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By C Tapia, B Hay

There is a close relationship between the mining industry, economic growth, and technological and social development. Mining activities benefit all economic agents, but only during a timespan determined by available reserves, primarily driven by internal factors such as production rate, technology and costs, and external factors such as prices determined by the market and taxes and royalties controlled by governments (Gordon and Tilton, 2008; Henckens, 2021; Tapia Cortez et al, 2018). The intense use of Mineral Commodities (MC) needed to maintain the current lifestyle has placed ore depletion as one of the main threats to sustainable economic, social and technological development. However, ore depletion does not only arise due to the finite nature of MC, price fluctuations or technological challenges. It is also triggered by the ‘economic limits of extraction’, determined by the optimisation of financial factors and technical restrictions within the regulatory framework (Henckens, 2021). Most reporting standards – if not all – define ore reserves as ‘the economically mineable part of a Measured and/or Indicated Mineral Resources’ determined by the technical and economic viability of extracting, processing and commercialising MC having the NPV as the fundamental decision – making tool (JORC, 2012; Krzemień et al, 2016). However, is the NVP an ‘economically’ basis index able to capture the complexity of economic phenomena? No, it is not, and it is crucial to define what is economic and financial. Although related, they are different disciplines. Economics studies the behaviour of the different market agents, including human behaviour and policies and explains the factors involved in the scarcity (or surplus) of goods and services. Finance focuses on financial systems and managing funds considering the time, cash available, and risk. It involves banks, loans, investments, and savings and can be considered a small subset of economics (Simon, 1959; Tapia Cortez et al, 2018). Given the economic nature of ore Reserves, endorsed by governments (Figure 1), NPV is an incomplete tool to determine ore Reserves as it limits the problem to simply maximising cash flows instead of optimising the economic benefits for all economic agents. In addition, using the rigid scheme of controlling taxation – unable to adapt to new market or economic conditions and systematically increasing – within the NPV framework only increases the sub-optimisation of ore reserves, mainly due to the systematic taxation rise. Short-term benefits of higher taxes and royalties are unlikely to offset the impacts of reducing exploration and project development in the long-term, which not only boosts ore depletion concerns but also reduces competitiveness, threatening economic and social welfare (Fisher, Cootner and Baily, 1972; Gordon, Bertram and Graedel, 2007; Lilford, 2017; Mardones, Silva and Martínez, 1985; Radetzki, 2009; Rodrik, 1982; Tan, 1987; World Bank, 2000). Holistic methods and collaborative tools, able to dynamically simulate and assess how changes in the technical settings, regulatory framework (taxes and royalties), and financial factors affect the availability of ore reserves and the impact for all economic agents, should be incorporated into the evaluation process to fill the gap.

Aug 2, 2023

By M P. Sandy, V Louchnikov, V Eremenko, M Orunesu, O Watson

"Surface support is a key component of most ground support systems which are applied as a means of reducing the risk of rockfall occurrence and maintaining serviceability of mine development. Surface support has two primary functions: distributing the applied load throughout the system by providing connection between rock bolts retaining smaller rocks that unravel between rock bolts.Confinement is also provided to the rock mass, which may increase its capacity to resist further degradation or loosening.Surface support has been routinely installed in most underground mines around the world for many years, yet the operators are still not always certain which type is best suited for deformable ground conditions. A number of factors need to be taken into consideration prior to selecting the type of surface support liner, such as its capacity, availability, practicality of installation, manual handling and loading conditions (static or dynamic) to ensure the system’s optimal performance in terms of safety and costs.This paper presents an overview of the surface support types currently used in underground mines in Australia. Shotcrete, weld mesh, high-tensile chainlink mesh, reinforced weld mesh and high energy absorption (HEA) mesh are discussed. A detailed description of each system is provided in terms of capacity, energy absorption, installation cycle and costs. The cost of each system has been normalised to the units of energy absorbed. The information presented in this paper can be used by underground operators as a reference guide when deciding on suitable surface support type for deformable ground conditions.CITATION:Louchnikov, V, Sandy, M P, Watson, O, Orunesu, M and Eremenko, V, 2014. An overview of surface rock support for deformable ground conditions, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 57–66 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

By B Vietnieks, N Widmer, L White, E Tata, J Natukunda, D C. Ilouga, J P. Tyler

The Republic of Uganda aims to exploit its’ significant, un-developed iron ore resources to supply the required raw material for developing its’ iron and steel industry across all the stages of the supply chain. Large prospects of iron ore exists in Uganda in the eastern (Tororo) regions and southwestern (Kisoro-Kabale) regions of the country. The Kisoro-Kabale iron ore projects covers mineralisation in hematitic banded iron formation (itabirite) in the north-eastern Congo-Tanzania Craton; covering ten Iron ore prospects. The prospects include Kamena, Karukara, Nyamiringa, Kyanyamuzinda, Rugando, Katagata, Rwengongo, Kijuguta, Kihumuro and Katuna. High-grade hematite ore prospects in south-western Uganda have known grades ranging from 55 per cent to 68 per cent iron ore content with an exploration target estimated at over 500 million tonne (Mt). Small scale production of iron ore from the south-western regions provide raw material to existing steelmaking and direct reduction iron ore plants located in the Jinja and Iganga districts of eastern Uganda. Large quantities of iron ore and other steelmaking raw material, however, are required to be imported into Uganda due to the limited exploration and development of their own iron ore mining operations. A joint collaboration between the European Union (EU), the Department of the Geological Survey and Mines (DGSM), Ugandan Ministry of Mines in partnership with Australian drilling and mining consultancies, ADT Africa and Kalem Group as a EU funded project was undertaken during November 2022 and September 2023. Exploration and evaluation of the ten iron ore prospects in south-western Uganda was undertaken through geological mapping, drilling, assaying, and technical studies with the view to attract investment for the development of Uganda iron ore mining and steelmaking industry. The collaboration developed mineral exploration policy, guidelines and standards, an iron ore exploration manual, a geological data management policy, and to support the sustainable development of iron ore mining in Uganda through building the capacity of local Ugandan geology and mining personnel through the transfer of knowledge and expertise from experienced iron ore experts. The quantification of these resources is an important first step in assessing their economic potential and attracting mining investors. This paper presents an overview of the investigation program and the preliminary results as an important first step in attracting mining investors to this exciting new iron ore province.

Sep 18, 2023

By D H. Laubscher

The in situ rock mass rating system û IRMR - leading to the mining rock mass rating system - MRMR - for jointed rock masses has been used (and abused) in mining operations around the world for the past 27 years. Despite the recent development of elaborate design procedures and computer-aided design packages, MRMR remains one of the most versatile and practical mine design systems available. It is important to realise that the rock mass classification system should not be replaced but rather complemented by more sophisticated and detailed design procedures. The classification system is not only the æcrudeÆ method used for initial assessment (as described in some geotechnical literature) but also in many respects a very effective and practical engineering tool. MRMR could, and should be used during the entire stage of mine life as an integral part of the design process. The objectives of this paper are to illustrate using practical case histories from the past decade, some of the pitfalls of the MRMR classification system, to clarify certain misconceptions in its application and update its mining application.

Jan 1, 2000

By M Jones

Legacy tailings storage facilities exist within operating mine sites across Australia. These tailings storage facilities are often viewed as rehabilitation liabilities but with considered assessment may prove to be a resource. Extraction of such a resource might add value to operations by providing cash flow during the development of new mines; providing supplementary mill feed for existing mines undergoing step changes in operations; and supporting mine closure activities. Hellyer Gold Mines is successfully extracting and reprocessing sub-aqueous material from legacy tailings storage facilities at their Hellyer operation in north-west Tasmania. The Hellyer tailings storage facilities contain poly-metallic material from the Hellyer and Fossey underground deposits dating back to the 1980s as well as material from tailings reprocessing activities by other operators of the Hellyer site. Hellyer Gold Mines is reclaiming sub-aqueous material using cutter-suction dredgers and reprocessing on-site. Hellyer is the only operation of its type in Australia and few such operations exist worldwide. Key learnings around the estimation of a resource for legacy tailings storage facilities have been acquired at Hellyer that can be applied to the assessment of other tailings storage facilities. The application of dredging as a mining method at Hellyer is delivered through collaboration with experts from outside the mining industry under the direction of a mining engineer. Key elements required for the planning and delivery of safe and efficient dredging inside tailings storage facilities have been identified at Hellyer and are presented to provide a road map to the development of other dredging operations.

Sep 1, 2024

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

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

Mar 22, 2022

By I Zh Bunin, V A. Chanturia, V G. Minenko, M V. Ryazantseva, A L. Samusev

A promising source for the extraction of rare metals and REEs in Russia is the eudialyte ores of the Lovozero deposit, which do not contain active uranium components. The eudialyte ore reserves of the Lovozero Massif are considered virtually unlimited and therefore have the potential to become a primary source of a number of rare and rare earth metals. The goal of this study was to comprehensively examine the effect of the parameters of high-power nanosecond electromagnetic pulses (HPEMP) and dielectric barrier discharge (DBD) on the leaching performance of eudialyte concentrate and the selective separation of zirconium and REEs from productive solutions. Using scanning electron microscopy and infrared spectroscopy, the mechanism behind the intensification of acidic dissolution of eudialyte as a result of pretreatment with energy impacts was described. During the HPEMP treatment, weakening and destruction of the eudialyte surface was observed, which at the substructural level is expressed in the deformation and local destruction of Si10O27, Si9MO30 resulting in formation of microcracks. During the DBD treatment, the formation of characteristic defects was observed in the form of imprints of dielectric breakdown microchannels and individual mineral fragments. Pretreatment of eudialyte concentrate using HPEMP made it possible to increase the recovery of zirconium into the pregnant solution of leaching by 3.4–4.3 per cent (from 86.6 per cent to 90.9 per cent) and by 4.1 per cent (from 86.6 per cent to 90.6 per cent) when using DBD. The increase in the total recovery of REEs was 1.2–1.8 per cent (from 87.7 per cent to 89.2 per cent). The effect of pH values, solution temperature, initial concentrations of valuable components on the successive recovery performance of zirconium and REEs from the pregnant solutions nitric from the acid leaching of eudialyte concentrate by chemical precipitation was examined. The possibility of selective separation of the zirconium product and rare earth elements with a zirconium recovery of 99.95 per cent and a REE recovery of 87.5 per cent was established. REE loss with the zirconium product was 8.0 per cent and 4.5 per cent with the spent pregnant solution.

Aug 24, 2022

By A Halim

"There is still debate about who should ultimately be responsible for the ventilation system in anunderground mine. The Queensland Coal Mining Safety and Health Regulation 2001, states that adedicated ventilation offi cer is the person, while Western Australian Mines Safety and InspectionRegulation 1995 states that it is the mine manager who is responsible; the ventilation offi cer actsas the managerÆs principal ventilation advisor. This paper outlines a comparison between bothapproaches."

Jun 1, 2012

By S Munn

Today, it can be said that the majority of mines utilise communications equipment in one form or another. Either for communications between staff making their day-to-day operations more efficient, or for emergency communications, as well as linking computer based mine management systems, and providing remote control over complex mobile and fixed machinery. With the advances in technology now available, we are moving into the next generation of mine communications equipment, using digital communications in the underground mine environment. It is a proven fact that an efficient underground mine communications system can help maximise production, by providing major gains in areas such as equipment and manpower utilisation, staff and vehicle tracking, reaction times to break downs and emergencies. In this paper we will describe some of the facilities that are currently available, as well as what will soon be available to mining and tunnelling companies around the world.

Jan 1, 1999

By Z Tong, M Gao, X Wang

In response to the need for improved magnetic separators for beneficiation of fine grained iron ores that have been finely ground to liberate the iron minerals from the gangue, a series of high efficiency wet drum permanent magnetic separators (T-GCT) has been developed by Maanshan Tiangong Technology Co Ltd. These magnetic separators have high efficiency for separating superfine strongly magnetic minerals and the ability to produce high-grade concentrates with high recovery. They are ideal replacements for conventional drum magnetic separators, especially for treating superfine particles.

Jan 1, 2009

By J Seccatore, G Sadao, M Cardu, G De Tomi, L Finoti, F Galvão, J Romero Huerta, A Rezende, J Bettencourt

In the mining industry, rock blasting can be considered as the first phase of comminution. The downstream phases of comminution are mechanical, and consist in consecutive stages of crushing and milling for grain size reduction. The total energy of mechanical comminution depends on grain size and on the resistance of the material to grindability. Usually, the first is quantified by the grain size distribution or one of its KPIs (such as the diameters X50 or X80), while the latter by the working index (WI), representing the amount of energy necessary to reduce the size of grains of a determined amount of material to the desired equivalent diameter (usually expressed in kilowatt hours per tonne – kWh/t). It is widely recognised that it is possible to manage the output of a blast in terms of grain size distribution varying specific charge (powder factor – PF) and charge distribution; specific algorithms such as the KUZ-RAM or the SWEBREC have been created to predict such output. It has also been demonstrated how higher PFs weaken the blasted material by creating micro-fractures that reduce its WI. This paper focuses on a related aspect: the influence of charge distribution on the specific comminution energy in crushing and milling. Small-scale blasts have been performed on 14 marble blocks with different PFs and charge distribution. For every PF, charges have been designed to simulate concentrated and distributed geometries. Concentrated charges simulate opencast blasts with large-diameter holes, with large burdens and spacings. Distributed charges simulate bench blasts with small-diameter holes and reduced burden and spacing. Three control blocks have been fragmented by mechanical means for comparison. For every sample the grain size distribution and the WI in ball mill has been determined. Results show the correlations between charge distributions and the specific energy of mechanical comminution in milling. Finally, the opportunity of adjusting charge diameters and distributions in opencast blasts to improve the output of the comminution circuits is discussed.CITATION:Seccatore, J, Romero Huerta, J, Sadao, G, Cardu, M, Galvão, F, Finoti, L, Rezende, A, Bettencourt, J and De Tomi, G, 2015. The influence of charge distribution on the grindability of the blasted material, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 749–754 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By R Winterberg

Concrete is a well established and reliable construction material for the permanent lining of tunnels, but shows some weak performance characteristics, which can be overcome by the addition of specialised fibre reinforcement. This paper addresses the particular performance design requirements of segmental linings, discussing the improvements of fi bres on concrete properties. Focus is made on the beneficial effects of fibre reinforcement on the cracking behaviour and the toughness performance, providing a safe and durable tunnel lining.Not only the mechanical performance of fibre reinforced concrete (FRC) for segmental linings, but also the durability of the linings has gained growing attention among the designers and consultants. Especially tunnel linings with exposure to media with corrosion potential, such as wastewater sewer tunnels or desalination plant outfall tunnels, have high requirements on their durability. The design of these structures must provide a comprehensive study of durability aspects. Fibre reinforcement can substantially improve the durability of concrete.Research has been carried out on the cracking behaviour of concrete. The beneficial effects of steel fibres on the cracking behaviour reduce the permeability by reducing the flow paths within the concrete. Crack bridging steel fibres create necking effects in bending cracks, leading to earlier closure of the cracks. Further, steel fibres create particular crack formations, which lead to a substantial reduction of the fl ow rates through separation cracks. The results also show that considerable cost savings can be achieved using FRC, as the thickness of the linings can be reduced.The durability design issues will be addressed and underlined by a case history on the Hobson Bay sewer tunnel in Auckland, New Zealand.

Mar 8, 2011

By S N. Donaldson, B L. Hollis, K Wynn, L Potts, M Evans

A real-time load-haul-dump (LHD) dispatch optimisation tool has been deployed at Panel Cave 1 and Panel Cave 2 at Newcrest’s Cadia Valley Operations. The tool, known as ORB, is the first known successful implementation of an optimisation-based, autonomous, real-time dispatch tool, custombuilt for underground mining operations. ORB can co-ordinate the optimal dispatch of LHD’s in a block cave to achieve a range of objectives while adhering to draw compliance and geotechnical constraints. It is an example of highly automated short-term interval control. This paper starts by outlining the pre-existing business planning process, detailing the simple logic that produced the daily draw order. Next, the motivations for a real-time dispatch tool are presented, drawing comparison to the limitations in existing planning processes and how these can be overcome through an optimisation-based, autonomous, real-time dispatch tool. Subsequently, the paper details the Ratio Bogging Draw Strategy, through which tonnes targets are expressed continuously on draw bells or draw points as a ratio of total cumulative cave draw. This signifies artificial planning boundaries are removed and that draw targets are linked within a cave; such that tonnes are unlocked by bogging other parts of the cave, instead of as a function of time. This creates incentive within the target mechanism for fixing and bogging struggling draw areas whilst allowing uncapped progress if all draw targets are progressing within compliance. Furthermore, the optimisation tool developed is outlined, including the data it uses and the objectives it optimises. Finally, detail on the improvements to operations the implementation of this tool has brought, and the business process change it has facilitated are presented using Newcrest’s Cadia Valley Operations as a case study.

Mar 15, 2021

By G Gilchrist, S C. Dominy, T Jashashvili, R C. A Minnitt

The grouping and segregation error is one of Gy’s seven errors that cannot be measured in any qualitative manner because of its transient and changing characteristics each time the sample is handled mechanically. Attempts to calculate the mean and variance of the segregation error is considered by some as ‘an exercise in futility’ that would not help us achieve representative sampling. This research is aimed at understanding the process of segregation of dense, finely divided and dilute particulate materials supported in a clean quartz substrate during intense agitation. Several mixtures of fine-grained materials including steel, tungsten carbide and gold grains were used in these experiments. Four hundred grains of each of the minerals and metals at a top size of 2 mm were mixed with approximately 600 g of finely ground quartz material (95 per cent passing 2000 microns) in a 500 ml plastic jar with a sealable lid. The mineral–?metal mixtures were analysed in three steps using microfocus X-ray computed tomography. Step one consisted of rolling the containers on a flat surface in an attempt to concentrate the mineral and metal grains in the core of the supporting substrate; this is a base case that can be reconstructed after each session of analysis. The second step involved gentle and vigorous shaking of the mixtures in order to segregate the denser minerals and metals from the supporting quartz substrate. In some cases, a third step involved splitting the sample through a riffle splitter. Three-?dimensional images of the surface of each grain, its volume and its X-, Y- and Z-coordinates, before and after intense agitation of the container, were interpreted from the reconstruction of the tomographic X-ray data. The spatial analysis of grains using cell declustering and 3D variography provided a useful means of characterising the distribution of the grains in space and the extent to which they had become segregated during the process of agitation. Spatial analysis indicates that in general, grouping and continuity of grains is weakly developed. The modelled nugget effect remains high for most tests, indicating that grains of similar size did not group together strongly. Agitation through rolling provided the best continuity, although not consistently in the long axis of the plastic jar. The nugget effect was consistently highest, and the range of continuity shortest in samples that had been split, indicating that the grouping and continuity were reduced through splitting the sample. Initial results indicate that very little segregation of the minerals and metals occurs in the quartz substrate. This is somewhat counter-intuitive, but suggests that the effects of agitation on mixtures of dense minerals and metals in substrates of lower density do not lead to excessive segregation. Differences in behaviour between dense materials in response to agitation are evident. Grains of different composition and shape did not group and segregate in a predictable manner in response to the agitation methods. Initial results indicate that the degree to which a material groups and segregates relates more to the characteristics of the denser material itself, rather than the agitation method employed.CITATION:Minnitt, R C A, Jashashvili, T, Gilchrist, G and Dominy, S C, 2017. Quantifying segregation of minerals and metals in particulate materials using computed X-ray tomography and variography, in Proceedings Eighth World Conference on Sampling and Blending , pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By A L. Stewart, M Baatar

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.The Middle Palaeozoic Gurvansaikhan Belt (Southern Mongolia) of the Central Asian Orogenic Belt is one of Central Asia’s most significant emerging porphyry copper provinces. The belt has become the focus of extensive exploration for porphyry copper-gold deposits over the last decade following the discovery of the giant Oyu Tolgoi porphyry copper-gold deposit. The Gurvansaikhan Belt is known to host porphyry deposits of Late Devonian (~370 Ma) and Early Carboniferous (~320 Ma) age. The characteristics of Early Carboniferous porphyry systems are poorly known compared to their older counterparts, despite their probable abundance and potential economic significance. Exploration within the Kharmagtai porphyry breccia complex has identified multiple cogenetic gold-copper-porphyry centres and late-stage mineralised magmatic-hydrothermal tourmaline breccias emplacement within a composite high-K calc-alkaline quartz monzodiorite intrusive complex. Early porphyry alteration and mineralisation at Kharmagtai are zoned around vertically attenuated early- and inter-mineral quartz monzodiorite dykes and stocks and comprises a complex sequence of calc-potassic, potassic and propylitic assemblages. Hematite dusting is a common alteration product that gives intrusions and the host rocks a distinctive pink-orange colour. Several of the systems have bornite-rich cores, where mineralisation is characterised by high gold grades (0.7 to >5 g/t Au) that zone outward to chalcopyrite-rich and then outer pyritic halos. Early stockwork mineralisation is overprinted by magmatic-hydrothermal tourmaline breccias. High-grade magmatic-hydrothermal tourmaline breccias form part of a major copper-gold mineralised breccia system with significant exploration potential. The Early Carboniferous porphyry copper-gold systems of the Gurvansaikhan Belt represent a substantial exploration challenge in an area of increasing exploration maturity. This paper summarises the characteristics of the Kharmagtai porphyry system that have helped to define the Early Carboniferous porphyry province of the Gurvansaikhan Belt and discusses implications for future exploration.CITATION:Stewart, A L and Baatar, M, 2015. The Kharmagtai porphyry breccia complex – characteristics of early Carboniferous porphyry mineralisation in the Gurvansaikhan Belt, Southern Mongolia, in Proceedings PACRIM 2015 Congress, pp 383–388 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Y Zhu, D J. Williams, M O’Neill, C Zhang, X Lei

A cover of inert material overlain by topsoil is required over compacted, seawater-neutralised red mud, a waste product from the refining of bauxite to produce alumina. The cover is to be revegetated, and it is necessary to demonstrate that the potential evapotranspirative-driven uptake of salts from the seawater-neutralised red mud will not impact the revegetation. An instrumented column was designed and constructed to test the evaporation-driven uptake of salts from compacted red mud into an overlying cover material with a thickness limited to 600 mm. The PVC column is 1.2 m high, with a 200 mm internal diameter. The column is instrumented with up to ten of each of moisture, suction, salinity and temperature sensors, together with a data logger, designed and manufactured at The University of Queensland (UQ) in Brisbane, Australia. The sensors were installed through the wall of the column at various depth intervals, with each set of sensors located at quarter points around the circumference of the column. Two pressure transducers were installed in the column to monitor the change of water level due to rainfall and evaporation. The column was filled with compacted red mud to a depth of 600 mm overlain by 600 mm of cover material, both sourced from the Queensland Alumina Limited (QAL) site in Gladstone, Queensland, Australia. The column is installed on a building roof at UQ, alongside a weather station, and will be subjected to the prevailing weather conditions for up to 1 year in the first instance, during which time the weather conditions and sensor responses will be continuously monitored. This paper reports on the instrumented column set-up and the early results obtained from the test.CITATION:Zhang, C, Williams, D J, Lei, X, Zhu, Y and O’Neill, M, 2018. Instrumented column testing of salt uptake from compacted red mud into a cover, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 220–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By X Li, J Wang, D Liu, Y Liu, K Hu

"Since the adoption of open-door policy 30 years ago, rapid economic growth has resulted in serious resource depletion and environmental destruction, especially in mining areas. As an urgent response to this situation, the central government and the Ministry of Land and Resources (MLR) have adjusted policies with concrete and realistic actions for halting this trend of non-sustainable mining activities in China. æGreen Mine CampaignÆ is one of the actions implemented. In 2010, MLR announced the æGreen Mine CampaignÆ, in which existing and new mines will be evaluated against the æGreen Mine Construction StandardsÆ and certified as æGreen MineÆ if complying with these standards. The standards cover five key aspects: the considerations of science-supported resource exploitation efficient resource utilisation standardised management environmental friendliness harmonious community relationship.Every year, MLR reviews ægreen minesÆ from all provinces. Thirty seven mines, including coal, metal, non-metal, gold, chemical industry and building materials mines, passed the review and were certified as green mines in 2010. In 2011, 187 out of 194 mines that participated in the review were certified as ægreen minesÆ. These mines are viewed as good examples of sustainable mining development in China.CITATION:Liu, Y, Hu, K, Li, X, Liu, Y, Liu, D and Wang, J, 2012. The green mine campaign and sustainable mining in China, in Proceedings Life-of-Mine 2012, pp 339-342 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

By B Reid

"Since the commencement of mining operations at the Cowal Gold Operations (CGO) in 2005, reverse circulation (RC) drilling has been the preferred method for grade control (GC) sample collection. This method was selected because it allowed:for multibench drilling (20 m hole depths for two benches of mining) to aid mine planning increased data density for comparison against the wide spaced ore reserve model angled drill holes to intersect perpendicular to the strike and dip of the shallow dipping mineralisation ability to take two metre sample intervals to enhance the understanding of the mineralisation’s short-scale variability and provide the ability to flitch mine.From June 2008 to December 2013, RC GC was performed using a UDR rotary cone splitter. The field duplicate data over the period displayed strong precision, with a correlation coefficient of 0.94 and an average relative per cent difference (RPD) of 21 per cent for gold. Up to 66.1 per cent of field duplicate data greater than 0.1 g/t fell within ±20 per cent RPD. This is within limits of industry best practice. The Mine to Mill reconciliations over the same period showed the estimated GC grade was 7.7 per cent lower than the calculated head grade (CHG).In December 2013, the Progradex sampling system (PGX) was introduced at CGO due to its advertised ability to capture 100 per cent of the drill cuttings for the complete sample interval, inclusive of fines. Analysis of field duplicate data indicates that since the introduction of the PGX, the sample precision has drifted. From January 2014 to February 2016, the correlation coefficient was 0.92 and up to 51.2 per cent of field duplicate data, greater than 0.1 g/t fell within the ±20 per cent RPD. Over the same 26 month period, the Mine to Mill reconciliation improved to one per cent lower than the CHG. Granulometric analysis of the RC samples collected from the PGX indicated the fines material(<212 µm) averaged up to 22 per cent of the samples mass and following assay determination, the fines material represented a weighted average of 31 per cent of the total gold content within the sample.This paper highlights the:importance of the complete capture of all drill cuttings during an RC drill programinfluence of fines material on the sample quality and accuracyimpact sampling of the fines material has on the Mine to Mill reconciliation performancechallenges experienced in commissioning a PGX system.Citation:Reid, B, 2016. A Fine Looking Sample - the Importance of Fines in Grade Control Sampling to Mine to Mill Reconciliation, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 28–38 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By S Q. Zhao, J H. Wei

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Xitieshan lead-zinc deposit is located in the north margin of the Qaidam Basin, Qinghai Province, China. It is one of the largest massive sulfide deposits in China and is supposed to be of the sedimentation-exhalation (SEDEX) type. Based on the main ore mineral and sulfur isotopic compositions in sulfides found in the wall rock, the S of the deposit is considered to originate from the mantle, but the fluid potentially mixed with sea water during the hydrothermal circulation exchange. The study of lead isotopes shows that the metallogenic material is characterised by the mixture of orogenic and upper crust sources. The lead isotopic signature of the wall rock is similar to that of the ore, which shows synsedimentary characteristics. According to the composition of the rubidium and strontium isotopic signature, the value of 87Sr/86Sr is lower than the average value of that in the crustal rock, which is larger than that of the mantle. Hence, the metallogenic materials of this deposit mainly originate from the crust, which is related to materials of volcanic rocks activation and migration of the deep hot circulating water. The process of the metallogenic fluid circulation shows continuous interaction with crustal material and lead to continuous enrichment of the ore forming fluids. From the study of the fluid inclusion microthermometry of the ore and the associated minerals combined with the C, H-O, Si isotopes, it is believed that the metallogenic fluid is mainly coming from the mantle or the deep magma chambers. The rising deep fluid then mixes with the sea water. The carbon dioxide escaping and mixing with sea water during the hydrothermal exhalation process leads to the rapid precipitation of the hydrothermal fluid to deposit metal. That is proposed as the principal formation mechanism of the Xitieshan deposit. Further studies are proposed, including obtaining geochronology data from this deposit.CITATION:Zhao, Z X, Wei, J H, Liang, S N and Zhao, S Q, 2015. Advances in research on metallogenic mechanisms for the Xitieshan sedimentation-exhalation lead-zinc deposit, Qinghai Province, China, in Proceedings PACRIM 2015 Congress, pp 487–494 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By N Maistry, C Carelse, A Singh

Banded Iron Formations or more commonly known as BIF are sedimentary rock formations with alternating silica-rich layers and iron-rich layers that are mainly composed of iron oxides (hematite and magnetite), iron-rich carbonates, and/or iron-rich silicates. Considering the depletion of highgrade iron ore reserves in South Africa, there is a need to maximise resource utilisation through the exploitation of low-grade/uneconomic resources particularly BIF material, which makes up more than 65 per cent of current reserves. Previous test work conducted by alternative BIF sources globally indicates the need for fines processing in order to produce a concentrate. South African BIF however is amenable to coarse and fines processing producing an on-grade product or blended feedstock. C-Type material within South Africa’s Northern Cape Province grading at approximately 33 per cent Fe was supplied for research purposes. Top size optimisation via gravity Heavy Liquid Separation (HLS) tests was conducted. The laboratory results being perfect separation (Ep=0) were modelled to predict pilot performance, the results of which were tested on a pilot scale for the finest size fraction (-1 mm). It was observed that a top size of -2 mm provided optimum results in terms of upgrade and recovery, with crushing finer not necessarily producing superior results. At a target grade of 60 per cent Fe, recoveries of 65.6 per cent were achieved on the laboratory scale, whilst recoveries of approximately 58 per cent were achieved on the pilot scale. Targeting higher upgrades of 63 per cent would inevitably result in lower recoveries of 57.2 per cent on a laboratory scale and approximately 54 per cent on a pilot scale. This is in line with grades and recoveries achieved globally for BIF material albeit at finer grind sizes.

Sep 18, 2023