RIO DE JANEIRO, Jun 19.  -- Brazilian mining company Vale SA (VALE, VALE5.BR) said Monday a Valemax iron ore vessel--one of seven large iron ore carriers currently operated by Vale--docked in Japan for the first time.

The vessel, named the Berge Aconcagua, transported ore to Oita port for Nippon Steel Corporation (NSC), Vale said in a statement.

Valemax vessels can carry 400,000 metric tons of iron ore. Vale has encountered difficulties docking Valemax vessels in China--where several of the vessels are being built--due to resistance from Chinese shipowners and alleged port handling capacity problems.

Carbon emissions from Valemax vessels are 34% lower per ton of ore carried than emissions from conventional ore carriers, which have capacity to transport around 200,000 tons of ore at a time, Vale said. This is because the larger vessels use more modern equipment that consumes less diesel fuel, Vale said.