SHERIDAN, Wyo. (AP) — Several hundred coal miners have lost their jobs at mines along the Wyoming-Montana border, even as global coal markets are enjoying a heyday.

A dispute over West Coast ports hobbles the industry's ability to reach booming markets in Asia.

Workers like 41-year-old Mike Cooley are looking for work as a rise in natural gas production reduces the domestic demand for coal. The 41-year-old thought his job as a "powderman" at the Decker strip mine would take him into retirement.

For decades, the 25,000-square-mile Powder River Basin that surrounds Sheridan, Wyo., has been the stronghold of the U.S. coal industry.

But the depressed domestic coal market is finally catching up to mines such as Decker. Federal mine regulators say a t least 300 jobs have been lost from mines in Montana and Wyoming since early 2012.