Stability of underground openings is one of the critical challenges in the mining industry. A mine support system design and installation depends on the conditions of mining. This is especially pronounced in the regions of active tectonics with horizontal stresses higher than vertical stresses up to 2–5 times. The tectonic stress-induced activity accompanies even comparatively shallow mining operations. Dense fracturing, spalling and bursting are observed in mines in Gornaya Shoria, or in Apatit JSC mines, at the depths of 150 to 400 m in Russia, at the depth of 260–400 m in uranium mines in Canada, 250 m in Tirol in Austria, or 100–200 m in Norway. As a result of the accomplished studies, the mechanism of fracture zones in adjacent rock mass during heading and mining in high-stress rock mass is defined. The parameters of these zones are determined subject to the rock mass quality, structure and stress–strain behavior. This allows developing the heading technology and mine support system design for the conditions of higher tectonic stresses. The main transient factors capable to affect underground openings are identified, and it is shown that the technology of heading and mine support under dynamic events caused by rock pressure depends on such determinants as: the quality of fragmentation by blasting, blasting sequence, temporary and permanent support designs and lag of the mine support behind the face advance. The proposed approach to the underground mine stability under higher effective anisotropic stresses ensures safe mining at optimal rates of heading.

Исследования проведены в рамках мероприятия № 1 Комплексной научнотехнической программы полного инновационного цикла, утвержденной распоряжением Правительства Российской Федерации от 11

3D geomechanical model of the Vorkuta Mine, Pechora Coal Basin, has been developed and implemented numerically. By the data on dynamic events recorded by stationary seismic stations, tomography of the study object is performed, and velocity of elastic waves is recovered in the illuminated area of the object. The boundary value inverse problem on horizontal external stresses by stress distribution found using empirical relations between elastic wave velocities and stresses determined in the laboratoryscale experiments is formulated and solved.

The authors have investigated features, forecasting characteristics and interdependence between development of geomechanical processes and acoustic vibration of coal bed and country rock in critical area of formation in the process of forming hazard’s sites of gas-dynamic phenomena. It has been discovered that in the certain combination of physical and mechanical properties of rocks, amplitude-frequency spectrum of vibration source and starting strained and deformed state oscillation process in coal massif can turn into self-vibrating and resonant mode and activate rock burst or sudden coal or gas blowout. V.O. Vakhnenko, O.O. Vakhnenko, J.A. TenCate, T.J. Shankland THE DYNAMICS OF A SANDSTONE BAR UNDER RESONANCE LOADING Subbotin Institute of Geophysics, NAS Ukraine Ukraine, 63-B Bohdan Khmel'nyts'ky Street, Kyiv 01054 E-mail: vakhnenko@ukr.net Bogolyubov Institute for Theoretical Physics, NAS Ukraine Ukraine, 14-B Metrologichna Street, Kyiv 03143 E-mail: vakhnenko@bitp.kiev.ua Los Alamos National Laboratory USA, Los Alamos, New Mexico 87545 E-mail: tencate@lanl.gov, shanklan@lanl.gov