| 1. |
- Asnafi, Nader, 1960-, et al.
(författare)
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3D Metal Printing from an Industrial Perspective : Product Design, Production, and Business Models
- 2019
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - Vienna : Springer. - 0005-8912 .- 1613-7531. ; 164:3, s. 91-100
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Tidskriftsartikel (refereegranskat)abstract
- This paper is focused on automotive stamping tools and dies as well as the impact of 3D metal printing and metals related 3D-printing on design and production of such tools and dies. The purpose has been to find out the current industrial potential of 3D-printing as far as lead time, costs, shapes, material usage, metal piece size, surface roughness, hardness, strength, and machinability are concerned. The business transformational impact of 3D-printing is also addressed in this paper. The obtained results show that the lead time can be halved, the costs are somewhat higher, and the strength, hardness, surface roughness, and machinability of the 3D-printed metallic tools and dies are as good as those of the conventionally made. The maximum size of a metal piece that can be 3D-printed today by Powder Bed Fusion (PBF) is, in the best case, 500 mm × 500 mm × 500 mm. 3D-printing can also be used for the pattern to make the mold box in iron and steel casting. It is also possible to eliminate the casting pattern, since the mold box can be 3D-printed directly. All this has started to have a large business impact, and it is therefore of great significance to outline and execute an action plan almost immediately.
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| 2. |
- Asnafi, Nader, 1960-, et al.
(författare)
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Editorial
- 2022
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 167:9, s. 407-407
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Asnafi, Nader, 1960-, et al.
(författare)
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Production Tools Made by Additive Manufacturing Through Laser-based Powder Bed Fusion
- 2020
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 165:(3), s. 125-136
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the design and production of stamping tools and dies for sheet metal components and injection molds for plastic components. Laser-based Powder Bed Fusion (LPBF) is the additive manufacturing method used in this investigation. Solid and topology optimized stamping tools and dies 3D-printed in DIN 1.2709 (maraging steel) by LPBF are approved/certified for stamping of up to 2‑mm thick hot-dip galvanized DP600 (dual-phase steel sheet). The punch in a working station in a progressive die used for stamping of 1‑mm thick hot-dip galvanized DP600 is 3D-printed in DIN 1.2709, both with a honeycomb inner structure and after topology optimization, with successful results. 3D printing results in a significant lead time reduction and improved tool material efficiency. The cost of 3D-printed stamping tools and dies is higher than the cost of those made conventionally. The core (inserts) of an injection mold is 3D-printed in DIN 1.2709, conformal cooling optimized and 3D-printed in Uddeholm AM Corrax, and compared with the same core made conventionally. The cooling and cycle time can be improved, if the injection molding core (inserts) is optimized and 3D-printed in Uddeholm AM Corrax. This paper accounts for the results obtained in the above-mentioned investigations.
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| 4. |
- Asnafi, Nader, 1960-
(författare)
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Tool and Die Making, Surface Treatment, and Repair by Laser-based Additive Processes
- 2021
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 166:5, s. 225-236
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Tidskriftsartikel (refereegranskat)abstract
- This paper explores the possibilities to use laser-based additive processes to make, surface treat and repair/remanufacture tools, dies and molds for cold working, hot working, and injection molding. The failures encountered in these applications are described. The materials used conventionally and in the laser additive processes are accounted for. The properties of the tools, dies and molds made by Laser-based Powder Bed Fusion (L-PBF) are as good as and in some cases better than the properties of those made in wrought materials. Shorter cycle time, reduced friction, smaller abrasive wear, and longer life cycle are some of the benefits of L‑PBF and Directed Energy Deposition with powder (DED-p) (or Laser Metal Deposition with powder, LMD‑p, or Laser Cladding, LC). L‑PBF leads to higher toolmaking costs and shorter toolmaking lead time. Based on a review of conducted investigations, this paper shows that it is possible to design and make tools, dies and molds for and by L‑PBF, surface functionalize them by DED-p (LMD‑p, LC), and repair/remanufacture them by DED-p (LMD‑p, LC). With efficient operational performance as the target for the whole tool life cycle, this combination of L‑PBF and DED-p (LMD‑p, LC) has the greatest potential for hot working and injection molding tools and the smallest for cold working tools (due to the current high L‑PBF and DED-p (LMD‑p, LC) costs).
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| 5. |
- Chai, Guocai, et al.
(författare)
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Creep Behavior in A Newly Developed Heat Resistant Austenitic Stainless Steel
- 2015
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 160:9, s. 400-405
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Tidskriftsartikel (refereegranskat)abstract
- UNS S31035 austenitic stainless steel grade is a newly developed advanced heat resistant material for use in coal fired boilers at metal temperatures up to 700 °C. This new grade that has recently got two AMSE code cases shows good resistance to steam oxidation and flue gas corrosion and high creep rupture strength. This paper will mainly focus on the characterization of long term structure stability and performances such as the creep behaviors at different temperatures for up to 86,000 h at high temperatures. The creep damage mechanisms were studied using electron transmission microscopy, electron backscatter diffraction, and electron channeling contrast image analysis. The results show that the creep strength is related to the intragranular nano particles that act as obstacles for dislocation movements. Plastic deformation and transgranular fracture is the main creep fracture mechanism in the creep test samples of UNS S31035. The material has good creep ductility by formation of twins during the creep test. This material has been installed and tested in several European power plants, and has shown good performance. The material is an excellent alternative for superheaters and reheaters in future high-efficient coal fired boilers with design material temperatures up to 700 °C, instead of more costly nickel based alloy.
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| 6. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
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3D Ore Characterization as a Paradigm Shift for Process Design and Simulation in Mineral Processing
- 2021
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 166:8, s. 384-389
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Tidskriftsartikel (refereegranskat)abstract
- Current advances and developments in automated mineralogy have made it a crucial key technology in the field of process mineralogy, allowing better understanding and connection between mineralogy and the beneficiation process. The latest developments in X‑ray micro-computed tomography (µCT) have shown a great potential to let it become the next-generation automated mineralogy technique. µCT’s main benefit lies in its capability to allow 3D monitoring of the internal structure of the ore sample at resolutions down to a few hundred nanometers, thus excluding the common stereological error in conventional 2D analysis. Driven by the technological and computational progress, µCT is constantly developing as an analysis tool and successively it will become an essential technique in the field of process mineralogy. This study aims to assess the potential application of µCT systems, for 3D ore characterization through relevant case studies. The opportunities and platforms that µCT 3D ore characterization provides for process design and simulation in mineral processing are presented.
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| 7. |
- Hulme-Smith, Christopher, 1989-, et al.
(författare)
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Spreadability Testing of Powder for Additive Manufacturing
- 2020
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer Nature. - 0005-8912 .- 1613-7531. ; 166:1, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- The spreading of powders into thin layers is a critical step in powder bed additive manufacturing, but there is no accepted technique to test it. There is not even a metric that can be used to describe spreading behaviour. A robust, image-based measurement procedure has been developed and can be implemented at modest cost and with minimal training. The analysis is automated to derive quantitative information about the characteristics of the spread layer. The technique has been demonstrated for three powders to quantify their spreading behaviour as a function of layer thickness and spreading speed.
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| 8. |
- Hägg Mameng, Sukanya, et al.
(författare)
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Atmospheric Corrosion Resistance of Stainless Steel : Results of a Field Exposure Program in the Middle-East
- 2016
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 161:1, s. 33-43
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Tidskriftsartikel (refereegranskat)abstract
- Stainless steels have been widely used as architectural and construction materials because of their high degree of corrosion resistance, unique aesthetic quality, and stability in an unpolluted atmosphere. Although stainless steel is highly corrosion resistant, localized corrosion can occur in certain environments, especially in marine atmospheric conditions if the appropriate grade is not used. Exposure of stainless steel to an environment more aggressive than the limiting conditions may be harmful to its aesthetic appearance and ultimately even to its load-bearing capacity. Selecting a suitable stainless steel grade requires knowledge of the actual location of the application and the atmospheric conditions. In terms of materials selection, the austenitic stainless steel grade 316/316L has proved a very popular choice for architectural applications in many locations, but it is not always suitable at demanding sites such as marine environments in the Middle-East. In such cases the use of a higher-performance grade, often in combination with a good surface finish and established cleaning routines, is required to maintain pristine surfaces.The main objective of this paper is to present information about the atmospheric corrosion resistance of a number of stainless steels in the Middle-East at a marine site. The results obtained are analysed and discussed in terms of factors affecting atmospheric corrosion of stainless steel such as the, alloying element level, surface roughness, surface treatment, and microclimate.
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| 9. |
- Lindwall, Greta, 1981-, et al.
(författare)
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Coarsening investigations of precipitates in PM tool steel grades - an effect of nitrogen
- 2012
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer Science and Business Media LLC. - 0005-8912 .- 1613-7531. ; 157:11, s. 406-413
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental and theoretical comparisons of the coarsening rate for the MX(X=C, N or C+N) precipitate in five different tool steel grades produced by PowderMetallurgy (PM). The alloys contain different amounts of nitrogen and carbon; ranging fromhigh carbon/low nitrogen to high nitrogen/low carbon. Common for the grades is a highamount of precipitate forming alloying elements resulting in a high fraction of hard phase.Experimentally we have found out that the nitrogen rich precipitates coarsen slower, both forhigher and lower carbon content, than the carbon rich precipitates. Coarsening simulations areperformed utilizing the DICTRA software and an agreement between calculations andmeasurements can be concluded.
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| 10. |
- Lundberg, Sven-Erik, et al.
(författare)
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Ultra high speed rolling of stainless steel wire rod by means of interstand tensions
- 2005
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - 0005-8912 .- 1613-7531. ; 150:1, s. 5-11
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Tidskriftsartikel (refereegranskat)abstract
- By introduction of an interstand tension in the order of 10% of the actual yield stress of the rolled material in the intermediate stage of wire rod rolling, it is possible to increase the intermediate reductions without excessive increase of energy supply for rolling. Thus, an eight passes finishing block can be replaced by two intermediate stands and a four stand finishing block of a module type. This configuration gives two improvements on the productivity in a wire rod mill for stainless steel. First, the finish rolling speed can be increased from typically 60 m/s up to 80 m/s, meaning 33% higher rolling rate. Second, the modern twin module block system gives the possibility to introduce a single family rolling system, which gives a reduction of the downtime for roll and groove changing in the order of 20% of the production time, depending on the product mix in the mill.
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| 11. |
- Mellin, Pelle, et al.
(författare)
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Moisture in Metal Powder and Its Implication for Processability in L-PBF and Elsewhere
- 2020
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - 0005-8912 .- 1613-7531. ; 166:1, s. 33-39
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Tidskriftsartikel (refereegranskat)abstract
- The impact of moisture on flowability and spread- ability is discussed. More notably we also present research on the impact of moisture on built nickel-base material. One lot of a newly opened Hastelloy X (HX) L-PBF powder was split into two equal batches. One batch was moisturized using a programmable climate chamber, the other was un- treated. We built bars with both batches for mechanical testing, in an EOS M100, with a cold build plate. The mois- ture content of the two powder batches, before and after the build-jobs, were determined using Karl Fischer titration (KF). Regarding the periodical monitoring of moisture con- tent, it is not needed according to the findings of this paper. More moisture contributes to a slightly higher O-content in the built material, and in turn, a very slight reduction in im- pact toughness. If a newly purchased powder exhibits poor flowability or high oxygen content, the analysis using oven- desorption followed by KF is recommended. If the moisture content is high, a drying of the powder is recommended
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| 12. |
- Ouchterlony, Finn, et al.
(författare)
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Charakterisierung der Leistungsfähigkeit von ANFO- und Emulsionssprengstoffen mit Hilfe von großen Zylinderexpansionsversuchen
- 2003
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - 0005-8912 .- 1613-7531. ; 148:6, s. 231-238
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Tidskriftsartikel (refereegranskat)abstract
- Cylinder expansion tests have been made in order to measure the working capacity of commercial explosives under standardized but realistic conditions. Copper tubes, O 110/100 mm diameter, filled with ANFO or bulk emulsion explosives were detonated, the VOD and the tube wall expansion measured. From this the work capacity in terms of the Gurney energy EG, i.e. kinetic energy of tube and explosive gases, was calculated. Pure ANFO gave values of 1.6-1.9 MJ/kg, aluminised ANFO 2.5 MJ/kg and bulk emulsion 1.5-2.3 MJ/kg depending on the density. The explosive energy transfer is basically over at a volume expansion ratio of 5-10, but the aluminised ANFO keeps doing work much longer. Compared with their explosion energies however, the ANFO explosives transferred only 40-50 % of the available energy but the emulsion 60-70 % at normal densities. At densities above 1200 kg/m3, the VOD of the emulsions tends to drop off but the work capacity continues to increase. It is best described as a linearly increasing function with density. The case is finally made that the cylinder test is a better way to emulate rock-blasting conditions than the underwater test. It stops doing work at a relevant expansion ratio of the blast fumes and it has a reasonable balance between the different energies that accompany the blasting process. It can cope with charge sizes that are relevant for commercial explosives.
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| 13. |
- Ouchterlony, Finn, et al.
(författare)
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Die Swebrec-Funktion: Eine neue Korngrößenverteilungsfunktion und ihr praktischer Einsatz in der Sprengtechnik : [The swebrec function; a new fragment size distribution and its practical use for blast fragmentation]
- 2006
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - 0005-8912 .- 1613-7531. ; 151:10, s. 389-404
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents a new particle size distribution function, called the Swebrec function discovered during the work with the EU project Less Fines project. The function has just three parameters, with physical meaning, in its basic form. Yet it covers a size range of 23 orders in magnitude of fragment size and even more in an extended version. It has been tested on hundreds of sets of sieving data from different kinds of blasting and crushing of many different kinds of rock. The coefficient of determination r2 has in 95 % of the cases been better than 0.995, many times substantially better. Examples of such curve fits are given and the relation of the Swebrec function to traditional comminution concepts like the NBC concept, the t10 concept and the GGS-slope will be pointed out. Applications such as an extrapolation from the coarse range to the fines and vice versa will be shown and as will how the Swebrec function could be used to construct the fragment size distribution for muck piles from full-scale blasts, based on limited data. A final remark on how to implement the Swebrec distribution into fragmentation models will be given.
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| 14. |
- Rosenkranz, Jan, et al.
(författare)
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Untersuchung des Einflusses der Zellengeometrie auf den Flotationsprozess
- 2017
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 162:8, s. 281-288
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Tidskriftsartikel (refereegranskat)abstract
- Der Trend in der Entwicklung der Flotationstechnologie geht weiterhin in Richtung sehr großer Zellen. Ein Scale-up von Flotationszellen wird zumeist unter Beibehaltung ähnlicher geometrischer Proportionen vorgenommen, d. h. das Verhältnis von Durchmesser zu Höhe wird bei Vergrößerung des Volumens häufig konstant gehalten. Zudem werden bei dem Entwurf von Flotationsanlagen zumeist mehrere Zellen mit identischer Geometrie innerhalb einer Flotationsbank verwendet. Die Verwendung weniger Standardgrößen in einer Flotationsanlage vereinfacht einerseits Entwurf, Herstellung und Wartung der Flotationsapparate. Andererseits werden hierdurch Leistungsfähigkeit und Selektivität des Flotationsprozesses nicht notwendigerweise sichergestellt. Der Geometrieparameter, der bei gegebenem Zellenvolumen die Leistungsfähigkeit bestimmt, ist die Zellenhöhe. Sie hat Einfluss auf den hydrostatischen Druck und die Hydrodynamik der Trübe, die Wegstrecke, die Partikel-Blase-Agglomerate zurücklegen müssen, sowie die Homogenität der Durchmischung. Auch die Dicke der Schaumschicht hängt vom Durchmesser-Höhe-Verhältnis ab. Ziel der Forschungsarbeiten ist es, ein besseres Verständnis der Materialverteilung und der Suspensionseigenschaften innerhalb einer Flotationszelle zu erlangen und anhand dieser Informationen aufzuklären, wie Veränderungen der Zellengeometrie die Trennleistung beeinflussen können. Zu diesem Zweck wurden erste systematische Messungen und Analysen der räumlichen Verteilung der verschiedenen Phasen innerhalb einer 160 m3 Flotationszelle im Rahmen der industriellen Anreicherung eines armen Kupfererzes durchgeführt. Die Konzepte für die Probenahme an verschiedenen vertikalen und seitlichen Positionen der Flotationszelle werden vorgestellt. Die Ergebnisse der experimentellen Arbeiten geben einen Einblick in die räumliche Verteilung der Trübe innerhalb der Flotationszelle. Auf der Grundlage der gemessenen Phasenverteilung und Konzentrationen sowie der Partikeleigenschaften an verschiedenen Positionen innerhalb der Zelle werden Implikationen für einen optimierten Entwurf von Flotationszelle und -anlage diskutiert.
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| 15. |
- Weimer, Lucas, et al.
(författare)
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Arbeitssicherheit und Gesundheitsschutz in der Rohstoffindustrie im Kontext moderner Hochschulbildung : das SafeMine-Programm
- 2019
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 164:12, s. 505-513
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Tidskriftsartikel (refereegranskat)abstract
- Unternehmen auf der ganzen Welt stehen vor steigenden Herausforderungen bei der Rekrutierung von qualifizierten Arbeitskräften. Obwohl die verstärkten Sicherheitsbemühungen in der Rohstoffindustrie in den letzten Jahrzehnten erfolgreich waren, bleibt das Arbeitsumfeld durch seine spezifischen Anforderungen anspruchsvoll und einzigartig. Die Arbeit in der Rohstoffindustrie ist nach wie vor mit dem Vorurteil belastet, dunkel, staubig und gefährlich zu sein. Daher soll die Schaffung attraktiver und noch sichererer Arbeitsplätze dazu beitragen, die Lücken einer alternden Belegschaft zu schließen. Das vom EIT Raw Materials geförderte SafeMine-Projekt zielt darauf ab, ein ganzheitliches und belastbares Graduiertenprogramm für Arbeitssicherheit und Gesundheitsschutz in der Rohstoffindustrie zeitnah zu entwickeln. Die besonderen Ziele des SafeMine-Projekts sind die Ausbildung einer neuen Generation von qualifizierten Fachkräften und die Generierung fortschrittlicher wissenschaftlicher Erkenntnisse. Auf Grundlage einer Gap-Analyse, welche aktuelle Ausbildungsangebote zu Arbeitssicherheit und Gesundheitsschutz in der Rohstoffindustrie (MHS – Mine, Health and Safety) thematisierte, wurden die Bedürfnisse der Industrie identifiziert. Bei dieser Suche wurde kein spezifisches postgraduales Ausbildungsprogramm gefunden, welches sich umfassend und detailliert mit MHS-Themen befasst. Um die Ergebnisse zu ergänzen, wurde eine Branchenumfrage durchgeführt. Insgesamt reichten 43 Teilnehmer rund 1250 Antworten ein. Die Teilnehmenden kamen überwiegend aus Europa (76 %) mit einem beruflichen Hintergrund aus der Bergbauindustrie (47 %). Die Ergebnisse zeigen eine deutliche Lücke zwischen den aktuellen Bildungsaktivitäten im MHS-Sektor und den Erwartungen der Industrie. Auf der Grundlage der Ergebnisse wird ein angepasstes Graduiertenprogramm entwickelt. Die verbesserte Ausbildung von Führungskräften in der Rohstoffindustrie ist die Grundlage für fundierte strategische Entscheidungen in technischen und personellen Fragen und stärkt die Wettbewerbsfähigkeit der Unternehmen – so wie es auch von der Europäischen Union unterstützt und gefördert wird.
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| 16. |
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