Bern Klein

Professor

Relevant Degree Programs

 

Graduate Student Supervision

Doctoral Student Supervision (Jan 2008 - Mar 2019)
Cave-to-mill : mine and mill integration for block cave mines (2019)

Population growth and economic development are expected to increase future global copper demand. The depletion of significant near-surface deposits and advances in detecting deeply buried ore has led to the mining industry progressively exploring further below the surface to discover new copper deposits. Accordingly, block and panel cave mining methods are being increasingly proposed as they allow massive, deeply situated ore-bodies to be mined economically. To improve the productivity of a mining method that will be used to excavate a growing proportion of global copper supply, an integrated mine and mill approach for planning and operating block cave mines, termed Cave-to-Mill, was developed. Key distinguishing features of cave mining, in comparison to other mining methods, are the uncertainty in the size of rock being fed to the mill and the lack of selectivity. As part of the Cave-to-Mill framework, fragmentation and sensor-based sorting studies were carried out at the New Afton block cave mine to investigate opportunities to improve overall productivity.Cave fragmentation is a key cave-to-mill parameter as it has implications on the productivity of both mining and milling processes. Fragmentation measurements of drawpoint muck, comminution tests and calibrated mill models were used to assess the impact of variations in feed size and hardness on New Afton mill performance. Analysis of historical mine and mill data showed that mill feed size and subsequently mill throughput are sensitive to the areas being mucked within the cave. A sensor-based ore sorting study, incorporating bulk and particle sorting systems, showed that rock from the New Afton copper-gold porphyry deposit is amenable to prompt gamma neutron activation analysis, and to X-Ray fluorescence sensors. A conceptual flowsheet, where both technologies are used as separate unit operations, was evaluated. It was found that the sorting concept demonstrated an improvement in the net smelter return of excavated material. Results from the study were used to develop a method to design and evaluate a block cave for the case where sensor-based sorting systems are included in the flowsheet.

View record

Piston press test procedures for predicting energy-size reduction of high pressure grinding rolls (2015)

High Pressure Grinding Rolls (HPGR) have been used for over 20 years, however the technology has not received wide industry acceptance despite reports of substantial energy advantages. One barrier is that full and fair consideration cannot be given to HPGR-based comminution circuits for early-stage mining projects, because industry standard tests require large sample sizes for evaluation of the technology. The main objective of the research was to develop methodologies, requiring small sample quantities, to predict the energy–size reduction performance of HPGRs. A key outcome is the development of three piston press testing procedures that require significantly less sample than standard HPGR evaluation methods. One method, referred to as the direct calibration methodology, involves calibrating results of piston press tests against pilot-scale HPGR tests. This methodology was developed primarily for situations where HPGR test data is only available for a composite sample and the energy requirements of individual geometallurgical units within a deposit are to be determined.To address the case where HPGR test results are not available, a second method was developed which relies only on piston press testing and empirical equations that were determined from a database of pilot-scale HPGR results. The simulation-based methodology was also developed to be able to assess the impact of changes in HPGR operation or circuit configuration on comminution performance. An existing energy–breakage model was adopted and modified for application to particle-bed comminution. The three methodologies were compared by applying them to samples from a copper-gold deposit in central British Columbia. Through utilization of these methodologies, the energy–size reduction performance of the HPGR technology can be predicted with small sample requirements which can be applied to a broad range of ore types and provide a stronger statistical basis for the process design. During development of the methodologies, significant research outcomes resulted. Controlled piston press and HPGR pilot tests on the same samples confirmed that normalized product PSDs of the respective equipment can be regarded as equivalent. Furthermore, data from particle-bed comminution tests was used to determine master curves describing breakage appearance functions for the compression mode of breakage.

View record

Improving operation and performance of Continuous Variable Discharge concentrator (2014)

Continuous discharge centrifugal concentrators have been in use for more than 20 years but their technological advantages have not yet been fully exploited due to limited fundamental understanding of the technology and lack of operating strategy to efficiently adjust the multiple interacting variables to improve performance. In addition there is no mechanism for scale up and the existing laboratory procedures have limitations for predicting metallurgical response. This thesis focuses on two main goals. Firstly to develop a gravity amenability laboratory scale test procedure and secondly to develop a procedure for tuning CVD variables to improve operational performance with the aim of increasing application.A novel optimization approach, code named NNREGA, integrating artificial neural networks, regression and a genetic algorithm, was developed and tested for tuning CVD operating variables to simultaneously maximize gold recovery and grade from a polymetallic flotation tailing. An optimum operating line was generated using a Pareto genetic algorithm. Results show that the procedure provides an efficient way of exploring the design space to learn the relationship between interacting variables and outputs and is capable of predicting an improvement in CVD performance. By generating the operating curves, the procedure provides a basis for CVD scale up. It also allows for continuous improvement and can be used as part of an operating strategy with potential to integrate into machine logic control.A Gravity Release Analysis procedure, which consists of rougher, scavenger and four incremental cleaner laboratory scale Knelson concentrator stages was developed to characterize ore amenability to CVD concentration. The procedure was used to quantify gravity recoverable gold bearing sulphides in flotation tails from a massive sulphide ore and an epithermal gold vein ore. Results show good correlation between the laboratory procedure and CVD, with the laboratory procedure results forming an upper limit for the CVD. Thus, the Gravity Release Analysis procedure can be used to predict potential CVD application and to benchmark operating machines. Based on the Gravity Release Analysis procedure, a mechanism of quantifying gravity amenability and gravity kinetics, the gravity release index, was introduced. The index can be used to quantify the relative abundance of different gravity recoverable mineral species in an ore.

View record

Quantifying, reducing and improving mine water use (2013)

Water is vital to the mining industry; mines can require substantial amounts of water and are often located in some of the driest places on earth. Reducing water withdrawals and improving mine water use are key strategic requirements for moving toward a more sustainable mining industry. Mine water requirements often have significant technical, economic, environmental and political implications. This thesis quantifies global mine water withdrawals and discusses methods of improving mine water use by reducing water withdrawals and water-related energy consumption.The thesis is composed of four main sections. First, two methods are proposed to calculate global mining water withdrawals by commodity. One method is based on the amount of water required to process a tonne of ore and the other is based on the amount of water required to produce a tonne of concentrate. A large database was created, compiling data regarding ore production, commodity production, commodity prices, and mine water withdrawals between 2006 and 2009. The study estimates that global water withdrawals range from 6 to 8 billion m3 per annum. Second, the thesis presents a case study on the challenges faced and lessons learned during the design, start-up and modification of the water systems of a large copper mine site. Third, the thesis identifies multiple mine water reduction, reuse and recycle strategies that have been implemented around the world. A model is developed and used to show the potential impact of these strategies. The results of the modelling show how a hypothetical mine could reduce water withdrawals from 0.76 m³/t to 0.20 m³/t of ore processed or lower. In particular, the combination of ore pre-concentration and filtered tailings disposal reduced water consumption by over 74% of the base case. Finally, this thesis describes and demonstrates a method of determining the lowest energy option for a mine water network. The method uses a linear programming algorithm to compare options for matching water sources with consumers at mine sites. An example illustrates the method and shows how mine water system energy requirements can be reduced by over 50%.

View record

The effect of stirred mill operation on particles breakage mechanism and their morphological features (2011)

Stirred milling is a grinding tool that is used extensively for mineral liberation, in order to achieve successful downstream processing such as flotation or leaching. The focus of this research is to understand the effect of different operating parameters on particle breakage mechanism. Operating parameters could be summarized as stress intensity on the particles which are varied by changing the mill’s agitator speed, and different ground material properties such as extreme hard/low density minerals like quartz versus soft/high density minerals like galena. Grinding performance is assessed by analysing particle size reduction and energy consumption. Breakage mechanism is evaluated using the state of the art morphological analysis and liberation. Finally, theoretical evaluation of particles flow, types of forces and energy distribution across the mill are investigated using Discrete Element Modelling (DEM). It is observed that breakage mechanisms are affected by the type of mineral and stress intensities (agitator speed) in the mill. For example, galena, the soft/high density mineral, reaches its grinding limit very fast at high agitator speed and specific energy consumption increases exponentially with the increase of the agitator speed. On the other hand, for quartz, the hard/low density mineral, the breakage rate is very slow at low agitator speed and the specific energy consumption increases linearly with the increase of the agitator speed. Fracture mechanism of the particles is also a function of the agitator speed and type of mineral. At high agitator speed, galena fractures mostly along the grain boundaries, whereas quartz breaks across the grains, which is abrasion. The morphology observation is confirmed by the DEM model, which conveyed that at higher agitator speed, the normal forces were higher than tangential forces on the galena particles compared to the ceramic grinding media particles. The core of this research is the morphology analysis, which is a novel approach to studying particle breakage mechanisms. More work is recommended in the field of morphology with other types of minerals to confirm the findings of this research. 3D liberation analysis was introduced in this research; a correlation to the conventional liberation methodology would be a major addition to the industry.

View record

Pipe flow of homogeneous slurry (2008)

The objective of this Thesis is to devise a system for the "rheology-based design" of non-settling (homogeneous) slurry pipelines that is more conducive to application by practicing engineers without impairing its accuracy or utility for research purposes. The cornerstone is the development of a new rheological model and constitutive equation for homogeneous slurry based on the aggregation/deaggregation of the suspended mineral particles. This “yield plastic” model is shown to describe a family of models that includes the Newtonian, Bingham plastic and Casson models as special cases. It also closely approximates the results of many consistency models, including power law, yield power law, Cross and Carreau-Yasuda.The yield plastic model is then used to develop design equations to determine the pressure-gradient of laminar and turbulent pipe flow. A relative energy dissipation criterion is proposed for the laminar-turbulent transition and shown to be consistent with currently used transition models for Newtonian and Bingham fluids. Finally, a new dimensionless group (the “stress number”) is proposed that is directly proportional to the pressure-gradient and independent of the velocity. When the design equations are presented graphically in terms of the stress number and the plastic Reynolds number, the resulting “design curve diagram” is shown to be a dimensionless (pressure-gradient vs. velocity) pipe flow curve. The net result is that the hydraulic design of homogeneous slurry systems only requires the use of a single constitutive equation and three engineering design equations. The results are presented in a conceptually easy form that will foster an intuitive understanding of non-Newtonian pipe flow. This will assist engineers to understand the impact of slurry rheology when designing, operating and troubleshooting slurry pipelines and, in the future, other slurry related processes.

View record

Master's Student Supervision (2010-2017)
Study of New Afton ore heterogeneity and its amenability to sensor based ore sorting (2017)

With extraction of low-grade and high throughput deposits, elimination of tonnes of uneconomic material is highly desired to reduce energy consumption and water usage in the mine/mill production cycle. Even though technologies such as sensor-based sorting has wide application for pre-concentration purposes, effectiveness of sorter systems and key parameters for sortability of a material are still in the developmental stage. Number of factors such as grade variability, mineralogical alteration and ore blending scenarios during material handling will significantly affect contents of a material resulting in unforeseen changes in downstream processes. For these reasons, the ‘ore heterogeneity’ parameter is studied to evaluate sortability of an ore material under varying mine production scenarios.Production data, drillhole data and representative drawpoint samples were provided from the New Afton copper-gold mine located near Kamloops, BC. The New Afton mine utilizes the block caving method for extraction of ore from the copper-gold alkali-porphyry deposit.The distribution heterogeneity (DH) parameter is estimated for the data sets and the quantity of potentially removable material ahead of delivery to mill is studied. The DH is defined by variation of grade of a group of samples that constitute a lot, i.e. a group being an equal tonnage of material drawn from a drawpoint and the lot being the drawpoint. With this approach, the DH is analyzed across drawpoints, vertically within a drawpoint and along drill holes with changing vertical intervals of 0.5m – 10m. The DH values are compared with copper grades and an inverse relationship is found. This finding indicated that sortability of ore material can be defined by a heterogeneity parameter, especially the information can be obtained earlier from drillcore samples. The drillcore information can indicate a measure of heterogeneity and related copper grade of an in-situ material in advance of assay samples or sensor detection where a certain degree of mixing has occurred.Overall, 27% of the sample data from the New Afton historical production record has grades less than 0.4% Cu, which is the current cut-off grade, and it correlates with relatively high heterogeneity and presents an opportunity for sorting and feed grade upgrade.

View record

The application of Laser Induced Breakdown Spectroscopy sensor system for real time ore classification (2017)

Laser Induced Breakdown Spectroscopy (LIBS) is a geoanalytical tool capable of identifying elements, and measuring element concentrations and the composition of rock samples. LIBS is a method based on a laser energy pulse that creates an ablation in the surface of a rock sample and the ionization of photons to produce a breakdown of the sample’s elemental composition. The ionization process can be captured to produce a spectrum that contains information about elemental composition. The wavelength is used to identify elements, and its intensity peaks are used to identify the concentrations of the element. The mining production cycle involves such processes as rock support, drilling, blasting, loading, hauling, dumping, reclamation and ventilation, depending on the mining method. Although pre-sorting, pre-concentration and classification techniques have been applied to aspects of mineral processing after the mining cycle, this research proposes the use of LIBS in the mining cycle, and defines the basic capabilities of a sensor with potential applications in the drilling and loading cycle, particularly with respect to shovels, drills and belt conveyors. The purpose of LIBS is not to provide an accurate measurement of the target mineral, which in this research is Copper ore, but responses from different elements that can be mineralogically and statistically related to obtain a predicted concentration of the target mineral. In this paper, the methodologies and the foundations of LIBS have been developed as a sensor and proxy to an ore sorting system for the real-time in situ classification of rock material. The research is based on samples from the Escondida Mine located in the north of Chile. The samples are divided into groups of Oxides and Sulphides. The results reveal the ability to predict Oxides, Sulphides and the discrimination of Oxide and Sulphide ores. The prediction regarding the target ores is obtained by comparing the LIBS data to Certified Analysis with ICP techniques. The results include models for the prediction of Cu content for Oxides and Sulphide ore types by LIBS analysis, as well as the discrimination of Oxide ores from Sulphide ores using this technology.

View record

Predicting HPGR performance and understanding rock particle behavior through DEM modelling (2014)

High pressure grinding rolls (HPGR) are becoming an increasingly popular energy efficient solution for comminution of hard rock ores. A significant barrier to the increased adaptation of HPGRs is the current requirement for large amounts of sample for pilot testing.The primary objective of the research was to develop a DEM based computer model for an HPGR to analyze the particle behavior in the unit and to predict its sizing information. EDEM, a DEM based software, was used to model the pilot scale HPGR unit and single particle compression test was used to evaluate the particle breakage and then used as an input parameter for the simulations. The results obtained from the simulation were then validated with the results from the pilot scale tests.Results obtained from the simulation suggested that a DEM-based model can be used to identify the pressure/force distribution profile for an HPGR roll surface that can then be used to design the appropriate piston geometry to match the HPGR pressure profile. Also, the developed HPGR model was used to estimate the critical sizing information for certain samples and machine operating conditions. The model generated similar trends as the pilot scale test with a lower magnitude of m-dot and specific energy consumption primarily due to the absence of a packed particle bed.The HPGR model, combined with powerful computers and larger sample masses for simulation, can be used as a procedure to size and select an industrial HPGR unit and to analyze the equipment behavior under various operating conditions and feed characteristics.

View record

Scale-up and operations of a vertical stirred mill (2014)

Stirred media mills are relatively new to mining industry, and several new technologies have been developed such as the VXPmill (vertical stirred mill). There is little technical understanding of optimizing and scaling-up of the VXPmill. This thesis addresses both of these issues and therefore supports commercial applications of this vertical stirred mill. Stirred media mills are influenced by a great number of operating variables. A study was conducted to understand the influence of mill speed, feed particle size and, slurry density and rheology on the VXPmill performance. For scale-up, a study was conducted to compare the batch recycle and the pendulum testing procedures. A scale-up demonstration study was also done utilizing the pilot-scale (VXP10) mill and the full-scale (VXP2500) mill to validate the procedure.The following are the main findings from this work:There is an optimum tip speed such that if too high (12 m/s) results in energy losses due to mechanical friction and heat. If too low (3 m/s) there are insufficient stresses to promote breakage. The optimum tip speed was found to be about 7 m/s.Feed particle size is an important variable when predicting the energy-size reduction relationship. A coarser feed requires more energy than a finer feed to achieve the same grind size. The batch recycle testing procedure overestimates the energy consumption as compared to the pendulum test over a broad range of grind sizes. Therefore, it should not be used for scale up applications. However, the pendulum test can be used to predict energy requirements for scale-up.By utilizing the VXP10 mill, the stress intensity of grinding beads and specific energy input control the grind size for the comminution of feldspars-quartz ore. At optimum stress intensity, the energy utilization is maximum. For the effective and accurate scaling-up of stirred media mills, it is extremely important that both the pilot-scale and the full-scale mills are operated at relatively similar operating conditions, and treating similar material of the same feed particle size. However, both mills should be operated at their optimal flow rates.

View record

Characterizing waste rock using automated quantitative electron microscopy (2013)

The leaching of metals from waste rock is directly related to the mineralogical composition of the rock. The overall study objective was to evaluate the application of automated quantitative electron microscopy to weathering waste rock. The value of mineral liberation analysis in optimizing mineral processing operations has been well documented. Application of automated mineralogical techniques, such as the Mineral Liberation Analyzer, to environmental studies is less common with no waste rock characterization studies found that specifically use the Mineral Liberation Analyzer.Mineral Liberation Analyzer methodology limitations and advantages were explored in the context of detection and quantification of primary and secondary metal-associated mineral phases. Mineral Liberation Analyzer application to waste rock weathering studies was assessed using laboratory, field cell, and experimental pile samples which were separated into particle-size fractions. Mineral Liberation Analyzer characterization included bulk modal and metal-associated mineralogy, size distribution, and mineral liberation, association, and exposure or availability (to weathering processes) and mineralogical features useful to an environmental modeller. The Mineral Liberation Analyzer consisted of a FEI Quanta 600 scanning electron microscope equipped with dual Bruker-AXS silicon drift detectors, tungsten filament and proprietary software.The Mineral Liberation Analyzer demonstrated characterization of Antamina mine waste rock which would aid the understanding of weathering processes at this and other sites, such as tailings and heap leach activity. Important mineralogical and elemental features determined were: availability / exposure, particle / grain size and shape, association (such as locking and potential mineral-mineral interactions), quantity and type (such as crystal structure reactivity), fractures and porosity. The scope of this study does not extend to linking lithology to secondary mineralogy. The Mineral Liberation Analyzer, in conjunction with geochemistry, particle surface analysis tools, chemical speciation modeling and diagnostic sequential leach can advance waste rock characterization, to improve mitigation strategies for waste rock drainage.

View record

Comparison of HPGR - ball mill and HPGR - stirred mill circuits to the existing AG/SAG mill - ball mill circuits (2013)

In the past 20 years, the energy-efficient comminution technologies, including high pressure grinding rolls (HPGR) and high speed stirred mill, have been developed and adopted in the hard-rock mining operation in order to reduce the energy consumption and improve the process performance. The combination of HPGR and stirred mill in a single flowsheet without tumbling mills has been demonstrated to be technically feasible. This research focused on the energy and cost comparisons of the existing AG/SAG ball mill circuits with two proposed comminution circuits, including an HPGR - ball mill circuit and a novel HPGR - stirred mill circuit.The main objective of this research was to advance the understanding of the potential benefits of the proposed HPGR stirred mill-based comminution circuits for low-grade, high -tonnage base metal operation. Samples and operating data were collected directly from the existing SAB/AGBC/SABC circuits to establish a base case for comparison. To support the base case, the existing circuits were fitted and simulated using a JK SimMet® model. Specific energy requirements for the proposed HPGR - ball mill circuit and HPGR - stirred mill circuit were determined from a pilot-scale HPGR and stirred mill test, in association with a JK SimMet® simulation.Results obtained from the research showed that the HPGR - ball mill circuit and HPGR - stirred mill circuit achieved a substantial reduction in energy, with considerable cost advantage over the existing SAB/AGBC/SABC circuits.

View record

Development of a laboratory scale procedure for predicting throughput of high pressure grinding rolls (2012)

The throughput capability of a high pressure grinding roll (HPGR), a critical process parameter, has been found to heavily depend on the sample type being processed. Existing HPGR test methods require the use of pilot machines and large sample quantities to assess the throughput characteristics of a certain ore type. Addressing the need for a laboratory scale HPGR test, a laboratory procedure was proposed to assess the throughput capability of mineral samples. Existing procedures were adopted from the fields of terramechanics and soil mechanics, and used as a basis for predictive HPGR throughput models. The applicability of the proposed tests was assessed through the comparison of predicted throughput with observed values from pilot HPGR testing. Results showed that outcomes of the proposed laboratory scale tests were statistically significant when used for the prediction of HPGR throughput. Primarily, the frictional properties of feed samples, as characterized by a direct shear box test, were found to be of particular significance. An approach to modelling the pressure profile which occurs on the HPGR roller surface was also proposed for potential use in a force-based model. Based on the results, an approach to HPGR testing requiring a reduced amount of sample was presented. Further work on characterizing the frictional properties of mineral samples was recommended. Analysis of HPGR outcomes indicated that strong relationships exist between power, throughput and roll gap, hence holistic approaches to HPGR modelling may be most appropriate for future predictive models.

View record

Technical amenability study of laboratory-scale sensor-based ore sorting on a Mississippi Valley type lead-zinc ore (2012)

Automatic sensor-based sorting is a clean preconcentration technique that can be used to separate valuable ore rock from waste rock based on the difference of the detected physical properties. This research evaluated the amenabilities of a Mississippi Valley type lead-zinc ore sample from Pend Oreille Mine to X-ray Fluorescence Sorting, X-ray Transmission Sorting, Optical Sorting and Microwave-Infrared Sorting using laboratory-scale bench-top sensing systems. A methodology for laboratory-scale quick evaluation of the amenability of an ore sample to automatic sensor-based sorting using bench-top sensor systems was generated as reference for future study.The preliminary testwork results showed that the two X-ray methods exhibited the best sorting results. About 37.7%~52.8% of the feed mass could be rejected as waste while above 95% of the lead and zinc was recovered in the product. The sorting feed (-37.5+26.5 mm) could be upgraded by a factor of 1.5~2. The optical sorting method seemed not as effective as the X-ray methods. Only 18.8% of the sorting test feed (-37.5+26.5 mm) was rejected to maintain above 95% metal recovery in the product. The test feed was upgraded by a factor of 1.2. Microwave-Infrared sorting results demonstrated that carbonate gangue mineral does not heat when exposed to microwave heating, while lead-zinc bearing sulfide does. Factors such as particle size, heating time and quantity of particles being heated at a time would influence microwave heating of rocks. Sorting feed of -19+13.2 mm presented the best segregation results after 10s of microwave heating. Above 95% of lead and zinc was recovered in a mass yield of 70% to the product. The test feed was upgraded by a factor of 1.4.The preconcentrate of X-ray Fluorescence sorting had a bond work index 12% smaller than that of the feed ore. The overall metal (lead and zinc) recoveries and grades in the flotation products were also improved after XRF sorting. The costs of both the grinding and the flotation reagent could also be reduced due to the reduction of the feed mass by rejecting the dolomitic gangue minerals up to 50%.

View record

A pilot-scale examination of a novel high pressure grinding roll / stirred mill comminution circuit for hard-rock mining applications (2011)

The mining industry will be faced with new challenges as the need to develop lower grade ore deposits expands to meet the rising demand for raw resources. Low-grade deposits require a substantially increased tonnage to achieve adequate metal production and have caused the consumption of energy in mining practices such as comminution to rise dramatically. If improvements could be made in the processes employed for metal extraction, the mining industry could remain sustainable for future generations. This research focused on the development of a novel comminution circuit design to addresses these issues. The circuit design incorporated two, known energy efficient technologies, the High Pressure Grinding Roll (HPGR) and the horizontal high-speed stirred mill, and examined the technical feasibility of a circuit operating without the need for a tumbling mill.The main objectives of this research were to setup pilot-scale research equipment and develop the design criteria necessary to operate an HPGR / stirred mill circuit. Testing consisted of using a copper-nickel sulphide ore from Teck Limited’s Mesaba deposit to evaluate a circuit comprised of two stages of HPGR comminution followed by stirred mill grinding. To evaluate the potential energy benefits of this novel circuit arrangement, energy consumption related to comminution was calculated for the circuit using power draw readings off the main motor and the throughput recorded during testing. To provide a basis for comparison, the energy requirements for two conventional circuits, a cone crusher / ball mill and an HPGR / ball mill, were determined through HPGR pilot-scale testing, Bond grindability testing and JK SimMet® flowsheet simulation.Results from this research showed that operating the first-stage HPGR in open circuit and the second stage in closed circuit with a 710µm screen, resulted in a circuit energy requirement of 14.85kWh/t, a reduction of 9.2 and 16.7% over the HPGR / ball mill and cone crusher / ball mill circuits, respectively. To assist in future HPGR / stirred mill studies, a refined testing procedure was developed with a reduced sample commitment and the ability to perform an energy comparison with a Semi-Autogenous Grinding (SAG) mill / ball mill circuit.

View record

Assessment of waste rock weathering characteristics at the Antamina mine based on field cells experiment (2010)

The weathering behaviour of waste rock is being evaluated using field cell experiments at the Antamina Mine. The results presented here are a component of a larger study that is being conducted in Antamina, whose objective is to understand the geochemical and hydrological behaviour exhibited by different waste rock types, and their potential operational and post-closure impacts on the environment, in order to identify and implement prevention/mitigation measures. The waste rock is currently classified into three classes based on metal (zinc, arsenic) and sulfide contents: reactive (A), slightly reactive (B), and non-reactive (C). This thesis presents the analysis only of Class B marble and hornfels material. Particle size was measured through the standard sieving method and Elutriation techniques, and surface area through geometrical estimation and the BET methods. The data gathered was correlated with chemical assay results and complemented with the mineralogical and mineral availability for leaching data obtained using a Mineral Liberation Analyzer. Minerals containing copper, lead, and zinc, and all sulfide minerals were examined. Seven field kinetic cells were installed with samples having particles of less than 10 cm in diameter. Metal leaching, elemental production rates and release rate trends from two years of data are presented. The relationship between mineral availability and field cells drainage data was investigated. A refined waste rock classification system for Class B was recommended including the incorporation of lithology, mineralogy, mineral availability for leaching, and sulfur-sulfide content.The diopside marble samples were found to be coarser than the black marble and gray hornfels samples. Large surface were reported in the black marble, this was because a relatively higher proportion of clay minerals were found in this sample.Acid-base accounting testing reported that all samples were non-acid generating. However, Cu, Pb, Zn, and Sb were reported in higher concentrations in the leachate from the field cells. Solid phase concentrations of these elements were found to increase as the size fractions decreased, but in two diopside samples, Cu, Pb and Zn minerals were available for leaching in high proportion from the coarse particles. The main sources of these elements were chalcopyrite, galena, and sphalerite.

View record

Recent Tri-Agency Grants

The following is a selection of grants for which the faculty member was principal investigator or co-investigator. Currently, the list only covers Canadian Tri-Agency grants from years 2013/14-2016/17 and excludes grants from any other agencies.

  • Advancing novel piston press testing procedures for sizing high pressure grinding rolls - Natural Sciences and Engineering Research Council of Canada (NSERC) - Engage Grants Program (2016/2017)
  • Mine-to-Mill Integration for Block Cave Mines - Natural Sciences and Engineering Research Council of Canada (NSERC) - Collaborative Research and Development Grants - Project (2016/2017)
  • Development of a laser-induced breakdown spectroscopy (LIBS) sensor system for real-time ore classification - Industrial Research and Development Internship (IRDI) Program - Networks of Centres of Excellence (NCE) - (2015/2016)
  • Pre-concentration of mount polley copper ore - Mathematics of Information Technology and Complex Systems (MITACS) - Networks of Centres of Excellence (NCE) - Internship Funds (2013/2014)
  • Selective comminution for improved liberation and reduced energy usage - Natural Sciences and Engineering Research Council of Canada (NSERC) - Discovery Grants Program - Individual (2013/2014)
 

Membership Status

Member of G+PS

Program Affiliations

 

If this is your researcher profile you can log in to the Faculty & Staff portal to update your details and provide recruitment preferences.