A senior official at Nippon Steel & Sumitomo Metal Corp said the company could start talks on a contract for the vessels with Brazilian miner Vale.

Nippon has used the ships seven times in the past, but the move would signal a more settled arrangement.

"We may enter formal negotiations on a freight contract once Kashima gets permissions from authorities and we confirm our plants are ready to receive the ships," Toshiharu Sakae, Nippon Steel's managing executive officer, told Reuters.

Nippon