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- 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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| 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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