Arch Coal Inc, one of the world's top five coal producers, reported a surprise profit as cost cuts paid off, and the company said thermal coal shipments were improving.
Net profit rose to $45.8 million, or 22 cents per share, in the third quarter, from $8.9 million, or 4 cents per share, a year earlier. Excluding items, profit was 20 cents per share.
Revenue fell 9 percent to $1.09 billion.
Analysts on average had expected a loss of 16 cents per share on revenue of $1.01 billion, according to Thomson Reuters I/B/E/S.
Arch Coal shares rose nearly 7 percent in trading before the bell on Friday.