An entrained-bed slagging gasifier of 3 ton/day-class was constructed in 1995 and has operated in Korea ever since. A total of nine imported coals were tested to distinguish the gasification performance with coal characteristics under high pressure conditions. Through the tests, Indonesian Baiduri coal was selected as one of the most suitable coals for the gasifier due to its high reactivity, suitable ash fusion temperature, and low ash content. For the Baiduri coal, the gasifier yields more than 98% carbon conversion efficiency and above 80% cold gas efficiency while producing about 60% CO and 30% H2 in the nitrogen-free basis. Results show that none of the heavy metal constituents in the produced slags by the gasification is leached out by water, which is a major advantage over any combustionbased processes where ash normally contains many leachable heavy components that may contaminate the underground water eventually.