Ramadhan, Satrio, Silky Amanda Yuniar, and Irwin Tisna Amidyaja. “Perhitungan Cadangan Dan Desain Pit Pada PT. Kaltim Prima Coal Sangatta, Kabupaten Kutai Timur Kalimantan Timur”. ReTII (November 26, 2018). Accessed May 5, 2024. //journal.itny.ac.id/index.php/ReTII/article/view/891.