Rio Tinto will restart a mothballed production line at Tiwai Point aluminium smelter, backed by a new wind farm deal with Contact Energy.The companies signed a letter of intent for a power purchase agreement to support restarting Line 4, which has been idle since 2020. The arrangement would see the smelter become a long-term customer for Contact's recently approved Southland Wind Farm.Line 4 restart would require around 50MW of additional electr…