Wyo. Stat. § 18-4-309
The board of county commissioners shall annually levy upon all taxable property in the county, in addition to other authorized taxes, a sufficient sum to pay the interest on all bonds and shall at least five (5) years before the bonds become optional, and in time to provide means for their payment, annually levy not less than one (1) mill to pay the bonds as they become optional. All such taxes shall be levied, assessed and collected as other county taxes until the bonds and interest are fully paid. Should the tax for payment of interest on bonds issued not be levied or collected in time for payment the interest shall be paid from monies in the general fund of the county and the money so used shall be repaid to the general fund out of the first monies collected from taxes.
W.S. 18-4-309