Ultra-deep hole pre-splitting blasting method

Abstract

The invention discloses a method for presplitting blasting for ultra-deep holes. Presplitting blast holes (7), guide blast holes (8) and presplitting blast holes (7) are cyclically formed at intervals, a strengthening charging section h1, a normal charging section h2, a weakening charging section h3 and a filling section h4 are formed in each presplitting blast hole (7) separately from bottom to top, and a strengthening presplitting grain (5'), a normal presplitting grain (5) and a weakening presplitting grain (5") are bound on a secondary detonating cord (1) separately, and installed in each presplitting blast hole (7); a bottom strengthening grain (6) is continuously bound on an auxiliary detonating cord (1'), and installed at a bottom of each guide blast hole (8); and each secondary detonating cord (1) and the corresponding auxiliary detonating cord (1') are lapped with a primary detonating cord outside the corresponding hole, a non-electric millisecond delayed blast nonel detonator is used for blasting, the presplitting blast holes (7) and the guide blast holes (8) are blasted simultaneously, and at least 150ms ahead of blasting for primary blast holes. According to the method disclosed by the invention, a presplitting guide function of the guide blast holes (8) is adequately utilized, a presplitting line is formed well, a hanging-wall phenomenon of a rock body is effectively avoided, an overbreak amount is reduced, and safety and stability of a side slope are controlled.

Description

technical field [0001] The invention belongs to the technical field of pre-splitting blasting of slopes in open pits, and in particular relates to a super-deep hole pre-splitting blasting method, which is particularly suitable for ultra-deep hole pre-splitting blasting by side and section steps. Background technique [0002] Open-pit mining destroys the original stratum structure, reduces the stability of the ore rock, and may cause the slope of the stope to be unstable. In order to reduce the damage and over-excavation phenomenon of the final slope rock mass caused by blasting adjacent to the sidewall, and ensure the stability of the final slope within the service life of the mine, the pre-splitting blasting method is generally used to deal with the side slope. In conventional blasting, when encountering soft rock formations, guiding pre-splitting blast holes is a common method of pre-split blasting. Protect the surrounding rock, reduce over-excavation, form a good section...

AI Technical Summary

Problems solved by technology

However, the blasthole depth of this method is only 14.1-14.6m, which is not suitable for ultra-deep hole pre-splitting blasting with a drilling depth of 20m-30m and parallel steps.

Images