Search Documents

By Alan Bye, Nick Beaton, Wayne Stange, Emmy Manlapig, James Groutsch

"For over 50 years the JKMRC has applied a unique education-based research strategy to develop modelling and simulation tools that are "fit for purpose" for industrial application. These tools are widely used for the analysis and optimisation of mining and mineral processing systems. As the mining industry context evolves to deal with declining head grades, falling commodity prices, professional skill shortages, and an exponential growth in the volume of data, a re-evaluation of what "fit for purpose" means in the future is required. It is contended that future industry needs for simulation-based decision support requires tools and systems that incorporate: • Multi-component modelling, • Models of complex sensor behaviour, • Integration across the physical value-chain e.g. resource to market, • Financial analysis including risk and uncertainty assessment, • Enabling multi-criterion decision making (technical, financial and environmental), • Ore-body knowledge at multiple scales, • The use of fundamental numerical models to provide insight for the development of practically useful models, and • Decision support delivered through remote operations centres. JKMRC and CRC-ORE are collaborating to develop a next-generation simulation-based decision support system that assists in addressing these challenges. The Integrated Extraction Simulator (IES) combines many years of pragmatic and successful work integrated with modern technology trends - in particular the rapid move to cloud-based computing."

Jan 1, 2014

By Bern Klein, Givemore Sakuhuni, Libin Tong

The use of continuous discharge centrifugal concentrators introduced in the early 1990’s for recovery of gold associated with sulphides has introduced a novel application niche for gravity concentration which could not be realized with the low mass yield batch and semi-continuous concentrators. A typical application is scavenging gold associated with sulphides from flotation tails which has potential to increase productivity by reducing gold loss to tailings and lower grinding cost by using a coarser grind. However, the full potential of this technology has not been fully exploited partly due to the lack of reliable small sample procedures to demonstrate applicability. This paper introduces a bench-scale procedure developed to characterize the Knelson Continuous Variable Discharge concentrator (CVD) for scavenging gold from flotation tails. The procedure code named gravity release analysis was derived from standard flotation release analysis. It is a modification of the gravity recoverable gold and gravity amenability test in order to best simulate continuous centrifugal concentration. Based on this iterative procedure, a gravity release index similar to the flotation rate constant, for measuring individual mineral gravity susceptibility for an ore is introduced which can be a useful quantitative measure to both predict application of centrifugal concentration and for plant design. The gravity release analysis procedure was tested on a polymetallic flotation plant tailing at Myra Falls, BC, Canada and results show that it can predict CVD performance. The gravity release index for gold was observed to decrease with each successive cleaner stage showing that the initial stages recover liberated gold whilst successive runs recover gold associated with sulphides and or gangue. The difference in magnitude of the gravity release index for different mineral species shows the species separable by centrifugal concentration.

Jan 1, 2014

By A. S. Broesder

"With depletion of global ore deposits, there has been an increasing industry trend towards mining of lower average grade deposits in order to meet global demand, resulting in increased processing cost, energy usage and water usage. Consequently the industry is seeking pre-concentration technologies to reduce costs, increase production in existing operations and potentially enable the economic mining of previously uneconomical deposits. This pre-concentration can also advantage downstream processing and metal recovery. CSIRO has developed a large scale magnetic resonance based technology for the rapid quantitative detection of selected copper, iron and arsenic minerals in bulk ore. The technology is suited to measurement on large primary conveyors for enabling “pod” based sorting. The approach used in high tonnage sorting is to not sense and divert individual rocks, but to instead measure groups of rocks (“pods”) carried continuously on a single primary conveyor that can be diverted by conventional mechanical means. Bulk ore sorting operates by removing barren ore pods from a stream of crushed ore based on a bulk sensor measurement at a pod resolution of ~1 – 10 tonnes. The sorting process is based on the intrinsic variability of grade during the mining process that often occurs at the few tonne scale, and for instance, is common in many porphyry copper deposits. The MR technology has been proven in the laboratory for a wide range of copper, arsenic and iron minerals. A full scale prototype sensing system has been demonstrated in a trial at an Australian copper mine. Implementation trials of commercial MR based bulk sorting systems are progressing during 2018.INTRODUCTION An increasing trend in the mining industry is the exploitation of larger lower-grade deposits to meet global demand. Low-grade deposits involve increased processing cost, energy and water usage and increased tailings. There is therefore growing interest in technologies that enable more efficient extraction of low grade deposits. Water intensity of mining activities in a context of water scarcity, and the environmental and health implications of mine tailings are existing challenges, which are only made worse by the progression to lower grade orebodies. There is therefore also an interest in safer, cleaner and less wasteful extraction and production to ensure community well-being and environmental resilience."

Jan 1, 2018

By C. Abbruzzese, F. Vegliò, S. Ubaldini, R. Massidda

"Gold solubilised during cyanidation can be recovered by precipitation (Merrill-Crow process) or by adsorption onto activated carbon, these being the techniques applied in industrial plants.Precious metals (Au, Ag) adsorbed onto activated carbon are extracted during a subsequent stage in aqueous phase, by various technologies, such as hot elution (70-80°C) or under pression desorption (100-130°), with hydro-alcoholic solutions.This stage is of great interest from an economic point of view, due to the high energy costs. Temperature represents the critical kinetic factor.The aim of this paper was to study the influence of different water/organic solvent mixtures (isopropyl alcohol, ethanol and ethylene glycol) on the desorption process.The experimental work was carried out on laboratory scale, using activated coconut carbon with different temperatures and extraction times, without adding cyanide.Best results have been obtained in this order: isopropyl alcohol > ethylene glycol > ethanol. Starting from gold concentration of about 5 g Au per kg of carbon, best kinetics resulted in 97-100% of gold extraction, after 8 hours of desorption, at a temperature of 80ºC."

Jan 1, 2003

"The business importance of water for mining companies is unequivocal as it may affect several aspects of mining projects ranging from the life-and-death license to operate to the imperative economic viability. It is thus no wonder that nearly all mining companies acknowledge water-related risks, issues and opportunities in their respective sustainability report. Somehow, this procedure has fostered the idea that water frugality could be the sustainable solution to several water-related issues. The regular exercise of water accounting should then follow as a key strategic requirement. Water accounting is defined as the application of a consistent and structured approach to identifying, measuring, recording and reporting information about water. However, several factors discussed herein have led to the fact that some water accounts are still produced using means (hardware and software) which undermatch the value actually associated with water. The resulting fuzziness about water usage could result in missed opportunities, suboptimal operations or even lead to environmental law violations. This paper subscribes to the distinctive perspective that, once underlying concepts and practical definitions have been standardized under a supported framework, such as the openly available Water Accounting Framework (WAF) published by the Minerals Council of Australia, most of the remaining water accounting issues may be boiled down to accuracy issues and, ultimately, to how much accuracy is valued by the stakeholders. Using the latest WAF document as a baseline for best practices of water accounting and, borrowing concepts from the fields of sensor network design in the process industries and best practices of metal accounting, this paper reviews some essential accuracy issues to be considered when designing or analyzing water accounting systems in mineral processing. The current paper also includes some elements for a promising attempt to include the value of information paradigm inside the water accounting best practices."

Jan 1, 2014

By M. A. Hampton

The surface oxidation of sulfide minerals in aqueous solutions is an important sub-process in sulfide flotation and hydrometallurgy, but a full understanding of the oxidation process and products is still lacking. Many oxidation pathways and products involving elemental sulfur, metal polysulfide, metal-deficient sulfide and sulfate have been proposed, confirmed and argued. In this paper we provide further insight into the surface electrochemical behaviour of galena in aqueous solutions. For this research we have developed a novel experimental system, that combines chronoamperometry and AC-mode AFM surface imaging, which allows for in-situ, synchronized electrochemical control and examination of oxidative surface morphology. At pH4, the morphology of elemental sulfur (detected by ex-situ Cryo-XPS) formed on the oxidizing galena surface depends on the electrochemical potential pathway. In multi-step chronoamperometry (i.e. four potential steps from 0 mV to + 350 mV) the sulfur forms as nanoscopic domains, whereas in single-step chronoamperometry (i.e. one potential step from 0 mV to + 350 mV) sulfur forms as a heterogeneous layer. In each case the oxidation is controlled so that the number of electrons (coulombs) passed per unit area is the same, therefore the amount of sulfur produced is also the same. The differences in morphology with electrochemical potential pathway are explained using a nucleation and growth model. The formation of sulfur on the surface increased both advancing and receding contact angle of galena, but the morphological changes induced by different electrochemical potential pathways did not significantly alter the hydrophobicity of the surface. Keywords: galena, lead sulfide, oxidation, Atomic Force Microscopy, electrochemistry, collectorless flotation, hydrophobic

Sep 1, 2012