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  • 1.
    Beyglou, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    On the Operational Efficiency in Open Pit Mines2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Open pit mines constitute more than half of global minerals production. Yet most of the large, high-grade, and close to the surface deposits have been depleted or are currently in production. Besides, volatility in commodity prices and stringent environmental regulations limit the up-scaling expansions in large open pits. Consequently, the mines are determined to increase their operational efficiency in order to thrive. This has recently led to major metallurgical improvements in the processing of ores; whereas the improvements in mining of the said ores are relatively overdue in terms of efficiency and technological advancement. This thesis concentrates on the mining activities and their efficiency in open pits with a focus on drilling, blasting, loading, and crushing. As all of these tasks revolve around the fragmentation of run-of-mine ore, their relationships and efficiencies are explored within the context of fragmentation.

    Fragmentation is a result of complex interactions between rockmass, blasting geometry, explosive, and timing sequence of blast holes. The influence of rockmass and timing sequence on fragmentation and efficiency are explored, as well as the target fragmentation for efficient loading and crushing. Moreover, the techniques for measuring fragmentation are evaluated as to whether they can benefit mines in terms of efficiency. As the circumstances in open pits are essentially site-specific, these issues are addressed as a case study of the Aitik mine in Sweden.

    The research comprised four elements. First, the influence of rockmass fractures on blast results and downstream efficiency was evaluated via full-scale field trials. The fractures in and around the case study mine were mapped using a photogrammetric technique and six production blasts were adapted to the major fracture sets to evaluate the effect of initiation direction on downstream efficiency. Second, the influence of the timing sequence of blast holes was explored within the theories of stress waves interaction and their consequent effect on fragmentation. Theoretical and numerical solutions were accompanied by six field trials in full-scale to evaluate the influence of short delay times on fragmentation and efficiency. Third, an empirical study was conducted to correlate fragmentation to the efficiency of loading and crushing; this was done to define a target fragmentation for the studied case. Finally, the techniques to assess fragmentation were discussed both quantitatively and qualitatively.

    The findings indicated that rockmass fractures have a significant influence on the quality of blasts and efficiency of downstream tasks. In the case study mine, adjustments to orientation of drill pattern and initiation direction of blasts suggested that careful experimentation in this regard can yield a favourable initiation direction with respect to existing discontinuities. Finer fragmentation and higher loading efficiencies can be achieved by adapting the blast designs to the existing fractures, which can lead to significant savings in the long run. On the contrary, the influence of stress waves interaction on blast results turned out to be marginal. Neither the theoretical and numerical solutions nor the field trials showed any significant improvements in blast results from short delays. In fact, it was found rather implausible to expect any noticeable improvements by using short delays.

    The empirical method to evaluate target fragmentation proved useful as well. It was shown that by incorporating different data from various sources in a mine, one can follow the ore from muckpile to loaders and then to crushers. Having a qualitative understanding of the fragmentation, and by developing tools to measure efficiency, one can estimate what fragmentation is most favourable for an efficient operation. Finally, two image-based methods to assess fragmentation were discussed in terms of repeatability and statistical significance. It was found that the scatter in both methods is rather large, introducing a certain ambiguity in representativeness of their results. Admittedly, it was found that in matters of long-term efficiency, the number, size and representativeness of assessed samples are of more importance compared to the accuracy of individual measurements.

  • 2.
    Beyglou, Ali
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Schunnesson, Håkan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Target fragmentation for efficient loading and crushing: The Aitik case2017In: The Southern African Journal of Mining and Metallurgy, ISSN 2225-6253, E-ISSN 1543-9518, Vol. 117, no 11, p. 1053-1062Article in journal (Refereed)
    Abstract [en]

    Blast-induced fragmentation has a significant influence on the operational efficiency of open pit mines, especially on loading and crushing, the two immediate tasks after blasting. This study presents an empirical method to determine the target fragmentation for efficient loading and crushing at the Aitik mine in Sweden. In the study, the loading efficiency of rope shovels was correlated to the energy consumption and throughput of a gyratory crusher. Two photographic techniques were utilized to assess the feed fragmentation, considering the lithological origin of the ore as an indicator of hardness. The results indicate ore hardness is most influential in mid-range fragmentation, with a marginal effect in coarser fragmentations. The influence of fragmentation is more pronounced in the coarse region, with a sudden reduction in efficiency for P80 values coarser than 800 mm. The results suggest tailoring the fragmentation to a P80 of 600-800 mm could lead to higher operational efficiency at Aitik. 

  • 3.
    Beyglou, Ali
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Schunnesson, Håkan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Face to Surface –Task 1: Baseline Mapping of the Mining Operation in Aitik2015Report (Other academic)
    Abstract [en]

    “Face to Surface” is a project within the strategic innovation program “Mining and Metals”, which is a collaboration between Vinnova, Formas and Energy Agency of Sweden with additional funding from Boliden Mineral AB and LKAB. The project is aimed to improve productivity and efficiency of mining activities through optimization of the overall production chain. The current status report corresponds to the first task of the project–Baseline Mapping.The report presents the overall process chain of mining operation in Boliden Aitik copper mine, Sweden. The production chain is initially described as a system of singular processes. Each process is then described in more details, including inter-relations and downstream effects of each process within the operation. The report provides a basis for identification of potential fields of improvement in the process. The subsequent tasks of the project will be conducted upon internal discussions based on the findings of this report.

  • 4.
    Beyglou, Ali
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Schunnesson, Håkan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Nils
    Boliden Mineral AB.
    Adjusting Initiation Direction to Domains of Rock Mass Discontinuities in Aitik Open Pit Mine2015In: 11th International Symposium on Rock Fragmentation by Blasting: Fragblast11, Carlton, Vic: The Australasian Institute of Mining and Metallurgy, 2015, p. 385-391Conference paper (Refereed)
    Abstract [en]

    As demand for optimisation of mining processes increases, more attention is drawn to blast performance and fragmentation improvement. Fractures and discontinuities are among the most influential factors in blast results, therefore one of the initial steps towards blast optimisation is to gather information about the rock mass and integrate it in blast design. This paper presents a method for assessment of rock mass discontinuities and integrating it in production blasts in the Aitik open pit copper mine in Sweden. 3D photogrammetric techniques were utilised to map discontinuities and distinguish domains of similar geologic structures in the pit. As a pilot study for a future campaign, four different initiation directions were tested through six pilot blasts in one of the domains. The results were compared in terms of swell and loading efficiency of rope shovels to identify the correlation between blast performance and initiation direction compared to major discontinuity families. It was established that in the trial domain, blasts initiated towards north or north-west yielded larger swell and better performance of loading. Comparing these blasts with discontinuity families show that there is a correlation between blast performance and initiation direction according to the dip and strike of these discontinuities. Such knowledge can be used for future blasts in the same domain to increase long-term operational efficiency through slight modifications in drill pattern and initiation design.

  • 5.
    Niklasson, Bengt
    et al.
    Geosigma.
    Olsson, Mats
    EDZ Consulting AB.
    Beyglou, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Does Charge Confinement Affect the Vibration Level in Blasting?: Phase I-Feasibility Study2014Report (Other academic)
  • 6.
    Niklasson, Bengt
    et al.
    Geosigma.
    Olsson, Mats
    EDZ Consulting AB.
    Beyglou, Ali
    Swebrec.
    Petropoulos, Nikolaos
    Swebrec .
    Inspänningens Betydelse för Vibrationsnivån: Etapp 2 Fältförsök2016Report (Other academic)
    Abstract [en]

    Blasting in urban areas must involve techniques to control the vibration level. Charge confinement is one of the parameters that are believed to influence the vibration level. A charge could be too confined due to:- Incorrect charge calculation (charge weight is too small for the drilled burden)- Incorrect interval-time (holes behind are initiated before holes ahead)- Incorrect selection of explosive for the burden or an influence of dead pressing- Unfavourable selection of geometry- Drill hole deviationA common opinion among blasters is that an increased confinement results in a higher vibration level. Is there a physical explanation for this or is it just a common misunderstanding established a long time ago? A feasibility study was previously conducted and reported in BeFo Report 132, (Niklasson et.al, 2014). The report comprised a literature study and an assessment of a number of observed misfires in tunnels, still with correctly detonating charges but with a reduction of more than 50 % in pull or rock breakage. It also comprised a statistical analysis of some of the rounds. The result of the study found no evidence for a relationship between degree of charge confinement and vibration level.As a result of the feasibility study a field study was proposed. This study was performed in a quarry, some 40 km north of Stockholm, close to Arlanda airport. A number of single holes were blasted; both holes with full breakage and confined holes and the vibration levels were measured.13 single holes with full breakage and 10 totally confined single holes were blasted. The burden was 1.5 m for the holes with breakage and the confined holes had a distance to the free surface of some 15 m. The hole diameter was 45 mm and hole depth 3 m. The holes were charged with a dynamite explosive, Minex Eco, and the charge weight was 1 kg/hole. The charges were initiated with electric detonators. All holes were stemmed.The vibration levels were measured in three holes with a depth of 3 m. In the bottom of the holes thee-axial geophones were grouted. A forth geophone was placed on the surface.Single hole blasting were performed with very good result. The holes close to the surface gave full breakage while the confined holes showed no breakage.The vibration signals were vector summarised and analysed. The distances from each hole to each geophone was determined. The vibration PPV-values were plotted as a function of the distances.The final result showed that there were no significant differences in vibration levels between confined holes and holes with full breakage.Key words: Vibrations, confined holes, blasting, geophones, grouting, quarry

  • 7.
    Nyberg, Ulf
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Klippmark, Victoria
    LKAB.
    Karlström, Hans
    LKAB.
    Beyglou, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Petropoulos, Nikolaos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Short time measurements of toxic fumes from detonation of emulsion explosive: Initial tests in blast chamber2015Report (Other academic)
    Abstract [sv]

    Spränggaser uppmätta med hjälp av en rökgasanalysator och detonationshastigheten VoD rapporteras för 18 tester utförda i en 35 m3 sprängkammare under en vecka juni 2014. Testerna för Swebrec:s syrebalanserade rena E682 och E682 med inblandning av Al eller torra ANprills i glasrör visar att toxiska gaser (CO och NOx) generellt ökar för det rena emulsionssprängämnet med tillsatser av 5 % Al respektive 30 % torra ANprills. Vid jämförelse av blandningsemulsion med ren emulsion är CO en faktor 1,6–1,9 högre för tillsatser av 30 % torra ANprills. För NO varierar skillnaderna i ppm-värdena för både 5 % Al och torra 30 % ANprills med laddningsdiameter; förhållandet varierar från ca 1,3 för Ø65,6 mm laddningar till ca 2,8 för Ø27,0 mm laddningar vilket tyder på en snabbare och effektivare förbränning för de större laddningsdiametrarna. VOD mätningarna visar för E682 ökande värden med laddningsdiametern. Den producerade volymen CO och NO per kg sprängämne ökar med minskande laddningsvikt (diameter) vilket kan tolkas som att förbränningen är effektivare med ökande diameter.Det finns också en avtagande trend för NOx-värden över tiden som sannolikt kan förklaras som ett resultat av sekundär oxidation av NO till NO2 (2NO + O2 → 2NO2) när spränggaserna blandas med sprängkammarens atmosfär. De uppmätta O2 värden är ofta strax under 21 % efter sprängning men ytterligare något lägre för de större laddningarna.

  • 8.
    Petropoulos, Nikolaos
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Beyglou, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Novikov, Evgeny
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Improved blasting performance through precise initiation2013In: EFEE-7th World Conference on Explosives & Blasting, Moscow: European Federation of Explosives Engineers , 2013, Vol. 1, p. 20-26Conference paper (Refereed)
    Abstract [en]

    Blast-induced fragmentation is an important factor in optimization of downstream processes in a mine. Several researchers believe that the fragmentation can be improved by means of precise short inter-hole delay times. Six full-scale trials with different inter-hole delay times of 1, 3, 6 and 42 ms (0.14, 0.42, 0.84 and 6 ms/m of burden, respectively) were conducted in Boliden Aitik open pit copper mine in Sweden. Electronic detonators were used for short inter-hole delay times, which correspond to different wave interactions between the neighboring blast holes. All the trials were carried out in more or less similar geological conditions. MWD data, swelling, fragmentation and crusher efficiency have been evaluated in the trials. Based on these trials, the short inter-hole delay times did not have a significant effect on fragmentation, swelling and crushability. However, a reduced number of boulders was observed for short delays, suggesting that the coarse region of the distribution curve was influenced rather than the fine part of it.

  • 9.
    Petropoulos, Nikolaos
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Beyglou, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Novikov, Evgeny
    Boliden Mineral AB.
    Fragmentation by blasting through precise initiation: Full scale trials at the Aitik Copper mine2014In: Blasting and Fragmentation, ISSN 1937-6359, Vol. 8, no 2, p. 87-100Article in journal (Refereed)
    Abstract [en]

    Fragmentation is an important factor for improving downstream processes in mine operations. Six trials have been conducted at the Aitik copper mine to investigate the effect of ultra-short inter-hole delay times, i.e. smaller than 1 ms/m of burden, on fragmentation. Swelling, MWD data and crusher efficiency were also evaluated for trials. According to the results, the effect of examined short inter-hole delay times, i.e. 0.14 to 0.86 ms/m of burden, on fragmentation was found to be marginal. Delay time of 0.43 ms/m of burden resulted in slightly finer fragmentation and larger swell; however, the effect of short delays was overshadowed by the effect of small variations in specific charge.

  • 10.
    Petropoulos, Nikolaos
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Novikov, Evgeny
    Beyglou, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Improved blasting results through precise initiation: results from field trials at the Aitik open pit mine2013Report (Refereed)
    Abstract [en]

    Blast-induced fragmentation plays a leading role on mining efficiency, hence many studies have been conducted in order to understand the mechanisms behind rock breakage and to improve the fragmentation. This report presents the results from field tests conducted at the Aitik mine belonging to Boliden Mineral AB in Sweden, which is part of a project called Vinnova. The project aims to evaluate the effects of short delay time blasting on fragmentation and other post-blast parameters which influence the comminution process, e.g. swelling and crushing.A total number of 6 benches were assigned for trials with different inter-hole delay times. Two of the benches were blasted with pyrotechnic Nonel caps and were used as references for further comparisons. Two benches were blasted with 1 ms of inter-hole delay time by use of electronic detonators. Two other benches were also blasted by electronic detonators, but with 3 ms and 6 ms of inter-hole delay time respectively. MWD (Measure While Drilling) system was used to log and analyze the drilling process in order to investigate the penetration rate and specific energy of drilling, which represent the hardness of the rock. GPS (Global Positioning System) and RTK (Real time Kinematic System) were used for measurements of benches’ swelling. The blasts were also filmed using a high-speed camera. Image analysis with Split-Desktop software was used to analyze the fragmentation of the rock after blasts. A series of images was shot from trucks carrying the ore and was later analyzed to obtain the fragmentation for each bench. Minestar integrated operation and mobile equipment management system was used to log the data from the fleet in the mine. The data were later used together with the crusher energy consumption logs to evaluate the energy efficiency of the crushing process for the ore from each bench.The tests showed that the inter-hole delay time of 3 ms resulted in the finest fragmentation among all benches; all examined values i.e. x50, x80 and xmax showed improvements upon other benches. However, the crushing energy of the ore from this trial was the highest among all. Two trials with 1 ms inter-hole delay time did not result in any significant variation compared to reference benches. The difference in x50 values were ignorable, the same is true for crushing energy of the mentioned trials. The bench with inter-hole delay time of 6 ms resulted in the lowest crushing energy among other trials. However, the bench gave more boulders and coarser fragmentation compared to reference benches.Altogether, the results did not lead to any solid conclusion regarding the effect of the short delay times on fragmentation. Such ambiguity might be resulted by various sources of errors in data acquisition and analysis, as well as uncertainties regarding geology of the test area. In order to investigate the effect of delay times on blast results, more trials with more detailed data acquisition method is necessary.

  • 11.
    Yi, Changping
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Beyglou, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Stress wave interaction between two adjacent blast holes2016In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 49, no 5, p. 1803-1812Article in journal (Refereed)
    Abstract [en]

    Rock fragmentation by blasting is determined by the level and state of stress in the rock mass subjected to blasting. With the application of electronic detonators, some researchers stated that it is possible to achieve improved fragmentation through stress wave superposition with very short delay times. This hypothesis was studied through theoretical analysis in the paper. First, the stress in rock mass induced by a single-hole shot was analyzed with the assumptions of infinite velocity of detonation and infinite charge length. Based on the stress analysis of a single-hole shot, the stress history and tensile stress distribution between two adjacent holes were presented for cases of simultaneous initiation and 1 ms delayed initiation via stress superposition. The results indicated that the stress wave interaction is local around the collision point. Then, the tensile stress distribution at the extended line of two adjacent blast holes was analyzed for a case of 2 ms delay. The analytical results showed that the tensile stress on the extended line increases due to the stress wave superposition under the assumption that the influence of neighboring blast hole on the stress wave propagation can be neglected. However, the numerical results indicated that this assumption is unreasonable and yields contrary results. The feasibility of improving fragmentation via stress wave interaction with precise initiation was also discussed. The analysis in this paper does not support that the interaction of stress waves improves the fragmentation.

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