ANALISIS HARDGROVE GRIDABILITY INDEX BATUBARA TERHADAP PRODUKTIVITAS ALAT GALI MUAT DI PT KTCNBL KALIMANTAN TENGAH. SNPPM [Internet]. 2022 Dec. 22 [cited 2026 Apr. 13];6:11-5. Available from: https://www.journal.ubb.ac.id/index.php/snppm/article/view/3681