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Acupan is considered to be an intrusive centre as several igneous phases have been emplaced in the vicinity of the mine over the past 8 Ma. They include the Lucbuban gabbro, Virac granodiorite, Ampucao dacite porphyry (ADP), Hartwell plug, Itogon plug and the multi-phase Balatoc diatreme. These intrusives have high-K calc-alkaline affinities and are grouped together as the Virac Complex.Porphyry-style mineralisation formed during the final crystallization of the ADP in the late Pliocene, with the deposition of two vein stages from high-temperature hypersaline magmatic-hydrothermal fluids. K-silicate alteration halos surround the first stage of veinlets (stage I); they are surrounded in turn by a propylitic assemblage. White sericite and/or intense propylitic halos envelop the second stage of veinlets (stage II) and grade into a weak nrnnvlitir accPmht o

Jan 1, 1990

FOR some years past it has been usual to specify high-grade copper for use for many purposes, but the practice of specifying zinc of a high degree of purity for certain purposes is of comparatively recent origin. It is a practice, however, which is extending ag the effect of the impurities in zinc on products manufactured therefrom becomes widely recognized.The notes hereunder are intended to briefly survey the principal uses to which high-gr.ade zinc is being put, and, wherever possible, to indicate the effect of the impurities normally present in the lower grades of zinc.In the United States zinc is graded into five divisions, known respectively as "High-grade" "Intermediate" "Brass Special" "Selected," and "Prime Western." The maximum amounts of impurities allowed in the various grades are indicated in Table I,which is compiled from data published by the American Society of Testing Materials:In addition, it is specified in an cases that the slabs shall be reasonably free from surface corrosion or adhering foreign matter. Although zinc used in Europe has in many cases been sold on analysis it is only recently that any attempt has been made to grade...

Jan 1, 1923

By N Lima, A Piçarra, L Filippov, I Filippova, M Marques, K Silva

The iron industry produces a considerable amount of tailings per annum, due to its substantial volumes of production. The actual iron ore processing routes require the removal of slimes fractions. In addition to iron oxides and quartz, the iron ore slimes are generally composed of other minerals such as kaolinite and finely dispersed iron hydroxides which impact significantly the performance of reverse cationic flotation. In this study, we propose a two stage processing route that would allow further beneficiation of iron slimes which are not successfully beneficiated, avoiding their disposal as waste. The new amidoamine reagent was tested as a collector in a two-stage route to process two samples of iron ore slimes with d50 close to 10 μm and with high kaolinite content (13 to 20 per cent). The results showed that it was possible to obtain iron concentrate with 66.5 per cent iron and 48.4 per cent mass recovery for a feed containing 48.9 per cent Fe associated with hematite (39 per cent) and goethite (32 per cent). The collector efficiency was improved by mixing with frother for the slimes with higher goethite content of 55 per cent: the concentrate grade was increased from 58.8 per cent to 64.5 per cent with addition of the frother at the expense of reducing operation metallurgical recovery from 87.8 per cent to 75.6 per cent. The efficiency of the process was improved by applying an external energy impact to disperse the fine particles and clean the surface of the minerals. The new amidoamine collector does not require a depressor such as corn starch and may provide the development of new concentration routes for complex ultrafine iron ores. The combination of the amidoamine-based flotation at first stage with high intensity magnetic separation allowed development of optimised two-stage processing routes to valorise the iron ore slimes rejected to the tailings in the actual flotation plant.

Sep 18, 2023

One of the strategies introduced within Pasminco Mining to survive low commodity prices is to formally implement a `Quality Education System'. The net result has been a consistent approach to quality within and across mine sites. This `quality system' has been adopted in the technical computing environment and the immediate benefits have been: ò A clearer understanding of the systems, processes and relationships that involve technical computing. ò A re-focussing on customer (user) requirements. ò Inclusion of managers as customers with their own requirements of performance and quality, in addition to access to Executive Information. ò New ways to measure the `performance' of a technical computing environment which includes using maintenance costs. Observations are that there is an overlap between `traditional' information technology (IT) methodologies and quality systems being put in place in the broader workplace. This overlap is most apparent in the area of analysing customer requirements. In the IT environment customers are viewed as users, and their requirements determined by undertaking a requirements analysis. A data flow diagram traditionally used in the IT environment and not as a tool in quality systems, has been used in a novel manner to help identify the customers of the technical computing department. It has also been useful in illustrating the work processes and relationships between the entities in this diagram and in directing the future initiatives needed to fulfil the customers' changing requirements.

Jan 1, 1995

The mining industry was one of the first industry groups to be confronted by and to respond to public and government pressure to improve its environmental management. Companies operating in New Zealand and the parts of Australia with firmer environmental and planning controls responded quickly with environmental staff appointments to their development and operating arms. Even in less demanding jurisdictions in Western Australia and Papua New Guinea environmental staff were added to the payrolls. The issues then and now were seen as pollution related with land and water housekeeping leading to progressive or eventual site rehabilitation. Increasingly, however, environmental issues are being recognised as being more complex. They are about equity and social justice. Pollution of water, air or land is seen by the public as a question of personal and public rights, more or less wherever the pollution takes place, on public or private land. Environmental issues in mining have become caught up in the global perspective and a more holistic approach to environmental management. Environmental issues touch every comer of the community and action is being demanded. Nowhere is this better illustrated than on Bougainville Island where increasingly militant demands by land- owners for redress for environmental degradation from the Panguna Mine, on close examination, revealed many years of disenchant- ment with the government and the mining company over a wide range of social, cultural and environmental issues. Failure to address this satisfactorily eventually led to a bloody rebellion and finally an act of secession.

Jan 1, 1991

By M Akbarpour, M Osanloo

In mining industries, materials handling costs represent a significant component of the operational cost. A variety of methods have been applied in surface mine equipment selection in order to select the suitable loading system with the lowest loading operation cost. These are queuing theory, bunching theory, linear programming and genetic algorithm. Among them, genetic algorithm is a simple method and applied for preliminary selection of the loading system. In this study, gathering information from anomaly No 2 of Gol-e-Gohar iron mine of Iran, loading system (number and its capacity) has been optimised by genetic algorithm. The study results showed that two shovels 8.25 m3 are required for the removal of 60 million tonnes of overburden. After removal overburden, these two shovels contribute to the extraction of 42 million tonnes of ore with a stripping ratio of 1:1.

Jan 1, 2007

Welcome to Mount Isa- my home city and without doubtthe base for what promises to be the most exciting mineral development yet seen in Australia.Mr. Chairman, it also gives me great pride to representthis area in the Queensland State Parliament as well as being the Minister for Minerals and Energy in the Queensland Government.Mount Isa is now part of the Australian mining industry folklore.It is all what a good mine is all about. It is. all what a good community is all about.

Jan 1, 1993

By D Corley, J Moore, M Grant, A, W R

Resource estimates are the corner stone of technical and investment decision-making. Prior to mining, resource estimation uncertainty has the greatest potential to lead to poor investment decisions, despite a significant component of resource estimation uncertainty being unknowable at this critical stage in the mining cycle. This presents a conundrum to the resource geologist in terms of risk evaluation and resource classification. Ahead of mining, there is normally considerable focus on drill hole spacing analysis to determine the ‘optimal’ drill hole spacing, taking grade and geological continuity into account; cost-benefit analyses balance improved resource definition against cost; the law of diminishing returns and the exponential cost increases acting together as spacing is reduced. Typically, a lower limit to the drill hole spacing is identified. After completing the resource drilling to an agreed spacing, resource estimation is then undertaken. At this point it is common to attempt to bracket the resource estimation uncertainty. In many cases conditional simulation is used, based on a modelled, but largely assumed, variogram model. It is also assumed that the histogram of the available drill hole sample data is representative of the in-ground mineralisation. The purpose of this paper is not to diminish the importance of drill hole spacing and simulation studies, but rather to illuminate an important aspect of estimation uncertainty that, although previously recognised, is typically overlooked – the question of how representative the available data set is in characterising the true (but unknown) distribution of mineralisation. To do this, we lift the lid on one of OceanaGold’s former operations, the mined-out Globe Progress Mine, by resurrecting a high quality, close-spaced, reverse circulation (RC) grade control data set. The Globe Progress Mine is within the West Coast Region of New Zealand, it was closed and transitioned to rehabilitation in 2016 and is now known as the Reefton Restoration Project. The exhaustive Globe Progress grade control data was used to repeatedly ‘redrill’ the deposit by extracting 35 m × 35 m spaced subsets from the original 5 m × 5 m spaced grade control data. Utilising closely spaced grade control data removed the need for assumptions regarding short range continuity, which are necessary with forward-looking analyses that are based upon broader spaced resource drilling. The extraction process used a nearest neighbourhood algorithm, repeatedly moving the origin in 5 mE, or 5 mN increments. Individual resource estimates were then completed for each of the extracted drill hole data sets (49 in total) as well as a grade control estimate based upon the exhaustive data set. Whilst the data unpinning each of the 49 estimates changed, the geological assumptions, variography, and modelling parameters remained constant. This approach was taken to isolate the impact of changing the input data. The 49 estimates were then compared against each other and the grade control estimate. The mean of all 49 sensitivity estimates was close to that of the grade control estimate in terms of contained gold, tonnes and grade. Whilst it is acknowledged that the grade control estimate itself is subject to some degree of estimation uncertainty, the close match between the average of the 49 estimates and the grade control estimate suggests that the resource estimation methodology is reasonable and appropriate. Whilst this comparison is important, the focus of this study is on the component of estimation uncertainty related to the underlying data, and this is reflected in the spread across the estimates. The spread across the 49 global estimates (highest to lowest) for this particular Mineral Resource Estimation Conference 2023 | Perth, Australia | 24–25 May 2023 142 case study was found to be significant (approximately 20 per cent in grade and metal) and that is attributable solely to the underlying data. This exercise quantifies a component of the estimation uncertainty that is inherent to all drill hole data and is distinct from the uncertainties associated with modelling methodology choices, sample and subsample quality and drill hole spacing-related interpolation uncertainty. Importantly, this uncertainty is unknowable prior to mining; we can only directly compare the resource drill hole data against grade control data after mining has taken place. For the case study, approximately 65 per cent of the estimates fell within 5 per cent of the grade control estimate for contained-gold, suggesting that for many projects the histogram of drill hole data is unlikely to differ noticeably from that of the in-ground resource. However, about 15 per cent of the estimates in this study differed by more than 7.5 per cent, suggesting that a not-insignificant proportion of estimates will be materially compromised. Whether or not the available drill hole data is representative comes down to the ‘luck of the draw’ and cannot be known at the time of resource estimation. Given the challenge of attempting to evaluate forward-looking estimation uncertainty, a component of which that can only be quantified retrospectively, what should we do as resource geologists? What are the implications for risk evaluation, resource classification and reconciliation? Furthermore, without rigorous post-mining data checks, resource geologists may conflate suboptimal modelling with the shortcomings of the underlying data. An example of this problem is discussed in the following section.

May 24, 2023

Environmental management of minesites in general, and management of water discharges in particular, is receiving ever-increasing attention. One key component in the successful design and operation of water management systems is to address the presence of sediment in the water being conveyed. Sediment erosion in the mining environment is often greatly exacerbated by disturbing the ground surface of vast areas of catchment. If sediment avoidance, transport, deposition or release are not adequately addressed, the impact on water management facilities can include loss of storage and hydraulic capacity, more frequent equipment replacement, increased operational costs and potentially environmentally unacceptable sediment discharges to receiving waters. An overview of sediment management within water facilities is presented here, and design of one particular approach, the use of settling basins for sediment removal, is discussed in detail. Examples are used to illustrate lessons learnt where particular approaches to sediment management have been found to be lacking. The common themes in the lessons learnt include the need to characterise hydrodynamic conditions and sediment properties in the water source, to set performance targets for sediment management, and to develop operating procedures to meet these targets under a realistic range of scenarios. The examples show how analysis of expected performance of sediment management can help with planning of operation and maintenance strategies. For settling basins, use of a simulation model that includes the effects of turbulence on settling can provide considerable benefits in optimising basin design and evaluating performance. Even in the most basic approach to sediment settling, establishing performance targets based on design flow and sediment characteristics is critical.

Jan 1, 2003

By M Haest, O Dominguez, D Mittrup

Technological innovations and emerging analytical capabilities are transforming the way drill samples are analysed, with real-time mineralogical analysis made possible. In addition, new business/technical requirements are challenging long standing processes to incorporate more sources of information during planning in order to improve compliance to plan during mining and processing. Unfortunately, the new sources of information that are added do not always have adequate protocols in place to ensure quality data is collected.Spectral data covering the visible – near – short wave – midwave – longwave range are routinely collected by the Geoscience and Exploration department at BHP Billiton Iron Ore for accurate mineralogical identification. These data are used for geological interpretations (logging and modelling) and prediction of physical variables (metallurgical and geotechnical properties).This paper introduces how sampling and quality assurance / quality control concepts have been applied in the spectral data process. The described routine for sampling, data collection/management and reconciliation has been developed to track system precision and accurately and consistently ensure the data is of high quality before it is used across the mining chain.CITATION:Mittrup, D, Dominguez, O and Haest, M, 2017. A new approach to implement quality assurance and quality control to technological innovations – quality of spectral data capture and processes in the minerals industry, in Proceedings Eighth World Conference on Sampling and Blending , pp 265–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Littlewood E

We offer these notes as a practical contribution. All the arguments we advance have been tested by practical experience.In its preparation we realised that our subject was one of such importance and covered so wide a field that, dealt with by one of us alone, it might easily have been too much for him, so we have endeavoured, by mutual criticism and advice and a pooling of ideas, to bring forward a few points that may be of advantage to members. If any of the paper is of benefit to mining on the "Golden Mile," or elsewhere, we shall feel amply repaid for our efforts.It is obvious to all that the longer the machine is working productively per shift the greater the return, to all concerned; the machine-man himself and the company. Furthermore, if a man commences a shift with a definite objective in view; for instance, to bore and fire a specific cut, which he recognizes will give him a good financial return, then that man will exercise all his capabilities to attain that objective.In this paper we hope to demonstrate the value to the machine-man of the knowledge of the capabilities of each hole he bores, so that he will be enabled to utilize his drilling time to the greatest advantage. Also, we hope to show that such drilling time can be advantageously extended.After the war, with the influx of new men to the industry, some education on the finer points of machine work may be desirable, and any instruction in this branch must stress the realization of the value of each hole.We realise that most of those present have a sound workable knowledge of machine-mining, and we are not trying to teach anyone the fundamentals of machine work, but we would like to bring to their attentIon some of the finer points which we believe are very important.The machine-man has control of gear of a capital value of over £150, and the use or misuse of that material has a direct bearing on working costs. Therefore it is imperative that the capital outlay is gainfully employed.A "bogger" in charge of a 5/- shovel engaged unproductively is bad enough. How much worse for £150 worth of gear to be not fully productive.Figs. 1 and 2 demonstrate angles of break, and the full realization of the importance of this angle is essential to our paper. Although these Sketches are two-dimensional, we hope they will be sufficient to demonstrate our meaning. We will pass over them as briefly as possible.Fig. 1 shows three holes asked to perform an identical task.(a) 7-ft. hole bored 2 ft. into solid ground-will not come out.(b) 4-ft. hole bored 1 ft. from solid ground-will come out easily.(c) 5-ft. hole bored to solid ground-the best that can be expected under general conditions encountered.The angle of break is a right-angle, normal to direction of hole.

Jan 1, 1944

By Tullemans FJ

This paper describes the general approach to ore reserve estimation and mine planning used at the Kidston Gold Mine. The geological setting and exploration is briefly summarized for background information.A geostatistical study of the deposit was carried out to determine the geological ore reserve. This was confirmed using a manual polygonal technique. Optimum pits outlined by a Lerchs-Grossman open pit design algorithm were manually smoothed allowing mineable reserves to be calculated. Mine production schedules based on kriged block grades and tonnages are continuously updated using production blasthole assays. An arithmetic mean technique of block grade estimation has proved successful to date. After milling approximately 4.9Mt of ore, the mill grade of 2.13g Au/t is only 0.5% above the mine estimate of 2.12g Au/t. The difference in contained gold between "As staked" blasthole reserves and kriged mineable reserves is 3.8%. The application of blasthole kriging as a basis for ore/waste classification in erratically mineralized areas is being evaluated. Planned future developments are briefly mentioned.

Jan 1, 1986

By C B. Smith, G L. Boxer, S W. Moss, A L. Jaques, V Lorenz, M J. Rayner

The Ernest Henry Iron Oxide Copper Gold deposit is hosted in a large dilation between two moderately dipping shear zones found in the footwall and hanging wall of the deposit. These shears are controlled by a large diorite intrusion to the north-east and south-west of the deposit, formed ~1660 Ma. A shear zone dubbed the ‘Interlens’ uncovered through underground workings truncates the main orebody into two lenses, and is hypothesized to have formed in conjunction with the Hanging Wall Shear Zone and Footwall Shear Zone. All three shears dip moderately to the SSE (50–140) from open cut exposures through to the current mining horizon approximately 800 m below the surface. Routine geological work and a capital drilling campaign has identified a significant flexure in these sub parallel ore bounding shears with increasing depth. A shift in shear orientation in the Interlens over approximately 100 m vertically from ~50° to the SSE to a steep, easterly trend (~85° to the east) is observed in both drill core and exposures in the underground workings. It is hypothesized the diorite intrusive to the south-west of the deposit controls the shear zone geometries at depth. The geometry of the Interlens mirrors the surface expression of the Proterozoic package of the orebounding shears to the south-west of the deposit, suggesting the surface geometries of the shear zones are consistent with depth. Additional drilling to explore the validity of this hypothesis is planned for the near future to better understand the structural controls on the Ernest Henry mineralisation with increasing depth.

Mar 22, 2022

By F C. D Michelin

As mines get deeper, the critical underground temperature limits will be exceeded, and an increasing number of mines will need to implement, expand or modify cooling systems. Surface cooling plants have many advantages over underground cooling such as efficient heat rejection, and lower relative capital cost; however the delivery of cooling through long underground distances can result in lost refrigeration capacity before the chilled air reaches the areas it is needed most. Refrigeration plants are therefore often overdesigned in size and capacity to compensate for underground losses.More mines are now utilising real-time monitoring and automated control of ventilation airflow and fan systems to ensure the conditions underground are safe and productive, and power consumption is efficiently managed. There may be significant opportunities to extend ventilation monitoring and control into the refrigeration delivery and control system.Energy reduction is an effective way to reduce costs and CO2 emissions, which is an increasingly important part of corporate governance. More efficient refrigeration control is a further step toward reducing energy consumption. This paper looks at an added step in how real-time monitoring can assist in controlling the output and chilled air delivery of a cooling plant. The requirements, implementation, benefits and challenges will be discussed.

Oct 12, 2022

By Komosa T

The increase in the proportion of sulphide ore treated by the gold mining industry has led to generally higher oxygen requirements. Additions of pure oxygen, hydrogen peroxide and in some cases calcium peroxide, have been proposed as a means of satisfying the oxygen demand and overcoming the problems from reactive sulphides in the ore. Current oxidant addition options and practice are reviewed.Laboratory oxygen demand tests are reported for a suite of ores to show some of the effects of pH and preaeration.Laboratory leach tests at high and low dissolved oxygen levels are reported on two of the ores with higher oxygen demands, and the results are assessed in terms of gold leaching kinetics, ultimate gold extraction, and cyanide requirements.

Jan 1, 1992

By D Gerrard, J Begelhole, J Gerber

The Iron Magnet deposit has been mined since 2007 when Arrium (then OneSteel) commissioned the magnetite concentrator to supply feed to the pelletising plant in Whyalla. The concentrate quality requirement for the customer required consistent product with minimal variability. In the early stages of operation, it was identified that the feed variability introduced significant changes in the concentrate quality, which was outside the acceptable customer limits.In 2011, a geometallurgical regression model was developed that allowed for the estimation of concentrate quality produced from the feed material. This was based on a laboratory-scale Davis Tube Recovery (DTR) test performed on the feed material. The objective of the project was to characterise the raw ore in the pit to allow for blending prior to crushing. By blending the feed to the concentrator, minimal concentrate quality variation within the plant was achieved. The orebody was divided into geometallurgical classes, called ore types, based on the mineral texture and magnetic mass recovery. Each geometallurgical class consisted of material with similar metallurgical performances. For each individual blast pattern, the ore was grouped into the geometallurgical classes and a composite sample was created. The composite sample was put through the laboratory-scale DTR test and the results were used to estimate the metallurgical performance of the material.The characterisation process and feed pile build methodology was applied in early 2013 and went through an optimisation and streamlining phase. Since the implementation of the geometallurgical characterisation process, the plant has seen a significant reduction in concentrate variability and measurable throughput gains. The characterisation process has also increased the amount of material that is now classified as ore.CITATION:Gerber, J, Gerrard, D and Begelhole, J, 2015. Geometallurgy of the South Middleback Ranges magnetite deposit – predicting plant performance from the pit, in Proceedings Iron Ore 2015, pp 555–560 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By S Pradhan, A Kuras, R Mahajan

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

Sep 17, 2014

By Quast K. B

Laboratory batch rod and ball milling tests were conducted on samples of Heavy Medium Separator (HMS) sinks from Renison Tin Limited. The product size distributions for this heterogeneous material were very different to similarly sized homogenous material previously reported by the authors. The effects of pulp density on product size distributions were only evident at pulp densities greater than 80 per cent solids. At high solids density, the major weight distribution product peak fell and broadened indicating less efficient breakage, particularly for rod milling. Tin distribution in the ground products was also affected by pUlp density, and there was always less cumulative per cent tin than cumulative per cent weight, ie there was no tendency for cassiterite to slime down to 10/lm.

Jan 1, 1995

In order to fully understand why Amax Coal puts such extreme emphasis on the drilling and blasting programs at each of our mines, we must review the past. This paper will discuss the drilling and blasting techniques we used in the 1970s and their evolution to current practices. As time progressed, major changes influenced the surface mining of coal through new more restrictive governmental controls and local communities organising into groups with two goals in mind, one to shut down the mines and the second to try and get rich by making false and unjust damage suits against the mines. In virtually all of our midwest surface operations we have at one time or presently are facing litigation that has reached into the millions of dollars. Amax Coal has worked in co-operation with the United States Bureau of Mines in the areas of blast vibration, shot design, highwall safety, blast casting studies and many more. Today we are continuing to work with Dr David Siskind and his expert staff seeking answers to old and new problems addressing the blasting of overburden and parting seams.

Jan 1, 1995

By A Batnasan

The main techniques for removing phosphorus as an impurity element in iron ores are physical separation (eg magnetic separation, flotation) and chemical separation (acid leaching, alkaline leaching and bioleaching) processes. When phosphorus occurs in iron ores as phosphate minerals (eg apatite), physical separation techniques are available to remove the gangue minerals from iron ores. On the other hand, chemical separation techniques are suitable for reducing phosphorus levels when phosphorus is associated with iron oxides and hydroxide minerals (eg hematite and goethite) in iron ores. In this study, the dephosphorisation behaviour of high‐phosphorus iron ore was investigated using a combined alkaline roasting and water washing route. Roasting experiments were conducted in a laboratory electric muffle furnace using various concentrations of sodium hydroxide (0–50 g/kg-ore) at different temperatures (100–800°C), varying prolonged roasting times (0–2 h), and different particle size fractions (-45 – -250 μm) of iron ore. Subsequent water washing experiments were employed at various pulp densities (30–1000 g/L) and different times (30 s – 60 min) at ambient temperature. Hematite and goethite were the main minerals in the high-phosphorus iron ore identified using X-ray diffraction (XRD) analysis. The iron ore assaying 63.40 mass % Fe (total), 0.240 mass % P, 4.53 mass % SiO2, and 4.87 mass % Al2O3 were determined using X-ray fluorescence (XRF) analysis. The results showed that the dephosphorisation rate of the iron ore was reached 40 per cent under roasting with 50 g/kg-ore NaOH at 300°C for 2 hours followed by water washing for 30 s with a pulp density of 300 g/L, reducing phosphorus level from 0.240 mass % to 0.142 mass %. At the same time, the iron grade was reduced from 63.4 per cent to 59.5 per cent, caused by an iron loss. Results suggest that the phase transformation of goethite induces the dephosphorisation of high-phosphorus iron ore under alkaline roasting conditions

Aug 22, 2022