Homework (mining topic) I have to present something in my class, it's about tunneling. I wrote something but I want to know if I am right, made a mistake or I can say the same in a better way. -The side drift method involves the excavation of two predriven side drifts with the subsequent placement of a concrete lining. the latter serves as a foundation for the lining in the heading. The placement of the invert arch, it means, the closure of the lining follows inmediately after the excavation of the core.