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Publications (182)
Adequate characterisation of the clays is becoming increasingly important as operating mines move into areas of more complex mineralogy, and new mines commence with more complex ores. The processing requirement in both situations is the need for better mineralogical characterisation to identify problematic ore and plant minerals before issues arise...
The global demand for the copper metal is continuously increasing however, the high-grade copper ore deposits are constantly depleting. As a result, ore bodies with complex mineralogy characteristics and rich in arsenic-copper bearing minerals are increasingly processed. Arsenic-copper sulphides such as enargite can represent a significant amount o...
There is an increasing trend in the extraction and development of copper resources from complex deposits. These complex deposits pose mineral processing challenges, as they often contain low grade disseminated copper ore with high levels of impurities particularly arsenic. Arsenic is a naturally occurring element, however its presence in ore deposi...
Talc and mica are major gangue minerals in many base metal ores including sulfide ores. Talc is a naturally hydrophobic mineral, and therefore it is easily floatable. There have been many studies to overcome this problem, and depress talc with various reagents. In this study the flotation of a copper ore in the presence of talc and muscovite was st...
Context: Accurately predicting the flotation response of composite particles is important for estimating the ultimate mineral recoveries of an ore. In this study industrial data was used to demonstrate that existing particle-surface composition approaches (Yoon et al., 2016; Ford et al., 2011; Evans, 2010; Ralston et al., 2007) failed to accurately...
Context: The flotation response of composite particles is a complex phenomenon where theoretical predictions are not always supported by experimental results. A prediction often applied to composite particles is to consider their surface composition (as represented by perimeter composition in particle cross-sections) and the flotation characteristi...
Recent research has demonstrated promising results showing the possibility of separating arsenic-copper sulphides from other copper minerals by controlling the potential of the flotation pulp. Most of these studies were conducted on single mineral systems, and the selective removal of arsenic-copper minerals in real ore systems is not well understo...
Flotation is one of the most important primary separation processes in the minerals industry. As far as the mechanism of flotation is concerned, turbulence is one of the key parameters determining flotation performance because it affects three main processes: suspension of particles, air dispersion and particle-bubble collision, attachment and deta...
One of the key drivers of geometallurgy is to define the ore characteristics and their variability
to build a geometallurgical model. The inclusion of waste rock properties and their variability
is just as important, given that the generation of acid rock drainage (ARD) poses one of the most
significant environmental challenges facing the mining in...
Turbulence is an important factor that affects flotation performance, which needs to be incorporated into flotation models. However, the measurement of turbulence in industrial flotation cells is difficult because of the highly abrasive and aggressive slurry environment. This has made the development and validation of models incorporating turbulenc...
The deleterious effects of clays on flotation performance are widely acknowledged but the mechanisms involved are not clearly established. Moreover, the concentrations beyond which clay minerals become problematic are not clearly defined. One major parameter is the difference between swelling and non-swelling clays which is evaluated in this study....
This case study briefly highlights the potential to derive, in an approximate sense, likely processing behaviour from geological reconstructions. In turn, this information can feed into geometallurgical planning allowing the early stage recognition of potential processing flowpaths that can be used to optimise recovery. The case study is pulled tog...
To accurately predict the flotation recovery potential of mineral particles it is essential to consider in particular the mineral composition of their surfaces (Gaudin, 1939). For composite particles the behaviour is frequently approximated by considering the behaviour of the minerals constituting each particle surface, relative to their total prop...
Turbulence is an important factor that affects flotation performance, which needs to be incorporated into flotation models. However, the measurement of turbulence in industrial flotation cells is difficult because of the highly abrasive and aggressive slurry environment. This has made the development and validation of models incorporating turbulenc...
Flotation is one of the most important primary separation processes in the minerals industry. As far as the mechanism of flotation is concerned, turbulence is one of the key parameters determining flotation performance because it affects three main processes: suspension of particles, air dispersion and particle-bubble collision, attachment and deta...
Measuring turbulence in an industrial flotation environment has long been problematic due to the opaque, aggressive, and abrasive three-phase environment in a flotation cell. One of the promising measurement techniques is electrical resistance tomography (ERT). By measuring the conductivity distribution across a measurement area, ERT has been adopt...
Turbulence and its distribution are of great importance in flotation processing and has been the subject of much research. However, there is no mature technique to measure turbulence in three phase (liquid–solid–gas) systems. In this research, the Piezoelectric Vibration Sensor (PVS) was developed, based on previous research, as a promising tool fo...
A regrind–flotation pre-treatment method developed to improve performance of a CIL circuit at copper–gold concentrators has been implemented at plant scale at the Newcrest Telfer mine. Low gold recovery in the CIL circuit due to the occlusion of gold by iron sulphide gangue minerals was overcome by the fine grinding of the CIL feed. A post-regrind...
Turbulence and its distribution are of great importance in flotation cell design as they affect suspension of particles, air dispersion and particle-bubble collision rates, which in turn determine flotation performance. However, there is no mature technique to measure turbulence in three phase (liquid-solid-gas) systems such as in flotation cells....
Process mineralogy' is a form of applied mineralogy which focuses on addressing problems associated with the processing of ores. 'Mineralogy' is the scientific study of minerals and 'mineral processing' is the production of concentrates from ores. 'Process mineralogy,' however can be defined as the practical study of minerals associated with the pr...
The detailed understanding of the variability in process performance parameters within an ore body forms a key aspect of ensuring that proper decisions are made with regards to the economic viability of that ore body. To gain this understanding, various tools have been developed over the years, of which the batch flotation test is the most well-kno...
Regrinding rougher flotation concentrates has become a common practice when processing low grade and complex ores. It not only reduces the particle size and improves mineral liberation but also modifies particle surfaces and pulp chemistry due to the strong electrochemical reactions taking place during regrinding. Therefore, the floatability of min...
This study evaluates the possibility of predicting colloidal and flow behaviour of kaolinite suspensions by measuring kaolinite crystallinity. The Hinckley index of different samples was calculated from XRD spectra as an indicator of the crystallinity. Kaolinite samples with a high Hinckley index showed a defined platy morphology with smooth surfac...
The effects of phyllosilicate minerals on the flotation performance and froth stability of a copper ore was investigated. It was found that various phyllosilicate minerals affect the copper recovery differently however they all caused the flotation grade to be reduced. The effect of different phyllosilicate minerals on the froth stability followed...
It is well known that froth phase has a controlling influence on the overall flotation performance. Froth recovery is expected to be affected by froth transportation behaviour. The latter has been represented by different volume balance and energy balance based models. In froth transportation models based on a volume balance, the froth phase is div...
Turbulence and its distribution are of great importance in flotation cell design as they affect suspension of particles, air dispersion and particle-bubble collision rates, which in turn determine flotation performance. However, there is no mature technique to measure turbulence in three phase (liquid-solid-gas) systems such as in flotation cells....
This study focused on the development of a new method, regrind-flotation pre-treatment, to improve the performance of the CIL (Carbon-in-Leach) circuit at copper-gold concentrators. Occlusion of gold by iron sulphide gangue minerals and the fine grain size of gold associated with them contribute to the low gold recovery in the CIL circuit. Fine gri...
With the increased exposure to progressively complex ores, there is growing concern over the effects of phyllosilicate gangue minerals. These minerals present challenges during ore beneficiation, with issues such as reduced flotation performance and complex tailings treatment arising. Often broadly classified as ‘clays’, the understanding of the di...
This study examined the performance of the CIL (Carbon-in-Leach) circuit at Telfer, a copper–gold plant treating porphyry copper deposits containing gold associated with both copper and iron sulphides, with an objective to identify factors normally limiting the gold recovery in the CIL circuit in the presence of a small amount of copper after coppe...
Geometallurgy aids the understanding of ore body variability but has the most value if the data is easily available along the entire mining value chain. This requires cross-discipline communication and collaboration across traditional silos, and an organizational culture that encourages that to flourish. Data that are collected by the numerous grou...
The increased exposure to low grade ores has highlighted the importance of understanding phyllosilicate gangue mineralogy. These minerals exist as common gangue minerals and have been shown to present challenges during ore beneficiation, with issues arising throughout the processing circuit. Nonetheless, the industry's understanding of the issues a...
Turbulence and its distribution are of great importance in flotation processing and has been the subject of much research. However, there is no mature technique to measure turbulence in three phase (liquid-solid-gas) systems. In this research, the Piezoelectric Vibration Sensor (PVS) was developed, based on previous research, as a promising tool fo...
Clay minerals are often associated with copper, gold and other valuable minerals and place a widespread problem in mineral flotation. This paper is one of a series addressing the problem caused by clay minerals in copper-gold flotation. This study seeks to understand the rheological behaviour of kaolinite and bentonite suspensions at natural pH and...
Key parameters for evaluating the hydrodynamic conditions within an operating flash flotation cell have been investigated. Profiles of the slurry at increasing depth within the cell have shown a strong trend of increasing slurry density (per cent solids) and coarseness (P80), with a clear indication of segregation on the basis of particle specific...
The characterisation of resources and description of variability across different ore domains is key to accurate prediction of probable metallurgical performance. Such characterisation testwork often has limited drill-core from which to work and this immediately confines the characterisation method to small-scale. For flotation feeds, the JKMSI (Mi...
Flash flotation cells are increasingly being employed to recover valuable material present in the grinding circuit, reducing the potential for over-grinding and enhancing plant performance with the added advantage of reduced capital outlay and operating costs. However it is not always possible to quantify the contribution of the flash to overall re...
Machine vision has been proposed as an ideal non-intrusive instrument to obtain meaningful information relating to the performance of the froth phase of flotation for the purposes of process control. Many attempts have been made to use machine vision to predict performance factors such as mass recovery rate and concentrate grade. These approaches h...
Much research has been performed on the effect of froth stability on flotation performance. Generally, stable froths result in high recoveries at low grade, and conversely, unstable froths result in low recoveries at higher grade. However, to manage the performance of a flotation cell using froth stability, a robust measure of froth stability is re...
In this work, the flotation of ultrafine pentlandite and its separation from lizardite in de-ionized water, and bore water of high ionic strength were studied. In de-ionized water, the flotation separation was poor due to low pentlandite recovery and high lizardite entrainment. However, bore water increased pentlandite flotation recovery while redu...
Flotation occurs as a result of bubble–particle attachment. This is controlled by the particle surface properties which are created by surface liberation of valuable minerals and collector adsorption within the chemical environment. This paper examines the contribution of both collector dosage and liberation of valuable minerals to bubble–particle...
Arsenic is a toxic and volatile element that has little commercial use. This is causing some concern to copper smelters as they are obliged to dispose of arsenic materials produced as a by-product to the smelting process in accordance with ever tightening environmental guidelines. The onus is to move back to concentrate producers to remove toxic el...
The reactivity of clay minerals and variety of these reactions are greater than any other known colloidal material. While it is acknowledged that clay minerals can cause problems in mineral flotation, the literature contains conflicting evidence, particularly with respect to the effect of clays on froth stability. It is well known that achieving an...
In this study, the effect of different regrinding conditions on the depression of fine pyrite at the cleaner stage was investigated. The regrinding condition was manipulated by different grinding media (stainless steel and mild steel). It was found that, after regrinding with mild steel grinding media, the flotation recovery of pyrite is much lower...
It has been proposed that blending of the Kennecott Utah Copper Corporation (KUCC) Bingham Canyon poorly-floating limestone skarn (LSN) ore with the monzonite ore (MZ), which in isolation floats well, results in a ‘poisoning’ effect on chalcopyrite, bornite and molybdenite flotation recovery. This proposition has been examined via a combined study...
Kennecott Utah Copper Concentrator processes ore from the Bingham Canyon porphyry copper deposit to produce copper and molybdenum concentrates in two circuits (bulk and molybdenum circuits). This deposit contains a number of ore types that are classified based on lithology and processing characteristics. The concentrator processes blends up to five...
The beneficial effect of electrolytes on mineral flotation has been observed and attributed to the improved bubble-particle attachment in a number of studies. However, the behavior of gangue minerals in electrolyte solutions has not been studied. In fine particle flotation, gangue minerals play an important role in determining both the recovery and...
The influence of mineralogy on flotation performance is examined at Newcrest’s Telfer operating in Western Australia. The flotation concentrator treats ore in two parallel trains. Each train has the same number and type of cells that are operated under similar conditions, including throughput, feed particle size distribution and gas profile, but tr...
The acid rock drainage index (ARDI) was developed to predict acid formation based on intact rock texture. Five textural parameters which have direct control on acid formation are evaluated. The ARDI forms part of the geochemistry–mineralogy–texture (GMT) approach to undertaking acid rock drainage (ARD) predictive tests. This staged-approach involve...
Flotation performance depends on bubble–particle attachment which is controlled by the particle surface properties which include the particle composition and the surface liberation of valuable minerals. This paper discusses the contribution of liberation of valuable minerals to bubble–particle attachment time measurements, under constant chemical c...
A critical aspect of geometallurgy is quantifying mineralogical and textural relationships that affect mineral processing (e.g., liberation and recovery) and it is vital that this information is included in the planning process for both mining and mineral processing. However, to date, this has been an expensive and time consuming venture and only m...
In batch flotation tests conducted on ores from the Merensky reef, changes in froth stability invariably occur with variations in the reagent suite. The main reagents are collectors (primary and secondary), activators, depressants and frothers. Since the particles entering and leaving the froth in a batch flotation system are continuously changing,...
Poly (N-isopropylacrylamide) (PNIPAM) is a temperature responsive polymer that undergoes changes from water soluble hydrophilic molecules to water insoluble hydrophobic colloids at temperatures below and above its lower critical solution temperature (LCST) of 32C. It has been comprehensively demonstrated that PNIPAM is an effective flocculant, caus...
Flotation of a low grade pentlandite ore containing large amounts of serpentine minerals from Western Australia was conducted with process water having high ionic strength. Nickel recovery was low in the flotation of both fine and coarse fractions. X-ray photoelectron spectroscopy (XPS) analysis indicated that oxidation occurred on both fine and co...
The non-stoichiometric sulphide pyrrhotite (Fe1-xS), common to many nickel ores, occurs in a variety of crystallographic forms and compositions. In order to manipulate its performance in nickel processing operations either to target the recovery or rejection or pyrrhotite, one needs an understanding of pyrrhotite mineralogy, reactivity and the effe...
A critical aspect of geometallurgy is quantifying mineralogical and textural relationships that affect mineral processing (eg, liberation and recovery). However, to date, this has been an expensive and time consuming venture and only minimal amounts of this type of data are typically available to be included in the mine planning process. Our resear...
The Merensky Reef at Northam Platinum Mine in South Africa is characterised by a high degree of variability with respect to reef elevation (difficult to mine), as well as mineralogy and texture (difficult to process). Development along strike and down dip of multiple reef types has led to unpredictable run-of-mine characteristics that pose problems...
The non-stoichiometric sulfide mineral pyrrhotite (Fe( 1-x)S), common to many nickel and platinum group element (PGE) ore deposits, occurs in varying crystallographic forms with the different types exhibiting subtly different physical and chemical properties. These differing properties are likely to influence the flotation performance of pyrrhotite...
Reagents play a vital role in determining the success of the flotation process and are one of the major running costs and sources of concern for industrial plants. However, due to the complexity of the process and the various interactions that occur it is very difficult to isolate the behaviour of each of the reagents, particularly on a plant scale...
The recovery of molybdenum at Kennecott Utah Copper (KUC) has become increasingly important as its demand and price have risen dramatically in the last few years. Consequently, the flotation behaviour of the molybdenum bearing mineral, molybdenite, has received a significant amount of attention. The flotation performance of molybdenite generally la...
The widespread use of organic depressants in sulphide flotation has remained restricted as they are still perceived to be non-selective and the adsorption mechanisms of these types of depressants are not clearly established. While it is generally accepted that natural polysaccharides interact with minerals via surface metal-hydroxylated species, de...
In the flotation of platinum bearing ores from the Merensky reef, which is carried out at pH 9, copper sulphate (CuSO4) is widely used as an activator. It is either added to the mill or to the first conditioner. Since lead ions can also be used as activators for sulphide minerals the aim of this paper is to investigate the flotation of a Merensky o...
