Pacific National University, Khabarovsk, Russia:

E. B. Shevkun, Professor, Doctor of Engineering Sciences
A. V. Leshchinskiy, Professor, Doctor of Engineering Sciences

JSC “Uralugol”, Chegdomyn, Khabarovsk, Russia:
A. A. Galimyanov, Head of Blasting Area

The article reports theoretical and experimental data on productive blasting in open pit mines and in special earthwork aimed to improve blast control and fragmentation of hard rocks by drillingand-blasting using charges with air-filled cavities at the ends. From experimental blasting, the air cavities at the ends of explosive charges in combination with the scheme of directional short-delay blasting ensure more uniform energy distribution along the height of blasted rock mass (bench), reduce average size and yield of oversize, enable smaller disintegration of broken rock, eliminate depth-ward ejection of rock and limit hazardous flying of rock. Efficiency of the proposed technology ensues from reduction in overdrill, charge height and in powder factor and from enhanced production output of extraction-and-loading. The explosive charges and technologies of energy-saving fragmentation of hard rocks by blasting, developed, patented and approved on a commercial level, are recommended for common application in open pit mines in Russia.

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