Underground Coal Gasification in the North Muara Tiga Besar Utara Area, East Merapi District, Lahat Regency, South Sumatera - Basuki Rahmad; Sugeng Raharjo; Ediyanto Ediyanto; Heru Asbi Rahmanda (Prosiding Seminar Nasional Teknik Kimia "Kejuangan", 2019)