Mont. Code Ann. § 85-1-808

85-1-808 . Changes in lease use not authorized -- cancellation. (1) During the term of a lease, the use of the project lands may not be changed. A change in the use of the lands automatically voids the lease.

(2) The department may cancel a lease for any of the following causes:

(a) fraud, misrepresentation, or concealment of facts relating to issuance of the lease, which if known would have prevented its issuance in the form or to the party issued;

(b) subleasing project lands;

(c) placing of unauthorized improvements on project lands;

(d) using the lands for purposes other than those authorized by the lease;

(e) conviction of the lessee for a felony offense involving a dangerous drug, as defined in Title 50, chapter 32, and involving the planting, propagating, cultivating, growing, harvesting, manufacturing, compounding, converting, producing, processing, preparing, testing, analyzing, packaging, repackaging, storing, or concealing of a dangerous drug on any portion of the lands;

(f) nonpayment of rental fees;

(g) violation of a lease condition;

(h) other causes that in the judgment of the department make the cancellation of the lease necessary in order to do justice to all parties concerned or to protect the interests of the state.

(3) Cancellation of a lease under this section does not entitle the lessee to a refund of rentals paid or exempt the lessee from the payment of rentals, penalties, or other compensation due the state.