According to USA Today, she said the price of Wyoming coal had dropped from $14 a ton to just $6/t over the past six months due to low natural gas prices and falling demand from power plants.

While local coal producers are still selling coal at higher prices, she reportedly expressed concern to a forum at Laramie that new fixed contracts would be negotiated around much lower spot prices.

Impacts could be wider than anticipated as Wyoming depends on billions of dollars of coal royalties and taxes.

Meanwhile, Asian demand for Australian thermal coal remains steady.

Indexed spot prices for Newcastle exported thermal coal were about $105 per metric tonne at the end of March.