NOTE 8—LEASES

Operating Leases—We lease facilities under various noncancelable operating lease agreements. Our leases have remaining lease terms of less than two years. Operating lease expense for facilities totaled $0.2 million, $0.2 million and $0.1 million in 2020, 2019 and 2018, respectively.

At December 31, 2020 and 2019, operating lease ROU assets totaled $0.1 million and $0.2 million, respectively. Operating lease liabilities at December 31, 2020 totaled $0.1 million. Of this, $31 thousand is included in other long-term liabilities within the consolidated balance sheets. Operating lease liabilities at December 31, 2019 totaled $0.2 million. Of this, $0.1 million is included in other long-term liabilities within the consolidated balance sheets.

Maturities of operating lease liabilities are as follows:


(In thousands)
Years ending December 31:
2021	$	98
2022		41
Total lease payments		139
Less imputed interest		(29)
Total	$	110

As of December 31, 2020, the weighted average remaining lease term was 1.3 years and the weighted average discount rate used in computing the lease obligations was 8.5%.

Coal Leases and Associated Royalty Commitments—Leases of mineral reserves and related land leases are exempted under U.S. GAAP from recognition within the financial statements. We lease coal reserves under agreements that require royalties to be paid as the coal is mined and sold. Many of these agreements require minimum annual royalties to be paid regardless of the amount of coal mined and sold. Total royalty expense was $11.8 million, $15.6 million and $11.6 million for the years ended December 31, 2020, 2019 and 2018, respectively. These agreements generally have terms running through exhaustion of all the mineable and merchantable coal covered by the respective lease. Royalties or throughput payments are based on a percentage of the gross selling price received for the coal we mine. Payments of minimum coal royalties and throughput payments for leases with Ramaco Coal, LLC commenced in 2017 pursuant to the terms of the agreements.

Future minimum lease and royalty payments for each of the next five years and thereafter are as follows:


(In thousands)
Years ending December 31:
2021	$	5,297
2022		5,709
2023		5,720
2024		5,719
2025		5,719
Thereafter		12,352
Total minimum payments	$	40,516