Saffet Yagiz received a PhD from the Colorado School of Mines (CSM), USA. His main research interests are engineering rock mechanics; mechanized excavation and tunnelling, rock characteristics and testing; geology and geotechnical. He has authored over 100 publications including peer-reviewed scientific journals, proceedings, industrial project reports and books. He is a recognized reviewer of many mining and geotechnical journals and also, Editorial Board Member of Tunnelling and Underground Space Technology. He is known for the studies of developing the Modified CSM Model for estimating Tunnel Boring Machine (TBM) penetration, TBM performance prediction formulas, and also proposing rock brittleness index & classification.