Explanation:

Assam coal is characterised by low ash, low moisture, high volatile matter  and high sulphur content. Coal is one of the key natural resources of Assam. It is estimated that Assam has about 371 million tonnes of coal reserves. Assam coal have high calorific value, low ash content high percentage of sulphur and low oxygen content. On the basis of chemical composition and physical characteristics, Assam coals are classified as the sub-bituminous type.