Hanson Aggregates Marine is Europe's largest producer of marine-dredged sand and gravel, supplying to a network of wharves in the UK, Belgium, the Netherlands, France and Denmark. Hanson's purpose-built trailing suction hopper dredgers extract sand and gravel from the seabed at depths of up to 50 metres. All vessels are fitted with self-discharging systems which can deliver dry material onto wharves at rates of 600 to 2,600 tonnes per hour. The fleet also includes hydraulic discharge and bottom dump facilities and the company has supplied aggregates to numerous coastal engineering and port development projects.