Sept 3 (Reuters) - Brazil's Vale conducted its first iron ore sale via blockchain to a subsidiary in China of Nanjing Iron & Steel in what the mining company said was an important milestone towards digitalization of sales.

The letter of credit was issued through Contour's blockchain platform in a procedure that significantly reduced the quantity of e-mails and paperwork, the mining company said.

(Reporting by Anthony Boadle Editing by Chris Reese)