ABSTRACT
The paper presents the studies of the geomechanical state of the rock mass in the Oleniy Ruchey deposit. Based on the results obtained, the authors have substantiated an optimal order of underground mining operations as well as the safe parameters of open stoping mining which is planned to be used here.
The Oleniy Ruchey apatite-nepheline deposit is located in the south-eastern area of the Khibiny rock massif (Kola Peninsula, Russia) and represented by several closely located ore bodies, thickness of which increases with depth. The deposit is attributed to the inclined ones. From the 400 m depth it is considered to be a rockburst-hazardous deposit.
Due to the deposit’s geological features, the first stage of underground mining will involve the use of open stoping with the subsequent transition to sublevel caving mining.
The justification of the parameters for stopes and pillars between them is based on the results of analytical calculations and numerical modeling of the stress-strain state of the rock mass. Modeling was carried out taking into account the tectonic stresses in the rock mass, differences in ores and rocks properties, and mountainous surface topography with the consequent progress of underground stoping operations.
The boundary conditions were set based on the measurement of the stresses in the intact rock mass. For calculations, the software SigmaGT, developed at the Mining Institute KSC RAS, was used.
The results received evidence the potential in applying the open stoping mining method with size of the rib and level pillars of 20 m and 25 m, respectively.
