Brazil’s Vale (NYSE:VALE) kept ramping up its production of iron ore in the October-to-December period despite a global glut that has severely hurt producers and squeezed smaller competitors.

The iron ore giant, however, posted an unexpected decline in quarterly output, which fell to 85.4 million metric tons from 88.2 million in the third quarter. While output excluding third-party purchases and operations at a venture with BHP Billiton was up from 83 million in the period, it missed the 88.3 million-ton average of seven analyst estimates compiled by Bloomberg.

Vale closed 2015 with total production of 345.9 million tons, a company record and a 4.3% rise from the previous year.

The Rio de Janeiro-based miner closed 2015 with total production of 345.9 million tons, a company record and a 4.3% rise from the previous year.

The output increase came despite the suspension of its Samarco joint venture with BHP after a tragic dam break Nov. 5 in Mariana, Brazil. The mine disaster killed 19 people and caused production to fall 39% in the fourth quarter to 6.3 million tons.

“To compensate this lost production at the Mariana complex, mitigation measures were immediately implemented to improve performance at other operations,” the company said in a news release. As a result, Vale’s iron ore output in 2015 surpassed its target by 5.9 million tons.

Vale, which is also the world’s larger nickel producer, produced 82,700 tonnes of nickel, up 12% when compared to the third quarter. Copper output was up 6.7% in the quarter at 112,500 tons

The company is scheduled to release financial results on February 25.

• [Editor:Juan]