steps: first simulated annealing is used to get an initial estimate of the model parameters; and second, these parameters are used as input to a quasi-Newton non-linear optimisation method, used to refine the value of the parameters. The methodology recovers the three required parameters (two charge weight scaling parameters and a time window width) and does this directly from a single production blast for a given point of interest. It has been tested on a synthetic example and recovered the input model parameters successfully in the presence of introduced noise with a coefficient of variation ranging up to ten per cent. Another test used the vibration measurements of three tunnel blasts monitored during the construction of the Citybanan tunnel in Stockholm. In this case, the three model parameters are found from one blast and for a given point of interest, and the PPV at the same point of interest is predicted for the second and third blast fired in the same vicinity as the first blast. The three blasts used different firing sequences. The predicted PPV limits use a confidence interval determined from the scatter in the peak levels obtained from the single calibration blast. The methodology was able to predict an upper bound for the PPV in 21 of the 26 tunnel blast vibrations studied. These predictions improve on a previous study involving the same model but which did not use the inversion process above. Given this reasonable success, further testing of the method on other data sets and alternative forward prediction models is recommended.CITATION:Lawlor-O’Neill, M L and Spathis, A T, 2015. An inversion method for the prediction of peak particle velocity in blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 97–108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Hunter W. H, Wilson I. P, Craig R. W

In September 1988 the Imperial Smelting zinc - lead blast furnace at Avonmouth England, was uprated from its then 52 week annual rated capacity of 90 000 tonnes/year of furnace zinc to 110 000 tonnes. In order to provide sufficient extra feed the sinter plant was likewise uprated in April 1989 by increasing the blowing rate of the sinter/acid plants from 100 000 to 120 000 Nm3/h, effectively a 20 per cent increase. In the 12 months after the uprate zinc production was only 85 000 tonnes. Two years after the uprate zinc production had increased to 100 000 tonnes, but it was not until January 1992 that a rolling 12-month zinc production of 110 000 tonnes was consistently achieved. This paper describes the problems encountered with the uprate and how they have been or are being overcome. It deals chronologically with events starting with the restart of the ISF at the end of 1988 and covers the following issues and their resolution: 1. Initial shortages of sinter due to an offset in uprate timing. 2. Greater difficulties in operating the larger furnace particularly on start-up, the greater tendency for iron production and serious slagging problems. 3. Coincidental timing of deleterious trends in slag chemistry. 4. Refractory problems in the furnace shaft and condenser. 5. Shortages of sinter due to commissioning problems with the wet gas and sinter tip end fans, and difficulties in obtaining sufficient sinter hardness. 6. Unrealised full benefits of the sinter-acid uprate due to a late change in design to dispense with sinter gas recirculation, but offset by successful use of oxygen. In a planned maintenance stop in September 1992 further improvements to the furnace design were carried out to resolve the refractory problems, and with improvements to the sinter plant the furnace zinc output capacity is planned to rise to a rate of 120 000 tonnes/year within two years.

Jan 1, 1993

Structural analyses of oriented bore core sections from the West Wallsend No.2 Colliery Holding together with investigations in adjac- ent collieries and on the surface delineated structural phenomena. The rocks examined are anisotropic due to strongly developed bedding planes and the presence of penetrative joint planes. Joints, in this context, are regarded as mechanical discontinuities, they are genetically identif- ied wherever possible and their spatial attit- udes are determined and geometrically related to the regional structure. Identifiable anisotropies in the roof- and floor-strata of the Borehole Seam render favour- able mining directions for longwall and bord and pillar layouts.

Jan 1, 1972

By A Moreira, A B. De Souza, S Latchireddi, E Faria

Material transport plays a significant role in the efficiency of horizontal grinding mills - autogenous (AG)/semi-autogenous (SAG)/ball mills. The magnitude of benefits that can be achieved with efficient material transport in AG/SAG mills has been demonstrated in a greenfield milling operation at Mirabela MineratpoÆs SantaRita Nickel operation located in north eastern Bahia in Brazil. This grinding circuit was commissioned in October 2009, was designed as a typical SABC circuit to grind 4.6 Mt/a (575 t/h) to produce a P80 of 125 ¦m with ten to 12 per cent ball charge in the SAG mill. However, it has been operating as an ABC circuit without any grinding media in SAG mill. The nameplate design capacity was achieved in few days and was gradually increased to an average of +800 t/h, still operating in ABC mode. The Santa Rita grinding circuit consists of one 30 ft + 15.4 ft 8.5 MW SAG mill fitted with Outotec patented Turbo Pulp Lifters (TPLÖ) in closed circuit with a HP400 short head pebble crusher and one 20 ft + 28.4 ft 5.5 MW Ball Mill in closed circuit with a Warman cyclone cluster fitted with 10 + 26 in CAVEX cyclones. This paper examines the comminution design process, operating philosophies, experiences, post commissioning optimisation and future development works. Evaluation of the milling circuit performance relative to the design criteria is also discussed.CITATION:De Souza, A B, Latchireddi, S, Moreira, A and Faria, E, 2012. Application of turbo pulp lifter in greenfield operation - Mirabela SantaRita nickel operation, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 53-58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

The last decade has seen a very rapid development in TBM tunnelling. Some trends are purely technical or economical and others relate more to preferences of different interests. Power levels have more than doubled and thrust levels too. Shield machines are developed to be able to handle harder rock and the open TBMs are made more feasible for `difficult' rock. What is right and what is wrong is more a matter of opinion, but one thing is certain: TBMs now are a useful tool and no longer an experimental work-shop for the enthusiasts.This paper highlights some recent developments and indicates some probable future ones. A few features that have increased the open TBMs' ability to cope with ever harder rock and also to overcome problems with poor rock are discussed in detail, using the Atlas Copco JARVA Mk 27 -the most powerful TBM built so far - as a reference.

Jan 1, 1993

By A E. Annels, G F. Johansen, B W. Cuffley

Nuggety gold-quartz reefs are characterised by localised, high-grades and in many cases coarse free-gold. Geometrical and grade complexities are often observed. The high-grade regions are generally erratic and have a low continuity; though may make the deposit economic. Viable grades are generally contained within discrete oreshoots, which are surrounded by barren/low-grade material. Drilling is an effective measure of geological continuity, however grade distribution can only be reliably obtained from underground development and bulk sampling. In general terms, only an inferred resource is likely to be estimated from surface drill data alone. Underground development, further drilling and probably bulk sampling will be required to delineate inferred and indicated resources. Closely spaced development with bulk sampling is likely to be the best way to determine a probable reserve. The resource evaluation process must driven by a clear geological model that should attempt to understand the controls to reef geometry and grade distribution. Geological interpretation has traditionally been undertaken in two-dimensions, though computer software is now being used to produce three-dimensional models. Grade interpolation has generally been undertaken using classical methods, typically weighted averages, zone of influence weighting and polygonal/sectional blocks. Tonnages can generally be calculated from diamond drill and development information with a reasonable degree of confidence. Grade is much more difficult to define with confidence because of its highly erratic and discontinuous nature. To account for variability it is recommended that a best estimate be reported within a grade range, as this more accurately reflects the uncertainties involved. Reporting should be undertaken within the framework of the JORC code, but should involve special consideration of grade reliability.

Jan 1, 2000

By S G. Hagemann, M E. Barley

The Mt Tom Price deposit is a world-class high-grade hematite deposit in the Hamersley Province of Western Australia with an original resource of 900 Mt of almost pure hematite, averaging 63.9 wt per cent Fe. Petrological and geochemical studies at both the Southern Ridge and the North deposit at Mt Tom Price have identified three hypogene alteration zones between unmineralised BIF and high-grade iron ore: distal magnetite-siderite-stilpnomelane; intermediate hematite-magnetite-ankerite-talc-chlorite; and proximal martite-microplaty hematite-magnetite-apatite alteration zones.Fluid inclusions trapped in siderite within the distal magnetite-siderite- stilpnomelane alteration zone at the North deposit revealed primary high salinity (25.5 eq wt per cent NaCl-CaCl2) inclusions that homogenised between 107¦ and 142¦C into liquid. Fluid inclusions trapped in ankerite within ankerite-microplaty hematite veins in the intermediate hematite-ankerite-magnetite-talc-chlorite alteration zone at the North deposit revealed mostly H2O-CaCl2 pseudosecondary and secondary inclusions with salinities of 22.4 - 25.4 eq wt per cent and 22.9 - 25.9 eq wt per cent CaCl2, respectively. Pseudosecondary inclusions homogenised between 153¦ and 449¦C and secondary inclusions homogenised between 103¦ and 157¦C. Fluid inclusions trapped in apatite within talc-microplaty hematite veins in the intermediate hematite-magnetite-talc-chlorite-apatite alteration zone at Southern Ridge revealed that primary, medium salinity (7.0 - 9.0 eq wt per cent NaCl) inclusions homogenised between 181¦ and 257¦C and primary high salinity (22.8 - 25.9 eq wt per cent CaCl2) fluid inclusions homogenised between 118¦ and 257¦C into liquid. Microthermometric analysis of quartz from quartz-hematite veins from the Southern Batter Fault, Southern Ridge show a complex fluid inclusion history. Primary fluid inclusions consist of: low- and high-salinity H2O-NaCI inclusions trapped at temperatures of approximately 140¦ to 230¦C; vapour-rich inclusions of unknown compositions; and æcomplexÆ salt-rich (Ca, Mg, K and Na inclusions).Secondary inclusions consist of medium-salinity fluid inclusions trapped at temperatures of about 140¦ to 280¦C.A two-stage hydrothermal model is proposed for the formation of both the Southern Ridge and North deposits. Early 1a hypogene alteration involved the release of hydrothermal NaCl-CaCl2-rich (25.5 eq wt per cent) basinal brines (110¦ - 150¦C) from the underlying Wittenoom Formation and directed upward along normal faults and focused within the silica-rich rocks of the Dales Gorge Member, by the shales of the underlying Mt McRae Shale Member and overlying Whaleback Formation. Within the Dales Gorge Member hydrothermal basinal brines migrated laterally within large-scale folds with permeability controlled by shale bands and the NW trending dolerite dyke sets. Fluid rock reactions transformed unmineralised BIF to magnetite-siderite-iron silicate BIF, with subsequent desilification of the chert bands. Stage 1b hypogene involved an increase in temperature of the hydrothermal, CaCl2-rich saline (24 eq wt per cent) basinal brines (250¦ - 300¦C) resulting in formation of hematite-ankerite-magnetite-talc-chlorite alteration and the crystallisation of microplaty hematite. Late stage 1c hypogene alteration involved the interaction of low-temperature (~120¦C) basinal brines with the hematite-ankerite-magnetite mineral assemblage. At the Southern Ridge deposit this process was very intense (ie high fluid flux), therefore resulting in the almost total removal of ankerite and resulting in the increased porosity of the ore. Stage 2 supergene enrichment in the Tertiary resulted in the removal of residual ankerite and apatite and the weathering of the shale bands to clay.

Jan 1, 2005

By Brown N. R

This paper attempts to highlight some of the problems encountered in the economic exploitation of the deeper coal seams by opencast mining methods. The major cost elements of three methods of overburden removal are examined in relation to the overall cost of winning coal from deeper-lying coal seams. The three overburden removal methods examined are dragline stripping and two systems combining dragline stripping with shovels and trucks at varying depths of overburden. A dragline is, undoubtedly, the most cost effective system of overburden removal for depths of up to 30 metres but it is suggested that, when dealing with incremental overburden depths in excess of 30 metres, engineers should consider carefully the possibility of using a shovel and truck operation, or other system, to augment the use of a dragline.

Jan 1, 1986

By Pate W. T

This paper describes the development of a dynamic flowsheet simulator for comminution operations. Object oriented software design allows the handling of multiple ore types, blended into multicomponent feed streams. Software objects have been c

Jan 1, 1998

Gas dynamic phenomena, particularly instantaneous outbursts of coal and gas are problems experienced in gassy, highly stressed coal, both usually the result of depth. Diff- erent mining geometries present different opportunities for seam gas to escape, starting from the virgin condition unaffected by mining and ending with the mining of the coal. The mining of the coal varies from entering a virgin seam cross-measure, heading out into virgin seam, advancing longwall faces into virgin seam and extracting developed blocks from large longwall retreating blocks to small pillars. Each method has its particular gass- iness patterns and particular stress patterns, both changing to some extent with time, and changing as mining progresses. Geological structural anomalies are the cause of gas and stress anomalies, causing in turn greater gas and stress manifestations. Pre-drainage of gas from the working seam not only degasifies the coal but causes it to shrink and so may affect stress as well as gas patterns. Unfortunately prior degasification is not all benefit, and there are some d13- advantages to its use. Also although it is possible to degasify places ahead, gassiness will return if drainage holes are shut down or sealed up and other deleterious aspects may be induced. Research should continue into the problem of instantaneous outbursts of coal and Gas.

Jan 1, 1986

By L Jackson, A Parbhakar-Fox, N Fox

"Characterisation of sulfide minerals (eg pyrite, sphalerite) in historic tailings can assist in determining whether there are economic benefits of reprocessing such materials using modern metallurgical practices. In addition, there are associated environmental advantages if the historic tailings are actively generating acid and metalliferous drainage (AMD). At the Old Tailings Dam (OTD), Savage River, Western Tasmania, 38 Mt of pyritic tailings were deposited from 1967 to 1982; consequently it has been recognised as an AMD source. Long-term management options considered for this site have included the establishment of either a water, hard-engineered or vegetation cover. However, due to geotechnical challenges posed and the lack of success demonstrated by previous pilot studies, these strategies have not been implemented. Instead, resolving the pyrite chemistry can allow for a first-pass assessment of whether reprocessing these tailings is a feasible option as part of a long-term management strategy for this legacy site.Tailings samples (n = 144) were collected across the OTD from up to 2 m depth from five facies (A–E), and four zones (1 to 4; defined by hydrological regime and grain size). These materials were subjected to acid-base accounting (ABA) and mineralogical evaluations to determine their geoenvironmental characteristics. Following this, 26 samples were selected for in-depth laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) investigations to evaluate pyrite chemistry across different tailings facies. The results revealed enrichment of Co and Ni in these materials. Specifically, Co content was up to 3.0 wt per cent, particularly within facies C to E, and Zones 3 and 4. Cobalt is recognised as a critical metal, therefore, reprocessing should be considered as a future rehabilitation option for the OTD, pending resource definition using established codes and practices.CITATION:Parbhakar-Fox, A, Fox, N and Jackson, L, 2016. Geometallurgical Evaluations of Mine Waste – an Example from the Old Tailings Dam, Savage River, Tasmania, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 193–204 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

The Kwademen Au deposit was discovered in 1977- 1978 following a regional geochemical survey carried out as part of a UNDP (United Nations Development Programme) and BUMIGEB (Bureau des Mines et de la Geologie du Burkina) mineral exploration programme. The climate in Burkina Faso is rather dry, with markedly seasonal rainfall averaging 800 mm pa in the Kwademen project area. The relief is low and the drainage poorly developed, so that soil sampling was preferred to stream sediment sampling. Rocks have been subjected to deep lateritic weathering, so that they are transformed into a mixture of Fe-oxides and kaolinite over depths varying between 30 and 40 m. At the regional stage, soil samples (30-40 cm depth) were collected a a 300 x 500 m grid. The Kwademen deposit was indicated by Cu, Zn, Mo and Au anomalies. Subsequently, an area of 9.2 km2 was covered by a detailed geochemical survey by soil (100 x 50 m) and auger sampling. The regional anomaly was fully confirmed, and subsequent drilling intersected mineralized ore shoots, justifying the establishment of an evaluation project led by the U.N.R.F. (United Nations Revolving Fund) in 1983- 1985.

Jan 1, 1988