Method for over-pit and under-pit cooperative control of roofs of far and near fields of an extra-large stoping space

Abstract

The invention relates to a control method for a hard roof of a coal mine, specifically to a method for over-pit and under-pit cooperative control of roofs of far and near fields of an extra-large stoping space. The method provided by the invention overcomes the problem of lack of comprehensive and cooperative control methods for hard roofs of far and near fields of an extra-large stoping space in the prior art. According to a technical scheme in the invention, the method comprises an over-pit vertical hole hydraulic fracturing method, an over-pit L-shaped hole hydraulic fracturing method, an over-pit highly-energy-gathered repetition pulse strong shock wave method, an under-pit water injection method, an under-pit layered blasting method and an under-pit hydraulic fracturing method. The method has the advantages that 1) the problem of great mine pressure of the extra-large stoping space is effectively controlled through over-pit and under-pit cooperative control of the hard roofs of far and near fields; 2) advantages of the variety of methods are given to full play and disadvantages of the variety of methods are mutually compensated, so weakening effect on the hard roofs is substantially improved; and 3) all the over-pit and under-pit holes can be used independently or be used in a shared way, so time, manpower, material resources and money used for hole perforation can be greatly reduced.

Description

TECHNICAL FIELD[0001]The present invention relates to a method for controlling a hard roof of a coal mine, and more particularly, to a method for over-pit and under-pit cooperative control of roofs of far and near fields of an extra-large stoping space.BACKGROUND[0002]With the rapid development of coal industry, the intensive and high-efficient production mode has gradually become a normality of coal mining in recent years. En particular, the application of advanced mining techniques, such as large mining height and higher fully-mechanized mining, leads to a substantial increase in the working face length, the oblique length, the coal seam thickness and the height of roof collapse layer, as well as an abnormal collapse fracturing ratio, which consequently renders an extra-large stoping space and extraordinarily unusual intense pressure during production. In this circumstance, the intense stoping pressure has greatly surpassed the pressure caused by hard basic roof. The destabilized ...

AI Technical Summary

Benefits of technology

The present invention relates to a method for controlling the hard roof in a mining area. The method involves using over-pit and down-pit control methods to effectively control the hard roof in both near and far fields. The advantages of the method include improved weakening effects, greater cost savings, and better safety measures. The down-pit methods can be used after the hard roof has been preliminary weakened through blasting and water injection, which further enhances the weakening effect. Overall, the method cooperates with the over-pit and down-pit methods, achieving better results and reducing costs.

Problems solved by technology

En particular, the application of advanced mining techniques, such as large mining height and higher fully-mechanized mining, leads to a substantial increase in the working face length, the oblique length, the coal seam thickness and the height of roof collapse layer, as well as an abnormal collapse fracturing ratio, which consequently renders an extra-large stoping space and extraordinarily unusual intense pressure during production.

The destabilized fracture of high hard roof stratum causes more complicated stress field and cover rock spatial structure evolution, large-scale and intensive mining disturbance causes not only the cover rock in caving zone to move tempestuously, but also the spatial equilibrium structure in overlaying goaf to be more destabilized, which consequently causes large-scale abrupt pressure changes in the roof stratum in goaf, even impact ground pressure, coal and gas outburst and other dynamic disasters of coal and gas.

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