Influence of deceleration intervals on the amplitudes of stress waves during the explosion of a system of borehole charges

Currently, many open pits there is a problem of substandard pieces of rock mass coming out after an explosion. Substandard pieces, most often, arise in the central part of the block, between the wells, due to poor development of this zone. This problem arises due to the fact that the amplitude of the stress waves from the explosion of charges in this area is much lower than near the wells. This article provides a brief overview of methods for calculating deceleration intervals; a model of a granite block with blastholes charged with ANFO was built; the simulation of the interference of voltage waves in the Ansys software package was carried out; the dependences of the voltages at the wave front on the time of the process are constructed, and the economic efficiency of the use of electronic and nonelectrical (NSI) initiation systems is calculated. Modeling showed that with the correct selection of the deceleration interval, it is possible to increase the amplitude of stress waves in this zone due to the interference of stress waves, thereby improving rock crushing and reducing the percentage of substandard pieces of rock mass. To ensure the proposed deceleration interval, it is necessary to use the electronic initiation system I-kon III, which provides a minimum step of the deceleration interval of 0.1 ms.

Dolzhikov V. V., Ryadinsky D. E., Yakovlev A. A. Influence of deceleration intervals on the amplitudes of stress waves during the explosion of a system of borehole charges. MIAB. Mining Inf. Anal. Bull. 2022;(6−2):18—32. [In Russ]. DOI: 10.25018/0236_1493_2022_62_0_18.

Dolzhikov V. V., Cand. Sci. (Eng.), Associate Professor at the Department of Explosives, http://orcid.org/0000-0001-8851-2913, Saint Petersburg Mining University, 199106, St. Petersburg, 21st Line, 2, Russia, e-mail: Dolzhikov_VV@pers.spmi.ru;
Ryadinsky D. E., 6th year student of the specialization “Explosives”, Saint Petersburg Mining University, 199106, St. Petersburg, 21st Line, 2, Russia, e-mail: riadinskii.d@mail.ru;
Yakovlev A. A., 6th year student of the specialization “Explosives”, Saint Petersburg Mining University, 199106, St. Petersburg, 21st Line, 2, Russia, e-mail: aleksej.yakovlev.98@mail.ru.

Vadim V. Dolzhikov, e-mail: Dolzhikov_VV@pers.spmi.ru.

1. Simonov P. S. Peculiarities of determining the size of an average piece and the output of oversized pieces during blasting in open pits. MIAB. Mining Inf. Anal. Bull. 2017, no. 4, pp. 320–327. [In Russ].

2. Jia B., Ling T., Hou S., Liu D. Application of Variational Mode Decomposition Based Delay Time Identification in Short Millisecond Blasting. Transaction of Beijing Institute of Technology. 2021, vol. 41 (4), pp. 341–348. DOI: 10.15918/j.tbit1001–0645.2019.308.

3. Yi C., Sjöberg J., Johansson D. Numerical modeling for blast-induced fragmentation in sublevel caving mines. Tunneling and Underground Space Technology. 2017, vol. 68, pp. 167–173. DOI: 10.1016/j.tust.2017.05.030.

4. Gou Y., Shi X., Qiu X., Huo X., Yu Z. Assessment of induced vibrations derived from the wave superposition in time-delay blasts. International Journal of Rock Mechanics and Mining Sciences. 2021, vol. 144, 104814. DOI: 10.1016/j.ijrmms.2021.104814.

5. Yi C., Johansson D., Greberg J. Effects of in-situ stresses on the fracturing of rock by blasting. Computers and Geotechnics. 2018, vol. 104, pp. 321–330. DOI: 10.1016/j. compgeo.2017.12.004.

6. Yastrebova K. N., Moldovan D. V., Chernobay V. I. Solving the issue of ventilating atmosphere of opencast mining by resloping bench face. International Journal of Advanced Science and Technology. 2020, vol. 29 (1), pp. 1–6.

7. Silva J., Li L., Gernand J. M. Reliability analysis for mine blast performance based on delay type and firing time. International Journal of Mining Science and Technology. 2018, vol. 28 (2), pp. 195–204. DOI: 10.1016/j.ijmst.2017.07.004.

8. Karakus M., Ebong U., Liu C., Zhou H. Three-dimensional finite element analysis for rock fatigue damage under dynamic loading. ISRM Regional Symposium, EUROCK 2015, pp. 577–582.

9. Marinin M., Marinina O., Wolniak R. Assessing of losses and dilution impact on the cost chain: Case study of gold ore deposits. Sustainability (Switzerland). 2021, vol.13 (7), 3830. DOI: 10.3390/su13073830.

10. Paramonov G. P., Kovalevskyi V. N., Mysin A. V. Determination of the conditions of an effective functioning of elongated cumulative charges in processing the marble stone. Key Engineering Materials. 2020, vol. 836, pp. 19–24. DOI: 10.4028/www.scientific.net/ KEM.836.19.

11. Blair D. P. Limitations of electronic delays for the control of blast vibration and fragmentation. Rock Fragmentation by Blasting. Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST. 2010, vol. 9, pp. 171–184.

12. Wu H., Gong M. Calculation and application of hole by hole blasting vibration superposition based on measured delay times of detonators. Explosion and Shock Waves. 2019, vol. 39 (2), 025202. DOI: 10.11883/bzycj-2017–0415.

13. Roy M. P., Mishra A. K., Agrawal H., Singh P. K. Blast vibration dependence on total explosives weight in open-pit blasting. Arabian Journal of Geosciences. 2020, vol. 13, no. 13, 531, pp. 1–8.

14. Khokhlov S. V., Rakhmanov R. A., Alenichev I. A., Bazhenova A. V., Makkoev V. A. Study of the issue of management and control of the displacement of the contours of ore bodies after the explosion. Vzryvnoe delo. 2021, no. 132/89, pp. 59–75. [In Russ].

15. Wang Z., Fang C., Chen Y., Cheng W. A. Comparative study of delay time identification by vibration energy analysis in millisecond blasting. International Journal of Rock Mechanics and Mining Sciences. 2013, vol. 60, pp. 389–400. DOI: 10.1016/j.ijrmms.2012.12.032.

16. Fu H., Wong L. N. Y., Zhao Y., Shen Z., Zhang C., Li Y. Comparison of excavation damage zones resulting from blasting with nonel detonators and blasting with electronic detonators. Rock Mechanics and Rock Engineering. 2014, vol. 47 (2), pp. 809–816. DOI: 10.1007/s00603–013–0419–2.

17. Kovalevskiy V. N., Argimbaev K. R. Experimental research of explosive jet penetration in rocks. Gornyi Zhurnal. 2016, no. 12, pp. 19–23. [In Russ]. DOI: 10.17580/gzh.2016.12.04.

18. Paramonov G. P., Kovalevskiy V. N., Mysin A. V. Impact of multicharge detonation on explosion pulse value. IOP Conference Series: Earth and Environmental Science. 2018, vol. 194 (8), 082031. [In Russ]. DOI: 10.1088/1755–1315/194/8/082031.

19. Yastrebova K., Moldovan D., Chernobay V. Influence of the nature of the outflow of explosion products from blast holes and boreholes on the efficiency of rock destruction. E3S Web of Conferences. 2020, vol. 174, 01017. DOI: 10.1051/e3sconf/202017401017.

20. Wang Z., Fang C., Chen Y., Cheng W. A comparative study of delay time identification by vibration energy analysis in millisecond blasting. International Journal of Rock Mechanics and Mining Sciences. 2013, vol. 60, pp. 389–400. DOI: 10.1016/j.ijrmms.2012.12.032.

21. Shi X. Z., Chen S. H. R. Delay time optimization in blasting operations for mitigating the vibration-effects on final pit walls’ stability. Soil Dynamics and Earthquake Engineering. 2011, vol. 31 (8), pp. 1154–1158.DOI: 10.1016/j.soildyn.2011.04.004.

22. Zhang S., Ling T.-H., Liu H.-R., Cao F. Pattern adapted wavelet time-energy density method and its application in millisecond blast vibration signal analysis. Journal of the China Coal Society. 2014, vol. 39 (10), pp. 2007–2013. DOI: 10.13225/j.cnki.jccs.2014.0325.

23. Zhang Y., Chen Y., Chen S., Liu H., Fu Z. Experimental study on deformation of a sandy field liquefied by blasting. Soil Dynamics and Earthquake Engineering. 2019, vol. 116, pp. 60–68. DOI: 10.1016/j.soildyn.2018.09.042.

24. Khokhlov S. V., Sokolov S. T., Vinogradov Y. I., Frenkel I. B. Conducting industrial explosions near gas pipelines. Journal of Mining Institute. 2021, vol. 247, pp. 48–56. DOI:10.31897/PMI.2021.1.6.

25. Qiu X., Shi X., Gou Y., Zhou J., Chen H., Huo X. Short-delay blasting with single free surface: Results of experimental tests. Tunnelling and Underground Space Technology. 2018, vol. 74, pp. 119–130. DOI:10.1016/j.tust.2018.01.014.

26. Huang D., Qiu X., Shi X., Gou Y., Zhou J. Experimental and Numerical Investigation of Blast-Induced Vibration for Short-Delay Cut Blasting in Underground Mining // Shock and Vibration. 2019, vol. 2019, 5843516. DOI: 10.1155/2019/5843516.

27. Kamyansky V. N. Increasing the efficiency of borehole breaking in open pits with multitemporal blasting of borehole charges: Abstract of … dis. cand. tech. Sciences. Moscow, GoI KNTS RAN, 2019, 24 p.

28. Wu X., Gong M., Wu H., Liu X. Parameter calculation of the initiating circuit with mixed use of nonel detonators and electronic detonators in tunnel controlled-blasting. Tunnelling and Underground Space Technology. 2021, vol. 113, 103975. DOI: 10.1016/j. tust.2021.103975.

29. Isheyskiy V., Sanchidrián J. A. Prospects of applying MWD technology for quality management of drilling and blasting operations at mining enterprises. Minerals, 2020, vol. 10 (10), 925, pp. 1–17. DOI: 10.3390/min10100925.

30. Marinin M. A., Khokhlov S. V., Isheisky V. A. Simulation of the process of explosion welding of flat sheet parts. Journal of Mining Institute. 2019, vol. 237, pp. 275–280. DOI: 10.31897/PMI.2019.3.275.

31. Afanasev P. I., Makhmudov K. F. Assessment of the parameters of a shock wave on the wall of an explosion cavity with the refraction of a detonation wave of emulsion explosives. Applied Sciences (Switzerland). 2021, vol. 11 (9), 3976. DOI: 10.3390/app11093976.

32. Alenichev I. A. Reaction of a rock mass in a quarry space to dynamic impacts in the production of blasting. MIAB. Mining Information and Analytical Bulletin. 2018, no. 7. pp. 189–195. DOI: 10.25018 / 0236–1493–2018–7–0–189–195.

33. Cardu M., Giraudi A., Oreste P. A review of the benefits of electronic detonators. Revista Escola de Minas. 2013, vol. 66 (3), pp. 375–382. DOI: 10.1590/S0370–44672013000300016.

34. Andreev R. E., Gridina E. B. A study of gas-dynamic processes in a charge chamber during the explosion of blasthole charges of various designs. Research Journal of Pharmaceutical, Biological and Chemical Sciences. 2016, vol. 7 (3), pp. 2383–2392.

35. Tyupin V. N., Rubashkina T. I. Engineering formulas for determining the size of deformation and damage zones in a fractured rock mass under the influence of blasting in open pits in Transbaikalia. Mining Journal. 2021, no. 7, pp. 40–44. DOI: 10.17580/gzh.2021.07.06.