| 1. |
- Asbjörnsson, Gauti, 1985, et al.
(författare)
-
Comminution process modelling from a sustainability perspective
- 2018
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Ingår i: 11th International Comminution Symposium (Comminution '18). - 9781510883789
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Konferensbidrag (refereegranskat)abstract
- Mining is one of the largest industries in the world and contributes largely to the environmental emissions as well as gross domestic product growth for many countries. The demand for sustainability in the industry is continuously increasing with efforts such life cycle assessment, circular economy and even fairtrade to improve the entire supply chain from different perspectives. The process of comminution is subjected to different conditions and will influence the performance of the process and utilization of resources. In this paper the aim is to simulate comminution circuit from an operational perspective with dynamic simulations to evaluate process performance and environmental impacts and to compare it to a cradle-to-gate process. By integrating the environmental impacts into the dynamic process simulations, a higher simulation fidelity can be achieved to provide an extended operational and environmental perspective to the process assessment.
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| 2. |
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| 3. |
- Asbjörnsson, Gauti, 1985, et al.
(författare)
-
Importance of crusher control and cloud computing process monitoring of crushers
- 2019
-
Ingår i: IMCET 2019 - Proceedings of the 26th International Mining Congress and Exhibition of Turkey. ; 2019, s. 873-876
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Konferensbidrag (refereegranskat)abstract
- The main task of a crusher control system is to keep production on a desired level while simultaneously protecting the crusher from overload and fatigue failure. A stable production can be achieved through control of the crusher's closed side setting (CSS), which implies compensation of the wear of the crusher liners. A further objective is to provide with the possibility to optimize operational performance and utilization. For an efficient system the sampling rate needs to be sufficiently high and the control and optimization algorithms need to be robust. In addition, and equally important, configuration of the electrical cabinet and wiring must be able to withstand the harsh environment over time. Modelling and simulation of cone crushers have been on-going at Chalmers University of Technology during the last 25 years. With time the research has expanded to include several different aspects of cone crusher operation, design optimisation, real-time control and product yield optimization. As a consequence, a strong need for dedicated control possibilities of cone crushers have risen. The requirement for precise control led to the development of a new system for cone crusher control which was named Crusher Control Unit or CCU. The system has been further developed by Roctim to provide an independent, modular and flexible development platform for different crusher types. A unique feature is that the CCU can be retrofitted to both Hydrocone type of cone crushers as well as to Symons type independent of brand or age of the crusher. In order to remotely monitor the crusher performance and retrieve data from the CCU a cloud based solution has been developed.
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| 4. |
- Asbjörnsson, Gauti, 1985, et al.
(författare)
-
Modelling environmental impacts of aggregates with dynamic simulations
- 2017
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Ingår i: Proceedings of the 15th European Symposium on Comminution and Classification (ESCC2017).
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aggregates production is one of the largest industries in the world and contributes largely to the global environmental emissions. To estimate different product environmental footprint, the industrial standard is to use the life cycle assessment (Bart et al.) to quantify their impact on the environment. In 2011, the environmental product labels and declarations standard ISO14025 (EPD) was initiated to create transparent and comparable information for consumers. This is becoming increasingly common in Sweden for constructions and infrastructure projects, with certain limitations. The process of producing aggregates is subjected to different conditions and setup that will influence the performance of the plant as well as the utilization of energy.In this paper the aim is to simulate different processes for aggregate production from an operational perspective to evaluate process performance and environmental impact for different scenarios. The objective is to model and simulate the process with dynamic process simulations to capture the accumulated environmental footprint and its variation of the different product as they are produced. An approach for estimating the environmental footprint within established dynamic simulation platform is presented and demonstrated. The proposed modelling approach demonstrates a systematic way to evaluate the process performance and quantifying the life cycle inventory (LCI) for given conditions. The developed models can be used to optimize the different aspects of the operation depending on the defined objective function and the system boundaries. Simulating the process by manipulating configuration of the entire process has been illustrated in this paper. By integrating the environmental impacts into the dynamic process simulations, a higher simulation fidelity can be achieved to provide an extended operational perspective to the optimization and improve process analysis.
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| 5. |
- Asbjörnsson, Gauti, 1985, et al.
(författare)
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Modelling of Discrete Downtime in Continuous Crushing Operation
- 2016
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 98, s. 22-29
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Tidskriftsartikel (refereegranskat)abstract
- © 2016 Elsevier Ltd Crushing is a harsh process and production units are subjected to wear and failure over time which will reduce the overall performance of the plant. To achieve optimum process performance, both time dependant process dynamics and operating conditions should be taken into account. In this paper the aim is to simulate the process from a more operational perspective to evaluate process performance and process optimum for different operations. The objective is to model and simulate the discrete phenomena that can cause the process to alter performance and implement it with dynamic process simulations. An approach for combining discrete event simulations with time-dependent simulations for process evaluation and optimization is presented. The proposed approach demonstrates a systematic way to evaluate the process performance and locating optimum process configuration, for a given condition. The developed models can be used to optimize different aspects of the operation depending on the defined objective function and the system boundaries. Optimization of process throughput by manipulating configuration of both the grizzly and the crushers, as well as the time between calibrations has been illustrated in this paper. Adjusting the process continuously and calibrating it at the appropriate time can have major benefits when it comes to the process availability and utilization, increasing performance by 4.1–9.3% in these cases. Evaluation of process robustness and availability with regards to process specific factors and variation gave an indication of the process and unit performance under a long operating period. By combining discrete and dynamic simulation, a higher simulation fidelity can be achieved to provide a more operational perspective to the optimization and process analysis.
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| 6. |
- Asbjörnsson, Gauti, 1985, et al.
(författare)
-
Modelling of Discrete Downtime in Continuous Crushing Operation
- 2015
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Ingår i: Computational Modelling 2015, MEI conference.
-
Konferensbidrag (refereegranskat)abstract
- Crushing is a harsh process and production units are subjected to wear and failure over time which will reduce the overall performance of the plant. To achieve optimum process performance, both time dependant process dynamics and operating conditions should be taken into account.In this paper the aim is to create a framework for simulating the process from a more operational perspective to evaluate process performance and process optimum for different operational scenarios. The objective is to model and simulate the discrete phenomena that can cause the process to alter performance and implement it with dynamic process simulations. A method for combining discrete probability simulations with time-continuous simulations for process evaluation and optimization is presented. The proposed framework demonstrates a systematic approach to evaluate the process performance and locating optimum process configuration, for a given condition. The developed models can be used to optimize different aspects of the operation depending on the defined objective function and the system boundaries. Optimization of process throughput by manipulating configuration of both the grizzly and the crushers, as well as the time between calibrations has been illustrated in this paper. Adjusting the process continuously and calibrating it at the appropriate time can have major benefits when it comes to the process availability and utilization, increasing performance by 4.1-9.3 % in these cases. Evaluation of process robustness with regards to different maintenance strategies and process variation gave an indication of the process and unit performance under a long operating period. By combining discrete and dynamic simulation, a higher simulation fidelity can be achieved to provide a more operational perspective to the optimization and process analysis.
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| 7. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
ADVANCED MATERIAL MODELLING IN CRUSHING PLANTS USING REAL TIME ALGORITHMS
- 2015
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Ingår i: Computational Modelling 2015, MEI conference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In process control of crushing plants the traditional control is focused on stability control ofsingle machines and not on controlling material utilization. The reason for this is that the use ofmaterial property models is not that well known. The material models describe properties as e.g.capacity over time for a given product and this may depend on many parameters and dynamic effectsin the process. Due to this it is complicated to model and thus a methodology is needed to solve thisproblem. In this paper a novel method for modeling the current effect that the production units haveon the material presented. The paper presents a methodology how to use process data from SCADAsystem to analyze and suggest dynamic material model properties in real time.
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| 8. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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Cost And Performance Optimization Of A Tertiary Crushing Stage
- 2015
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Ingår i: ESCC 2015 Conference. - Göteborg : Chalmers University of Technology. - 9789188041012
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Konferensbidrag (refereegranskat)abstract
- There is increasing demand to optimise performance and profit of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and resent research has shown that the quality aspects of production have great influence on the optimisation results. The quality, cost, profit and capacity of a product is influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimisation software. In this paper, a novel approach use the parameters cost, profit, capacity and quality in order to perform a multi objective optimization of a crushing plant is presented. As an example a tertiary crushing stage consistent of a cone crusher and a vertical shaft impact crusher (VSI) is used as base for the designed objective function. The process has a given set of constraints that represents the conditions normal in these type of crushing applications. The first step in this paper is to identify if the range of the constraints can cause undesirable production costs when reaching for a given product property. The next step in the optimization shows how a strategy for relaxing constraint can increase overall productivity and still reach certain product properties. The conclusions made in this work are that multi objective optimization is essential when optimizing crushing plant production against multiple objectives. Relaxation of constraints can increase the overall performance of the crushing plant.
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| 9. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Framework for material modelling in a processing plant
- 2015
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Ingår i: Computational Modelling ‘15.
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Konferensbidrag (refereegranskat)abstract
- Material modelling within a crushing plant is closely dependent on both manual and automatic operations as well as a close follow up on the utilization of the plant performance from a management perspective. The desire to fully be able to utilize the crushing plant with respect e.g. to material handling is limited due to the lack of possibility to fully observe actions within the process. There are large quantities of data that can be monitored in the crushing plant SCADA system. However the data collected are governed by the quantity of actual sensors in the process. The aim with this paper is to propose a method for how-to pre-process the automatically gathered SCADA data in order to fill up dynamic models for process simulations. There is a fundamental need to increase the resolution of how the crushing plant behaves. This will be structured as a framework for analysing and suggesting model improvements that will increase the utilization and decrease both manual operations and give better performance when controlling the process.
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| 10. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Model of banana screen for robust performance
- 2016
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 91, s. 66-73
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Tidskriftsartikel (refereegranskat)abstract
- Screens are an important production unit in crushing plants. The performance of the screen is essential to the performance of the crushing plant. In this paper a mechanistic model of a banana screen is described and a novel model for screen deck configuration is presented. The developed model can be used for optimization of a screen so that it has the best possible performance with respect to different feeding conditions, in order to obtain a desired separation. The simulation results were compared to full scale test data and the conclusions from this comparison is that the screen model needs further parameters to handle the necessary screen deck configuration. An initial static model was derived to explain how the screen deck configuration will affect the screen efficiency. The modification of the screen deck parameters resulted in a better correlation both regarding size distribution and predicted capacity.
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| 11. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Size and shape simulation in a tertiary crushing stage, a multi objective perspective
- 2015
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 77, s. 72-77
-
Tidskriftsartikel (refereegranskat)abstract
- There is increasing demand to optimise yield and increase capacity of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and recent research has shown that the quality aspects of production have great influence on the optimisation results. The quality and capacity of a product is influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimisation software.In this paper, a novel approach to analyse the parameters product capacity and quality is presented. As an example a cone crusher and a vertical shaft impact crusher (VSI) is simulated in a tertiary stage. The simulation shows how capacity and product quality for a range of products will be affected when a parameter is changed. The paper also shows how wear will affect product capacity and quality.
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| 12. |
- Bengtsson, Magnus, 1973, et al.
(författare)
-
Towards dynamical profit optimization of comminution circuits
- 2017
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 103, s. 14-24
-
Tidskriftsartikel (refereegranskat)abstract
- There is an increasing demand to optimize performance and profit of comminution circuits. Research in this area has resulted in the development of numerous optimization tools, and recent research has shown that the quality aspects of the production have a great influence on the optimization results. The quality, cost, profit and capacity of a product are influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimization algorithm. In this paper, a novel approach to apply e.g. cost, revenue, capacity and quality in order to perform a multi objective optimization with the ability to handle dynamic variations of a comminution is presented. The problem with optimizations in general is that the objective function used for optimization is reduced in complexity in order to save computational time. In a comminution process performance varies with time and in order to perform a correct optimization the objective function used must be able to handle this type of dynamic behavior. The process has a given set of constraints that represents the conditions normal in these type of comminution applications. The first step in this paper is to identify if the range of the constraints can cause undesirable production costs when reaching for a given product property. In this step a dynamic response model is described that will be able to address the difficulties with optimizing dynamic systems. The next step in the optimization is the definition of the multi-objective optimization formulation including constraints for the optimization. Evaluating the result of the optimization in combination with a strategy for relaxing constraint can show how to increase overall productivity and still reach certain product properties. The conclusions made in this work are that multi objective optimization is essential when optimizing a comminution circuit against multiple objectives.
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| 13. |
- Bhadani, Kanishk, 1991, et al.
(författare)
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Application of Multi-Disciplinary Optimization Architectures in Mineral Processing Simulations
- 2018
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Ingår i: 11th International Comminution Symposium. - 9781510883789
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Konferensbidrag (refereegranskat)abstract
- Optimization is a pivotal point in distinguishing the competitiveness between industries that are developing, designing and operating products and processes. Mineral processing is an industry which operates various sub-processes and produces one or several products. The sub-processes involved are dynamic in nature and differs in discipline of operation. These dynamic sub-processes are sequentially integrated forming a mineral processing system. Currently, the developed simulations for the mineral processing systems have the potential to be used to design, operate and control mineral processing plants to an increased extent, but need broader optimization strategies to integrate multiple sub-processes involved. The scope of this research is to demonstrate application of multi-disciplinary optimization (MDO) architectures into a mineral processing simulation. A case study consisting of two sub-processes of comminution and classification circuits to produce aggregate products is used to demonstrate the application of MDO architectures. The MDO architectures are compared based on problem formulation, computational resources required and validity of the results. The optimization results using MDO architectures can be used to illustrate trade-offs between different sub-processes within the considered scope. The application of MDO architectures can facilitate the linking mathematical models of various disciplines such as comminution, and liberation in mineral processing simulation.
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| 14. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
Application of multi-disciplinary optimization architectures in mineral processing simulations
- 2018
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 128, s. 27-35
-
Tidskriftsartikel (refereegranskat)abstract
- Optimization is a pivotal point in distinguishing the competitiveness of industries that are developing, designing and operating various products and processes. Mineral processing is an industry which operates various sub-processes and produces one or several products. The sub-processes involved are dynamic in nature and differ in the discipline of operation. These dynamic sub-processes are sequentially integrated forming a mineral processing system. Currently, the developed simulations for the mineral processing systems have the potential to be used to design, operate and control mineral processing plants to an increased extent, but need broader optimization strategies to integrate multiple sub-processes involved. The scope of this research is to demonstrate application of multi-disciplinary optimization (MDO) architectures into a mineral processing simulation. A simulation study consisting of two sub-processes of comminution and classification circuits to produce aggregate products is used to demonstrate the application of MDO architectures. The MDO architectures are compared based on problem formulation, computational resources required and validity of the results. The optimization results using MDO architectures can be used to illustrate trade-offs between different sub-processes within the considered scope. The application of MDO architectures can facilitate the linking mathematical models of various disciplines such as comminution, and liberation in mineral processing simulation.
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| 15. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
CDIO Course Development for Faculty in Raw Materials Programmes
- 2017
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Ingår i: The 13th International CDIO Conference Proceedings, Calgary, Canada. - 1796-9964. - 9780889533998 ; , s. 315-326
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Konferensbidrag (refereegranskat)abstract
- In Europe, the existing MSc programmes which are linked to the thematic Raw Material content often focus mainly on technical knowledge in itself, and students graduate as professionals who know how to solve pre-defined technical problems. Students in such programmes seldom practice entrepreneurial, communication and innovation skills at a level that is needed in working life. On the other hand, the CDIO Initiative has developed a framework for modernizing engineering education by introducing such skills and thinking into the technical programmes and courses. It is widely discussed in the CDIO community that one of the constraints in implementing CDIO is faculty staff professional development. CDIO standards 9 and 10 focus on the faculty development and competencies both in terms of pedagogic as well as learning methods to deal with personal and interpersonal skills, and product, process, and system building skills. In order to bring a change and implement CDIO into the Raw Materials programmes in Europe, a modular course for training in CDIO was developed and delivered for the faculty member in the Raw Materials sector. This paper accounts for the development of the faculty training course, and provides a unique perspective on the implementation of CDIO into raw materials related programmes capturing the different models of implementation from different universities’ programmes and courses. The various universities involved provide programmes and courses across the entire value chain of raw materials from mining and minerals processing to materials design, sustainability and recycling. This paper will serve as a reference for the educators to develop and implement CDIO education methods in specific disciplines as illustrated here in the field of raw materials related programmes.
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| 16. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
Comparative Study of Optimization Schemes in Mineral Processing Simulations
- 2019
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Ingår i: IMPC 2018 - 29th International Mineral Processing Congress. ; 2019, s. 464-473
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Konferensbidrag (refereegranskat)abstract
- Modelling and simulations for mineral processing plants have been successful in replicating and predicting predefined scenarios of an operating plant. However, there is a need to explore and increase the potential of such simulations to make them attractive for users. One of the tools to increase the attractiveness of the simulations is through applying optimization schemes. Optimization schemes, applied on mineral processing simulations, can identify non-intuitive solutions for a given problem. The problem definition itself is subjective in nature and is dependent on the purpose of the operating plant. The scope of this paper is to demonstrate two optimization schemes: Multi-Objective Optimization (MOO) using a Genetic Algorithm (GA) and Multi-Disciplinary Optimization (MDO) using an Individual Discipline Feasible (IDF) approach. A two stage coarse comminution plant is used as a case plant to demonstrate the applicability of the two optimization schemes. The two schemes are compared based on the problem formulations, types of result and computation time. Results show that the two optimization schemes are suitable in generating solutions to a defined problem and both schemes can be used together to produce complementary results.
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| 17. |
- Bhadani, Kanishk, 1991, et al.
(författare)
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State of the Art in Application of Optimization Theory in Minerals Processing
- 2017
-
Ingår i: European Symposium on Comminution and Classification, Izmir, Turkey.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There has been continuous development going over the past 40 years related to the creation of models and simulation techniques to predict the behaviour of equipment and processes in minerals processing. At the same time, application of optimization theory into such modelling and simulation schemes has been applied to generate knowledge to improved performances of the equipment and processes.Different optimization techniques have been applied to design and configure different equipment and processes, yet there are no well-established formulations to reproduce the results. The research is scattered and focused on the need and application of the specific equipment or process not utilizing the optimization’s full potential.The aim of this paper is to highlight the trends in development of optimization schemes in minerals processing. By understanding the state of the art in application of optimization theory into mineral processing will further pave the possibility to develop utility in this field. The paper presents two classification schemes: State of Development Stage and State of Application Area as a basis to classify research within optimization related to mineral processing. In order to make smart and strategic decisions in minerals processing operations, it is required to further develop optimization techniques into modelling and simulation schemes to extract the relevant information. The classification schemes can be useful in defining the future focus area for research and development.
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| 18. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
Student Perspectives on Video-Based Learning in CDIO-Based Project Courses
- 2017
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Ingår i: The 13th International CDIO Conference Proceedings, Calgary, Canada. - 1796-9964. - 9780889533998 ; , s. 689-704
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Konferensbidrag (refereegranskat)abstract
- This paper aims at demonstrating the applicability of video learning in CDIO based project courses and at evaluating to what extent it benefits students. The courses are Machine Elements (PPU210), Product Planning - Needs and Opportunities (PPU085) and Engineering Design and Optimization (PPU190) in the Mechanical Engineering programme at Chalmers University of Technology. The research was carried out by first creating a set of videos for selected topics in three courses. In total, 22 videos were created including topics such as “Benchmarking”, “SWOT”, and “Prototype lab equipment instructions”. The learning outcomes of the video lectures were mapped to the CDIO syllabus. A blended learning environment was developed, i.e. the videos were utilised as additional support alongside existing learning activities. The videos were then used in the courses and the students’ feedbacks collected through a dedicated questionnaire, the regular course evaluation survey, and in student-teacher group meetings during and after the courses. The collected data was analysed to produce inferences about the applicability and utility of the video lectures. The resulting analysis shows the students’ preferences regarding the evaluated video lectures and instructions. The students find videos more appealing compared to traditional lectures. One of the main benefits highlighted is the possibility of watching the videos in parallel to the design-build-test project execution rather having the classroom lecture only. This helps in reinforcing concepts, and results in less dependency on supervisors during the project execution. Videos proved to be suitable for creating a blended learning environment and improved the perceived learning experience for the students. In order to maximize student satisfaction and interaction with the videos, the videos should be short and closely aligned to the other learning activities. The paper also suggests future improvements to be carried out for video-based learning in the courses, and proposes an easy adaptable way for teachers to develop video material.
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| 19. |
- Davoodi, Ali, 1984, et al.
(författare)
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Analysis of Screening Performance using Discrete Element Modeling
- 2017
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Ingår i: Proceedings of the Conference in Minerals Engineering. ; 2017
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Konferensbidrag (refereegranskat)abstract
- Screening is an important process in size classification of granular materials. It is a complex process due to the collision between particles and also a number of different operational parameters that effect the screening process. The aim of this paper is to evaluate screening performance in one of the LKAB crushing platforms. In this work an industrial vibration screen has been simulated by using Discrete Element Method (DEM). The simulations were validated with data from experiments and the screening performance has been analyzed by changing the parameters such as feeding rate. The result shows that DEM simulation is an effective tool for understanding the process of screening and because of the contact model between individual particles and particles and geometries the result is comparable with real process. It is shown that by increasing the feeding rate to 100 ton/h the screening efficiency can be improved by 20 percent.
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| 20. |
- Davoodi, Ali, 1984, et al.
(författare)
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Application of the Discrete Element Method to Study the Effects of Stream Characteristics on Screening Performance
- 2019
-
Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- Screening is a key operation in a crushing plant that ensures adequate product quality of aggregates in mineral processing. The screening process can be divided into the two sub-processes of stratification and passage. The stratification process is affected by the relative difference between various properties, such as particle shape, size distribution, and material density. The discrete element method (DEM) is a suitable method for analyzing the interactions between individual particles and between particles and a screen deck in a controlled environment. The main benefit of using the DEM for simulating the screening process is that this method enables the tracking of individual particles in the material flow, and all of the collisions between particles and between particles and boundaries. This paper presents how different particle densities and flowrates affect material stratification and, in turn, the screening performance. The results of this study show that higher density particles have a higher probability of passage because of their higher stratification rate, which increases the probability that a particle will contact the screen deck during the process.
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| 21. |
- Davoodi, Ali, 1984, et al.
(författare)
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DEM Modelling and Simulation of Banana Screen Classification Efficiency
- 2015
-
Ingår i: Minerals Engineering. - 0892-6875.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Banana screens are popular and frequently used in minerals processing. The screens are characterized by a high separation capacity and low maintenance need. The operation of screening usually takes place after crushing operation. The banana screens have multiple panels with variable slope which enables the feed material to flow rapidly resulting in a high screening rate. The difference between banana screens and other screens is that in banana screens the screen cut size varies with the changing slope of the decks. There are a number of factors affecting the screening operation; the deck panel slope progression, screen deck material, aperture shape, vibrational motion, open area, thickness of deck, feed rate and material properties.The aim of this paper is to simulate the screening performance by using the Discrete Element Method (DEM) and to analyse different motions that affect screening operation efficiency. Three decks with different slopes have been used and two different motions, linear and elliptical, have been evaluated at one feed rate. Figure 1 shows the overview of DEM simulation of screening process. Design of Experiment (DoE) has been used to evaluate the factors that control the value of parameters. The results show that the classification efficiency can be evaluated by conventional comparison between the feed particle size distribution and each of the product streams. The resolution of the model also enables the calculation of a critical efficiency criteria position along the screen deck. This position can be used to define a screening robustness factor. The passage probability and stratification behaviour can also be evaluated.
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| 22. |
- Davoodi, Ali, 1984, et al.
(författare)
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DEM simulation of banana screen performance
- 2015
-
Ingår i: Proceedings, ;Minerals Engineerings Conference Physical Separation 2015 June 11-12...
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Banana screening is an important size classification component. The screens are characterized by a high capacity for separation. The operation of screening usually takes place after crushing operation. The shape of the banana screens causes the feed material to flow rapidly and the result will be faster screening rate. The difference between banana screens and other screens is that in banana screens the screen cut size varies with the changing slope of the decks. There are number of factors that affect screening operation like inclination of discharge, open area, thickness of deck and feed rate.The aim of this paper is to simulate the screener deck with the help of DEM Simulation and to analyze different parameters that affect screener operation efficiency and optimizing the screener so that it has the best performance during the wear life of the screen media. The one deck banana screen are simulated, the result show when the value of deck thickness and deck slope increase the probability of particles passage through the apertures will be decrease.
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| 23. |
- Davoodi, Ali, 1984, et al.
(författare)
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Effects of screen decks' aperture shapes and materials on screening efficiency
- 2019
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 139
-
Tidskriftsartikel (refereegranskat)abstract
- Screening is a key unit operation for the large-scale separation of materials. There are certain different machine parameters and variables that affect the process of screening. The Discrete Element Method (DEM) is a suitable method to analyze parameters and variables. The main benefit of using the DEM for simulating the screening process is that, as a contact model, it provides the possibility of tracking each particle in the material flow and all collisions between particles and between particles and boundaries. There are different types of materials used for screening media, such as rubber and polyurethane, which are used in modular systems as a panel, and such as steel, which are used as a wire in the mesh. This paper presents how different materials used in screen decks affect the screening process. The materials' strength and elasticity have been examined in order to study how the aperture will change in different materials and how different shapes of the aperture and material of screening media affect the screening performance by analyzing the effect on material flow.
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| 24. |
- Davoodi, Ali, 1984, et al.
(författare)
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The effect of different aperture shape and material of screen deck on screening efficiency
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Screening is a key unit operation for the large-scale separation of materials. There are a number of different machine parameters and variables which affect the process of screening. The Discrete Element Method (DEM) is a suitable method to analyze all parameters and variables. The main benefit of using DEM for simulating the screening process is that as a particle contact model it gives the possibility to track each particle in the flow and all collisions between particles and between particles and boundaries. There are a number of different materials commonly used for screen media such as rubber and polyurethane which are used in modular systems as a panel and steel is usually used as steel wire mesh but sheet metal can also be used. This paper presents how different materials used in screen decks affect the screening process. The strength and elasticity has been examined in order to study how the aperture will change with different materials and also how different shapes of the aperture and the material of screen media affect the screening performance by analyzing different material flow.
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| 25. |
- Edelbro, Catrin, et al.
(författare)
-
European initiative on CDIO in raw material programmes
- 2017
-
Ingår i: Proceedings of the 13th International CDIO Conference in Calgary. - Calgary.
-
Konferensbidrag (refereegranskat)abstract
- One of five Knowledge and Innovation Communities (KICs), was launched in Europe in 2014and has its focus on exploration, extraction, mineral processing, metallurgy, recycling andmaterial substitution of raw materials. To reach the vision, where the European Union’sindustrial strength is based on a cost-efficient, secure, sustainable supply and use of rawmaterials, a new generation of skilled people entering industry, universities and researchneeds to be developed. Today’s technical MSc graduates in raw materials and especiallyprimary resources (i.e. exploration, extraction, mining and mineral processing and metallurgy)best suits large companies where they often act as specialists and experts. For small tomedium enterprises as well as for our future engineers other skills than technical arenecessary. As a part of the KIC Raw Materials, the education project “The implementation ofCDIO in raw material programmes” started in 2016. The project focuses, during 2016-2017,on (WP1) faculty- and (WP2) pilot case development. There are no academic institutes inEurope that have yet applied CDIO for primary resource related MSc programmes. Thispaper describes an education project within the KIC Raw material and presents key outputswith implementing CDIO in mining and metallurgy related programmes.
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| 26. |
- Evertsson, Magnus, 1967, et al.
(författare)
-
Control Systems for Improvement of Cone Crusher Production Yield and Fatigue Life
- 2015
-
Ingår i: Conference in Minerals Engineering 2015.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Control systems for cone and gyratory crushers were first introduced during the early 60ths. The common opinion is that if these systems are able to compensate for the wear of the crushing liners the production yield can be increased with 20-25%. Over the years these types of systems have been widely used but the theory behind the principles have not been thoroughly scientifically scrutinized and presented. Of special interest is the capability to protect the crushers from long term overloading commonly defined as fatigue.
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| 27. |
- Evertsson, Magnus, 1967, et al.
(författare)
-
Monitoring and validation of life time prediction of cone crusher with respect to loading and feeding conditions
- 2016
-
Ingår i: Comminution 16. - 9781510826670 ; 904 (1 Vol)
-
Konferensbidrag (refereegranskat)abstract
- The interest and need for compressive crushing in gyratory, cone and HPGR crushers are increasing since ores become more competent and more difficult to break. Compressive crushing is energy efficient as a consequence of the crushing principle and the imposed stress-state. The stress variations can be described by stress amplitudes and it is a known fact that many different materials, components and machines suffer from cyclic loading which shortens the service lifetime. This phenomena is explained by density variations of the particle beds in the equipment which in turn originates from particle segregation and feeding alignment. The phenomena is often called fatigue and the consequence is premature breakdowns and a relatively shorter lifetime than expected. In this paper, a previously developed theory for lifetime assessment of cone crushers will be used as a foundation for evaluation of full-scale operating cone crushers in minerals processing plants. Lifetime is calculated as a consequence of the load spectrum. The data shows that improper feeding conditions will substantially decrease the lifetime of the crusher equipment leading to excessive operating costs. An adequate control system should be able to recognise the hazardous lifetime decreasing overloads and to warn the operator. There are sometimes conflicting interests in the control strategies between production yield (process requirements) and crusher protection.
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| 28. |
- Evertsson, Magnus, 1967, et al.
(författare)
-
Versatile crusher control and cloud computing process monitoring
- 2019
-
Ingår i: Book of Extended Abstracts, 16th European Symposium on Comminution and Classification. ; , s. 103-104
-
Konferensbidrag (refereegranskat)abstract
- The main task of a crusher control system is to keep production on a desired level and to protect the crusher from overload and fatigue failure. A stable production can be achieved through control of the crusher’s closed side setting (CSS), which implies compensation of the wear of the crusher liners. A further objective is to provide with the possibility to optimize operational performance and utilization. For an efficient system the sampling rate needs to be sufficiently high and the control and optimization algorithms need to be robust. In addition and equally important, configuration of the electrical cabinet and wiring must be able to withstand the harsh environment. Modelling and simulation of cone crushers have been on-going at Chalmers University of Technology during the last 25 years. Over time the research has expanded to include several different aspects of cone crusher operation, design optimisation, real-time control and product yield optimization. As a consequence a strong need for dedicated control possibilities of cone crushers have risen. The requirement for precise control led to the development of a new system for crusher control which was named Crusher Control Unit or CCU. The system have been further developed by Roctim to provide an independent, modular and flexible development platform for different crusher types. A unique feature is that the CCU can be retrofitted to both Hydrocone type of cone crushers as well as to Symons type independent of brand or age of the crusher.
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| 29. |
- Grunditz, Simon, 1990, et al.
(författare)
-
Prediction of Collision Energy in the VSI Crusher
- 2015
-
Ingår i: Proceedings; European Symposium on Comminution and Classification 2015 September 7-10.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- VSI crushers are established comminution machines often used for size reduction and to improve the sphericity of rock particles. Data collection and experimental observation inside VSI crushers remains difficult, leading to lack of understanding of the full extent of the particle dynamics inside a VSI crusher. The aim of this paper is to attempt to characterize the probability of collision of particles in relation to their distance from the rotor. By comparing the number of collisions at a given location with the overall amount of collisions, the probability of a collision event related to the distance a particle has travelled from the rotor can be estimated. The result is an increased understanding of VSI crushers and the particle collision behaviour inside of a VSI crushing chamber.
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| 30. |
- Grunditz, Simon, 1990, et al.
(författare)
-
The Effect of Rotor Tip Speed of a Vertical Shaft Impactor on the Collision Energy Spectrum
- 2015
-
Ingår i: Proceedings;Minerals Engineering Conference Computational Modelling 2015 June 10-11.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The increasing restrictions on natural aggregates have led to a demand for effective production of artificial sand and gravel. VSI crushers are established comminution machines often used in order to improve the sphericity of particles. Due to the difficulty in data collection, the full extent of the particle dynamics inside a VSI crusher has remained unexplored.The aim of this paper is to use DEM simulations to model a full-scale crusher, generate a realistic material flow and make a number of crusher tests with different rotor tip speeds. Each particle’s collision energy compared to its size will provide a spectrum which can be related to the probability of breakage. This will show how increasing rotational speed affects collisions and the impact energy of particles inside the crusher. The result is an increased understanding that can allow optimization and modeling of VSI crushers with higher accuracy.
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| 31. |
- Gröndahl, Albin, 1994, et al.
(författare)
-
Diagnostics of cone crusher feed segregation using power draw measurements
- 2018
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 127, s. 15-21
-
Tidskriftsartikel (refereegranskat)abstract
- In comminution processes, the equipment normally operates at non-optimal conditions and due to poor access to crushers and deficient monitoring of them, this information is not acquired. Cone crushers have a crushing chamber that is revolved around its centre axis and crushing does not occur all at once but in a circular motion. This property gives rise to a potential non-optimal crushing in the form of power draw fluctuations due to the variance in feed across the crushing chamber with respect to e.g. mass flow, particle size distribution and other material properties. Studies have shown that a high rate of the power draw measurement provides the ability to expose a feeding miss-alignment. This paper shows how changes in the operation of the crusher, due to differences in feed material properties as a segregation, can be diagnosed and determined for future comminution process improvements.
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| 32. |
- Gröndahl, Albin, 1994, et al.
(författare)
-
Impact of Feeding Position on Power Draw and Size Reduction in a Cone Crusher
- 2017
-
Ingår i: The 15th European Symposium on Comminution and Classification.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The power draw of cone crushers, used in comminution and aggregates production, is in most cases monitored with too low sampling rate in comparison to the operating speed. This does not give adequate information on the actual operation mode and performance of the crusher during a full rotation of the eccentric motion of the mantle, leaving variance in the power draw unnoticed. This investigation has utilized a high speed measurement system for power draw on a lab scale cone crusher in order to identify an induced miss alignment in the feed, which is a common operation phenomenon, and the consequences of it. The results show that variations in the feeding alignment can be diagnosed and identified using only power draw measurements and that there are possibilities to use the approach for future control systems to improve fatigue life, operating efficiency, production yield and liberation in comminution processes.
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| 33. |
- Herbert, Juan Herrera, et al.
(författare)
-
Implementation of CDIO Initiative In New European Education Programs in Raw Materials
- 2017
-
Ingår i: EDULEARN17 Proceedings. - 2340-1117. - 9788469737774 ; , s. 6518-6526
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- EIT Raw Materials, one of the six Knowledge and Innovation Communities (KICs) initiated by the EIT (European Institute of Innovation and Technology) and funded by the European Commission, has the mission to boost competitiveness, growth and attractiveness of the European raw materials sector via radical innovation and guided entrepreneurship. It aims to significantly enhance innovation in the raw materials sector by the sharing of knowledge, information and expertise. This must generate a significant impact on European competitiveness and employment by driving and fostering innovation and empowering students, entrepreneurs and education partners driving toward the circular economy.To reach the vision, where the European Union’s industrial strength is based on a cost-efficient, secure, sustainable supply and use of raw materials, a new generation of skilled people entering industry, universities and research needs to be developed. Today’s technical MSc graduates in raw materials and especially primary resources (i.e. exploration, extraction, mining and mineral processing and metallurgy) meet the technical standards required by the raw materials industry across the full raw materials value chain and best suits large companies where they often act as specialists and experts. For small to medium enterprises as well as for our future engineers, other skills than technical are necessary.EIT Raw Materials will educate people that will have an intra- and entrepreneurial mind-set and will be able to develop their functions in new working environments, fostering the entrepreneurial and innovation skills, knowledge and attitudes needed for the entre- and intrapreneurs of tomorrowThe CDIO™ INITIATIVE is an innovative educational framework for producing the next generation of engineers. The framework provides students with an education stressing engineering fundamentals set in the context of Conceiving — Designing — Implementing — Operating (CDIO) real-world systems and products. There are no academic institutes in Europe that have yet applied CDIO for primary resource related MSc programs. Within the KIC EIT Raw Materials Academy, the overarching brand of all the KIC’s education activities are created in order to stimulate education activities and foster new ways of learning and teaching; an approved education project is focusing on the implementation of the CDIO methodology in primary resources linked programs. The project started in 2016 and focuses on faculty and pilot case development and the contributing partners are from academia, industry and research institutes. This project focuses on faculty development for an active and experimental learning by teaching the “technical” faculty through CDIO linked courses (entrepreneurship, business, etc.), communicative workshops, inspiration lectures and by involving the “business and entrepreneurial” faculty in exploration, mining, mineral processing and metallurgy related issues also through curriculum and pilot cases developed together with the industry.This paper describes how this education project is being developed within the EIT Raw Materials and will give an overview of the needed skillset of future engineers demanded in the Raw Materials primary sector. It presents key outputs about already developed and implemented activities in mining engineering and metallurgy related programs.
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| 34. |
- Hulthén, Erik, 1980, et al.
(författare)
-
Book-app as course literature in CDIO-based project courses- Students' perspectives
- 2018
-
Ingår i: Proceedings of the 14th International CDIO Conference.
-
Konferensbidrag (refereegranskat)abstract
- Course literature should aim to provide relevant information regarding the fulfillment of course objectives and be adjacent to students’ needs and preferences. The course literature in the “Integrated Design and Manufacturing” (PPU175) course at Chalmers University of Technology consisted of a printed book, which was used as a guide to projects’ implementation. However, the high price and low transferability of the book pinpointed the need of an alternative option. The solution was a book-app created by digitizing and adjusting the content of the existing book. This paper follows the development of the book-app and it examines its applicability as course literature in a CDIO-based project course considering students’ perspectives and preferences. The first version of the book-app was similar to a PDF whereas the second was enhanced with navigational features. Students’ attitudes towards the use of the book-app instead of a printed book as well as their opinions and suggestions about content formulation and app's features were collected after completion of the course through a dedicated survey and a focus group interview. The outcomes supported that although students were positively predisposed regarding the use of a book-app as course literature, they were not satisfied with the first version of the book-app due to its delayed response and low navigation capabilities. Regarding the second version, they were satisfied with its content and depth of the explanations but they encountered compatibility and navigational issues which affected their overall opinion. The paper concludes that students are ready to use a book-app as their course literature and it suggests design and content features that will enhance the usability and students' satisfaction with the book-app.
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| 35. |
- Itävuo, Pekka, et al.
(författare)
-
Feed-hopper level estimation and control in cone crushers
- 2017
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 110, s. 82-95
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes a novel feed-hopper level estimation and control scheme for addressing the known problem of unreliable and occasionally corrupted feed-hopper level measurement in a cone crusher. The approach involves estimating the feed-hopper level with an adaptive time-variant state estimator. The proposed adaptive scheme delivers asymptotically unbiased feed-hopper level estimates, despite using an inherently biased state estimator with biased measurement(s) and/or model, and therefore addresses the common pitfall of state estimators.The paper details the entire control system design procedure, from the fundamental theory, through dynamic modeling and estimator/controller tuning, to the design validation and control performance evaluation. The performance of the proposed scheme is evaluated through extensive full-scale tests in various production scenarios, including process start-up, level setpoint changes, and mass flow disturbance rejection.The full-scale tests revealed a number of benefits compared to the straightforward level control implementation. These benefits include the possibility of recovering from a temporary loss of measurement signal, smaller control effort, and increased system robustness due to an increased ability to withstand measurement errors. Therefore, the proposed scheme will enable more consistent size reduction and provide protection against performance degradation and process down-time.
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| 36. |
- Itävuo, Pekka, et al.
(författare)
-
Mass balance control of crushing circuits
- 2019
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 135, s. 37-47
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes a novel circuit-wide control scheme that addresses the challenging problem of mass balance control of crushing circuits. The control objective is to ensure 100% utilization at the circuit bottleneck and hence push the realized performance towards the theoretical maximum. The present control problem is challenging due to long transport delays, complex circuit layout, under-actuated process, several uncontrolled disturbance flows, varying number of active equipment, varying downstream demand, and changing bottleneck location. The proposed mass balance control scheme involves feeding the circuit according to actual demand and realized circuit throughput, whilst maintaining the amount of material accumulated into the circuit and ensuring the physical integrity of the circuit. Therefore, the circuit feeding is based on the realized processing capacity, rather than an individual bin level or an operator decision. To ensure the efficient use of available surge capacity, a limiting control structure is proposed to simultaneously realize the in-circuit multi-objective limit violation control and loose bin level control strategy. The proposed scheme offers a simple solution for the otherwise complex control problem, which can be easily and efficiently implemented using classic control methods. The paper details an entire design procedure, from the fundamental theory, through dynamic modeling and controller tuning, to the complete circuit control system design and implementation. The proposed scheme is evaluated under extensive full-scale and simulated experiments at various production scenarios and equipment combinations. The rigorous control experiments revealed that the proposed scheme delivered the desired behavior in every possible scenario. This enables the circuit to reach its true potential.
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| 37. |
- Johansson, Marcus, 1992, et al.
(författare)
-
A fundamental model of an industrial-scale jaw crusher
- 2017
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 105, s. 69-78
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, an analytical perspective is used to develop a fundamental model of a jaw crusher. Previously, jaw crushers were modelled in regard to certain aspects, for example, energy consumption (Legendre and Zevenhoven, 2014) or kinematics (Oduori et al., 2015). Approaches to date have been mainly property specific. In this work a physical modelling approach has been used to derive the modules, which are based on established facts of comminution machines, from the literature. A modelling methodology mainly inspired by Evertsson has been applied (Evertsson, 2000). The modules are divided into kinematics, flow, breakage, capacity, pressure and power. Each module has been derived and tested decoupled from the other modules to provide increased transparency of the module and its behaviour. The results of the modelling are presented for a baseline case of one industrial-scale jaw crusher and compared to manufacturer data. Future work will include validation and DEM simulations.
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| 38. |
- Johansson, Marcus, 1992, et al.
(författare)
-
A Novel Approach to Cone Crusher Feeding using High frequency Power Draw Measurements
- 2017
-
Ingår i: Proceedings of the 15th European Symposium on Comminution and Classification (ESCC 2017).
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The cone crusher is one of the most widely used crushing machines in comminution circuits. The performance of the machine is heavily dependent on how it is fed. The performance of cone crushers is usually quantified by the three measures; throughput, power and particle size distribution. In this research, an adjustable feeding nozzle is controlled using an adaptive algorithm to position the feeder nozzle for improved feeding conditions. By processing high-frequency power data, an estimation of the power variance can be obtained, which is in this work studied to improve the feeding conditions of the cone crusher. Step responses as well as steady state power draw is compared and used to develop a new algorithm. An adjustable nozzle have been built and evaluated in a laboratory environment. The results are also compared to using a stationary feeder. The laboratory tests show promising results for applications where trickle feeding of cone crushers is preferable.
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| 39. |
- Johansson, Marcus, 1992, et al.
(författare)
-
Cone crusher performance evaluation using DEM simulations and laboratory experiments for model validation
- 2017
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 103-104, s. 93-101
-
Tidskriftsartikel (refereegranskat)abstract
- Cone crushers are commonly used for secondary and tertiary crushing stages in the aggregate and mining industry. It has previously been demonstrated that the discrete element method (DEM) can be used to simulate rock breakage in crushers using a variety of modelling techniques. In order to provide confidence in the simulation results the DEM models need to be validated against experimental data. Such validation efforts are scarcely reported in the existing literature and there are no standardized procedures defined. In this paper a laboratory cone crusher is simulated using DEM and the results are compared with laboratory experiments. The rock material is modelled using the Bonded Particle Model approach calibrated against single particle breakage experiments. Two case simulations have been performed investigating the influence of eccentric speed. The laboratory crusher is a Morgårdshammar B90 cone crusher that has been equipped with custom machined liners, variable speed drive and a National Instruments data acquisition system. The results provide novel insight regarding the stochastic flow behaviour of particles when exited by the mantle at high frequency. The estimated product size distribution matches the experimental results relatively well when evaluating the corresponding coarse region that is feasible to calculate from the DEM product discharge data.
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| 40. |
- Johansson, Marcus, 1992, et al.
(författare)
-
Investigation of High Speed Cone Crushing Using Laboratory Scale Experiments and DEM
- 2015
-
Ingår i: Proceedings of the 14th European Symposium on Comminution and Classification (ESCC 2015). - 9789188041012 ; , s. 193-199
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cone crushers are commonly used in secondary and tertiary crushing stages in comminution circuits. A multitudeof factors and variables influence the performance in terms of throughput capacity, size reduction, power draw and wear.Crushers are normally installed and operated at a fixed eccentric speed setting. By installing variable frequency drives and realtimeoptimization algorithms Hulthén and Evertsson have shown that the eccentric speed can be used as a variable to optimizethe yield and improve the performance. However, the influence of eccentric speeds above the normal operational range hasbeen scarcely reported on in the literature.This paper aims at reporting on the result from an exploratory study where experiments and simulations have been used toevaluate cone crusher operation at high eccentric speed levels ranging from 10-40 Hz. A laboratory Morgårdshammar conecrusher has been refurbished for the purpose of the study. A preliminary set of experiments have been performed where resultsshowed that the chamber geometry has a vital importance. The same behaviour as observed in the experiments was also furtherunderstood by using DEM simulations leading to the design of a new chamber geometry.The new chamber design have been evaluated using DEM at four eccentric speeds and two different close side settings. Therock model has been calibrated by single particle breakage experiments and is based on the bonded particle model. The productparticle size distribution has been estimated by image analysis of the bonded cluster discharge. The work addresses and showsresults relevant to three areas in comminution and engineering research; Simulation driven design, DEM modelling, Conecrusher theory.
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| 41. |
- Li, Haijie, et al.
(författare)
-
Dynamic modeling and simulation of a SAG mill-pebble crusher circuit by controlling crusher operational parameters
- 2018
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 127, s. 98-104
-
Tidskriftsartikel (refereegranskat)abstract
- A semi-autogenous (SAG) or autogenous mills (AG) circuit commonly comprises a pebble (cone) crusher to deal with the critical size particles. The pebbles crusher is often oversized, and thus not fully utilized. The hypothesis put forward in this paper is that active control of the cone crusher's eccentric speed and closed side setting (CSS) can increase throughput and/or energy efficiency of the SAG circuit. To verify this hypothesis, a dynamic model of a SAG mill-pebble crusher circuit was implemented. The dynamic unit models are based on results presented by several different researchers, whose results here have been combined and implemented in Matlab/Simulink. Previous research shows that by controlling the cone crusher operational parameters, the product particle size distribution (PSD) can be altered during operation. However, few papers have been published about whether the changes of the pebbles crusher's product PSD, lead to a higher performance of the SAG circuit. This paper examines the relations between the SAG mill and the pebble crusher in closed circuit while putting emphasis on controlling the pebble crusher in order to optimize the circuit throughput.
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| 42. |
- Li, Haijie, 1990, et al.
(författare)
-
DYNAMIC MODELLING OF A SAG MILL-PEBBLE CRUSHER CIRCUIT BY DATA-DRIVEN METHODS
- 2019
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In a semi-autogenous grinding (SAG) mill and pebble crusher circuit, the behaviour of the comminution process is non-linear and time-varying due to wear and variations in the feed material. To describe such a complex system, data-driven models were introduced, along with a case study of a SAG mill circuit in Copper Mountain, British Columbia, Canada. This paper presented a mill power draw model using several regression algorithms like Artificial Neural Networks (ANN), K-Nearest Neighbours (KNN), Random Forest (RF), and Gradient Boosting method (GBM). The results were then combined by weighted mean squared errors to perform a more accurate ensemble model. The second method considered the comminution process as a time series problem, so the original dataset was re-structured, and a forecasting SAG power model was proposed by using Long Short-Term Memory algorithm (LSTM). This LSTM forecasting model applied 20 minutes of historical data to predict 2-minute SAG power draw in advance. It was shown that both the presented methods gave promising results for SAG mill power prediction.
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| 43. |
- Papadopoulou, Panagiota, 1992, et al.
(författare)
-
CDIO faculty development course – Built-in implementation
- 2019
-
Ingår i: Proceedings of the International CDIO Conference. - : Chalmers University of Technology. - 2002-1593.
-
Konferensbidrag (refereegranskat)abstract
- To successfully implement the CDIO approach in engineering programs, a holistic approach is required, connecting the philosophy of the program with teaching and learning activities in the courses. One influential component in this interaction is faculty members and their competence in providing integrated learning experiences, in using active experiential learning methods, and in assessing student learning (CDIO Standard 10). As an effort to support such faculty development, a group of universities has been conducting activities directly aiming to enable and drive CDIO implementation in the participating universities (mainly within the EIT Raw Materials programme). In this paper, we will continue reporting and critically reflecting on these CDIO-based faculty development endeavours. Initially, a faculty development course was launched in 2016 at Chalmers University of Technology and offered to participants from other universities (Bhadani et al., 2017). The paper starts by outlining the adaptation of the course into its second version, followed by investigating the experiences from the first group in 2018. The course was designed to suit both experienced and novice faculty. It offered a staged introduction to CDIO implementation alternated with sessions in which participants worked on their own course development. The rationale for this design was to increase the direct usefulness for the participants, in that they should feel engaged and involved during learning and be able to immediately apply their learning to their own course. To estimate the impact of the course on participants’ actual course design and implementation, participants’ final presentations and feedback were analysed. Interviews were also conducted to gather information about the changes made in the participants’ own teaching, as well as the perceived influence of the CDIO course on those changes. The paper could be used to support organizers of faculty development courses in other universities, by documenting a model that can be implemented as a standard faculty training course.
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| 44. |
- Papadopoulou, Panagiota, 1992, et al.
(författare)
-
Gender Differences in Student Satisfaction Surveys
- 2019
-
Ingår i: Proceedings of the International CDIO Conference. - : Aahus University Library. - 2002-1593. ; , s. 834-845
-
Konferensbidrag (refereegranskat)abstract
- Engineering programs around the world strive to increase gender balance among their students and endeavor to encourage higher female enrollment. This paper aims to investigate and understand how current engineering students perceive their courses in terms of sufficient prior knowledge and overall general impression and if there are statistically significant differences among male and female students. The discussion on possible reasons for trends in responses will assist in taking actions to accommodate both genders.The study is carried out at the Chalmers University of Technology and focuses on courses in its Mechanical, Automation, and Industrial Design Engineering programs. This study is a continuation of previous work on variations of student satisfaction between CDIO project courses and “traditional” courses (Malmqvist et al. 2018) with the addition of an analysis of gender aspects. The present study will use the same methodology, namely a mixed methods approach and investigate both closed-form questionnaire responses and free text answers in course surveys. Quantitative methods for comparing means of survey questions and qualitative analyses of free text answers for selected courses are chosen to shed light on patterns of different gender’s perceptions. Aspects of different course characteristics such as traditional, lecture-based vs. project-based and theoretical vs. applied are considered.The results demonstrate that statistically significant differences exist in how male and female students perceive some of their courses and how involved they are in answering course surveys, with this difference being more substantial at bachelor’s level than at master’s level. Possible reasons on why those differences exist and what measures, if any, should be taken to close the gap are discussed.
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| 45. |
- Papadopoulou, Panagiota, 1992, et al.
(författare)
-
Investigation of Synthetic Clay Court’s Response under Cyclic Loading
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The synthetic clay tennis court’s properties need to be examined and modified to converge towards the playing characteristics of the natural clay tennis court. The aim of this study was to investigate the responses of three distinct carpet-material combinations and evaluate how the materials’ alteration affected the results. The specimens were compressed uniaxially up to 2 kN at 400 N/s loading rate at varying number of cycles. Energy transformation, strain accumulation, step of strain accumulation and moduli of each surface combination were calculated. Results indicated that the measurements were affected by the loading history and that the carpet modification influenced mainly the energy transformation and the strain accumulation, while the material change affected additionally the moduli of the system. Conduction of the experiments enhanced understanding of the clay court’s response and could attribute to the initial modelling of the synthetic clay surface.
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| 46. |
- Papadopoulou, Panagiota, 1992, et al.
(författare)
-
Video Development Methods for CDIO-Based Project Courses
- 2018
-
Ingår i: The 14th International CDIO Conference, Kanazawa, Japan. - 1796-9964 .- 2002-1593. - 9784906122530 ; , s. 431-442
-
Konferensbidrag (refereegranskat)abstract
- Video utilization can be a powerful tool for teachers to stimulate students’ interest and support flexible and adaptive learning. Successful video-based learning implementation cannot be assured without careful consideration regarding desired quality, learning outcomes and video development methods. The investigation and sharing of experiences considering video development is indispensable and will contribute to spreading a culture of easily made, peer-reviewed videos, which will enhance teaching and learning. For CDIO-based courses, it is required that the video development methods are agile and cost-effective in production as to support continuous update of videos relevant for the course and other course activities. In this paper, we identify and describe video development methods from different CDIO-based project courses. The methods are classified based on the content type, the production style, the required resources and the video characteristics. All presented video development methods follow our general framework of video development process which has been previously published and consists of four interwoven steps - topic selection, learning objectives mapping, content generation and video recording. Based on semi-structured interviews with the course teachers, we present their experiences with those different development methods to create content specific videos pertaining to various Conceive-Design-Implement-Operate topics. As outcome, we suggest our preferable video development method depending on video content category. We conclude that the choice of video development method must consider the audience’s characteristics and needs while video content should be aligned with the course content, other learning activities and the literature. The video development methods suggested and described in this paper will assist educators to choose an appropriate video development method for their own courses and maximize the videos’ contribution to student learning.
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| 47. |
- Sörensen, Aarti, et al.
(författare)
-
Creating an international network of innovative educational labs in mining engineering
- 2019
-
Ingår i: Proceedings of the 15th International CDIO Conference.
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Konferensbidrag (refereegranskat)abstract
- This paper describes the motivation and procedure for the creation of an international network of Innovative Educational Labsin Mining Engineering. The network is primarily designed for university lecturers in mining engineering to foster a broader exchange and stimulate discussion on best practices for innovative educational lab environments. The objective is to contribute to continuous development and improvement in mining engineering education by encouraging stronger international networking, exchange, and discussion among lecturers in mining engineering education. Mining engineering, just like the mining industry,is a comparatively broad, complex and interdisciplinary as well as international field of study. In addition, mines are enormous plants which are hard to grasp and often exist out of sight of young engineers. Therefore, labs and authentic learning environments already are playing a key role in mining engineering education. In addition, due to the distinctively international nature of the mining industry, there already exists a strong network, especially among professors, in the mining engineering discipline. Both of these factors can provide valuable insights for other engineering disciplines. At the same time, the mining engineering discipline itself needs to remain contemporary and competitive, constantly developing and adapting to changing industry requirements and the international network aims to contribute to and support this continuous improvement process. The creation of this network of Innovative Educational labs in Mining Engineering is part of an ongoing project titled“CDIO II –Implementing CDIO in Raw Materials Sector”, funded by EIT Raw Materials (2018/2019). The objective of the project is to apply CDIO elements to the raw materials sector in order to drive continuous development in and contribute to a sustainable future for education in the field of Raw Materials. The vision is to create an interactive online platform to visualize this network and to make it accessible for lecturers around the world, there by contributing to stimulating a dialogue between universities about good practice in mining engineering labs
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