GILLETTE, Wyo. (AP) — The spot price for Powder River Basin coal hit a two-year low this week.

On the informal, over-the-counter market, coal contracts for April delivery sold for $6.50 a short ton on Monday. That’s the lowest level since Sept. 29, 2009.

For perspective, Powder River Basin spot contracts for next month delivery reached $16.35 in February 2008.

Charlie Noh, of Platts Coal Group, tells the Gillette News Record ( ) that PRB coal is selling low because of the warm winter and lower natural gas prices.