A guard ship and helicopters of the South Korean maritime police conduct an exercise to remove crude oil on the sea off Taean, about 150 km (93 miles) southwest of Seoul December 11, 2007. Thousands of soldiers, police and volunteers have been working for days to remove 10,500 tonnes of oil from Hong Kong-registered oil tanker Hebei Spirit after a crane mounted on a Samsung-owned barge punched holes in its hull last Friday. [Agencies]