Method for processing suspended top by in-hole segmented millisecond blasting

Abstract

The invention discloses a method for processing a suspended top by in-hole segmented millisecond blasting. The method comprises the steps of distance measuring, blast hole forming, primary explosive filling, secondary explosive filling, secondary filling and blasting. Each blast hole sequentially comprises a filling section, an explosive section, a filling section and an explosive section from bottom to top; during blasting, a medium-depth hole in the lower half part is firstly blast and a medium-depth hole in the upper half part is then blast; the medium-depth hole in the lower half part is firstly blast to provide a new downward free surface for the medium-depth hole in the upper half part; after blast, the medium-depth hole in the lower half part forms a small crack in the wall of the medium-depth hole in the upper half part, so that the medium-depth hole in the upper half part blasts gas during blasting to form a gas wedge effect which is combined with stress superposition effect of millisecond blasting to improve utilization of blasting energy, so that effective damages to a suspended top region are formed, and the suspended top collapse probability is increased; while the suspended top is processed, operation times, in the suspended top region, of blasting operators during suspended top treatment can be reduced, and the labor intensity is reduced; and needed explosive amount is smaller in comparison with that of a hole-expanding method.

Description

technical field [0001] The invention belongs to the field of methods for treating suspended roofs of mines, and in particular relates to a method for treating suspended roofs by segmental differential blasting in holes. Background technique [0002] At present, during the blasting of medium and deep holes in underground mines, due to the corresponding upper horizontal abandoned piercing veins, no effective caving is carried out, and the newly withdrawn piercing veins are likely to form a suspended roof phenomenon. At present, the hole expansion method is used to deal with the suspended ceiling. It means that after the overhang occurs, find out the supporting part of the arch foot of the overhang, charge and ream the corresponding part of the overhang foot in the follow-up platoon to form a medicine pot, and then charge the medicine pot, and make the overhang through blasting. The project loses the support of the arch foot, so as to deal with the suspended roof. The advantage...

AI Technical Summary

Problems solved by technology

[0002] At present, during the blasting of medium and deep holes in underground mines, due to the corresponding upper level abandoned piercing veins, no effective caving is carried out, and the newly mined piercing veins are likely to form a suspended roof phenomenon. Currently, the hole expansion method is used to deal with the suspended ceiling. It means that after the overhang occurs, find out the supporting part of the arch foot of the overhang, charge and ream the corresponding part of the overhang foot in the follow-up platoon to form a medicine pot, and then charge the medicine pot, and make the overhang through blasting. The project loses the support of the arch foot, so as to deal with the suspended roof. The advantage of this treatment method is good reliability, but the disadvantage is that the process is cumbersome and takes a long time. The vault loses its support balance, and the vault naturally collapses against the ground pressure. Secondly, the upper vault is destroyed as much as possible, and it is blasted through the upper segmental covering layer, forming the condition for the vault to disintegrate and collapse. Due to the insufficient pressure of the upper horizontal covering layer Moreover, the height of the suspended roof is too low, causing the top of the horizontal stope to collapse against the pressure of the ground pressure; when the hole reaming method is used to deal with the suspended roof, hole reaming is required, resulting in the blasting operators being exposed to the suspended roof area for many operations and high labor intensity. Due to the need to charge the medicine pot with the hole-enlarging method, the amount of explosive required is large.

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