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By J L. Mauk

The Sovereign, Jubilee, Scotia and Jasper Creek prospects occur in an area of ~3.0 km by 2.5 km (~7.5 km2) in the Hauraki goldfield. The prospects are hosted by andesitic to dacitic flows, autoclastic breccias and localised pyroclastic and air fall deposits. Jubilee and Sovereign prospects lie along the northern and southern parts of the Waitekauri Fault, respectively, whereas Scotia is located ~1 km to the E, and Jasper Creek a further ~1.2 km to the ENE. Wall rocks are typically intensely altered, although the degree of alteration becomes more variable east of Scotia and at Jasper Creek. Alteration minerals include quartz, adularia, albite, chlorite, pyrite, illite, interstratified illite-smectite, smectite and calcite. Several of these minerals have distributions that show distinct zonation with adularia most abundant at Sovereign and Jasper Creek, but restricted to shallow levels at Scotia. Illite occurs throughout Sovereign and Jubilee plus the western margin of Scotia where it grades into interstratified illite-smectite; smectite predominates at Jasper Creek. Veins are uncommon and typically narrow, but show distinct zonations. Quartz veins are more abundant at Sovereign and Jubilee, whereas calcite veins are more abundant at Scotia and Jasper Creek. Laumontite veins occur at Scotia, and rare clinoptilolite, mordenite and stilbite veinlets with calcite occur at Jasper Creek. Fluid inclusion in quartz and calcite homogenised between 141¦ to 272¦C and trapped a dilute solution with an apparent salinity of less than 2.6 weight percent NaCl equivalent. Homogenisation temperatures are hottest at Sovereign (average 241¦C) and Jubilee (average 239¦C), cooler at Scotia (average 204¦C) and coolest at Jasper Creek (average 162¦C). Calculated paleowater table elevations suggest the water table was 680 m to 750 m above sea level at Sovereign and Jubilee, 450 m at Scotia and 225 m at Jasper Creek. The current data suggest three scenarios that can explain why Sovereign and Jubilee are deep and hot, whereas Jasper Creek is cool, shallow and marginal; 1.   some or all of the prospects may represent separate overlapping hydrothermal system, 2.   a high-relief hydrothermal system on the side of volcano with an inclined water table and outflow towards Jasper Creek, and 3.   a low-relief hydrothermal system that has been either tilted or block faulted with greatest uplift and erosion to the west.

Jan 1, 2005

Triboelectric Separation - Beneficiation of Coal The performance of triboelectric separators is highly sensitive to the selectivity of the particle charging process. This paper presents a quantitative study on triboelectric coal beneficiation. The performance of different charging media was studied. Stainless steel was identified as having a work function between that of coal and silicate gangue and found to be the optimum charging medium for coal beneficiation. Recent results from separation tests were performed where silicate gangue was separated from crude coal using a parallel plate free-fall separator are illustrated.

Sep 13, 2010

The prospect of utilisation of phosphate ores which contain high P2O5 values associated with Al and Fe has produced a great deal of interest over many years. Processing options have generally been based on the utilisation of by-products which were required to offset the processing costs.   This paper presents a range of processing options which have been investigated at laboratory or technical scale on phosphate ores which predominantly consist of crandallite, CaAl3(PO4)2(OH)5.3H2O and millisite, Ca(NaK)Al6(PO4)4(OH)9.3H2O. Christmas Island (Indian Ocean) and Mt Weld (Western Australia) phosphate ores are good examples of such feedstocks. It is expected that these processes may also be applicable to such phosphate ores from other locations.

Jan 1, 1990

The Mahakipawa gold deposit is located 21 km northwest of Blenheim. It became the site of a small hardrock gold rush in 1889 following nearby alluvial gold discoveries in 1888. The study investigates the geology of the area of hard rock mining in the vicinity between Cullens and Waikakaho Creeks. The Marlborough Schist which hosts the gold depos, it consists of polydeformed greenschist facies quartzofeldspathic psammitic, pelitic and volcanigenic schist.

Jan 1, 1993

By N F. Fraser

Seafield ResourcesÆ offshore placer gold project covers c.10 000 km2 of the Westland continental shelf between Karamea and Jacksons Head, from the low-water mark out to the 120 m isobath (Figure 1). De Beers Marine (DBM), the marine diamond subsidiary of the De Beers Group, will carry out the project with geological input from Placer Solutions (PSL). DBM bring a wealth of expertise and advanced technology to the project, developed during their 20 years of exploration and mining of diamond placers on the Atlantic shelf of southern Africa, where they have also maintained a strong environmental record.   Glaciers and high-energy rivers emanating from the Southern Alps have transported substantial quantities of gold bearing sediment onto the Westland continental shelf during Pleistocene glacial periods, when fluvial gradients are steeper, sea level is c.120 m lower and most of the shelf is exposed. These deposits have been extensively reworked by the advancing shoreline and marine processes during interglacial marine transgressions, and most are now buried beneath a variable thickness of post-glacial marine sand, silt and mud. DBM will use side-scan sonar, swath bathymetry, Chirp sub-bottom profiling and a magnetometer to map the sea floor and sediments beneath it, guided by PSLÆs predictive geological model for gold distribution on the shelf. Cactus grab and vibro-core samples will be used to ground-truth the geophysics and provide stratigraphic, sedimentological and gold distribution data for incorporation into the geological model. Areas of interest identified by the geophysical and sampling data will be investigated in more detail, with closer-spaced geophysics and Mega-drill sampling to a maximum sediment depth of 20 m beneath the sea floor. These samples will be raised to the ship with air-lift suction technology, processed onboard for mineralogical and grade information, then returned to the sea floor. Environmental baseline data will be gathered from Van Veen grab samples of seabed sediment taken throughout the area during the prospecting programme.

Jan 1, 2005

By T Casten

Freeport IndonesiaÆs DOZ (Deep Ore Zone) mine is scheduled to commence production in the second half of 2000. The DOZ will produce 25 000 tpd using mechanised block cave mining methods and will have a number of major improvements when compared to previous block cave mines in the district. The DOZ will have an independent and improved ventilation system, a flexible and efficient truck haulage system, and a more reliable crushing and conveying system than in previous underground mines in the district. This paper will describe the mine plan, haulage, and ventilation systems, and compare them to those used in other operations in the district.

Jan 1, 2000

By E Jak, M Shevchenko, E Nekhoroshev, D Shishin

In the field of pyrometallurgy, the presence of multiple molten phases with distinct chemical compositions, such as slags, mattes, speiss liquids, metals and molten salts, is a well-known phenomenon. These phases exhibit strongly non-ideal solution behaviour and are mutually miscible to varying degrees. To describe these complex molten liquids, the Modified Quasichemical Model (MQM) has proven effective and has been applied to numerous binary, ternary and several higher-order multicomponent systems related to pyrometallurgy. In recent decades, the complexity of high-temperature processes has escalated due to increased impurity concentrations in primary ores, the incorporation of recycled consumer products and the integration of metallurgical plants through by-product and waste exchanges. To address these issues, PYROSEARCH laboratory has been developing large 20-component thermodynamic database using a generalised CALPHAD (CALculation of PHAse Diagrams) methodology integrated with experimental investigations. Over the past decade, strategic decisions were made balancing the ability to generate experimental data, prediction power, accuracy, stability of calculations, as well as computational time, which are discussed in the paper. Examples provided for issues of >3 liquid immiscibility, non-ionic behaviour and exaggerated ‘sharp’ enthalpies of mixing in silicate slags, dealing with multiple oxidation states, as well as comparative analysis of pair and quadruplet approximation in MQM.

Aug 21, 2024

By R Dwyer, S Rea, W J. Bruckard, N McSweeney, R Holmes

"The innate ability of microorganisms to adapt to changing or inhospitable environments has often been exploited for industrial purposes and forms the basis of many current biotechnological processes. The ability of bacteria to adapt and adhere to specific mineral surfaces ensures that the energetic or nutritional requirements of the cell are met and often serves as a survival mechanism under unfavourable?growth conditions or conditions of stress. In this process, cells may rearrange or modify the macromolecules expressed on the cell surface itself or produce extracellular molecules, modifying mineral surfaces to render them more suitable for growth. The modifications that these molecules produce on mineral surfaces may result in changes to the surface charge and hydrophobicity of a mineral. As a result, these biomolecules may have some potential application as flotation collectors or modifiers.In this work, the effect of long-term exposure of Paenibacillus taiwanensis to goethite and common gangue minerals associated with Australian iron ores on the differential expression of membrane and extracellular proteins was determined. Both groups of proteins play a role in cell adherence to mineral particles. Cells were adapted to grow in the presence of each mineral over time. The proteins expressed on the cell membrane and the extracellular proteins excreted by the cell were isolated and analysed by two-dimensional polyacrylamide gel electrophoresis (2D gel PAGE). The outcomes of these studies are presented here and potential application of these products for flotation discussed.CITATION:Dwyer, R, Rea, S, McSweeney, N, Bruckard, W J and Holmes, R, 2013. Microbes and their metabolites - potential iron ore flotation reagents, in Proceedings Iron Ore 2013, pp 369-372 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

The selection of Sydney and Port Kembla for the First Ordinary Meeting of the Institute for 1938 was, no doubt, a recognition of the celebrations marking the 150th Anniversary of the first settlement of this country. In selecting a theme for my Presidential Address, I propose to depart from the precedents of my distinguished predecessors, as I feel that this year of celebration is the natural year for a brief review of the history and progress of the Institute.In July, 1892, the Amalgamated Mining Managers' Association of Australasia held its Annual Conference in Ballarat, Victoria, when Mr. Uriah Dudley, who attended as a delegate from Broken Hill, brought forward the advisability of the formation of an Australasian Institute of Mining and Metallurgy. Mr. Dudley was authorised to take such action as he thought fit, and the result was the formation of a Provisional Committee in Broken Hill of men who were mostly members of the American Institute of Mining Engineers. Broken Hill was therefore really the birthplace of the Institute.A circular headed Broken Hill, September, 1892, with the signature of Uriah Dudley, Acting Hon. Secretary, Provisional Committee, which was sent to those likely to take an active part in the formation of an Institute, read as follows:-The Mining Managers' Association of Australasia has suggested that the time has now arrived when an Australasian Institute of Mining Engineers should be established, having objects similar to the American Institute, of which all of the Thirty-one Colonial...

Jan 1, 1938

The Hishikari gold deposit, discovered by the Metal Mining Agency of Japan, has become a giant class epithermal gold deposit with the highest grade of gold yet recorded in the world through detailed exploration and development by the Sumitomo Metal Mining Co Ltd. The exploration strategy involved a regional approach combining geological and gravity surveys over a 900 km2 area which had historically produced over 120 t of gold. These surveys were carried out to grasp the common geologic features of epithermal gold deposits in the survey area. A genetic model for epithermal gold deposits in the area under regional survey was also considered based on detailed research of the Kushikino epithermal gold deposit which was in operation at that time. This model was applied to the targeted areas, and important relationships between mineralisation, host lithology, intensive propylitic alteration and gravity highs became apparent. The Hishikari block was selected in this way and bonanza gold was discovered during drilling. Since the development of the Hishikari mine, information useful for further exploration for the same type of deposit has been accumulated.

Jan 1, 1995

Ledcap Pty Ltd has developed two software tools for assisting in the determination of life-of-mine (LOM) trucking requirements. The first tool generates haul paths and the second calculates truck travel time over these paths. The two step approach allows the paths to be viewed and if required edited, to better represent the actual site haul routes.The first tool automatically creates haul paths between the mine bench and the dump. To do this the user supplies a master haul route and a scheduled block model. The master haul path and the block model are interacted to create multiple haul routes, one for each pit/dump bench pair in each scheduling period. Each path carries with it a record of the scheduling period it represents and the dry tonnage hauled over the path in that period.The second tool calculates truck travel time over the path. Data from the manufacturer's rimpull and retarder curves are used to calculate accelerations and speed over each segment of the haul path. As the paths are derived from digitised representations of mine haul routes the path f les often have over a hundred segments. This detailed representation of the haul route allows the software to automatically adjust speed for different radius corners and accurately simulates the changing accelerations over the gradient changes that occur in real life mine ramps. Rolling resistance can be specified at a global level, at a segment level and at a period level. This allows rolling resistance to be changed seasonally as well as spatially.Life-of-mine trucking studies attempt to calculate an accurate answer from extremely variable inputs. This paper will detail the features of the two software tools and how the tools provided in the software can assist the mine planner to have greater confidence in their life-of-mine trucking requirements and the subsequent production capacity inputs to their scheduling calculations.

Dec 6, 2010

By N Phillips

Fosterville gold mine recently celebrated production of its one millionth ounce of gold based firmly within a history of refractory sulfide gold mining. Compared with other Victorian gold mines, the disseminated nature of the sulfide gold is a deposit style with low estimation variance combined with established processes to accurately delineate the controlling structures. The systems in place had been established and have worked effectively for the majority of the one million produced ounces.By the end of 2014, diamond drill campaigns targeting the lower Phoenix orebody at depths of 800 m below surface began showing a change to the nature of the gold within the deposit. Coarse visible gold within 0.5–2 m thick quartz carbonate veins were being intersected with regularity showing the emergence of a different zone of gold mineralisation.Data about the new and exciting discovery couldn’t be gathered fast enough, however, established systems and processes throughout the geology and processing departments were not developed to handle a coarse gold environment. Change would be commensurate with the size and scale of the discovery, and new learnings would need to be implemented quickly to keep in front of a mining schedule that was focused on producing tonnes due to the dropping grades of the sulfide ore.Gold assays being returned were showing that the gold nature was different to those of other Victorian deposits. Comparative to the highly nuggety nature of gold found in other Victorian goldfields, the fine grained gold accumulations were dispersed in relatively consistent narrow linear trends grading consistently into the hundreds of grams per tonne. New drill intersections were being returned by the day and research to find developed orebodies that had published information into how to handle such a rapid change yielded few examples.The challenge was to review and set new standards with regards to handling an orebody that transitioned the very nature of the gold being mined. This involved reviewing all steps in the estimation process including data capture and quality control and quality assurance through to mineral liberation through the mill. Difficulties also involved finding analogous orebodies that consisted of both free milling and refractory ores that were dealing with drill assays that were measured as percentages of gold.CITATION:Phillips, N, 2017. Fosterville gold mine – breaking the mould for Victorian gold, in Proceedings Tenth International Mining Geology Conference 2017, pp 393–400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By J Player, G Sweby, S Webber, E Jones

Seismic systems are a tool for the monitoring and forecasting the rock mass response to excavation. Common issues encountered at mine site audits and reviews are: how to design an effective seismic system, implementation of the design, interpretation of seismic source results and understanding the reliability of the seismic source. These issues are often a function of several items including: • Experience of site personnel in undertaking seismic system design. • Personnel not envisioning multiple phases of system expansion to understand system robustness issues. • System design/expansion occurring in response to damaging seismic activity rather than planned expansion of a system • The mine access development is often localised in comparison to the total orebody being mined hence, planning sensors in longholes in advance of development rather than in short holes close to development will improve the three-dimensional aspect of the network. • Limited site processing of the seismic event data, hence engineers do not see the uncertainty associated with event location, size, source and system layout. Mine site users require a framework to appreciate the challenges and limitations in locating large events. For example, event locations are given as precise measurements (to the nearest centimetre) whereas the volume of deformation resulting in the event often has dimensions of tens of metres or more (as defined by the source radius). A stronger awareness of the uncertainty of rock mass yield within large seismic sources will assist site users in the interpretation of rock mass damage. The encountered design and implementation errors are reviewed and discussed with a practical set of rules presented to provide a robust seismic system that provides consistent results and increases the user’s understanding of uncertainty in source location and size. The authors’ experience across multiple mine sites, seismic systems and damaging seismic events over a 30 year period has been summarised into practical rules for site personnel of all experience levels.

Nov 29, 2022

By M Amanzadeh, S M. Aminossadati, B M. Masum, M S. Kizil, C R. Leonardi

Gas sensing systems are becoming more important in many industries such as oil, gas and mining operations. Particularly in underground coalmines, accurate and reliable monitoring of toxic and combustible gases such as methane, nitrogen dioxide, carbon monoxide and hydrogen sulfide is essential. Available conventional electrochemical sensors for gas measurements in underground coalmines suffer from shortcomings such as cross-sensitivity response, limited lifetime, high calibration cost, maintenance cost and safety. Recent studies have found that fibre optic-based gas sensors have potential to eliminate these issues. These sensors can also be used for long distance and distributed sensing of various gases, both of which are important for underground gas monitoring. The aim of this paper is to review the present underground mining gas monitoring systems and review the new generation of fibre optic-based sensing systems for use in underground coalmines.CITATION:Masum, B M, Aminossadati, S M, Leonardi, C R, Kizil, M S and Amanzadeh, M, 2017. New generation of gas sensors for underground coal mining applications, in Proceedings Australian Mine Vent Conference 2017, pp 189–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By B Clemen, D Gordon, F Cesnik, P Griffin

In March 2002 Newcrest Mining Ltd commissioned a 4 Mtpa gold-copper concentrator at its Cadia Valley Operations in New South Wales. This paper presents the design and construction considerations, commissioning and ramp up issues related to start up of the concentrator as well as current performance and future expansion plans. Commissioning of the plant was the culmination of six years of project planning, from discovery of the resource during the Cadia Hill drill out campaign in November 1996 to project implementation and plant operation. Current resource estimates stand at around 50 Mt with an average grade of 2.4 g/t gold and 0.8 per cent copper. At current processing rates the project life is expected to exceed ten years. The processing plant comprises a 9.75 m (32 ft) diameter Fully Autogenous (AG) mill, a single 6.7 m (22 ft) diameter ball mill, pebble crushers, gravity gold recovery circuit and flotation plant. Upgrades to the existing infrastructure and manning requirements at Cadia will be discussed as well as the resultant impacts on operating costs for the operation. The processing plant was expected to deliver 290 000 ounces of gold and 30 000 tonnes of copper in concentrate in its first full year of operation and progress against that goal will be presented.

Jan 1, 2003

By Madgwick J. C

Microaerobic biodegradation oflow-grade manganese dioxide slurry tailings was demonstrated in enrichment cultures treated with dilute molasses at 30°C and pH 5·8. Supplementary nitrogenous nutrients, yeast extract addition and pH adjustment were not required.Continuously stirred, air-limited reactors were superior to still intermittently agitated cultures, in that, at 5 per cent (w/v) MnOz tailings and 5 per cent (w/v) molasses, the yield of 0.12 g Mn++/g molasses, the rate ofleaching of 1·06 g Mn++/l/d and a recovery of Mn++ of 58 percent from MnOz were 2·8 times, 1·7 times and 1·9 times greater, respectively. The best compromise in yield (0·45 g Mn++/g molasses) and rate ofdissolution (0·73 gMn++/l/d) was at 1 per cent (w/v) molasses in a stirred reactor.Where leaching organisms were separated from sterile ore by a bacteria impermeable membrane leaching was shown to be some 20 per cent due to diffusible metabolites and 80 per cent due to a direct contact between the bacteria and the ore particle's surfaces.

Jan 1, 1986

By D Rubery, C Croker

The Boddington Gold Mine (BGM) is located 120 km south east of Perth, Western Australia. The operation is managed by Worsley Alumina Pty Ltd and mined by contractor Henry Walker Eltin (HWE). The mine has been operating since 1987 with ore extracted from a series of pits along strike. Ore is contained within the basement rock, which is overlain by a cap rock layer and transition zone. Cap rock and basement zones require blasting.As the mine neared completion, a high-grade deposit was discovered within 50 m of an existing Western Power substation and 100 m from the processing mill. The substation provides power to the Boddington area and is a back-up power supply to the city of Perth. Due to the delicate nature of the transformers located at the power station, overhead power lines and the mill, blasting in the area was considered very high risk. As such blasting needed to be controlled for flyrock, airblast and most importantly peak vibration and frequency limits which had the potential to damage the transformers.The mine was due for closure in March 2001. The decision to mine the pit was based on its high grade, ability to be blended with lowering grades from other pits and changing of the processing technique with the expansion. This decision extended the life for a further six months.Due to the high potential risks a detailed risk assessment was conducted by Orica, Worsley and Henry Walker Eltin. The completed assessment and the major design parameters were presented to Western Power for approval. The ability to reduce the blasting risk was focused on limiting of vibration through controlling maximum charge initiated per delay, blast timing and firing direction, and other innovative control measures. OricaÆs SHOTPlan« and Sabrex« computer modelling packages were used to predict the outcome of blasts.The success of this project has opened the doors for other high risk blasting projects, which otherwise may be left unmined.

Jan 1, 2002

By Cawte D. C, Just G. D, Whitchurch K. D

The stringent marketing specifications included in coal contracts mean that coal producers must supply cleaner and more consistent coal than may have been formerly required. Geostatistics has the potential to aid in the accurate estimation of the washability characteristics of coal. A prediction method, the Kriged Service Variable Approach has been developed.A Computer Aided Drafting and Design system has proved useful in the development and application of the approach. The geostatistical approach has been tested against coal geological and borehole data and applications discussed.

Jan 1, 1987

Delivery of effective plant shutdowns is primary to the business success of mining and processing plant operations. This paper sets out a methodology that starts with understanding the business objectives of the shutdown and promotes rigorous detailed planning, effective communication, appropriate governance and effective participation of plant operations personnel. The result is delivery of business effective outcomes.

Jan 1, 2004

A fundamental component of grade control at Tarmoola Mine has been the monitoring of assaying through quality assurance programs. The programs have concentrated on issues related to accuracy and precision of leachwell and fire assay techniques, sample preparation and grade variability within a sample. An outcome of monitoring has been identification of shortcomings in the application of assaying techniques to Tarmoola ore types that contain coarse particulate gold. Leachwell has shown satisfactory precision since introduction as the primary assay technique in October 1998 but leachwell accuracy and recovery through comparison with fire assay techniques has identified bias. A bias toward higher fire assays in grades above 2 g/t invoked an investigation into the cause of the discrepancy between leachwell and fire assay. Testwork evaluated Leachwell assay recovery by varying leach time duration, which showed that by increasing the leach time improved recovery significantly. Monitoring of leachwell against fire assay had shown that a leachwell (200 g) with a one hour leach has under-called grade when compared with fire assay by up to 18 per cent, on average, for Tarmoola ore types. Alternatively, optimisation of the leachwell assaying technique using a 200 g pulp and a two hour leach has returned, on average, higher assays than fire assay by up to eight per cent. Testwork on screen fire assays, duplicate assays and fire assay to extinction has demonstrated assay variability associated with coarse, particulate gold. The variability and distribution of gold in Tarmoola ore types has emphasised the importance of high quality sample preparation for leachwell assaying to ensure liberation of gold to leaching solutions. Assay quality assurance protocols are vital to assay data integrity and enable confidence in delineation of ore-waste boundaries and provide early recognition of problematic assaying periods and isolation of grade control practices, which depart from performance standards critical to the operation.

Jan 1, 2000