Coal seam D belongs to Muara Enim Formation in Central Palembang Subbasin, South Sumatera Basin, which ages of Middle Miocene to Late Miocene. This study aims to determine the quality of the coal, especially sulphur content and form, ash content and composition, and trace elements of heavy metals. Those are important to know as a reference in suitability in the use of this coal. Methods of analysis is proximate, total of sulphur, form of sulphur, SEM-EDS, ash composition, and trace element. The coal is categorized as low rank coal or lignite with a very low total sulphur max 0.25%, dominated by the organic sulphur formed during the peatification and coalification process (syngenetic). The coal has a safe ash composition. It shows from a very low metal oxide content that causes slagging and fouling at low temperatures process. Likewise, the trace element content of the coal such as chromium (Cr), cadmium (Cd), manganese (Mn), lead (Pb), nickel (Ni) is still far below the threshold for trace element content in coal.

Uji coba teknologi UCG telah banyak dilakukan di berbagai negara, baik pada skala laboratorium maupun pilot. Berdasarkan hasil uji coba tersebut, UCG dinilai layak secara teknis dan ekonomis. Keunggulan utama UCG dibandingkan dengan metode penambangan batubara konvensional adalah memanfaatkan potensi batubara dalam, sedikit menghasilkan limbah padat, emisi gas rumah kaca rendah dan investasi yang dibutuhkan tidak terlalu besar (Kapusta & Stańczyk, 2011; Khan dkk., 2015; Liu dkk., 2007). Meskipun demikian, UCG tetap memiliki dampak negatif terhadap lingkungan, yaitu terjadinya pencemaran air tanah dan amblesan. Di antara kedua dampak tersebut, pencemaran air tanah merupakan hal utama yang perlu diperhatikan. Kegiatan operasional UCG menghasilkan sejumlah senyawa berbahaya bagi lingkungan akibat berbagai reaksi oksidasi, reduksi dan pirolisis yang terjadi selama proses gasifikasi. Pencemaran terjadi, apabila senyawa berbahaya tersebut memasuki badan air tanah (Kapusta dkk., 2013).