(1) When tax is imposed. A conditional sale of mining property in which the grantee has the right to terminate the contract at any time, and a lease and option to buy mining property in which the lessee/grantee has the right to terminate the lease and option at any time, is taxable at the time of execution on the amount of the consideration paid to the grantor/lessor for execution of the contract. The tax due on any additional consideration paid by the grantee and received by the grantor is paid to the county upon the first occurrence of the following events:

(a) The time of termination;

(b) The time that all of the consideration due to the grantor has been paid and the transaction is completed except for the delivery of the deed to the grantee; or

(c) The time when the grantee unequivocally exercises an option to purchase the property.

(2) Lease for royalty. A mining lease that grants the lessee the right to conduct mining exploration upon or under the surface of real property and to remove minerals from the property in exchange for a royalty is not subject to the real estate excise tax when the lease does not transfer ownership of the minerals to the lessee prior to severance from the real property.

(3) Patented claims. Patented mining claims are real property and their sale is subject to the real estate excise tax.

(4) Unpatented claims. Unpatented mining claims are intangible personal property and therefore not subject to the real estate excise tax.