WAYS TO REDUCE MIXING OF ORE BODIES WITH WASTE ROCKS DURING EXPLOSIVE MINING IN COMPLEX QUARRIES

Abstract

Ore pits with a complex structural structure are characterized by heterogeneity of the massif (ore-waste rock) represented by different acoustic rigidity and strength. During explosive mining in such arrays, they are mixed at the ore and empty rock contact line, and the extracted ore is diluted with empty rocks.

During the explosive development of complex-structured deposits by the open method, reducing the mutual mixing of ore and host rocks is one of the key tasks of increasing the technological efficiency of mining operations. Reducing the mixing of ore bodies with empty rocks is possible only with a decrease in the width of the collapse of the exploded mass, taking into account the nature of the distribution of the rock from the massif to the collapse.

It is proved that the efficiency of mining complex-structured ore pits is associated with the problem of obtaining ore and non-metallic debris. It has been established that when exploding complex faces, it is very important to increase the duration of the stress wave and reduce the peak pressure of the gaseous products of the explosion, thereby increasing the destructive effect of the explosion.

A new blasting technology is proposed: by determining the optimal parameters of the borehole grid, the size and design of the charge, taking into account the strength and acoustic rigidity of ore and non-metallic rocks, allowing reducing the limiting pressure of gaseous explosion products and increasing the duration of its impact on the exploding medium, as well as creating a cutting gap (creating an artificial air barrier) along the contour of conditioned ores, this leads to a decrease in the energy of the explosion at the interface between conditioned and substandard (off-balance sheet) ores. This helps to reduce the degree of their mixing and obtain the ruins of conditioned and substandard ores of various shapes and sizes.