Technology in the (Ocean) Trenches

Heavy-duty mining robots can now dig for gold in rocky, underwater landscapes at depths of as much as two kilometers. Earlier this year, a Canadian company, Nautilus Minerals, dispatched a specially designed underwater mining robot to conduct the world’s first commercial deep-sea search for gold and copper, off the coast of Papua New Guinea in a mountainlike landscape 1,600 meters below sea level.

The feat was made possible through a marriage of advanced 3-D mapping technology and heavy-duty mining gear. Nautilus started with a deep-sea ROV (remotely operated vehicle) normally used by the oil and telecom industries; the company customized it by adding drilling and cutting tools hitherto used only on land.

Nautilus also equipped the ROV with a multibeam sonar device that maps the landscape in real time; software combined the device’s reports with ROV location data to present a graphical display to an ROV pilot in a surface ship above the drilling site. Using the display, the pilot guided the ROV through the first mining operation in the cold, dark, and craggy underwater environment. “This software allows us to view the real-time location of our ROVs and ship in relation to the mapped features of the ocean floor,” says Tim Searcy of Nautilus Minerals.

The company is evaluating its findings and preparing to follow up with a bus-sized, 750-horsepower ROV, and possibly a 1,000-horsepower model – which would be one of the world’s largest ROVs – made by Perry Slingsby Systems, to do full-scale mining in the same area off Papua New Guinea, where sulfur vents on the ocean floor leave valuable mineral deposits.