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By D Teyhan, J Kirsch

Traditionally, most Australian iron ore mining operations have been surface-based. Processing plants were designed to handle dry ores. In recent years mining operations in the Pilbara have progressively moved below the water table exposing wet, sticky ores which have caused lost efficiency in screening operations as particles tend to agglomerate and adhere, blinding screening media. Miners and vibrating screen manufacturers have experimented with a shift from linear motion to elliptical motion screens. Elliptical motion conveys and lifts particles. Effective on flat deck (horizontal and inclined) or sloping decks it can be configured to provide a controlled transport rate, applying pressure in all directions to maximise screening efficiency. In practice, elliptical motion screens have proven to be effective in dislodging sticky particles from screening media, reducing blinding rates and improving screen efficiency. Moisture and clay content change during the life of a mine. These changes are sometimes the effect of seasonal rainfall, in other cases due to increased groundwater and clay content as mining operations go deeper. To compensate for such changes and optimise screen efficiency, changing the ‘shape’ of elliptical screen motion is required. This has traditionally required shutting down processing plants and making mechanical screen adjustments. Plant downtime is costly and machine adjustment has been a ‘trial and error’ practice. This paper will explore the results of a field trial that is currently underway in Brazil of a next generation elliptical motion screen design that allows operators to make changes to exciter rotational direction, speed and screen stroke angle, through electronic drive phase control. The machine’s electronic drive system synchronisation is enhanced for stability with a unique mechanical timing system. Operating at up to 6 g, screen adjustments can be made on the fly without stopping production. Early trial results are showing up to 50 per cent improvement in screen efficiency compared with traditional elliptical motion machines under certain feed conditions.

Nov 8, 2021

By J Q. Cooper

The New Zealand rail authority, Kiwi Rail and Auckland Regional Transport Authority (ARTA), are jointly planning a new mainline rail link between Auckland’s downtown Britomart Station and the existing Western Line at Mt Eden. In 2009, APB&B, a consortia of Aecom, Beca, Parsons Brinkerhoff and Hassell Architects where commissioned to develop the conceptual design, Assessment of Environmental Effects (AEE) and business case for the new 3 km rail line towards preparing a Notice of Requirement to protect the route through Auckland’s central business district.This paper describes the engineering challenges in the development of the conceptual design for the three proposed underground stations, the running tunnels and connections to the existing network. Feasible alignment and station location options were developed and evaluated using multi-criteria analysis based on key client functional requirements, constraint mapping and environmental impacts. The resulting preferred scheme was then developed to a conceptual design suffi cient for assessment of environmental effects, risks, and the development of a robust construction methodology to allow high level capital cost estimates.The paper describes some of the major challenges overcome to develop the concept, including steep gradients, narrow street envelopes with existing buildings and structures, the need for large platform spaces with low ECBF rock cover and complex connections at Britomart and the main line near Mt Eden.The development of the conceptual design of the underground stations in particular demonstrates the need for a holistic value engineering approach to satisfying the architectural and functional requirements, in a highly constrained dense urban environment and at lowest practical cost. The construction methodology was a key input to the conceptual design development throughout.The conceptual design will be used as the fundamental basis for the development of the AEE and business case for the project in the future.

Mar 8, 2011

By J Stipcevich, N Patel, J Faithful5, S Narendranathan, L Tatnell4

ENGIE, the current owner and operator of the Hazelwood Open Cut coalmine, are in the process of rehabilitating the mine site in preparation for mine closure. Bucket wheel excavators (dredgers) used during coal mining operations are in the process of being demolished, which involves the controlled felling of dredger components using explosives. With the mine located in close proximity to the Morwell township and other critical public infrastructure, it is crucial that the use of explosives and the possible implications for mine stability is well understood. The felling of Large Mining Equipment (LME) will apply an impact load immediately to the underlying coal benches with the adjacent coal batters potentially at risk also of adverse slope stability impacts. This paper presents the 3D stability modelling methods employed to successfully assess the potentially adverse stability implications associated with LME collapse.

Jun 21, 2022

Continuous, steady-state laboratory flotation tests showed that the recovery of cha1copyrite from a naturally occurring ore, under conditions closely resembling those of plant practice, could be expressed in terms of a first order rate equation.Tests on full-scale plant flotation cells, using impulse tracers, indicated ideal mixing of the pulp in the cells.It was demonstrated that values of first order flotation rate constants can onlv be obtained from conventional methods of analysis in special cases.Analysis of a plant sampling campaign by the author supported a first order kinetic equation for two mineral species, and for the individual size fractions of one of these.The effect of stage-addition of reagents is interpreted in kinetic terms.

Jan 1, 1966

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 A Whaanga, W Vigor-Brown

IGO Ltd’s (IGO’s) Nova-Bollinger Deposit (Nova-Bollinger) is a magmatic nickel-copper-cobalt (NiCu-Co) sulfide deposit found 160 km east-north-east of the town of Norseman in Western Australia (WA). The deposit is hosted by the Mesoproterozoic rocks of the Fraser Zone, which is part of the Albany Fraser Orogen (AFO). Since mining commenced in 2016, IGO’s Nova Operation (Nova) has mined and processed to 31 December 2020, 5.63 Mt of ore grading 2.04 per cent Ni, 0.86 per cent Cu and 0.07 per cent Co. Nova’s mine geology team (MGT) has used commercially available implicit modelling (IM) and general-purpose resource modelling (RM) industry software systems, to prepare the 31 December 2020 (CY20) update of Nova-Bollinger’s JORC Code reportable Mineral Resource estimate (MRE). This CY20 MRE update was predominantly based on ~386 km of diamond core drilling, with the drill holes having a nominal grid spacing of 12.5 by 12.5 m throughout the mineralised zones of the deposit. Using IM tools, Nova’s MGT interpreted and modelled 22 separate domains from the drill hole logging, assaying results, and the MGT’s underground mapping. These IM closed volumes were then used to control the estimation of MRE variables into conventional industry digital block models using RM and other ancillary software systems. During 2021, a commercial machine learning (ML) software was trialled by Nova’s MGT for preparing block models of Nova-Bollinger’s MRE domains. The motivation for the trial was that the ML process could expedite modelling through the direct creation of a domain coded block model from the drill hole logging. Compared to the industry standard approaches of wireframing or IM, where the modeller usually makes many subjective choices to produce the domain model, ML offers a more objective ‘hands-off’ process for determining the connectivity of domains defined in drill holes. Additionally, the ML process provides a quantitative confidence metric associated with its output that may have utility in mine production and resource classification. In this paper, the results of the Nova-Bollinger ML modelling trial are compared to the MGT’s current workflow for MRE work. The MGT’s conclusions as to the advantages and disadvantages of the IM and ML methods for preparation of MRE domains are discussed. The ML software was also tested as a method of rapidly interpreting geology outside the principal zones of MRE interest. These testing results are also presented in this paper.

Mar 22, 2022

By C Tonkin, S D. Howell, P V. Johnson, J Moriarty, P W. Duck

This paper presents the scientific framework underpinning the resource valuation and optimisation model (RVOM). The RVOM is a partial differential equation based real options software package, which helps mine owners optimally plan their operations, understand their project risks, and make defensible valuations. This is achieved in the presence of both financial and physical uncertainty, as well as processing capacity constraints. The RVOM can be applied to any multi-ore mine, open pit or otherwise, where the block-order of extraction has already been planned using existing software tools such as the Gemcom WhittleÖ strategic mine planning package. The RVOM can also take account of multiple commodities within a single mine, and multiple forms of price behaviour. The three key outputs from the RVOM are: valuation, optimal decision and probability of decision. A decision takes account of upfront costs, and can include an unlimited number of transitions between: normal operation, expanded operation, care and maintenance and abandonment (and variants thereof). The RVOM then employs stochastic process theory to determine the probability of reaching these decisions. This gives the mine operators clear indications as to where their risks lie, aiding their mine planning. A clear example of the RVOMs usage to a case-study gold mine is presented, demonstrating its broad applicability, the added value it can create and how users can easily make use of the RVOMÆs state-of-the-art algorithmic engine.

Sep 26, 2011

By S H. Burgmans, B Anderson

This paper aims to define the specific challenges relating to dredging fine tailings from an above ground storage facility for transferral to a mined-out pit. In addition, it compares dredging and mining perspectives on dredging of fine tailings.

Jul 1, 2021

By R M. Stephenson

Large diameter raise boring is a common raise excavation method in the Australian mining industry. Geotechnical investigations were conducted on several large diameter raise bore projects at Gwalia Mine to assess the potential for instability and potential back-reaming problems. A thorough geotechnical analysis and subsequent back-analysis was conducted on a vent raise excavated at 5.5 m diameter and 810 m length.The geotechnical investigation for the vent raise included collection of data from an acoustic televiewer survey that was conducted on the pilot hole. The survey results provided structural data and an insight into the effects of stress on the pilot hole. Structural analysis was conducted using a combination of information obtained from the acoustic televiewer survey and geotechnical logs of the diamond drill core drilled close to the site.Further information was collected from drillers’ plods from pilot hole drilling and back-reaming to conduct a back-analysis of the completed shaft, and this was compared with the structural analysis.The key finding from this review was that the acoustic televiewer survey of the pilot hole accurately identified locations with blocky conditions. This is an important supplement to the information available from the main geotechnical investigation hole, as this was offset from the shaft location over most of its path.CITATION:Stephenson, R M and Sandy, M P, 2014. Structural analysis of acoustic televiewer logs for large diameter raise bored shafts, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 89–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By M Salu, G J. Kay

"As underground mines increasingly face the challenge of maximising production without losingfocus on safety excellence, the ability to predict the eff ectiveness of mine seals and stoppings andthe identifi cation of defects plays an increasingly important role in mine ventilation management.While technologies for sample testing installed seals provides signifi cant assurance, the difficulty of conducting tests in operational environments, combined with the production impact of destructive testing procedures, has led to the development of a new method for non-destructively testing ventilation control devices (VCDs). This paper addresses the challenges of in situ testing and reviews the approaches previously employed to verify the quality of VCD installations. It then describes a new testing methodology jointly developed by Whitfield Minerals PTY Ltd and Parsons Brinckerhoff (PB) and the range of tests that have been carried out in the laboratory, above ground, at trial underground sites and in active coal mine operations. Although this is a new approach to testing underground VCDs, the method employs recognised testing equipment in a new application. The aim of the new non-destructive technology is to not only verify the thicknessand therefore overpressure rating compliance, of new VCDs, but to allow mine operations t oidentify and locate defects in installed VCDs without causing damage to the material structure.Currently it is difficult, time-consuming and costly to carry out physical sampling and testing ofevery VCD. Therefore, a reliable and accurate means of non-destructively testing concrete andplaster seals in situ will provide substantial operational and safety benefi ts to the underground coal mining industry."

Jun 1, 2012

By V Rasouli, G Cavanough, A Mokaramian

The sampling time, the costs and its quality are the three factors that determine the best method of drilling in mineral exploration. The two principal methods of reverse circulation (RC) and diamond core drilling are often used in combination by mine operators. RC is used for drilling shallow holes and in-pit grade control, and core drilling for deeper holes to identify future resources. The RC method is faster and more flexible than coring and provides virtually uncontaminated cuttings (ranges from dust to 25 mm chips) to the surface cyclone suitable for geochemical anomalies. The diamond coring produces core samples to increase the level of geological knowledge and the 3D extension and distribution of the orebody. However, both of these methods are subjected to certain limitations and inefficiencies in reaching deeper depths and drilling complex hole geometries. Examples of such shortcomings include the inability to provide enough air pressure for RC drilling and high friction between drill pipe and the hole wall in diamond core drilling.Considering that delivering large volume of reliable samples from deep zones to the surface in shortest possible time is of paramount importance in mineral exploration, and assuming that obtaining core samples over whole overburden is not always essential, then drilling small size holes as fast as possible and delivering the small chip samples to the surface would be a good alternative with several advantages over conventional drilling methods for deep hard rocks mineral exploration. As a result, the use of coiled tube (CT) drilling technology has been proposed recently for such applications. CT is a continuous length of ductile steel or composite tube stored and transported on a large reel; and allows fast drilling by eliminating the connection time and providing continuous circulation during drilling. This enables quick access to the zone of interest to collect the cuttings or obtain core samples. CT is advantageous particularly in drilling directional boreholes and multi-laterals. In this paper, feasibility of using CT delivering reliable samples is discussed for deep mineral exploration. In addition, recent developments and practices are presented that make CT a reliable drilling technology to drill cheaper, faster and deeper and to deliver more continuous and reliable data and samples from deep formations.CITATION:Mokaramian, A, Rasouli, V and Cavanough, G, 2012. Quality sampling using coiled tubing drilling in deep mineral exploration, in Proceedings Sampling 2012 , pp 73-80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By C Grobler, M Recklies, G Jiang, I Taylor, M Morgan, G MacDonald, L Smith

The resource estimation of lateritic deposits, such as Aurukun, presents specific issues related to the lateral changes in thickness and elevation of the various horizontal layers (or zones) within the deposit where the x and y dimensions are orders of magnitude greater than the z dimension. The objective was to develop a three-dimensional (3D) block model that retained the vertical and lateral variation inherent in deposits of this type to allow full optimisation of the production plan without prior selection of an economic portion (enriched bauxite layers) of the profile at the resource estimation stage. The Aurukun bauxite deposit is held by Chalco Australia Pty Ltd (Chalco) and forms part of the world-class Weipa bauxite province, Cape York Peninsula, Queensland, Australia. The bauxite is predominantly pisolitic with an upper boehmite-rich zone and lower gibbsite-rich zone. The bauxite consists of both in situ and reworked domains, is overlain by a thin soil horizon and has kaolinite clay as a transitional base. A portable infrared mineral analyser (PIMA) was utilised on site, in addition to elemental assay, on each drill sample to determine the mineralogy, in particular levels of boehmite, gibbsite, kaolinite and reactive silica. As part of the scope of work, a field program was undertaken using large diameter Boart Longyear sonic drilling to acquire detailed density measurements across the deposit to allow compliance with Joint Ore Reserves Committee (JORC) reporting requirements. Interpretation of the stratigraphy was conducted on a hole by hole basis with definition of the zone layering based on stratigraphy, geochemistry and mineralogy. The zone boundaries were then modelled as 3D surfaces and used to constrain a block model. The block model estimation used the ordinary kriging method, with the estimation done in unfolded space and then refolded, therefore maintaining the zones irrespective of thickness or orientation. The unfolding process converts the real-world positions for both blocks and informing samples to a scaled position relative to the roof and floor of each zone. Analysis of the data and variography were also undertaken in unfolded space. The x and y dimensions are unchanged, but the z dimension is a relative position. The effect of the unfolding and limits on number of samples per hole is to æpushÆ the informing sample search sideways but within the stratification, rather than vertically. This honours the strong vertical zonation within the bauxite profile. The JORC Code requires that the stated resource must have æreasonable prospects for economic extractionÆ. This is a qualitative rather than quantitative definition. A number of selection criteria to define a resource roof and floor were developed in consultation with the project engineers and owners to meet these criteria. The vertical selection of material to include in the resource highlights the variation in the development (and destruction) of the bauxite profile from area to area within the deposit.

Jan 1, 2009

By S Hapugoda, J R. Manuel, M P. Ma, L Lu

Iron ore sinter quality depends heavily on the mineralogy, textures and physical structure of the sinter, which is formed upon solidification of the primary sinter melt. The interactions of the initial sinter melt with its surrounding materials will impact on the properties of the primary sinter melt and consequently the solidified structure of the sinter. By using a high-temperature visualisation system, in situ studies have been conducted on the effects of melt compositions (Al2O3, SiO2 and MgO) on the interfacial phenomena of the sinter melt on a natural iron ore substrate. It was found that the melt composition significantly influenced the wettability between the sinter melt and the iron ore substrate. The interactions between the sinter melt and the natural iron ore substrate were also examined. Such interactions can lead to further changes of sinter melt composition and hence the sinter melt properties that, in turn, further affect the wetting behaviour of the sinter melt.CITATION:Ma, M P, Lu, L, Hapugoda, S and Manuel, J R, 2013. Effects of melt composition on the interactions of sinter melt on a natural iron ore substrate, in Proceedings Iron Ore 2013 , pp 431-440 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By J Player, R de Vries, E Villaescusa, R Hassell

Concerns regarding the uncertainty of stope dilution at MMG Dugald River Underground Mine led to a trial stoping program to acquire full-scale comprehensive geotechnical information and to test the validity of the geotechnical and mining parameters. Given that stope production drilling and blasting is a key parameter that influences dilution a detailed stope blast vibration project was implemented. The stoping trial consisted of 19 stopes, a combination of both sublevel open stoping and longitudinal and transverse stopes, of which five were monitored for blast vibrations.The blast vibration project utilised 20 triaxial geophones and five triaxial accelerometers installed in the hanging wall of five monitored stopes. For each stope fired, full blast waveforms were recorded along with detailed information of the blast design. Analysis of the blast vibrations used the Holmberg-Persson approach, with potential damage determined by the relative (Holmberg-Persson) K values.The project identified the benefit of parallel, breakthrough slot holes in reducing blast vibration damage. The results show that radial rings toeing or stabbing into the stope wall lead to higher vibrational energy yield which contributed to increased overbreak. Hanging wall overbreak, by comparison, with parallel, breakthrough blastholes with 1 m standoff, combined with lower density explosive charging (0.8 EP) and increased delays limited blast vibration damage. A number of ring burdens from 1.4 m to 2.5 m were monitored with no difference in terms of energy yield being identified. Changes to the stope drill and blast design are suggested to better control the large blast vibrations and recommendations from this project have been implemented into future mine design and planning.CITATION:Hassell, R, Villaescusa, E, de Vries, R and Player, J, 2015. Stope blast vibration analysis at Dugald River Underground Mine, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 221–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By D A. F Oliveira, C J. Parker

The role of the virgin in situ stress field in tunnelling projects is well known in the Sydney area. The effect of in situ stresses is mostly considered through the use of published relationships that describe the in situ stress conditions as a function of depth. Considering the significant scatter in the data, it is evident that by adopting such relationships, the designers are assuming an average distribution of stresses with depth that is generally a reasonable engineering approach; however, when building a geomechanical model, the tunnelling or geotechnical engineer needs to account for the interrelationship between ground conditions (rock mass quality – fracturing, strength and stiffness) and in situ stress, which may explain part of the stress data scatter. This paper presents an alternative approach for interpreting in situ stress conditions, valid for both Sydney sandstones and shales that focus on such interrelationship between in situ stress and ground conditions.CITATION:Oliveira, D A F and Parker, C J, 2014. An alternative approach for assessing in situ stresses in Sydney, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 189–194 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By K Nilsson, G Cheong

Troy Resources NL acquired a 70 per cent interest in the Mina Sertpo gold project in Goißs State, Brazil, in 2001 following a successful bid for the highly competitive international tender of a tenement package put out by Western Mining Corporation (WMC). The Sertpo deposit is located on cleared grazing land 380 km west of Brasilia and is 30 per cent owned by Amazonia Mineracao Ltda, a private Brazilian company. It is a small high grade open-pittable orebody with a measured and indicated resource of 108 000 tonnes at a grade of 49.7 g/t for 172 500 ounces using a 2.0 g/t cut-off. Troy undertook the project management and development of the project while Amazonia managed the exploration activities and provided other services as required. The project development involved drilling metallurgical test holes, scouring the world to locate an available and suitable second-hand plant, and arranging shipping to andreconstruction in Brazil.

Jan 1, 2004

By N J. Potter, N W. Brand, J M. F Clout

The increasing demand for iron ore with low concentrations of trace elements, puts increasing pressure on iron ore producers for high-quality material. Understanding the mineralogy, petrography, chemistry, and mineral association of iron ore deposits is becoming increasingly important to provide iron ore products that meet the ever-increasing standards of steel mills. Limited attention has been paid to documenting new orebodies beyond bulk RC drill chip assays and product specification data. Therefore, limited information is known about the spatial distribution of minor and trace elements at the hand specimen scale, and elemental deportment within different ore and gangue minerals. In this study, samples from high-grade microplaty hematite, supergene-enriched martite-goethite and hematite iron ores are examined for their elemental and mineral associations. These samples contain distinctive minor and trace element distributions, with the mapping of deleterious elements (eg Zn, As, Cu) enabling the deportment and abundance within the ore and gangue minerals to be assessed. Results from this study show a diverse range of minor and trace mineralogy that are present in typical iron ore samples, in abundances below the detection limit of routine XRD scans, that host the deleterious elements, including but not limited to, sphalerite (Zn and S), chalcopyrite (Cu and S), xenotime (P and Y), apatite (P and Ca), cryptomelane (K and Mn), barite (Ba and S), alkaline feldspar (K, Al and Si) zircon (Zr and Si) and chromite (Cr and Al). The presence of these minerals and associated deleterious elements, even at low concentrations, has implications for producers, with the ongoing restrictions and tightening of environmental constraints in shipped iron ore products. By understanding the distribution and location of these elements within the iron ore, steps can be considered to maintain increasingly higher quality iron ore supply around the world.

Nov 8, 2021

By V Liebezeit

Data management is a significant, but perhaps unrecognised, consideration for any organisation embarking on a geometallurgy program. While resource geologists are accustomed to dealing with thousands or millions of samples and their associated assays, metallurgists and mineralogists have traditionally carried out only a few expensive and complicated tests and consequently tend to manage the resultant data in spreadsheets. The emerging discipline of geometallurgy arrives with significant challenges as a result of the sheer volume of data generated. As an example, the Olympic Dam geometallurgy program has generated more than:60 000 physical subsamples analysed for up to 30 analytes; 25 000 spreadsheet-based laboratory test results; 30 000 sized fractions analysed via QXRD, MLA and/or QEMSCAN;multiple external providers of data, and more than seven terabytes of data. Considerations for any geometallurgy data management system include storage space, data integrity, accessibility, traceability (sample provenance), maintenance and ease of use, integration with data providers and the ability to modify the system to adapt to changing requirements. Further, aspects of a geometallurgy program, such as conducting a range of tests on one sample, producing subsamples such as concentrates and tailings, compositing and routine QA/QC may not be well handled by existing software and providers geared to standard geochemistry, mineralogy or metallurgical test programs. The development of a geometallurgy database using existing software (AcQuire), and the associated file management system will be described for a large geometallurgy program at Olympic Dam. As with many aspects of geometallurgy there is no approach that meets the needs of every site or program. Recognition of data management as an issue, a structured approach in the program planning phase and commitment to executing the strategy will increase the chances of successfully mining the geometallurgical data.

Sep 5, 2011

Initial coal production at Ulan was solely from underground mines. A significant increase in demand for steaming coal in the late 1970's emphasised the need to further expand production and led to the development of the open cut mine which commenced commercial production in June, 1982.During the initial stages of mine planning, feasibility and cost studies were undertaken to determine the most suitable method for coal haulage from the pit. The comparison between a conventional truck haulage system and an in-pit crushing system using a mobile crusher and moveable belt conveyor haulage confirmed that the mobile crusher and conveyor system was superior in every respect for the Ulan mining operations.Technical features and design parameters for the major items of equipment are outlined as well as operating, manning and performance assessments. Minor equipment problems were encountered during initial operation but these have since beenrectified and the plant is now capable of exceeding the design production. Maintenance and energy costs are considerably lower than originally estimated and production efficiencies are continually improving as operators develop new techniques and procedures in the handling of the equipment.

Jan 1, 1985

By S M. J Koleini, F Hedjazi

The purpose of this research was to study the calcination of lead-zinc flotation tailings from the Angouran lead and zinc flotation plant in Iran as a pre-concentration step prior to hydrometallurgical processing of the oxidised tailings. There is an abundance of these tailings in the Angouran region and making use of these tailings would help preserve national wealth and also reduce the serious problems of environmental pollution caused by the tailings. At the optimal conditions of calcining at 750 - 800¦C for 45 minutes, the sample showed a mass loss of about 19 per cent. Mineralogical analyses showed that under these conditions the carbonate minerals including smithsonite (ZnCO3), calcite (CaCO3) and dolomite (Ca Mg (CO3)2) decomposed to their respective oxides. Hemimorphite (Zn4Si2O7 (OH)2.H2O) converted into willemite (Zn2SiO4) and this transformation postponed the formation of silica gel in the leach solution. The grade of zinc increased from 22.20 per cent to 29 per cent. These mineralogical changes resulted in desirable reactions in the acid leach process.

Jan 1, 2004