Goaf Pillar Method for Subsidence Control

摘要

The paper describes a new method of partial extraction below important surface and underground features viz, the "Goaf Pillar Method". The paper also describes the methodology involved and its application to two case studies (1) Kurja Underground Project of Hasdeo Area, South Eastern Coalfields Limited (SECL), where a large area lies below important surface features and (2) Chinakuri Mine No.Ⅲ of Eastern Coalfield Limited where Borachak seam, lies 160 m below water-logged Bharatchak seam. The "Goaf Pillar Method" is designed in both the cases with an aim to control the subsidence with maximum possible recoveries. Further, in the latter case, the health of the designed pillars left-out in the goaf were remotely monitored using strain bars grouted in the sides of these goaf pillars. The observations indicated no failure of any of the goaf pillars except some side spalling.