Dr. Topias Siren has worked as a rock engineering and rock mechanics consultant since 2008. His projects have included the rock mechanically the most demanding projects in Finland. Between 2011 and 2015 he was in charge of rock mechanics research for the Finnish underground repository for spent nuclear fuel. Major part of the work was conducting an in situ experiment at the depth of -345 m to determine the rock strength and the development of new rock characterization techniques. At that time a new rock stress measurement technique based on shallow overcoring from tunnel surface was developed. He was in charge of a project that evaluated that the new technology produced reliable rock stress measurement results. Since then he has been involved in rock stress measurements with the new technique in deep mines up to -1400 m. His dissertation thesis demonstrated that in high stress conditions deep underground a stress-induced excavation damage zone (EDZSI) exists and that structural features control the rock mass strength at the nuclear waste disposal site in Olkiluoto. He is the Chairman of the Board of Stress Measurement Company and Rock Mechanics Consulting Finland providing expert services to Mining companies and SNF management organizations, and has a post as post-doctoral researcher at Aalto University. His research topics include Time-dependent and Mechanical behaviour of brittle Crystalline rocks; Underground Thermal energy storages; and On-line Risk Management in Deep Mines.