Geomechanical Assessments of Simultaneous Operation in the Case of Transition from Open Pit to Underground Mine in VietnamZbigniew Niedbalski, Phu Minh Vuong Nguyen and Eleonora Widzyk-CapehartE3S Web Conf., 35 (2018) 01001DOI: https://doi.org/10.1051/e3sconf/20183501001