COMMITMENTS AND CONTINGENCIES Lease Commitments The Partnership leases mineral rights from the U.S. Bureau of Land Management, the state of Wyoming, Rock Springs Royalty Corp, an affiliate of Anadarko Petroleum, and other private parties. All of these leases provide for royalties based upon production volume. The remaining leases provide for minimum lease payments as detailed in the table below. The Partnership has a perpetual right of first refusal with respect to these leases and intends to continue renewing the leases as has been its practice. The Partnership entered into a 10 year rail yard switching and maintenance agreement with a third party, Watco Companies, LLC (Watco), on December 1, 2011. Under the agreement, Watco provides rail-switching services at the Partnerships rail yard. The Partnerships rail yard is constructed on land leased by Watco from Rock Springs Grazing Association and on land by which Watco holds an easement from Anadarko Land Corp; the Rock Springs Grazing Association land lease is renewable every 5 years for a total period of 30 years , while the Anadarko Land Corp. easement lease is perpetual. The Partnership has an option agreement with Watco to assign these leases to the Partnership at any time during the land lease term. An annual rental of $15 thousand is paid under the easement and an annual rental of $60 thousand is paid under the lease. The Partnership entered into two track lease agreements, collectively, not to exceed 10 years with Union Pacific for certain rail tracks used in connection with the rail yard. As of December 31, 2017 , the total minimum contractual rental commitments under the Partnerships various operating leases, including renewal periods, are as follows: (In millions) Leased Land Track Leases Total Minimum Lease Payments 2018 0.10 0.10 0.20 2019 0.10 0.10 0.20 2020 0.10 0.10 0.20 2021 0.10  0.10 2022 0.10  0.10 Thereafter 1.40  1.40 Total $ 1.9 $ 0.3 $ 2.2 Ciner Corp, on behalf of the Partnership, typically enters into operating lease contracts with