SunCoke Energy Inc

7. Intangible Assets

Intangible assets, net, include goodwill allocated to our Domestic Coke segment of $3.4 million at both December 31, 2023 and 2022, and other intangibles detailed in the table below, excluding fully amortized intangible assets. There wereno changes in the carrying amount of goodwill during the fiscal years ended December 31, 2023 and 2022, respectively.

The permits above represent the environmental and operational permits required to operate a coal export terminal in accordance with the U.S. Environmental Protection Agency (“EPA”) and other regulatory bodies. Intangible assets are amortized over their useful lives in a manner that reflects the pattern in which the economic benefit of the asset is consumed. The permits’ useful lives were estimated to be 27 years at acquisition based on the expected useful life of the significant operating equipment at the facility. We have historical experience of renewing and extending similar arrangements at our other facilities and intend to continue to renew our permits as they come up for renewal for the foreseeable future. The permits were renewed regularly prior to our acquisition of CMT. These permits have an average remaining renewal term of approximately 5.4 years.

Total amortization expense for intangible assets subject to amortization was $2.1 million, $2.0 million and $2.0 million for the years ended December 31, 2023, 2022 and 2021, respectively. Based on the carrying value of finite-lived intangible assets as of December 31, 2023, we estimate amortization expense for each of the next five years and the aggregate amount thereafter as follows: