Coal Royalty Fairness Act of 2015

Coal Royalty Fairness Act of 2015

Amends the Mineral Leasing Act to require the coal lease royalty to be at least 12.5% of the assessment value of federal coal (currently, 12.5% of the value of coal as defined by regulation), which value shall be established by the Secretary of the Interior within one year after enactment of this Act.

Defines "assessment value" as: (1) the price of federal coal paid by the purchaser at final sale, or (2) a price imputed by the Secretary based on the coal price index. Defines "coal price index" as the schedule of average market prices of federal coal paid by the purchaser at final sale, based on the quality and type of the federal coal, as determined by the Secretary.

Directs the purchaser of federal coal to annually submit a report containing such information as the Secretary determines necessary to carry out this Act. Authorizes the Secretary to examine the records of any person engaged in the purchase, sale, transportation, or marketing of federal coal. Directs the Secretary to: (1) compile the assessment values of coal by type and quality of coal in the coal price index, and (2) publish such index at least quarterly.

Sets forth provisions regarding: (1) determining and assessing royalties for the export of federal coal, (2) compiling in a transportation cost index the average costs of transporting coal, and (3) determining the amount of any applicable transportation cost deduction on the basis of such index. Requires the Secretary to publish such index at least twice annually.

Requires the Comptroller General to report to Congress every 3 years over a 15-year period on a review of the federal coal program.