Dr. Sopko has 40 years of experience in Artificial Ground Freezing, twenty of which were combined with the design and construction with construction dewatering systems. He is currently the Director of Ground Freezing for Keller and oversees ground freezing for civil and mining projects world-wide. He is also an adjunct professor at Michigan State University in East Lansing, Michigan where he teaches a ground improvement course concentrating on ground freezing and dewatering. Major ground freezing projects that he and the team of Keller engineers and craftsmen include the No. 7 Line Subway in New York City, Northgate Link Subway in Seattle and currently two deep shafts for Water Tunnel No. 3 in New York City. He is the chairman of the ASTM subcommittee on the testing of frozen rock and soils.