An interest in a mineral property that entitles the owner of that interest to all of share of the mineral production from the property, usually subject to a royalty. A working interest permits the owner to explore, develop, and operate the property. The working-interest owner bears the costs of exploration, development, and operation of the property and, in return, is entitled to a share of the mineral production from the property or to a share of the proceeds therefrom. It may be assigned to another party in whole or in part, or it may be divided into other special property interests.

• Gross working interest. The reporting company's working interest plus the proportionate share of any basic royalty interest or overriding royalty interest related to the working interest.
• Net working interest. The reporting company's working interest is not including any basic royalty or overriding royalty interests.