STATE ANALYSIS OF OVERWORKED AND UNDERWORKED PARTING BETWEEN CONTIGUOUS SEAMS AND DURING THEIR SIMULTANEOUS TOP-DOWN MINING

Purpose. Investigating conditions of conducting and maintaining excavation works during mining of seam C-8(l). Evaluating probability of parting rocks stability loss in terms of top-down mining of two contiguous seams in a series. Methods. Carrying out computational experiments by finite elements method for investigation of the stress-strain state of lithological varieties of parting which is overworked and underworked by stoping on seams C-9 and C-8(l). Findings. The paper presents the results of the analysis of the vertical and horizontal stress components distribution zones along all the height of the parting for the rock types compiling it, treating separately the impact produced by stoping on seams C-9 and C-8(l) on the formation of the stress-strain state. Originality. The research substantiates the possibility of disturbed rocks sections interlocking and formation of a single zone of softening along the thickness of parting during combined (with a certain displacement in the seam plane) top-down stoping on the series of seams C-9 and C-8(l), which are not referred to as "adjacent seams" according to the normative documents. Practical implications. The paper describes the possibility of the significant interrelation of contiguous seams during their simultaneous top-down stoping even if they are not related to the category of "adjacent seams". Therefore, in severe mining and geological conditions, it is recommended to estimate the probability of rocks softening along all the height of the parting.