ABSTRACT
Within boundaries of central ore field of Zhezkazgan copper 82% of all reserves are concentrated at overlapping ledges with different extent of overlap and with thickness of interlayers from 0.5 up to 10 or more metres. Mining of ledges is carrying out mainly by chamber-and-pillar system with open face. When complete overlapping after chamber reserves extraction intricate geomechanical construction is formed which may be pliant or stiff in different mining-and-geological conditions. In accordance with this loads are formed on interchamber and barrier pillars. As a result of investigations of loads distribution on pillars when extracting of chamber reserves at 3 overlapping ledges behaviours are established of loads forming on pillars and their numerical values for different depths, different compositions of rocks and interlayers thickness, also established for which it is possible pillars location independently from each other at every of layers overlapping ledges.
