Pressure-relief gas drainage top caving coal mining method for extremely thick hard coal seam

Abstract

The invention discloses a pressure-relief gas drainage top caving coal mining method for an extremely thick hard coal seam and belongs to the technical field of top caving coal mining. The pressure-relief gas drainage top caving coal mining method is characterized in that a top caving coal working face is arranged along the bottom of the extremely thick hard coal seam; a lower connected roadway and an upper connected roadway are respectively and obliquely arranged on a top caving coal working face transportation roadway and a top caving coal working face air return roadway and reach the top ofthe extremely thick hard coal seam; one group of high-level technical roadways arranged in parallel is driven along the top of the extremely thick hard coal seam at intervals; the high-level technical roadways are communicated by using one group of connection roadways arranged at intervals; adjusting air windows are arranged in the connection roadways and are used for controlling ventilation; high-level gas drainage pipes are arranged in the high-level technical roadways; drilling fields are arranged in the connection roadways; drill holes are downward applied by using the drilling fields; liquid carbon dioxide blasting generators are arranged in the drilling holes and are arranged ahead of the top caving coal working face. According to the pressure-relief gas drainage top caving coal mining method disclosed by the invention, safety mining of the working face is realized and the working efficiency is high; by adopting liquid carbon dioxide, the blasting essence is safe and migration and drainage of gas to the high-level technical roadways are facilitated.

Description

Technical field: [0001] The invention relates to the technical field of top-coal caving mining, in particular to a method for pressure relief and drainage of gas in a huge thick hard coal seam. Background technique: [0002] The geological conditions of my country's coal seams are complex. As a high-yield and efficient mining technology, top-coal caving mining has been popularized and applied to a certain extent. However, the low coal recovery rate of the top-coal caving mining method and the difficulty of gas control in the working face are the constraints that affect its development. Especially when the top coal caving is mined under the condition of extremely thick and hard coal seam, the problem is particularly prominent. [0003] At present, the technical methods of coal seam enhancement and pressure relief proposed by domestic scholars mainly include explosive deep hole pre-splitting blasting, hydraulic fracturing, hydraulic punching, hydraulic cutting, hydraulic slotti...

AI Technical Summary

Problems solved by technology

Due to the defects of some anti-reflection technologies and process methods, the effect of many technical measures is not ideal

[0004] Patent document CN201610263144.5 discloses a method for caving top-coal in weakened hard coal seams based on carbon dioxide blasting, which uses carbon dioxide blasting to weaken the hard top-coal, so that the top-coal release rate is increased by 20% to 30% compared with that before roof fracturing , but the drilling at the roof between the two hydraulic support beams near the coal wall has a greater impact on the production of the working face

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