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., Jan Blachowski, Steinar Ellefmo and Erik Ludvigsen., and Obsahuje bibliografii
Combination of numerical models of deformations and repeated geodetic measurement results provide reliable information on the state of the rock mass in a mining area and support planning and control of the mining operation. The paper describes the concept of integrated monitoring and analysis of rock mass deformation in the Kvannevann iron ore mine (Norway) using sub-level caving (SLC) method. Geodetic control network developed for periodic measurements of surface subsidence and a source of geometrical data for numerical modelling of deformations using finite element method (FEM) has been characterised. Focus is given to the results of initial numeric al analyses with FEM of rock mass deformations due to SLC mining. The results of the modelling provided information on possible extent of deformation zones on the mining ground surface once mining with new method commences., Jan Blachowski and Steinar Ellefmo., and Obsahuje bibliografické odkazy