Search Documents

By B Snook, G Rollinson, R Fairhurst, R Herrington

Nickel laterites constitute a significant proportion of the worldÆs Ni reserves and are considered environmentally friendly alternatives to traditional sulfide resources. Subsequently they are of increasing significance for exploration and production. To be successfully exploited, however, they require an understanding of the relations between mineralogy, texture, grade and recovery. The development of automated quantitative mineralogy can aid in the characterisation of the ores to help improve extraction and processing methods. Recent developments in hydrometallurgy have resulted in relatively straightforward recovery of Ni in silicate (saprolite and smectite) ores. However, the extraction of Ni from limonitic ores is more complex. It requires a detailed understanding of the iron-hydroxide species and other, potentially interfering, oxide and hydroxide compounds. Particularly the relations between the Ni-bearing goethite and Mn, Al and Cr may adversely affect the economic prospects of an ore. Manganese can adversely affect the selective recovery of Ni and Co from solutions but has also been highlighted as a significant potential by-product (cf, Zhang and Cheng, 2007). Aluminium hydroxides can be significant acid consumers leading to an increased expense of extraction (Johnson, Cashmore and Hockridge, 2005). Chromite is resistant to acid attack, but chromium in goethite may adversely affect the dissolution leading to a retention of Ni (McDonald and Whittington, 2008). This study presents an investigation of oxide and hydroxide species in laterites using QEMSCAN« EDS/SEM-based automated quantitative mineralogy. Samples were collected from Turkey (¦aldag), Albania and the Philippines. Particular emphasis has been placed on the development of a quantification for Ni-poor and Ni-rich goethite.

Jan 1, 2008

By K Ellis, B Lumsden

A full-scale statistically-based on/off plant trial of a new flotation conditioning technology designed to improve fine mineral recovery was undertaken to determine whether the recovery of selected fine sulfide minerals can be increased. The technology is selective for certain sulfide minerals only, including chalcopyrite and sphalerite. The technology has been shown to selectively aggregate the fine chalcopyrite and sphalerite minerals giving increased flotation recovery. The plant trials have shown an increase in the mineral recovery, without decreasing selectivity. Size by size recovery shows a significant increase in the fine (

Jan 1, 2005

I The South Platform of the Gippsland Basin is an extensive area of shallow basement covered by a relatively-thin Late Mesozoic-Cainozoic section. Although the sporadic exploration to-date has not resulted in any hydrocarbon discoveries, the area is under-explored and its taste potential has not yet been fully evaluated. The best potential appears to be in areas underlain by the Golden Beach Megasequence where structures are mainly related to basement fault blocks.

Jan 1, 1992

The phosphatic overburden of Christmas Island is a lateritic soil and consists dominantly of crandallite and millisite. These minerals are polymorphs of general formula, (Na,K)x Ca2-x (Al, Fe)6 (PO4)4 (OH)10-x (2+x) H2O. Iron occurs only in millisite. Both minerals exhibit similar thermal transformations, dehydroxylating near 600¦C and recrystallizing above 800¦C. Dehydroxylation results in crystal structure collapse but retention of crystal morphology. Ggethite, boehmite and apatite are minor constituents of some-of the phosphatic Soils.

Jan 1, 1971

By J W. Dong, Y M. Li, J L. Tian, Z H. Jiang

Electroslag remelting is widely used to produce various special steels, mainly because of its ability to provide high cleanliness and excellent homogeneity of ingot. Undoubtedly an optimal slag plays a key role in removing inclusions and enhancing the mechanical properties of a specific special steel. In order to improve the metallurgical performance of the slag in electroslag refining of die steel, a variety of slags have already been developed using traditional trial-and-error methods. Nonetheless, these slags may not be inherently optimal for the specific requirements of actual die steel refining processes. In this work, we have designed a CaF2-CaO-Al2O3-SiO2-MgO quinary slag system using genetic algorithms method aiming to remove the existing large size inclusions (D and Ds type) in high quality die steel. The comprehensive effects of five components (CaF2, CaO, Al2O3, SiO2 and MgO) were studied based on existing fundamental theory. The slag composition was screened considering the parameters such as melting point, electrical conductivity, calcium ion concentration, and appropriate viscosity etc. Furthermore, the candidate optimal slag was applied in the industrial production of die steel by electroslag remelting method. The detection results indicate that majority large inclusions (D and Ds type) have been successfully removed, showing significant advantage to traditional slags. This result has demonstrated the genetic method to be efficient and reliable. In addition, depending on the personalised demand of other steel and alloys, this method allows for the adjustment of the screening frameworks and processes to develop the candidate optimal slags. This method has not been reported previously in the field of electroslag composition design, and compared with the traditional trial-and-error method, the new method will save a lot of time and experimental costs.

Jun 19, 2024

Models of the genesis of existing ore oodles and targetting of exploration for new mines are greatly enhanced by an-understanding of the plate tectonic environment existing at the time of mineral emplacement. In areas of recent or active tectonism, a study of the present-day crustal and upper mantle structure is an obvious starting point in unravelling the evolution of the accessible upper crust. Bougainville is the northern-most island in the Solomon Islands arc. A 7km deep trench almost 100km off its western coast marks the commencement of subduction of the Solomon Sea plate beneath the Pacific plate. As outlined by the seismicity, the subducted crustal slab under the southern half of Bougainville reaches the axis of the island at about 100km depth, from which point it dips near vertically another 300km into the upper mantle. Large surface blasts at the Bougainville Copper Mine at Panguna, Bougainville, Papua New Guinea were used to derive an unreversed upper crustal profile of the island. The crust appears to be relatively simple, being comprised of a 5km deep layer with a P-wave velocity of 4.5km/sec, overlying a l0km thick layer with a P-wave velocity of 7.2km/sec. Constraints on the 15km mantle depth were provided by the identification of both P to and S to P phase conversions of seismic waves from local shallow earthquakes at the Moho boundary. An upper mantle velocity of 7.95(¦ 0.15) km/sec was measured from travel times of selected shallow earthquakes along the strike of the island arc.

Jan 1, 1987

The Kaltails Project is situated close to the city of Kalgoorlie-Boulder in Western Australia. Located on the south-eastern fringe of the Golden Mile, Kaltails has been in operation since June 1989. The tailings forming the reserve for Kaltails have been derived from 100 years of underground mining on the Golden Mile, but, some of the re.;erve has been retreated in the past. A map of the tailings reserves and treatment plant site is presented as Figure 1. The gold project is a joint venture between Poseidon 90 per cent and Gold Corporation (ten per cent) and is managed by Poseidon Gold Kaltails.

Jan 1, 1992

By M I. Pownceby, N A. S Webster, A J. Studer, I C. Madsen, J A. Kimpton, M J. Fisher-White, L Lu

In situ synchrotron X-ray and in situ neutron diffraction-based experimentation have been implemented to characterise the formation of the complex calcium ferrite iron ore sinter bonding phases silico-ferrite of calcium and aluminium (SFCA) and SFCA-I. Experiments were carried out using fine-grained (<20 ¦m) sinter mixtures containing ~77 wt per cent Fe2O3, 14 wt per cent CaO, 3.5 wt per cent SiO2 and 5 wt per cent Al2O3, with diffraction data collected during heating until 1300 - 1350¦C, which was enough to ensure complete melting of the SFCA phases. In the case of the in situ synchrotron experimentation, results showed that altering the nature of the starting sinter mixture (ie substitution of goethite for hematite; substitution of an amorphous Al2O3-based mineral for gibbsite) did not have a significant effect on the thermal stability range of the SFCA phases. It did, however, have a profound effect on the formation and rate of consumption of the calcium-rich ferrite phases C2F and CF, and on the formation mechanisms of SFCA and SFCA-I. The in situ neutron diffraction experimentation is the first described in the context of iron ore sintering, and the observation of both SFCA-I and SFCA formation in the in situ diffraction data represents the first step in achieving the goal of charactering iron ore sinter phase formation in large volumes of industrial sinter starting materials with a wide range of particle sizes (up to 6.3 mm).CITATION:Webster, N A S, Pownceby, M I, Madsen, I C, Studer, A J, Lu, L, Manuel, J R, Kimpton, J A and Fisher-White, M J, 2013. In situ x-ray and neutron diffraction studies of silico-ferrite of calcium and aluminium iron ore sinter phase formation, in Proceedings Iron Ore 2013 , pp 487-494 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By S Graskoski, S Craig, C Myburgh

Too often in mine planning, maximising revenue-generating material takes precedence over minimising costs. The ability to target both revenue and cost optimisation enables mine plans to fulfil corporate objectives of targeting maximal project net present value (NPV). The state of current mining costs and increasing government regulations in Australia are forcing many mine planners to pay closer attention to cost minimisation. Dumping waste material, which ultimately forms waste landforms, represents a large cost to mining operations. A general mine, with a waste to ore strip ration of 6:1, allocates approximately 32 per cent of total mining costs to waste haulage alone (Gregory, 2003).Most scheduling packages do not dynamically build economic or minimal cost dumps as part of the scheduling process. In most cases, waste dumps are built after a mining schedule has been defined. Automated software is now available which dynamically schedules the pit and waste dumps together. The overall shape of the waste dump is therefore dictated by minimum cost or minimum haulage hours.The purpose of this paper is to compare dynamic pit and waste schedules to traditional methods which apply haulage estimations after defining the mining schedule. This paper includes a case study on the large open pit operation at Tropicana Gold Mine, a joint venture between AngloGold Ashanti Australia Ltd (70 per cent) and Independence Group NL (30 per cent). The operation will focus on mining three large open pits over a 13-year mining life. A total of 397 Mt of waste is mined and directed to multiple destinations including waste dumps, the run-of-mine (ROM) pad and tailings storage facility (TSF) perimeter.Due to these complexities, management of the haulage fleet, especially during the critical period of operation readiness and start-up, is essential. Critical infrastructure such as the TSF and ROM pad will need to be built early and these areas, as well as the sequential development of the waste dump, will need to be developed within the constraints of structured mining fleet build-up.This paper investigates the influences of haulage estimation accuracy and compares traditional approaches for waste planning to automated approaches using EVORELUTIONÖ.CITATION:Graskoski, S, Craig, S and Myburgh, C, 2013. Dynamic pit and waste dump schedule optimisation at Tropicana Gold Mine, in Proceedings World Gold 2013 , pp 121-128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The Quiruvilca district, located 80 km east of Trujillo in north central Peru (Fig. 1), has produced over eight million tons of Cu-Pb- Zn-Ag ore from approximately 60 veins since 1789. "Quiruvilca means "sacred tooth" in Quechua, the lingua franca of the Incas. The expression refers to a prominent volcanic neck exposed several kilometers northeast of the district. The district covers an area of approx- imately 24 km2. The mines occupy the eastern quarter; workings underlie 6.7 km2 with a developed vertical range of 280 m. All pres- ently operating workings are owned by Corpora- cion Minera Nor Peru S.A., a subsidiary of ASARCO Incorporated. The oldest rocks in the area are Lower Cretaceous clastic sedimentary rocks exposed 7 km to the east. Lithologies include sand- stone, siltstone, shale, coal seams, and carbonates (Cossio, 1964). These rocks were folded and affected by regional low-grade metamorphism during the early Tertiary, 40-65 m.y. (Hollister, 1977).

Jan 1, 1987

By A L. Randriamanjatosoa, G Small, C Greet

In flotation simulation models, the effects of pulp chemistry other than pH are often ignored and reduced to particles hydrophobicity or contact angle, neither of which can be measured readily in real time in an operating plant. The flotation response of a given sulphide mineral is known to be influenced and can be improved by changing the chemical characteristics of the pulp during grinding and flotation. The on-line measurement of pulp pH, potential, dissolved oxygen, temperature and oxygen demand of a process stream was completed with the PCM® (Pulp Chemistry Monitor) developed by Magotteaux in this study. The data generated together with relevant plant operating parameters were used to construct an empirical model and simulate the metallurgical performance of the ore. The same approach was also applied to laboratory flotation tests data using various grinding media types. The flotation models better fit the actual data when the chemistry of the pulp is taken into account.CITATION:Randriamanjatosoa, A L, Greet, C and Small, G, 2018. Effects of pulp chemistry on plant and laboratory flotation modelling, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 423–432 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Oda Y, Hashiuchi M

In the smelting section, flexible fuels such as coal or coke are used in place of heavy fuel oil in order to utilize energy sources more efficiently. Heat recovered from the off gas of the furnace has been converted by the waste heat boiler into steam, which is used for self power generation and for heating or maintaining various temperatures. The amount of the recovered steam in the smelter is currently increasing due to maximum utilization of powdered cokes. The heat source required to maintain the temperature of the electrolyte in the tank house is electric power and steam. However until recent year this steam was provided by its own heavy oil combustion type boiler in the tank house since the amount of steam consumed in heating the electrolyte is large. Though experimental work over the last few years has shown the advantages of reducing steam in the tank house by fully covering the cell, the implementation of the full cover can lead to other operating problems. However various improvements, mainly the covering of the cell with a simple device, have led to greatly reduced steam consumption. As a result, steam for the tank house is now provided by the waste heat boiler only bringing more efficient energy usage.

Jan 1, 1987

By Dickin FJ

Advances in the development and application of in situ imaging of mineral processing operations using electrical tomography techniques are reviewed and illustrated with case studies relating to pneumatic conveying, mixing and centrifugal separation processes. The potential for applying these methods to full three-dimensional visualisation of the dynamic behaviour of flow in pipelines and separators, and the resulting consequences for process-modelling strategies, are discussed.

Jan 1, 1993

By P Mikula, R Geranmayeh, R Carlton, M Ferguson, R Whiting

The concept of using specially designed slot blasts to mine through stress abutments that intersect faults, while controlling fault-slip seismicity, has come of age at Mt Charlotte Mine. Due to the high and adverse stress field and the presence of major faults, the mine is vulnerable to significant fault-slip seismicity. As mining proceeded, advancing stress abutments around various mined areas encroached on several major subvertical faults. If the sequence formed a diminishing pillar between stope and fault, the removal or failure of that pillar daylighted the fault, and often resulted in significant fault-slip seismicity. A new strategy called ‘Tight Slot Blasting’ (TSB) was developed to restrain or dampen this style of fault-slip movement. The TSB has geometric similarities to a conventional cut-off slot used to create stress shadows, but its function is different. Its objective is to trigger and control a sudden shift of the stress state on a fault from an initial stable state, through an unstable transition, to a second stable state. A TSB firing advances a long tall narrow slot through a stressed abutment between a stope void and a nearby fault, using a rapid blast with a low swell ratio, so that the slot substantially and rapidly fills with blasted rock fragments. During the blast process, the stressed rock is rapidly removed and transformed into the fragmented rock fill in the slot. The strategy deliberately allows a fault-slip episode to manifest at a chosen time and place. The tight-packed broken rock in the slot performs an essential shock-absorbing function by controlling the slip amount and rate on the fault, while at the same time the fill becomes compacted by the movement. This controls the dissipation of fault-slip energy, and greatly reduces the seismic response in time and space. A small closure across the slot occurs, with consequent relaxation and destressing of the adjacent rock mass. Stress monitoring data shows that slot creation lowers the abutment stress in the nearby rock mass, while the newly placed fragmented rock fill acts as a shock absorber, providing considerable resistance to substantial fault-slip movement that otherwise could deliver a significant seismic event. First used in 2007, the strategy has been refined to become a routine specialised practice for management of seismically hazardous situations at Mt Charlotte, with 12 successful TSBs conducted to date. Despite mining through multiple high stress abutments, seismic reactions have not exceeded ML 2.1 with any TSB firing, all remaining below the site tolerable maximum of ML 2.3. This paper presents an overview of the strategy, and five case examples of the strategy in critical stressed areas in July 2016, Sept 2017, Dec 2017 and two in Oct 2020. The strategy has successfully managed the seismicity and is expected to remain an essential part of the seismic management plan at Mt Charlotte Mine.

Nov 29, 2022

By S J. Kim, S W. Kim, L Tomas da Rocha, S Jung

Al2O3 has been regarded as a harmful gangue component in iron ore, especially causing reduction degradation in industrial sintering of iron ore. The current study aimed to utilise low-grade iron ore containing high Al2O3 content in sintering process. In order to counteract the adverse effect of Al2O3 on reduction behaviour of iron ore sinter, mill-scale and calcined dolomite were chosen as FeO- and MgO-bearing materials. Firstly, mill-scale was added to high Al2O3 sinter and addition was optimised as 10 wt per cent, then calcined dolomite was added further. Magnetite and magnesio-ferrite were identified as the major phases in iron ore sinter when adding mill-scale and calcined dolomite. As the dosage of calcined dolomite increased beyond 4 wt per cent of in sinter mix, unreacted MgO particles were observed, which is ascribed to the limitation of MgO dissolution into magnetite matrix. Both mill-scale and calcined dolomite were effective in improving compressive load and Reduction Disintegration Index (RDI) of iron ore sinter although its reduction degree was highly decreased. The addition of both FeO and MgO-bearing materials to high Al2O3 sinter has a potential to improve the sinter quality, also contribute to the recycling of industrial by-product. However, the amount should be optimised in views of phase development and deterioration of reducibility.

Jun 19, 2024

By Reichardt Y

Fine feed fractions in the size range from 1 to 40 ¦m of materials with different hardness as limestone and silicon carbide have been stressed in two different devices. A tungsten-carbide-blodc allows a single stressing with a pressure up to 2000 MPa and a 4-piston-block enables a multiple stressing procedure in which the material bed is stressed in alternating directions with a pressure up to 700 MPa. The experiments show energy absorption as the major factor for the interparticle breakage of hard material, like quartz, zircon silicate, silicon carbide and smelted oonindum, pressure, however, does not influence the results within the investigated range from 100 to 700 MPa and even up to 2000 MPa for corundum. But the breakage of the middle-hard limestone depends on the pressure so far as more fineness can be produced if the same energy is introduced at a lower pressure level. The creation of very fine and microfine fragments decreases strongly with increasing hardness of the feed materiaL The energy consumption for producing microfine material with a multiple stressing procedure on a particle bed is much lower than that one of a usual milling process. But this procedure needs a classification with a seperation cut at a couple of microns, which is not easy to accomplish.

Jan 1, 1993

By R Cox, S Pandey

The coal seam gas (CSG) industry is expanding rapidly in the Surat and Bowen basins. CSG production involves pumping water from the coal seams to release the gas adsorbed to coal particles. The reduction in water pressure in the coal seams will cause some reductions in water pressure in overlying and underlying aquifers because there will always be some interconnectivity between the formations. The Surat Basin is a sub-basin of the Great Artesian Basin, which contains aquifers of high economic, environmental and cultural value. The Condamine Alluvium is also an important water resource, which overlies parts of the eastern margin of the Surat Basin.Under the Queensland (Qld) regulatory framework, an area of intensive CSG development involving multiple CSG operators can be declared to be a cumulative management area. For such areas the Office of Groundwater Impact Assessment develops assessments of future impacts on aquifer water pressures and develops and manages arrangements. The results are published in underground water impact reports.The Surat underground water impact report (QWC, 2012) was approved in December 2012. This paper summarises the place of the report in the Queensland regulatory framework, the content of the report and progress in its implementation.CITATION:Cox, R and Pandey, S, 2013. Managing groundwater impacts in the Surat Basin, in Proceedings Water in Mining 2013 , pp 169-174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

As partition curves are widely employed to characterize screening efficiency which, by definition, should include a time parameter, it is shown, perhaps for the first time, that time is already included in the partition curves and how. Laboratory and plant results are used to show how screening efficiency depends on feed composition, near-mesh and oversize material and screen motion, and how these factors may combine to give an erroneous result that two identically efficient screens are different and two screens of different efficiency are identical. Reasons are given which show why a renewed interest in screening would benefit not only screen engineers and operators but also those concerned in formulating standard specifications of screen analysis methods.

Jan 1, 1984

By C Nyoni, T Nguyen, C R. W Seymour, G D. Dempers

Unplanned dilution directly adds cost to production from mining, milling, tailings disposal and administration. Additionally, unplanned dilution decreases the productivity, profitability and may affect the planned life of mine. Identifying and quantifying the potential for unplanned dilution allows optimisation of the mining plan and mining practices to minimise the adverse impact on productivity and the cost of production. The Dilution Rating System (DRS) has been developed to more accurately predict dilution thickness and the variable potential for dilution, from individual stopes to life of mine planning. The DRS utilises the methodology developed for the Mining Rock Mass Model (Seymour et al 2007, Jenkins et al 2009) to generate a three-dimensional dilution rating model, which is then calibrated against stoping performance. Dilution can be predicted more accurately and the parameters affecting dilution can be determined and minimised through improved mining techniques, for example blasting and ground support design. Potential high dilution areas can be identified in the planning stages of the mine and systems put in place to mitigate the risk of excessive dilution. This paper presents the methodology used to develop the DRS and then successfully predict dilution for both the hangingwall and footwall of stopes at the Gara Gold Mine. This has enabled the expected dilution to be more accurately predicted and mitigated where possible thus reducing unplanned dilution.

Mar 15, 2021

By F Weir, B Estrada

The impact of seismic loading on open pit slope stability in Australia is often only considered where the slopes are located adjacent to tailings facilities or other major infrastructure. The debate regarding application of seismic loading in open pit design in Australia is usually founded on limited reporting on significant damage of open pit operations during earthquakes, the common perception that earthquakes do not occur in Australia or that they are unlikely to occur during the mine life of the mine. It is frequently overlooked that pit slopes that have withstood strong earthquakes in highly active seismic regions are often designed under strict seismic guidelines. This paper discusses the factors that impact earthquake performance of open mine slopes. These factors include topography, slope geometry, rock material and mass properties, water management and intrinsic pit design. Further, the paper presents insights into the characteristics of earthquake activity in Australia such as magnitude distribution, earthquake depths, areas prone of earthquake activity and general seismic hazard that are relevant to pit design. Guidelines are provided on the conditions and circumstances under which earthquake design in open pit mining should be considered. In addition, this paper provides recommendation on the applicable methods for assessment of the impacts of earthquake loading on pit slope stability.

Jun 22, 2022