Rock Pre-Fracturing Effect on Performance of Blast Crushing
Feasibility of the studies aimed at development of new rock pre-fracturing processes, applicable in the drilling and blasting mining technology is discussed. With increase in mining depth the previously beneficial effect of higher power consumption for primary crushing, followed by substantially reduced power costs of the secondary ore crushing at orepreparation plants, leads to sharp increase in present-day costs of the primary drilling and blasting operations. The conventional rock prefracturing processes, based on the preliminary weakening of rock strength by surfactants, electrophysical and other effects are not popular in the commercial rock-fracturing processes, because most of them are not commercialized and appreciably increase the total mining costs. The short-delay blasting process under consideration provides the mechanism for lower power-consumption in the dynamic rock fracturing due to formation of critical tension stress zones at some areas, thus inducing the conditions for rock pre-fracturing. Moreover, the rock fracturing process can be controlled within the range from a single-focal fracturing in a quasi-static load zone to a multifocal fracturing under a pulse tension effect The tests on physical models and the mathematical modeling make the ground to establish the efficiency of the sinusoid-type short-delay blasting process with lower specific explosive consumption. Analysis of the granulometric composition of the blasted mass in the study models reveals that the sinusoid-type short-delay blasting process, used under conditions of higher initial compressive stresses, improves the crushing performance in the study models as compared to the conventional shortdelay blasting processes with the rectilinear explosive charge arrangement The necessity of the differential approach to the optimal delay parameters setting with consideration for a stress-strain state of a rock mass to be blasted is substantiated. The crushing effect of the explosive charge blasting is achieved by the shorter-delay blasting of explosive charges in a zone of pre-fractured rocks.
G.N.Volchenko V.M.Seryakov V.N.Fryanov
Siberian State Industrial University,Russia Institute of Mining, Siberian Branch, Russian Academy of Sciences, Russia Siberian State Industrial University, Russia
国际会议
厦门
英文
241-246
2011-08-10（万方平台首次上网日期，不代表论文的发表时间）