MONITORING SYSTEM FOR OBSERVATIONS OF ROCK MASS DEFORMATIONS CAUSED BY SUBLEVEL CAVING MINING SYSTEM

摘要

The Rana Gruber iron oxide mining company in Norway has started to develop a new underground production level in order to continue operation in the Kvannevann mine. The planned change of mining system to sub-level caving (SLC) involves the removal of protective pillars below the former Kvannevann open-pit. Surface deformation on the hanging-wall and footwall sides of the deposit and caving of rock into the old pit is expected. When uncontrolled, this represents a threat to the underground mining operation below the open-pit. Trial removal of the protective pillar in the western part of the deposit has already caused fracturing of the rock mass on the hanging-wall side. Therefore, with the aim to monitor and control the rock mass deformation process in this area and ensure safe operation of the mine, a monitoring system based on periodic total station and GPS measurements in a three-tier control-measurement network has been developed and tested. In this paper the concept of this system, results of field work and recommendations for the system implementation is presented. The proposed concept has been used to implement a real system in the mine.