Analysis of the stress strain formation in a rock mass in mining the split layer

Geomechanical situation is analyzed in mining the ore body of kimberlite pipe “International” during underground working of the experimental-industrial block. Split layer winning was accomplished using the room-and-pillar system with ore-breaking by continuous miner and solid stowing. When conducting second working, instrumental and visual observations were completed for the state of pillars and stopes. Results of observations are used to analyze changes in the stress strain state for secondary working development in the split layer. Analysis was made on the basis of numerical calculations of the stress state of the constructive elements (elements are performed by method of boundary singular equations). In-situ data allowed to estimate stress values in pillars and roof of stopes and to apply them as criteria in further analysis of block development conditions. Optimal parameters are obtained for the development system and conditions of accomplishing mining works in the undercutting layer. Regularities are established for the stress state formation in sublevel cutting under conditions of additional development. This made it possible to determine optimal order of stope winning in the layer.