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By T Walton, C Perring, M Pepper, G Gerber

The Yandicoogina Channel Iron Deposit (CID) is an accumulation of iron pisolites cemented by a goethite-rich matrix. The Yandicoogina CID’s are found in a palaeochannel that meanders within a broad structural basin of the Yandicoogina Syncline in Pilbara region of Western Australia. RTIO Yandicoogina Mine Geology team contributed to a number of strategies maximising the iron ore reserves mined by Rio Tinto. Two strategies are discussed: the replacement of the Batter-Berm final pit walls by contour dozing; and upgrading the lower grade material to crusher feed. 1. Contour dozing – traditional Batter-Berm pit final wall configuration left kilometre long wedges of ore sterilised around bench margins. Contour dozing final walls (ie dozing of ore down the ore-waste contact) as internally defined by RTIO Yandicoogina Mine Geology (Mine Geology), enabled recovery of additional crusher feed. 2. Upgrade of lower grade material – the lower ore domain (GVL) within the Yandicoogina orebody contains numerous clay pods. Contaminant Al2O3 inherent within clay pods can result in CID material outside of crusher feed grade specifications, causing it to be flagged as ‘internal waste’ in mining models and permanently lost to waste dumps. In 2011, after multiple tests, Mine Geology demonstrated that this material could be upgraded to crusher feed via wet processing. With the support of the RTIO Metallurgical Development team new grade specifications were defined. The resulting material has been used to supplement higher grade ore. While increasing the mining ore output, these ongoing value-adding strategies also promote more sustainable mining via better use of the non-renewable iron ore commodity. The initiatives extend mine life, reduce waste movement, improve strip ratio and increase productivity

Mar 22, 2022

By E Asakpo, S Chaffer, A Heath

Newmont has had continuous production at their Ahafo operations, Ghana, since 2006. In 2013, Ahafo initiated an efficiency programme to improve mill performance and reduce energy consumption. Following this assessment, a Turbo Pulp Lifter (TPLTM) was installed in the Ahafo SAG mill in April 2015 to replace the existing radial pulp lifters. Plant operational data showed delivery of a power saving of 10 per cent, an improvement in throughput of 3.3 per cent, with no loss of grind size. Pulp lifter life was also doubled from 11 to 22 months.However, during subsequent relines when the grates were removed it was found that one in four of the outer pulp lifters were wearing at a faster rate than the remainder. This was investigated by Discrete Element Method (DEM) modelling, which predicted some overtopping and internal recycle within the pulp lifter. Significantly, the model predicted that the recycled material would pass back down every fourth outer pulp lifter, matching the field observations. Subsequently, the DEM investigation was continued and became an R&D project to improve the TPL design. The results are summarised here, leading to the development of the next generation Spiral TPLTM.CITATION:Heath, A, Chaffer, S and Asakpo, E, 2018. The development of optimised pulp lifter design for the Ahafo SAG mill using discrete element method modelling, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 585–594 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By R Pozo, F Reyes

Codelco Chile is currently developing the El Teniente û New Mine Level Project (NMLP) in order to increase ore production by seeking to mine the ore deposit located under the current operational orebody. Reserves of 2000 million tonnes (Mt) have been quantified, which will be extracted as from the year 2017 by using the panel caving and progressive sinking method. Codelco and SKM Minmetal (SKM) jointly developed the project prefeasibility stage (PFS), closing these studies in March 2008. The first part of the project approach is to replace mine production currently feeding the Colon concentrator facilities with 137 000 tonnes per day (t/d), focusing attention on a production increase from the year 2026 up to 180 000 t/d. Project efforts have also been centred on maximising the contribution of new technologies for both construction and operational phases of the New Mine Level, together with selecting the best mine infrastructure to keep El Teniente operations going on for the next 50 years. Implicit in this is the inherent improvement of a variety of current Mina El Teniente process and management practices. The plan is to reduce actual mine operational risks and take advantage of new opportunities afforded by the project, which is in effect a greenfield project with respect to the implementation of fundamental changes in the labour and business environment. In addition, issues related to human resources, maintenance and management, materials handling, establishing centralised operations and accesses, automation and remote operations control and power efficiency could also be addressed. The project, beyond the New Mine Level exploitation, considers the mineÆs future potential, with a second deeper exploration in prospect named Deep Level. Finally, the project identifies features that would add value to the mine operations, in an initiative named æSpace for Future TechnologiesÆ. This will allow the eventual implementation of new electrical equipment and the application of mechanised technologies and other process improvements for the mine development.

Jan 1, 2008

By V Rajakumar, S Trang

Titanium has the potential to become the third wave of light metals used in high volume applications, following on from aluminium and magnesium. These light metals have functional attributes that can meet many of the goals needed for societyÆs transition to sustainable development. CSIRO has initiated a Light Metals Flagship to focus additional R&D efforts in support of the light metals industry. The vision of the Light Metal Flagship is for Australia to lead the Light Metals Age by reducing the costs and environmental impacts through innovative technologies for these metals. Life cycle principles will be used to identify novel technology pathways for metal production and product manufacture that are more energy efficient, less capital intensive and incorporating eco-efficient material flow chains.Under the auspices of the Light Metal Flagship, a Life Cycle Assessment (LCA) of titanium metal production was carried out with mineral sands mining of ilmenite as the starting point. Upgrading of the ilmenite to synthetic rutile by the Becher process and titanium metal production by the conventional Kroll process were the processing routes considered. Two alternative processes for titanium metal production, the FFC Cambridge process involving direct electrochemical deoxygenation of titanium dioxide, and a plasma process for producing titanium powder from titanium tetrachloride were also examined using LCA methodology and compared to the Kroll process. The environmental impacts included in the LCA were greenhouse gas emissions (Global Warming Potential, GWP) and acid rain gas emissions (Acidification Potential, AP). The Gross Energy Requirement (GER) of each process was also determined.These results for titanium, along with those from previous LCA studies by CSIRO on aluminium, magnesium, steel and stainless steel production, were used to show that despite the relatively large amounts of primary energy required for the production of these light metals, their special properties (eg corrosion resistance, strength and light weight) mean that these metals offer potential GER and GWP reductions compared to other competing materials in a number of applications, when viewed on a life cycle basis. Two applications considered in the paper are the lightweighting of motor vehicles and chemical plant equipment manufacture.

Jan 1, 2004

By J Player, P Evans, G Sweby

Achieving quick underground access after the completion of an open pit mine can be critical to maintaining project value and ensuring regular ore feed to the mill. This paper outlines the design and construction for two portals in an active open pit to commence underground development quickly whilst installing appropriate ground control to maintain long term access in an uncertain setting. Implementation of the portal designs was complicated by the change in underground design from hangingwall access to footwall access late in the life of the open pit due to preferable ground conditions. The portal locations did not have easy access for ground support installation integrated into the pit design due to the timing of the underground design changes. Practical implementation of the ground support systems subsequently became a key part of the project. Intact rock strength, rock mass characteristics, gradational weathering / alteration profile and structural information were modelled against pit displacement monitoring as the basis from which the portals were located and ground support schemes designed. Conditions around one of the portals necessitated numerical modelling to estimate the appropriate level of ground control for long term stability. The design was completed whilst the open pit was actively on-going and the portal areas not entirely exposed. The rock mass assessment and analysis for the two portals indicated different ground support scheme capacities would be required. The expected level of control for one of the portals also necessitated the use of monitoring with extensometers and load cells to ensure the rock mass response and ground support scheme performed as planned. Construction of the portals demonstrates the benefit of a considered design process, a plan which allows practical installation of ground support schemes where access is limited, the benefit of ongoing monitoring to ensure performance remains within design limits and the challenges involved working within an active pit with limited floor space.

Mar 15, 2021

By J Carswell, K McTyer

The Pajingo gold operation in Queensland is approximately 50 kilometres south of Charters Towers and 134km south-west of Townsville. The resource was discovered in 1983 and first open pit gold production began in 1986. The mine traditionally employed a bottom-up sequence – a combination of modified and traditional Avoca methods with run-of-mine waste backfill. This practice caused many high-grade crown pillars to be left in place, yet accessible. In recent years, these crown pillars have been extracted by injection grouting of rockfill. This process facilitated blind up-hole open stoping. To date, thirteen separate injection campaigns have been completed, of which ten were deemed successful. In general, the two key technical difficulties in this mining technique are: maintaining a consistent high-quality ground consolidation of the rock fill material; and controlling the drill and blast practices during stoping. Here, effective drill-and-blast control was found to be essential to achieve the dual aims of 100% extraction, and maximum sill pillar stability to minimise dilution. During stoping, the technical performance of the consolidated rock-fill was recorded; both to verify the design, and to identify operational improvements. The results showed that Pajingo has realised both reduced production down-time through use of early strength gain grout, and more rapid and thorough grout consolidation through changes to the emplacement method. The optimisation of consolidated rock fill has led to several quantifiable benefits to the mine, including: profitable extraction of previously sterilised crown pillars resulting in both increased ore reserves and production profile; improvements to the stability of grouted stope crowns, thereby reducing safety and production related; risks associated with open up-hole stopes; reduction in cost and time constraints, with respect to the grouting of loose fill; and reduction in grout curing time – from 14 days to 8 days – thereby minimising production down-time. This paper is a case study of the evolution and optimisation of the up-hole open stoping mining method at Pajingo. The challenges and successes are discussed in terms of their key mining outcomes. CITATION:McTyer, K and Carswell, J, 2018. Evolution of rock fill consolidation at Pajingo Gold Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 66–77 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By M D. Griffith

Oct 12, 2022

By Y Wu, F-J Ping

Today, coal production accounts for about 65 per cent of the nationÆs gross energy in China. By the year 2010, the output of coal is planned to increase to 1.65 billion tonnes and by the year 2020 to 1.9 - 2.0 billion tonnes. To meet these energy needs the Chinese coal industry is developing underground coal production on a massive scale. The new drive introduced by using direct torque control (DTC) is now proven technology for mine shaft hoisting. The drive offers unequalled speed and torque control performance as well as a low impact on the supply network by controlling the power factor to unity with a minimum of harmonics distortion.

Jan 1, 2005

By J Foo, T Kleinschmidt, B Reynolds, K Kennewell

The consideration of complex supply chains often highlights multiple system bottlenecks that are localised and dynamic – they shift depending on what variability last influenced the system. Using the understanding of a dynamic system model, synergies between items that tackle localised bottlenecks can be understood to generate a suite of solutions. These can be simple solutions, such as a couple of new conveyors placed in series, or more complex ones, including buffer dynamics (capacity, location, behaviour, etc).Each solution in the suite will have an associated uplift in system performance and an associated cost of implementation. Dynamic simulations can address each situation in turn and estimate the projected improvement it would offer. However, these solutions will have different benefits when implemented together, and each solution will give different uplift depending on what other solutions have already been assumed. If the number of solutions is numerous, traditional dynamic simulation analysis becomes the bottleneck, limiting options analysis to the processing power available.This paper will illustrate the use of a new technique applied as part of a capital growth optimisation project with a major iron ore producer. Metamodelling is the creation of a model of a model; in this case study, the focus is on developing a response surface representing the suite of solutions. This can be achieved through a combination of dynamic modelling and an appropriate mathematical process called design of experiments. The result is an approximation surface of the outcomes of the dynamic model, encapsulating interactions between key elements of the value chain.This modelling approach provides a number of advantages compared to traditional dynamic modelling approaches, including but not limited to:early and rapid evaluation of a large range of potential solutionsaccommodation of multiple initial states of the value chainoptimisation of the overall suite of upgrades (down to route-level upgrades) based on business objectiveseasy re-evaluation of outcomes when key inputs such as costs change.CITATION:Kleinschmidt, T, Foo, J, Reynolds, B and Kennewell, K, 2015. Case study of iron ore value chain optimisation, in Proceedings Iron Ore 2015, pp 605–612 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By S Farrokhpay, C Akop

Copper-gold-pyrite ore types with an elevated pyrite head grade utilise a sequential flotation circuit to recover initially a copper-gold concentrate with a pyrite-gold concentrate being produced from the tailing of the initial circuit.A simpler flotation circuit with lower operating and capital costs for treatment of such copper-gold-pyrite ores with an elevated pyrite head assay was sought in the described work. After characterising the ore, the objective was to apply bulk rougher flotation of both the copper minerals and pyrite for the copper-gold-pyrite ore at natural pH. Hence, no lime or other pyrite depressants were required in bulk roughing. The bulk rougher concentrate was upgraded in a cleaner circuit to reject non-sulfide gangue and then the resulting sulfide concentrate was separated by depressing the pyrite to produce two products (copper and pyrite concentrates, both having significant gold assays). A standard test with a sequential circuit was applied to the same ore for comparison.The chalcopyrite and pyrite losses in the tailing from the rougher circuit were the same for both bulk and sequential roughing (less than six per cent). In cleaning (bulk circuit), the effective pH for pyrite depression was 11.8–11.9; copper recovery was 70–75 per cent (grade of 15–20 per cent copper) and the sulfur recovery (pyrite product) was 80–85 per cent (grade of 34–36 per cent sulfur).These results approached those for the sequential circuit where copper recovery was 80–85 per cent (grade of 15–20 per cent copper) and the sulfur recovery (pyrite product) was 83 per cent (grade of 38 per cent sulfur).The observed effects of feed sizing on the liberation of minerals in the rougher feed are discussed. Options for improving the bulk circuit results are also considered. Importantly, the implications of various aspects of these findings for the bulk circuit are discussed with an industrial focus.CITATION:Akop, C, Farrokhpay, S and Johnson, N W, 2014. An alternative circuit for chalcopyrite-pyrite ores with elevated pyrite content in Cu-Au ore treatment, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 407–416 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By T G. Vizcarra, B Wong

Optimisation projects are regularly undertaken without knowing the root cause of an issue. It is all well and good to trial a multitude of flotation reagents, change the operating characteristics of your flotation cells, or add more media into your ball mills, but time and again, root cause analysis traces issues back to the performance of hydrocyclones. In JKTech's experience, hydrocyclones are poorly operated and maintained (in both primary grinding and regrind circuits), exacerbating issues that many operations commonly experience.Recent case studies are presented where JKTech has been engaged to improve the process only to discover that the hydrocyclones were the main issue. At one operation it was found that the hydrocyclone feed density gauge was reading significantly lower to the actual density. Following re-calibration of the gauge, and with further improvement of cyclone operational and design parameters using JKSimMet, a significantly sharper efficiency curve was achieved. This resulted in improvements to downstream recoveries while alleviating pumping capacities that were previously constrained by fines and water caught up in recirculating loads.Several other case studies are presented which may seem to be relatively basic, but many basics seem to be getting lost in the day-to-day responsibilities of the modern plant metallurgist. Simple fixes to hydrocyclones can result in significant production increases, but more focus is needed in monitoring these to sustain the benefits.CITATION:Wong, B and Vizcarra, T G, 2018. What category cyclone is devastating your plant?, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 665–673 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By S Pradhan, A Kuras, R Mahajan

This paper describes the design of the precast concrete segmental lining for the 13.1 m internal diameter and 450 mm thick, 2.4 km long mainline tunnels for the Waterview Connection project in Auckland for the New Zealand Transport Agency.The design and detailing of this segmental lining presented some noteworthy challenges, including an alignment that has sections of low cover in soft ground. Key points of interest are that this precast segmental lining is the largest to ever include steel fibres as the primary method of reinforcement and the lining includes cams on circumferential joints to control ring deformation.The paper describes some of the key design decisions that were made in a collaborative manner with the construction team, tunnel boring machine manufacturer, segment manufacturer and the designers.CITATION:Mahajan, R, Kuras, A and Pradhan, S, 2014. Design of segmental lining for Waterview Project, Auckland, New?Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 289–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By C F. Stokes

The Trident Gold Deposit has been successfully developed by Alacer Gold (formerly Avoca Resources Limited) into a 1.3 Mt/a operation in the space of four years from discovery to first gold pour (2008). The current in situ Resource for Trident is estimated to be 5 900 000 t @ 5.0 g/t for 940 000 ounces at a cut-off of 1 g/t or 2 g/t depending on ore style. Production to date (Alacer and previous owners) is in excess of 500 000 ounces. The deposit lies towards the southern end of the Norseman-Wiluna Greenstone Belt in the Archaean Yilgarn Craton, where it is centred on the historical Higginsville Mining Centre, midway between the world class gold centres of St Ives (+15 Moz) and Norseman (+6.5 Moz). Trident is hosted primarily within a thick, weakly differentiated gabbro with subordinate mafic and ultramafic lithologies and comprises a series of north-northeast trending, shallowly north plunging ore zones. The deposit comprises two main mineralisation styles; large wallrock-hosted ore-zones comprising sigmoidal quartz tensional vein arrays and associated metasomatic wall rock alteration (Eastern Zone, Western Zone and Apollo) hosted exclusively within the gabbro; and thin, lode-style, nuggety laminated quartz veins (Athena and Artemis) that formed primarily at sheared lithological contacts between the various mafic and ultramafic lithologies. The initial interpretation of the Trident Deposit was based on steeply-dipping structures controlling the zones of mineralisation, with much of the targeting and drill-testing aimed at this style of orebody. Subsequent exposure of the orebodies has identified a series of shallow-east dipping mineralised systems (interpreted to be large reverse shears) that at their intersection with the steep-dipping structures cause significant gold enrichment. It is postulated that both orientations are primary fluid pathways with the intersection between the two resulting in zones with significantly high concentrations of gold mineralisation (in excess of 300 000 ounces). This new understanding on ore controls at Trident has identified that the thin lode-style shear-hosted laminated veins are continuous for over 1700 m along strike as they step en echelon down-plunge. In addition, a repetition and periodicity to the intersection between these steep dipping lode-style systems and the shallow-dipping mineralised zones (estimated to be 700 - 900 m down-plunge) has been identified which has considerably increased the down-plunge potential of the Trident Deposit.

Aug 22, 2011

By L Kempenaers, T van der Maten, U König, M G. C Zoontjes

Improving liquid blending operations in production plants is of paramount importance in many industries like mining, oils, petrochemicals and food. For accurate blending of different types of process streams, like homogeneous, heterogeneous, cold or hot streams, it is essential that the composition can be accurately monitored in real time. Advances in energy dispersive X-ray fluorescence (EDXRF) technology offers the possibility to apply XRF for online elemental analysis. In this paper we discuss an online EDXRF analyser for accurate blending control in many industries.EDXRF has the advantage that multiple elements can be measured simultaneously over a wide concentration range of wt per cent down to a few mg/kg, for elements between sodium (Na) and americium (Am) in the periodic table. To reach the desired accuracy and precision in an online XRF analyser, it is important to bring a representative and homogeneous sample of the process flow into the optical path of the analyser. The combination of a laminar flow cell design and advanced EDXRF technology leads to low detection limits and high performance. The obtained precision and accuracy allows for much tighter process control. In this paper we present two examples of industrial applications.CITATION:Zoontjes, M G C, van der Maten, T, Kempenaers, L and König, U, 2017. Online X-ray fluorescence spectrometer for accurate monitoring and improving blending sharpness in liquid production processes, in Proceedings Eighth World Conference on Sampling and Blending , pp 235–238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By J H. Zietsman

The transition to more sustainable metal production is receiving much attention at present, and the iron and steel industry is at the centre of the conversation. New, more environmentally friendly production technologies, such as direct reduced iron (DRI) smelting furnaces, need to be developed in a short period of time. This necessitates increased use of computational modelling that incorporates more accurate material descriptions. The combination of large-scale multiphysics models of high-temperature processes with CALPHAD material descriptions leads to infeasible computation times. This can be resolved with the previously reported RapidThermo framework, which has been demonstrated to make equilibrium calculations orders of magnitude faster, within controllable limits of accuracy. In this paper, we explain how further material properties, which are important to modelling hightemperature reactors, can be added to the RapidThermo framework. This can improve the accuracy and usefulness of process and multiphysics models in the development of new technologies, which can significantly accelerate development cycles.

Aug 21, 2024

By J P. Sykes, T C. McCuaig, J E. Vann

Resources added to the global metal inventory through exploration over the past 15 years have been generally of poor quality (declining grades, recoveries and lack of acceptable financial return). Similarly, companies opting for an acquisitions-based strategy have had to pick from a group of poorer quality resources left from previous exploration booms, and will struggle to deliver this metal to market economically. Increasing difficulty in obtaining sufficient social and community acceptance of mining projects and potentially an energy-constrained future may exacerbate this problem, redefining what is considered ‘ore’. There will need to be more focus on deposit quality, defined as sustainable margin in the future business environment.Traditionally there has been a lack of translation of ‘mineralisation quality’ back to mineral project design and mineral exploration. This disconnect is due to two main factors: the first is technical – inherent deposit variability; and the second is organisational and socio-psychological –the mindset of explorers and project managers themselves.There are four elements to value realisation for a mineral deposit: (1) social licence to operate; (2) geological factors (depth, geometry, water and geotechnical, and geometallurgy – influenced by texture, mineralogy, chemistry and grades); (3) financial engineering (capex, opex, future commodity prices, future energy prices), and (4) operating factors (production rate, recovery, energy consumption). These elements are strongly interdependent, and geology underpins and drives linkages between them. A quality deposit addresses all of these elements and thus can be developed in a time frame that allows acceptable returns to the owners of the invested capital.Geological drivers of the above elements can be measured and mapped throughout a deposit. Moreover, when viewed in the context of mineral systems, a predictive understanding of the common causative processes of quality (despite deposit-scale variability) is emerging, and with it the ability to target quality of mineralisation, not just quantity of mineralisation.The second factor is a ‘heuristic software problem’. Current lines of education (and consequently organisational and professional structures) are discipline-based, producing ‘silos’ that do not speak each other’s language and work with different ‘mental models’. People who effectively recognise systemic links between these silos are called ‘boundary spanners’, of which we propose two distinct types: outside-insiders and inside-outsiders. Outside-insiders are people who are within a community, but recognise advances in outside fields and effectively integrate them into the community. Inside-outsiders start outside of a community, and successfully bring new ideas into it. Common traits in boundary spanners are: they seek exposure to (and embrace) key ideas that are outside of the framework of their own specialisation; they have high mental processing ability (MPA) – the ability to connect systems that are currently not perceived to be connected; and they introduce ideas from outside a field into a new context in a way that re-frames the field.The challenge is to identify and nurture potential boundary spanners that can build critical links, in particular between the (largely geoscientific) mineral exploration mindset and the (largely non-geoscientific) project development mindset. Critical linkages to be built are between mineral system science, targeting science, and whole of value chain modelling.CITATION:McCuaig, T C, Vann, J E and Sykes, J P, 2014. Mines versus mineralisation – deposit quality, mineral exploration strategy and the role of ‘boundary spanners’, in Proceedings Ninth International Mining Geology Conference 2014 , pp 33–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Lawson F

Chrome chemicals are commercially produced by the alkali roasting of the chrome-bearing ore chromite with sodium carbonate. In order to ascertain the influence on the extent of reaction of the replacement of Mg(II) for Fe(II) in the chromite spinel structure and the presence of acidic oxides in the gangue material, a series of roasting experiments was conducted using chromite materials from a number of different locations. The roast feeds and products were chemically analysed and the major compounds identified using X-ray diffraction and scanning electron microscope techniques.Mg(II) replacement for Fe(II) in the chromite structure does not appear to restrict the amount of "available" chromium for reaction.Under the test conditions, namely an atmosphere of pure oxygen, finely ground chrome-bearing material, a roast temperature of 950°C and the stoichiometric amount of sodium carbonate to react with the chromite, the yield of water-soluble sodium chromate was able to be expressed as %yield = 104.5 -1.58 × %AI2O3 - 2.23 × %SiO2 for chromite samples containing alumina in the range 7.8 to 27.8 per cent and silica in the range 2.9 to 7.4 per cent.

Jan 1, 1984

By M Chaudhari, G Manekar, D Shome

MOIL Limited is operating 7 underground and 3 opencast mines in central India and producing annually more than 1.2 million tonnes of various grades of manganese ore. The underground mines are operating at shallow - 90 m at Munsar mine to moderate - 353 m at Balaghat mine below the surface with horizontal cut and fill (HCF) or its variant method of stoping with post filling by hydraulic sand stowing. The Munsar mine is being worked underground since 1903. The opencast mining is presently stopped. The ore body below the opencast quarry is geological continuity of the area excavated in past by opencast method of mining. The underground mining is done through the adit in three levels i.e. 270’L, 220’L, 170’L and by incline in western part of the property at 70’L. The horizontal drift development has been developed in the manganese ore body with sill drive of 5 m above the sill pillar in lower level at 70’L and barrier pillar of 5 m thickness is left for protection of upper level at 170’L. Valuable mineral has been locked in sill pillar and therefore rock mechanics investigations have been carried out. On the basis of study now the drift development has been carried out in footwall rock at 70’L, (-) 30’L and below levels and it has improved the mineable manganese ore by about 20%. In this modified HCF stope design, an alternative fill material in place of sand, which has been developed in house by use of overburden (OB) material after treatment, has been used for hydraulic stowing. The experimental trials find out that the alternative fill material of OB is more compact and forming a non expansion floor for the men and machines in the stope. This will certainly help in the introduction of mobile underground mining equipment for drilling in the stopes and mechanical mucking, transportation and loading of the ROM. The paper presents rock mechanics investigations and future use of alternative fill material of OB for better safety and productivity at Munsar Mine of MOIL. CITATION:Manekar, G, Shome, D and Chaudhari, M, 2018. Modified ground support with alternative fill material for ground control at Munsar underground manganese mine of MOIL Limited, India, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 58–65 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By D R. Seaman, B Adamson, P Sharman, M McMahon

"The Telfer processing plant commissioned its pyrite regrind and flotation circuit in August 2012. The circuit was designed to regrind pyrite concentrate to a p80 of <30µm then float a gold and copper rich concentrate before tails from the flotation circuit fed the carbon-in-leach (CIL) circuit downstream. Expected benefits were: improved CIL performance that would result from the finer grind and a reduction in cyanide soluble copper to the CIL circuit, as well as a small increase in overall flotation circuit recovery. While the benefits of a finer grind were soon realised, recovery in the post-regrind flotation circuit (named the ‘pyrite recleaner circuit’) was consistently and significantly lower than that expected based on laboratory test work. Selectivity in the pyrite recleaner circuit was virtually nil and copper reporting to the CIL circuit did not change as a result of the pyrite recleaner circuit operation.A pulp chemistry survey of the plant and comparison with the lab showed that the dissolved oxygen (DO) demand in the plant was much higher than that in the lab. Lab flotation tests conducted using nitrogen gas instead of air resulted in recoveries similar to those from the plant. It was identified that the freshly ground pyrite surfaces exiting the regrind mill were consuming oxygen in the slurry and there was insufficient oxygen available for collector adsorption and pyrite depression to occur. Test work, using a pilot regrind mill, showed that a reduction in grind size resulted in an increase in DO demand.A range of oxidising agents were tested in the laboratory and using a pilot flotation rig set-up in the plant. Oxygen was found to be the most reliable and effective agent and options for increasing oxygen delivery to the plant were explored. Scale-up from the lab oxygen requirement to the plant is difficult and efforts to implement a permanent solution for meeting the DO demand in the plant are ongoing.Citation:McMahon, M, Seaman, D R, Sharman, P, Adamson, B and Seaman, B A, 2016. Optimising the Telfer Pyrite Regrind Circuit - Effect of Dissolved Oxygen Demand, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 51–58 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By R Dimitrakopoulos

Optimisation and mathematical formulations for open pit design and long-term production scheduling have been available since the 1960s. There are two main concerns in the application of existing mixed integer programming (MIP) models in open pit mines: a. the feasibility of generating both optimal solutions and practically mineable scheduling patterns and b. the inability to deal with in situ variability in orebodies and account for uncertainty. In dealing with these issues, a general open pit production scheduling method for multi-element deposits is presented and subsequently used to optimise the long-term production schedule in a nickel laterite deposit. The application shows the weaknesses of MIP formulations in terms of generating optimal solutions as well as practically feasible mining patterns. The application of the same formulation in the presence of in situ orebody variability and uncertainty uncovers a major reason for deviations of scheduled production from actual production, and outlines additional limits of traditional optimisation formulations as well as future needs.

Jan 1, 2003