Stability analysis of security pillars with dimension 10 x 10 m fromed by ore of mineral body during the exploitation of the "Trepça" mine in Stantërg

The "Trepça" mine in Stanterg consists from several mineral bodies, which if compared to the mineral bodies in the North and South part of mine can be found in different size. Their size in the horizontal plane ranges from 300–7000 m² and as a matter of fact in the primary exploitation phase, only about two of thirds part of ore is used, while the remaining ore is used like pillars in the secondary stage with special methods. Since the beginning of exploitation at "Trepça" mine landfill, the security pillars are left in dimensions 10 x 10 m, on the schedule of chess fields, at distances from 16 to 20 m and all pillars at those distances are stable and over-dimensioned. In this paper we investigate the stability of the securing pillars with dimensions 10 x 10 m, with surface S = a * b = 10 * 10 = 100 m² with a distance between them of 10 to 22 m. Pillar stability analysis aims to increase the safety factor along with the increase of exploitation depth.