Falling coal prices dented fourth-quarter revenue at Arch Coal (ACI), but ACI stock surged about 5% in Tuesday morning trading after company officials said coal prices would stabilize this year.

The coal price comments came during a conference call discussing the quarterly results. ACI executives said that rising natural gas prices, improved business activity and changing weather patterns would cause thermal coal markets to grow more competitive in the U.S. in 2014, theflyonthewall noted.

ACI stock gained even after the mining company reported a loss of $371.2 million for the December quarter. That’s worse than the loss of $295.4 million posted by ACI in the year-ago quarter. Excluding a non-cash goodwill impairment charge of $265.4 million, ACI reported an adjusted loss of $95.1 million or 45 cents per diluted share. That exceeded the loss of 39 cents a share that Wall Street had predicted for ACI, the St. Louis Post-Dispatch noted.

Sliding prices for metallurgical and thermal coal sent ACI revenue down to $719.4 million, a 17% decline from the prior-year quarter. That was lower than the revenue of $767 million anticipated by analysts. Disruption with ACI railway deliveries also pressured revenues.

ACI stock has declined more than 40% over the past year as the company reported seven consecutive quarterly losses. ACI stock closed at $4.01 a share on Monday.