| 1. |
- Vikström, Anna, et al.
(författare)
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Teachers´solutions : a learning study about solution chemistry in grade 8
- 2013
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Ingår i: International Journal for Lesson and Learning Studies. - : Emerald. - 2046-8253 .- 2046-8261. ; 2:1, s. 26-40
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Tidskriftsartikel (refereegranskat)abstract
- PurposeThe aim with the paper is to describe the collective exploration, process and knowledge production made in a learning study about solution chemistry Design/methodology/approachSecondary school teachers conducted a learning study with variation theory as a guiding principle, supervised by a researcher. The relationship between teaching and learning was analyzed and evaluated in a learning study cycle of three lessons.FindingsCritical aspects when teaching solution chemistry were identified, as well as enacted patterns of variation that significantly improved students´ learning. Examples of critical aspects were the particulate character of matter, especially the feature of “empty space” between particles, the connection between macroscopic phenomenon and sub-microscopic explanations and the difference between answers with everyday language and scientific language.Practical implicationsThis suggest that teachers in a learning study can produce new knowledge as well as use earlier research results when creating teaching activities that can improve their own practical work and students´ learning. Originality/valueThe study represents an example of research with the aim to improve teachers´ practice by generating knowledge in connection with teachers´ professional tasks.
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| 2. |
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| 3. |
- Gustafson, Anna, et al.
(författare)
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Draw point behavior in LKAB’s SLC mines
- 2019
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Ingår i: Rock Mechanics for Natural Resources and Infrastructure Development - Full Papers. - : Taylor & Francis. ; , s. 211-218
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Konferensbidrag (refereegranskat)abstract
- In a sublevel caving mine, the ore recovery, side rock dilution and the total ore extraction rate are determined and controlled at the draw point. The decision to stop loading at a drawpoint and continue blasting the next fan is critical. Abandonment of the draw point too early leads to ore losses and inefficient use of ore resources. On the other hand, closing a draw point too late leads to increased side rock dilution and increased production costs. The purpose of this paper is to evaluate the used technique for draw control and the potential for increasing the loading level efficiency using available data sources as well as other types of information from the Luossavaara Kiirunavaara AB (LKAB) mines.
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| 4. |
- Gustafson, Anna, et al.
(författare)
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From Face to Surface : a Fragmentation Study
- 2016
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Ingår i: Seventh International Conference & Exhibition on Mass Mining : (MassMin 2016). - Sydney : The Australian Institute of Mining and Metallurgy. - 9781925100433 ; , s. 555-562
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Konferensbidrag (refereegranskat)abstract
- The underground mining process, from in-situ characteristics of the unmined rock mass to the final mill product with fully liberated minerals, consists of a chain of unit operations. Some of them influence fragmentation while fragmentation impacts others. From a production point of view, fragmentation is a key parameter for the proper functioning of many unit operations and affects total production; it influences the ability to load, haul and crush the rock later in the process. Fragmentation varies because of rock mass strength, the presence of joints, the chosen explosive, specific charge (kg/m3) and quality of drill holes. The efficiency and result of unit operations such as drilling, blasting, loading and crushing depend on the rock properties which vary throughout a mine. Generally speaking, operations are not well adapted to the actual rock properties, leading to a non-optimised flow in production. This paper presents the initial part of a project that will build knowledge on the impact of fragmentation on each step of the production chain in an underground mine. It identifies the key parameters of fragmentation which influence the overall energy consumption and productivity in a mining operation through interviews, mine visits and a literature review. In the subsequent stages of the project, a number of field tests in the case study mine will address important segments of the production process where fragmentation is a major obstacle to improvements. Optimising the entire process, rather than isolated unit operations, will lead to increased productivity, decreased amount of interruptions and lower energy consumption.
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| 5. |
- Helldén, Gustav, et al.
(författare)
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Vägar till naturvetenskapens värld : ämneskunskap i didaktisk belysning
- 2015. - 2
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Bok (populärvet., debatt m.m.)abstract
- Vad händer när vatten fryser till is? Hur övervintrar bin? När dör en morot? Vad behövs för att ett frö ska gro? Dessa och andra till synes enkla frågor leder i boken Vägar till naturvetenskapens värld- ämneskunskap i didatisk belysning in på de stora frågorna om allt liv på vår jord, om biologisk mångfald ekologi och hållbar utveckling.Denna nya upplaga har kompletterats med två nya kapitel: ett grundläggande från fysikens område och ett om rymden.
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| 6. |
- Karlefors, Inger, et al.
(författare)
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Vägar till naturvetenskapens värld : ämneskunskap i didaktisk belysning
- 2010
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Bok (populärvet., debatt m.m.)abstract
- Vad händer när vatten fryser till is? Hur övervintrar bin? När dör en morot? Vad behövs för att ett frö ska gro? Dessa och andra till synes enkla frågor leder i boken Vägar till naturvetenskapens värld- ämneskunskap i didatisk belysning in på de stora frågorna om allt liv på vår jord, om biologisk mångfald ekologi och hållbar utveckling.
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| 7. |
- Manderstedt, Lena, 1966-, et al.
(författare)
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”… förut kunde jag inte läsa så himla bra”: ett litteraturdidaktiskt projekt med vårdnads- havare och elever i skolår F–3
- 2022
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Ingår i: Forskning om undervisning och lärande. - : Lärarstiftelsen. - 2000-9674 .- 2001-6131. ; 10:1, s. 7-30
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Tidskriftsartikel (refereegranskat)abstract
- Denna studie presenterar och analyserar ett läsprojekt i F–3-klasser vid två skolor i en mindre kommun. Litteraturläsning i skolan kombinerades med lässtrategiundervisning och boksamtal som övades i hemmen. Bokurvalet omfattade en bilderboksserie i pixiboksformat för förskoleklassens elever och mer omfattande böcker i skolår 1–3. Eleverna förväntades läsa med eller för vårdnadshavare eller annan närstående, samtala om det lästa och träna de båda läsförståelsestrategierna förutspå respektive sammanfatta. Läsprojektet pågick under sex veckor, och data samlades in genom veckovisa enkäter till vårdnadshavare och, efter avslutat projekt, fokusgruppsintervjuer med elever. Såväl elever som vårdnadshavare upplevde att mängden av textläsning bidrog till att utveckla elevernas läsfärdighet, och bokurvalets och boksamtalets betydelse kommenterades överlag positivt av deltagarna. Läsprojektet belyste och problematiserade skolans kompensatoriska uppdrag för elever som inte har ett väl utvecklat lässtöd hemifrån.
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| 8. |
- Shekhar, Gurmeet, et al.
(författare)
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Development of a model for economic control of loading in sublevel caving mines
- 2019
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Ingår i: Mining Technology:Transactions of the Institutions of Mining and Metallurgy. - : Taylor & Francis. - 2572-6668 .- 2572-6676. ; 128:2, s. 118-128
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an economic model for optimizing loading at the draw point in sublevel caving (SLC) operations. The input data consist of estimated bucket grades based on bucket weights from Load Haul Dump machines. This information, together with average operational mining costs, was used to create an economic model providing a real-time economic assessment of the draw point performance for SLC rings. The results demonstrate the importance of continuous draw point monitoring to optimize SLC operations. The proposed model provides an economic assessment of operating draw points and will help mine personnel to decide when to stop loading from a blasted ring. It can also help mine management understand the complexity of material flow in SLC operations. Finally, it provides operational flexibility for the mine to optimize loading at the draw point by increasing ore recovery while maintaining operational control of draw point performance.
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| 9. |
- Shekhar, Gurmeet, et al.
(författare)
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Development of an optimal draw control strategy for a sublevel caving operation at Malmberget mine
- 2020
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Ingår i: Mining Technology. - : Taylor & Francis. - 2572-6668 .- 2572-6676. ; 129:2, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- This paper addresses the identification of the optimal draw control strategy for a sublevel caving (SLC) operation at Malmberget mine in Sweden. Two mathematical models, a probability model and an economic model, were created using five datasets: bucket weights, bucket grades, extraction ratio, mine economics parameters and production constraints. The probability model was used to generate a set of simulated bucket weights and corresponding bucket grades which acts as a ‘virtual mine’ environment. The economic model assesses the economic impact of loading at the draw point. Two approaches to draw control were tested using the ‘virtual mine’ created by the probability model. Based on the results of the simulation tests, an optimal draw control strategy is suggested for a field test at the mine. The new draw control strategy optimises further the loading operation at Malmberget mine. The paper shows a roadmap for optimising draw control strategy for SLC operations.
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