A Roof Controlled Blasting Method for Ore Body Recovery with Soft Broken Roof

Abstract

The invention discloses a roof-control blasting method for soft and fractured roof ore body recovery. A control blasting technology is adopted to break ores under a blasting layer through millisecond blasting; and an ore roof supporting layer is reserved, so that safety of a stope roof is maintained. The method adopts a short-hole drilling mode to form control blast holes and main blast holes, the control blast holes are formed in a control blast line, and the main blast holes are vertically arranged perpendicular to a rock drilling working surface; and millisecond detonators are adopted, the main blast holes are blast row by row along a free surface, and the control blast holes are finally blast once to downwards press ores. The roof-control blasting method is suitable for ore body recovery which has an obvious ore body boundary, an unstable roof, firm and stable ores, and needs keeping ores to support the roof, effectively keeps ores to support the roof, and prevents stope ore loss caused by roof collapse, so that a recovery ratio is increased; and meanwhile, roof waste rocks are effectively prevented from mixing, so that an ore dilution rate is reduced.

Description

technical field [0001] The invention relates to an underground mine mining method, in particular to a roof controlled blasting method for recovering an ore body with a soft broken roof. Background technique [0002] In recent years, with the increasing social demand for bauxite mineral resources and the depletion of easily exploitable surface resources, my country has shifted from open-pit mining to underground mining. According to the occurrence conditions of bauxite ore, bauxite ore is hard and stable, but its immediate roof layer is thin, with well-developed lamina, soft and brittle, and its compressive strength is extremely low. During the production process, the roof will collapse when it is exposed, seriously affecting Stope safety. The comprehensive mining method currently adopted in the underground of bauxite mines in China has a very large amount of ore loss due to the failure of the working face due to the collapse of the roof. Ordinary shallow hole ore blasting ...

AI Technical Summary

Problems solved by technology

According to the occurrence conditions of bauxite ore, bauxite ore is hard and stable, but its immediate roof layer is thin, with well-developed lamina, soft and brittle, and its compressive strength is extremely low. During the production process, the roof will collapse when it is exposed, seriously affecting Stope safety

The comprehensive mining method currently adopted in the underground of bauxite mines in China has a very large amount of ore loss due to the failure of the working face due to the collapse of the roof. Ordinary shallow hole ore blasting method is either over-excavation or under-excavation, and it is difficult to reserve a regular thin ore top protection layer. Even if the top protection layer is barely left, it often fails to meet the strength requirements of the support roof due to blasting.

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