Double-trench flat-bottom mining method for ores difficult to mine

Abstract

The invention provides a double-trench flat-bottom mining method for ores difficult to mine. The method includes the process steps that firstly, based on a sublevel caving method without sill pillars, three inlet channels are classified into one stoping unit, a transverse ore outlet channel is made from the middle inlet channel to the inlet channels on the two sides, and a bottom structure for double-trench ore falling and flat-bottom ore discharging is formed; secondly, in the stoping process, just like the inlet channels conducted through the sublevel caving method without sill pillars, for the trenches in the two sides, row-by-row blast hole blasting is conducted for mining retract, the ores do not stop being discharged until a driver of a scooptram does not enter an open stope and the ores cannot be discharged, and the caved ores which fall into the open stope and the ores which fall after roof hanging are discharged through the transverse ore outlet channel; thirdly, stoping is conducted at the two trenches at the same time, and the continuous mined-out area span is formed and exceeds the critical falling span of the hanging roof ores and roof surrounding rock, so that the roof surrounding rock falls naturally along with falling of the ores, and a covering layer is formed; and fourthly, the ores stop being discharged after the ores discharged from the transverse ore outlet channel reach the cutoff grade, an ore outlet roadway is formed through row-by-row caving in an inlet channel mining retract manner according to the sublevel caving method without sill pillars, and ridge residual bodies are recovered.

Description

technical field [0001] The invention relates to an iron ore mining method, in particular to a double-cut ditch and flat-bottom mining method for a difficult-to-mine ore body. Background technique [0002] At present, iron ore mines across the country, especially some old mines in the 1980s and 1990s, are generally severely damaged by small mines and become incomplete ore bodies. At present, the segmental caving method without bottom pillars is used for mining. Due to the incomplete and damaged ore body, the cutting engineering and ore falling blast holes cannot be fully in place during the mining process, resulting in poor blasting quality, which makes the ore on the more stable roof and the ore on the residual pillar often collapse. Do not come down, resulting in suspended ceiling and partition wall. In addition, in the stopes of some primary ore bodies with small thickness, the surrounding rocks of the roof often cannot be removed at any time, causing the ore to collapse ...

AI Technical Summary

Problems solved by technology

At present, the segmental caving method without bottom pillars is used for mining. Due to the incomplete and damaged ore body, the cutting engineering and ore falling blast holes cannot be fully in place during the mining process, resulting in poor blasting quality, which makes the ore on the more stable roof and the ore on the residual pillar often collapse. not come down, resulting in suspended ceiling and partition wall

In addition, in some primary ore body stopes with small thickness, the surrounding rocks of the roof often cannot be removed at any time, causing the ore to collapse into the empty pit and cannot be released.

Under these circumstances, the stope structure of the end-exit mine of the pillarless segmented caving method is very unsuitable. Not only the ore falling into the open field cannot be released, but also the roadway arranged in the skarn layer is difficult to maintain, resulting in Poor production reliability and large ore loss