Bibliographische NotizFunding Information:
The first author (FHN) thanks OeAD, Austria's Agency for Education and Internationalization , for an Ernst Mach Grant, ASEA-UNINET scholarship (Reference number: ICM-2019-13766 , MPC-2020-01500 , MPC-2021-01331 ). FHN would also like to thank PT. Adaro Indonesia Company for their help in sampling the coal seams. The paper benefitted greatly from the very detailed and positive criticism of the journal reviewers Tim A. Moore and Cortland F. Eble.
© 2022 The Authors