THE SURFACE MINER SUSTAINABLE TECHNOLOGY INTRODUCTION FOR OIL-SHALE MINING IN ESTONIA. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference, [S. l.], v. 1, p. 55–61, 2007. DOI: 10.17770/etr2007vol1.1735. Disponível em: https://archive-journals.rtu.lv/etr/article/view/3631.. Acesso em: 11 mar. 2026.