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By Jaczkowski B

The lower orebody (LOB) at Chingola Divi- sion of Nchanga Consolidated Copper Mines Limited (NCCM) accounts for approximately 30 per cent of the total copper production for the company. The uniformity of the geology of the orebody lends itself readily to a computer based ore reserve calculation and accounting system. The mining units are physically defined such that a hierarchical type of com- puter file organisation can reflect the existing physical interdependencies. In 1972, a project team consisting of one representative from each of the mine planning, operational research, and computer services departments was formed to investigate and to define the technical mining requirements of the dynamic ore reserve system (DORS). The system was finally implemented in 1975ò

Jan 1, 1977

By X L. Liu, W Huang, J M. Zhu, S L. Wu

The shape, position and thickness of the cohesive zone have a great influence on the operational performance of the blast furnace. Many researchers have found that the high temperature properties of iron ores determine the formation of the cohesive zone. The results of this work show that sinter of high basicity interacts with lump ores and acid pellets due to the difference in chemical compositions. The softening and melting properties and the primary slag formation behaviours in the cohesive zone are improved by the high temperature interactions. The high temperature interaction is mainly influenced by the chemical compositions, porosity, interfaces and so on. Although the softening and melting properties and primary slag formation behaviours of lump ore A (a typical limonite lump ore from Australia) is the poorest of the iron ores studied, the high temperature properties of integrated burden A (consisting of sinter and lump ore A) is no worse than the other integrated burdens due to the high interaction between the sinter and lump ore A. It is useful to apply the results in the optimisation of blast furnace burden.CITATION:Liu, X L, Wu, S L, Huang, W and Zhu, J M, 2015. High temperature interactivity of iron ores in the cohesive zone of the blast furnace, in Proceedings Iron Ore 2015, pp 363–366 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A Kondratiev, A E. Moiseev

Viscosity of oxide melts is one of the fundamental physicochemical properties that plays a crucial role in important technological and natural processes like slag flow, slag/metal separation, volcano eruptions etc. However, many oxides melt at extremely high temperatures and are highly corrosive in the liquid state, which makes experimental measurement of melt viscosity by traditional experimental techniques a difficult and expensive, if not unachievable, task. In this case it might be useful to employ other methods of viscosity determination such as modelling or simulation. In the present paper the shear viscosity coefficients of selected pure refractory oxides (CaO, MgO, Al2O3 and others) have been simulated at temperatures above their melting points via the classical molecular dynamics and compared to the available viscosity data (eg experimental viscosities, other model predictions) collected by the authors. The simulation has been carried out using the noncommercial molecular dynamics simulation package LAMMPS and the Born-Mayer-Huggins potential, which parameters for the selected oxides were taken from the literature. Several viscosity calculation techniques (the Stokes-Einstein and Green-Kubo equations, the so called Einstein relations, and the non-equilibrium molecular dynamics methods) have been applied to ensure a more reliable viscosity calculation. It has been demonstrated that the simulated viscosity of the selected melts agrees with the available experimental data. It has also been shown that the simulated viscosity of a number of the oxide melts investigated is close to that calculated by phenomenological viscosity models, which supports viscosity extrapolation from the corresponding binaries and ternaries, if no experimental data is present for unary systems. In general, it has been demonstrated that the molecular dynamics simulation could provide a reasonable estimation of viscosity if no other viscosity data is available.

Jun 19, 2024

By T M. Campos, J Silva, L M. Tavares, J Lichter, L P. Alves, B K. N Rocha, H D. G Turrer

The depletion of the richest ore deposits and the increase in number of mining projects involving deposits with complex mineralogy, higher competence and lower grade has led to an eminent need for improving understanding on multicomponent behaviour in mineral processing. One particularly relevant case is the ball milling of itabirite iron ores fed to the processing plant of Minas-Rio operation in Brazil. Dealing with the two main mineralogical components of the ore, namely hematite and quartz, the operation faces some challenges to improve understanding on how the two components behave in the process. Mathematical models have showed potential to give support in this task, but its applications to describe this type of industrial-scale grinding is still missing. The present work demonstrates the application of a multi-component ball mill model to simulate a closed ball mill circuit with hydrocyclones using the commercial software Integrated Extraction Simulator (IES). Model was calibrated on the basis of bench-scale tests and industrial surveys. Multi-component simulation results are then compared to those considering a single component in the feed, demonstrating the value and great insights that can be achieved by using the former in optimising plant operation.

Aug 24, 2022

By B Vorster, T Medhurst, A Huey

Roof conditions at Oaky North Mine can be prone to stress related damage and/or time dependent degradation. The ability to identify these areas prior to mining has proved challenging using traditional methods. To help alleviate this situation, a study was initiated to investigate methods for roof characterisation using geophysical logs. This involved the use of neutron log data to provide an indirect measure of the proportion of carbonaceous/micaceous laminae present in the immediate roof strata. Detailed analysis of the shale–porosity inter-relationships arising from this analysis provided a means to estimate the proportion of laminations for a given roof interval. This paper outlines the process and how it was used to improve the current GSR modelling and hazard mapping process.

Nov 29, 2022

By V Gupta, Z Huang, S K. Biswal

G-Cell is a new design modification of the Imhoflot pneumatic flotation technology, which utilises a self-inducing aerator inside a downcomer, where bubble-particle attachment takes place. The present study has investigated the suitability of the G-Cell technology for cleaning fine coal using a 0.8 m diameter prototype unit at a coal preparation plant operating in the Midwestern United States. A slip-stream obtained from the overflow of raw coal cyclones operating in the plant, containing nominally minus 150 micron size particles and having ash content in the range of 40 per cent to 50 per cent and sulfur content in the range of 1.30 per cent to 1.50 per cent, has been used as the feed for the G-Cell. The performance data produced from the G-Cell tests are found to be very close to the ideal performance curves produced from release analysis. A statistically designed experimental program has been conducted to investigate the parametric effects on various key process responses, such as combustible recovery, product ash and sulfur rejection. The empirical models developed in this study have been utilised to identify a suitable experimental region for achieving a desired combination of response targets.

Jan 1, 2005

By J M. Galvin

The traditional engineering approach to assessing stability is based on comparing resisting force (capacity) to driving force (demand), or strength to working stress. In underground coal geomechanics, considerable effort has been expended on quantifying the strength of rock structures. However, this has not been matched by advances in determining the load acting on these structures, reflecting a reluctance by some to embrace numerical modelling to assess load magnitudes and distributions. Numerical modelling is a valuable aid as loading environments are a function of both the stiffness of the mine workings and the stiffness of the superincumbent strata and are statically indeterminate in most cases.This paper defines stiffness, which is often confused with elastic modulus. It shows that, effectively, stiffness encapsulates geology, depth of mining, panel width, pillar width and mining height. Therefore, these factors are variables that need to be taken into account when determining stress magnitudes and distributions about mine workings. A range of examples are presented that illustrate the significance of the stiffness of the superincumbent strata on surface subsidence; the magnitude and distribution of pillar and abutment load; and aspects of bord and pillar mining, pillar extraction and longwall mining. These examples provide bases for identifying the limitations of some empirical approaches to mine design, identifying how to compensate for some of these in design processes; and emphasising the need to make greater use of numerical modelling in understanding and quantifying loading environments in underground coal mining.CITATION:Galvin, J M, 2014. The significance of superincumbent strata stiffness and its impacts on coalmine design, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By Y M. Lee, Y Hong, B C. Kim

Since sintered ore is the primary source for producing molten iron in the blast furnace process, maintaining stable quality despite the utilisation of low-grade iron ore is crucial. However, conventional analysis methods, such as chemical composition, ore size distribution and types of iron ore, have limitations in developing the utilisation of new low-grade iron ore and predicting sintered ore properties. Sintered ores are formed through a complex melting process of granule particles consisting of iron ore, flux and fuel. Consequently, it has been investigated that analysis methods which apply the reactive properties of iron ore to predict sintered ore characteristics. In this study, we estimated the properties of iron ore by simulating the assimilation process of coarse ore, which influences the bonding strength of sintered ores and quantifying the degree of assimilation reaction. Pseudo particles were formed by granulating coarse ore (1–3 mm) with adhering fines, which act as primary melts and sintered at 1623 K. The bonding strength of individual sintered ores, formed from 11 different types of iron ore, was measured using a simplified Tumbler Index (TI) test and each value was indexed as the Iron ore Reactivity Index (IRI). By investigating the relationship between the degree of assimilation depending on iron ore properties and the characteristics of sintered ore, we demonstrated that sintered ores formed from more reactive iron ore exhibited stronger bonding strength. Moreover, when blending conditions resulted in a higher Iron Blending ore Reactivity Index (IBRI), the physical properties of sintered ore improved. The development of this analysis method is expected to not only enable careful consideration of iron ore usability but also allow for the advance prediction of sintered ore qualities by deriving the IBRI.

Sep 18, 2023

By Yanske TR, Lane WL

The Doc Run Company and its predecessors have been mining for over 130 years utilising the room and pillar mining method. This method has left approximately 20 per cent of the orebody in the remaining pillars. The original design and planning for the mines did not include extensive pillar extraction. This paper summarises the introduction of the pillar extraction and backfill techniques which have been implemented since 1991. These techniques include the use of low cost fill walls up to 20 in in height and the use of stinger trucks for topping off the fill. In conjunction with these accomplishments, much experience and confidence has been gained in the use of numerical modelling as a method of predicting pillar stability as the mining of pillars progresses. These advances have led to pillar extraction hecoming a major portion of the overall production and have added to the mine life of Doe Run's six operating mines.

Jan 1, 1998

The optimal production of the metals needed by society is best achieved by a close synergy between concentrate production and smelting. For over 75 years commencing in 1923, such a close relationship was enjoyed between the Sullivan Mine in Kimberley, British Columbia and the Trail zinc-lead complex. An effective program of continual change and improvement at the Sullivan concentrator was achieved through a strong entrepreneurial spirit. This spirit was in part maintained through a favourable location in south-eastern British Columbia that resulted in a dynamic local community that has survived the closure of the mine. Innovations to be reviewed include feed forward reagent control, the use of column flotation to zinc and lead cleaning and the application of ultrafine grinding coupled with concentrate dewatering using hyperbaric filter technology.

Jan 1, 2005

By Z Fu, E Topal, O Erten

"Mine waste rock management involving waste rock movement and placement, is a critical aspect in the planning of open pit mining operations, as the waste rock haulage cost can be the largest portion of the mine operating cost. The concept of sustainable development in the mining industry also encourages environmentally friendly waste dumps that have zero hazards to people and the surrounding environment. Therefore, a detailed waste management schedule must satisfy economic and environmental considerations. However, the available tools in the market cannot provide optimal waste dumping schedules to meet all these constraints. This paper introduces a user-friendly and automatic tool to optimise the waste dumping schedule, which minimises the haulage cost, and covers the encapsulation of reactive materials to minimise acid mine drainage problems. This tool has been developed by using a new mixed integer programming (MIP) mathematical model that considers both single-lift and multilift dumping scenarios. The application of the proposed tool on a data set collected from a gold mine shows that the multilift dumping scenario has provided a more flexible and economical waste dumping schedule than the single-lift scenario, and both scenarios satisfy environmental requirements.Citation:Fu, Z, Topal, E and Erten, O, 2016. A Modified Software Tool for Mine Waste Rock Dump Planning, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 229–242 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By C M. Sennitt, M J. Spadafora

Systematic field evaluation of known gold and clay occurrences in South Korea has led to the recognition and discovery of both high and low sulphidation gold-silver epithermal systems. These are associated with Cretaceous acid-intermediate volcanic centres in the southern parts of the peninsula. The high sulphidation deposits such as Seongsan and Kohung are characterised by pervasive silica-alunite-dickite-pyrophyllite alteration with anomalous arsenic geochemical signatures. Gold mineralisation is associated with fine grained marcasite and pyrite. A low sulphidation quartz vein system observed at the Tongyoung mine comprises multistage colloform banded quartz-carbonate assemblages, with minor manganese and base metals. Gold and silver occur as electrum and tellurium minerals. Some deposits such as Gasado and Dogcheon display both high and low sulphidation alteration assemblages. Early pervasive silica-alunite-pyrophyllite alteration caps formed by acid fluids with a significant magmatic component, occur above cryptocrystalline colloform banded vein systems. The quartz vein stage hosts the precious metal mineralisation and appears to have been deposited by later neutral fluids generated in part through mixing with meteroric water.

Jan 1, 1999

By B Clements, R Dunne, J Dioses, S Hart

In April 2003 plant upgrades in the æLow GradeÆ Cadia Hill circuit were undertaken in order to improve concentrate quality and metal recoveries from the flotation circuit. The major changes involved: circuit reconfiguration to allow all concentrates to be reground to less than 38 ¦m prior to final cleaning; increasing ball charge in the regrind mill to fully utilise all of the installed power; desliming of the cleaner scavenger concentrate to improve the circuit water balance; and the inclusion of a gravity concentrator in the regrind circuit to recover more free gold to bullion.Once the flotation circuit had stabilised under the new operating conditions concentrate launder modifications and increased froth crowding on the scavenger flotation cells permitted the introduction of stronger collectors without compromising concentrate quality or circuit stability.Twelve months on, the copper concentrate grade has increased by two per cent and metal recoveries increased by three per cent and seven per cent for copper and gold respectively. The project capital outlay of approximately $2.0 million has been repaid in less than three months. This paper will review the project from the design, construction and commissioning perspective as well as the subsequent debottlenecking exercise that was required to eventually yield the full benefits of this upgrade.

Jan 1, 2005

By C Swamydas

VV Mineral (VVM) group of companies is the largest and the first private producer and exporter of beach sand mineral products in India. During 2010, the company produced and marketed around 750 000 tons of saleable products. Their operations are mainly in the state of Tamil Nadu and Andhra Pradesh, India. Almost all the wet pre-concentration plants use sea water as the concentration medium, since there is no fresh water source available near the deposits. The mines are located along the south-east coast of India in the states of Tamilnadu and Andhra Pradesh. The orebody varies in terms of mineral assemblage, slime content, grain size, and surface coating resulting in different behaviour of the minerals. Three different deposits containing ilmenite of different TiO2 content were studied. The study shows that there is no significant impact of using sea water for wet concentration prior to high tension separation of ilmenite. There is no significant variation in recovery and purity of ilmenite produced from these deposits when wet concentration of the deposits were carried out with sea water as the concentration medium and whether the concentrates were washed with fresh water or not before dry separation using High Tension Roll Separators (HTRS).

Oct 5, 2011

By I Ametov, S Harmer, R Alford

A process that allows selective flotation separation of low Cu/S ratio minerals (chalcopyrite and pyrite) from high Cu/S ratio minerals (bornite and chalcocite) from a mixed copper mineral concentrate under controlled oxidative-reductive potential conditions has been developed. The process has been extensively tested on samples with varying mineralogy using laboratory batch flotation tests and mini pilot plant trials.In this process, the mixed final copper mineral concentrate is purged with nitrogen, and then treated with sodium dithionite to achieve a slurry Eh in the -200 to -100 mV standard hydrogen electrode (SHE) range. Flotation was then carried out using nitrogen gas. As a result, a low Cu/S ratio concentrate (<1.3) and a high Cu/S ratio (>1.6) tailing stream were produced. QEMSCAN analysis of the flotation products showed that more than 85 per cent of the chalcopyrite and 95 per cent of the pyrite reported to the froth concentrate. Chalcocite and bornite were almost evenly distributed between the concentrate and tailing streams.Surface analysis studies, focused on the mechanism of separation, showed that at a negative redox potential xanthate and possibly dixanthogen are the dominant hydrophobic species on the surface of chalcopyrite and pyrite. As a result, the flotation of these minerals remained unaffected. In contrast, a much lower concentration of xanthate species on the surface of chalcocite and bornite particles was observed. Therefore, it is likely that at low Eh the copper xanthate complex desorbs from the chalcocite and bornite surfaces, causing a decrease in surface hydrophobicity and the diminished floatability of chalcocite and bornite.CITATION:Ametov, I, Harmer, S, Grano, S and Alford, R, 2014. Selective flotation of chalcopyrite and pyrite from a mixed copper mineral concentrate under controlled redox potential conditions, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 131–140 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By M Davies, G Theletsane, A H. Gray

Recovery of gold from gold ores has been driven by the available technology and its configuration in the process plant flow sheet.Conventional practice in test work programs has the ore being ground fine (to 106 or 75 microns) to ensure liberation ahead of leaching or flotation. This paper identifies that, in many cases, gold and gold sulfide carriers will liberate and be recovered to a concentrate at much coarser sizes.There is an exponential increase in energy consumption relative to particle size reduction. This impact becomes extreme when comparing crushing a product to 1 mm against grinding to 75?microns.The resultant reduction in energy consumption when liberating and separating at 1 mm or coarser compared to grinding to 75 microns can be in the order of 15 kWh/t or 60 per cent of energy in the comminution circuit.Recovery of free gold and gold sulfide carriers by preconcentration (using continuous gravity devices such as the InLine Pressure Jig), combined with flotation of the fine gold and gold carriers, can result in significant power savings.There are multiple locations within the flow sheet that can be targeted using this process, including recovery in the cyclone underflow of existing plants, preconcentration ahead of the plant or complete greenfield, low-energy process plants designed from first principles based on data from a Gekko developed test work regime.We will describe the process of defining mineralogy in the laboratory and the decision-making process through to actual applications in the field.Several examples will be provided, including a South African Witwatersrand gold ore, several Australian gold ores and others, indicating the benefits of this process and where it has been brought to commercial reality.CITATION:Gray, A H, Davies, M and Theletsane, G, 2014. Coarse liberation and recovery of free gold and gold sulfide carriers for energy reduction in process plants, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 117–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By R R. Lovel

In this paper, life cycle assessment methodology has been used to assess the variations in water use associated with different metal production and processing routes and provide insights into the value derived from water usage in the minerals sector. Using water consumption data derived from the literature it has been shown that the æcradle-to-gateÆ water consumption (or embodied water) for production of the various metals considered in the study ranged from 2.9 m3/t for steel up to 252 087 m3/t for gold. The results largely reflect the grade of the initial ore used to produce each metal, and can be approximated by the following equation: W = 167.7 G - 0.9039 where: W = embodied water (m3/t refined metal) G = grade of ore used to produce metal (per cent metal) The study showed that indirect water consumption in the metal production life cycle, in particular that due to electricity generation, can make a significant contribution to the embodied water value, eg aluminium production. When expressed in terms of m3/t ore, the results for all metals considered indicated that the embodied water is roughly, on average, three times the water consumption of the mining and concentration stage. It was also shown that the economic value per m3 of water consumed for the minerals industry exceeds that for the agricultural and industrial sectors, supporting the view that allocating water resources to the minerals industry has a strong underlying economic basis. Water reforms currently taking place in Australia aim to address issues such as competition for water access, reduced security of supply and increase in cost. Consequently the minerals industry, along with others, can be expected to come under increasing pressure to reduce fresh or raw water use and to integrate water use across sectors. While water recycling is an obvious candidate to help reduce water consumption in the minerals industry, issues such as water quality, among others, will influence the extent to which this can be achieved. In addition, wastewater volumes can be minimised using techniques such as pinch analysis to establish and use the minimum water requirement for the process. The use of dry or near-dry processing technologies, for which the demand for water is small or zero, may be a more radical solution to the water consumption problem; however, it is possible that the introduction of dry processing would bring with it a new set of problems, including dust.

Jan 1, 2006

By T Muzondo, C Prins, D De Vaux, R Schouwstra

The Mogalakwena Platinum Mine in the northern limb of the Bushveld Complex is Anglo American PlatinumÆs only open cast operation exploiting the Platreef. The Platreef, which extends along the basal contact of the Bushveld Complex, is geologically and mineralogically a much more complex orebody than the Merensky and UG-2 reefs. Changes in the footwall and the genesis of the Platreef translate into a number of rock types being present. These rock types vary in hardness and recovery potential and present challenges to metallurgical staff trying to optimise the concentrator. A true understanding of the implications of treating these rock types is required if the maximum value from this orebody is to be obtained.In order to more accurately forecast production and incorporate ore variation in the mine plan and comminution and flotation circuits, a geometallurgical approach to managing the operation has been used and is being further developed.CITATION:Schouwstra, R, De Vaux, D, Muzondo, T and Prins, C, 2013. A geometallurgical approach at Anglo American PlatinumÆs Mogalakwena Operation, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 85-92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By J Li

Cannington Mine has been developing through paste backfilled stopes since the year 2000. These paste drives have been used as either production drill accesses or long-term bypasses. Prior to this study, the ground support requirements for each paste development cut were: an initial 50 mm layer of fibrecrete, weld mesh bolted with 2.4 m split sets, followed by a second coat of 50 mm fibrecrete. Both layers of fibrecrete and the layer of mesh were to be installed before the next cut could be bored and fired. This support regime proved successful at Cannington, however, the total cycle time for each cut was lengthy due to the installation and curing times associated with each layer of surface support. In an effort to reduce the cycle time a study was carried out, with the aid of RocScience’s Phase2 numerical modelling software. The modelling reviewed all of the parameters controlling the stability of a newly excavated development cut. The parameters studied included the early strength of fibrecrete, the ground support load capacity, and the strength of the paste fill masses which varies depending on the cement content. As a result of the study, the ground support standard was revised. The revision has significantly decreased the cycle time as well as fibrecrete consumption, all the while maintaining the safety of personnel and equipment.

Mar 21, 2011

By B Rouvray, R Bertuzzi

The development of a design-and-construct tunnelling project in Australia from its concept to its construction requires designs to be prepared and reviewed at several distinct stages prior to documenting ‘for construction’. On recent projects the post-tender stages have been variously called 30 per cent—70 per cent—100 per cent; or concept–substantial–final; or system definition–preliminary–critical. The design is reviewed at each stage by the designer’s internal reviewer, the contractor and its independent advisor(s), the owner and its independent advisor(s), the project’s independent certifier, proof engineers and often third-party stakeholders and their advisors. Documentation for each stage often dominates the design effort, at times distracting from design. This paper presents the authors’ experience of this design-and-review process. Comparisons of design budget and actual design spend and design program implications are presented. It is postulated that a subtle change has occurred in our industry that has diminished the value of the design dollar. Is there a better process? An alternative is suggested.CITATION:Bertuzzi, R and Rouvray, B, 2014. Reducing the cost of tunnel design in Australia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 501–506 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014