Search Documents

The history and milestones in the evolution of support systems utilised in the mass-mined chrysotile mines of Shabanie and King are discussed in detail. The use of block caving, false footwall or sublevel caving mining methods brings with it some major support problems, which are exacerbated, in our low rock strength mining environments. The paper discusses the various support elements and systems that have been used successfully or otherwise in these operations. Some predictions for the future of rock reinforcing in our ground conditions are highlighted, in relation to geomechanics, levels of mechanisation and production risk analysis.

Jan 1, 2000

By Y Peng, B Guo

In gold processing plants, the water from the cyanidation stages is treated to detoxify cyanide species and this recycle water becomes the main part of the process water. Despite the low concentration of free and weak acid dissociable (WAD) cyanides in process water, the recoveries of gold and silver is still affected during flotation, especially when gold and silver are associated with iron sulfide minerals. This is a case at the Hidden Valley (HV) Mine. In this study, the effect of free and WAD cyanides on gold and silver recoveries by flotation from the HV Mine was considered.WAD cyanide (WAD CN) was prepared by mixing sodium cyanide and copper sulfate at a cyanide to copper ratio of 3:1 dosed at different cyanide concentrations. It was found that both free and WAD CN depressed gold and silver and particularly iron sulfides in flotation. The depressed gold and silver recoveries were closely associated with the depressed recovery of iron sulfide minerals, suggesting that free and WAD CN may not depress the flotation of liberated gold and silver minerals significantly. It was also found that 10 ppm free cyanide completely depressed the flotation of iron sulfide minerals and WAD CN depression is probably through the WAD dissociation to free cyanide species (mainly aqueous HCN) during the grinding process, resulting from a decrease in pH. Thermodynamic calculation showed that 5.5 ppm free cyanide was released in the end of grinding at an initial WAD CN concentration of 50 ppm. This research provides a guideline to counteract the negative effect of WAD CN in the flotation of gold and silver minerals.CITATION:Guo, B, Peng, Y and Espinosa-Gomez, R, 2013. The effect of weak acid dissociable cyanide on gold and silver flotation in Hidden Valley Mine, in Proceedings World Gold 2013 , pp 341-346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By R Forster

Direct ship iron ore (DSO) operations at Extension Hill in Western Australia’s Midwest region have commenced, with fi rst product railed to the port of Geraldton in July 2011. Reserves are 14.8 million tonnes (Mt) of haematite-goethite ore overlying an Archaean BIF-hosted larger magnetite deposit which Mount Gibson Iron Limited (MGI) sold to other parties in 2006.Some unique geological aspects of the deposit shape DSO mining and processing operations. Owner-operator selective mining, blending, crushing and screening on site will produce three million tonnes per year (Mt/a) of Lump and Fines product to be trucked 86 km to Perenjori, railed 232 km to Geraldton, and loaded aboard Panamax-sized ships through the dedicated iron ore shiploader at the Geraldton Port Authority’s Berth 5 facility.The statutory approvals process for this project formally began in 2004, dominating delays in a predevelopment phase which extended over a longer period than the likely life of DSO operations. The lack of transparency, uncertainties and costs inherent in state government processes have influenced decisions made by MGI while assessing other development opportunities in Western Australia. Potential for additional Reserves exists at Extension Hill, however MGI’s ability to extend the mine life will hinge on statutory approval to explore for and evaluate other DSO resources on surrounding granted mining leases.The nature of the resource and use of existing infrastructure for product transport have enabled MGI to keep operating costs and capital intensity of this project relatively low. A tenacious development approach by MGI and robust project economics have fi nally enabled this site to take its place as a revenue earner beside the company’s other DSO operations at Tallering Peak and Koolan Island.

Jul 11, 2011

By R Yong, A McEwan, D G. Miljak, D Milinkovic, A Curtain, P J. Coghill, R Stefulj, B Lovric, G Roberts

The CSIRO has pioneered the development and use of certain classes of magnetic resonance (MR) for mining applications. The MR technique is a radio frequency-based spectroscopy that provides highly quantitative measurement of selected ore minerals. MR has many inherent advantages for bulk sensing in mining applications, including deep sensing penetration into most bulk ores with the use of non-contact sensors that are robust and tolerant of demanding mine conditions. The highly discriminating nature of the technique also provides the very desirable attribute of robust and simple calibration, that can often be performed prior to sensor installation. Rapid sensing (within seconds) at very low grade (few hundred ppm Cu) has been demonstrated, as well as sensing at high tonnage rate. Besides sorting applications, MR may also be applied to preconcentration applications involving very large volume sensing including: (i) haul truck sensing using portal arrangements, where truck destination assignment may be dynamically determined based on the truck grade, (ii) in-pit gantries used for loading trucks that may similarly be equipped with sensors for truck assignment and (iii) deep mine bench sensing, recently progressed through a CRC ORE project, where local bench grade is determined at the few-metre lateral scale and at depth prior to blasting, to aid selective blasting and ore extraction. MR sensor prototypes have been developed for each of these applications and have been tested in laboratory or limited field conditions. To inform the value proposition for truck or bench sensing, initial analysis of truck assignment improvement based on an analysis of in-situ mine bench grade has been performed for a porphyry style deposit. The prototype sensors, preliminary results and future technology development and objectives will be described.

Nov 10, 2020

By P Thompson, B W. Atkinson

Water treatment is not æcore businessÆ for mining companies.Just as mineral ores and coals are unique, each requiring detailed characterisation and pilot-testing to determine their optimum beneficiation route, so too are mine waters, each requiring careful assessment to determine the most appropriate treatment. There are many cases of æregret capitalÆ expenditure, whereby mines have installed off-the-shelf equipment only to find it inadequate for their purposes or grossly expensive and labour intensive to operate.Water may be required for potable purposes, ore processing, dust control and/or irrigation. A major driver will frequently be environmental constraints for off-site discharge. Mine water projects can become very complex, and detailed models need to be prepared and optimised to properly consider the raw water sources, the on-site storages, the on-site uses and the off-site discharges, as well as handling the residuals (by-products) of water treatment. By-products may be in the form of concentrated backwash streams or streams of elevated salt content. Careful management of the by-products is required to avoid recontamination of the source water.Regulators often drive mine owners toward reverse osmosis (RO) so that their discharges can be considered as æzero dischargeÆ in terms of potential pollutants. Such decisions need to be based on site-specific information rather than any form of æblanketÆ requirement. An analogy is that many humans like to consume mineral water rather than ænormalÆ tap water. Receiving environments also accommodate or even prefer their æmineralsÆ and so RO is neither warranted nor sustainable in many cases.This paper presents two case studies for operating mine sites, both of which have a significant excess of water requiring environmental discharge. The examples demonstrate a sensible balance between treatment type, environmental constraints, process implementation and residuals management. LIMN« æthe flow sheet processorÆ was used to model one of the case studies due to the complexity of the water system on that site.CITATION:Atkinson, B W and Thompson, P, 2013. Mine water - optimising for site and environment, in Proceedings Water in Mining 2013 , pp 9-14 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By S Lakemond, L I. Ku, J Vaughan

Conventional processing of poly-metallic gold containing flotation concentrates are challenging for a number of reasons. One reason is that substantial copper and zinc in the cyanide leach solution compete with gold and silver for carbon adsorption sites. In this study, metal-cyanide adsorption kinetics and equilibrium are measured on three samples of coconut derived activated carbon and one sample of synthetic carbon. Loading selectivity was confirmed to be in the order gold>silver>copper>zinc for all carbon samples. The synthetic carbon tested showed promising results in terms of loading kinetics and capacity for precious metals.CITATION:Lakemond, S, Ku, L I and Vaughan, J, 2013. Effect of carbon type on adsorption of Cu, Zn, Ag and Au from mixed cyanide solution, in Proceedings World Gold 2013 , pp 411-418 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By J Herd, J Rowe, M Cutbush, d F. Aziz

WearApp provides expertise for assessing the degradation of removable screening media panels on vibrating screens right in a user’s pocket. Through the WearApp application, users can simply take a picture of a panel using their mobile, enter some basic information and have the application assess the wear to provide a recommendation for whether the panel needs to be replaced. Where traditional mechanisms for assessing panel wear only measure a few points across the panel face and rely on having personnel with specialised knowledge available to perform the assessment, WearApp uses deep learning models to analyse the entire panel face and support the user to make an informed decision. The application works through analysing a panel image and using a model to automatically detect the corners of the panel. Given the known dimensions of the panel, this enables the application to calibrate the pixel size against a known reference. A second set of models then detect the apertures and measure their dimensions. With the aperture dimensions defined the application assesses the wear of the panel through referencing a stored 3D model of the aperture. Finally, the data from each aperture is collated and the wear of the entire panel face defined. Since WearApp performs measurement of the entire panel face, it also allows the user to perform a more detailed analysis of the panel’s wear profile. Where typically, the panel wear is only measured in a few locations, WearApp’s analysis enables users to visualise the panel wear across the entire panel face, identifying areas of high wear that could be leading to premature panel replacement. Additionally, because the entire panel face is measured the change in screening efficiency can be calculated accurately for the worn panel, even taking into account the impact of aperture pegging by small rocks.

Sep 1, 2024

By R Barritt, P Scott, K Albano

Successful closure of tailings storage facilities (TSFs) is an environmental issue faced globally by metalliferous mines. During the initial feasibility and design phase of the mine life importance is placed on the physical stability of above ground TSFs, largely driven by legislative requirements, whilst closure planning is often a secondary consideration. However, as the landform is further developed and constructed attention must be paid to regularly revisit the original closure plan and update it to achieve the best (sustainable) possible outcome for both the environment and stakeholders. A mine in northern Queensland is in the process of developing a closure strategy at their TSF. Appropriate closure measures for the TSF are required to mitigate the impact of any seepage emanating from the TSF on the groundwater and surface water receptors. O’Kane Consultants Pty Ltd (OKC) have provided the mine assistance with the development of a TSF cover system design in order to appropriately manage tailings during operations and to prepare for the facilities’ closure. OKC has collected data since 2007 from cover system field trials located on the TSF. To enhance engineering judgement in the design of future cover systems, calibration of soil-plant-atmosphere numerical models to field data (referred as ‘field response modelling’) were completed. Calibrated model inputs can be used to provide insight into long-term cover system performance as well as a tool for design of the final landform.Following a site investigation, materials characterisation and numerical modelling program various cover system alternatives were developed. Two of the preferred cover system alternatives referred to as Test Plot #1 (TP#1) and Test Plot #2 (TP#2) (Figure 1), were constructed at the site and instrumented. Monitoring instrumentation comprised several nests of in situ volumetric water content and thermal conductivity sensors to measure changes in water content, temperature and matric suction within the cover system materials and underlying tailings waste. Run-off collection buckets and a fully-automated meteorological station were also installed. CITATION:Barritt, R, Albano, K and Scott, P, 2016. Findings and conclusions following ‘long-term’ cover system monitoring – refinement of the conceptual design for tailings storage facility closure, in Proceedings Life-of-Mine 2016 Conference , pp 85–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By C T. Senra, A Souza

Increasing fuel prices, unavailabilty and high prices of tyres have imposed tremendous challenges for large open pit operations. Carajßs open pit mines, one of the largest iron ore projects in the world, has been particularly affected due to the high amount of giant trucks operating in this site. On the other hand, environmental constraints push the mining industry towards reductions in fossil fuels, noise and waste generation. As a feasible response to these requirements, an alternative mining method for open pit mining, aiming to reduce or even eliminate the need for trucks has been developed, based primarily on coal opencast continuous operations. This innovative approach for open pits involves the replacement of trucks by fully-mobile crushers, bench conveyors and ramp conveyors. Two different applications have been developed for exploiting waste and ore at Carajßs largest pit, named N4E. To make it possible, mine planning paradigms should be replaced leading to new conceptual design of open pits. This paper shows two case studies (waste and ore conceptual design) carried out at Carajßs mines to anticipate and put forward the future of open pit mining, proving that our industry would be greatly affected by this new way of exploitation, reducing thousands of tons of fossil fuels. Productivities can be enhanced and environmental performance greatly improved. In this approach mine automation can be easily implemented reducing operating costs and man's fatigue.

Jan 1, 2009

By T Sparks

The Collie River catchment, located approximately 200 km south of Perth, covers an area of around 2830 km2 and is the source of run-off to the Wellington Dam, an important irrigation water resource for the Collie Irrigation District. The salinity of the Wellington Dam has increased due to historical clearing and irrigators currently use water with salinity levels approximately twice that of the Murray River in South Australia (Water and Rivers Commission, 2001). The Collie River Salinity Situation Statement (2001), released by the Water and Rivers Commission (now the Department of Water), identified realistic actions that could achieve the salinity reduction target. Subsequent benefit-cost analyses and prefeasibility studies recommended the diversion of the most saline flows in the Collie River away from the dam as an immediate intervention (URS, 2003). The East Branch of the Collie River above the locality of Buckingham (20 km east of Collie) contributes around half of the salt that flows into the Wellington Dam and the diversion and storage of the saltiest flows from the East Branch at Buckingham was identified as a viable option for reducing salinity in Wellington Dam. The proposal had one problem û the water could not be disposed of as quickly as it was diverted. However, in the vicinity of the diversion site were a number of coal mine voids and after preliminary discussions, the Government/Griffin Coal alliance was formed and from this the opportunities have continued. Diverted water would be stored temporarily in an adjacent mine void (Chicken Creek 4 void) and then disposed of to the sea. The disposal options included Western Power CorporationÆs saline discharge pipeline from Collie Power Station, or a new pipeline. The diverted water was also identified as a potential raw source for treatment and use in industry. This has opened up opportunities including desalination, water efficiencies in the power stations, increased reliability of water supply for the power stations, water for new industries, wastewater disposal options and extra water for PerthÆs water supply. In the process of solving the water storage problems the project introduced a range of mine water quality problems û heavy metals and pH û and the Department of Water (DoW) is now working with the mining industry and the Centre for Sustainable Mine Lakes (CSML) to develop treatment and management technologies. The project has received support and funding through the National Action Plan for Salinity and Water Quality (NAP) and it has been possible to accelerate and enhance this project as a result of NAP. The DoW has developed the proposal to an advanced stage and gained approvals for the capital diversion program to go ahead. The partnerships have expanded to include the second mining company, Premier Coal, the Water Corporation, Western Power and the Harvey Irrigation Cooperative. The proposal could feasibly result in a $90 million integrated water management initiative for Collie using the latest technology, mining operations and providing water for value adding industries in the local area. The DoW is not a mining company; however, our experience in managing water in times of shortage, environmental water quality criteria, competition for water and managing community expectations will have the same success factors:consultation and knowing your community and stakeholders, sharing issues and working in partnership can provide results far greater than the initial issue, even brackish water has value, every sector is in competition with each other and has to have a share of the water, an integrated approach can provide opportunities for development in areas of water shortage, and never think of water as wastewater.

Jan 1, 2006

By J T. Carswell, K Sutton

Quality control (QC) of reverse circulation drill sampling commonly involves regular duplicate subsampling to monitor the extent of imprecision or random error in the subsampling system. In gold mining in Australia, the subsampling tool is usually a cone splitter.Other sources of error, including delimitation error and bias (systematic error) in the subsampler are often assumed to be negligible or ignored for being too difficult to QC.This paper describes actual sampling errors and error mitigation based on quality assurance and quality control (QA/QC) of surface and underground reverse circulation drill sampling at a high-nugget gold mine at Sunrise Dam, Western Australia.CITATION:Carswell, J T and Sutton, K, 2014. Sources of sampling error and implications for quality assurance and quality control in surface and underground reverse circulation drilling, in Proceedings Sampling 2014 , pp 65–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By E Jak, G Khartcyzov, M Shevchenko

The increasing complexity of ore resources and recycled materials in the feed of pyrometallurgical processes present a technical challenge to the metallurgical engineers working on maximising the recovery of the valuable elements and minimising the environmental impact of the processes. To address this challenge, the availability of computational tools that can predict the mass and energy balance in complex systems is required. Then the accurate description of phase equilibria in the complex multicomponent systems describing the chemistry of the pyrometallurgical processes becomes critical for the correct implementation of the indicated tools and facing the outlined industrial challenges. In the present study the distribution of selected elements (Pb, Zn, Fe, As, Sn, Sb, Bi and Ni) between oxide liquid and metal in the ‘CuO0.5’-CaO-AlO1.5 system in equilibrium with Cu metal at 1400°C (liquidus of CaAl2O4) was experimentally studied using the equilibration and quenching technique followed by the electron probe X-ray microanalysis of the resulted samples. The study covered a wide range of effective p(O2) over the system from 10-11 to 10-3.5 (corresponding to formation of immiscible CuO0.5-rich slag). To avoid loss of volatile elements (Pb, Zn, As, Sn, Sb and Bi), a correlation between ‘CuO0.5’ in oxide liquid and p(O2) in open system was obtained first, followed by studying the volatile elements distribution in closed conditions (Al2O3 crucible sealed in SiO2 ampoule), where ‘CuO0.5’ concentration was used as a marker to evaluate the effective p(O2) over the system. The experimental results were then used for the optimisation of the thermodynamic model parameters of the system as part of the integrated experimental and self-consisting thermodynamic modelling research program of phase equilibria in the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co and Na) gas/oxide liquid/matte/speiss/metal/solids system.

Jun 19, 2024

By J E. Wajon

This paper discusses the background, requirements, need and content of plans for management of drinking water self-supplied to mining-related operations, including construction camps, especially in remote areas of Western Australia. The paper discusses the importance of cooperation between regulators, the mine site operator and the consultant in preparing a plan fully compliant with the Australian Drinking Water Guidelines to protect the quality and safety of drinking water supplied to mine sites. The paper outlines some of the issues that need to be addressed in preparing a drinking water quality management plan, such as hazard identification, risk assessment, the multiple-barrier approach and the concept of critical control points. Data requirements, monitoring, incident management, training and reporting are also covered.CITATION:Wajon, J E, 2013. Drinking water quality management for mining operations in Western Australia, in Proceedings Water in Mining 2013 , pp 321-328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By P B. Hills

Increasingly over the past couple of decades, the importance of understanding the in situ stress regime in underground hard rock mines has become accepted by all. Providers have responded to this requirement and various techniques for undertaking the measurements have been honed while others have slipped from use. It is a simple, though not inexpensive task to engage a provider to undertake the require measurements, and a comprehensive report will ensue. So, what has actually been obtained? What should the geotechnical engineer do next? What tools are necessary to do so? Regardless of the method of measurement, the report will describe the location of the measurement site and describe the basis of the methodology used in undertaking the measurements and a log of the measurement program. Finally, it will include the results, which should incorporate the normal and shear stress components of the full stress tensor. Ground control management plans (GCMP’s) and stress summary reports and spreadsheets prepared by site geotechnical engineers always include the magnitude, trend and plunge of the principal stresses. Remarkably few site-based summaries include the full stress tensor. This is a significant gap as the full stress tensor is vital for any further data manipulation. However, without the algebraic tools to undertake those manipulations, their value is diminished. This paper seeks to provide a checklist of ideas to be considered. It provides commentary on the options available to dissect the stress measurement report and ensure that the maximum possible value is derived from it. The manipulation and presentation of component stress data is also discussed. The various methods of stress measurement are not the focus of the paper but some of the strengths and weaknesses of them over which the site geotechnical engineer has some control, are highlighted.

Nov 29, 2022

By Cooper W. C, Stokes M. A

Proterozoic gold deposits in the Pine Creek Geosyncline are at present receiving renewed attention with the opening of old mines and several new discoveries. This important polymetallic province contains occurrences of gold, base metals, tin, tungsten, tantalum, platinum, palladium and aluminium. These resources have been exploited over the past century with periods of major interest during the turn of the century and during the past 20 years. Economically viable resources of predominantly gold, eg Pine Creek, Woolwonga, Brocks Creek and Union Reefs, and Ag-Pb-Zn, eg Woodcutters are currently in development or being mined. A variety of genetic models, ranging from magmatic through hydrothermal to syngenetic, have been postulated in the past for the formation of gold deposits in the Pine Creek Geosyncline. The first discussion on the regional geological factors that control ore deposition in the Brocks Creek-Howley District was by Sullivan and Iten (1952). They recognised that the most important ore deposits are associated with anticlinal and domal structures and that granites may be a controlling factor in the localisation of the mineralisation. More recently a group of authors, Needham and Roarty (1980), Goulevitch (1980), Nicholson and Eupene (1984), Sanger-Von Oepen, Friedrich and Kater, (1988), Nicholson and Eupene (1990) and Kruse, Whitehead and Mulder (1990) have suggested an exhalitive syngenetic origin, or remobilised syngenetic during dolerite intrusion and/or regional deformation, for gold mineralisation, especially those associated with South Alligator Group lithologies (eg Bridge Creek, Mt Bonnie group of mines and Cosmopolitan Howley). Studies carried out at the Bridge Creek and Western Arm Prospects over the last three years suggest that syngenetic models for gold mineralisation are less relevant to gold mineralisation in the Howley District than first thought (Wall, 1989; Partington, 1990). The Bridge Creek prospect has been cited as an example of a syngenetic-syngenetic remobilised deposit (Oepen, Friedrich and Kater, 1988) while the Western Arm prospect is more clearly a vein hosted epigenetic deposit and a comparison of the styles of mineralisation at both prospects will be made. The nature of the gold mineralisation at both prospects will be described and compared, and possible genetic models for gold mineralisation and their relevance to regional exploration discussed.

Jan 1, 1994

In practice a sampling solution is a compromise of many requirements: the sample should be representative; the sampling system should also be reliable, less than 95 per cent availability restricts the use of the assayed sample for process control purposes; no sample is the worst sample, and investment costs and installation space/layout are frequently a restriction. For instance, online X-ray analysers for process control introduce a delimitation error by the nature of X-ray physics. Thus only in special cases a relative accuracy better than three per cent relative, as one standard deviation, is achieved. A sampling system for process control needs not to be, as representative, for so many sample properties, as one for composite laboratory analysis samples. Sampling system maintenance is also an important issue. There are many sampling systems in the industry which have been difficult to maintain and are in disuse for lack of resources or incentives to keep them running. Pierre Gy developed the most generally accepted sampling theory. One of the main principles is that all particles in a one-dimensional process stream should have equal chances of being included into the sample. A correctly designed and operated transversing cutter comes close to this goal but has limitations in temporal representativity. For slurries an acceptable solution in many cases is to use a fixed vertical cutter(s) in a position where the slurry is well-mixed by turbulence and other means. For online analysis, reliability problems are mostly related to faulty design or installation of the piping system to the analyser. Properties of material processed, process flow sheet and piping details before and after the sampler have to be taken into account when deciding on which sampling arrangement is appropriate. Guidelines and some solutions to these issues are presented in this paper.

Mar 1, 2010

By MattelmSki M

Outokumpu Harjavalta Metals Oy has been producing nickel since 1962, based on conventional flash smelting technology followed by electrowinning of nickel. In the 1980s, a research project was initiated to develop a converterless direct smelting process to produce matte for further refining in the then existing refinery. The process was tested on a pilot plant scale at Outokumpu's research centre in Pori and was found to be viable. The process was named the Direct Outokumpu Nickel Smelting Process or the DON Process. At the turn of the 1990s, Outokumpu studied various options to develop its nickel business and the Harjavalta operations. As a result of this work, the DON Process was further developed to produce two mattes: low iron matte in the flash furnace to be leached in the existing leaching circuit and high iron matte in the electric furnace to be leached in the new leaching circuit. In Harjavalta's case, it was essential and important that the process could use the existing flash furnace and electric furnace without converters.

Jan 1, 1996

The Henty Gold Mine is a good example of a situation where conditional simulation and optimisation techniques may have useful impact on modelling of mineralisation distribution and ore definition. Much of the gold mineralisation at Henty is concentrated within an alteration zone which is both physically discontinuous and forms only a small fraction of the overall mineralised volume. The alteration units are mappable from diamond drill core and underground workings. Conditional simulation and optimisation techniques for ore definition have found considerable success in the open pit gold mining environment. For many reasons including computational efficiency, lack of consistent geological information, and lack of familiarity with ideas and methods among mine geologists, implementations of these methods in open pit mining have been comparatively simplistic. Modelling is commonly reduced to treating the sample data as a single geologic population. This paper discusses the application of the MP method (a particular implementation of conditional simulation and optimisation) to modelling the distribution of potential ore blocks in the Henty gold mineralisation. The approach allows the mine geologist to model both the spatial geometry of the alteration types and the gold grades associated with each alteration type in a single process. Options allow the geologist to include or exclude underground geological mapping and face sampling depending mainly on the abundance of drill hole sampling and the quality of the face sampling. An optimisation algorithm based on maximisation of profit from mining is used to assist in ore definition.

Jan 1, 2000

By M G. Shaw, M A. Rhamdhani, S P. Singh, A R. Duffy, B Eisenbart, A K. Shukla, G A. Brooks

The field of astrometallurgy is a growing area of study. Metal production on the Moon is likely to begin in less than a decade as major space agencies such as NASA (National Aeronautics and Space Administration) and CNSA (China National Space Administration) are preparing to construct permanent lunar bases. The utilisation of regolith to generate oxygen and metals is expected to be important in the development of a sustainable lunar habitat. This paper provides an overview of potential metallurgical processing methods for lunar conditions, emphasising the impact of lunar factors on slag chemistry. The interaction between regolith and the extracted metals, as well as their impact on slag composition and refractory performance, are critical considerations in metal production on the lunar surface. The initial research on lunar metallurgical technologies is focused on oxygen extraction and Fe-Si alloys are reported as the by-products of these processes. This paper delves into the fundamental thermodynamics associated with the carbothermic reduction of lunar regolith. Thermodynamic analysis using the FactSage™ ver 8.2 software package indicates that the Fe-Si alloy can be produced as a metallic product from the lunar regolith at temperatures ranging from 1400°C to 1600°C under terrestrial conditions. However, under ultra-high vacuum conditions (3 × 10-15 bar) on the Moon, the required operating temperature for producing ferrosilicon would be significantly reduced. Thermodynamic modelling results indicate that under lunar vacuum conditions, Fe-Si alloys only exist as solid phases at lower temperatures below 650°C. At higher temperatures, both Fe and Si are expected to be present in the gas phase. In this work, the carbothermic reduction of the Lunar Mare Simulant (LMS-1) is conducted under terrestrial conditions. The findings indicate that the process can readily yield Fe-Si alloys with 7–10 wt per cent Si at 1600°C. Additionally, energy dispersive spectroscopy (EDS) analysis of the resulting Fe-Si alloy indicates the presence of phosphorus up to 1 wt per cent.

Aug 21, 2024

By F Brenguier, R A. Lynch, G Olivier

The seismic velocities of intact rock are dependent on the applied stress. Unfortunately, the low susceptibility of seismic velocity to stress changes mean that changes in seismic velocity have to be measured extremely accurately to infer stress changes from them. Previously, it was thought that measurements of this accuracy could only be made with active sources or repeating earthquakes. In this paper, we show that the noise generated by mining activity can be used to construct virtual seismic signals with which we can measure changes in seismic velocity accurately enough to see the short- and long-term effects of a production blast on the surrounding medium. The time-dependent velocity variations achieved with this method show that the blast caused weakening of the rock mass for the rock within a radius of 200 m of the blast. The weakening is healed by confining stresses over a period of five days, after which permanent changes in the seismic velocity can be seen. The size and spatial distribution of the seismic velocity changes were compared to modelled changes in static volumetric stress, which supported the notion that seismic velocity changes can be used to measure the redistribution of stress after a blast. The results of this study indicate that this method can be a powerful tool to evaluate the evolution of stress in a mine at a relatively low cost as the data that it uses would normally be discarded.CITATION:Olivier, G, Lynch, R A and Brenguier, F, 2016. Measuring the redistribution of stresses resulting from new excavations with ambient seismic noise correlations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 873–878 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016