| 1. |
- Arvanitidis, Ioannis, et al.
(författare)
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Diameterns inverkan på detonationsegenskaperna hos emulsionssprängämne E682 i cylinderprovet
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 2. |
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Hirose, Sohichi, et al.
(författare)
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Dynamic fracture of star cracks
- 1993
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Ingår i: Proceedings of the Boundary Element Technology Conference. - : JASCOME. ; , s. 37-40
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Konferensbidrag (refereegranskat)
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| 7. |
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| 8. |
- Johansson, Daniel, et al.
(författare)
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Blasting against aggregate confinement, fragmentation and swelling inmodel scale : [Modellförsök med sprängning mot rasmassor: inverkan på styckefall och svällning]
- 2007
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Ingår i: Fourth EFEE World Conference on Explosives and Blasting. - : European Federation of Explosives Engineers. - 9780955029011 ; , s. 13-26
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 9. |
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| 10. |
- Johansson, Daniel, et al.
(författare)
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Dynamic blast compaction of some granular materials: small-scale tests and numerical modelling of a mining-related problem
- 2010
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Ingår i: International Journal of Mining and Mineral Engineering. - 1754-890X .- 1754-8918. ; 2:2, s. 79-100
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Tidskriftsartikel (refereegranskat)abstract
- Sub-Level Caving (SLC) is an important mass mining method, involving blasting of ore against granular material in the form of caving debris. The debris compaction due to blasting influences the caving process. Blasting tests were made on cylinders of magnetic mortar placed inside plastic cylinders and confined by packed granular material. By introducing the acoustic impedance between the mortar and the confining granular material, the compaction is found to depend on material, specific charge and physical properties of the debris with statistical analysis. The tests have shown to be a good input for numerical modelling of blast compaction.
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| 11. |
- Johansson, Daniel, et al.
(författare)
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Fragmentation in small-scale confined blasting
- 2011
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Ingår i: International Journal of Mining and Mineral Engineering. - 1754-890X .- 1754-8918. ; 3:1, s. 72-94
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Tidskriftsartikel (refereegranskat)abstract
- Design of sub-level blasting rounds and optimisation has become more important now when the sizes of the blasting rings get larger. Sufficient fragmentation is one of the key factors, and in confined blasting as in sub-level caving, this influences the mobilisation of the blasted ring. Model scale tests have been made to understand the mechanisms of rock breakage and therefore fragmentation under relatively confined conditions. By using the acoustic impedance between the blasted material and the confining debris, a relationship for fragmentation has been found depending on material, specific charge (powder factor) and physical properties of the debris. The results can be comparable with confined blasting in large scale.
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| 12. |
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| 13. |
- Johansson, Daniel, et al.
(författare)
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Shock wave interactions in rock blasting : the use of short delays to improve fragmentation in model-scale
- 2013
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Ingår i: Rock Mechanics and Rock Engineering. - : Springer Science and Business Media LLC. - 0723-2632 .- 1434-453X. ; 46:1, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- A series of detailed small-scale tests have been made to investigate the use of short delays to promote better fragmentation caused by shock wave interactions. The block design had a size of 650/660 × 205 × 300 mm (L × W × H) and two rows with five Ø 10-mm blastholes in each row. The spacing (S) and burden (B) were 110 and 70 mm, respectively, giving an S/B ratio of 1.6. The results showed no distinct differences or high improvements of the fragmentation when the delays were in the time range of interactions compared with no shock wave interactions. The decrease of x 50 (mean size) was around 20 % at a delay time ~1.1 ms/m burden compared with longer delays like 2 ms/m. A statistical analysis of the results has been made to evaluate the minimum at short delays and it is not significant
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| 14. |
- Lundborg, N., et al.
(författare)
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Fracture of rock
- 1975
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Ingår i: Tryckluft. - 0041-3739. ; :1, s. 28-34
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 15. |
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| 16. |
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| 17. |
- Minamide, Hideo, et al.
(författare)
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Site blasting test on parallel hole cut
- 1993
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Ingår i: Proceedings of the 25th Symposium on Rock Mechanics. - Tokyo : JSCE. ; , s. 391-395
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 18. |
- Nie, Shulin, et al.
(författare)
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Expansionsarbete av ett emulsionssprängämne i borrhål : mätning och simulering
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Att kunna styra sprängning och uppnå önskat resultat fordrar kunskaper om ett sprängämnes detonationsförlopp i borrhålet, dvs kunskaper om hur sprängämnets energi omsätts och överförs till berget. Dock är de kunskaperna inte lätt tillgängliga. T ex saknas det både mätrutiner och beräkningsmodeller för sprängämnens expansionsarbete i borrhål. Forskningen som beskrivs i rapporten omfattar både mätning och simulering. Ett forskningssprängämne har tillverkats och använts vid sprängning i granitblock och i en kalkstenspall. Förutom mätning av detonationshastighet, har LHM tekniken, som utvecklats på SveBeFo, använts för mätning av trycktidförloppet i spränghålet. Detta trycktidförlopp har sedan simulerats och jämförts med mätningarna. Som underlag för simuleringarna har sprängämnets egenskaper mätts och en brinnmodell för sprängämnet tagits fram. Försöken och simuleringarna har gett goda resultat. Rapporten beskriver tillverkning av sprängämnet och mätning av dess egenskaper, framtagning av sprängämnets brinnmodell, utveckling av mätuppställning för tillämpning av LHM tekniken i fältförsök, sprängningsförsök i granitblock och i kalkstenspall, simulering av fältförsöken samt resultaten från alla arbetsmomenten.
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| 19. |
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| 20. |
- Nyberg, Ulf, et al.
(författare)
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Bestämning av Gurney- och detonationsenergin för emulsionssprängämnen med hjälp av cylinderförsök
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 21. |
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| 23. |
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| 24. |
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| 25. |
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| 26. |
- Olsson, Mats, et al.
(författare)
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Ny skadezonformel för skonsam sprängning
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I Sverige används inom civilt bergbyggande en tabell för bedömning av skadezoner. Tabellen omfattar de vanligaste använda kontursprängämnena. Laddningskoncentrationen, omräknad till Dynamex-ekvivalenter, ligger till grund för bedömning av skadezonsdjupet. Tabellen har många begränsningar och är egentligen bara verifierad för Gurit och Prillit i 45 mm hål. Tabellen saknar också en definition av skada och säger tex. inget om vare sig hålsättning eller tändspridning men har trots dessa begränsningar varit ett praktiskt verktyg för design av skonsam sprängning. Ökad infrastruktuell utbyggnad innebär ofta bergarbeten i tätort med stora krav på begränsade skador på omgivningen. En ny tabell för bestämning av skador från sprängning behövs. Under ett antal år har forskning pågått på SveBeFo om sprickbildning i kvarstående berg från sprängning. Ett stort antal hål har sprängts och spricklängder i det kvarstående berget har undersökts. Frikoppling, hålavstånd, vatten i hål, initiering och sprängämnestyp är några av de parametrar som vi funnit som mest påverkar sprickutbredningen. Utifrån denna vetskap har en ny skadeformel tagits fram. Formeln utgår från våra uppmätta spricklängder i granit med ett antal kompensationsfaktorer för inverkan av hålavstånd, tändspridning, vatten i hål samt sprickighet. Rapporten beskriver bakgrunden till nuvarande skadezonstabell samt arbetet med den nya formeln samt hur den skall tillämpas. Hänsyn tas bl.a. till hur detonationshastigheten ändras med kopplingsgraden samt hur torra resp. våta hål påverkar detonationshastigheten. Innan den nya formeln kan tillämpas behövs ett antal fältprov. Ett förslag till försöksserie har diskuterats med Vägverket
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| 27. |
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| 28. |
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| 29. |
- Ouchterlony, Finn
(författare)
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A common form for fragment size distributions from blasting and a derivation of a generalized Kuznetsov's x50-equation
- 2009
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Ingår i: Rock Fragmentation by Blasting. - Boca raton, Fla. : CRC Press. - 9780415482967 ; , s. 199-208
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Konferensbidrag (refereegranskat)abstract
- A common form for fragment size distributions from blasting is derived from dimensional analysis. When gravity is neglected and the fragment shape is constant, one dimensionless parameter, Π s, remains. If the size distribution uses the quantities x/x max and x 50/x max the dependence on Π s becomes implicit. The Swebrec function has this preferred form. Π s depends essentially on specific charge, explosive energy, burden and rock strength and in a way, which reminds of the x 50-prediction equation of the Kuz-Ram model. A generalization of the x 50-equation is derived, which depends on whether the blasting is 2D or 3D, on the type of loading and on the material model. Test blast results are used to make the appropriate choice. One consequence is that the q-dependence of the x 50-equation changes with the way in which the blasting is done. Another is that the dependence of the Kuz-Ram uniformity index n on geometry only is questionable.
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Ouchterlony, Finn
(författare)
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Analysis of cracks related to rock fragmentation
- 1983
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Ingår i: Rock fracture mechanics. - Wien : Encyclopedia of Global Archaeology/Springer Verlag. ; , s. 31-67
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In the late 1960’s, fracture mechanics was seldom used in the analysis of rock fragmentation problems. Examplifying rock mechanics textbooks with Jaeger and Cook 1, they they do present Griffith’s theory of fracture and the term fracture mechanics in passing but not any applications to fragmentation.
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| 36. |
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| 41. |
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| 42. |
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| 43. |
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| 44. |
- Ouchterlony, Finn, et al.
(författare)
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Charakterisierung der Leistungsfähigkeit von ANFO- und Emulsionssprengstoffen mit Hilfe von großen Zylinderexpansionsversuchen
- 2003
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - 0005-8912 .- 1613-7531. ; 148:6, s. 231-238
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Tidskriftsartikel (refereegranskat)abstract
- Cylinder expansion tests have been made in order to measure the working capacity of commercial explosives under standardized but realistic conditions. Copper tubes, O 110/100 mm diameter, filled with ANFO or bulk emulsion explosives were detonated, the VOD and the tube wall expansion measured. From this the work capacity in terms of the Gurney energy EG, i.e. kinetic energy of tube and explosive gases, was calculated. Pure ANFO gave values of 1.6-1.9 MJ/kg, aluminised ANFO 2.5 MJ/kg and bulk emulsion 1.5-2.3 MJ/kg depending on the density. The explosive energy transfer is basically over at a volume expansion ratio of 5-10, but the aluminised ANFO keeps doing work much longer. Compared with their explosion energies however, the ANFO explosives transferred only 40-50 % of the available energy but the emulsion 60-70 % at normal densities. At densities above 1200 kg/m3, the VOD of the emulsions tends to drop off but the work capacity continues to increase. It is best described as a linearly increasing function with density. The case is finally made that the cylinder test is a better way to emulate rock-blasting conditions than the underwater test. It stops doing work at a relevant expansion ratio of the blast fumes and it has a reasonable balance between the different energies that accompany the blasting process. It can cope with charge sizes that are relevant for commercial explosives.
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| 45. |
- Ouchterlony, Finn, et al.
(författare)
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Constructing the fragment size distribution of a bench blasting round, using the new Swebrec function
- 2006
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Ingår i: Proceedings of the 8th International Conference on Rock Fragmentation by Blasting. - Santiago : Editec. ; , s. 332-344
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 46. |
- Ouchterlony, Finn, et al.
(författare)
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Crack lengths or blast damage from string emulsion and electronic detonators
- 2009
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Ingår i: Rock Fragmentation by Blasting. - Boca Raton, Fla : CRC Press. - 9780415482967 ; , s. 469-480
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Konferensbidrag (refereegranskat)abstract
- The crack patterns from contour blasting in Ø48-mm holes with Orica/Dyno Nobel SSE 0.35, 0.5 or 0.9 kg/m string emulsion charges in the Bårarp gneiss quarry have been studied, using both Nonel and electronic detonators. Some 24 blocks from behind half-casts were sawn and the cracks mapped. The crack lengths caused by simultaneously initiated SSE 0.35 kg/m or packaged Ø17 mm Dynotex 1 were practically the same. SSE 0.5 kg/m gave a roughly 50% increase in length. Nonel initiation resulted in longer cracks, as did water-filled holes. Nonel also gave a rougher remaining rock surface and frequently undetonated charges were found on the muck-pile. Earlier damage zone data were used to develop a suggested addendum to the present Swedish damage zone table. The use of simultaneously initiated decoupled light contour charges (q < 0.6 kg DxM/m) in dry holes has a damage suppressing effect compared to normal pyrotechnic initiation.
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| 47. |
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| 48. |
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| 49. |
- Ouchterlony, Finn, et al.
(författare)
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Die Swebrec-Funktion: Eine neue Korngrößenverteilungsfunktion und ihr praktischer Einsatz in der Sprengtechnik : [The swebrec function; a new fragment size distribution and its practical use for blast fragmentation]
- 2006
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - 0005-8912 .- 1613-7531. ; 151:10, s. 389-404
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents a new particle size distribution function, called the Swebrec function discovered during the work with the EU project Less Fines project. The function has just three parameters, with physical meaning, in its basic form. Yet it covers a size range of 23 orders in magnitude of fragment size and even more in an extended version. It has been tested on hundreds of sets of sieving data from different kinds of blasting and crushing of many different kinds of rock. The coefficient of determination r2 has in 95 % of the cases been better than 0.995, many times substantially better. Examples of such curve fits are given and the relation of the Swebrec function to traditional comminution concepts like the NBC concept, the t10 concept and the GGS-slope will be pointed out. Applications such as an extrapolation from the coarse range to the fines and vice versa will be shown and as will how the Swebrec function could be used to construct the fragment size distribution for muck piles from full-scale blasts, based on limited data. A final remark on how to implement the Swebrec distribution into fragmentation models will be given.
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| 50. |
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