This work analyses issues associated with the deteriorated blasting efficiency by the use of emulsion explosives in underground oil shale mines that utilise room and pillar mining methods. The problems were connected with the reduction in entry advance, shattering of pillar walls and falling of the roof. The aim of this study is to improve blasting efficiency that can guarantee a sufficient entry advance and secure stable conditions of the pillars and the immediate roof. The improved blasting pattern was successfully tested under in-situ conditions. It was demonstrated that the entry advance and the stability of the immediate roof and pillar walls were significantly enhanced as a result.
1. Ittner, H, Olsson, M., Johansson, D., Schunnesson, H. Multivariate evaluation of blast damage from emulsion explosives in tunnels excavated in crystalline rock. Tunn. Undergr. Space Technol., 2019, 85, 331‒339.
https://doi.org/10.1016/j.tust.2018.12.021
2. Cunningham, C. V. B., Goetzsche, A. F. The specification of blast damage limitations in tunnelling contracts. Tunn. Undergr. Space Technol., 1990, 5(3), 193‒198.
https://doi.org/10.1016/0886-7798(90)90006-6
3. Ivanova, R. Investigation on Fragmentation by Blasting: The influence of distorted blasthole patterns on fragmentation, roughness of the remaining bench face and blast damage behind it in model scale blasting. PhD thesis. Montanuniversitaet Leoben, Austria, 2015.
4. Persson, P.-A., Holmberg, R., Lee, J. Rock Blasting and Explosives Engineering. CRC Press, Florida, USA, 1993, 101, 106, 107.
5. Olsson, M., Ouchterlony, F. New Formula for Blast Induced Damage in the Remaining Rock. Swedish Rock Engineering Research, SveBeFo Rapport 65, 2003 (in Swedish).
6. Mertuszka, P., Cenian, B., Kramarczyk, B., Pytel, W. Influence of explosive charge diameter on the detonation velocity based on emulinit 7L and 8L bulk emulsion explosives. Cent. Eur. J. Energetic Mater., 2018, 15(2), 351‒363.
https://doi.org/10.22211/cejem/78090
7. Tete, A. D., Deshmukh, A. Y., Yerpude, R. R. Velocity of detonation (VOD) measurement techniques practical approach. Int. J. Eng. Technol., 2013, 2(3), 259265.
https://doi.org/10.14419/ijet.v2i3.1023
8. Chiappetta, R. F. Blast monitoring instrumentation and analysis techniques, with an emphasis on field application. Fragblast Int. J. Blasting Fragm., 1998, 2(1), 79‒122.
https://doi.org/10.1080/13855149809408880
9. Heit, A. An Investigation into the Parameters that Affect the Swell Factor Used in Volume and Design Calculations at Callide Open Cut Coal Mine. PhD thesis. University of Southern Queensland, 2011.
10. Maranda, A., Paszula, J. M., Drobysz, B. Research on detonation parameters of low density emulsion explosives modified by microballoons. CHEMIK, 2014, 68(1), 17‒22.
11. Reinsalu, E., Lüütre, E., Põldema, T., Väli, E. Long-term stability of pillars in an underground oil shale mine. Oil Shale, 2022, 39(2), 142–149.
https://doi.org/10.3176/oil.2022.2.04
12. Sabanov, S., Pastarus, J.-R., Nikitin, O., Väli, E. Risk assessment of seismic impact on the roof and pillars stability in Estonian underground. Estonian Journal of Engineering, 2008, 14(4), 325‒333.
https://doi.org/10.3176/eng.2008.4.04
13. Sokman, K., Kattai, V., Vaher, R., Systra, Y. J. Influence of tectonic dislocations on oil shale mining in the Estonia deposit. Oil Shale, 2008, 25(2S), 175‒187.
https://doi.org/10.3176/oil.2008.2S.09
14. Sabanov, S. Comparison of unconfined compressive strengths and acoustic emissions of Estonian oil shale and brittle rocks. Oil Shale, 2018, 35(1), 26‒38.
https://doi.org/10.3176/oil.2018.1.02
15. Sabanov, S., Madani, N., Mukhamedyarova, Z., Tussupbekov, Y. A risk analysis method for estimation of financial benefits of the existing mine ventilation system. Mining Metall. Explor., 2020, 37, 1137‒1149.
https://doi.org/10.1007/s42461-020-00232-7
16. Whittaker, B. N., Singh, R. N., Sun, G. Rock Fracture Mechanics: Principles, Design and Applications. Elsevier, Amsterdam, 1992.
17. Iverson, S. R., Hustrulid, W. A., Johnson, J. C. A New Perimeter Control Blast Design Concept for Underground Metal/Nonmetal Drifting Applications. DHHS (NIOSH) RI 9691, Report of Investigations/2013. Pittsburgh, PA * Spokane, WA, 2013.
18. Thorne, B. J., Hommert, P. J., Brown, B. Experimental and computational investigation of the fundamental mechanisms of cratering. In: The Third International Symposium on Rock Fragmentation by Blasting, Brisbane (Australia), 26‒31 August 1990. Fragblast’90, 1990, 117‒212.
19. Grady, D. E., Kipp, M. E. Continuum modelling of explosive fracture in oil shale. Int. J. Rock Mech. Min. Sci. Geomech. Abstr., 1980, 17(3), 147‒157.
https://doi.org/10.1016/0148-9062(80)91361-3
20. Taylor, L. M., Chen, E.-P., Kuszmaul, J. S. Microcrack-induced damage accumulation in brittle rock under dynamic loading. Comput. Methods Appl. Mech. Eng., 1986, 55(3), 301‒320.
https://doi.org/10.1016/0045-7825(86)90057-5
21. Kuszmaul, J. S. A new constitutive model for fragmentation of rock under dynamic loading. In: Second International Symposium on Rock Fragmentation by Blasting, Keystone, CO, USA, 23‒26 August 1987. Albuquerque, NM (USA), Sandia National Labs, 1987.
22. Kabwe, E. Velocity of detonation measurement and fragmentation analysis to evaluate blasting efficacy. J. Rock Mech. Geotech. Eng., 2018, 10(3), 523‒533.
https://doi.org/10.1016/j.jrmge.2017.12.003
23. An, H. M., Liu, H. Y., Han, H., Zheng, X., Wang, X. G. Hybrid finite-discrete element modelling of dynamic fracture and resultant fragment casting and muck-piling by rock blast. Comput. Geotech., 2017, 81, 322‒345.
https://doi.org/10.1016/j.compgeo.2016.09.007
24. Kanchibotla, S. S., Valery, W., Morrell, S. Modelling fines in blast fragmentation and its impact on crushing and grinding. In: Proceedings of Explo’99: A Conference on Rock Breaking, 7‒11 November 1999, Kalgoorlie, Australia. The Australasian Institute of Mining and Metallurgy, 1999, 137‒144.
25. Esen, S., Onederra, I., Bilgin, H. A. Modelling the size of the crushed zone around a blasthole. Int. J. Rock Mech. Min. Sci., 2003, 40(4), 485‒495.
https://doi.org/10.1016/S1365-1609(03)00018-2
26. Fickett, W., Davis, W. C. Detonation. University of California Press, Berkeley, 1979, 16, 54.
27. Cooper, P. W. Acceleration, formation, and flight of fragments. In: Explosives Engineering. Wiley-VCH, 1996, 385‒394.
28. Yang, J. H., Yao, C., Jiang, Q. H., Lu, W. B., Jiang, S. H. 2D numerical analysis of rock damage induced by dynamic in-situ stress redistribution and blast loading in underground blasting excavation. Tunn. Undergr. Space Technol., 2017, 70, 221‒232.
https://doi.org/10.1016/j.tust.2017.08.007
29. Cunningham, C. V. B. The Kuz-Ram model for prediction of fragmentation from blasting. In: Proceedings of the First International Symposium on Rock Fragmentation by Blasting (Holmberg, R., Rustan, A, eds.), August 23‒26, 1983, Lulea, Sweden, 2, 439‒453.
30. Kleine, T. A Mathematical Model of Rock Breakage by Blasting. PhD thesis. The University of Queensland, Australia, 1988.
31. Kleine, T., Cocker, A., Kavetsky, A. The development and implementation of a three dimensional model of blast fragmentation and damage. In: Proceedings of the Third International Symposium of Rock Fragmentation by Blasting, Brisbane (Australia), 26‒31 August 1990. The Australasian Institute of Mining and Metallurgy, Brisbane, Australia, 181‒187.
32. Kleine, T., Townson, P., Riihioja, K. Assessment and computer automated blast design. In: XXIV International Symposium on the Application of Computers and Operations Research in the Mineral Industries (Elbrond, J., Tang, X., eds.), Montreal, Canada, 31 Oct.‒3 Nov. 1993, 3, 351‒360.
https://doi.org/10.1007/978-3-322-83183-5_7
