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A recoverable uranium resource, shown to be suitable for in situ leaching, was discovered at Honeymoon in South Australia in 1971. Exploration of the deposit was carried out during the period from 1973 to 1979. Uranium mineralisation occurs in a coarse-grained unconsolidated sand aquifer located in the Yarramba Palaeochannel at a depth of approximately 110 m. Following initial development during 1979 to 1983 and the construction of demonstration leach facilities, the Project was put on hold. Southern Cross Resources purchased the Project in 1997. Government approval was received in March 1998 for the operation of on-site demonstration leach and recovery facilities while an Environmental Impact Statement was prepared and a 1000 tpa commercial production plant was designed. The Environmental Impact Statement (EIS) was released in June 2000 and operation of the test facility was completed in August 2000. Acceptance of the EIS by Commonwealth and South Australian state governments was announced on 20 November 2001. A Mining Lease was granted over the area of the proposed ISL operation on 8 February 2002. Operation of the Project is entirely dependent on using highly saline underground water resources to supply process and human needs. The management of discharge streams from the plant by re-injection was approved. The Honeymoon demonstration plant was the first adaptation of the solvent extraction process to highly saline in situ leach solutions. As such, it incorporated a number of unique operating and installation features. The trial period enabled optimisation of the process chemistry, additives and management and serves as an invaluable base for the proposed plant design and future operation. This paper discusses the nature of the uranium occurrence, the effect of saline water on the leach process and equipment, project design and environmental considerations, the requirements for disposal of discharge streams to minimise the impact on the arid environment and the requirements for rehabilitation following project completion.

Jan 1, 2002

By I D. Gregson, A S. Garcia, K M. MacAndrew

The design work undertaken by Rock Mechanics Technology (now part of Golder Associates (Golder)) has played a major part in successfully establishing mechanised room and pillar working in Indian coalmines, both for the development of new districts and for the re-establishment of old districts prior to pillar extraction on panel retreat.Golder has used appropriate design of pillars, extraction sequences and final snook sizes to minimise ground control risks during pillar extraction. Where the strata will not cave reliably, partial extraction systems leaving either a crush pillar or a substantial yield pillar have been adopted.Remote monitoring of selected pillars during the extraction process using stress cells, extensometry and convergence measurements provides confirmation of pillar behaviour and verification of designs.A new telltale device, giving a visible warning of impending caving, is now installed at all Indian pillar extraction sites and is proving very successful.CITATION:MacAndrew, K M, Garcia, A S and Gregson, I D, 2014. Coalmine pillar design and performance during mechanised pillar extraction in India, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 347–358 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By F Rashidinejad

Iran has had an active mining sector for some 7000 years. Exceptional in terms of its mineral diversity, Iran produces 62 minerals, and is ranked among the world’s 15 most mineral-rich countries. Many people around the world know Iran as one of the major petroleum exporters. Oil and natural gas dominate Iran’s economy, and oil exports provide the principal source of income, contributing more than 80 per cent of foreign exchange earnings. Transformation of Iran from an oil exporter to an independent country to oil has been on the table for many years, even before the Islamic Revolution of 1979. Development of the Iran’s mineral industry is one of the major replacements for petroleum exports. In the last decade, Iran invested billion dollars in the mining and mineral industry sectors and to increase the added value, tried to export processed minerals instead of the raw materials. In accordance with the ‘20-year Perspective 2025’ that targeted by the Supreme Leader, Iran will be a country with the first rank in economy, science and technology in its region. The objectives over this perspective include briefly increasing annual production to 55 Mt of crude steel, 800 000 tonne of copper cathode, 1.5 Mt of aluminium, 200 Mt mineral products, 300 000 tonne of zinc and 5 000 kg of gold. These goals are achievable in normal circumstances, but concurrency of the 20-year Perspective 2025 with commencement of the UN Security Council sanctions against Iran, frustrated objectives of the perspective, at least the ones related to the mining and mineral industry sectors. This paper tries to elaborate the development programs and following challenges for the mining activities of Iran by 2025.

Nov 22, 2011

By J Pan

This case study assesses the application of Mine-to-Mill optimisation combined with Whittle Consulting’s Prober<sup>®</sup> economic optimisation for the purpose of economic value uplift in open cut base and precious metal operations. The study extends the application of these optimisation methods to incorporate the recent practice of Ultra High Intensity Blasting (UHIB) developed by Orica Mining Services. The case study deposit known as “Marvin” is a copper/gold porphyry resource that is commonly used in optimisation software training and industry case studies. It has many similarities to Newcrest’s Cadia Hill open pit mine in NSW. Prior desktop research and industrial trials employed static assessments of Mine-to-Mill effects. No prior work other than a Whittle Consulting client study, has sought to assess the impact of variable fragmentation on enterprise economic value. This study examines the use of variable blasting intensity as a driver of economic value maximisation over the mine’s life.CITATION: Howe, S and Pan, J, 2018. Application of enterprise optimisation considering ultra high intensity blasting, in Proceedings Complex Orebodies Conference 2018, pp 14–20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By D G. Rantucci

Organic carbon is a major ore contaminant at MMG’s Century mine. This carbonaceous matter is associated with shale hosted sphalerite mineralisation. It occurs as elongated lamellae and as inclusions in porous sphalerite aggregates which are fine grained and difficult to liberate from sphalerite. The carbon prefloat circuit was designed to remove the liberated organic carbon in order to mitigate excessive reagent consumption, contamination of the lead and zinc concentrates and poor flotation performance in the primary zinc circuit. The consequence of organic carbon removal is that sphalerite and galena minerals are lost to the prefloat concentrate. A Jameson Cell was installed in late 2005 as a prefloat cleaner cell. Operational experience showed that the cell became capacity limited during periods of high amounts of organic carbon in the feed and was subsequently bypassed.Reactive style operating strategies were implemented to manage the effects of insufficient organic carbon removal by the prefloat circuit but due to the relatively large circuit residence time, upstream changes meant hours before the downstream circuits were stabilised following a disturbance from excess carbon.This paper describes the modifications and testwork undertaken to enable the Jameson Cell to be operated during periods of high organic carbon in the float feed and the implementation of process control initiatives to proactively remove the required prefloat mass from the float feed to eliminate the reactive style operating strategy.The process control modifications centred on dynamically targeting a prefloat mass recovery determined by an equation relating the carbon to zinc ratio to the carbon prefloat mass as a percentage of the float feed. The equation was developed by analysing historical data. These improvements served to optimise the prefloat circuit and consequently stabilise the downstream lead and zinc circuits.

Aug 8, 2011

By B Kilgariff

Flotation has been in use at Broken Hill for nearly 100 years, and the process has gone through many different optimisation studies over that time. This paper reviews the current flotation practice at the Perilya Broken Hill Mine, and details one of the recent optimisation studies conducted using mathematical modelling and simulation tools. The optimisation study consisted of surveys of the lead and zinc circuits, mapping of the floatability components of the ore and developing models of the lead and zinc circuits. The models were then used to conduct simulations to simplify the circuit. The study allowed plant personnel to identify optimum operating conditions for their current flotation cells, as well as possible improvements in circuit configuration and cell capacity.

Jan 1, 2005

By W Y. Kim, Y B. Kang, Y J. Park

The phase equilibria in the Al2O3–TiOx system were investigated in wide ranges of temperature and oxygen partial pressure: 1300~1600°C and 10-16.6~10-8 atm, respectively. The equilibrium phases and their compositions were identified using X-ray diffraction (XRD) and electron probe microanalysis (EPMA), respectively. Most noticeably, a wide range of pseudobrookite solid solution was found in equilibrium with almost pure alumina. At each temperature, the cationic ratio expressed as RTi = nTi/(nAl + nTi)) of the pseudobrookite solid solution showed a noteworthy dependency on the oxygen partial pressure. This resulted in the formation of a broad range of pseudobrookite solid solutions, ranging from Al2TiO5 (RTi = 1/3) to Ti3O5 (RTi = 1.0). Complete miscibility within the pseudobrookite solid solution was observed at 1600°C, with only a minor miscibility gap becoming evident below 1500°C. Based on the results obtained in the present study, the behaviours of Al2TiO5 pseudobrookite have implications in two key domains: (1) understanding changes in the physical properties of the materials, and (2) elucidating the evolution of Al–Ti complex oxide inclusions in liquid steel which can deteriorate the steel cleanliness.

Aug 21, 2024

By B Saunders, J Carpenter

PanAust’s Phu Kham copper-gold operation (Phu Kham) in Laos is currently limited by throughput in the Semi Autogenous Grinding (SAG) mill. The ability to accurately predict SAG mill throughput (throughput) is therefore critical to accurately forecast copper and gold production. During the fourth quarter of 2016 the proportion of hard unweathered rocks in the mill feed increased, resulting in a period of lower than expected throughput. These low throughput rates prompted a study with the aim of identifying a practical solution for throughput predictions. The study identified an empirical modelling approach based on actual SAG mill throughput rates. The empirical model was then optimised by linear programming to identify the ideal feed blend of unweathered rocks to achieve a maximum SAG mill throughput.Rock strength was the initial focus of the throughput study at Phu Kham because previous studies had identified a strong link between rock strength and throughput. It was determined that there was insufficient valid data to adequately model but sufficient data to qualitatively characterise rock strength. The data identified that the weathering and lithology had a controlling influence on the rock strength. Complicating throughput predictions were operational improvements (changes to blasting and mill settings) implemented in response to the lower than expected throughput. This created uncertainty with the throughput equations. A self-learning empirical modelling method was developed to predict the throughput by incorporating fundamental rock properties with operational practices and improvements. The method is based on the proportion of mill feed with similar weathering and lithology (a proxy for comminution performance) and the actual mill throughput using the SAG mill as the analytical instrument. The modelling method simultaneously incorporated the sum and interaction of unmodelled influences including blasting, crushing and mill settings. The empirical modelling method worked at Phu Kham because the lithology and weathering has an intuitive and observable controlling influence on SAG mill throughput. The modelling method is described along with a worked example of feed blend optimisation using linear programming.CITATION:Carpenter, J and Saunders, B, 2017. Empirical mill throughput modelling and linear programming for blend optimisation at the Phu Kham copper-gold operation, Laos, in Proceedings Tenth International Mining Geology Conference 2017, pp 291–296 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By H Wright

Black Rock Cave (BRC) is a sublevel cave which was developed in 2018–2020 and has been in production since November 2020. BRC is part of the Mount Isa Mines complex and extracts a leached orebody comprising of high-grade chalcocite ore, situated below the historic Black Rock Open Cut workings. The mine is owned by Mount Isa Mines and operated under contract with PYBAR Mining Services. In 2021 a number of rockfalls occurred throughout the mine and were increasing in frequency. This culminated in a major rockfall on the decline in June 2021, after which the decision was made to withdraw all persons from the mine, initiate rehabilitation and conduct further investigations to deduce a safe method to provide long-term support. The rockfall investigations have shown that the corrosive nature of the highly leached rock mass can consume a split set in less than 18 months. A review of potential corrosion resistant ground support methods concluded that steel split sets have a safe lifespan of six months at BRC, and that all workings must have corrosion resistant support installed prior to exceeding the safe life of the friction bolts. The review recommended the use of 4 m cable bolts as the most suitable method of corrosion resistant support. This new support system, and the requirement to rehabilitate all mine workings within the leached orebody, had an impact to the schedule and an effect on both equipment and manning levels at BRC. Accelerated jumbo rehab allowed access to the production levels within two months of the rockfall. Cable bolting then followed the jumbo bolting in all leached areas. The direct impact has been ten months of reduced production, due to night shift closures of the decline to enable cable bolting. The impact to the mine has been minimised by the small flexible team that enabled the mine plan to change rapidly and often to accommodate the challenging conditions. In less than two months from the rockfall event, production had resumed. Within ten months of concluding that the mine required; full rehabilitation, a new support system and a full re-schedule, normal mining operations had restarted, with pre-event productions rates being achieved.

Mar 29, 2023

By S C. Dominy, R C. A Minnitt

Determination of the sampling constant and liberation diameter are of importance when applying the Fundamental Sampling Error (FSE) equation to optimise sampling protocols. The method for the direct determination of the sampling constant is based on the æGy 50-pieceÆ experiment and variants thereof, which is generally known as the heterogeneity test. In the coarse gold environment, the heterogeneity test is prone to poor repeatability and bias due to the very heterogeneity that it aims to quantify. A key issue is the large sample mass that can be required in the coarse gold environment, which may reach 1 t or more. The heterogeneity test often provides an evaluation of the background gold grade heterogeneity, but understates that of the high-grade coarse-gold component. This is because the total mass of fragments is usually too small to represent the mineralisation. Despite this relatively well-known problem, heterogeneity tests are often undertaken on deposits where the presence of coarse gold is ignored, not fully realised or vastly understated. Sampling types and protocol designs are frequently based on poor quality data that do not match the characteristics of the orebody. For this style of mineralisation, an empirical approach to define ore characteristics is recommended.CITATION:Dominy, S C and Minnitt, R C A, 2012. Application of heterogeneity testing to coarse gold ores, in Proceedings Sampling 2012 , pp 143-160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By García B., Wolff E.

In Colombia, northeast of Antioquia, there is a gold deposit that has produced continuously since the middle of the XIX century, located within mining title RPP-140, property of Gran Colombia Gold Segovia (GCGS) since 2010. Mining materials are taken to the “María Dama” Processing Plant where 1500 tonnes of materials are processed daily. Before 2010, the previous owner of the mining title processed about 600 tpd and directly discharged almost all tailings, given that they had no capacity to put them into final deposits. El Chocho was conceived as a final tailings deposit to store the pulp produced by the processing plant; it was divided into two phases with two dams (upper dam and lower dam) given that the presence of illegal miners at the lower phase impeded a single dam design. A squatter impeded construction of the upper dam; so afterwards, starting at the higher end was necessary (owned by GCGS), building dam 1B to store tailings in pulp; after the squatter returned the lands to the owner (GCGS), construction of tailings dam 1A was required and thus complete construction of dam 1C or the upper dam. While all of this was happening, GCGS decided to acquire a 1500 tpd filter press which currently dehydrates tailings in order to take them to the valley controlled by dam 1A. Construction of dam 1A was designed following the containment wall model, made with geotextile tubes. These improvements generated reduced pressure on renewable natural resources because water is recirculated and less fresh water contributions are required; less pressure is placed on soil, flora and fauna because the area intervened for tailings storage will have a higher storage capacity and, as such, a longer useful life.

Jun 17, 2024

By G M. Zhomin, A S. Arkhipin, A Kondratiev

Viscosity of multicomponent slags is one of the crucial physicochemical properties for many industrial processes and technologies. While the viscosity-temperature relationship of completely molten slags can well be described by an Arrhenian-type law, the compositional dependence of viscosity is still not fully understood, especially in compositional regions with the lack of experimental data (eg at the glass-former concentration of 90 molar per cent or higher). In the present work major compositional relationships of the activation energy of viscous flow have been revised for numerous binary and ternary slag systems on the basis of experimental data collected and stored in the viscosity database OxiVis. For example, it has been found that the activation energy relevant to the polymerisation effect in binary systems of the MO-GFO type, where MO is the modifier oxide (ie monovalent K2O, Na2O, Li2O and bivalent CaO, MgO, BaO, MnO, PbO etc) and GFO is the glass-forming oxide (SiO2 or B2O3) is not always proportional to the third power of XGFO (contrary to the Urbain formalism) and can vary significantly dependent on the slag system. Also, the activation energy of the charge compensation effect has been revised for ternary systems of the AO-MO-GFO and AO-MO type, where AO is the amphoteric oxide (Al2O3, Fe2O3 or other). A simple polynomial model has been proposed on the basis of the carried-out analysis for estimation of viscosities of multicomponent slag systems. The model has been optimised against the experimental viscosities in the selected binary, ternary, and higher-order oxide systems and has been shown reasonable agreement with the experimental data.

Aug 21, 2024

By J Addai-Mensah, W Skinner, C Kelsey, J R. Kelly, E Baawuah

Comminution continues to be the most capital-intensive unit operation in mineral processing. The fundamental purpose of comminution is to liberate the valuable minerals so that they can be economically concentrated into saleable products. Declining ore quality characterised by lower grade and increased complexity requires significant energy consumption for comminution. Low-grade magnetite ores are typically fine-grained and require fine to ultra-fine grinding (P80 ~ 30 - 40 µm) to enhance its liberation from the typically siliceous gangue matrix. Historically, this has been achieved using multi-stage crushing and grinding technologies, which require high energy consumption with low energy efficiency. This motivated innovations in energy efficient technologies for comminution. Such technology has been developed in the IMPTEC super-fine crusher. It is an innovative, dry (with the potential to be operated wet), media-free, energy efficient crusher that can to reduce 10 mm feed particles to 19 – 30 µm with very low recycle loads. In this study, the mineralogical and physicochemical characteristics of crushed magnetite ore using the IMPTEC super-fine crusher have been investigated in comparison with those of rod milling. The super-fine crusher generated higher liberated magnetite minerals in the – 300 + 212 µm and < 45 µm size fractions compared to rod mill. Both comminution devices generated large low-grade hematite and goethite middlings. However, the rod mill produced higher locked/unliberated hematite and goethite compared to that of the super-fine crusher. Quartz mineral had the highest liberation irrespective of the comminution device used. The super-fine crusher generated higher entrapment of other minerals within the silica matrix compared to the rod mill. The breakage mechanism of the super-fine crusher which is predominantly through high compression with shear, generated improved mineral liberation in the coarse size fractions compared to the predominant abrasion and attrition breakage mechanisms of rod milling. The higher mineral liberation generated by the rod mill is potentially due to the prolonged batch milling of the ore compared to the single-pass open circuit of the super-fine crusher.CITATION:Baawuah, E, Kelsey, C, Kelly, J R, Addai-Mensah, J and Skinner, W, 2018. Mineral liberation studies of IMPTEC super-fine crusher – 130 crushed product, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 313–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By C Caris, K Fowle, M Schmid, E van Wyk, D Schofield, A Squelch, M S. Kizil

This paper has been written collaboratively by members of the International Mining VR Group. It is the first of a series of papers. Mining in the 21st century is a high technology industry that strives to reduce risk and improve safety through the use of improved processes and procedures. This risk reduction process is aligned with the innovative use of technologies often developed for other industries. Computer-based visualisation systems and their content are such innovative technologies, in particular the use of virtual environment systems and mixed reality. A primary objective of developing virtual environment systems and the mixed reality content displayed in them for the mining industry is to allow mine workers and operators to practice mine processes and demonstrate competency in tasks that will be encountered in day-to-day mining operations at mine sites. It is anticipated that providing easy access to virtual environment systems will facilitate the avoidance of high-risk situations through improved knowledge, skills, understanding and decision making. Via virtual environment systems mine workers will also be able to practice infrequent or emergency events and maintain preparedness for such events. Day-to-day mining practices can also be evaluated. The rapid pace of technology innovation and the decreasing cost of simulation hardware and software present a plethora of technology to the uninitiated. This can be confusing. In this paper taxonomy is presented that classifies hardware, what it can display and also content that can be included or displayed on the various computer-based visualisation systems. The taxonomy provides insight into where technology can and may be implemented in the future as virtual environments are a dynamic and evolving technology. The taxonomy should also assist in the decision making process when scoping or selecting technology for a particular purpose.

Jan 1, 2008

Sampling errors result from heterogeneities within the lot under study. Within a rock mass in situ heterogeneity results in the geological nugget effect, which accounts for most of the natural variability. In broken rock, constitution and distribution heterogeneities are important. A major result of the constitution heterogeneity is the Fundamental Sampling Error (FSE) which is the smallest residual error that can be achieved. It cannot be eliminated, but can be minimised and refl ects the fact that the broken rock sampling process is never completely free of error. Together with other sampling errors, FSE contributes to the total nugget effect. The FSE for a sampling protocol can be evaluated using the so-called Gy equation. Its practical applications to low-grade gold ores have often been unsuccessful due to problems linking the FSE and minimum sampling mass and the defi nition of key parameters such as the liberation diameter. Well-designed sample protocols minimise the total sampling error and hence the nugget effect. Reduction of the nugget effect is a key requirement for all sampling programs whether related to exploration and resource evaluation, metallurgical test sampling, grade control or metallurgical plant sampling. This contribution reviews the relationship between heterogeneity, FSE and nugget effect in gold deposits; and emphasises the need for FSE management throughout the mine value chain.

Aug 1, 2010

By A Dennis, T Hunter, R Coleman

For metallurgical plant design, it is necessary to progress through successive phases of test work, piloting and process development before involving all the other engineering disciplines and “freezing” the process design criteria and flow sheet. This process usually relies upon the experience, skills and personal preferences of various technology providers, study and engineering entities, test work and metallurgical laboratories and, most importantly, the owner’s team and its operators. Current industry trends include lower grades, more complex orebodies, geometallurgy in defining orebody variation and design envelopes, more common “hybrid” plant processes and the market demands for more reliable, timely and predictable early plant performance.This paper will discuss interaction of these trends and provide guidelines for the level of detail and technical complexity required for a number of different “typical” examples. The paper will pay particular attention to the study definition level translated into the required detail and certainty needed by the overall process “owner” and original equipment manufacturer (OEM) equipment suppliers to ensure the best real plant performance. Some recent case studies will be discussed. In many projects, at a late stage of project definition, it has become common practice to undertake a “value engineering” phase. Although it could be argued that this should be undertaken earlier, it is largely driven by an overall need to reduce capex and “optimise” the perceived “fat” built into the project during the detailed design process. This value engineering can be very counterproductive to project timing and operational performance and warrants discussion.The paper is intended to promote discussion on a topic of wide interest. The authors’ diverse backgrounds and experiences are integral to the views in this paper.CITATION:Dennis, A, Coleman, R and Hunter, T, 2017. Critical process design considerations from test work to operations, in Proceedings MetPlant 2017, pp 12–30 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By B Armstrong

The Proterozoic poly-metallic Trilogy deposit was discovered in 1997, and until recently, mining evaluation was stalled due to poor metallurgical performance. Unlocking the substantial economic value of the deposit required a coming together of geologists, mineralogists, metallurgists and mining engineers, who by working collaboratively, uncovered the detail necessary to allow the required metallurgical breakthroughs to occur. The deposit itself is described as a sedimentary exhalative (SEDEX), with an enriched lead-zinc-silver core surrounded by a broader envelope of copper-gold mineralisation. The geological domains were defined in broad terms based on the style of mineralisation, assay values and lithology. These domains, while adequate for the resource estimation process, failed to translate into representative metallurgical domains. Additional work with new techniques defined regions in the deposit with altered processing properties which could not be recognised by conventional geological logging. Such additional complexities could not be appreciated at the outset of the metallurgical test work program.These regions were defined by applying the EDTA analysis method for recognition of where the valuable sulfides, particularly galena, had been partially modified by oxidising conditions. Hence, the flotation response of the valuable sulfide minerals was diminished and the increased amount of heavy metal cations available in the system significantly reduced selectivity in the flotation process.Understanding the detail of this complexity was essential in determining representative metallurgical domains, which was the first step in the long road of development.

Sep 5, 2011

By T M. Brettell, D Sidea

The CSA Mine is located in Cobar, New South Wales and is operated by Glencore. Large scale underground production started from 1965, with zinc, lead, silver and copper extracted in the past. The current operations focus on copper, with a silver co-product.From 2014 to 2016, Cobar Management Pty Ltd (CMPL) undertook a major capital project to upgrade the primary ventilation system at the CSA Mine. This involved the development of ten raises using full-face raise boring from surface to a depth of 1450 m. The total length of the raises was approximately 2500 m. Geotechnical conditions were identified as a key project risk during the early planning stages of the project. Timely quantification of the geotechnical risks was required to minimise project delays and cost overruns. Geotechnical investigations were planned and conducted for each raise prior to pilot drilling and full-face back reaming.Nine of the ten raises had final wall camera and laser baseline surveys completed following full-face reaming. The surveys were conducted progressively, allowing ongoing back analysis and calibration of geotechnical evaluations as the project advanced.This paper presents the design and planning process of the raise bored excavations. It details the geotechnical investigation work undertaken to mitigate the geotechnical risks and the challenges and learnings from the project including the benefits of close collaboration between the parties involved.CITATION:Sidea, D and Brettell, T M, 2017. The CSA ventilation upgrade – geotechnical challenges and learnings, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 341–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By K M. P Singh, K M. K Sinha, G S. Jha, T Gouricharan, K K. Sharma

The majority of the powerplants in India are fed with non-coking coals, with the coals dispatched from their respective mines via wagons loaded by a rapid loading system or pay loader. The usual top size of coal is 200 mm and sampling is carried out manually from wagons. The manual method of wagon top sampling of large size raw coal is not only difficult, but also violates some of the fundamental principles of sampling. As per sampling requirements, samples are to be drawn from the full depth of the wagons, which is impossible to be done manually. Since the ash distribution in the different size fractions is not homogeneous, the results from the samples, which do not reflect the true size distribution of the lot, are likely to be biased. More importantly, sample collection by shovel from the top is a function of human discretion and not governed by the equiprobability rule. In another case, the sample has been collected by a cross belt-type auto mechanical sampler for 200 mm size coal at one of the super thermal power stations. Test analysis shows that coal collected using a cross belt-type mechanical sampler also has significant deviations from stopped belt coal samples of 200 mm size due to size segregation. Studies carried out on wagon top sampling through specially designed experiments reveal some interesting features. The presence of bias in wagon top sampling is apparent when compared with the ‘stopped belt’ sample. In this paper, a comparative study between manual wagon top sampling/auto mechanical sampling with respect to stopped belt sampling has been conducted for coal of size 200 mm. In addition, precision studies have been performed for wagon top sampling/mechanical sampling for Indian thermal powerplants.CITATION:Sinha, K M K, Sharma, K K, Jha, G S, Singh, K M P and Gouricharan, T, 2014. A comparative study of manual wagon top sampling and auto mechanical sampling of 200 mm size coal with respect to stopped belt sampling of thermal coal at Indian super thermal powerplants, in Proceedings Sampling 2014 , pp 43–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By D J. Robinson, L L. Kuhar

"Regardless of orebody value, at some stage, the pit will reach a depth where the reward for mining wider and/or deeper is not justified by the anticipated returns. ‘Last-blast’ strategies may help to some degree in recovering additional quantities of the resource but when a pit remains, there is often significant value left in the ground. In addition, in many cases, one or many good reasons may dictate why going underground and pursuing the orebody below the pit is also not justifiable. Whereas the company can hopefully move on to other more prospective parts of the orebody, the remaining options for the pit are usually very limited. Typically the pit is either held for potentially more favourable future pit expansion opportunities or it could be used for an alternative purpose, such as tailings or waste storage. This paper will present an alternative option that involves the direct extraction of values using in situ recovery (ISR) methods to recover additional value metals from the walls and/or floor of the pit. ISR involves circulating a fluid through the remaining orebody, solubilising the target metal and subsequently returning the solution to the surface for metal recovery. ISR is not the panacea to all but it has been employed selectively in the minerals industry for some time and the production of metals, such as uranium, rely heavily on this approach. ISR is not yet considered by many operators as an approach to compete with open pit or underground mining, largely because of the perceived limitations of this approach and the perceptions of risk. Rapid recent development of tools and enabling technologies relevant to ISR have made us reconsider the most economic approach to extracting many other metals from known mineral systems, even those currently listed as subeconomic. We suggest that ISR has the potential to make mine operators rethink the end of the pit life and adopt an innovative ISR approach to work toward a more complete recovery of value metals from existing pits.Citation:Kuhar, L L and Robinson, D J, 2016. In-pit In Situ Recovery - a New Approach That May Allow for Increased Value Extraction before Pit Closure, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 275–283 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016