Mobile drilling platform

From SGCommand

The mobile drilling platform was an underwater drilling station used by the Atlanteans during the War with the Wraith. It was used to drill the floor of the oceans of Lantea, to provide geothermal energy to Atlantis. It was abandoned during when the Atlanteans fled back to Earth. The Atlantis expedition later discovered the station, and used it to supply extra energy when the Asurans attacked Atlantis after the Apollo attacked Asuras, but Rodney McKay anticipated that the station would suffer serious damage when Atlantis left Lantea. (ATL: "Submersion", "First Strike")