GRAIN SIZE COMPOSITION OF BROKEN ROCKS UNDER DIFFERENT CONDITIONS OF BLASTING
The article describes the improved analytical method of determining grain size composition of broken rocks under blasting. The method takes into account dimension of heavy fragmentation zones around blastholes and content of natural joints in rock mass. The radii of heavy fragmentation zones are calculated using the preset physico-mechanical properties of rocks and physicochemical characteristics of explosives. Grain size compositions of natural joints are calculated using the average size of joints in rock mass. The grain size composition of broken rocks is largely influenced by the wave reflected from free surfaces in rocks and by swelling effect of explosion. The swelling effect of blasting is included in the value of the extra fragmentation coefficient. By means of integration of these influencing factors, the analytical method is developed for the first time to determine every size grade in blasted rock. The software program is designed for automatic determination of grain size composition of blasted rocks by associating influences of physico-mechanical properties of rocks, physicochemical characteristics of explosives and blast design parameters. Using this program, grain size compositions of blasted rocks were calculated at different parameters of blast designs applied in open pit mines in Kazakhstan. Comparison of the theoretical and experimental data showed their high-level identity. This result proves that the proposed theoretical approach to determination of grain size composition of broken rocks takes into account actual mechanism of explosive fracture of real rock mass. Scientific literature contains no information on such calculation methods of grain size composition of broken rocks.
For citation: Rakishev B. R., Orynbay A. A., Auezova A. M., Kuttybaev A. E. Grain size composition of broken rocks under different conditions of blasting. MIAB. Mining Inf. Anal. Bull. 2019;(8):83-94. [In Russ]. DOI: 10.25018/0236-1493-2019-08-0-83-94.
: Rakishev B. R., Orynbay A. A., Auezova A. M., Kuttybaev A. E.
B.R. Rakishev, Academician of National Academy of Sciences
of the Republic of Kazakhstan, Doctor of Technical Sciences, Professor,
A.M. Auezova, Candidate of Technical Sciences, Associate Professor,
A.E. Kuttybaev, Candidate of Technical Sciences, Senior Lecturer,
A.A. Orynbay, PhD student , Senior Lecturer,
Satpayev Kazakh National Research Technical University, 050013, Almaty, Kazakhstan.
Corresponding author: B.R. Rakishev, e-mail: firstname.lastname@example.org.Key words
Limit explosion chamber radius, fragmentation zone radius, conditional content of natural joints, heavy fracture volume, automatic determination of grain size composition of broken rocks.References
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