Robert Ross, P.E., Managing Principal, CFO, 20+ years experience As the Managing Principal and CFO of Zipper Geo, Rob oversees the day-to-day operations and financial well being of the Company.  In addition, Rob oversees and manages geotechnical projects. Specialties: Design for mechanically stabilized earth retaining walls,… READ MORE

Thomas Jones, P.E., Senior Consultant, 25+ years experience Speciaties: Geotechnical engineering and pavements associated with large retail projects As a Senior Consultant, Tom serves as a technical resource for employees, business development activities, and project management. And he oversees execution of field exploration, laboratory testing,… READ MORE

Dave Williams, L.G., L.E.G., Principal Engineering Geologist, 30+ years experience Specialties: Geotechnical peer review for local agencies, engineering geology, hydrogeology, critical area characterization, rock slope stability analysis and mapping, slope stability and erosion in the forested environment, LID stormwater evaluations. Dave’s interest in engineering geology was… READ MORE

Sean W. Donnan, P.G., L.G., L.H.G., L.E.G., 30+ years experience: Specialties: Real estate due diligence, site characterization, remedial investigation/feasibility studies, site remediation, redevelopment of contaminated land, litigation support, regulatory negotiation, safety, leadership, program management As Principal Geologist, Sean completes environmental assessment and remediation projects for a… READ MORE

Michael Bullock, P.E., Principal Engineer, 20+ years experience As a Principal Engineer, Michael oversees and completes environmental due diligence, assessment, and remediation projects for clients in the financial, real estate, and energy sectors. Specialties: Due diligence, site characterization, feasibility studies, remediation design, implementation, and operation,… READ MORE

John Zipper, P.E., Senior Consultant, 30+ years experience Speciaties: Geotechnical engineering, geotechnical forensics, geotechnical failure causation, shoring, heavily overconsolidated clays John contributes to our corporate planning and strategic initiatives, gives input on risk management and quality control, and participates in activities with partner organizations and… READ MORE

James Georgis, L.G., L.E.G., Principal Engineering Geologist, 15+ years experience Speciaties: Horizontal directional drilling, pipe ramming, pipe jacking, microtuneling, open shield tunneling, slope stability and slope stabilization, ground improvement As a principal engineering geologist, James manages development, scoping, and completion of a wide variety of… READ MORE

Jon Einarsen, PhD, L.G., L.H.G, L.E.G., Principal Geologist, 20+ years experience Speciaties: Environmental site assessments, contaminate site characterization, remedial investigation and feasibility studies, site remediation, geologic hazards associated with forest practices Jon is the technical leader for environmental services at Zipper Geo, including environmental site… READ MORE

Charles Cacek, L.E.G., M.Sc. – Associate Geologist Chuck has been consulting in the Pacific Northwest for over 25 years.  He has an intimate understanding of environmental due diligence, MTCA regulations, property redevelopment, environmental risk evaluations including cleanup cost estimates, and Pacific Northwest geology. Chuck joined… READ MORE

Jeff Tinklepaugh, L.G., L.E.G., Senior Geologist Jeff joined the ZGA team in October of 2015. He is a licensed Geologist and Engineering Geologist and works in both our geotechnical and environmental groups on a wide range of projects including geotechnical subsurface investigations, Phase I and… READ MORE