Tunneling and Underground

The purpose of the Tunneling and Underground committee is to identify and facilitate the advancement of new methods and technologies for design, construction, inspection, maintenance and operation of tunnels and underground systems.

Committee Chairs

headshot of stier

Co-Chair

Robert Stier
Drill Tech Drilling & Shoring, Inc.

In 2018 Bob Stier joined Drill Tech Drilling & Shoring (DTDS) and brought with him with over 35 years of tunneling and underground experience to oversee Drill Tech’s Eastern Region. DTDS is a leader in specialty geotechnical construction industry and performs tunneling operations throughout the United States.  In the three years he has been a part of DTDS, he helped procure tunnel projects on both the West and East coasts of the U.S. and has procured and managed Drill Tech’s first foundation projects in the eastern region.  Under his guidance Drill Tech procured its largest GC Design-Build Contract for National Parks Service and he is currently managing the project.

Prior to joining DTDS Stier worked as area manager for various tunnel construction companies.  He has overseen various tunneling operations including conventional drill-and-blast tunnels, pressurized face operations, and hard rock tunnel boring machine (TBM) and micro tunnel projects. He has both direct field supervision and project management experience on major underground projects across the nation.

Stier graduated from Southern Polytechnic State University (Kennesaw State) in Marietta, Georgia with a bachelor’s of science in civil engineering technology.

headshot of fippin

Co-Chair

Renee Fippin, P.E., G.E.
Delve Underground

Renée L. Fippin, P.E., G.E., is a principal engineer at Delve Underground in the Walnut Creek, California, office. She is a registered Geotechnical Engineer in California, and a registered Professional Engineer in California, Massachusetts, North Dakota and New York. She earned her bachelor’s degree in engineering physics from Miami University.

Fippin’s expertise spans both geotechnical and structural engineering, including a thorough background in the design of shafts and tunnels, and with investigation and evaluation of new tunnels as well as existing tunnels for rehabilitation. Her combined detailed design and management experience, along with geotechnical and structural background, have given her unique insights to understand how to efficiently plan a project from initial to final design phases.

She is on the board of directors for Delve Underground and has published numerous papers for the Underground Construction Association of the Society of Mining, Metallurgy & Exploration. Her most recent paper is “Flood Resilience in San Francisco.”

Committee Initiatives

Browse our initiatives, both complete and ongoing.

Scroll to Top