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By F H. Henrfquez, A G. Oroz

Design and operating conditions of large size mechanical flotation cells were evaluated by comparing them with actual operating conditions in a plant. The objective was to determine the time scale-up factor, typically based on empirical rules. Experiments were conducted on the rougher flotation circuit at Minera Escondida Ltd. The circuit consisted of self-aerated mechanical cells of 160 m3, arranged in six parallel banks with nine cells each. The rougher circuit flotation kinetics were evaluated from direct sampling and local mass balances around each cell of the bank. Adjusted overall mass balances were also developed. This information was used to fit different kinetic flotation models, and it was found that the rectangular distribution function was the most appropriate to describe the distributed rate constant for industrial operation. Then, a rougher flotation simulator was developed to describe the actual operation in terms of the operating variables (mass flowrate, solid percentage, feed grade) and the actual volumetric flowrate entering to each cell. In this study feed pulp samples were taken in parallel from the rougher circuit and were simultaneously floated in the laboratory. The kinetic behaviour was then modelled at a laboratory batch scale in order to determine the time scale-up factor between laboratory batch flotation data and industrial size flotation. The time scale-up factor observed for large sized cells, 160 m3, was found to be reasonably similar to those previously determined for self-aerated mechanical cells, but of lower size, operating at similar recoveries. In addition, the relative effect of mixing, between laboratory batch and an industrial flotation bank, was quantified by the parameter, separating the impact that kinetic and mixing changes have on the time scale-up factor. In general, the rougher flotation operation was found to reach the predicted metallurgical target, and the optimal separability criterion was also respected. The diagnostic generates information about the internal state of the process and helps to identify potential improvements for design, operation and control of the circuit.

Jan 1, 2005

By K Morrison

Australia’s ageing population means that by 2050 there will be 2.7 people of working age to support each Australian aged 65 years and over compared with five working people per retiree today and compared with 7.5 in 1970 (Swan, 2010). This means that there is going to be a greater demand on social services – for medical and aged care – from a smaller private income base. How will this gap be met? Australia is fortunate in that it has vast resources of mineral wealth; from iron ore, nickel and gas in Western Australia to the giant copper and uranium deposits at Olympic Dam in South Australia.The prospect of a meaningful profit based tax on this vast mineral wealth has been lost through Australian government’s handling of the issue in 2010 and with an industry fiercely opposed to the prospect of a mining tax. Hence, new ways of thinking are required. This paper looks at the issues facing the implementation of a novel scheme whereby Australia leases the mineral resources it extracts and thus derives income over the decades the metals are in-use in pipes, wires and structures with a premium paid for unreturned material or that used in dissipative applications. Applicable minerals could include copper, aluminium, nickel and rare earths. If Australia simply digs up and sells the metals once, the buyer becomes custodian of that resource and they benefit from controlling the future ‘above-ground’ resource stock.A complementary driver for a leasing scheme is the increasing importance of chain-of-custody following initiatives of the Responsible Jewellery Council with gold and diamonds, now with the potential to extend across commodities. The Australian minerals sector could thus position itself as a premium supplier with high social and environmental credentials.Recognising the implementation challenges, this paper includes a review of how such a system could be enforced to ensure that the metal is tracked throughout its life. It concludes with a discussion of the rates and terms should such agreements hold and suggestions for institutional arrangements for enforcing compliance.

Nov 22, 2011

By N Currey, G W. Wilson, P Ritchie

Kidston Gold Mine in Queensland, Australia has a 310 ha tailings impoundment that has undergone final closure rehabilitation. Kidston Gold Mine evaluated their closure options for this low acid generating tailings impoundment, and due to a lack of cover soils and the cost of importing material, the mine decided to investigate the possibility of direct vegetation onto the tailings impoundment surface. The mine subsequently embarked upon a well planned and detailed research program to determine the feasibility and sustainability of this closure option. The research program included vegetation trials, toxicology studies for metal uptake by vegetation, as well as a comprehensive closure water balance model for the tailings impoundment complex. This paper describes the results of the long-term closure water balance for the tailings impoundment complex for the pre-closure state of the impoundment, as well as predictions towards the impoundment performance once final rehabilitation of the tailings impoundment complex has been achieved. The water balance presented is unique in that it is founded on unsaturated flow principles and accounts in full the impacts of the surface flux boundary conditions. This novel approach enables the prediction of actual infiltration rates into the tailings impoundment surface, which in turn allows for the calculation of how much seepage will exit from the tailings dam toe drains.

Jan 1, 2003

By B Maybee

In underground mine planning, many potentially value-eroding decisions are made due to a lack of time and proper evaluation practices. The information required for mine planning decisions goes beyond external sources of uncertainty that are recognised by typical evaluation techniques used in the mining industry, to include technical factors (eg mine development layout) and the ability of a mineral extraction project to achieve its anticipated production levels. Due to the individual characteristics that define underground mining projects, each will exhibit a different risk profile, and thus advanced optimisation and evaluation techniques are required to capture this information.As underground mine planning tools become more sophisticated, mine planners have the capacity to investigate numerous mine sequencing options to identify the best strategy for a given project, creating higher value for shareholders. This paper describes a risk-based evaluation methodology (RbEM) that accounts for financial and technical risk in the evaluation of underground mining projects. While the use of the RbEM has been described in previous works, no benchmarking of the benefits that can be realised from a change in those decisions that are made early in the process has been undertaken. To show the benefits that can be achieved from using the RbEM, this paper updates a case study to which the RbEM was applied, and takes a retrospective look at whether additional value would have been gained by following the strategic recommendation of the RbEM versus a typical optimisation exercise that aims to maximise the net present value.CITATION:Maybee, B, 2012. Can a risk-based evaluation provide a more valuable mine design?, in Proceedings Project Evaluation 2012 , pp 53-58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By A J. Cornah

"The mine geologist’s role in classifying ore from waste during grade control represents a critical link in the mining value chain. Any improvement in the ore/waste selection success rate (thus reduction in misclassification) which can be delivered by the mine geologist represents a value proposition. Improvement achieved without additional operating cost (for example extra drilling and sampling) will directly and immediately add value to the mining operation and therefore clearly must be pursued. Such improvement may be leveraged from existing resource drilling data which are typically less numerous but better quality than the grade control data. They are usually excluded from grade control estimates (termed the ‘base case’ approach here) because of the differences in quality.Various specialised geostatistical tools are available to account for differences in precision and accuracy between data sources during spatial estimation. This paper uses a conditional simulation (CS) case study to assess the benefit of integrating resource data into grade control estimates through ordinary kriging (OK) of pooled data sets, cokriging (CK), and ordinary kriging with variance of measurement error (OKVME) when the grade control data are:unbiased but increasingly imprecisebiased and increasingly imprecise. The premise assumed is that the resource data are unbiased and precise.The paper demonstrates that, if appropriately handled, resource data may be used to improve grade control estimates and thus improve ore/waste selection success without additional operating cost. Where grade control data are imprecise but unbiased it is recommended to integrate resource data using OKVME. This re-appropriates kriging weights from less precise to more precise data locations and improves the grade control estimation precision compared to the base case; it consequently provides an improvement in the grade control selection success rate. If grade control data are associated with significant bias, integration through CK is recommended as the biased data are zero sum weighted. CK consequently provides an unbiased estimate with some improvement in estimation precision compared to the base case and consequently improvement in the ore/waste selection success rate.CITATION:Cornah, A J, 2014. Incremental improvement of grade control models using resource data, in Proceedings Ninth International Mining Geology Conference 2014 , pp 387–396 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By Yianatos J. B

The advances in the study of control alternatives for flotation columns are reviewed. An integral solution to the control problem has to deal with problems associated with instrumentation, process modelling, control strategies and control algorithms. The term hierarchical control is used here to mean the intelligent integration of available knowledge, control algorithms and logic rules of decision. The selection of information, algorithms and rules is based on the experimental and theoretical knowledge of the column flotation process. The software support was designed and implemented in object oriented computer programs. This technique allowed the implementation of a combination of control techniques, algorithmics and heuristics, in the form of a control strategy. This strategy has shown to fit well with processes exhibiting complex dynamic characteristics. The hierarchical control was implemented in a pilot column and included the following general aspects: co-ordination of distributed conventional control loops, use of sets of control parameters for the froth depth control loop according to the froth depth state, verification and diagnosis of sensors, on-line predictive estimation of gas hold-up, diagnosis of common operating problems and the use of predictive control to account for feed flowrate changes.

Jan 1, 1995

By P D. Munro

"This is a reprise of the paper ‘Back to the Future – Why Change Doesn’t Necessarily Mean Progress’ presented to the Tenth Mill Operators’ Conference in 2009. It was observed that the ‘boom and bust’ cycles of the industry, together with trends in tertiary education and the effects of fly-in fly-out (FIFO) operations raised serious questions about the sustainability of human capital in the mineral processing sector.In 2016 we find ourselves in a ‘bust’ after enjoying a decade of the longest commodity price ‘boom’ in a century. In the ‘boom’ did we:make any technological breakthroughs?put measures in place to improve our human capital, especially in the area of ‘professional formation’?The paper makes observations on the current performance of mineral processing engineers and the organisational milieu in which they operate. It questions whether mineral processing engineers are actually ‘adding value’ at some sites given their organisational and operational practices.Some technical trends are examined and what it might mean for mineral processing engineers.Given the above and demographic trends for mineral industry professionals, changes to the seemingly current laissez-faire model of professional development are proposed.Citation:Munro, P D, 2016. Back to the Future - Still on the Dark Side, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 341–348 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By N Setoudeh, A Nosrati, N J. Welham

The current surge of interest in lithium (Li) is due to the anticipated demand for electric vehicles and small scale power storage. Brine deposits contain most of the global Li resource, however hard rock deposits can be more readily and rapidly developed and comprise the majority of proposed projects. These projects plan to use the conventional processing routes of dense medium separation and / or flotation to produce a spodumene concentrate for sale. The standard route for subsequent processing of spodumene concentrate is thermal decrepitation, acid leaching, solution purification and precipitation of lithium carbonate. This is typically followed by further purification. A number of projects have ores which contain other lithium minerals, principally micas, lepidolite and zinnwaldite, necessitating an alternative treatment route. Several different routes for spodumene processing are under development to reduce costs to compete with brine projects. This paper will give an overview of the strengths and weaknesses of the current and alternative processes.CITATION:Welham, N J, Nosrati, A and Setoudeh, N, 2017. Lithium ore processing – an overview of the current and new processes, in Proceedings MetPlant 2017, pp 185–194 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By P Woodward, T Ly, N Muhamad

OZ Minerals' Prominent Hill copper-gold concentrator is located 650 km north-west of Adelaide in the Gawler Craton of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a design capacity of 8 Mtpa. The flotation circuit includes six rougher cells, an IsaMill for regrinding the rougher concentrate and a Jameson cell preceding the three stage conventional cell cleaner circuit.Since its commissioning, the Prominent Hill flotation circuit has been the focus of a series of projects aimed at continual performance improvement. This has been achieved by a systematic approach of project identification, evaluation and implementation which has led to a progressive improvement in flotation performance. Innovations that have been successfully implemented include aspects of cell design and operation, and reagent suite optimisation.Improvements to the mechanical cells initially focused on the installation of a modified rotor-stator design in the rougher circuit, as recommended by Outotec. Isolated cells were fitted with this technology and proven to provide a benefit for copper recovery before the design was trialled in subsequent cells along the bank. Based on this success, further modifications were made to other aspects of the rougher and cleaner cells.Laboratory trials conducted at Prominent Hill involve a screening process identifying potential reagents from a list of products, which are then rigorously tested in the laboratory before one is selected for trial in the concentrator. Where these reagents have demonstrated a statistical improvement in performance they have typically been incorporated permanently into the flotation circuit. This paper discusses the process of continual improvement at the Prominent Hill flotation circuit and the optimisation achieved by the implementation of key initiatives.CITATION:Woodward, P, Muhamad, N and Ly, T, 2013. Optimisation of the Prominent Hill flotation circuit, in Proceedings MetPlant 2013 , pp 431-444 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By D Roughsedge, J van der Sandt, L van den Berg

Axial flow fans are commonly used as auxiliary fans in underground mines to supply air to development headings. As diesel dilution requirements increase the fans used in conjunction with ventilation bags are becoming larger in diameter to move greater quantities of air over greater development distances. It is not uncommon for mining operations to sometimes use a number of these larger auxiliary fans with high airflow capacity in parallel as primary fans for the operations. These primary fan stations are often considered temporary installations and the fan selection and fan station design is rarely optimised. These temporary installations may become permanent resulting in an inefficient or unreliable primary ventilation system. A recent study looked at the likely causes of multiple primary fan failures at one operation with axial fans installed as primary units where the fan selection and fan station aerodynamic design was far from optimal. This paper explores some of the typical mechanisms of failure such as high pressure stall, unbalanced airflow, and fan tip speed as well as fabrication material. The paper proposes a number of good practise principles that should be considered during the design of a fan station. A second topic covered is the advantages and disadvantages of using different types of fans such as axial, mixed flow and centrifugal units. Here the concept of fan specific speed and its relevance to fan selection is discussed. Finally the paper quantifies the effect of using a high pressure auxiliary fan as a primary fan in a low pressure circuit, which may increase the mineÆs operation cost.CITATION:van der Sandt, J, van den Berg, L and Roughsedge, D, 2013. Practical considerations when using auxiliary axial flow fans as a primary mine fan, in Proceedings The Australian Mine Ventilation Conference , pp 63-70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By B N. Noller, J C. Ng, S L. Bruce

Mining activities can result in the transfer of harmful elements, including arsenic and lead, into the environment. In Australia, one of the potential future uses of rehabilitated mine land is to stock grazing animals. Elemental uptake is dependent on bioavailable fraction for adsorption upon exposure. Bioavailability data are generally lacking in order to provide realistic health risk assessments relating to harmful elements from mine tailings in Australian conditions. Another key component of risk assessment is the ability to estimate a realistic exposure, or dose rate, of the tailings to the grazing cattle over a set period of time. Hence, we aimed to conduct grazing trials directly on rehabilitated tailings facilities in order to provide valuable in situ information on heavy metal dose rates and associated accumulation. For the laboratory-based evaluation of comparative bioavailability, groups of cattle were fed five days a week on a normal diet spiked with mine tailings or soluble pure salts of target elements (eg sodium arsenate, sodium arsenite and lead acetate) for about eight months. For the field validation, cattle were allowed to graze directly on rehabilitated tailings facilities over a similar length of time. Blood and a biopsy of the muscle and liver were periodically collected to monitor arsenic accumulation. At necropsy, blood, muscle, liver, kidney and other saleable tissues were measured for arsenic concentrations. Although this study was focused on arsenic, lead and other metals were also measured. Predictive models for arsenic and other metals have been established to calculate the maximum grazing duration without the risk of exceeding specific food safety guidelines. The outcome of this study is a predictive model for maximum beneficial use of certain rehabilitated tailings for cattle grazing where grazing activities do not impact on the integrity of the tailings dams.CITATION:Ng, J C, Noller, B N and Bruce, S L, 2014. A predictive model for beneficial use of rehabilitated mine tailings for grazing cattle after mine closure, in Proceedings Life-of-Mine 2014 , pp 563–572 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By D Brown, K Markovic, Z Tabor

From ancient times to the modern world, the mining industry has played a pivotal role in shaping the society that we live in today. It remains an integral part of everyday life and is a catalyst for both technological and economic growth. With finite resources on Earth, and growing pressures surrounding climate change and the environment, space mining opportunities have become of increasing interest. Recent discoveries have shown celestial bodies including the Moon and surrounding asteroids, contain an abundance of critical minerals, as well as resources necessary to sustain human life. These discoveries coupled with a transition into the digital and autonomous age, offer an innovative solution to solving some of the mining challenges currently being faced on Earth. Similarly, they also offer a pathway to enabling deep space exploration and off Earth exploratory missions. However, like with mining operations on Earth, space remains and immensely challenging and complex operational environment. The inhospitable nature of space poses new challenges, including communication barriers, lunar dust, cosmic radiation, and gravity. The challenges and risks are not just technological, as Environmental, Social, and Governance (ESG) factors must also be considered to prevent unintended consequences and hazards. Furthermore, future workforce, law, financial, and security systems must evolve to enable space mining to take place. These are all known aspects to begin with, but as the complexity of the space grows it becomes apparent that a holistic approach to assess and manage these factors will be required.

Sep 1, 2024

By A E. Waltho, W J. Shaw

Predicting the physical characteristics of various ore types has for long been a difficult problem during mining. Grade control practices tend to concentrate on the chemical grade of the ore. Estimation of physical characteristics such as beneficiation behaviour is commonly limited to the simplistic application of historical averages. Large amounts of geochemical data are often gathered during the exploration and mining stages of a project, especially in ferrous and base metal deposits. In addition to the elements of principal economic interest, samples are often analysed for suites of gangue constituents to determine whether the mineralisation lies within target specifications. This multi-element data is often put to no other use than this simple chemical classification, yet it may present the geologist or metallurgist with valuable insights into the mineral content and physical characteristics of the deposit. Normative mineral estimates have been used as a method for characterising igneous rocks for almost 100 years. The method establishes and applies a set of sequential rules, by which the chemical components of a sample are assigned to mineral components. Provided that it is possible to make some realistic assumptions about the mineral species likely to be present in a rock unit or deposit and their paragenesis, this approach can be extended to a variety of mineral deposits. The geochemical data that are routinely collected when, for example, drilling iron ore and base metal deposits, can be used to derive estimates of normative mineral content. These estimates can be used to characterise physical or metallurgical aspects of the ore, such as density, beneficiation behaviour and metal recovery. This paper examines the application of normative mineral estimates to a variety of practical resource characterisation problems. The potential for predicting the lump and fines proportions of iron and manganese ores is also discussed.

Jan 1, 1999

THIS paper is the outcome of experiments carried on and experience gained. at the Waihi-Paeroa Gold Extraction Company's tailings plant at Waihi, New Zealand. The plant was erected to treat accumulated tailings which had been discharged into the Chinemuri River by the Waihi batteries.The Chinemuri River is a common sludge channel for all mining debris, tailings, and ashes from the power plants, the last being the cause of occasional high residues, which gave so much trouble to the management. The tailings were dredged from the bed of the river into barges by means of a Pohle air lift, the power being supplied: by a 13 b.h.p. Tangye oil engine driving an air compressor and a centrifugal pump. The sands were elevated from the barges by bucket-belt elevators over screens, to eliminate large particles and rubbish, into storage hoppers, and from there fed direct into four C. Judd Ltd. tube mills.The method of treatment was fine grinding in a weak cyanide solution, agitation in B. and M. tanks, filtration with turn-over vacuum filters, and precipitation with zinc shavings. The comparatively high values of the residues in gold gave a great deal of trouble, 'and it was not until repeated experiments were carried out that the cause of the trouble was located. While the value of silver residues remained stationary, the gold values...

Jan 1, 1912

By H Cifuentes, D J. Williams

Despite the recognised importance of tailings management, there remain little data on the potential benefits of biological treatments compared with physical and chemical treatments. The operation of the majority of tailings storage facilities (TSFs) continues to employ mainly physical solutions, such as sub-aerial tailings slurry deposition, with increasing adoption of thickening, paste and filtration to dewater the tailings involving the addition of chemicals such as flocculants and coagulants. However, with tailings production continuing to escalate rapidly due to the increasing demand for commodities and reducing ore grades, available technologies have not demonstrated cost-effective performance at high tailings production rates. This paper examines the emerging role of bacteria to better manage tailings, reducing risks and optimising storage capacity. Bacteria have the potential to enhance tailings dewatering, maintain their permeability, delay the onset of desiccation cracking, and improve their shear strength. Bacteria-treated tailings may be suitable for use as construction materials. Bacteria also have potential in limiting the dusting of tailings and facilitating rehabilitation on closure. The paper describes a series of laboratory involving the addition of harmless bacteria to a range of tailings. The bacteria form a compact material called calcite (a common and stable form of calcium carbonate), which immobilises the tailings particles, releases water, and cements the tailings in a stable and natural matrix. The water released can be recovered or evaporated, depending on site objectives. The bacterial reactions are linked to physical and chemical processes, providing the potential for an optimal mix of technologies for particular tailings and site conditions.CITATION:Cifuentes, H and Williams, D J, 2018. Potential improvement of tailings geotechnical behaviour using bacteria, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 228–238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

This paper summarises the current status of the mining sector in Poland in terms of vertical transport system safety. Selected results of research programs conducted at the AGH-UST relating to mine hoist system safety are reviewed. The conclusions support the notion that the costs of vertical transport systems can be reduced, while at the same time maintaining the required safety and reliability levels. Novel solutions: movable fender beams HWR, linings modar« and the integrated shock absorbers PHH for conveyance guiding systems fully confirm this hypothesis.

Jan 1, 2005

By S J. Neethling and, S J. R Simons

In this paper the effect of humic substances (natural surfactants), electrolytes and solid particles on bubble coalescence, and as a consequence on froth stability, have been investigated. In this study two bubbles of equal size were formed and forced to collide using a novel experimental apparatus. The interactions were recorded by a high-speed camera, the images of which helped to determine the coalescence frequency and the coalescence time, as well as the mechanisms of the interactions. Two types of humic substances were used, along with three different electrolytes. Humic substances appeared to have a considerable effect on bubble coalescence, while the effect of electrolytes was minimal. Moderate and high hydrophobic glass spheres were used between two bubbles. Very hydrophobic spheres promoted fast bubble coalescence, while moderate hydrophobic spheres had no effect. Data of coalescence frequency and time is presented, as well as images of the coalescence events. The coalescence frequency was used to validate a parameter, Pf, known as the film failure frequency, used in a simulation model to predict foam height in a gas-sparged vessel. Predictions determined using Pf were then validated by experimentation.

Jan 1, 2005

By S Gulati, N Sarkar, T Vink, S Battersby, L Okada

This paper examines a successful project implemented by BHP Mitsubishi Alliance (BMA) and the Polymathian team at Deswik, aimed at enhancing short-term scheduling processes to reduce vessel turn times in the BMA Central Queensland coal value chain. The project’s objective was to digitalise the planning process to enable planners to make data-driven insights to improve the profitability of the value chain. The strategy involved developing a digital mining system that incorporates data storage, cloud computing, and the ability to meet the integration needs of both internal and external business systems. This was complemented by a sophisticated, optimisation-based, decision-support tool to enhance the planning teams’ ability to make timely and effective decisions.

Sep 1, 2024

By Y B. Kang, Y J. Park

Ti-added ultra-low carbon (ULC) steel is produced by adding Al and Ti during the secondary refining process to deoxidise molten steel and to bind C and N which are detrimental to the deep drawing quality of the steel product. However, the production of Ti-added ULC steel faces challenges, including submerged entry nozzle clogging and surface defects on cold rolled coils. The troubles were often attributed to ‘Al-Ti complex inclusions’ in the molten steel. However, the evolution of oxide inclusions including their stability has been still unclear. In the present study, the evolution of these inclusions in Ti-added ULC steel was investigated by phase diagram measurement, CALPHAD thermodynamic modelling, high-temperature stability test for the oxides, and observation of transient behaviour of oxide inclusions in the steel. The phase diagram of the Al-Ti-O system was elucidated with an emphasis on oxygen potential, which significantly controls the stability of the oxides. CALPHAD thermodynamic models and a self-consistent database were developed. The transient behaviour of Al-Ti complex inclusions in Ti-added ULC steel was observed in situ using a confocal scanning laser microscope. This was additionally validated by the new thermodynamic model. The equilibrium phases of the oxide inclusions were investigated using a high-temperature resistance furnace, and were analysed using a secondary electron microscope, energy dispersive spectrometer, and electron back-scattered diffraction. By considering the morphology and crystal structure of these inclusions, the evolution of Al-Ti oxide inclusions was elucidated. Various behaviour of Al-Ti inclusions and their influence on steel cleanliness are discussed.

Aug 21, 2024

By H Kurth

Mining geologists utilise many technologies to map, sample, measure, model and plan before and during the mining process. Predicted ore quality rarely corresponds with feed quality determined by process operators. Objectively measuring conveyed material quality accurately in real time avoids disagreements over mined ore quality and generates opportunities to improve mill feed quality.This paper discusses the well proven PGNAA (prompt gamma neutron activation analysis) technology used in the GEOSCAN-M elemental analyser that is ideally suited to measuring composition of primary crushed conveyed material in real time. Representative, continuous, fully penetrative measurements are unaffected by particle size, belt speed, mineralogy, dust or layering on the conveyor. Material can be directed to processes or stockpiles by utilising measurement increments of typically one to five minutes and then activating diverters to direct increments to the correct location. Waste, low-grade or deleterious material can be rejected to waste dumps or stockpiled for later processing. Material meeting a product specification can bypass unnecessary processing. Paybacks in weeks have been achieved for such applications. Process operators are able to control the blend of ores fed into the mill to improve processing performance and use measurements for ore reconciliation and metal accounting. Utilising the technology to upgrade ore quality after mining and before processing is beneficial in improving plant economics.The technology has been successfully utilised in base metals, ferrous metals and industrial minerals. Mining geologists can determine ore quality being produced in real time and modify the ore quality prior to milling. Ore feed quality measurements are also used by process operators in optimising plant performance. The elemental content can help identify geometallurgical domains as well as other major changes in quality, which may affect processing. This paper outlines proven applications and case studies and proposes some innovative applications.CITATION:Kurth, H, 2017. Measuring ore quality using real-time on-belt elemental analysis – more than grade control, in Proceedings Tenth International Mining Geology Conference 2017, pp 213–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017