Method for pillar recovery in chamber-and-pillar working and tubbing unit for pillar recovery

Methods for pillar recovery in chamber-and-pillar working materials in underground stratified beds are disclosed. Additionally, tubbing units for pillar recovery in chamber-and-pillar working of materials in underground stratified beds are disclosed. An extraction device is aligned obliquely to pillar galleries located between the pillars and the roof is supported in front of the retreat face of the extraction device with a plurality of tubbing units, each tubbing unit being adjustable in height and width and movable through operation of a vehicle. The tubbing units may be moved through other tubbing units that are set, and reset in another position.