060-20 Wyo. Code R. § 20-16
(a) If any trona/sodium lessee defaults in the performance or observance of any of this chapter or any of the terms, covenants, or conditions of the lease under which it is operating, the Board may serve notice of such failure or default either by personal service or by certified or registered mail upon the lessee. If the failure or default continues for a period of thirty (30) days after service of the notice, the Board may declare a forfeiture and cancel the lease, whereupon all rights and privileges obtained by the lessee under the lease shall terminate and the Board may re-enter and take possession of the premises.
(b) This section shall not be construed to prevent the exercise by the Director or the Board of any other legal or equitable remedy which the state might otherwise have nor to relieve the lessee from any accrued obligation under the lease. Failure of the lessor to give notice of default in any particular case or waiver of a particular cause of forfeiture shall not prevent the cancellation and forfeiture of the lease for any other cause of forfeiture or for the same default or cause if it continues or occurs at any other time.
060-20 Wyo. Code R. § 20-16