STABILITY ANALYSES OF UNDERGROUND ROOM AND PILLAR STOPES BY MEANS OF CONVERGENCE

This paper deals with the convergence data obtained from the room and pillar stopes of Panasqueira mine. Convergence velocity is the parameter that has been used in the mine to detect the proximity of failure. However, the value of the cumulative convergence is another useful parameter with which the roof to floor convergence near the pillars of 11m by 11m and 3m by 3m sections can be easily recognised. It is also found that the failure criterion based on the convergence velocity that was used in the past is insufficient and a new criterion combining both the cumulative convergence and its velocity is a better option. The suggested critical values of the new criterion are given by the authors