ESTIMASI SEBARAN KUALITAS BATUBARA (ASH CONTENT) MENGGUNAKAN METODE INVERS DISTANCE WEIGHTED (IDW) DAN ORDINARY KRIGING (OK) DI PT. KAYAN PUTRA UTAMA COAL SITE SEPARI, KALIMANTAN TIMUR. GEOSAINS KUTAI BASIN, [S. l.], v. 2, n. 1, 2019. DOI: 10.30872/geofisunmul.v2i1.330. Disponível em: https://jurnal.fmipa.unmul.ac.id/index.php/geofis/article/view/330. Acesso em: 6 nov. 2025.