Dr. Gall is a principal of Gall Zeidler Consultants, a global specialty tunnelling and underground engineering firm. He has over thirty years of experience in the design, construction, and construction management of tunnels and underground structures. His expertise encompasses soft ground, mixed-face, and rock tunneling utilizing TBM, conventional tunnelling, and cut-and-cover techniques. He frequently serves on expert review panels dedicated to the investigation and improvement of tunneling schemes. He is active in various tunnelling associations including the International Tunnelling Association, (ITA), The Underground Construction Association (UCA) in the US, and the International Society for Rock Mechanics. He has authored numerous peer reviewed papers, lectured in various tunnelling short courses, and he is presently serving as the vice animateur of ITA Working Group 19, “Conventional Tunnelling.