Chengjin Gu is a PhD student in Mining Engineering at the China University of Mining and Technology–Beijing (CUMTB), currently as a visiting researcher at CERENA, IST, University of Lisbon. His research focuses on managing mining solid waste, developing cemented paste backfill materials, and utilising underground spaces. He is particularly interested in CO₂ sequestration and mineralisation in cementitious materials, as well as geothermal energy recovery from mined-out areas. His current work contributes to advancing low-carbon and sustainable mining technologies.