Geodynamic Safety of Mining Operations under Rockburst-Hazardous Conditions in the Khibiny Apatite Deposits

The results of investigations aimed at solving the topical problem of geodynamic risk assessment in mining of the Khibiny rockburst-hazardous deposits in the Kola Peninsula are presented. The developed procedures and approaches contribute to minimization of geodynamic risks under large-scale mining of close-spaced apatite-nepheline ore deposits. The geomechanical model is designed, which allows analyzing successive development of a system of closely spaced deposits in the Khibiny Massif. Based on the model data on the stress-strain state, the optimal sequence and direction of mining in the conditions of rockburst hazard is determined. The nested structure of the rock mass, direction of the tectonic compression, main radial faults, daylight surface relief and the parameters of the ore bodies are taken into account. The complexing of the predicted stress fields and seismicity improves reliability of detection of higher rockburst hazard zones. The examples of stoping sequence substantiation using a set of in-situ and numerical methods are given. The main lines of development in the geomechanical support of mining and the variants of process solutions toward regional and local unloading of rock mass are shown.