The reasonable width of coal pillars in the short-wall continuous mining with full roof falling

In view of the short-wall continuous mining in bound coal recovery, in order to solve the problem of key strata large-area instability caused by chain damage of remaining pillar, based on the analysis of two fracture movement forms of key strata, and with the control of large-area fracture movement of key strata as the principle, the "bound coal recovery technology of short-wall continuous mining with full roof falling " was put forward: barrier pillar are to be set between the first and second block section to keep the pillar stable during the mining of the first block section; the full fracture movement of the key strata caused by the coal pillar damage and instability during the mining of the second block section helps realize the coordination and coupling between the damage of pillar and the fracture movement of the key strata; the complete cancelation of barrier coal pillars in the subsequent blocks section realizes the continuity of the roof movement and settlement. The length of first block section should be less than the initial fracture step in the key strata to prevent the critical and unstable state of the plastic hinged lines of key strata. From the perspective of elastic and plastic partition of isolated coal pillar, the width of plastic partition and the critical width of middle elastic area of the coal pillar to keep stable were analysed, and the width criterion of isolated coal pillar was establish. © 2017, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.