SAO PAULO--Brazilian mining company Vale SA (VALE, VALE5.BR) sold $1.5 billion in 30-year bonds, after seeing investor demand for the debt issue of three times the amount offered, a market source said Tuesday. Vale, the world's largest miner of iron ore and second-biggest nickel producer, priced the 30-year bonds maturing 2042 at a yield equal to U.S. Treasuries plus a spread of 3 percentage points, the market source said. Vale, which the source said earlier in the day was seeking to raise $750 million in the bond sale, said it will use proceeds for general corporate purposes. The bond sale comes as tensions appear to be easing in global financial markets and at the end of the Northern Hemisphere summer, which typically sparks a wave of bond sales as investment bankers return from vacation. --Paulo Winterstein contributed to this report. Write to Rogerio Jelmayer at Rogerio.Jelmayer@dowjones.com Subscribe to WSJ: http://online.wsj.com?mod=djnwires