Method for breaking roof at fixed point in connection roadway of double retracement channel

Abstract

The invention belongs to the technical field of mine pressure control at the end mining stage of a long-wall working face, and in particular relates to a method for breaking a roof at a fixed point ina connection roadway of a double retracement channel. The method comprises the following steps that step 1, an arrangement mode of a pre-dug double retracement channel is designed, the pre-dug doubleretracement channel comprises a main retracement channel and an auxiliary retracement channel which are arranged side by side, wherein a return air gateway and a main transportation gateway are connected to the two ends of the main retracement channel and the auxiliary retracement channel correspondingly, and the main retracement channel and the auxiliary retracement channel are connected throughthe connecting roadway; step 2, when the working face is advanced to a distance of 50-100 m to the main retracement channel, a fan-shaped blasting hole is drilled to the roof in the middle of the connecting roadway of the main retracement channel and the auxiliary retracement channel; and step3, a dual-energy-gathered blasting device is installed in the blasting hole, then explosive is charged, and when the working face is advanced in a distance of above 30-50 m, a blasting pre-splitting work is completed in advance to realize that the basic roof breaks along the section where the fan-shapedblasting hole is located when the working face approaches the main retracement channel. The large predicted deviation of roof breakage position caused by inaccurate measurement of upcoming load distance is avoided.

Description

technical field [0001] The invention belongs to the technical field of mine pressure control at the final mining stage of a longwall working face, and in particular relates to a method for breaking a roof at a fixed point in a connecting roadway of a double withdrawal channel. Background technique [0002] The relocation and reverse work of the fully mechanized mining face is a crucial link in the preparation of mine production. During the final mining period, the control of the working face and the roof of the withdrawal channel and the moving speed directly restrict the improvement of the unit yield level and the safety quality of the fully mechanized mining face. guarantee. [0003] The existing retraction technologies for fully mechanized mining face mainly include three types: no pre-excavation retraction channel, pre-excavation double retraction channel and pre-excavation single retraction channel. [0004] Pre-excavation of double retraction passage means that two au...

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Problems solved by technology

[0009] However, the on-site determination of the pressure relief position of the production stoppage is only based on the empirical value of 5-6 m, which sometimes leads to no pressure after the production stoppage exceeds 24 hours, and sometimes the support is compressed during the retraction process due to improper application of the pressure relief measures. Such as the 31401 working face of Ulan Mulun Mine and the 22103 working face of Daliuta Mine in Shendong Mining Area

[0010] It can be seen that in the final mining stage of the working face, due to many factors that affect the size of the step distance in the cycle, when the mine pressure observation cannot accurately locate the step distance, blindly adopt the method of adjusting the mining height or mining speed. On the contrary, the pressure control method may lead to unfavorable roof failure forms after the working face and the withdrawal channel are connected.

Therefore, the application of yielding mining technology is conditional. It is not enough to determine the yielding position and adopt yielding mining measures based on experience alone, and it is difficult to guarantee the accuracy and reliability of pressure relief. It is necessary to adopt compulsory methods to achieve the basic top. fixed point break

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