Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1652488
R. Bearman, D. J. Bowman, R. Dunne
ABSTRACT Upgrading coarse feed in gold plants, through a process of selective processing, has always been of interest. The level of interest has waxed and waned over the last 30–40 years, but improvements in methods and pressure to increase the efficiency of resource utilisation, have driven greater attention. The resources in question, not simply being the orebody itself, but the requirements for energy and water and the level of intensity applied. Despite various advances in technology, the market penetration of selective coarse upgrading, either via physical means (screening, DMS) or sensors (particle or mass sorting), is still limited. In relation to gold, uptake is complicated by low concentration and the lack of commercial sensors for direct detection. In this paper, the authors examine key factors impacting the rate and degree of uptake of preconcentration in the gold sector, as it relates to particle based particle sorting and DMS.
{"title":"Decision support for ore sorting and preconcentration in gold applications","authors":"R. Bearman, D. J. Bowman, R. Dunne","doi":"10.1080/25726641.2019.1652488","DOIUrl":"https://doi.org/10.1080/25726641.2019.1652488","url":null,"abstract":"ABSTRACT Upgrading coarse feed in gold plants, through a process of selective processing, has always been of interest. The level of interest has waxed and waned over the last 30–40 years, but improvements in methods and pressure to increase the efficiency of resource utilisation, have driven greater attention. The resources in question, not simply being the orebody itself, but the requirements for energy and water and the level of intensity applied. Despite various advances in technology, the market penetration of selective coarse upgrading, either via physical means (screening, DMS) or sensors (particle or mass sorting), is still limited. In relation to gold, uptake is complicated by low concentration and the lack of commercial sensors for direct detection. In this paper, the authors examine key factors impacting the rate and degree of uptake of preconcentration in the gold sector, as it relates to particle based particle sorting and DMS.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"12 - 23"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1652488","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47253434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1631633
T. Mahlangu, F. A. Sumaili, Dieudonne Ntamb Ayizi, B.M. Sindani, P. Mande, G. D. du Toit, Martijn Verster, S. Mogashoa, P. Lotz
ABSTRACT Kibali Gold Mine (KGM) processing plant treats both free milling and partially refractory ores. The flotation concentrate, is subjected to ultrafine grinding in 8 parallel FLS VXP 2500 ultrafine grinding (UFG) mills and undergoes a two stage preoxidation process at controlled pH of 10.2, prior to cyanidation. The primary objective of preoxidation is to reduce the reactivity of sulphide surfaces and thus reduce cyanide and oxygen demand downstream. Complex interactions amongst operational parameters of feed density, pH and dissolved oxygen concentration, complicates the circuit. This work demonstrates the impact of these interactions on gold dissolution and cyanide consumption. Aggressive preoxidation conditions have shown that the sulphide oxidation reactions not only increase temperatures but also generate cyanicides consistent with observed high cyanide consumption and poor dissolved oxygen concentration. From the extensive analysis of plant data and laboratory testwork, the plant has established and defined a niche operating domain for optimal preoxidation processes. This has been shown by the resultant drop in the sulphide concentrate residues from above 5 g/t at commissioning to below 3 g/t, currently achieved.
{"title":"Kibali Gold Mine sulphide concentrate treatment – understanding the preoxidation of sulphide concentrates","authors":"T. Mahlangu, F. A. Sumaili, Dieudonne Ntamb Ayizi, B.M. Sindani, P. Mande, G. D. du Toit, Martijn Verster, S. Mogashoa, P. Lotz","doi":"10.1080/25726641.2019.1631633","DOIUrl":"https://doi.org/10.1080/25726641.2019.1631633","url":null,"abstract":"ABSTRACT Kibali Gold Mine (KGM) processing plant treats both free milling and partially refractory ores. The flotation concentrate, is subjected to ultrafine grinding in 8 parallel FLS VXP 2500 ultrafine grinding (UFG) mills and undergoes a two stage preoxidation process at controlled pH of 10.2, prior to cyanidation. The primary objective of preoxidation is to reduce the reactivity of sulphide surfaces and thus reduce cyanide and oxygen demand downstream. Complex interactions amongst operational parameters of feed density, pH and dissolved oxygen concentration, complicates the circuit. This work demonstrates the impact of these interactions on gold dissolution and cyanide consumption. Aggressive preoxidation conditions have shown that the sulphide oxidation reactions not only increase temperatures but also generate cyanicides consistent with observed high cyanide consumption and poor dissolved oxygen concentration. From the extensive analysis of plant data and laboratory testwork, the plant has established and defined a niche operating domain for optimal preoxidation processes. This has been shown by the resultant drop in the sulphide concentrate residues from above 5 g/t at commissioning to below 3 g/t, currently achieved.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"74 - 86"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1631633","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43204672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1669982
N. Mkandawire, T. McGrath, A. Bax, J. Eksteen
ABSTRACT The dense media cyclone (DMC) has had wide application in beneficiation of coal, iron ore, diamonds and base metals, with limited applications in preconcentrating precious metals such as gold. This paper reports and discusses data from experimental evaluations of the DMC for preconcentrating gold ores. Two ore types were tested in the particle size range from 0.3 mm to 4.75 mm which was considered a pumpable size range. A DMC with a diameter of 100 mm was used to separate the gold ores at separation densities ranging from 2.55 g/cm³ to 2.95 g/cm³. Evaluation of the data confirms the potential of the DMC for gold ore preconcentration, with some ores being more amenable to gangue rejection than others. An optimum density of separation is required for a given type of ore in order to achieve balance between overall mass rejected and gold recovery.
{"title":"Potential of the dense media cyclone for gold ore preconcentration","authors":"N. Mkandawire, T. McGrath, A. Bax, J. Eksteen","doi":"10.1080/25726641.2019.1669982","DOIUrl":"https://doi.org/10.1080/25726641.2019.1669982","url":null,"abstract":"ABSTRACT The dense media cyclone (DMC) has had wide application in beneficiation of coal, iron ore, diamonds and base metals, with limited applications in preconcentrating precious metals such as gold. This paper reports and discusses data from experimental evaluations of the DMC for preconcentrating gold ores. Two ore types were tested in the particle size range from 0.3 mm to 4.75 mm which was considered a pumpable size range. A DMC with a diameter of 100 mm was used to separate the gold ores at separation densities ranging from 2.55 g/cm³ to 2.95 g/cm³. Evaluation of the data confirms the potential of the DMC for gold ore preconcentration, with some ores being more amenable to gangue rejection than others. An optimum density of separation is required for a given type of ore in order to achieve balance between overall mass rejected and gold recovery.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"87 - 95"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1669982","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46627464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1643133
S. Bacchuwar, N. Mkandawire, T. McGrath, C. L. Lin, J. Miller
ABSTRACT Specific gravity washability curves used in the coal industry to define the theoretical gravity separation efficiency can be used in the same way for evaluation of preconcentration operations in the metal mining industry. These theoretical metal recovery/gangue rejection curves, which establish the maximum in gravity separation efficiency, can be determined from three-demensional (3D) image analysis by high resolution X-ray microtomography (HRXMT) rather than by sink-float analysis using heavy liquid fractionation. In this way, the tedious, time-consuming, and toxic use of heavy liquids for laboratory sink-float analysis is avoided. In addition to the theoretical gravity separation efficiency curves by HRXMT, further 3D particle information on mineral composition and texture is obtained, including grain size distribution. Experimental HRXMT results for two sulfidic gold ores are presented and compared to the results from dense media cyclone experiments in order to evaluate the efficiency of gangue mineral rejection.
{"title":"X-Ray computed tomography for 3D analysis of gangue mineral rejection by gravity preconcentration of sulfidic gold ores","authors":"S. Bacchuwar, N. Mkandawire, T. McGrath, C. L. Lin, J. Miller","doi":"10.1080/25726641.2019.1643133","DOIUrl":"https://doi.org/10.1080/25726641.2019.1643133","url":null,"abstract":"ABSTRACT Specific gravity washability curves used in the coal industry to define the theoretical gravity separation efficiency can be used in the same way for evaluation of preconcentration operations in the metal mining industry. These theoretical metal recovery/gangue rejection curves, which establish the maximum in gravity separation efficiency, can be determined from three-demensional (3D) image analysis by high resolution X-ray microtomography (HRXMT) rather than by sink-float analysis using heavy liquid fractionation. In this way, the tedious, time-consuming, and toxic use of heavy liquids for laboratory sink-float analysis is avoided. In addition to the theoretical gravity separation efficiency curves by HRXMT, further 3D particle information on mineral composition and texture is obtained, including grain size distribution. Experimental HRXMT results for two sulfidic gold ores are presented and compared to the results from dense media cyclone experiments in order to evaluate the efficiency of gangue mineral rejection.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"49 - 63"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1643133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43725602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1702802
P. Bode, T. McGrath, J. Eksteen
ABSTRACT Enrichment and metal deportment metallurgical parameters, indicative of the propensity for a comminuted ore to preferentially concentrate metal into multiple density fractions during coarse particle gangue rejection (CPGR) by float–sink separation technique, were developed and applied. Including, a coarse separation enrichment deportment index (EDI) parameter metric to describe a comminuted ore overall preferential grade by density deportment response. The parameters describe the extent of gangue and value component liberation as a measurable rock property that is a function of both particle breakage regime and downstream separation technique. Ultimately the methodology provides metallurgical metrics for measuring the separation performance by the liberation of gangue in fine crushed comminuted ores. In this study, various laboratory-scale fine crushing mechanical and non-mechanical electric pulse SELFRAG Lab devices treated a Ballarat region gold ore to achieve a particle size of ≤2.00 mm to evaluate ore amenability for CPGR and preconcentration potential.
{"title":"Characterising the effect of different modes of particle breakage on coarse gangue rejection for an orogenic gold ore","authors":"P. Bode, T. McGrath, J. Eksteen","doi":"10.1080/25726641.2019.1702802","DOIUrl":"https://doi.org/10.1080/25726641.2019.1702802","url":null,"abstract":"ABSTRACT Enrichment and metal deportment metallurgical parameters, indicative of the propensity for a comminuted ore to preferentially concentrate metal into multiple density fractions during coarse particle gangue rejection (CPGR) by float–sink separation technique, were developed and applied. Including, a coarse separation enrichment deportment index (EDI) parameter metric to describe a comminuted ore overall preferential grade by density deportment response. The parameters describe the extent of gangue and value component liberation as a measurable rock property that is a function of both particle breakage regime and downstream separation technique. Ultimately the methodology provides metallurgical metrics for measuring the separation performance by the liberation of gangue in fine crushed comminuted ores. In this study, various laboratory-scale fine crushing mechanical and non-mechanical electric pulse SELFRAG Lab devices treated a Ballarat region gold ore to achieve a particle size of ≤2.00 mm to evaluate ore amenability for CPGR and preconcentration potential.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"35 - 48"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1702802","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43382074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1643131
A. Bax, G. Wardell-Johnson, W. Staunton
ABSTRACT One of the main problems in the design of carbon adsorption circuits for the processing of high silver gold ores is that the commonly used gold adsorption models are unable to replicate the frequently observed displacement of silver on carbon by gold in the first contactors of carbon-in-pulp/carbon-in-leach (CIP/CIL) trains operating with high metal loadings on carbon and high silver gold ratios. A model has been developed by Curtin University’s Gold Technology Group to simulate the competitive co-adsorption of gold and silver by activated carbon. The model utilises multi-component equilibrium isotherms and film-diffusion rate equations to describe the adsorption of gold and silver onto activated carbon. The model has been validated using laboratory and plant data. Case studies are presented to demonstrate the application of the model for the design of a greenfield project processing a gold/silver ore.
{"title":"Application of a co-adsorption model for the design of CIL/CIP circuits","authors":"A. Bax, G. Wardell-Johnson, W. Staunton","doi":"10.1080/25726641.2019.1643131","DOIUrl":"https://doi.org/10.1080/25726641.2019.1643131","url":null,"abstract":"ABSTRACT One of the main problems in the design of carbon adsorption circuits for the processing of high silver gold ores is that the commonly used gold adsorption models are unable to replicate the frequently observed displacement of silver on carbon by gold in the first contactors of carbon-in-pulp/carbon-in-leach (CIP/CIL) trains operating with high metal loadings on carbon and high silver gold ratios. A model has been developed by Curtin University’s Gold Technology Group to simulate the competitive co-adsorption of gold and silver by activated carbon. The model utilises multi-component equilibrium isotherms and film-diffusion rate equations to describe the adsorption of gold and silver onto activated carbon. The model has been validated using laboratory and plant data. Case studies are presented to demonstrate the application of the model for the design of a greenfield project processing a gold/silver ore.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"103 - 96"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1643131","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47305608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1658915
R. Asamoah, W. Skinner, J. Addai-Mensah
ABSTRACT This paper aims at investigating the gold leaching behaviour of refractory, bio-oxidized flotation gold concentrates, before and after high intensity milling, for enhancing gold extraction. Specifically, the role of factors such as milling time and ceramic balls-to-pulp mass ratio, coupled with corresponding physico-chemical changes on gold extraction yield and leaching kinetics was studied. From the results, high intensity milling of the bio-oxidised flotation concentrate reduced the average particle size by increasing the fraction of fines mainly through abrasion/attrition, and increased surface area by both fine particle and crevice production. Furthermore, notable increase in sodium cyanide consumption was observed with an increase in the mechanical stress deployed, consistent generally with degree of mineral relative amorphisation and reactive gangue mineral exposure. About 1.6–1.8 times variable increase in gold yield was observed after 24 h cyanide leaching of activated samples, irrespective of the impacted mechanical stress and degree of mineral amorphisation.
{"title":"Enhancing gold recovery from refractory bio-oxidised gold concentrates through high intensity milling","authors":"R. Asamoah, W. Skinner, J. Addai-Mensah","doi":"10.1080/25726641.2019.1658915","DOIUrl":"https://doi.org/10.1080/25726641.2019.1658915","url":null,"abstract":"ABSTRACT This paper aims at investigating the gold leaching behaviour of refractory, bio-oxidized flotation gold concentrates, before and after high intensity milling, for enhancing gold extraction. Specifically, the role of factors such as milling time and ceramic balls-to-pulp mass ratio, coupled with corresponding physico-chemical changes on gold extraction yield and leaching kinetics was studied. From the results, high intensity milling of the bio-oxidised flotation concentrate reduced the average particle size by increasing the fraction of fines mainly through abrasion/attrition, and increased surface area by both fine particle and crevice production. Furthermore, notable increase in sodium cyanide consumption was observed with an increase in the mechanical stress deployed, consistent generally with degree of mineral relative amorphisation and reactive gangue mineral exposure. About 1.6–1.8 times variable increase in gold yield was observed after 24 h cyanide leaching of activated samples, irrespective of the impacted mechanical stress and degree of mineral amorphisation.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"64 - 73"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1658915","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43071515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1631077
T. McGrath, A. Bax, J. Eksteen, J. McGrath
ABSTRACT Gangue rejection, resulting in an increased head grade at a higher net throughput (or, smaller plant footprint), and the creation of dual products, eg high grade and low grade, for alternative processing streams are two treatment options being investigated to turn otherwise uneconomic ores into reserves. Eleven gold ores have now been assessed for their potential for rejection of gangue by gravity separation using the gangue rejection amenability test (GRAT). The samples represent a variety of gold ore types, from several continents and gold producers. Additionally, two ores have been processed using four different crushing modes to characterise the influence of crush-type on liberation. The resulting GRAT database can be used for benchmarking and to determine the optimal gold loss vs mass rejected response for each ore given the influence of elemental deportment as a function of size and density based separation.
{"title":"Gangue rejection responses for a variety of gold ores","authors":"T. McGrath, A. Bax, J. Eksteen, J. McGrath","doi":"10.1080/25726641.2019.1631077","DOIUrl":"https://doi.org/10.1080/25726641.2019.1631077","url":null,"abstract":"ABSTRACT Gangue rejection, resulting in an increased head grade at a higher net throughput (or, smaller plant footprint), and the creation of dual products, eg high grade and low grade, for alternative processing streams are two treatment options being investigated to turn otherwise uneconomic ores into reserves. Eleven gold ores have now been assessed for their potential for rejection of gangue by gravity separation using the gangue rejection amenability test (GRAT). The samples represent a variety of gold ore types, from several continents and gold producers. Additionally, two ores have been processed using four different crushing modes to characterise the influence of crush-type on liberation. The resulting GRAT database can be used for benchmarking and to determine the optimal gold loss vs mass rejected response for each ore given the influence of elemental deportment as a function of size and density based separation.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"24 - 34"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1631077","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48875692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2019.1633506
P. Breuer, D. Hewitt
ABSTRACT Insights from a number of INCO cyanide destruction process reviews and studies are presented and discussed. In particular, the performance of three plants are discussed in terms of reagent (sulfite and oxygen) stoichiometry and utilisation, and the impact of process design, control, reagent addition points and slurry properties. Discussed also is the effectiveness of hydrogen peroxide use (supplementary oxygen source) in two of the plants reviewed. Oxygen mass transfer often limits the capacity of an INCO process. Hydrogen peroxide addition can improve the capacity, though process design improvements could provide a better economic outcome. Optimisation of the INCO process requires constant monitoring of feed and discharge weak acid dissociable cyanide concentrations and maintaining low but measurable dissolved oxygen in the reactor (e.g. 2–5 mg L−1). Changing solids properties over time requires adjustment to the sodium metabisulfate-to-weak acid dissociable cyanide weight ratio used for the destruction process control.
{"title":"INCO Cyanide destruction insights from plant reviews and laboratory evaluations","authors":"P. Breuer, D. Hewitt","doi":"10.1080/25726641.2019.1633506","DOIUrl":"https://doi.org/10.1080/25726641.2019.1633506","url":null,"abstract":"ABSTRACT Insights from a number of INCO cyanide destruction process reviews and studies are presented and discussed. In particular, the performance of three plants are discussed in terms of reagent (sulfite and oxygen) stoichiometry and utilisation, and the impact of process design, control, reagent addition points and slurry properties. Discussed also is the effectiveness of hydrogen peroxide use (supplementary oxygen source) in two of the plants reviewed. Oxygen mass transfer often limits the capacity of an INCO process. Hydrogen peroxide addition can improve the capacity, though process design improvements could provide a better economic outcome. Optimisation of the INCO process requires constant monitoring of feed and discharge weak acid dissociable cyanide concentrations and maintaining low but measurable dissolved oxygen in the reactor (e.g. 2–5 mg L−1). Changing solids properties over time requires adjustment to the sodium metabisulfate-to-weak acid dissociable cyanide weight ratio used for the destruction process control.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"104 - 113"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2019.1633506","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49198387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/25726641.2020.1725324
J. Coombes, T. Tran, A. Earl
ABSTRACT A mineral company’s resource models are a measure of its foundational assets that provide the basis for forward looking statements of corporate value and cash-flow estimates. Accuracy of the estimation process underpins corporate legitimacy. Importantly, local improvements in estimation process can translate into improvements in mine planning, and ultimately better-informed investment decisions. Traditionally, resource models use estimation parameters that are based on statistical patterns and spatial variability within a geologically informed volume constraint (‘the domain’). The variogram, block size analysis and determination of search parameters are assessed from the data within the geologically delineated domain. The set of parameters so determined are then applied to every estimation block within the domain, and the block model is then provided to the mine planner for optimisation. The mine planning optimisation process responds to each block grades. The focus of the mine planning process is to minimise ore loss and mining dilution and so provide the best possible opportunity for the orebody and its value to be realised. However, overly smooth grade models restrict a mine planner’s ability to achieve the best outcome for the project and for the asset owners. Despite the estimation of every block in a resource model being conducted independently of every other block in the model, Resource Geologists continue to generalise parameters across a domain of blocks. This paper challenges the global parameter approach, and instead seeks a more locally contextual set of parameters. This challenge is in keeping with innovations across industries and around the globe that seek real time bespoke responsiveness built on big data, machine learning and artificial intelligence. There are many steps ‘going local’ in estimation. This paper focusses on two aspects: firstly, optimising sample selection or search neighbourhood parameters (Local Kriging Neighbourhood Optimisation), and, secondly, addressing topcuts in response to those samples selected. A case study is presented to illustrate the process and demonstrate the improvements. The paper closes with a call for Resource Geologists to improve local as well as global accuracy of their resource models so that mine planners can respond to the knowledge and information available at a local scale in the grade estimation block model in their planning processes.
{"title":"Going local – innovating resource estimates to improve investment decisions","authors":"J. Coombes, T. Tran, A. Earl","doi":"10.1080/25726641.2020.1725324","DOIUrl":"https://doi.org/10.1080/25726641.2020.1725324","url":null,"abstract":"ABSTRACT A mineral company’s resource models are a measure of its foundational assets that provide the basis for forward looking statements of corporate value and cash-flow estimates. Accuracy of the estimation process underpins corporate legitimacy. Importantly, local improvements in estimation process can translate into improvements in mine planning, and ultimately better-informed investment decisions. Traditionally, resource models use estimation parameters that are based on statistical patterns and spatial variability within a geologically informed volume constraint (‘the domain’). The variogram, block size analysis and determination of search parameters are assessed from the data within the geologically delineated domain. The set of parameters so determined are then applied to every estimation block within the domain, and the block model is then provided to the mine planner for optimisation. The mine planning optimisation process responds to each block grades. The focus of the mine planning process is to minimise ore loss and mining dilution and so provide the best possible opportunity for the orebody and its value to be realised. However, overly smooth grade models restrict a mine planner’s ability to achieve the best outcome for the project and for the asset owners. Despite the estimation of every block in a resource model being conducted independently of every other block in the model, Resource Geologists continue to generalise parameters across a domain of blocks. This paper challenges the global parameter approach, and instead seeks a more locally contextual set of parameters. This challenge is in keeping with innovations across industries and around the globe that seek real time bespoke responsiveness built on big data, machine learning and artificial intelligence. There are many steps ‘going local’ in estimation. This paper focusses on two aspects: firstly, optimising sample selection or search neighbourhood parameters (Local Kriging Neighbourhood Optimisation), and, secondly, addressing topcuts in response to those samples selected. A case study is presented to illustrate the process and demonstrate the improvements. The paper closes with a call for Resource Geologists to improve local as well as global accuracy of their resource models so that mine planners can respond to the knowledge and information available at a local scale in the grade estimation block model in their planning processes.","PeriodicalId":43710,"journal":{"name":"Mineral Processing and Extractive Metallurgy-Transactions of the Institutions of Mining and Metallurgy","volume":"129 1","pages":"1 - 11"},"PeriodicalIF":1.2,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25726641.2020.1725324","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45484267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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