A Vale SA vessel leased from STX Pan Ocean Company has been found to have a leak in a ballast tank just two months after being delivered.

The ship docked at a Brazilian port was intended to transport as much as 400,000 metric tons of iron ore to China and will now undergo repairs to fix the leak.

The leak was discovered while the $110m vessel was being loaded with 381,300t of iron ore, worth $53m, at Ponta da Madeira port in Brazil.

The company said it is investigating the cause of the leak and plans to move the ship for repairs shortly.

Vale Beijing ship is the first in a fleet of eight that STX will operate under a $5.8bn 25-year deal with the Brazilian mining firm.

Det Norske Veritas, which monitors compliance ships’ design and structural rules, has already discussed technical issues with the owners.

STX Group said there will be no delays in deliveries and the next delivery is scheduled for later this month. Four ships are due in 2012 and two in 2013.

Earlier this year, another Vale vessel, the Vale Brasil, had to turn around in the Indian Ocean on its maiden voyage after the Chinese Government failed to provide permission for the giant ship to dock at Dalian.

The builders of the other vessels in Vale’s planned fleet include Daewoo Shipbuilding & Marine Engineering and China Rongsheng Heavy Industries Group Holdings, which won a combined 19 orders directly from the iron ore producer.

The Brazilian firm intends to eventually control 35 mega-ships to pare risks from fluctuating freight rates to China.