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By J Taylor, M Smith, A Tunnadine, D Nikolakopoulos

As Olympic Dam rapidly expands into the Southern Mine Area (SMA) the Mine Geology team has concurrently ramped up underground diamond drilling to sustain rates of above 175 km/a. With >10 underground rigs double-shifting, traditional paper sections used for the management of drill programs were no longer optimal due to scale of operations. An opportunity was identified to modernise monitoring of all underground diamond drill programs, through the integration of logged copper sulfide estimates with Olympic Dam’s first-fully integrated deposit-scale geological model in Leapfrog Geo. This paper describes the transition within the Mine Geology team from reliance on 2D paper sections, towards near-real time 3D geological modelling for optimising end-of-hole decisions in the field. This transition was enabled by innovative database solutions informing locally constrained implicit models, limited by a distance buffer around active underground fan drilling. Due to the high volume of historic drilling, there were significant computational challenges with the implementation of daily production style implicit models at Olympic Dam and initial testing of regular updates to implicit gradeshells and sulfide domains required in excess of 12 hrs to run. The enabling solution was to optimise the interfaces between the AcQuire database, Deswik MDM and Leapfrog Geo to create a dynamic, streamlined workflow that was easily completed by Mine Geologists in accordance with daily production duties. Geologists are now building rapid implicit models for a range of variables from an integrated data set of logged sulfide estimates and existing assays, spatially constrained by 150 m buffers around active drilling using a unique drill fan identifier flagged during the planning phase. Once the live-implicit models are updated, they are exported for visualisation on field tablets to be used during logging and core checks at the start and end of every shift. To manage the risk of ‘going digital’ interpretation remains at the forefront of the drill section close-out process, with Mine Geologists critically reviewing the finished sections on a standardised template with new learnings wireframed and communicated to stakeholders. The Live Field Model has enabled a step-change in the geological effectiveness of diamond drilling, reducing over – and under-drilling ore-waste at Olympic Dam continuing to push drilling effectiveness towards 20 per cent of intercepts >2 per cent Cu. In addition, upside or risk identified during the proactive management of drilling execution can be rapidly capitalised or mitigated.

Mar 22, 2022

By A Litwinowicz, M Laxman, A Fourie, A L. Li

This paper presents a design approach and analytical methods that were used for assessing the potential of static liquefaction and developing the mitigation measures for a tailings dams. The rigour of the design and analysis approach represented leading practise in the industry to address static liquefaction, which contributed to a robust design with high confidence and certainty. The salient features of our approach to static liquefaction included geotechnical investigation and tailings characterisation, static liquefaction screening assessment, static liquefaction triggering analysis, limit equilibrium analyses and numerical modelling of static liquefaction using the NorSand model, which was amongst the first tailings dam projects involving numerical modelling of static liquefaction using these methods.

Jul 1, 2021

By L Gobbo

X-ray diffraction (XRD) provides useful information about the composition of an ore sample in terms of quantification of crystalline phases and amorphous content. The use of new, fast detection systems implemented in CubiX FAST industrial diffractometers creates the opportunity to use this technique in exploration and modern process control. Besides the chemical composition of iron ores, their phase composition is also an important factor for exploration, quality control and processing. In the analysis of iron ore, XRD can identify the phases containing iron, such as haematite Fe2O3, magnetite Fe3O4, and goethite FeO(OH), and any other mineral phases present, especially silicas. Quantitative analysis is possible by various classical methods such as straight line or polynomial calibration with standards, but modern quantification analysis techniques such as Rietveld analysis or full pattern autoscale analysis are attractive alternatives, as they do not require any standards. These methods offer impressive accuracy and speed of analysis. Another analysis technique offering great benefit to ore exploration and process control is cluster analysis. This technique greatly simplifies the analysis of a large amount of data, eg from drill core samplings, and automatically sorts closely related scans of an experiment into separate clusters and marks the most representative scan of each cluster as well as outlying patterns. This can facilitate multi-dimensional compositional mapping of ore deposits, identifying regions of favourable mineral composition and allows fast and reliable tracking of the process. It is the most economic procedure to have automatic data evaluation without involving any dedicated personnel in the process. Details of the techniques used, sample optimisation methodologies, results, data precision and limitations will be discussed. The approaches have enormous potential as an inexpensive, reliable tool, useful in the characterisation of iron ore materials in an industrial environment.

Jan 1, 2009

By D Blair, T Scutts, L Fergusson

This paper presents a waste rock treatment and rehabilitation program conducted at a metaliferous mine site in northern New South Wales from 2000–2013. It updates findings from 2005 for Program #1 (which examined acidity, leachable metals and tree growth in a control and three treated areas of waste rock) and includes new results for Program #2 (which examined acidity, plant uptake of metals and trace elements and tree growth in a control and four treated areas compared to undisturbed background levels) and Program?#3 (which examined the treatment and revegetation of submerged mine tailings and an exposed tailings beach).Program #1 showed low soil pH in the control area remained unchanged from years 1–14, and soil pH in the limed and capped areas was initially increased but fell back to starting levels within 12 months and remained low for 14 years. In contrast, soil pH in the Terra B area resulted in soil high pH immediately after treatment and increased in years six and 14 without further treatment. Tree height and density in 2005 and again in 2013 indicated acidity in the control, limed and capped areas suppressed tree height and density; however, in the Terra B area, revegetation in 2013 was comparable to undisturbed forest. Outcomes in the control, biosolids and three Terra B areas in Program #2 were similar to those observed in Program #1.Program #3 showed the submerged and exposed tailings initially had low pH and high concentrations of total and leachable metals before treatment, but these became non-leachable after treatment with Terra B. Revegetation was achieved on the tailings beach, with almost uniform colonisation of bulrush and common reed, along with bottlebrush and golden wattle; a variety of reptiles have also been observed on the revegetated tailings beach, along with migrating ducks, spoonbills and grebes.CITATION:Fergusson, L, Blair, D and Scutts, T, ?2014. Treatment and rehabilitation of acidic waste rock and tailings – a 14-year case study, in Proceedings Life-of-Mine 2014 , pp 247–260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

Two key elements in the design of a pastefill or high density hackfill system are the preparation of the backfill material and its distribution underground. This paper examines these two areas. Owing to the essentially impervious nature of total mill tailings, preparation of pastefill and high density fill from current tailings involves a physical dewatering process. There are currently three methods available for this process: I. Vacuum or pressure filters. These represent the 'traditional' approach to the preparation of pastefill. 2. Paste production storage mechanism. This is a thickening/storage mechanism developed with the specific objective of producing paste/high density backfills. 3. Fluidization. This system utilises silos fitted with simple dewatering devices and nozzles. Recently developed by CANMET, it provides the simplest and most economical approach. This paper describes and compares the three preparation methods, from a practical and an economic point of view. Once the pastefill/high density fill has been prepared and binder added, the backfill must be distributed underground into the stopes. A fundamental factor in the design of a distribution system is the rheology of the material- No two materials will exhibit the same properties, and a sequence of rheological and related testing is required prior to the completion of the design of the underground distribution system. This paper covers the testwork normally required and discusses the fundamental design parameters of pastefill distribution systems. The final section of this paper summarises the use of pastefill at three mincsin Canada.

Jan 1, 1998

By A Parbhakar-Fox, B G. Lottermoser, N Fox

"Determining the deportment of economic and environmentally significant elements in sulfidic mine materials (eg ore, gangue and waste) requires the use of advanced microanalytical techniques, including electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Sulfidic boulders were sampled from an acid rock drainage impacted ephemeral stream adjacent to historical copper-silver workings at Baal Gammon, northern Queensland. The abundance and deportment of a range of trace elements and precious metals were analysed in these samples. Whilst many of these elements represent a potential environmental risk if leached from sulfidic rocks into streams in the surficial environment, significantly some of these elements (eg In, Sb and Co) represent specialised metals that are currently considered to be in critical supply.Sulfidic waste rock material at Baal Gammon is dominated by chalcopyrite, arsenopyrite, pyrrhotite and pyrite. Microanalytical investigations revealed that chalcopyrite contains significant quantities of In, Sn, Ag and Zn either substituted directly into the crystal lattice or occurring as discrete sphalerite and stannite inclusions. Arsenopyrite, which may comprise more than 50 per cent of some boulders, is notably enriched in Sb, Co and Ni but also contains inclusions of sphalerite, chalcopyrite and stannite. In contrast, pyrrhotite contains no trace elements of economic significance, but instead represents a likely contributor to acid generation during oxidation in the surficial environment. Trace metals (eg In, Sb, Co, Ni, Zn) are liberated during sulfide oxidation of these boulders in the surficial environment, generating a metal-rich, low-pH leachate.Fe-oxides precipitated as rinds on the surface of these boulders under low pH conditions also contain abundant As, Bi, Sn, Cu and Zn. Abandoned or historical mines represent potential sources of metalliferous drainage that poses potential environmental risks to water and habitats. However, sulfide-rich historical waste rock, stockpiles and processed waste (eg tailings) at abandoned mines may also represent significant sources of critical (eg indium) or other significant metals (eg Sn) that if liberated economically could improve environmental conditions in and around abandoned and historical mines.CITATION:Fox, N, Parbhakar-Fox, A and Lottermoser, B G, 2016. Critical and Deleterious Metal Deportment in Sulfidic Waste Rocks, Baal Gammon, North Queensland, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By D Baas, D Bennett

This paper describes how Brisbane-based PanAust Limited develops process control strategies that are implemented at all operations and are used in functional descriptions for plant upgrades and new projects.The process control strategies are determined by operating management philosophies designed to maximise returns from the company’s assets.The approach is endorsed in the project planning and design phases to ensure facilities and equipment that form the major production assets are fit for purpose and capable of enabling the production managers and operators of the projects to maximise shareholder returns.PanAust’s process control approach has been to develop sets of process control standards which focus on two key areas. The first area covers hardware requirements and architecture, software objectives, control models and individual loop tuning methods. The second area defines control room layout, graphic standards and the alarm philosophy. The application of these standards in a new plant or upgrade decreases the time required to achieve design capacity and optimal performance.The PanAust process control strategy changes the operator’s role from one that controls a number of individual loops to one that sets the control objectives of the processing plant. To achieve optimal performance, all the process areas of the plant are analysed to identify opportunities to improve throughput, recovery and stability. Once a key opportunity is identified, a process control strategy is developed which defines the objective of the control, its functionality and how an operator will interact with it. After development of the control model the operators assist engineers to test and debug it. Once the model is robust, it can then be duplicated throughout the group and developed as a group process control standard.CITATION:Baas, D, Bennett, D and Walker, P, 2014. Developing process control standards for optimal plant performance at PanAust Limited, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 325–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By J Rowland

"This paper was primarily put together in order to demonstrate what are believed to be acceptablestandards, in relation to ventilation surveys and the subsequent model assembly process. Thiswas brought about by the fact that in many parts of the world it is regarded as acceptable to carryout ventilation surveys and then build and supply the client with a æstick fi gureÆ type ventilationmodel. Such stick models have arguably litt le use and a very short life span in the real world and isalmost impossible for site staff to maintain. Thankfully most underground coal mines in Australia strive to maintain a true replica model of their ventilation circuits and to keep them in a relatively good state. Given that these mines own and maintain the models, it is often seen as necessary to update or rebuild them. The level of survey detail required to do so is totally dependent on the end use of the data and the criticality of the accuracy of the data set, to the ongoing safety and viability of the business. Mine technical personnel should think clearly about the use and importance of the ventilation survey and subsequent report outputs required that will help them bett er understand their mines and bett er prepare them to manage their ventilation circuits, on an ongoing basis. This paper provides some guidance for Australian ventilation engineers so they may plan and execute this work æin houseÆ, should they rightly choose to do so. To this end, methods of data collection and circuit analysis required for surveys of a high order of accuracy are detailed. Also, some of the issues which are important when formulating a strategy to carry out the appropriate ventilation survey for the required purpose are summarised. As well, the major details that should be furnished within any survey and some survey/report outputs and/or omissions, which are clearly not acceptable, are highlighted."

Jun 1, 2012

By R M. Yanamandra, M Kumar, S K. Tripathy, N Mangadoddy, P Sudikondala

Spiral concentrators are one of the flowing film gravity concentration devices used to beneficiate coal and mineral ores. The aim of the current study is to understand the particulate flow and separation performance of an LD9 spiral concentrator using a multi-phase Computational Fluid Dynamics (CFD) model. The CFD model utilises the Algebraic slip mixture model to simulate particulate flows. The model employs the Renormalisation group (RNG) k-ɛ turbulence models to resolve the fluid turbulence. Initially, the volume of fluid method was adopted to track the water-air interface. Simulations were then carried out at low (0.3 and 3 wt.%) and moderate (15 wt.%) solids concentrations. Multiple particle-phase representing particles of poly sizes (75–1400 µm) and multi-densities (1450–2650 kg/m3 ) were simulated to study the particle segregation on the spiral trough surface. The numerical predictions are compared with the literature performance data at a diluted pulp flow rate of 6 m3 /hr. The results were found in close agreement. Further, the same CFD model is used to study the change in pulp velocity, streamflow rates, and separation performance at increasing solids concentration. For the same density particles, Fine particles mostly show higher volume concentration in the middle and outer trough regions, whereas coarse particles show higher volume concentration in the interior and central trough regions. It implies that the fine particles mostly segregate towards the outer region, and dense particles segregate towards the axial column.

Aug 24, 2022

By J G. McLellan, B Miller

Copper and Gold mineralisation at the Ernest Henry deposit is bound by two controlling shears along the hanging wall and footwall margins. The shear zone geometries have been influenced by a large diorite intrusion, dated at ca. 1660 Ma, which lies to the north-east and south-west of the main orebody. The shear zones, which partitioned strain prior to the main mineralising event ca. 1514–1504 Ma, and in conjunction with adjacent regional structures, have been a critical factor in the deposit location and geometry. Conventional exploration techniques have been utilised proximal to the current deposit since the initial discovery in order to expand upon known resources, with limited success. However, new geomechanical modelling techniques have now been employed to target structurally controlled mineralised zones in three dimensions. The main aim of the geomechanical modelling was to simulate the effects of regional deformation events to highlight areas of anomalous strain, which indicate areas with a higher likelihood of fluid focusing and mineralisation potential. This project was focused on testing the latter stages of a D3 event (NE-SW compression) to examine preconditioning of the system, and a D4 event (SE-NW compression) which have ultimately been responsible for the current location of the mineralisation.CITATION:McLellan, J G and Miller, B, 2017. Geomechanical modelling of the Ernest Henry iron oxide copper gold deposit – identifying fluid pathways to predict potential mineralised zones, in Proceedings Tenth International Mining Geology Conference 2017, pp 75–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By R Castedo, P Segarra, I del Castillo, L M. López, J A. Sanchidrián

This work investigates some suggested methods for blast vibration monitoring on a hard surface based on 53 tests on a vibration exciter. Errors in the measurement attributable to coupling have been described as function of frequency by the rock-to-mount (or coupling) transmissibility, ie ratio of the velocity of the vibration sensor mount to the velocity of the rock motion. Transmissibility has been measured from 2 to 200 Hz, at two vibration levels (5 and 20 mm/s), in four seismographs. Attachment methods with an anchor, thermal adhesive and gypsum plaster allow stiff rock-to-mount coupling. They ensure accurate measurements (errors below 0.3 dB) for frequencies commonly found in blasting (below 100 Hz) irrespective of the mount characteristics and the vibration level. Free laid mounts and sandbagged vibration sensors lead generally to a poor, weak coupling. Errors are non-linear errors with the input velocity, ie the operating frequency window narrows as the velocity of the ground increases. Free mounts follow ground motion acceptably well (error up to 0.4 dB) at both vibration levels and frequencies below 15 Hz. At higher frequencies, free mounts lead to the largest distortions with expected errors ranging from 0.8 to 6.6 dB. Sandbagging limits the expected errors below 1.3 dB, but it does not prevent large errors that can be up to 4.5 dB. Both frequency and velocity should be considered together to assess the measurement errors instead of the expected accelerations, as it is currently made.CITATION:Segarra, P, Sanchidrián, J A, Castedo, R, López, L M and del Castillo, I, 2015. Effect of vibration sensor mounting method on the quality of vibration measurements, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 545–552 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By D MacKay

The Mt Wright Project is located near the town of Ravenswood in North Queensland and is operated by Carpentaria Gold – a wholly owned subsidiary of Resolute Mining Limited. Underground Development of the current Mt Wright orebody commenced in June 2006 and the first production ore was brought to surface in June 2007. The orebody is a rhyolite pipe containing fine-grained disseminated gold in a granite host rock. Ground conditions tend to be good to excellent throughout development, with some minor deformation experienced when stope-sized excavations are formed. The mine commenced as a sublevel open stoping (SLOS) operation with the intent to utilise development waste to back fill isolated upper level stopes while developing to the bottom of the known orebody. The mine plan intended to commence production with a bottom-up primary/secondary stoping retreat through the main orebody utilising cemented fill. Some challenges were faced during the initial production phase that included:•Ongoing underground diamond drilling and updating of the block model resulted in some issues reconciling the grade control results to the resource model. This was primarily due to the high variability of grade which in turn caused difficulties in accurately identifying areas of low and high-grade.•The cost of establishing and operating a cemented fill plant to achieve the planned extraction sequence of the orebody had increased significantly beyond initial estimations.•Geotechnical conditions such as stress orientations, ground behavior and response to the forming of excavations learned through the mining of the upper level stopes were different to the assumptions made during the initial design.A number of in-house and external reviews of the mining method were completed which has resulted in a revised mining plan. This paper will summarise the challenges faced and the implementation of the mine plan to date.

Mar 21, 2011

By B Rouvray, R Bertuzzi

The development of a design-and-construct tunnelling project in Australia from its concept to its construction requires designs to be prepared and reviewed at several distinct stages prior to documenting ‘for construction’. On recent projects the post-tender stages have been variously called 30 per cent—70 per cent—100 per cent; or concept–substantial–final; or system definition–preliminary–critical. The design is reviewed at each stage by the designer’s internal reviewer, the contractor and its independent advisor(s), the owner and its independent advisor(s), the project’s independent certifier, proof engineers and often third-party stakeholders and their advisors. Documentation for each stage often dominates the design effort, at times distracting from design. This paper presents the authors’ experience of this design-and-review process. Comparisons of design budget and actual design spend and design program implications are presented. It is postulated that a subtle change has occurred in our industry that has diminished the value of the design dollar. Is there a better process? An alternative is suggested.CITATION:Bertuzzi, R and Rouvray, B, 2014. Reducing the cost of tunnel design in Australia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 501–506 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By S J. Tear, L D. Queen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Frieda River Project is located in the north-west of Papua New Guinea. The target commodities for a bulk mining operation are copper and gold associated with a large felsic porphyry system. The project comprises a series of deposits, with the Horse-Ivaal-Trukai (HIT) being the largest. It also includes the adjacent smaller Koki and Ekwai deposits.Previous resource estimates for the HIT were made using 14 separate mineralised domains based on structure, copper grades, lithology and alteration. H&S Consultants (H&SC) has revisited the deposit and concluded that a simpler methodology could be used for resource estimation without using wireframes as hard domain boundaries. This conclusion is based on reviewing all the available geological data combined with geological and resource experience of porphyry deposits.It is generally acknowledged that porphyry deposits form by diffusion of mineralising fluids through the host lithologies, meaning that sharp boundaries are unlikely unless these fluids encounter specific physical or chemical boundaries. It is important to prepare a comprehensive geological model prior to attempting resource estimation as it forms the framework for the estimates; however, not all geological features may be relevant to the distribution of mineralisation and there can be a tendency to overcomplicate the estimation process by using too many domains. Unless a hard boundary can be identified consistently and unequivocally, it is generally better not to use a boundary in that location.H&SC completed unconstrained models with no top-cutting using both a simple flat search ellipse and a steep search ellipse to generate global resource estimates reported within a predetermined pit shell at a 0.2 per cent copper cut-off. Both outcomes are within 10 per cent for the tonnes, contained copper tonnes and gold ounces compared to the constrained resource estimate. The slight differences are most likely due to the different search strategies, but also indicate the robustness of the unconstrained modelling approach.CITATION:Queen, L D and Tear, S J, 2015. The Frieda kiss – keeping it simple , in Proceedings PACRIM 2015 Congress, pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By E de Necker, F D. I Hodg, L-M Cruywagen

The acid mine drainage (AMD) situation at three opencast collieries in the Witbank Coalfield, South Africa, was evaluated from different perspectives. Twenty-seven test pits were dug into the spoils of these collieries to characterise the in situ conditions of spoils of varying age. Detailed static testing was done on surrounding drill holes and additional samples were taken from the test pits. Selected samples were tested using different techniques, namely ABA, mineralogy and kinetic tests. Groundwater monitoring boreholes from the areas surrounding these spoils were also used for characterisation. The ABA results compared favourably with the in situ determinations; acidic test pits proved to be potentially acid-generating from ABA, even when the samples had neutral paste pH. Kinetic test results showed these samples to yield low pH leachate over the test period. In several of these results, the theoretical depletion of neutralising potential and the onset of acidity were well matched. NAG pH-values and final observed water chemistry corresponded for the cells predicted by ABA to acidify, but compared poorly in cells that did not acidify. Results from the non-acidic spoils were consistent with the in situ observations. Alternative kinetic test methodologies were also employed. Duplicate samples were tested in humidity cells and in aerated trays that were manually wetted on a regular basis. Results from these tests showed an excellent correlation. Detailed mineralogical determinations using XRD and XRF were used for comparison to the ABA and, in some cases, humidity cell results. These comparisons show that the ABA results are consistent with the results expected from the mineralogy. The conclusion from these assessments is that ABA, in most cases, provides information that can be correlated to the field, mineralogy and to humidity cells. The use of multiple techniques leads to a higher degree of confidence in the use of the data.

Jan 1, 2003

By I Sherrell, R Jain

Worldwide iron ore feed grades are trending downwards and will continue to do so with the increasing difficulties of upgrading ores. This has led to operations looking for ways to capture current tailings that still contain valuable material. In the past, these were acceptable to dispose of, but this practice is no longer economically feasible. With the increasing trend of re-mining previous tailings deposits that could be decades old, new equipment designs have been introduced to upgrade current or historic beneficiation plants. These designs can effectively upgrade these tailings to saleable products.Outotec conducted test programs for upgrading iron ore tailings from flotation rejects, thickener underflow or tailings dumps on samples provided by customers around the globe. The studies utilised Outotec’s SLon vertically pulsating high-gradient magnetic separator in combination with preprocessing equipment such as low-intensity magnetic separation, screen or scrubber and flotation for downstream processing of the magnetic concentrate. A review of the equipment required to economically process these tailings is provided, along with testing data and industrial implementation examples. The effect of different operational and design parameters on Fe grade and recovery from processing each tailings sample has been highlighted.CITATION:Jain, R and Sherrell, I, 2015. Iron ore tailings reprocessing to maximise ore production, in Proceedings Iron Ore 2015, pp 149–158 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

In the last 40 years, New Zealand has developed a number of liquid- dominated geothermal steam fields, for electricity generation and indus- trial process steam. New technologies were developed, and in this work, New Zealand led the world. The policy of full publication of the results, in a wide range of sciences, provided a reservoir of detailed data defin- ing the geology, size and shape, and the chemical and physical regime, of many geothermal fields and their constituent parts. The discovery of precious and base metal deposits /precipitates in geothermal drill cores and steamfield equipment, suggested a clear link- age with epithermal mineral fields in general, and with that of the Coromandel (Hauraki) Region in particular. Further work on geothermal/ epithermal relationships have implied that the techniques, developed to obtain an understanding of geothermal fields, could be applied also to epithermal mineral exploration. This work is developing fast, and is now proceeding in many coun- tries. Future work may show that the presumed relationship between geothermal and epithermal deposits may be applicable in the wider con- texts of all hydrothermal deposits, and possibly in many other minera- lised areas with volcanic "country rocks".

Jan 1, 1988

Using Dynamic Simulation Throughout a Process Plant's Life Cycle

Sep 13, 2010

By P de Caritat, A Davidson, A Mann

Top outlet sediments from the National Geochemical Survey of Australia have been extracted by a partial extraction method for over 50 elements including gold. The partial extraction results from this low-density survey show discrete coherent anomalies for Au in the vicinity of many of AustraliaÆs known goldfields, and in the vicinity of some minor gold occurrences. In several instances catchment outlet anomalies for Au have been recorded from areas not known to contain significant economic gold. Several large economic goldfields are shown to not produce anomalies in catchment outlet samples. A survey of overbank samples in the Swan Avon catchment of Western Australia at double the sampling density shows that low level anomalies (>1 ppb) can be traced back to source using overbank sediments. Follow-up of one of the Au anomalies at Kent River in previously regarded non-auriferous terrain (western Albany-Fraser Belt) indicates a non-economic, but perhaps geochemically significant, Au anomaly with associated pathfinders including palladium. This may indicate that further exploration of the western part of Albany Fraser Belt for Au is warranted. The combination of catchment overbank samples and partial analysis technique has been shown to be effective at locating the source of gold anomalies from initial low-density continental and regional surveys.CITATION:Mann, A, Davidson, A and de Caritat, P, 2013. High resolution soil geochemistry for gold exploration at the continental, regional and prospect scale, in Proceedings World Gold 2013 , pp 167-174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By B L. Coulter, E Wightman, A S. Burrows

With their commitment to sustainable development in an increasingly carbon-constrained world, many resources companies are focused on reducing the energy required to create their final products. In particular, the comminution and smelting of metal-bearing ores are both highly energy-intensive processes. If resource companies can optimise the energy efficiency across these two processing stages, they can directly reduce their overall energy consumption per unit mass of metal produced and thus reduce their greenhouse gas footprint. Traditional grinding and flotation models seek to improve the efficiency of mineral processing, but they do not consider the energy used by downstream metal production, eg smelting and refining. Concentrators and smelters individually may be running efficiently, but are they optimising energy consumption of the overall system? A key step towards answering this question is to understand whether it takes less energy to remove an impurity in the concentrator or the smelter. Analysis of the complete concentrator û smelter process chain may show that there are times when the concentrator should use more energy to reduce the overall energy requirements across the mill and smelter. The new methodology discussed here will integrate downstream processing energy with mineral processing energy, to find the overall most energy efficient circuit design and operating strategy. The proposed methodology includes: determining what grade and recovery positions can be achieved in the concentrator by using different combinations and amounts of grinding and regrinding, thermodynamic calculations of the energy used to process the different concentrate grades to metal, and integrating the concentrating and smelting models to find the lowest total energy for the system. A case study which investigates the effect of increasing regrinding energy on the overall mineral processing û smelting energy consumption is presented. For the copper-nickel sulfide ore investigated the addition of regrinding results in 11 per cent less energy being used in the overall concentrator û smelter process chain per tonne of metal produced. Although regrinding is often seen as an energy-intensive process, in this case study the use of 1 kWh of energy for regrinding reduces the overall energy consumption by 12 kWh. The new mill to melt methodology will allow companies to model energy consumption from mill to smelter with a view to reducing the energy-intensity and greenhouse gas footprint of their processing and smelting operations.

Jan 1, 2009