METHOD FOR PREPARATION OF EXTRACTION PILLAR Russian patent published in 1995 - IPC

FIELD: mining. SUBSTANCE: method for preparation of extraction pillar in mining of mineral gently dipping seams with stable inundated rocks of upper roof includes driving of main and excavation workings and mounting room, and joining of excavation workings by connections; dewatering of inundated rocks occurring in seam roof by hole drilling; installation of filters and longwall mining of part of extraction pillar up to upper roof caving. Drainage working is driven on the side opposite to direction of advance of mining of extraction pillar adjacent to mounting room. Draining hollow is formed adjacent to mounting room or leaving pillar of mineral between them in roof parallel to longwall front by preliminary partial mining of extraction pillar from mounting room up to sagging of rocks overlying the seam and separation of upper roof from rocks. Inclined upward holes are drilled from drainage working towards longwall advance to draining hollow, water head is relieved, and mining of extraction pillar is continued. Holes from drainage working are drilled at angle of roof rock caving. Additionally drilled to the middle of draining hollow from the surface are unwatering holes. EFFECT: higher efficiency. 3 cl