Within the scope of this study, forwarded to analyse the whole underground stability of the open stopes and pillars in the longhole stoping with post backfill method which is applied at Asikoy underground mine, a series of rock mechanics tests were carried out on the core samples taken from the ore (chalcopyrite), surrounding rock (basalt) and backfill material and the geomechanical properties of the samples were determined. In order to calculate the stress and deformation around underground openings, Phase(2) which is a two-dimensional elastoplastic finite elements program was used and the stability analysis was performed separately for the open stopes and pillars
