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By Kapoor M. L

EMF measurements were performed in the temperature range of 933-1095 K to determine the thermodynamic properties of oxygen dissolution in liquid lead and lead-tin alloys with tin in the dilute concentration range of 0 to 6 atom per cent. The oxygen in the Pb-O system was varied by equilibrating with (PbO) slag, and that in the Pb-O-Sn system was varied with the addition of lead oxide. Wagner's interaction parameter approach was used to evaluate the self interaction parameter and ternary interaction parameters at different temperatures, to yield: E8(pb) = 97.35 - 113.27 x 103/t Eo(pb) = 139 - 20.616 x104/1' Quasichemical formulation was employed to yield Inf to reveal the effect of tin on oxygen in lead. Results have been predicted on the basis of classical models and those obtained using the QCT approach of Alcock and Richardson at Z=2 have been found to agree with the experimental Data.

Jan 1, 1992

By Elford H. S, Hughes J. F

The object of this paper is to bring before Members of the lnstitute the very important and much discussed question of scientifically prospecting for ores, oil, coal, etc.The paper is divided into three sections:SECTION l - Description of Geophysical Prospecting methods.(1) Sound-Vibration.(2) Magnetic.(3) Gravitometric.(4) Electrical.(a) Equipotential.(b) Electro-magnetic.(c) Schlumberger.(d) General.SECTION II - General discussion of Cicophysical Prospecting.SECTION III - Appendices.(1) Systematic summary of methods of survey.(2) Table of electrical conductivities.(3) Bibliography.SECTION I - DESCRIPTION O:F GEOPHYSICAL PROSPECTING METHODS.(1) SOUND-VIBRATION.THE transmission of sound waves or vibrations underground will depend on at least three factors: (a) Type of Rock. - Hard, dense rocks wiII transmit sound waves much more quickly than softer, more porous rocks. In the former the speed may be eight times that of the latter.(2) Uniformity of Rock. - Any variation in the texture, hardness, etc, wiII have an effect on and direction of transmission of the waves.

Jan 1, 1927

By A Giblett, M Daniel

"The Global Mining Standards and Guidelines Group (GMSG) currently supports nine individual industry working groups focused on developing standards and guidelines for the mining industry. In 2013 the GMSG established the Industrial Comminution Efficiency (ICE) working group to develop freely available guidelines for plant operators to quantify the operating efficiency of industrial comminution circuits. This initiative has engaged a diverse group of representatives from mining companies, equipment vendors, consultants and metallurgical laboratories with vast experience and capabilities in the field of comminution. The GMSG has issued the first two guidelines from the ICE working group in 2015–2016, with the third guideline having completed the approvals process and being in the final stages of editing ahead of release later in 2016.Two of the ICE guidelines present methods to quantify comminution circuit efficiency, and a complementary guideline describes best practice methods to collect the necessary samples and data to furnish these assessments. Collectively the guidelines cover sampling, survey data collection, laboratory testing procedures and calculation processes to allow the user to generate a relative circuit efficiency factor for the comminution circuit at the time of survey. The reference energy consumption is calculated considering the measured F80, P80 and ore strength at the time of survey, using either or both of the Bond or Morrell methods presented in GMSG guidelines dedicated to each method. The guidelines consequently provide the end user with practical tools to perform circuit efficiency analysis and to readily quantify the impact of optimisation efforts.This paper presents the content of the three ICE guidelines and describes their intended application.Citation:Giblett, A and Daniel, M, 2016. Global Mining Standards and Guidelines for Determining Comminution Circuit Efficiency, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Qi P. H

Gold dissolution can be achieved with a number of complexing ligands, all with varying degrees of stability. Processes based on the use of halogens have been known for many years. Beside providing the necessary complex- ing role, the halogens under the appropriate conditions are very effective oxidants for gold. Of the halogens, the gold iodide complexes are the most stable in aqueous solution. Iodine can establish the desired oxidation poten- tial for oxidizing gold, and unlike chlorine and bromine, the oxidizing potential of iodine is mild enough to avoid the oxidation of impurity constituents like metal sulfides. A series of experiments to investigate the fundamental electrochemistry of gold in different halide solutions was performed. Cyclic voltammograms of gold in the presence of 10-2 M chloride, bromide and iodide, respectively show that for a given potential the rate of oxidation is much faster in iodide solution than in either chloride or bromide. An overlay of linear sweep voltammograms for the anodic oxidation of gold in iodide and the cathodic reduction of iodine species on gold provides an effective method for examining the dissolution of gold in iodideftodine solution. The dissolution rates obtained from both electrochemical and actual leaching results are compared. Optimum leaching conditions are analyzed in terms of the iodide/iodine concentrations. Conceptual processes for the recovery of gold and iodide and the regeneration of iodine are discussed.

Jan 1, 1991

By J Hadjigeorgiou

Narrow vein mining, as most types of mining, faces important geotechnical challenges. The specificity of geotechnical challenges in narrow vein mines stems from the nature of the deposits, which are often inclined, discordant and found within fractured rock or faults or in shear zones within country rock. This complicates the construction of representative geomechanical models and limits the applicability of several engineering design tools. Furthermore, in certain cases, the severity of encountered geotechnical problems is considerably greater in narrow vein than in wider orebodies. This paper provides an overview of geotechnical and other challenges in narrow vein mines with a focus on how these are currently addressed. Of particular concern is the use of manual labour working close to the mining face where there is greater exposure to geomechanical hazards. This review concludes with a particular emphasis on understanding the limitations of commonly used engineering tools and techniques to address geotechnical problems in narrow vein mines.CITATION:Hadjigeorgiou, J, 2012. Geotechnical challenges in narrow vein mining, in Proceedings Narrow Vein Mining 2012 , pp 15-22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By J Robinson, L D’Uva

"The Gold Fields group and Gekko Systems have successfully worked together on multiple projects, including at the St Ives, Agnew and Granny Smith operations in Western Australia, and the Damang operations in Ghana, with gravity recovery design, technology installation and optimisation the key driver on each occasion.In 2014, Gold Fields Australia identified an opportunity to challenge the historical thinking at Granny Smith and reassessed the benefit of upfront gravity gold recovery. The historical approach had been to employ gravity on the tailings stream of the carbon-in-pulp (CIP) circuit, recovering sulfide minerals into a concentrate from spiral concentrators for further liberation of gold via a regrind circuit.Gekko was engaged to assess the implementation of a gravity circuit within the grinding area, and to perform a comprehensive gravity recoverable gold test program. Test data was fed into the AMIRA P420 BCC Gravity Model to confirm the gravity recovery potential of the ore, and for process design basis generation. Height, space and capital limitations proved to be a design challenge. However, collaborative learnings throughout the project ensured the design and operation of a reliable and economic gravity gold circuit. Ultimately, the Granny Smith gravity circuit was a success, satisfying all the project objectives and yielding consistent, measurable benefits. On average, the gravity circuit recovers 33 per cent of total gold, resulting in an increase to overall gold recovery by 0.7 per cent.This paper highlights the key project drivers for Gold Fields, and the development of the Granny Smith free gold gravity circuit. It details application of test work and modelling, and the challenges and learnings encountered during the design, installation and commissioning stages. This paper seeks to demonstrate that continuous improvement in a long standing operation can be beneficial to overall circuit flexibility and increased ounce production.Citation:D'Uva, L, Robinson, J and Bell, T, 2016. Defying Gravity - Brownfield Continuous Improvement, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 135–144 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Bellairs P, Stewart JC

On 20 December 1983 at 8.40am blast- hole 57 of Blast RN177 prematurely detonated follwed by a violent deflagration of blast- hole 59 at 10.40am. The blastholes were 380mm diameter drilled in black pyritic Mt McRae shale. The blastholes were loaded with ANFO and primed. Blasthole 57 was stemmed and blasthole 59 was not. A poss- ible mechanism which could lead to such a detonation is described. preliminary tests showed the top 5m of a bench had the highest temperature which could not be influenced by a range of treat -ments. Small scale laboratory tests show- ed that zinc oxide (ZnO) and magnesium carbonate (Mg2CO3) inhibited the reaction. A series of tests using AN with and without inhibitors loaded into the collars of blast -holes drilled in the top 6m of the bench and unstemmed is described. An analysis of the time to reaction of the holes loaded with AN against temperature shows that the decomposition of the AN in contact with the black pyritic shale is probably a sulphuric acid catalysed react- ion. All the inhibitors tested can neut- ralise the sulphuric acid in the shale. 10% ZnO appears to be an effective inhibitor of the reaction providing the AN/ZnO (90/10) is kept out of contact with surface material whose temperature can be as high as 60¦C in summer. It is concluded that ANFO/ZnO (90/ 10) should be now tested in stemmed holes.

Jan 1, 1986

Blast Engineers frequently use the terminology "the blast showed good heave", or even "the heave was better this time". It is reasonably obvious that "good" and "better" are not the best terms to use. It is also noted that any variation in the data can be misleading. The author proposes a more precisely defined and objective set of measures as tried and tested in a project in 1988. Simple objective measurements of a muck pile profile can measure 1. distance thrown 2. spread of material 3. heaping of material 4. skewness, or bias in the heaping 5. rotation of the mass This technique enables one to compare the profiles from different blasts without relying on subjective experience or judgement. Simple, artificial profiles will be presented to illustrate the problems of description; and then application of the measurement techniques to these profies will be discussed with physical interpretations. The mathematical techniques will be presented, and results of the application of the techniques to real data collected during research carried out at Baimsdale in Victoria, will be presented as illustration. The use of these techniques in mathematical modelling will be discussed.

Jan 1, 1990

By N Dube, K L. Sandvik, C Mutevhe

Trojan Nickel Mine is the largest producer of Ni, Cu and Co in Zimbabwe. The mine has operated a nickel flotation concentrator and base metal refinery continuously since 1969, creating 28 million tonnes of sulfide bearing tailings, five million tonnes of permanent waste rock and about seven million tonnes of smelter slag. Exposure of the sulfide bearing minerals renders them susceptible to oxidation in the presence of water and oxygen, resulting in acidic solutions with elevated concentrations of total dissolved solids, sulfate, metals and residual flotation chemicals in various waters draining from the mine site. These pollutants pose a direct threat to the environment and human health, and understanding their deportment and behaviour in the various waste streams is essential in the mineÆs environmental objectives to prevent or minimise adverse impacts arising from its operations. A geochemical assessment of the pollutants was carried out to compute a mass balance between the major sources of pollution and the distribution and fate of pollutants in waste streams from the mine site. Waste rock, tailings, surface water, ground water and sediments were sampled, tested and analysed. Mineral composition and water chemistry data show that geochemical reactions are responsible for the release of pollutants from waste rock, tailings and plant spills. Drainage from the mine area is near neutral due to buffering by magnesium carbonates in the fine fraction of the tailings. The natural wetlands that exist downstream of the waste rock and tailings dams are effective in reducing metal loadings to water courses. However, solutes and heavy metals are occasionally released to surface and ground water, when their concentrations peak during the dry season. The results demonstrate the necessity to understand the natural chemical processes that characterise the distribution of pollutants in nature and how such knowledge can be used to develop cost effective methods to remediate pollution in the natural environment.

Jan 1, 2006

By S J. Loach

F-Series reconciliations are formal comparisons of estimates and measurements of ore quantity and quality made at pre-determined points along the mining value chain. F1 is the ratio of ‘Depleted Grade Control Ore/Depleted Long-term Model Ore’ and validates the models upon which Resource and Reserve statements are based. F2 is the ratio of ‘Produced Tonnes and Grade/Depleted Grade Control Ore (-) Changes in Pre-Crusher Stockpiles’ and validates that the ore tonnes and grade delineated in the pit are being accurately extracted and correctly delivered to the processing plant. These factors provide important corporate assurance for a mining company by providing quantitative feedback on model-predicted tonnes and block grade estimates. Since 2009, BHPs Western Australian Iron Ore F-Series reconciliations have been calculated in a single, centralised sequel-server database. This software routinely collates data regarding mineral resource block model depletions, grade control model depletions, pre-crusher stockpile inventories and production tonnes and grade measurements and then calculates F-Series factors for both tonnes and product quality. This paper will present case studies where reconciliation factors were used to identify improvement opportunities leading to projects that improved our models and subsequent forecasts of production tonnes and quality. In addition, it will show how reconciliation factors are tools that monitor control during periods of rapid change and provide feedback on the effectiveness of improvement projects.

Sep 18, 2023

By S Jayakumari, E Ringdalen, V Canaguier

Silicomanganese (SiMn), containing approximately 16–30 per cent Si, is produced in submerged arc furnaces using various Mn sources and quartz as the primary raw materials, along with fluxes and reductants. In the high-temperature zone known as the coke bed, a silica-rich slag is formed. SiMn is produced through the reduction of SiO2 from the slag. Dissolution of quartz into slags with different compositions, the primary slag formed from the Mn sources and flux before any MnO reduction occurred, representing conditions at the top of the coke bed, and dissolution of quartz into a partially reduced slag to simulate conditions inside the coke bed has been investigated. Experimental investigations were carried out to study the dissolution of quartz particles of varying sizes, 5 mm and 25 mm in synthetic slags with different compositions at temperatures between 1400°C and 1600°C, with varying holding times. Observed results are compared with liquidus compositions and equilibrium phases for original and formed slags. Particle size has been shown to be of little importance for the dissolution. Quartz dissolved more easily in slag at top of the coke bed than slag in the coke bed. Complete dissolution was observed after 30 mins at 1600°C in all cases, but not after 0 mins.

Jun 19, 2024

By S H. Algie, D P. Taplin, S G. Doig

"Suboptimal performance of clusters of hydrocyclones (cyclones), relative to the performance of the individual cyclones that comprise the cluster, is a common phenomenon. The primary cause is well known: uneven distribution of the slurry feed into the individual cyclones. The direct result of uneven distribution is that each cyclone in a cluster performs somewhat differently. Hence, some, if not all, of them do not work at their intended operating points, and the classification is not as sharp as intended. The impact on grade, recovery and milling efficiency will vary depending on the duty of the processing circuit, but the most immediately apparent consequence of uneven distribution is a difference in wear rates in the individual cyclones; this exacerbates the problems of unequal performance of the individual cyclones. In severe cases, and as differential wear proceeds, flows from the individual cyclones may become visibly different. Uneven distribution, once the phenomenon was identified, was seen to be a significant issue in the high-solids hydrocyclone cluster in the ball mill recycle section of Evolution Mining’s Edna May Operation (EMO, Westonia, Western Australia) gold processing plant. In 2012, a FloCEP® hydrocyclone feed distributor system was installed to alleviate the problem. Over the next four years of operation, this innovation has proven its value in the metallurgical and maintenance areas. Individual cyclones now wear at the same rate, greatly reducing the need for operator intervention, as well as increasing overall plant availability through minimising unplanned maintenance. The costs of the installation can be justified by savings in maintenance alone, though the greatest value, as is described in this paper, is in allowing the plant to produce consistently closer to its operational design limits. The FloCEP® system is a low maintenance, readily installed retrofit, based on two patented devices that are combined with complementary proprietary design methodology allowing customisation for specific flow rates and slurry particle properties. Together, these devices produce and distribute a pseudo-homogenous slurry flow without moving parts.Citation:Taplin, D P, Doig, S G and Algie, S H, 2016. Experience with FloCEP® Slurry Flow Conditioning at Evolution Mining's Edna May Operation, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 251–260 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By D Anderson, W Timms

"A geotechnical centrifuge can characterise and model the interaction of tailings and fluids over very long time periods by accelerating drainage and consolidation processes. This technology can be considered an environmental ‘time machine’ for designing and evaluating tailings storage projects and verifying numerical models. The Broadbent G-18 geotechnical centrifuge (2 m diameter, up to 875 rev/min) and associated equipment is a unique facility commissioned in 2011 at UNSW Australia for applied research in low-permeability materials such as mine tailings. Two centrifuge modules are available: the permeameter module for characterisation and physical modelling and the strongbox module for physical modelling.This paper presents examples of geotechnical centrifuge applications for the: consolidation of slurries and dewatering design of earthen barriers compatible with tailings chemistry prediction of contaminant mobility. The specifications and capability of the UNSW Australia geotechnical centrifuge and associated instrumentation is also presented, along with preliminary analysis of the confidence intervals associated with permeability testing of a set of samples of varying heterogeneity. Drainage velocity through a mine tailings sample increases linearly with g-level in the centrifuge permeameter until tailings consolidation occurs. Alternatively, geotechnical centrifuge experiments can be designed to limit consolidation so as to quantify permeability changes that may occur with geochemical interactions between fluids and mine tailings or earthen containments. Reactive solute transport through mine tailings can be simulated at realistic solid:liquid ratios when chemical equilibrium is maintained during geotechnical centrifuge testing. Carefully designed physical models of tailings disposal tested at accelerated gravity can therefore provide a realistic evaluation of tailings consolidation and drainage and the potential for subsurface migration of contaminants from mine tailings over long time periods.CITATION:Timms, W and Anderson, D, 2015. Geotechnical centrifuge technology for characterising the interaction of tailings and pore water over decadal time periods, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 247–252 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 27, 2015

Vertical flow systems (SAPS, vertical flow wetlands) are increasingly used for passive treatment of mine drainage that is net acid. Data on 30 systems in eastern US show that well designed systems typically add about 40 g/d/m2 of alkalinity to influent net acid water. If they are designed with a conservative loading rate of 25 g/d/m2 and carefully constructed, they produce net alkaline water. Alkalinity added depends on influent acidity, Fe, pH, and retention time, and ranges widely, from 7 to 484 mg/L, so this is not a useful design criterion. Some waters may benefit from retention times longer than the conventional 12 - 16 hours, but the design must be partly based on cost-benefit considerations. Systems with fine limestone added to the compost layer perform better than average, perhaps to an alkalinity generation rate of 80 g/m2/d. A variety of problems are noted in the 30 systems and others reported in the literature. Systems with high influent Fe (> ~75 mg/L, varying with pH) tend to gradually decrease in flow rate because of precipitation and settling of Fe hydroxides on top of the compost layer. Some high-Fe systems precipitate Fe in the limestone layer, suggesting inadequate compost thickness, or short-circuiting through thin spots. Systems with Al exceeding about 10 mg/L tend to plug because of Al hydroxide precipitation in the limestone layer. Flushing only removes a small part of this precipitate, but can extend life. Some systems are ineffective because of failure of the inflow system. Some systems are uneconomic because they are oversized. A continuing program of inspection and maintenance is necessary for long-term performance.

Jan 1, 2003

By G Malherbe, J Gonzalez, D C. Franklin, J Bassan, C T. Farrelly

To respond to ever-increasing challenges, mining companies have been experimenting with new business models and technologies in order to speed mine development, production, processing and transport. The various experiments involve mobile access to data, intelligent sensors, advanced analytics, virtual collaboration, virtual reality, automated equipment, remote operations centres and strategic partnerships. A synthesis of all these components creates a ænetwork effectÆ that can dramatically improve the overall effectiveness the entire operation. The concept of the Network Centric Mine borrows from a variety of industries, including defence, aerospace, aviation, petroleum, utilities and manufacturing. Central to the concept are improvements to the way we connect people, process, information and technology, resulting in a more highly collaborative business model, with roles and processes designed to take advantage of new technology. The components of the mining operation act as a connected network aimed at a common goal, regardless of the boundaries of organisation and location.The design of this new organisational ecosystem needs to take into account the recent advances that enable the æplug and playÆ integrated collaborative environment, including cloud computing, mobile devices and social networking, as well as advances in augmented reality, robotics, geo-location, digital labelling, simulation and analytics. However, the most consistent lesson from other industries is the need to properly enable the behaviour and process changes necessary for success.Benefits from adopting a network centric approach include the more effective use of scarce expertise, improved data and information analysis, reduced process variance, and more informed and faster decision-making. The future of mining will see more technology savvy workers who will drive the adoption of new processes. The operations will shift from a relatively static and disparate set of functions, to a digitally aware, dynamic, automated, integrated and interactive environment, with increased agility, lower operating costs, higher productivity and improved safety.CITATION:Farrelly, C T, Malherbe, G, Gonzalez, J, Bassan, J and Franklin, D C, 2012. The network centric mine, in Proceedings International Mine Management 2012, pp 143-160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

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 G King, Q Shu, W Cao, F Gyakwaa, H Singh, S Wang, M Huttula, T Fabritius

Metallurgical slag, such as refining slag, is essential to enhance or promote steel cleanliness. The CaO–MgO–Al2O3–SiO2 system is the primary source of oxides-based inclusions. It plays a vital role in applications in various pyrometallurgical processes. Numerous thermodynamic databases and physicochemical properties of slag studies mainly focus on quenched samples and measurements at room temperature. Consequently, the present study explored the physicochemical, structural properties and crystallisation evolution for CaO–MgO–Al2O3–SiO2 glassy slags via in situ hightemperature Raman spectroscopy and synchrotron X-ray diffraction. The study was carried out by synthesising CaO–MgO–Al2O3–SiO2 slag with varying Al2O3/SiO2 ratios. The results from the in situ high-temperature measurement demonstrated a pattern showing a transformation of a broad peak from the glassy matrix to crystalline peaks. The study showed crystallisation of dominant phases such as Ca2SiO4, Ca2Al2SiO7 and CaAl2O4 that correspond and are attributable to changes of structural units during in situ high-temperature measurements. The results further showed a correlation between an increase and transformation in crystalline phases observed from the spectra obtained from non-isothermal heating of the samples.

Jun 19, 2024

By I M. Platten, Y Xie, B W. Cuffley, S C. Dominy

"Geometallurgical programs require the collection of representative samples for geochemical, mineralogical and metallurgical test work. Such protocols must be designed to suit the style of orebody in question. The distribution, proportion and size of gold particles have a direct impact on the effectiveness of sampling and test work protocols, and the gold recovery processes employed. Characterisation studies focusing on ore mineralogy, and gold particle deportment, size and distribution are required. High resolution X-ray computed tomography provides a non-destructive method for analysing the 3D nature of gold in rock samples. It can be used to calculate the modal abundance, particle size and distribution of gold in the sample volume. This paper presents a case study of the imaging of in situ gold particles in a high-grade gold ore. The Nick O’Time reef system comprises laminated quartz veins, which locally bear extreme grades of up to 100 oz/t gold. The mineralisation has previously been characterised from both a mineralogical and metallurgical perspective. Eight visible gold-bearing vein samples were scanned using X-ray microtomography. Microtomographic data were integrated with previous mineralogical and metallurgical test work outputs.CITATION:Dominy, S C, Platten, I M, Xie, Y, Cuffley, B W and O’Connor, L, 2016. Characterisation of Gold Ore from the Nick O’Time Shoot (Tarnagulla, Australia) Using High Resolution X-ray Computed Tomography, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 241–254 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By L C. P J Fonteneau, B Godel, E R. Ramanaidou

The Hamersley Province in Western Australia hosts large iron ore deposits. Each deposit displays various iron ore types that were defined on their metallurgical properties, especially in terms of porosity and mineralogy. Conventional porosity and mineralogy information on iron ore types are provided on 2D thin sections using automated image analysis with scanning electron microscopy (SEM)-based techniques combined with chemical analyses. However these techniques cannot accurately quantify the 3D porosity. High-resolution X-ray computed tomography (HRXCT) is a non-destructive technique providing a 3D image of the sample with a resolution close to 0.5 - 0.7 ¦m for samples size of up to few centimetres in length. 3D image analysis using customised algorithms now provide accurate quantitative porosity and mineralogy of iron ore types.CITATION:Fonteneau, L C P J, Godel, B and Ramanaidou, E R, 2013. Application of high-resolution x-ray computed tomography to iron ore characterisation, in Proceedings Iron Ore 2013 , pp 243-250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By A Sinuhaji, H Kalangi, T B. Setyoko

Ore fragmentation at the DOZ block cave mine is highly variable, both as a function of rock type and column height of draw. Initially, the mine was constructed and equipped with limited capability to handle drawpoint oversize material. Significant issues with drawpoint availability and achieving overall mine production targets resulted. A suite of secondary sizing tools was added to the mine equipment fleet over a one-year time frame. Although significant oversize continues to be experienced, use of the correct secondary breakage tool for each particular oversize or hang-up occurrence has resulted in increased drawpoint availability, production rate, draw compliance, and operator safety. Currently, a range of secondary breakage techniques is being utilised to size material for delivery to the primary crusher. Run-of-mine material (3) is directly mucked to ore passes fitted with grizzlys that have one-metre square openings. Ore containing small boulders (>1 m3, 3) is loader-trammed to ore passes fitted with rockbreakers. Medium-sized boulders (>2 m3) accessible from the drawpoint are drilled with Sandvik Tamrock Commando drills. Boulders hung-up within the drawbell are drilled and charged with a Sandvik Tamrock Secondary Breakage Unit. Compacted, fine-grained muck is blasted utilising 55 mm cartridge powder concussion bombs.

Jan 1, 2005