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By G Yeowart, P D. Munro

The Prominent Hill copper-gold concentrator of OZ Minerals Limited in South Australia was built in 2008 and commenced commercial production in early 2009. It has a design ore throughput of eight million tonnes per year (Mt/yr). While the flow sheet has many items in common with other plants treating ores from iron oxide-hosted copper-gold deposits, the Prominent Hill concentrator also has some unique features. Plant design has been based on a 'template' of the very successful Ernest Henry concentrator. Initial options considered for processing Prominent Hill copper-gold ore are briefly examined as well as potential complications arising from the presence of a considerable tonnage of 'gold-only' material present in the deposit. Metallurgical test work and the subsequent decisions leading to the selection of a conventional crushing, semi-autogenous grinding (SAG) and rougher flotation circuit is discussed. One particular difference with other plants treating this ore type is that metallurgical tests and mineralogical studies identified that rougher concentrate had to be reground to a P80 of 20 - 25 microns or finer for adequate liberation of fluorine-bearing minerals. Subsequent satisfactory separation of fluorine-rich gangue material from the valuable copper sulfides requires highly efficient cleaner flotation to make a commercial quality copper-gold concentrate. Xstrata Technology's IsaMillÖ and Jameson Cell technologies developed to meet similar taxing fine grinding and flotation duties for the treatment of the refractory zinc-lead-silver ores of the Carpentaria-Mount Isa Mineral Province were selected for regrinding and cleaner flotation. Plant design has features aiding ergonomics for ease of operation and maintenance not commonly seen in recent projects with large sulfide flotation concentrators.

Jan 1, 2009

The building is a lofty, well-ventilated one of hardwood frame, with galvanized-iron walls and roof, and consists of five spans running north and south, covering a total length of 236 ft. Each span is composed of nine bays of 1:3-ft. centres, making the total width of the building 117 ft. The refinery is situated conveniently at a distance of 100 yds from the smelters. Through the third span of the building runs a 5-ton electric overhead travelling crane, of a 3-motor type, with a span of 29 ft. The crane runway extends over a railway line, which connects the smelters to the refinery. This crane is llsed for handling bullion, coal, melting kettles, lead pumps, &c. A 3-ton crane of similar type, but with a 50-ft. span, runs through the fifth span of the building and also extends over the railwav line alreadv mentioned. This crane is used to load the soft lead into railway trucks, or to stack lead awaiting shipment in the area covered by the crane's operations.

Jan 1, 1918

By Dawson CF

About 17% of the world's present day oil supplies comes from wells drilled in the continental shelf of some 28 countries. The demand for oil is increasing each year and is expected to quintuple in the next decade. In the same period, the demand for gas will climb to at least 20 times its present rate. In the next decade, the percentage of oil and gas obtained from offshore is expected to rise to nearly half the world's consumption. The offshore oil industry is currently striving to achieve new technological advances in the field of deep ocean operations, especially in face of adverse seas. While the emphasis was put on drilling vessels for exploration, the industry was slow in developing effective offshore construction vessels. Until a year ago, construction vessels were but large barges with construction equipment mounted on their decks. These vessels all shared the same severe limitation: When the sea exceeds a five-foot wave height (and in some cases as little as three feet) the conventional construction barge is forced to suspend operations. In face of an oncoming storm they must run for shelter. Their utilization, therefore, is limited and in rough weather areas, such as the North Sea or the Bass Strait is lower than 50%.

Jan 1, 1970

By Warren R. P

When the original Mount Gunson joint venture, between CSR and United Uranium ceased operations in December 1971, an intensive ex- ploration campaign was launched to prospect for more ore in the Mount Gunson region. This campaign resulted in the discovery of the Cattle Grid deposit. A comprehensive sampling programme proved the existence of 4.6 million tonnes of ore, at a mean grade of 2.4% Cu, calculated at a 1.0% Cu cut-off. The planning and development programme that followed this discovery included not only the mining and metallurgical aspects of the exploration of the deposit, but also the en- vironmental aspects. Preliminary work included data collection with respect to meteorology, soil types, and existing flora and fauna.

Jan 1, 1976

By S Kowalczuk, S V. L Barrett

The potential for adverse surface settlement during tunnelling in soil and rock poses a significant risk to the successful completion of any tunnelling project. Undesirable ground movement may lead to unacceptable level of damage to surface infrastructure, buildings and the environment, resulting in safety concerns as well as causing significant delays and costs to a project. One of the empirical methods which is commonly used to predict surface settlement in the early stages of a project’s development is the volume loss approach as described by Mair, Taylor and Burland, 1996. This method was developed for use in soft ground; however it has also been applied in weathered and soft rock to provide an initial indication of potential surface settlements along a proposed tunnel alignment. This paper presents some initial thoughts on the use of this method in weathered and soft rock and the associated limitations which need to be taken into consideration when interpreting the results. This includes complex weathering profile cases where the strength and stiffness of the ground does not necessarily increase with depth.CITATION:Kowalczuk, S and Barrett, S V L, 2014. Initial thoughts on application of the volume loss approach for estimates of surface settlement due to tunnelling in weathered rock, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 641–646 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

GENTLEMEN, I have to thank you very much for the honour you have conferred upon me by electing me President of the Institute for this year. On behalf of resident members, I have to offer the visitors a very cordial welcome to Mount Morgan, and to tell them that all arrangements have been made to enable them to inspect the mine and works at their own convenience, and to supply them with any particulars they may need.It is very pleasing indeed to see such a large gathering, especially on account of the long journeys many have undertaken in order to be present. The first congress in Queensland, about eleven years ago, was attended by a comparatively small number of members, and a rather long time has been allowed to pass in consequence. The large attendance at this meeting encourages the holding of meetings in Queensland more frequently. Owing to the long distances, and the number of mining centres in Australia and New Zealand, we cannot expect to meet oftener than once in six or seven years in...

Jan 1, 1911

Traditionally trucks have dominated haulage in open pit mines. Only recently have conveyors begun to be used in the long haul and high lift duties of surface mines. Steep angle conveyors are proven versatile systems for elevating or lowering materials continuously at steep angles to 90¦. This paper describes the design of a bucket-type steep angle conveyor that was developed as a joint research project between the Western Australian School of Mines and the Maanshan Institute of Mining Research in China. The steep angle conveyor can be used as a viable option for transporting blocky ore from open pit mines. A pilot conveyor was constructed and tested to determine its technical and operational feasibility. Furthermore, a computer model based on Matlab mathematical modelling software was developed to simulate the performance of the pilot conveyor. The model enabled to determine the design parameters of industry-scale conveyors to yield satisfactory performance. These conveyors become very cost-effective for those mines having large mine lives and depths greater than about 500 metres.

Jan 1, 2003

Geostatistical conditional simulation is a method to assess variability and risk in mineral deposits and the tool has wide potential applications in the iron ore industry. Correct reproduction of multivariate relationships is important in iron ore simulation, especially between Fe and impurities such as Al2O3, SiO2 and P. The turning bands simulation method, using a full model of coregionalisation for multiple attributes, is the main multivariate conditional simulation algorithm used in the Western Australian iron ore industry. This paper discusses the results of a more recent approach using minimum/maximum autocorrelation factors (MAF) to transform and decorrelate the multivariate data prior to independent sequential Gaussian simulation (SGS). MAF-SGS results are compared to those of the turning bands approach in the Yandicoogina channel iron ore deposit (CID), and both methods performed well in simulating Fe, SiO2, Al2O3 and P distributions. Extensive checking of simulations showed that both approaches could reproduce multivariate statistics and spatial continuity of the original conditioning data. Both approaches reproduced the histograms and variography of input sample composites. While the MAF-SGS approach requires additional transformations when compared with the single normal scores transformation required for the turning bands method, MAF requires only that the direct semivariograms be modelled. In contrast, using turning bands with multiple attributes requires modelling a full linear model of coregionalisation, which can be difficult to model because of the need to ensure the model is positive semi-definite. Turning bands may be preferred if there are a modest number of correlated variables allowing construction of a linear model of coregionalisation that adequately models the multivariate behaviour. MAF-SGS is preferable for larger numbers of correlated variables. Both MAF-SGS and turning bands methods performed well in conditional simulation of correlated variables at Yandicoogina.

Jan 1, 2007

By S M. Arndt, D Tyler, F Reusch

Although significant advances have been made in understanding the mechanics of pit slopes, numerical modelling hasnÆt significantly impacted on the reliability of the design process. It is well known that legacy modelling approaches donÆt simulate large slopes well. In recent times, the emergence of very large finite element (FE) models with more than ten million degrees of freedom and the ability to simulate a large number of discrete structures, has allowed a step change in the simulation precision for slopes. The model size allows global and local effects to be realistically simulated in one model for the first time and the process can be better integrated into normal open pit slope engineering processes. Some examples of simulation of very large open pits are shown that demonstrate the challenges and some recent advances in modelling large slope behaviour. Significant limitations in the current measurement and observation regimes of open pits have been identified.

Jan 1, 2007

By Butler I. K, Nicholson P. M

There are four main types of base metal and gold mineralisation recognised in the central Pine Creek Geosyncline. These are stratiform, polymetallic veins, stockwork/concordant gold-quartz veins and unconformity related uranium-gold-platinoid mineralisation. The stratigraphy of the central Palaeoproterozoic Pine Creek Geosyncline has been simplified into three groups comprising the Batchelor, Frances Creek and Finniss River Groups in ascending order. Stratiform mineralisation occurs within the Frances Creek Group. The earliest mineralisation is found adjacent to circular faults ringing basement highs. Higher in the stratigraphy, stratiform mineralisation is often associated with zones of high compression in the vicinity of basement highs. A synsedimentary-diagenetic origin for stratiform mineralisation is proposed. Polymetallic vein mineralisation occurs within the Frances Creek and Finniss River Groups. Its composition changes systematically through the stratigraphy similar to the stratiform mineralisation. The mineralisation is structurally controlled and usually occurs in the vicinity of basement highs. Stockwork-concordant gold-quartz vein mineralisation is hosted by the upper Frances Creek and Finniss River Groups. It occurs within compressional zones and along the Pine Creek Structure corridor around, above and particularly between basement highs. Mineable reserves occur in thick continuous semi concordant quartz-sulphide veins and/or stockworks. Unconformity related uranium-gold-platinoid mineralisation shows a close spatial relationship with the Palaeoproterozoic/Mesoproterozoic unconformity. The mineralisation is localised by structures formed during Mesoproterozoic deposition and is commonly adjacent to Archaean basement or its remobilised equivalents. The type of mineralisation (stratifom/polymetallic vein) is a reflection of local stress regimes, structure and physio-chemical conditions. An initial phase of stratiform mineralisation is postulated to have occurred with the first significant marine transgression in a tensional regime. A second phase occurred later during a compressive regime. "Ihermochemical sulphate reduction of mineralising fluids by hydrocarbons is invoked as the precipitation mechanism for the polymetallic vein type of mineralisation. Hydrocarbon generation is postulated to have occurred within the Frances Creek Group, in many places contemporaneously with the movement of mineralising fluids and basin compression. Polymetallic veins formed from the interaction of mineralising fluids and hydrocarbons which were trapped in suitable structures. An abundant, continuing supply of hydrocarbons was necessary to form significant deposits. Where these conditions were not net, the mineralising fluids largely continued their ascent to the near surface environment to form stratiform deposits. The stockwork/concordant gold-quartz vein mineralisation is a later event and occurred during the relaxation of compressional defonnation after deposition of the 1-inniss River Group.

Jan 1, 1994

A review is given of the development of the author's ideas on the relationship of ore occurrence to regional dislocations in the earth's crust, presently identifiable in particular areas as linear discontinuities in patterns of geological and geophysical data. Ideas originating from field observations in Broken Hill were developed in conjunction with three-dimensional kinematic deformation models which were devised to simulate rock structures, and to illustrate their response to assumed linear and planar movements at the scale of mine and regional geology. These led to the study of linear features in the pattern of Broken Hill district geology, and to the observation that the Broken Hill lode occupies a "cross-roads" position at the intersection of regional geological lineaments where they cross through and deflect the host rocks. A genetic association was therefore proposed. The recognition of significant regional lineaments requires special techniques and treatments of field data originally developed for the Broken Hill situation. The subsequent application of the work to the Western Australian shield revealed that known major nickel and gold deposits also occur where the host rocks are crossed by one or more regional lineaments. These lineaments were recognised as part of a continental tectonic pattern of major linear trends with which major ore deposits are associated. The ideas were later used in exploration leading to the discovery of the Olympic Dam deposit at Roxby Downs, South Australia, which is related to regional lineaments.

Jan 1, 1983

By McGhie R. R

The general structural features and the principal mineral relationships of the Black Star ore body, Mount Isa, Queensland, have been described in several previously published papers. But particular reference may be made to the work of Grondijs and Schouten, whose examination of over 200 polished sections revealed some remarkable features in the process of ore deposition. The observations by the present authors are based upon the study of a smaller ·set of specimens complementary to those examined by Grondijs and Schouten and are intended to elaborate certain aspects of the mineral relationships, more particularly those affecting the ore-dressing processes.The work described applies to the primary sulphide ore only, and to the present milling practice of fine-grinding and selective flotation.GEOLOGICAL FEATURESThe Black Star is one of several economic mineral concentrations in the Mount Isa series of thinly bedded carbonaceous shales, which are considered to be of preCambrian age. The nlineralization is apparently connected with pegmatite intrustions located within some miles of the ore bodies, and has been Gontrolled in the main by major folding of the shales and by a shear system which follows approximately the strike and dip of the beds. The detailed "The investigations described in this paper were made in the Metallurgy Department, University of Melbourne, where the senior author was formerly Senior Lecturer in Mining and Metallurgy. A report on a section of the work was submitted by the junior author as a thesis requIred by the University of Queensland.

Jan 1, 1939

By Marwick PL

As part of its operations Hamersley Iron operates a heavy medium Concentrator to upgrade low grade, unsaleable iron ore to produce saleable lump and fines products. Firstly, the attempts at delivering a blended feed in both chemical and physical characteristics are presented. Improvements in blending controls are shown to have given process performance improvements. Secondly, improvements to the feed preparation section are detailed. These alterations are providing a much cleaner feed to the subsequent processing stages.

Jan 1, 1987

Grade control plays an essential role in the good running of a mine. The factors at play are many, starting from a good analysis of the geology and a correct sampling procedure. Once this is achieved (and it is an essential prerequisite), the problem is to adequately define what is ore and what is waste. This paper tries to show, through a small example, how simple geostatistical techniques (variography, and moving average or kriging), can help in accurately defining these limits in a geologically homogeneous zone, thus allowing optimal use of the available information.

Jan 1, 1987

A variety of algorithms and methods are being used by the mining industry today to map mineral resource for reserve estimation. The traditional methods including Polygonal, Sectional and Inverse Distance methods are relatively easy to understand and implement. They have served industry well for several decades and should continue to do so for the large bulk mineable deposits with very regular geometries with relatively small variation in grade.

Jan 1, 1992

By White L. R, Boger D. V

The paper describes the surface chemistry and particle physics that control the fundamental flow properties (Theology) of mineral particle slurries. We further address, through a series of case studies, the design data that emerges from experimental studies of the flow properties of complex, high volume fraction mineral slurries. The case studies are drawn from mineral oxide concentrate processes, tailings dewatering operations and from filter cake production and management. The paper emphasises the essential links between design of process slurry handling systems and the control of the flow of such slurries by control of the pulp chemistry.

Jan 1, 1992

By G E. Holt

Active EM subsurface imaging is a proprietary technique developed by Marschall Acoustics Instruments Pty Limited (MAI) to image subsurface features at depths useful for the mining industry. Similar in field operations to high resolution seismic surveying, the Active EM technique employs electromagnetic energy rather than elastic wave energy. Received backscattered energy in the Active EM technique is thus due to differences and contrasts in electromagnetic permeability and permittivity in the subsurface, analogous to LamTÆs constants in elastic wave imaging. Carrying the analogy to seismic imaging even further, the Active EM method employs high power transmissions of very wide-band coded signals of a controlled polarisation. Likewise, the array pattern and polarisation of the receiving transducers is also tightly controlled. Thus, in a certain mathematical sense, Active EM is the electromagnetic equivalent of high power high resolution vibroseis seismic surveying. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By D R. Rankin, J J. Fuykschot

Forrestania Nickel Mines is owned and operated by Outokumpu Mining Australia Pty Ltd and is situated 400 km east of Perth, WA in the Forrestania Greenstone Belt. Production started in late-1992 at a rate of 600 ktpa and reserves were exhausted in August 1999. Cosmic Boy is the largest of three mines worked and operates in a high stress environment with both very high and very low rock mass strength domains. Stoping commenced in 1995 using conventional benching with long hole slot rises but because of drilling and blasting problems the mine switched to airleg rising. In 1997 the mining method was changed to smaller scale up hole retreat benching with each stope requiring a slot rise of up to 16 m length. This method does not allow top access to the rise location and so airleg rising was used until mid-1998. At this stage mining was approaching areas of higher stress for which it was clear that an alternative to this entry method of rising was required. Small diameter raise boring and Cubex rigs were considered but because of the set up costs were not considered to be viable. Since the ore is relatively soft, burn cuts were developed to make use of specially designed 152, 203 and 254 mm diameter reamer bits (depending on the rise length) and drilled with conventional long hole drilling equipment. These rises are fired in one blast together with the slot rings. In the northern lower section of the mine (below 400 m) the principle stress has been estimated at 60 MPa and this causes minor strain bursting in BIF development headings and loose material to form on walls and backs. Trials of destress blasting modelled on Canadian experience has greatly reduced strain bursting at the face. However only around 300 m of development was affected and so this method had not been optimised when mine development was completed.

Jan 1, 1999

By H Holmstr÷m, A Widerlund, M Lindvall

At the Kristineberg mine in northern Sweden sulfide-rich, poorly buffered tailings have been deposited in five impoundments located along a valley. The tailings area has been remediated by applying a combination of till cover and flooding. A new method that has been applied to parts of the tailings area is to raise the groundwater table to saturate the tailings. By increasing pH by liming, thereby reducing metal mobility, a water-covered downstream impoundment is functioning as a trap for metals released from the till-covered impoundments upstream. In this paper the efficiency of the system approach used at Kristineberg is evaluated. Progressive changes of water quality from groundwater in the upstream till-covered impoundments via surface streams within the pond system to the water in the flooded downstream pond and its outlet are described. The results show that the system approach used in the design of the remediation programme of the tailings works as planned. The sulfide oxidation rate has decreased in the till-covered impoundments, and, as predicted, there is an out-flush of old weathering products which will continue for at least five years before equilibrium is reached. The groundwater in the till-covered impoundments has high concentrations of Fe, S, Mg and Zn, but the concentrations of metals such as Cu, Cd and Pb are much lower than before the till cover was applied. The limed pond is an efficient metal trap, with concentrations as high as 2.76 per cent Zn and 0.28 per cent Cu in the calcite-gypsum sludge developed on the tailings. The outlet from the flooded pond, and thus from the whole mining area, releases small amounts of metals to the recipient in comparison to the amounts that are in movement within the mining area. During the period May to November, 13 kg dissolved Zn and 111 kg particulate Zn was released to the recipient, whereas a total of 27 000 kg was transported by surface water within the impoundment system during the same period. The results from Kristineberg show that when planning remediation of complex mining areas, it is useful to adopt a system approach in which different methods are used on different parts of the area along the flow path of the drainage water, whereas flooding of the downstream pond is the key to the performance of the entire system.

Jan 1, 2003

By Parker C. J, Mikula P. A

The excavation for the Sydney Opera House Parking Station comprises a large donut shaped underground cavern with a central sandstone pillar. The maximum effective roof span is about 19 m and the rock cover is between 7 m and 8 m. Permanent support for the roof and the various services tunnels consists of a combination of tensioned anchors, and untensioned dowels, and mesh with shortcrete and fibrecrete as the final lining. Steel sets were installed at main intersections.Fundamental to the design philosophy for excavation of these spans at such shallow rock cover was the use of monitoring to check on the adequacy of the installed support. Prior to excavation, extensometers, inclinometers, piezometers and surface settlement survey stations were installed. Underground survey stations, anchor load cells and shotcrete pressure cells were installed as excavation proceeded. Excavation commenced at the crown using an initial heading and three widening stages. Geological mapping during excavation confirmed borehole expectations, namely sandstone beds 1 to 4 m thick interbedded with thin shale units. Bedding plane contacts varied over short distances from tight partings to thick brecciated seams. Jointing was subvertical and joints tended to be bed-limited.

Jan 1, 1993