Application of InSAR for monitoring deformations at the Kiirunavaara Mine

An integral part of sublevel cave underground mining is the associated caving of the surrounding host rock. This causes mining-induced ground surface deformations on both the hangingwall and footwall side of the orebody. The municipality of Kiruna, in northern Sweden, is located in close proximity to the LKAB Kiirunavaara mine and is thus unavoidably affected by the mining activities. To be able to plan for an urban transformation, as the effects of mining approach the city infrastructure, it is necessary monitor the ground deformations on a regular basis. Historically, GPS-monitoring has been used, with an extensive network of measurement hubs in place. New techniques for monitoring ground deformations are, however, constantly evaluated. As part of this process, LKAB has conducted a five-year research and development project on deformation measurements using radar satellites and the InSAR technology. The project has included a monitoring component and a research- and technology transfer component. The overall findings of the monitoring program, and the associated research and development work are presented. Particular emphasis is put on achieved accuracy and the implications for the ability to reliably monitor the progressing deformations toward the municipality and existing infrastructure. Lessons learnt from the conducted work are presented, followed by recommendations on future use of InSAR for this type of application.