Vale SA is expected to report a second straight quarterly decline in iron-ore output as the world’s biggest producers forgo volume for higher grades and lower costs after prices fell for three years. The Rio de Janeiro-based company produced 90.3 million metric tons in the third quarter including third-party purchases, down from 90.7 million in the year-ago period, according to the average estimate of five analysts surveyed by Bloomberg News. Vale is scheduled to release its production report before the start of trading on Thursday. After years of expanding supply to meet rising demand from Chinese steel mills, Vale and its largest rivals Rio Tinto Group and BHP Billiton Ltd. are focusing more on containing costs and protecting margins after a slowdown in demand led to oversupply and slumping prices. That’s bringing into question Vale’s ability to post another annual output record as it finishes development of the industry’s biggest project. “Vale is trying to finish a major project,” Andrew Keen, an analyst with Haitong Securities, said by telephone. “To push out that extra tonnage just to hit a production target is not the greatest way to create value.” In July, Vale said it was on track to come in at the lower end of a 340 million to 350 million-ton output guidance range for 2016. It produced 346 million tons in 2015, including third-party purchases. The $14-billion S11D project in Carajas, northern Brazil, will start shipping ore early next year as part of Vale’s efforts to bring down costs and reduce its geographical disadvantage with BHP and Rio, whose Australian mines are much closer to China. Chief Executive Officer Murilo Ferreira is also streamlining operations and selling assets after the company racked up a massive debt load when commodity prices were booming. Iron ore has slumped about 70 percent from a 2011 peak to about $58 a ton now. Prices probably will be stuck at around $50 through 2018, according to the average estimate among analysts tracked by Bloomberg. Still, prices have recovered 34 percent this year. A 1 trillion yuan ($150 billion) influx into Chinese infrastructure spending through a 2017 public-private partnership program, coupled with more measured output from the major producers could prop up prices through next year, according to Bloomberg Intelligence. On Tuesday, BHP reported a 6 percent decline in quarterly iron-ore production as it carries out a rail maintenance program, has lower volumes from its Yandi mine and with its Brazilian joint venture with Vale halted. Production slid to 57.6 million tons in the three months ended Sept. 30 from 61.3 million tons a year earlier. Rio Tinto is scheduled to release its quarterly operations review at 5:30 p.m. New York time Wednesday.