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By M Scoble, E Rubio

The re-engineering of manufacturing production systems has demonstrated the benefits from using production information for optimising processes. This paper explores the techniques and issues in the acquisition and analysis of mine production data for tactical decision making in production control. The use of information and operations management tools is presented in the context of block caving studies, with particular focus on the relationship between secondary breaking and LHD production performance.

Jan 1, 2000

By G Capes

A novel open stope design approach is presented that delivered improved performance in a mining area with poor ground conditions at the Olympic Dam mine. During 2019, a large open stope had an unplanned caving event resulting in the inability to extract the planned tonnes and subsequent sterilisation of nearby stopes. A design limitation was the lack of data and understanding around the alteration domain extents, the rock mass strength controls and limits, the failure modes controlling stope stability in the local area, and the use of conventional stope shapes. From the available data and failure observations, it was inferred that the dominant caving failure mode resulted from a blocky rock mass impacted by structure and alteration causing an unravelling failure mechanism. Numerical and empirical analyses were conducted to test this hypothesis and establish strength limits for design. The strength limits for the design were then used to provide a range of outcomes from which future stope design shapes such as chamfered backs could be selected. Three alternate chamfered geometries were selected to trial the innovative designs. The application of this methodology in 2020 resulted in overbreak reduction from >100 per cent in the initial caved stope to

Mar 29, 2023

By P K. Wong, D A. F Oliveira, F M. Azad

In situations where foundation piles are located in proximity to existing or future tunnels, it is typical for the tunnel owner to require that sleeving of the piles be carried out to at least the invert of the tunnels to minimise any load transfer to the tunnel lining. In competent rock, this practice may be sometimes unnecessary, thus uneconomical. This paper presents an assessment of the effect of pile loading from one of the multi-storey buildings at Barangaroo South in Sydney on the adjacent future Sydney Metro tunnels. It was originally required by Transport for NSW (TfNSW) that the piles be sleeved below the tunnel invert level; however, the building developer wanted to reduce the pile sleeving depth to achieve a more economical solution due to the large number of load transfer piles being required for the project. To assess this feasibility, a full 3D commercial numerical code, FLAC3D, was used to carry out this complex soil-structure interaction analyses. Based on these assessments, it was demonstrated successfully to the TfNSW that the pile sleeving may be terminated at 2 m above the tunnel invert level. For this arrangement, the investigations found that the loading on the piles should have negligible adverse impact on the tunnel lining design. As a result of such an assessment, the proposed pile sleeving level was approved by TfNSW, thus offering an economical foundation solution for the project.CITATION:Azad, F M, Oliveira, D A F and Wong, P K, 2014. The impact of pile loading on adjacent metro tunnels – Barangaroo South, Australia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 355–360 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Ward M

The current and future requirements for an underground mine information management system are being met with a flexible, value-engineered approach to mine information/communication infrastructures. El-Equip has developed and delivered to over fifty mines around the world an integrated, high capacity, radio-based leaky feeder communication system called MultiCOM. To meet the requirements of recently developed advanced information management technologies, such as production and ventilation management, the system has evolved to support simultaneous mobile and fixed information delivery services over an integrated single cable system. The following paper will review how MultiCOM is enabling information/communications technology to cost-effectively implement mine monitoring and control applications. Applications described in this paper include mobile vehicle production tracking, vehicle location, ventilation system monitoring and control with integrated ventilation system simulation. The techniques described are leading the world in terms of flexible and value-engineered applications of technology in the underground mine.

Jan 1, 1995

By M I. Pownceby, M A. Rhamdhani, S Palanisamy, D Fellicia, B Satritama, G A. Brooks, A Ang

Metal production have long been using carbon sources as both reducing agents and energy sources. Consequently, the global extractive metal sector contributes significantly to greenhouse gas emissions, accounting for approximately 9.5 per cent. Hydrogen gas offers as a promising ecofriendly alternative to carbon in metallurgical processes, serving as both a reductant and energy supplier with a by-product being only water vapour. However, the implementation of molecular hydrogen faces certain challenges related to the thermodynamics and kinetics of metal oxide reduction. In addressing these challenges, researchers have explored the application of hydrogen plasma, generated by subjecting molecular hydrogen to high energy to produce atomic, ionic and excited hydrogen species. Hydrogen plasma offers thermodynamic and kinetic advantages over molecular hydrogen and carbon-based reductants, exhibiting lower standard Gibbs free energy of reaction and activation energy. Therefore, hydrogen plasma can produce metal in fewer steps, process any oxide feed and feed size and even be used to refine metals. Despite these advantages, challenges exist in utilising hydrogen plasma in extractive metallurgy, including electricity costs, potential reverse reactions and industrial-scale implementation. This study provides a mini review of prior research on hydrogen plasma for metal oxides reduction, particularly iron oxide, as well as state-of-the-art techniques for its use in extractive metallurgy applications by mentioning several reactor types. Future prospects and scale-up possibilities of the hydrogen plasma in extractive metallurgy will also be presented.

Aug 21, 2024

By I Swane, R Rait, A Robertson

Geochemical assessment of mine waste materials prior to commencement of a proposed mining operation is a fundamental component of mine feasibility studies and the regulatory approvals process. Static and kinetic geochemical test methodologies are widely used to predict the geochemical nature of mine waste materials and to develop strategies for managing potentially æhostileÆ materials. These data can also be integrated with data from other fundamental studies such as hydrogeology to predict specific environmental outcomes and potential impacts at mine closure and post-closure.A case study is presented for a proposed open pit gold mine in Mongolia, which illustrates how geochemical, hydrogeological and groundwater quality data can be used as part of a geochemical modelling process to predict the final pit lake water quality over time. A series of static and kinetic test geochemical test programs were completed and acquired data integrated with hydrogeological and groundwater quality data provided by the proponent. A widely used geochemical modelling program (PHREEQC) was used to develop the geochemical model and predict water chemistry in the pit void after mine closure. Sensitivity analyses were completed to explore the effects on the model output of groundwater to leachate water ratio, pit wall rock type and climate.Modelling has indicated that pit void water should be pH circum-neutral at mine closure and should remain within Mongolian and World Bank water quality guideline limits under the modelled simulation most likely to occur in the field. Final void water salinity is expected to increase eight fold over 14 years after end of mine life due to a continuous flux of salts (particularly sulfate salts) into the pit lake whilst the pit lake volume will remain relatively constant due to evaporation and a slow recharge rate. Dissolved metal and sulfate salt concentrations in pit water are also predicted to increase over time and could be moderately elevated compared to applied water quality guideline values. Some of the metal concentrations, however, may be lower as these would be expected to precipitate at circum-neutral pH and greater. Recommended additional assessment work on the project when mining commences includes determining the magnitude of adsorption and co-precipitation of metals occurring in the pit void water/sludge system.CITATION:Robertson, A, Rait, R and Swane, I, 2013. Geochemical assessment of mine waste materials and prediction of final pit lake water quality at a proposed gold mine in Mongolia, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 165-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By S Maritsa, E K. Chiwandika, S M. Masuka

The iron and steel industry is experiencing an increase in the use of iron and steel commodities within societies, decarbonisation pressures, depletion of high iron ore grades and high energy consumption. This necessitates scrap metal recycling, low-grade ore utilisation using the induction or electric arc furnace to achieve the global target of net zero CO2 emission. The available highquality scrap metal cannot sustain the steel industry but the world has unused hematite-goethite ores. It is the aim of this research that this resource be utilised using the induction furnace to sustain the steel industry in an environmentally friendly manner. Indurated pellets prepared from the hematite-goethite ore, 5 wt per cent limestone and 5 wt per cent coal addition were smelted in the induction furnace at 1350 ± 50°C with 25 mins holding time. The effects of basicity and carbon content were also investigated to optimise the smelting parameters. The results showed that the careful control of the basicity, and iron-to-carbon ratio maximised total metal recovery. The optimal basicity ratio was determined to be 1.3 and a carbon to iron ratio of 1.4 achieved a total metal recovery of 73 per cent. The metal recovery was closely related to the estimated slag melting temperature. The basicity ratio of 1.3 achieved the lowest slag melting temperature estimated to be around 1380°C based on the CaO-SiO2-Al2O3 phase diagram. The recovered metal had a comparable chemical composition and microstructure to that products from an ITmk3 furnace.

Jun 19, 2024

By P Gomez, R Baumgartner, G Escobar

"The Cerro Corona mine consists of a Cu-Au porphyry deposit located in the Andes of northern Peru. The deposit comprises a typical Cu-Au multiphase porphyry mineralisation that has been overprinted by an epithermal event. This has generated a complex pattern of argillic alteration facies, which was accompanied by a locally structural-controlled Au-Cu mineralisation with the presence of gold and limited Cu sulfides and sulfosalts. These features, along with the porphyry-style mineralisation, produced a multifaceted occurrence of gold.Since the beginning of operations at Cerro Corona in 2008 there has been a continuous improvement of the geological and mineralogical knowledge. All mineralogical studies have mainly focused on host rock types and, to a lesser extent, alteration minerals, but little work has been done on the mineralisation itself. As a consequence, limited mineralogical information was available for use in the process optimisation initiatives.In the last two years, a series of mineralogical characterisation studies were undertaken with two main goals. First, to gain an understanding of the mineralisation genesis and second, to obtain a detailed characterisation of copper and gold minerals to support ongoing process optimisation. The first goal was achieved by conventional optical microscopy while the second required electronic microscopy and other microanalyses due to the necessity of quantifying several minerals of interest for the processing.The results were used to refine pre-existing geometallurgical domains, explain copper and gold losses in the flotation process and to some extent, improve copper and gold recoveries. The mineralogical characterisation is an ongoing work. Mineralogy provides the basis for any optimisation exercise since it looks in detail at the material to be treated and therefore, should be part of all geometallurgical programs.CITATION:Baumgartner, R, Gomez, P and Escobar, G, 2016. Comprehensive Mineralogical Characterisation at the Cerro Corona Cu-Au Porphyry Mine – the Fundamental Key for Geometallurgical Applications, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 221–230 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By R S. Sing, M D. Yadav, G Udaybhanu

This paper presents the results of the first part of a research project to study the effect of various inhibitors to reduce the spontaneous heating susceptibility of some highly susceptible Indian coal seams. In this investigation 11 inhibitors were chosen and applied at three, five and ten per cent of their concentrations in an aqueous solution for four coal samples collected from four different seams. The susceptibility of coal samples, before and after application of these inhibitors, was determined by carrying out crossing point temperature (CPT) analysis. The findings of this study have indicated that it is possible to retard the tendency of spontaneous heating of Indian coals to a considerable extent by the application of six of the inhibitors studied. Further, these inhibitors were tested in 1:1 combination to study their synergistic effect. Finally the economics of the application of these inhibitors has been analysed and four inhibitors are recommended for field use. These results have direct application to control fire and improve productivity and safety in coal mines.

Jan 1, 2005

By B Bonfils, P Lois Morales, C Evans

One of the main challenges for current and future mining and processing methodologies is to understand the characteristics of the rock so that its behaviour in one or more parts of the mining process chain can be predicted. Features such as rock texture, mineralogy or border complexity between minerals control how the rock behaves from the processing plant through to the final products, including tailings disposal and thus can affect the feasibility of the project from technical, economic and environmental impact perspectives. Understanding how the mineralogy and texture of rock affect its behaviour in mineral processing is a demanding area of research and is essential knowledge in predicting the processability of complex ores in different stages. This study aims to demonstrate that different types of relevant information can be extracted from a range of currently available analytical methods. However, this information can be used in a complementary way for building a more comprehensive rock characterisation at the microscale and better-predicting ore processing characteristics from the intact rock through to tailing disposal. CITATION: Lois Morales, P, Evans, C and Bonfils, B, 2018. Multisource rock characterisation at microscale for a better understanding of processing characteristics, in Proceedings Complex Orebodies Conference 2018, pp 44–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By K G. van den Boogaart, M Lehmann, U Mueller

Geometallurgical parameters are descriptions of the mineralogy and microstructure of the ore determining its mineralogical and microstructural characteristics. From a conditional geostatistical simulation of such properties, a processing model can compute recovery, equipment usage, processing costs, and thus the monetary value for mining and processing a block with certain processing parameters. The output can be used for optimising mining sequences or finding optimal processing parameters by solving the corresponding stochastic optimisation problem.The approach requires two properties of the simulation not provided by established geostatistical techniques:Many relevant geometallurgical parameters are from non-Euclidean statistical scales such as (mineral) compositions, (grain size) distribution, (grain) geometry, and (stratigraphic type) categorical, which might produce nonsensical values (for example, negative proportions, negative facies probablities, planar grains) when simulated with standard geostatistical techniques.Due to the nonlinearity of processing, the entire conditional distribution of the geometallurgical parameters is relevant, not only its mean and variance. The geostatistical simulation needs to reproduce the joint conditional distributions of all the geometallurgical parameters.The multipoint conditional geostatistical simulation technique discussed here allows for jointly simulating dependent spatial variables from various sample spaces. The technique combines an infill simulation, similar to the one used in multipoint geostatistics, with a new form of distributional regression to estimate conditional distributions of arbitrary scales from different information sources, including training images, training models and observed data. The distributional regression is based on a generalisation of logistic regression and is related to both Bayesian Maximum Entropy geostatistics and high order cumulants.The method ensures that simulated data reside in the set of possible values and honour the characteristics of the joint distribution to be reproduced. The computational effort is substantial, but affordable for a useful application with standard problems: from processing-aware block value prediction and block processing optimisation as shown in the test application to a mathematically completely defined simulated model situation with a complex processing model.CITATION:van den Boogaart, K G, Tolosana-Delgado, R, Lehmann, M and Mueller, U, 2014. On the joint multipoint simulation of discrete and continuous geometallurgical parameters, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 379–388 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By C Parihar, R Garg, A Bhandari, S Bhandari

Blasting can impact the efficiency of entire downstream mining operation. Individual technology solutions for blasting have been available in the industry for many years but all of them only cater for certain aspects of blasting. Many of them are based on individual research and/or experiences. Some of the available software solutions are not suitable to be used in the field as that they need advanced skills or tools. Also, most do not take technology advancements like mobility, advanced data analytics, web solutions and integration into consideration. Hence, no technology platform is currently present in the industry that addresses all potential needs a blaster may need in an integrated manner.This paper presents an integrated solution that takes care of all aspects of blasting – design blasts according to mine plan; collect data after drilling has been carried out (as there is often difference in designed and actual drilled hole locations in the field); predict blast results in terms of fragmentation, flyrock, ground and air vibrations, wave front reinforcement and flyrock distance; and after assessment, allows changes in charging, delay timing and sequence. The technology solution is a secure, cloud-hosted, web-based software-as-a-service solution that can be accessed from anywhere. Also it has a mobile app, which is available for both Android and iPhone/iPad. The mobile app is also integrated with the web-based solution using application programming interface calls to the central data repository.Case studies for two limestone mines are presented where this solution is being used in its initial format. This software platform enabled analysis of the outcome from a previous blast pattern and then subsequently allowed optimisation of blasting operations based on historical data. Uses of this platform have resulted in improved key performance indicators in these two limestone mines. The mobile app as part of this platform enables extensive field blast data capture and analysis and also various predictions before a blast. Data collected include blast parameters, individual hole charging, initiation pattern, videos, photographs and vibration records for analysis/reporting. The key features of the solution are a blast designer, a detailed blast data collection/analysis and a series of environmental predictors. These predictors give blast results in terms of fragmentation, flyrock, ground and air vibrations and wave front reinforcement and take remedial steps before blasting to optimise and control adverse environmental impact. Many features, such as fragmentation predictor and mobility solution, are completely unique features that are not available elsewhere in such a field personnel-friendly manner.CITATION:Bhandari, S, Parihar, C, Garg, R and Bhandari, A, 2015. An integrated technology solution for optimised and environmentally-controlled blasts, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 393–400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The Wattle Dam gold mine, located near Kambalda in the Goldfi elds region of Western Australia has recently progressed to an underground operation and is now believed to be Australia's highest grade operating gold mine. At end of March 2010, the deposit had reserves of 132 000 t @ 20.8 g/t for 88 000 oz and by the end of June 2010 had produced 110 000 oz from open-pit and underground mining. The Wattle Dam main lode is characterised by very coarse gold mineralisation. Gold occurs as cm to decimetre fracture fi ll veinlets, shear surface coatings and erratic fl akey clusters. The gold has no quartz or silica association and lacks adjacent low-grade mineralisation or alteration assemblage. Geologically it appears atypical of Archaean lode gold deposits and may represent an extreme end member of the type. Definition of the lode is largely dependent on effective geological identification of the host lode zone and an understanding of the erratic distribution and grade behaviour of a high-nugget, coarse gold deposit. Dependence on assay data to defi ne the lode zone would result in the deposit being mined incorrectly and much of the deposit being left unexploited. This paper discusses the geology, coarse gold characteristics and defi nition methods which are used to successfully defi ne and mine the deposit.

Aug 1, 2010

By W Newton, J Price

This paper outlines the design, justification and performance of a gravity circuit upgrade at the Marvel Loch treatment plant. The design of the upgrade was simple but effective. The key components of the upgrade were the addition of a sluice and a second Knelson Concentrator. The sluice was installed as a pre-concentration step. The upgrade also included the purchase of a Mineral Cone to treat the increased quantity of gravity concentrate. The cost was low because of the use of mostly second-hand equipment. The result was that for a cost of $75 000 the gravity recovery doubled and the overall recovery increased by over one per cent. This paper shows that you do not need to spend millions of dollars to be innovative and successful.

Jan 1, 2000

By D J. Gray

The 4 km long Huguenot Toll Tunnel in the Western Cape region of South Africa celebrated its tenth anniversary on 18 March 1998. At present a single (South) bore with bi-directional traffic flow is operational. The North bore was originally excavated but not lined and equipped.The tunnel is fitted with a semi-transverse ventilation system comprising 45/350 kW two speed fresh-air and 1 MW exhaust air fans at each of the portals. These provide ventilation through fresh and exhaust air ducts above the ceiling separated by movable partition doors. Secondary air ducts deliver air at low level. The fan control depends on the levels of CO pollution or visibility measured at six positions along the tunnel.The system performed well during initial tests and under conditions of low traffic volumes. As traffic volumes increased, and user complaints of bad air in the tunnel were received on several occasions, we realised that we had a problem. Tests confirmed that natural airflow within the tunnel induced by prevailing meteorological conditions outside the portals affected the performance of the ventilation system causing a plug of bad air to be trapped at varying positions along the operating tunnel.The control systems in the tunnel are presently being upgraded as described by Gray, Rieckert and Bullock (1998). As part of the retrofit we are implementing a new control strategy for the ventilation system which takes into account the external weather conditions. This paper discusses the 24 month long meteorological data gathering exercise, which is on-going, and explores the philosophies planned for controlling the ventilation system. The correlation between winds external to the tunnel and induced airflow inside the tunnel are examined. The effects of the weather induced airflow on the existing ventilation system are considered and proposals given for taking these effects into account in the new control strategy. These include the implementation of an expert system to predict ambient airflow from prevailing weather conditions, and the use of airflow measurements taken in the uncompleted North bore as a cross-check.The paper highlights the need to take cognisance of external weather conditions when designing tunnel ventilation systems.

Jan 1, 1999

By K Haroon, J D. Speed, S P. Wood

Online analysis of continuous and batch processes has seen a dramatic increase in recent years, with examples ranging from petrochemicals to pharmaceuticals, to industrial biotechnology and food and drink. The particularly challenging environment of alumina processing has meant that instrumentation needs specific features and characteristics to be truly suitable, features such as: robustness, resistance to caustic conditions both in the analyte and the ambient environment, and reliability for long-term continuous use. Here we present the development of a novel FTIR spectrometer that achieves these requirements through the use of a static optics arrangement of mirrors, and stable diamond-tipped light-pipe probe. Firstly we give a very brief explanation of spectroscopic analysis, and the difference between FTIR and other infrared methodologies. Next we outline the novel arrangement of mirrors required to produce an interferogram without moving mirrors, and compare the benefits and drawbacks of this approach instead of conventional designs. We then share the results of laboratory analysis of synthetic Bayer liquors, with detection limits for aluminium hydroxide, sodium hydroxide, sodium carbonate and various sodium salts of organic acids. We then share the results of analysis on production samples, both in idealised laboratory conditions and then online in the process itself. Lastly we present work on in situ ultrasonic descaling solutions to avoid scale build-up and provide continuous cleaning of the probe – preventing the need for probe removal and manual cleaning.

Aug 24, 2022

By R Justa Cámara, J María Bertrán Llop

"The need for suitable geotechnical characterisation of the rock mass for underground construction is evident. The enlargement project of Railways of the Generalitat of Catalunya (FGC) in Sabadell is a patent example.In general, it is uncommon to encounter problems in the identification and characterisation of certain relevant weak rock formations, which affect project designs. However, all materials should be properly studied, as mischaracterisation can lead to a suboptimal design, resulting in construction problems during the course of the work.Good quality rock is generally not difficult to characterise, but this is not the case for Quaternary or Tertiary cemented soils. Geotechnical investigations based on boreholes do not provide enough information because samples are often badly damaged during the drilling process, if appropriate techniques are not taken. The samples can be altered and may not be representative of the in situ?material.The design and construction of the extension to the FGC line in Sabadell highlighted the importance of the characterisation of Quaternary and Tertiary cemented soils, in particular their rigidity and its underestimation. The twin tunnel project had a total length of 5.1 km, including five stations with 3.5 km excavated by tunnel boring machine (TBM). The remaining 1.6 km was constructed using cut and cover methods. The TBM portion of the tunnel had a bored diameter of 6.83 m with an internal radius of 3 m and 0.25 m thick precast concrete segments. Much of the tunnel alignment passed through and was affected by the presence of certain stiff layers of Quaternary cohesive materials.In this paper the TBM challenges faced will be discussed in detail. In particular:  TBM excavation rate reductions and overheating problems due to the required excessive thrust and torque floating problems in the lining due to nil earth pressure over the rings and the development of an improved, controlled setting time mortar to address this issue block-in and block-out methodology for each station, in some cases with internal blocks to prevent earth pressure drops and soil scouring the relevance of performing simpler solutions, for example, hyperbaric interventions to examine the cutter wheel tools when it has been shown that interventions under atmospheric conditions were equally feasible the implementation of conventional bivalve machines as standard procedure for excavation of diaphragm walls in stations, where in fact, hydrocutter machines or pile boring machines may have been required, given the mechanical characteristics of the materials to be dug out.CITATION:Justa Cámara, R and María Bertrán Llop, J, 2014. Underground extension of the FGC line in Sabadell through cemented soils, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 161–170 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 17, 2014

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 H Hy÷tyniemi

In this paper multivariate data analysis performed on a new multi-camera system implemented to zinc flotation circuit of PyhSsalmi mine is presented. Image-analysis-based system was developed to take advantage of the commonly known fact that the changes in the flotation process are reflected to the visual appearance of the froth surface. Most often the changes are seen first in the froth and later in other process measurements. The image variables are already utilised in closed loop control and considerable savings are achieved with the current setting, but the results coming from the separate cells are used individually. This is clearly not the optimal way to take advantage of the many measurements coming from different locations of the process. A better approach would be for example to use the measurements coming from the early stages of the process to predict the behaviour (or improve the quality of measurements) in the later stages. The methods described in this paper are aimed to improving the situation in this sense.

Jan 1, 2005

By A R. Bonani, M P. Pe±a

The optimisation of slope angles, that is to say, increasing them, compared to the original design is always the subject of analysis of stability for geotechnical engineers and economic analysis for planning engineers. Questions to be answered include: What is the acceptable risk? What factor of safety? What probability of failure or reliability? The Rosario Open Pit has a history of failure, poor quality rocks and high pore pressures. It was decided to deepen the pit below the programmed design to test the practicality of different design approaches, which if successful, could be used to improve the economics of mining at Collahuasi. The revised slope design has factors of safety in the range of 1.0 to 1.2, probabilities of failure of ten to 38 per cent, and increased slope angles of between 3¦ and 5¦ with respect to the original design. The pit deepening with these design slopes will deliver an extra two million tonnes of ore which will have a significant positive impact on mining economics.

Jan 1, 2007