Research and Application of Open‐Off Cut Roof Cutting Pressure Releasing Technology

Abstract

The first weighting control is one of the difficult problems that cannot be avoided in the safe and efficient production of longwall mining face. To optimize the existing pressure releasing technology of open-off cut, the open-off cut roof cutting pressure releasing (OCRCPR) technology is put forward on the basis of roof cutting pressure releasing gob-side entry retaining (RCPRGER) technology. Firstly, the mechanism of the technology and the design method of related key parameters are summarized. Then the pressure releasing effect of OCRCPR and the stress environment change under this technology are analyzed by mechanics calculation and numerical simulation, respectively, which verify the feasibility of the OCRCPR technology from the theoretical level. Finally, a test mining face is taken as an example to implement the field test. The field test results show that the OCRCPR can effectively shorten the first weighting step and weaken the first weighting strength and has a good pressure releasing effect.

Study on the Support System Mechanism of Entry Roof with Roof Cutting Pressure Releasing Gob‐Side Entry Retaining Technology

“…As the problems of fast filling and retained entry stability control are difficult to be solved effectively, compared with the working face mining advance, the construction of the gob-side entry retaining often lags behind. What's more, the traditional entry retaining methods usually have high cost and complex working procedures, which seriously restrict the application and development of this technology [15].…”

Research on process parameter optimization of irregular coal face

“…With the progressive deepening of mining operations, the incidence of regional pressure bumping events has become more frequent, particularly in areas with intricate geological structures 1 , 2 . In view of the prevention of such mine disasters, different experts and scholars have given different solutions, among which roof cutting and pressure releasing is a common way 3 – 6 . In the transverse direction, the roof cutting measures can effectively destroy the integrity of the rock strata, cut off the transmission of force, reduce the range of rock strata moving in the transverse direction at the same time, and achieve the purpose of reducing the intensity of mine pressure.…”

Air Flow Movement Law in Working Face and Gob with Roof-Cutting and Pressure-Releasing Mining: A Numerical Simulation and Engineering Verification

“…Compared with the traditional longwall mining, the stress evolution of the overlying strata in the gob has changed in “roof-cutting and pressure-releasing” mining, which results in the change of the pressure relief, caving and stress field of the gob roof; therefore, the permeability of the mined-out area changes. , In the process of “roof-cutting and pressure-releasing” mining, the roadway is directly adjacent to the gob. Without any blocking measures, the gob is “open” to the roadway, and the gas inside the gob is easy to escape from the gob to the roadway .…”

“…9−11 Nowadays, the global coal resource situation is relatively severe, and "roofcutting and pressure-releasing" without coal pillar mining has become the trend of future coal mine production. 12 Compared with the traditional longwall mining, the stress evolution of the overlying strata in the gob has changed in "roof-cutting and pressure-releasing" mining, 13 which results in the change of the pressure relief, caving and stress field of the gob roof; therefore, the permeability of the mined-out area changes. 14,15 In the process of "roof-cutting and pressurereleasing" mining, the roadway is directly adjacent to the gob.…”