A blasting method that can effectively reduce the large block rate of blasting in open-pit mines

Abstract

The invention discloses a blasting method capable of effectively reducing a blasting boulder yield of a surface mine. According to the blasting method, holes are drilled quincuncially in a pre-blasted open-air bench (1) according to designed blast hole net parameters, namely a distance (a) between every two blast holes, and a distance (b) between every two rows of blast holes, so as to form a blast hole net composed of 2-3 rows of blast holes (2); an advanced primer cartridge (3) is arranged in a deepened position of the bottom of each blast hole (2), an in-hole micro-delay initiation technology of first initiation of the advanced primer cartridge (3) and later initiation of a top main charge (6) is adopted, and a micro on-off blasting process is adopted to realize advanced weak crack damage to rock mass at the bottom of the hole; moreover, excessive damage and failure, caused by the blasting effect of the explosive at the top, to the bottom bench rock mass can be effectively avoided, and therefore, the boulder yield of the bottom bench can be controlled; meanwhile, by means of meticulous design, the generation of bedrock can be avoided, the mine exploring cost can be effectively reduced, the production efficiency of an enterprise and the safety of operation can be improved, and favorable economic benefits and social benefits can be created.

Description

technical field [0001] The invention belongs to the technical field of blasting engineering in open-pit mines, and in particular relates to a blasting method for reducing the large block rate of open-pit mining steps. Background technique [0002] At present, step deep hole blasting is the most widely used method to excavate ore rock in open-pit mining projects at home and abroad. The factors affecting the large block rate of bench blasting in open pit mining mainly include the distance of the blasting hole of the bench in open pit mining, the parameters of blasting, the method of blasting, the way of charging, and the distance of filling. [0003] Deep hole blasting is an important production process in open-pit mines. In the composition of ore costs, blasting costs account for about 15% to 20% of mine production costs. The quality of blasting directly affects the efficiency of mining, shovel loading and transportation operations. If the blasting large block rate is too h...

AI Technical Summary

Problems solved by technology

However, the above-mentioned methods proposed are either relatively general technical solutions, or the charging procedure is relatively complicated, which is difficult to implement and affects the improvement of production efficiency.

[0007] In addition, for the large pieces after blasting, hydraulic excavators and breakers are usually used for secondary crushing, which not only has low crushing efficiency, but also increases the cost of ore mining, which directly affects the economic benefits and production safety of the mine.

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