What happened

Shares of Cliffs Natural Resources (CLF 0.19%) rocketed on Thursday and were up more than 16% by 2:30 p.m. EST after the iron ore miner reported expectation-beating fourth-quarter results.

So what

Cliffs Natural Resources reported revenue of $754 million during the fourth quarter, up 58% from the year-ago quarter thanks to higher volumes and pricing, which was $78.8 million ahead of analysts' expectations. Earnings from continuing operations, likewise, surged to $81 million, or $0.42 per share, putting last year's net loss of $58 million in the rearview mirror. Meanwhile, even after factoring out an $0.08-per-share loss from discontinued operations, Cliffs blasted past the consensus estimate by $0.11 per share. As a result of that strong showing, Cliffs' full-year adjusted EBITDA came in at $374 million.

Loading of iron ore on very big dump truck.

Image source: Getty Images.

However, as good as 2016 was, Cliffs expects 2017 to be even better. The company sees U.S. iron ore sales volumes rising 4.3% this year to 19 million tons. As a result of those volumes, and its expectation for steady pricing of iron ore and steel, the company expects adjusted EBITDA to more than double this year to $850 million. It also ended last year with just $1.8 billion of net debt, down from $2.5 billion at the end of 2015.

Now what

After several tough years, the iron ore market appears to be getting back on its feet. That's all Cliffs needs right now since its bullish outlook only requires pricing to hold at last month's levels. Because of this, it could easily exceed expectations if pricing continues to improve. However, if prices start to slide, it could quickly sour that outlook.