Effect of deceleration intervals on the mechanism of explosive loosening of rocks

The issues of the influence of deceleration intervals between successive explosions of borehole charges on the quality of explosive loosening of rocks by explosion, taking into account the two-stage mechanism of rock destruction under the action of explosive loads, in order to select the optimal values of deceleration based on the latest scientific achievements in the of crack growth in the zone of destruction of each charge. The analysis of the development of an experimental mass explosion with unsatisfactory results is carried out. An ordinal explosion initiated by a waveguide system with a deceleration between the rows of charges by a surface detonator with a nominal value of 150 ms, and along the row a deceleration of 8 ms is formed due to the activation of a waveguide with a deceleration of 2 ms/m. Graphical modeling of the development of an experimental mass explosion, in comparison with the commonly used 400x200 ms scheme, proved that the charge destruction zones along the row develop no more than 3 ms — before the arrival of a voltage wave from the explosion of the previous charge, which stops the formation of the destruction zone. With the 400x200 ms blasting scheme, destruction zones are formed to theoretically possible sizes, which allows the screening effect of a previously destroyed rock mass to be used for crushing, allowing part of the energy of the stress wave to be reflected into the charge destruction zone and the rest of the energy to be refracted into the previously exploded rock mass. Almost all the energy of the charge explosion is spent on crushing — there is no collapse of the rock mass outside the block.

Keywords: explosive loosening of rocks, contacts of ores and rocks, displacement of rocks during an explosion.
For citation:

Shevkun E. B., Plotnikov A. Yu. Effect of deceleration intervals on the mechanism of explosive loosening of rocks. MIAB. Mining Inf. Anal. Bull. 2023;(12-1):159—169. [In Russ]. DOI: 10.25018/0236_1493_2023_122_0_159.

Acknowledgements:
Issue number: 12
Year: 2023
Page number: 159-169
ISBN: 0236-1493
UDK: 622.235
DOI: 10.25018/0236_1493_2023_122_0_159
Article receipt date: 05.10.2023
Date of review receipt: 27.10.2023
Date of the editorial board′s decision on the article′s publishing: 10.11.2023
About authors:

Shevkun E. B., Dr. Sci. (Eng.), Professor, Pasific Nacional Universiti, e-mail: ev.shevkun@ yandex.ru, orcid: 0000−0001−9002−4943;
Plotnikov A. Yu. Cand. Sci (Eng), “AVT-Amur”, Blagoveshchensk, 17, Amur St., e-mail: plotnikov1960@hotmail.com.

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