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By D R. Peacor, J L. Mauk

Dioctahedral clay minerals in the volcanic-hosted Golden Cross epithermal Au deposit, New Zealand, have been investigated by petrography, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy/analytical electron microscopy (TEM/AEM) to determine the nature of these minerals in a hydrothermal ore deposit. Heterogeneity in the distribution of dioctahedral clays is observed from the hand-specimen scale to the TEM scale, indicating that primary rock textures and fluid pathways (related to rock type, porosity/permeability and fluid/rock ratios), in addition to temperature, are important factors controlling the distribution. As the proportion of illite in mixed-layer illite/smectite (I/S) decreases, TEM observations show decreasing layer stacking order, parallelism of packets, and packet size, and increasing apparent porosity. AEM structural data show a corresponding decrease in AlIV, AlVI, and K+, and an increase in Si, Ca2+, and Fetotal. The observations of this study indicate that local dioctahedral clay mineral reaction progress is controlled mainly by permeability and structure, but that this is superimposed on a predictable, system-wide clay mineral distribution that is controlled by temperature and fluid/rock ratio.

Jan 1, 1999

The SAG milling circuit at Paddington was designed on limited bench testwork and since commissioning with the exception of some mechanical problems has performed well.

Jan 1, 1987

By F Flitti, M Haest, O Dominguez, D Mittrup, G Hird

The automated geology interpretation (AGI) tool has been developed in BHP Billiton to automate stratigraphy logging of drill holes, using any available quantitative data sets. At present, AGI is set-up to utilise geochemistry and mineralogy from infrared spectroscopic data to predict stratigraphy. Once the AGI tool is calibrated, results show that the tool is capable of automatically defining stratigraphy across all of the deposit types, encountered by BHP Billiton Iron Ore in the north-west of Western Australia. Accuracy of AGI at predicting stratigraphy is on average better than 75 per cent, with average accuracies exceeding 85 per cent for some deposit types. The AGI tool can deliver fast, accurate, consistent and objective geological interpretations.AGI is currently being implemented in BHP Billiton Iron Ore Exploration to streamline the drill hole logging process and allow geologists to spend less time defining stratigraphy at the drill hole level and more time investigating stratigraphy in 3D. This will deliver improved geology models, with significant downstream benefits in terms of better resource models, more accurate mine plans, higher plant efficiencies and more consistent ore products, driving productivity in BHP Billiton Iron Ore over the next decade.CITATION:Mittrup, D, Flitti, F, Hird, G, Haest, M and Dominguez, O, 2015. Semi-automated geological interpretation using assay and infrared spectroscopic sensing parameters towards improvements in geological modelling, in Proceedings Iron Ore 2015, pp 313–318 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By De Broglio R

The Mae Moh coal deposit was discovered some 60 years ago by villagers who noticed spontaneous combustion of coal outcrops. The first production began in the 1950's to fuel a fertilizer plant and a 12.5MW power station. During the period 1976 to 1979, three 75MW power station units were constructed on site. These have a total daily coal consumption of some 5000 tonnes and are served by a stockyard of approximately 60 000 tonnes total capacity. Stacked coal is reclaimed by means of a front end loader onto reclaim conveyors. During the years 1983 to 1986 four 150MW power station units were constructed east of the eastern seam subcrop, sons 2 km from the original power station complex. These have a daily coal consumption of nearly 12000 tonnes and are served by a stockyard of total capacity 270000 tonnes, equipped with two stackers and two bucket-wheel reclaimers for a totally mechanised system.

Jan 1, 1986

To reflect on the early history of mining in South Australia requires considerable imagination and rashness. The people who were the chief actors in the scene have long since passed away. Accounts of their activities are hazy and debatable. A broad brush account is all that I can hope to accomplish under these circumstances. It is fitting that a picture be painted and possible lessons learnt from the achievements of our pre- Decessors.

Jan 1, 1987

By D Connelly

As the resources sector becomes tougher with rising costs and cyclical metal prices, mining companies need to continue to reduce their costs and do more with less. Many new resource projects fail to come in under or on budget based on Feasibility Studies. Particularly, capital expenditure (CAPEX) proves difficult to achieve for resource projects. A number of resource projects have failed because of aggressive plant CAPEX cost cutting resulting in projects with no surge capacity and are unable to achieve design throughput. In addition, the plants are not operable because of the omissions. In recent times many businesses have also experienced the "costs" of simply implementing aggressive operating "cost cutting” measures as a strategy for solving business performance problems. This paper looks at technology driven, employment related, luxury cuts, department cuts and restructuring cuts. In the past companies used an incremental approach based on the use of past budget information as an integral part of the budget construction process going forward. The use of performance reports and Management Information Systems (MIS) is examined along with the role of continuous improvement in achieving sensible cost cutting.

Aug 8, 2011

By D Kentwell

This extended abstract and associated presentation provide a series of real examples of the complex interactions between the numerous input parameters, both geological and mathematical, that are required for resource estimation. Many of these parameters can contain a large degree of uncertainty at the initial resource stage. The resource tonnages and grades at economic cut offs of some types of deposits are relatively robust to these initial uncertainties while others exhibit significant sensitivity. In some cases, changes in parameters can result in counter-intuitive outcomes. Grades and confidence levels are inseparable; as the parameters change the confidence changes and so does the grade estimate. The extended abstract and associated presentation also discuss the question of whether or not a single solution is still an acceptable outcome for an estimate or if even a set of simulations based on a single fixed set of parameters is acceptable.CITATION: Kentwell, D, 2018. Sensitive dependence on initial conditions in resource estimation, in Proceedings Complex Orebodies Conference 2018, pp 28–30 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

Traditionally, the development of a mineral resource project goes through a fairly set pattern of decisions from what commodities to search for; where to look; how to locate; what are the reserves; how can they be exploited with optimum returns for all stakeholders; where are the markets and what will be the price received; what financing arrangments? However, due to the unique nature of most mineral resource properties, the relative significance of individual parameters on the ultimate development decision will vary from project to project. Sensitivity analysis in its formal sense is most frequently related to the economic analysis of a project particularly in conjunction with the ultimate development decision making process, and acknowledges the uncertainty of the actual values with their impact on the corporate decision making yardsticks. In many cases, this analysis merely adds more values to confuse the decision makers who may well opt for some subjective rationale to overcome the numeric confusion. However, sensitivity analysis should be used more frequently to exploit the development dollar to its maximum, THROUGHOUT the phases leading to the development decision. It is essential to identify the critical inputs to the various decision tiers in a project as early as possible and direct the funds to ensure that these parameters are determined as accurately as possible. Examples are used to illustrate the need for an even-handed quantification of the parameters which affect the outcome of decisions en route to the final one while minimising the risk in making an optimum assessment in relation to development funds Available.

Jan 1, 1983

By N McIntyre, J Smart, J Ossa-Moreno, D Rivera

Hydro-economics is a field of research that analyses water resources from a multi-disciplinary approach (Harou et al., 2009). These models generally include one component that describes the water resources of the catchment being analysed (e.g. the physical behaviour of water), an economic component that describes users’ water demand function (changes of willingness to pay relative to availability) and a coupling methodology. These models go beyond calculating cash flows for water investments and analyse the economic behaviour of users when facing water shortages or surplus. In other words, water demand curves are defined for each water user (e.g. urban, agriculture, mining, environmental and hydropower), and they are used to retrofit the water resources component. As a result, the model approximates the catchment scale response to droughts and wet periods, including the effects of water markets, restrictions, recycling, water sharing and any cooperative efforts by users to adjust to changing climate conditions.These models are usually focused on agriculture and urban users, the main water consumers in most catchments, but they have sometimes included environmental, industrial and hydropower users (Bekchanov, Sood, & Jeuland, 2015). Nevertheless, although a relevant user of water in several catchments, the mining industry has been rarely included. This paper is part of an ongoing project that addresses this gap by developing a hydro-economic model in the upper section of the Aconcagua River in Chile. The aim of the paper is to analyse the sensitivity of the outputs of the model to changes in input data, both hydrological and economic, and to develop insight on usefulness of such models for reducing water conflicts in mining regions.CITATION:Ossa-Moreno, J, McIntyre, N, Smart, J and Rivera, D, 2018. Sensitivity of a hydro-economic model in a mining region to changes in hydrological and economic inputs, in Proceedings Life-of-Mine 2018, pp 52–55 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Jefferson CB

Adaptive optimisation is the adjustment of operating conditions to maintain optimum process performance as the feed quality varies. This strategy has the potential to be economic- ally better than the maintenance of a constant optimum performance with a blended feed. Application of the strategy is hindered by practical difficulties and economic risks. A computer simulation of leaching processes has been used to identify ore-process systems which have the greatest potential benefits from adaptive optimisation. They are systems with low value feed materials and a broad distribution of reactivities, in pro- cesses which are sensitive to the operating variable that is being manipulated (e.g. residence time). Improvements of up to 13% in throughput and 5% in the economic operating margin can be achieved. The results are sen- sitive to the precise model which is used for the process kinetics. It seems that the kinetics of the last few per cent to react are particularly relevant. A realistic situation has been identified where a synergistic inter- action occurs in blended feeds which makes adaptive optimisation disadvantageous.

Jan 1, 1984

By Kolarczyk M

When controlling the ventilation process in a deep mine some knowledge of the sensitivity of the air volume output to changes in the resistances of network side branches is of great advantage.Sensitivity is taken to mean the limit of the differential quotient AV /ART where AV. is the change in air output in the i--h side branch caused by a change of resistance LI R in the r-th side branch. A method Is presen- ted for determining any arbitrary co- lumn of the sensitivity matrix. A network interpretation of this met- hod was developed in which an ancilla- ry network additional the basic network is constructed and solved, giving an analysis of the sensitivity signs de- pending on the structure of the network.

Jan 1, 1988

By A Jyoti, J R. Black, R R. Haese, E O. Ansah

Copper (Cu) is a critical metal in the transition to a low-carbon power supply. Presently, low-grade copper sulfide ores account for almost 80 per cent of the global reserves. Large amounts of water are required to process these low-grade copper ores. The mining industry utilises lixiviants from recycled water from different sources to conserve water, whilst enhancing Cu recovery. Some utilise intermediate to pregnant leach solutions, sea water, and processed water from electrowinning circuits with highly variable concentrations of ions. Previous studies have highlighted the formation of precipitates that passivate the surfaces of minerals in these low-grade copper ores and/or block flow paths for lixiviant during heap leaching. In this study, we utilised concepts of phase replacement to devise an innovative means of controlling precipitation and increasing copper recovery using industrial brine as opposed to freshwater. We propose the formation of Al-rich phases (such as AlSO4 + or alunite) to replace iron sulfate and iron hydroxysulfates (such as jarosite) during the chalcopyrite dissolution-precipitation mechanism. The rationale is to have available Fe3+ throughout the chalcopyrite leaching process. We tested this method by carrying out various batch experiments using CaCl2, AlCl3, and NaCl industrial brine types compared to freshwater and explored the capacity to leach Cu from chalcopyrite. There is higher Cu recovery during oxidative leaching of chalcopyrite in industrial brine with 91 per cent recovery using AlCl3-rich brine, 84 per cent with NaCl-rich brine, and 56 per cent with CaCl2-rich brine as compared to 35 per cent recovery using freshwater. In the absence of Al3+, various forms of iron sulfates, and jarosite are formed, reducing the availability of Fe3+ for chalcopyrite dissolution. The introduction of Al3+ leads to the formation of AlSO4 + species, thus lowering sulfate activity and the tendency for K-jarosite formation.

Aug 24, 2022

By B Nielsen, H Lehto, J Rohleder, C Robben

Sensor-based ore sorting is being increasingly used to reduce the amount of low-grade and waste material processed in mineral concentrators. This type of preconcentration provides bottom-line benefits to users by reducing the amount of energy, water and consumables, as well as reducing capital cost. Existing operations can increase metal production, while previously uneconomic deposits and low-grade stockpiles can also be exploited. The technology can also be used to separate ore types for selective processing. The path to implementing sensor-based sorting may include:• geometallurgical evaluation• first inspection testing to investigate sensor response• bench-scale testing where sensor selection is not obvious or for difficult applications• performance testing in full scale sensor-based sorting machines• larger scale site-based piloting with a temporary semi-mobile plant installation. Sorting requires material to be suitably prepared and presented to the machines and typically this consists of crushing and screening to limit top size and optimise liberation. However, where material streams are suitably sized and prepared, additional equipment may not be required (e.g. the sorting of semi-autogenous grinding (SAG) Mill pebble streams).This paper presents a case study of economic upgrading of gold ore, by preconcentrating with sensor-based ore sorting. The case study examines sorting amenability, test work, the feasibility study through to implementation, with associated flow sheet development. The development process is analysed and evaluated with a view to rationalising the process for development of future projects. In addition, limited financial modelling based on expected results is shown to illustrate the benefit to the operation.CITATION:Nielsen, B, Rohleder, J, Lehto, H and Robben, C, 2017. Sensor-based ore sorting to maximise profit in a gold operation, in Proceedings MetPlant 2017, pp 131–146 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By P Esteves, J L. Bechir, R Galery, C Senna, V Souto

The current moment experienced by the mineral industry is marked by a series of economic, social and environmental challenges. Among the main challenges, it is important to highlight the decreasing in ore grades with the gradual depletion of the existing deposits, the high volatility in international commodity prices and the operational inefficiencies in the mine, beneficiation, and metallurgical plants. In this context, mining companies are continuously looking for alternatives that minimize production costs and maximize overall production. In addition, recent tragedies involving tailings dam collapses in Brazil, reinforced the need for a more responsible, sustainable, and conscious mining, such as aiming the preservation and rehabilitation of the land environment. In this scenario, the Sensor-Based Sorting (SBS) technology is currently getting more space into the mining market. This separation technology aims the removal of gangue material in coarse particle size fractions, prior to comminution and concentration stages. As a consequence, the technology allows a smaller consumption of energy, water, chemical reagents and other inputs. Moreover, the sensor-based sorting is a dry processing technology and favors the reduction of fine material to be sent to the tailings. The aim of this paper is to provide information regarding the technical and economical evaluation of SBS technology applicability to a zinc silicate mining in Brazil. The project evaluation was performed in two stages: laboratory test work and the execution of a pilot plant. The execution of a pilot plant allowed the technology optimization, quantification of downstream process effects, such as a proper economic evaluation about the technology benefits. Keywords: Sensor-Based Sorting; Particle Sorting; Ore Sorting; Preconcentration; capital expenditure (CAPEX); operating expenditure (OPEX); zinc; comminution; dry processing.

Nov 10, 2020

By M W. N Buxton, M S. Shishvan, J Benndorf

The flow of information, and consequently the decision-making along the chain of mining from exploration to beneficiation, typically occurs in a discontinuous fashion over long timespans. In addition, due to the uncertain nature of the knowledge about deposits and the inherent spatial distribution of material characteristics, actual production performance in terms of produced ore grades and quantity and extraction process efficiency often deviate from expectations. Reconciliation exercises to adjust mineral reserve models and planning assumptions are performed with timely lags of weeks, months or even years.With the development of modern information and communication technology over the last decade, a flood of data about different aspects of the production process is available in a real-time manner. For example, sensor technology enables online characterisation of geochemical, mineralogical and physical material characteristics on conveyor belts or at working faces. The ability to utilise this additional information and feed it back into reserve block models and planning assumptions opens up new opportunities to continuously control the decisions made in production planning to increase resource recovery and process efficiency. This leads to a change in paradigm from a discontinuous method to near real-time reserve reconciliation and model updating, which calls for suitable modelling and optimisation methodologies to quantify prior knowledge in the reserve model, process and integrate information from different sensor sources, back propagate the gain in information into reserve models and efficiently optimise operational decisions in real-time.This paper introduces the concept of an integrated closed-loop framework for real-time reserve management, incorporating sensor-based material characterisation, geostatistical modelling under uncertainty, modern data assimilation methods for sequential model updating and mining system simulation and optimisation. The effectiveness of the framework and the value added will be demonstrated in an illustrative case study.CITATION:Benndorf, J, Buxton, M W N and Shishvan, M S, 2014. Sensor-based real-time resource model reconciliation for improved mine production control – a conceptual framework, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 223–234 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By S Gray

Based on the 2021 Volume 5 State of PlayTM mining survey of key executives and board members in the mining sector, the key responses to ‘Which of the following technologies will have the biggest impact on mining in the next 15 years?’, were ‘Sensing and Data’ followed by ‘AI and Analytics’. From the early 1970s it would have been unlikely to predict the level of sensing and automation introduced to the broad industrial sector. No better example is the automobile industry where the combination of technological advances and external drivers (such as emissions control) have driven an incredible rate of change. The introduction of sensing, data, AI, and automation in the mining industry is just ramping up. Until now our energy efficiency, environmental footprint, labour shortage, skills, and safety have not been challenged by stakeholders in the way we are seeing market forces develop today. In order to address these challenges, we need to look back to the automobile industry and learn their lessons to accelerate our application of digital capability, analysis, AI and automation This is critical, particularly as access to skilled human resources becomes more difficult. An example of how this can be achieved in a gold processing plant utilising the latest real-time sensing technologies is the ‘Carbon Scout’ developed by Curtin University, and OLGA developed by CSIRO, which are both online technologies, coupled together with Gekko’s ‘Neon’ digital platform to achieve a fully automated real-time gold processing system.

Aug 24, 2022

By W Ward, J Clegg, R Barnes, T Zhong

This paper provides an overview of methods for measuring tunnel deflection and construction’s effects on the surrounding environment during and post construction. It will also review illustrative case studies from within Australia and overseas that are most relevant to local construction conditions. Systems illustrated include; vibrating wire and fibre optic strain gauges, extensometers, load cells and piezometers. A novel system using radar interferometry which requires no contact to the structure will also be investigated.In Australia, the majority of tunnelling activity occurs in urban areas (or in the case of mining in rural area) with limited seismic risk. However, the unexpected movement of tunnels is an important factor for structural engineers to monitor. During construction, monitoring is focused on the performance of the tunnelling lining, the supports under real conditions and the effects on surrounding infrastructure. After construction, monitoring will determine the effect of live traffic loads and can also evaluate the durability and any degradation of the tunnel. The aging of some tunnels or the forces subjected by nearby major construction can directly lead to a decrease in structural stability and deformation.The conventional way of inspecting and monitoring those tunnel movements is to have engineers physically enter the tunnel and carry out the measurement work. Manual techniques include tunnel wall convergence checks or total station measurement. However the associated costs are high and measurement process is difficult as some tunnel areas are inaccessible and the data collection interval is limited by the speed of the operator.Automated sensor networks utilising extensometers, fibre optics sensors or strain gauges can be used on tunnel segments or surrounding buildings. Ground settlement measurement via boreholes or hydraulic monitoring points and remote measurement of dynamic deflection can be taken using microwave interferometry.CITATION:Ward, W, Barnes, R, Zhong, T and Clegg, J, 2014. Sensors and systems for the measurement of tunnel movements during and after construction, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 209–218 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

Results of blasting trials conducted at Gregory Mine, a large open cut coal mine situated in the Bowen Basin, show that fragmentation was improved or equalled whilst reducing the amount of explosives previously required. This was achieved by a system of deck loading whereby two or more explosive charges, separated by air gaps, were positioned in the blast hole, thereby extending the effective explosive column whilst minimizing the total explosives required. In the three trials to date, a saving of approximately 213 kg of ANFO per blast hole was achieved. This represented an approximate 20% reduc- tion in ANFO requirements.

Jan 1, 1989

By Lin C, Jiaxiang D

A series of experiments were carried out with Hallimond tube in order to test the effects of different reagents. A good result has been obtained when potassium-n-butyl xanthate is used as collector for molybdenite and graphite complex are depressed by the depressor mixed with nigrosine and iron (III) chloride. The separating mechanism has been studied with help of many modem instruments.

Jan 1, 1993

Separating Particles by Horizontal Deflection in a Paramagnetic Fluid This paper describes the horizontal deflection behavior of particles in paramagnetic fluids under a high-gradient superconducting magnetic field. Movements of single particle were observed experimentally and indicated that they could be deflected to different positions. Based on these results, the behavior of groups of particles from ore samples was examined in the superconducting magnetic. It was found that these particles could be deflected and settled at a certain position due to the combination of gravity and magneto-Archimedes forces as well as a lateral buoyancy (displacement) force. Mineral particles with different susceptibilities and/or densities could be deflected to different positions, thus producing groupings of similar types of particles. The work described here, although in its infancy, could form the basis of new approach to separating particles based on a combination of susceptibility and density.  

Sep 13, 2010