CHEYENNE, Wyo. (AP) — Wyoming Oil and Gas Supervisor Grant Black has submitted his resignation.The Wyoming Oil and Gas Conservation Commission made up of Gov. Matt Mead and four other state officials accepted Black's resignation Monday after a nearly two-hour conference call.

The commissioners then named longtime commission employee Mark Watson to serve as interim supervisor once Black's resignation takes effect Tuesday.

Why Black is resigning after 11 months on the job isn't clear. Most of the conference call was closed to the public and neither Black nor Mead spokesman Renny MacKay immediately returned messages seeking comment.

The oil and gas supervisor and the five commissioners oversee oil and gas development in Wyoming. The commission has been considering several significant changes to Wyoming's oil and gas regulations in recent months.