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  • 1. Arvanitidis, Ioannis
    et al.
    Nyberg, Ulf
    Ouchterlony, Finn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Diameterns inverkan på detonationsegenskaperna hos emulsionssprängämne E682 i cylinderprovet2004Report (Other academic)
    Abstract [en]

    Cylinder expansions tests with 4 different diameters ranging from 40 to 100 mm have been conducted on the generic emulsion explosive E682, both pure and with 20 % ANFO content. The work capacity is expressed in terms of the Gurney energy EG, which equals the sum of the kinetic energy of the copper tube and the radial kinetic energy of the gases. The purpose was to study the effect of charge diameter on the explosive's work capacity expressed as the Gurney energy and to supplement earlier work done by Nie (2001). The radial expansion has been measured as well as the velocity of detonation in 11 copper tubes. The effect of ANFO granules were tested by making a mixture of E682 with 20% ANFO. The ANFO used in the present study is Anolit from Dyno Nobel, which basically is the same product as the Prillit A used by Nie. The average density of pure E682 was 1130 kg/m3 and that of E682 with 20% ANFO 1200 kg/m3. The results from the new batch of E682 show similarities with the old batch regarding VOD as function of inverse charge diameter but the trend of the Gurney energy is different from the first experiments carried out by Nie. This could be due to previous tolerance variations in the tube dimensions. The Gurney energy seems to be independent of the charge diameter between 40-100 mm in the new experiments. The measured Gurney energy for pure E682 was 1.77 ± 0.06 MJ/kg and that of E682 with 20% ANFO 1.71 ± 0.07 MJ/kg which is somewhat lower. The use of 20% ANFO in E682 results in the same volume based Gurney energy as for pure E682 however. The overall average is 2.02 ± 0.02 MJ/dm3. The energy utilisation ratio is 0.58 ± 0.03 for pure E682 and 0.53 ± 0.03 for E682 with 20% ANFO. This is slightly lower than for the Titan 6000 series gassed bulk emulsion but higher than for pure ANFO. The detonation pressure decreases with the charge diameter however and this indicates that a smaller hole diameter in rock blasting leads to a lower detonation pressure without loosing work energy when keeping the powder factor constant.

  • 2.
    Christiansson, Rolf
    et al.
    SKB.
    Olsson, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Niklasson, Bengt
    Skanska Teknik, Göteborg.
    Studier av sprängskador i Äspö-laboratoriet2005In: Bergsprängningskommittén Diskussionsmöte BK 2005, Bergsprängningskommittén , 2005, p. 139-152Conference paper (Other academic)
    Abstract [sv]

    En ny tunnel med 70 m längd byggdes på 450 m djup i Äspölaboratoriet 2003. Det ställdes speciella krav på begränsning av sprängskadezonens djup med hänsyn till planerade experiment.Tunneln drevs med galleri och bågformad låg pall för att minimera sprängskador i sulan. I huvuddelen av tunneln användes initieringsystemet Nonel MS och LP. I de tre sista salvorna av galleriet testades elektroniksprängkapslar. Skonsamhetsgraden för vägg och tak var normal med en tillåten skadezon på 0,3 m. Däremot tillämpades samma skonsamhetsgrad även för botten. I övrigt användes normal sprängteknik och normala sprängämnen som Dynotex 17 och Dynorex.Arbetet följdes noggrant genom dokumentation av utfört arbete. Vibrationsmätningar utfördes på nära håll samt på stort avstånd, 1,5 km från arbetsplatsen. Språng¬skador har undersökts genom sågning och sprickkartering.Föredraget kommer att presentera projektet, framförallt (1) erfarenheter från vibra¬tionsmätningar av samtliga sprängsalvor (noggrannheten i geofonmätningarna; totala antalet spränghål i salvorna; bomsalvor; avståndet från salvorna och geo¬logiska strukturer), (2) P-vågshastigheten i tunnelns närområde, (3) faktorer som påverkar utvecklingen av sprängskador, och (4) förslag på kontrollåtgärder som kan leda till att begränsa skadezonen i praktiskt tunnelarbete.

  • 3. Christiansson, Rolf
    et al.
    Olsson, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Niklasson, Bengt
    Studies of blast damage at the Äspö Hard Rock Laboratory2005In: 3rd European Federation of Explosives Engineers (EFEE) World Conference on Explosives and Blasting, 2005, p. 425-434Conference paper (Refereed)
  • 4.
    Esen, Sedat
    et al.
    Luleå tekniska universitet.
    Nyberg, Ulf
    Arai, Hiroyuki
    Ouchterlony, Finn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Determination of the energetic characteristics of commercial explosives using the cylinder expansion test technique2005Report (Other academic)
  • 5.
    Ghosh, Rajib
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Zhang, Zongxian
    LKAB, Research & Development, 983 81 Malmberget.
    An investigation of borehole stability in LKAB Malmberget underground mine, Sweden2013In: Rock Characterisation, Modelling and Engineering Design Methods -: Proceedings of the 3rd ISRM SINOROCK 2013 Symposium / [ed] Xia-Ting Feng; John A. Hudson; Fei Tan, Leiden: CRC Press/Balkema , 2013, p. 747-752Conference paper (Refereed)
    Abstract [en]

    Instability in production blast holes causes poor fragmentation, lower ore recovery, delay in production and higher costs in crushing and grinding. In this investigation, three large ore bodies named Alliansen, Fabian and Vi-Ri were selected. A video camera was used for mapping production blast holessoastofind borehole stability problems. A total of 298 blast holes were filmed. There were eight types of stability problems identified in the blast holes. These are shear zone, loose rock, cave, crack, deformation, stone jammed, spalling and rock breakage. Among these problems, deformation and crack were the most common ones in all the ore bodies. In addition, instability problem in the blast holes were higher around the rings which were blasted last. Further it has been found that the area which is affected by more seismic responses is the same as the one where several boreholes were re-drilled or sheared.

  • 6.
    Ghosh, Rajib
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Zhang, Zongxian
    University Centre in Svalbard.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Borehole instability in Malmberget Underground Mine2015In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 48, no 4, p. 1731-1736Article in journal (Refereed)
  • 7. Hansson, Håkan
    et al.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Utvärdering av två-lagers cylinderförsök: experiment och FEM-simulering2010Report (Other academic)
    Abstract [en]

    An experimental study regarding a model material's ability to absorb energy during blasting has been carried out. The tests were performed using copper pipes with a wall thickness of 5,0 mm and an inner diameter of 100 mm. An inner layer of mortar was cured inside the copper pipes, reducing the inner diameter to 44,5 mm. The plastic explosive NSP 711 was used for the tests, which from our viewpoint is considered to detonate ideally. The displacements of the copper pipe were registered at several locations during the tests.FEM simulations were conducted based on the test set up, and the calculated displacements of the copper pipe were compared with the displacements obtained from the tests. The input data for grout and copper in the simulations were adjusted until a fair agreement was obtained between simulation results and test data. The simulations are thereafter used to estimate the transmitted energy to the mortar and the copper pipe.

  • 8. Johansson, Daniel
    et al.
    Ouchterlony, Finn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Edin, J.
    Luleå tekniska universitet.
    Martinsson, L.
    Luleå tekniska universitet.
    Nyberg, Ulf
    Blasting against confinement, fragmentation and compaction in model scale2008In: MassMin 2008: Proceedings of the 5th International Conference and Exhibition on Mass Mining, Lulea, Sweden 9-11 June 2008 / [ed] Håkan Schunnesson; Erling Nordlund, Luleå: Luleå tekniska universitet, 2008, p. 681-690Conference paper (Refereed)
  • 9.
    Johansson, Daniel
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Ouchterlony, Finn
    Nyberg, Ulf
    Blasting against aggregate confinement: fragmentation and swelling in model scale2007In: Fourth EFEE World Conference on Explosives and Blasting: [Vienna Conference Proceedings 2007] / [ed] Peter Moser, European Federation of Explosives Engineers , 2007, p. 13-26Conference paper (Refereed)
    Abstract [en]

    Sub-level caving (SLC) is classified as a mass mining method and there is increasing interest in its application world wide and under a very wide range of geotechnical environments. In terms of flow, the caved rock or debris at the interface first acts as a wave trap, which may reduce the fragmentation. Model scale tests are being made to understand the mechanisms of rock breakage and therefore fragmentation under relatively confined conditions. To minimize geometrical and geological effects, tests were conducted mainly on cylinders of magnetic mortar of size Ø140×280 mm and PETN cord with different strengths was used as explosive in a center hole, giving a specific charge between 0,2 and 2,6 kg/m3. The size distributions of the blasted material and the aggregate as well as the swelling of the cylinders have been measured. For the latter, a freezing-slicing method was developed. The results show that the confinement results in fragmentation being coarser when compared to that from free cylinders, and that the properties of the debris have a strong influence on the fragmentation and the swelling.

  • 10. Johansson, Daniel
    et al.
    Ouchterlony, Finn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Modellförsök med sprängning mot rasmassor: inverkan på styckefall och svällning2007In: Bergsprängningskommittén : diskussionsmöte BK 2007: protokoll från Bergsprängningskommitténs diskussionsmöte i Stockholm den 13 mars 2007, 2007, p. 105-120Conference paper (Other academic)
  • 11.
    Nordlund, Erling
    et al.
    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.
    Saiang, David
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Shirzadegan, Shahin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Westblom, Magnus
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Zhang, Ping
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Marklund, P-I
    Boliden Mineral AB.
    Sandström, D.
    Boliden Mineral AB.
    Malmgren, Lars
    Samverkan mellan bergförstärkningssystem och bergmassa2011In: Bergmekanikdag 2011: Föredrag, Stiftelsen bergteknisk forskning - Befo , 2011, p. 19-28Conference paper (Other academic)
  • 12.
    Nordlund, Erling
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Saiang, David
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Zhang, Ping
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Basarir, Hakan
    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.
    Shirzaegan, S.
    Luleå tekniska universitet.
    Westblom, Magnus
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Malmgren, Lars
    Marklund, P-I
    Boliden Mineral AB.
    Nordqvist, A.
    LKAB.
    Sandström, D.
    Boliden Mineral AB.
    Rock support system in interaction with the rock2011Conference paper (Other academic)
  • 13.
    Nyberg, Ulf
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Arvanitidis, Ioannis
    Olsson, Mats
    Ouchterlony, Finn
    Large size cylinder expansion tests on ANFO and gassed bulk emulsion explosives2003In: Explosives and blasting technique: proceedings of the EFEE Second World Conference on Explosives and Blasting Technique / [ed] R. Holmberg, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 2003, p. 181-191Conference paper (Refereed)
  • 14.
    Nyberg, Ulf
    et al.
    SveBeFo.
    Arvanitidis, Ioannis
    Ouchterlony, Finn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Olsson, Mats
    Cylinder expansion tests on reference explosives from production2002Report (Other academic)
  • 15. Nyberg, Ulf
    et al.
    Esen, Sedat
    Luleå tekniska universitet.
    Bergman, Peter
    Boliden Mineral AB.
    Ouchterlony, Finn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Uppföljning av styckefallet i salva 4141-2 i Aitikgruvan2006Report (Other academic)
  • 16.
    Nyberg, Ulf
    et al.
    SveBeFo.
    Fjellborg, Stig
    Olsson, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Ouchterlony, Finn
    Bedömning av sprängskador i ortkontur: vibrationsmätningar, skadeprognoser och sprickkartering i magnetitmalm och gråberg2000Report (Other academic)
  • 17.
    Nyberg, Ulf
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Harefjord, Leif
    Bergman, Björn
    Christiansson, Rolf
    Monitoring of vibrations during blasting of the APSE tunnel2005Report (Other academic)
  • 18.
    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.

  • 19.
    Nyberg, Ulf
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Olsson, Mats
    Ouchterlony, Finn
    Bestämning av Gurney- och detonationsenergin för emulsionssprängämnen med hjälp av cylinderförsök2009Report (Other academic)
    Abstract [en]

    Nine cylinder tests for emulsion explosives in expanding Ø100/110 mm copper tubes are reported. The explosive recipe for pure emulsion respectively for blend of ANFO/AN-prills was formulated specifically for Swebrec:s test program. The primary goal was to verify earlier determinations of the explosive energy. In addition, recordings from streak camera and data from contact pins was evaluated for copper tubes 350 mm long and Ø60/72 mm filled with FOX12/TNT. The latter was cooperation between FOI- Swedish Defence Research Agency and Swebrec- Swedish Blasting Research Centre.The Gurney energy was calculated when the expansion velocity was almost constant i.e. at a volume of the explosives gases 7-8 times the original explosive volume. Expansion data for each explosive were fitted to the JWL- equation with help of a Matlab routine and the estimated JWL-parameters were used to calculate the detonation energy.Our conclusions, based on the measured data with Ø100/110 mm tubes are that there is no significant difference in the Gurney energy for the three explosives. The detonation energy increases somewhat with addition of AN/AN-prills, but the difference is small compared to the data scatter. This was basically the same results as for the earlier tests with similar emulsion explosives.The aim of the separate technique study with FOX12/TNT was to verify the contact pin data against streak camera data for two tests. The comparison shows that contact pin radial velocity data for the two shots agree well and that the streak recordings agree fairly well. The comparison of the two techniques shows that streak recordings give a 3-7 % lower radial velocity after approximately 30 μs. The two techniques can be a complement to each other.

  • 20.
    Olsson, Mats
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Fjellborg, Stig
    LKAB.
    Kontrollerad sönderbrytning vid skivrassprängning: inledande försök2009Report (Other academic)
    Abstract [en]

    This report describes some tests made in order to examine a number of important factors in sublevel caving. Among these factors were back-break, influence of a neighbour hole, rock movements in caving and the effect of compacted rock.The tests with back-break and influence of neighbour holes were performed in the abandoned open pit at Svappavaara, some 50 km south of Kiruna. The tests area was 100 m long with bench heights of 10-20 m. The area was divided into 4 test areas. Some 40 blast holes were drilled with a hole dimension of 115 mm and with a burden of 3 m. The 1st test area contained a sublevel drill layout of 8 holes but drilled downwards. The purpose here was to study the influence of a neighbour hole and back-break. The 2nd area consisted of a number of parallel vertical holes in two groups with different burdens. In the 3rd area three holes were drilled in a way to test the maximum spacing for breaking rock. The 4th area was again a test of the sublevel caving drill plan. The holes were charged with LKAB's standard emulsion KimuluxR 0500 for sublevel caving work.Measurements of the straightness of the holes were done. The detonation velocity was measured and the four rounds were high-speed filmed. The position of the bench front before and after blasting was measured with a stereo photogrammetric technique. The geology and the deviation of the holes were worse than expected and had an influence on the results. The maximum back-break occurred at tests with sublevel caving. It was possible to increase the burden to 3,5 m but with a coarser fragmentation. Furthermore fully charged 115 mm holes with a spacing of 7 m had no problem to break the burden. The velocity of the blasted front was measured to 13-21 m/s. Tests simulating sublevel caving were performed in the Kiruna mine by blasting a number of 64 mm and 115 mm holes drilled parallel with drift walls at different burdens. The walls were unconfined, i.e. free to move. A new method was invented consisting of an impact rod sliding in a measuring pipe. The impact rod is attached to the wall and when the wall is blasted the rod starts to move in the pipe and cuts a number of equally spaced coaxial cables fixed in the pipe. The velocity of the blasted wall was in this way measured with very good accuracy. The velocity of the wall depends upon the amount of explosive and the burden and varies in these tests from 7 m/s (for a 115 mm hole with a burden of 3,3m) up to 45 m/s (for a 64 mm hole and with a burden of 0,52 m).The drift wall tests series will continue with unconfined shots and shots were the drift wall is confined by caving debris.

  • 21.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Bergman, P.
    Boliden Mineral AB.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Fragmentation in production rounds and mill through-put in the Aitik copper mine: a summary of development projects 2002-20092013In: Rock Fragmentation by Blasting, FRAGBLAST 10: Proceedings of the 10th International Symposium on Rock Fragmentation by Blasting / [ed] Pradeep K. Singh; Amalendu Sinha, Boca Raton, Fla.: CRC Press/Balkema , 2013, p. 117-128Conference paper (Refereed)
    Abstract [en]

    The Boliden Mineral Aitik mine has worked to increase the through-put in the primary AG mills together with Swebrec. A raised specific charge from 0.9 to 1.3 kg/m3 raised the throughput by nearly 7%. This was implemented in 2009. For two rounds Swebrec has mapped joints from 3D images to determine the rock mass factor and combined Split Desktop measurements with sieving of muck-pile samples to get the sieving curve of the muck pile, based on the Swebrec function. For a 3rd round such curves were fed into a crusher model and results compared with Online data. The crusher product can affect the mills by three mechanisms; a harder blasting that i) produces more fines that may pass the mill intact, ii) gives a finer crusher product which takes a shorter time to grind iii) increases the amount of larger stones that pass the crusher intact but have an increased grindability. All three must contribute to the increased mill through-put.

  • 22.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Moser, Peter
    Nyberg, Ulf
    Arvanitidis, Ioannis
    Charakterisierung der Leistungsfähigkeit von ANFO- und Emulsionssprengstoffen mit Hilfe von großen Zylinderexpansionsversuchen2003In: Berg- und Huttenmännische Monatshefte (BHM), ISSN 0005-8912, E-ISSN 1613-7531, Vol. 148, no 6, p. 231-238Article in journal (Refereed)
    Abstract [en]

    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.

  • 23. Ouchterlony, Finn
    et al.
    Nie, Shulin
    SveBeFo.
    Nyberg, Ulf
    SveBeFo.
    Deng, Junhua
    SveBeFo.
    Monitoring of large open cut rounds by VOD, PPV and gas pressure measure­ments1996In: Rock Fragmentation by Blasting: proceedings of the Fifth International Symposium on Rock Fragmentation by Blasting - FRAGBLAST-5, Montreal, Quebec, Canada, 25 - 29 August 1996 / [ed] Bibhu Mohanty, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1996, p. 167-176Conference paper (Refereed)
  • 24. Ouchterlony, Finn
    et al.
    Nie, Shulin
    SveBeFo.
    Nyberg, Ulf
    SveBeFo.
    Deng, Junhua
    SveBeFo.
    Monitoring of large open cut rounds by VOD, PPV and gas pressure measure­ments1997In: Fragblast, ISSN 1385-514X, E-ISSN 1744-4977, Vol. 1, no 1, p. 3-25Article in journal (Refereed)
  • 25.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Bergman, Peter
    Boliden Mineral AB.
    Esen, Sedat
    Metso Minerals Process Technology.
    Monitoring the blast fragmentation of Boliden Mineral's Aitik mine2007In: Fourth EFEE World Conference on Explosives and Blasting: [Vienna Conference Proceedings 2007] / [ed] Peter Moser, European Federation of Explosives Engineers , 2007, p. 47-62Conference paper (Refereed)
    Abstract [en]

    The Boliden Mineral's Aitik mine strives to increase the throughput of the primary mills, which requires a better understanding of the blast fragmentation. This article describes detailed fragmentation monitoring work of round, 4141-2. Structural mapping and core drilling, drilling and charging monitoring, VOD-measurements and blast filming were made. The blast fragmentation on the trucks was monitored automatically with Split Online and manually with Split Desktop. Four barrel samples were sieved to obtain the fines part of the fragment size distribution. The Desktop images had to be edited to avoid fragment splitting and merging errors. The Online images contained errors of many kinds and seem to be sensitive to light conditions; measured fragmentation during night-time was about 50% finer than during daytime. The data appear to be log-normally distributed. The average fragment size x50 became either 171±108 mm (Online) or 458±175 mm (Desktop) and the correlation between the online and desktop data is virtually non-existent. Suggestions are also made how to improve the quality of the data. At the end, a complete fragment size distribution down to 0,2 mm for round 4141-2 is constructed by the use of the x50- and x80-values from Split Online and Desktop and the sieved samples, using the Swebrec function.

  • 26. Ouchterlony, Finn
    et al.
    Nyberg, Ulf
    SveBeFo.
    Olsson, Mats
    The WP3 fully monitored blasts at Nordkalk's Klinthagen quarry2002Report (Other academic)
  • 27.
    Ouchterlony, Finn
    et al.
    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.
    Olsson, Mats
    Andersson, P-O
    NCC Roads.
    Nyqvist, Linus
    NCC Roads.
    Vikström, Kristina
    NCC Roads.
    Bida, Jan
    Bergskolan.
    Svedensten, Per
    Sandvik Minng and Construction.
    Fragmenteringsförsök vid NCC:s täkt i långåsen, effekten av höjd specifikladdning eller elektronik upptändning2010In: Protokoll från Bergsprängningskommitténs diskussionsmöte i Älvsjö den 9 mars 2010, 2010, p. 118-154Conference paper (Other academic)
  • 28.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Olsson, Mats
    Bergquist, Ingvar
    Granlund, Lars
    Grind, Henrik
    The energy balance of production blasts at Nordkalk's Klinthagen quarry2003In: Explosives and blasting technique: proceedings of the EFEE Second World Conference on Explosives and Blasting Technique / [ed] R. Holmberg, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 2003, p. 193-203Conference paper (Refereed)
  • 29.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Olsson, Mats
    Bergquist, Ingvar
    Granlund, Lars
    Grind, Henrik
    Vart tar sprängämnesenergin i sprängsalvor vägen?2004In: Bergsprängningskommittén Diskussionsmöte BK 2004, Bergsprängningskommittén , 2004, p. 85-103Conference paper (Other academic)
    Abstract [sv]

    Vid bergsprängning frigörs snabbt stora mängder kemiskt bunden energi, 3-4 MJ per kg sprängämne. En del stannar som förluster i hålet och en del överförs till berget. Av den överförda energin nyttiggörs bara en del. Mätningar på fem produk¬tionssalvor hos Nordkalk Storugns visar hur energin kan fördelas. För att uppskatta förlusterna i hålet har ett nytt prov utvecklats, cylinderexpansions¬provet. I det sprängs laddade kopparrör och rörväggens hastighet mäts. Proven visar att ANFO förmår överföra 40-50 % av sin energi till radiellt expansionsarbete medan bulkemulsionen hos Nordkalk, Titan 6080 överför 60-70 %.Mätningarna hos Nordkalk visar att sprickytan ökar från 3-6 m2/m3 in-situ till 20-23 m2/m3 i salvhögen, motsvarande en fragmenteringsenergi på endast 0,1-0,2 % av sprängämnesenergin. Kasthastigheter om ca 10 m/s ger en kinetisk energi hos det lossbrutna berget på 3-12 %. Svängningshastighetsmätningarna ger lika lite seismisk energi. Tillsammans uppgår de tre energidelarna alltså till högst 25 % jämfört med i cylinderexpansionsprovet uppmätta 60-70 %. Krossningsarbete närmast borrhålet utgör förmodligen en stor del av mellanskillnaden

  • 30.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nyberg, Ulf
    Olsson, Mats
    Bergqvist, Ingvar
    Dyno Nobel Europe AB.
    Granlund, Lars
    Dyno Nobel Europe AB.
    Grind, Henrik
    Nordkalk AB.
    Where does the explosive energy in rock blasting rounds go?2004In: Science and Technology of Energetic Materials, ISSN 1347-9466, Vol. 65, no 2, p. 54-63Article in journal (Refereed)
    Abstract [en]

    The energy partitioning of limestone production blasts has been measured under well controlled conditions; from rock properties determination, structural mapping and monitoring of drilling and charging, to VOD, 3D accelerometer and bench face movement measurements during the blast to post-blast fragment size measurements. The efficiency of the transfer of energy from the charges to the surrounding rock has been estimated by introducing a new explosives test, the cylinder expansion test, which is discussed to be-gin with. Hereby in-hole losses, seismic energy, kinetic energy of throw and fragmentation energy have been calculated. For the AN doped gassed bulk emulsion used in the quarry, it is estimated that 60-70 % of the explosive energy is transmitted to the rock, that the seismic and kinetic energy terms both amount to roughly 3-12 % and the fragmentation energy to less than 1-2 %. One candidate for the remaining losses, which are larger than the other three terms together, is the crushing of the blast-hole region. A rough estimate for the energy partitioning in bench blasting rounds is finally given.

  • 31.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Olsson, Mats
    Nyberg, Ulf
    Andersson, Peter
    Gustavsson, Lennart
    Constructing the fragment size distribution of a bench blasting round, using the new Swebrec function2006In: Proceedings of the 8th International Conference on Rock Fragmentation by Blasting, Santiago: Editec , 2006, p. 332-344Conference paper (Refereed)
    Abstract [en]

    The blasting at the Vändle aggregate quarry has been investigated in order to predict the effect of the specific charge on fragmentation and to assess the contribution of blasting and primary crushing to the -32 mm fines. Two 25000 ton blasts divided into halves were monitored. Each half had an expanded or a shrunken pattern in order to lower or raise the specific charge. A normal round uses Ø90 mm drill-holes on a 34 m pattern with a gassed bulk emulsion blend with 20-25 % of AN prills. The test rounds lay directly behind each other, with a shrunken pattern behind an expanded one and vice versa to minimize the influence of geology.From the muck piles, four test piles of about 500 tons were extracted and photographed for image processing. About a quarter of each was sieved in four steps and fines samples taken. The material was replaced and the whole pile fed to the primary crusher while measuring the effect and the fines produced. Crushability and grindability data were measured.All lab samples and crushing test samples follow the new Swebrec distribution extremely well. The fragmentation size distribution of the muck piles is constructed using the sieving data and the lab samples, conforming to the Swebrec function. Image analysis gives a fragmentation curve with a distinctly different character. Of the total of 28 % of -32 mm fines after primary crushing, blasting and crushing contribute about half each. Based on these data a set of design curves are constructed that allow the prediction of how any given fraction changes when the specific charge in the round is changed.

  • 32.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Olsson, Mats
    Nyberg, Ulf
    Potts, Greg
    Luleå tekniska universitet.
    Andersson, Peter
    Swerock AB, Västerås.
    Gustavsson, Lennart
    Swerock AB.
    Fragmenteringsförsöken i Vändle och designkurvor för ändring av specifik laddning2006In: Bergsprängningskommittén Diskussionsmöte BK 2006, Bergsprängningskommittén , 2006, p. 97-122Conference paper (Other academic)
    Abstract [sv]

    Sprängförsök har utförts vid Swerock AB:s Vändletäkt för att ta fram en beskrivning av hur sprängningsresultatet kan påverkas så att önskat styckefall in i förkrossen erhålls. Resultatet blev bl a designkurvor som beskriver hur styckefallsfördelningen ändras när den specifika laddningen ändras. I två produktionssalvor krymptes hålmönstret i ena halvan och glesades ut i den andra med användning av befintlig borrutrustning. Uppföljningen bestod av profil- och hålinmätning, mätning av laddad mängd och VOD samt styckefallsmätningar mm. Ur salvorna togs fyra provhögar och ca 100 ton ur varje siktades och utvärderades med bildanalys. Materialet lades sedan tillbaka och provhögarna krossades medan krossningsenergin mättes. Ur siktdata kunde styckefalls-fördelningarna konstrueras med hjälp av Swebrecfunktionen. Några slutsatser är att - Styckefallet liknar bergmaterialkurva nr 62 - Sprängningen och förkrossen bidrar med lika mycket var av producerad bärlagerfraktion - Skutandelen kan uppskattas med bildanalysen men styckefallskurvorna från bildanalysen har annan form än siktkurvorna - Siktkurvorna bedöms vara tillförlitligare

  • 33.
    Ouchterlony, Finn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Olsson, Mats
    Nyberg, Ulf
    Potts, Greg
    Luleå tekniska universitet.
    Andersson, Peter
    Swerock AB, Västerås.
    Gustavsson, Lennart
    Swerock AB, Västerås.
    Optimal fragmentering i krosstäkter: fältförsök i Vändletäkten2003Report (Other academic)
  • 34.
    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.

  • 35.
    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.

  • 36.
    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.

  • 37.
    Shirzadegan, Shahin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordlund, Erling
    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.
    Zhang, Ping
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Malmgren, Lars
    Mining Technology R and D, LKAB Kiruna Mine.
    Rock support subjected to dynamic loading: Field testing of ground support using simulated rockburst2011In: Harmonising rock engineering and the environment: proceedings of the 12th ISRM International Congress on Rock Mechanics, Beijing, October 18 - 21, 2011 / [ed] Qihu Qian; Yingxin Zhou, Leiden: CRC Press/Balkema , 2011, p. 1269-1273Conference paper (Refereed)
    Abstract [en]

    Increasing the mining depth at LKABs Kiirunavaara mine located in the northern part of Sweden is leading to higher stress magnitudes, resulting in increased seismic activity and more rockburst damage. The effectiveness of various ground support systems under dynamic loading conditions has therefore become of prime interest to LKAB for successful and safe mining at deep levels. Therefore, a series of rockburst simulations will be conducted, using explosives to generate the dynamic load, on a number of support systems. This paper covers the results from the first trial test called Zero test-1. The test included ground motion measurements with a number of accelerometers, fracture investigation, ground and support motion imaging, as well as the deformation measurements. The methodology used to simulate rockbursts is discussed and the issues met in these tests are also addressed for further improvement.

  • 38.
    Shirzadegan, Shahin
    et al.
    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.
    Zhang, Ping
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordlund, Erling
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Malmgren, Lars
    Mining Technology R and D, LKAB Kiruna Mine.
    Nordqvist, Anders
    LKAB.
    Andersson, Ulf Bertil
    LKAB.
    Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Test 12013Report (Other academic)
  • 39.
    Shirzadegan, Shahin
    et al.
    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.
    Zhang, Ping
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordlund, Erling
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Malmgren, Lars
    LKAB Research and Development.
    Nordqvist, Anders
    LKAB.
    Andersson, Ulf Bertil
    LKAB.
    Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Tests 4 & 52013Report (Other academic)
  • 40.
    Shirzadegan, Shahin
    et al.
    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.
    Zhang, Ping
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordlund, Erling
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Malmgren, Lars
    Mining Technology R and D, LKAB Kiruna Mine.
    Nordqvist, Anders
    LKAB.
    Andersson, Ulf Bertil
    LKAB.
    Large-scale dynamic testing of rock support system at the Kiirunavaara underground mine: Tests 2 & 32013Report (Other academic)
  • 41.
    Shirzadegan, Shahin
    et al.
    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.
    Zhang, Ping
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordlund, Erling
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Malmgren, Lars
    Mining Technology R and D, LKAB Kiruna Mine.
    Töyrä, Jimmy
    LKAB.
    Nordqvist, Anders
    Andersson, Ulf Bertil
    LKAB.
    Large-scale dynamic testing of ground support system at the Kiirunavaara underground mine: Tests 6&72013Report (Other academic)
  • 42.
    Sjöberg, Jonny
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Schill, Mikael
    DYNAmore Nordic AB, Linköping.
    Hilding, Daniel
    DYNAmore Nordic AB, Linköping.
    Yi, Changping
    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.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Computer simulations of blasting with precise initiation2012Conference paper (Refereed)
    Abstract [en]

    Using blasting caps with electronic delay units, it has become possible to employ wave superposition in rock blasting. This paper presents computer simulations to investigate the hypothesis that fragmentation is improved in areas between blast holes where the tensile waves meet, overlap and interact. In this study, a numerical methodology using the code LS-DYNA was developed. LS-DYNA is a commercially available multi-purpose finite-element code, which is well suited to various types of dynamic modeling. Two different element formulations were used — Euler formulation in, and close to, the blast hole, and Lagrange formulation in the rock volume farther from the blast hole. The models used have a resolution (element size) of 50 mm and comprise approximately 20 million elements. Single and dual blast hole configurations have been studied, and a methodology to calculate possible fragmentation based on model interpretation was developed. The results showed that the amount of explosives and the blast hole spacing had the largest effect on fragmentation. The effect of varying delay times was small and local, implying that a significant increase in fragmentation should not be expected through wave superposition.

  • 43. Tesarik, D.R.
    et al.
    Hustrulid, W.A.
    Nyberg, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Assessment and application of a single-charge blast test at the Kiruna mine, Sweden2011In: Blasting and Fragmentation, ISSN 1937-6359, Vol. 5, no 1, p. 47-72Article in journal (Refereed)
    Abstract [sv]

    Partikelhastighet (PPV) och avståndsmätningar utförda av svenska forskare presenteras för enskottsladdningar i järnmalm i Kiruna gruvan i norra Sverige. De används tillsammans med teoretiska PPV-värden som beräknats med hjälp av en formel baserad på hydrodynamik för att bestämma skadornas omfattning orsakas av en enda laddning. Denna ekvation, som relaterar PPV till explosiva egenskaper, laddningsgeometri och avstånd från en laddning, tillämpades sedan på en laddning av olika geometri som användes i ortdrivning. En jämförelse mellan beräknade och uppmätta PPV tyder på att strosshålen sannolikt skada läget för hjälparhålen, och att hjälparhålen ger skador där konturhålen sitter. Den praktiska konsekvensen är att typiska skadeberäkningar baserade på mätningar utförda i oskadat berg är konservativa. Detta tyder på att även när begränsningar av sprängskador inte tillämpas för drivning (dvs konturhålen är fulladdade), kan den resulterande skadan bli mindre än förväntat på grund av den vågdämpande effekten som det förspräckta berget utgör. På grund av den dämpande effekten, kommer dålig kontroll av kontursprängning att till vis del vara sälvkorrigerande. Det måste dock starkt betonas att väl en utvecklad utformning av sprängning med kontroll av konturen är mycket fördelaktig i förhållande till både ekonomiska och säkerhetsmässiga aspekter.

  • 44.
    Wimmer, Matthias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordqvist, Anders A.
    Mining Technology R and D, LKAB Kiruna Mine.
    Ouchterlony, Finn
    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.
    Furtney, Jason
    Itasca Consulting Group.
    Burden movement in confined drift wall blasting tests studied at the LKAB Kiruna SLC mine2012In: Rock Fragmentation by Blasting, FRAGBLAST 10: Proceedings of the 10th International Symposium on Rock Fragmentation by Blasting / [ed] Pradeep K. Singh; Amalendu Sinha, Boca Raton, Fla.: CRC Press/Balkema , 2012, p. 373-383Conference paper (Refereed)
    Abstract [en]

    Blasting in SLC (sublevel caving) takes place in a semi-confined situation. Blasted material swells while the caved material compacts, and also, to a lesser extent, fills parts of the void volume of the production drift. Several analytical and empirical models have been developed in the past. However, understanding of the interaction of semi-confined blasting conditions, SLC blast design and rock mass characteristics on rock breaking performance is rudimentary. Instrumentation of the blasted burden with various sensors and study of the dynamics of burden movement against confinement is therefore important. Such measurements are very scarce and thus different systems have been tested both in laboratory and in the field. Main focus was thereby the development of measuring equipment that could be scaled up to full-scale SLC blasting and installed behind the rings. In the field tests, blastholes were drilled in a pillar, parallel to a cross cut drift in the LKAB Kiruna SLC mine. The burden constraint was achieved either by filling the drift of 7.0 x 5.2 m (width x height) with rock masses or reinforcing the drift wall. The tests were instrumented with different redundant sensors, which were installed in holes drilled from a parallel cross cut. The most promising one was a concept, which combines the initial movement recorded by an accelerometer designed to minimize zero-shift with the final displacement recorded by a fibre photoelectric sensor (‘fibre-optic zebra gauge’). For the filled drift wall blasting test the maximum velocity varied between 16 - 32 m/s with a compaction in the range of 4 - 5 %. A gap was verified to exist between the intact pillar and the blasted material. By comparison, the velocity for the unconfined situation yielded a considerably increased velocity (42 - 47 m/s). In addition, ‘Blo-Up’, a component within the Hybrid Stress Blast Model (HSBM), was used to model the blasting results. The ob-jective was to show that reasonable predictions of fragmentation and burden movement under confined conditions can be made. An unconfined reference experiment was used to calibrate Blo-Up and forward predictions of the confined case were made. In both cases, Blo-Up accurately reproduced the burden velocity and displacement observed in the experiments. The suggested measurement concept could be used for further measurements of confined burden movement in filled drift wall blasting tests and under controlled situations. As mentioned the final objective is instrumentation of the burden in SLC production rings.

  • 45.
    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.
    Scattering of SH-waves by a shallow circular lined tunnel with an imperfect interface2016In: Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction / [ed] E. Nordlund, T.H. Jones and A. Eitzenberger (eds), 2016Conference paper (Refereed)
    Abstract [en]

    The analytic solutions for the dynamic response of a shallow circular lined tunnel with an imperfectly bonded interface subjected to plane SH-waves are presented in the paper. Complex variable method was used and the imperfect interface was modelled with a linear spring model. The case that the rock is harder than the liner was investigated. The effects of the contact stiffness of the interface, the incident angle, the frequency of the incident wave and the depth of the tunnel were investigated. The results indicate when the frequency of incident waves is low, the variation of contact stiffness of the imperfect interface has a slight effect on the distribution of dynamic stress concentration factor (DSCF) in the rock mass but there is a significant effect on the distribution of DSCF in the liner. When the frequency of incident waves is high, the distribution of DSCF is complicated in the rock mass and in the liner. The variation of the depth of tunnel leads to the cyclical variation of DSCF. The incident angle significantly affects the distribution and value of DSCF. The phenomenon of resonance scattering can be observed when the bond of the interface is extremely weak

  • 46.
    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.

  • 47.
    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.
    Sjöberg, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Numerical simulation for the influence of delay time on the rock fragmentation2013In: Rock Fragmentation by Blasting, FRAGBLAST 10: Proceedings of the 10th International Symposium on Rock Fragmentation by Blasting / [ed] Pradeep K. Singh; Amalendu Sinha, Boca Raton, Fla.: CRC Press/Balkema , 2013, p. 213-220Conference paper (Refereed)
    Abstract [en]

    With the application of electronic detonators and with short delay times, it may be possible to achieve improved fragmentation through stress wave superposition. This hypothesis was studied through a series of small scale laboratory tests. The results from these tests have subsequently been modeled using the numerical FEM code LS-DYNA and the RHT (Riedel-Hiermaier-Thoma) material model, applying a newly developed methodology for three-dimensional computer simulation of blasting. This work also involved simulating initial damage to the rock through previous blasting, and analyzing the resulting effects. The effect of different delay times showed that through a properly chosen delay time, improved fragmentation could be inferred. Moreover, the initial damage (from the previous row) clearly affected the fragmentation; however, the results indicated that longer delay times (in which the stress wave would have passed the boreholes) also resulted in improved fragmentation, implying that stress wave superposition may not be the primary factor governing fragmentation

  • 48.
    Yi, Changping
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Lu, Wenbo
    Rock Mechanics in Hydraulic Structural Engineering, Ministry of Education.
    Zhang, Ping
    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.
    Effect of imperfect interface on the dynamic response of a circular lined tunnel impacted by plane P-waves2016In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 51, p. 68-74Article in journal (Refereed)
    Abstract [en]

    A theoretical method for studying the dynamic response of a circular lined tunnel with an imperfectly bonded interface subjected to plane P-waves is presented in the paper. The wave function expansion method was used and the imperfect interface was modeled with a spring model. Two cases were discussed in the paper. In the first case rock is harder than the lining and vice-versa in the second case. The results indicated that the variation in the stiffness of the interface has much influence on the distribution of dynamic stress concentration factors (DSCF) in the rock and the lining. The imperfection of the interface has a more noticeable influence on the DSCF in the rock mass and the lining at high frequency incident wave's scenario than low frequency incident wave's scenario. The resonance scattering phenomena can be observed when the bond is extremely weak. Limiting cases were considered and a good agreement with the solutions available in the literature was obtained.

  • 49.
    Yi, Changping
    et al.
    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.
    Johansson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Parameter Determination of an Ignition and Growth Model from Emulsion Explosive Tests2015In: 11th International Symposium on Rock Fragmentation by Blasting: FragBlast11, Carlton VIC: The Australasian Institute of Mining and Metallurgy, 2015, p. 585-589Conference paper (Refereed)
    Abstract [en]

    Emulsion explosives are a common industrial explosive and have a non-ideal detonation behaviour. The detonation performance for a given product changes with the charge diameter, ground conditions, confinement and density. The burning process of an emulsion explosive has been modelled with an ignition and growth model in the LS-DYNA code. The parameters in the burning rate function are calibrated by the detonation velocities and the detonation front curvature radii from emulsion explosive tests. A Perl program was developed for an efficient estimation of the parameters, and the results show that the calibrated parameters can predict both detonation velocities and the detonation front curvatures.

  • 50.
    Yi, Changping
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Zhang, Ping
    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.
    Dynamic analysis for a circular lined tunnel with an imperfectly bonded interface impacted by plane SH-waves2014Conference paper (Refereed)
12 1 - 50 of 53
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