Salvage work to remove a capsized rig lying in shallow waters offshore from Angola's new liquefied natural gas (LNG) export plant should be completed by March 2015, the company in charge of the operation said. The three-legged Perro Negro 6 drilling rig overturned last summer as it was being positioned to bore a tunnel for a gas pipeline key to feeding the $10 billion plant. Italian oil services firm Saipem chose South African company Smit Salvage, a unit of Netherlands-based dredging specialist Boskalis, to remove its rig.