In a relatively short time, the coal industry has developed into one of the largest influences in the seaborne thermal coal markets in Asia.

The coal production trend in more recent years has been towards the low rank sub-bituminous and lignite coals, which provide a significant cheap thermal coal fuel source for power generation.

Sumatra has the largest estimated potential for coal resources in Indonesia, but currently accounts for less than 10% of the annual production.

Low rank coal is not as stable as sub-bituminous and bituminous coal. This makes the exploration and measurement of these deposits require specific techniques to ensure results are representative of the actual low rank coal in the ground.