011-6 Wyo. Code R. § 6-9
(a) The fair market value of the gross product shall be determined at the point at which the mining or production of the mineral is completed. Unless otherwise provided by law, the mining or production of the mineral shall be considered completed at the point of valuation as provided by W.S. 39-14-101(a)(vi) for coal, W.S. W.S. W.S. 39-14-203(b)(iu) for crude oil or lease condensate, W.S. W.S. W.S. 39-14-203(b)(vi) for natural gas, W.S. W.S. W.S. 39-14-301(a)(iv) for trona, W.S. 39-14A0\ (a)(vi) for bentonite, W.S. W.S. W.S. 39-14-501(a)(vi) for uranium, W.S. W.S. W.S. 39-14-601(a)(vi) for sand and gravel, W.S. W.S. W.S. 39-14-701(a)(vi) for other valuable deposits.
(b) When a solid mineral is sold at the point of valuation pursuant to a bona fide arm's-length sale, the sales price shall be the fair market value.
(c) When a solid mineral, for which there is no specific statutory valuation method, is sold at a point other than the point of valuation, the fair market value shall be determined by the Department in accordance with recognized appraisal techniques.
(d) When a solid mineral other than coal is not sold pursuant to a bona fide arm's-length sale, or is used without sale, the fair market value shall be determined by the Department in accordance with recognized appraisal techniques.
011-6 Wyo. Code R. § 6-9