In the energy world, it's never much of a surprise when an oil company picks up natural gas assets or vice versa. But a coal company getting into the oil business? Now that's a rarity. This week, Natural Resources Partners (NRP 1.23%) did just that. The company announced that it's taking a working interest in some of Abraxas Petroleums (AXAS) assets in the Bakken. While the $35 million purchase was not that large, it's a rare case where a coal company branches out into other natural resources. 

Since Natural Resources doesn't have the access to the export markets like some of the larger players in the coal market, it actually makes sense for this coal company to branch out. In this video, Fool.com contributors Tyler Crowe and Aimee Duffy discuss why this kind of move could make sense for some domestic coal producers.