In Buenos Aires, Argentina, under contract to Impregalla Healy, AUS provided consulting, design, and direct supervision of underwater concrete placement in the four drop shafts required for the implementation of the tunnel machine. AUS was involved in the development of the underwater requirements including the safety plan, excavation, survey, rebar, and drain installation components in 165 feet of water utilizing wet divers. AUS worked closely with the local dive company to ensure safe and competent placement of underwater components. AUS had a direct supervisory role in placing 2,800 cubic meters of concrete in 4 shafts using a floating concrete tremi system (referred to as the DOBBER system). The work took place over a two-month period with AUS personnel on-site.