ABSTRACT
The article presents the research results of the Mining Institute of the Kola Science Centre RAS in the field of geomechanical support of mining operations at the rockburst-hazardous deposits of the Kola Peninsula for recent years. The methods developed help minimizing geodynamic risks when conducting large-scale underground and open mining operations. The authors consider examples of justification of the order of carrying out stoping operations with the use of complex full-scale and numerical methods. The main directions have been shown of development of geomechanical support of operations, variants of technological solutions leading to unloading of the rock mass sections, as well as local measures to reduce the level of acting stresses in the boundary zone of mine excavations. A brief analysis is given of powerful seismic events, tectonic rockbursts and mining-induced earthquakes.
The results of a prognostic study of geomechanical processes associated with a change in the stress-strain state during the mining of the adjacent deposits at the Khibiny apatite arc are presented. The authors outline a methodical approach to the development of a complex of multiscale numerical models of a volumetric stress-strain state (SSS) of a rock massif with the possibility of differentiated or complex accounting of the main geological and mining factors on the example of creating a geomechanical model of the Khibiny ore mining district. A geomechanical model has been created that allows considering the development of the complex of the adjacent Khibiny deposits and determining the order and direction of mining operations in rockburst-hazardous conditions, taking into account the enclosed ring structure of the rock massif, the effects of tectonic stresses, major radial faults, the relief of the surface, and parameters of ore bodies. Specific features of the stress-strain state in the Khibiny rock massif with successive excavation of the ore apatite-nepheline deposits confirm the hypothesis of transformation of the SSS types with depth and reorientation of the principal stresses in the blocks of the rock mass between the radial faults. The absolute altitude marks −1000 ÷ −1200 m have been defined, below which the vertical stresses prevail over the horizontal ones. The obtained results indicate that all the proven reserves of the Khibiny apatite arc will be worked out in conditions of evident tectonic compression of the rocks. It is possible to use the results obtained in making decisions on the development of other adjacent deposits in complex geomechanical conditions.
