Indonesia's coal reserves have increased slightly as of the end of 2019, meaning that if annual production remains at around current levels the reserves will last until 2090, the country's energy ministry said.

Total coal reserves in the country as of the end of 2019 stood at 37.56bn t, up slightly from 37.34bn t at the end of 2018, the ministry said. Total reserves of low-calorific value (CV) coal stood at 14.4bn t at the end of last year, while reserves of mid-CV coal were at 20.3bn t. But reserves of high-CV coal stood at just 2.72bn t.

Coal reserves refer to coal that is currently extractable with current mining infrastructure, as opposed to coal resources, which refer to coal in areas that have yet to be developed.

Out of the 37.56bn t, 20.5bn t is classified as proven mineable reserves, with the remainder classified as estimated reserves. The bulk of the mineable reserves are located in Kalimantan province, with a total volume of 24.7bn t.

These figures are based on reports collected from coal mining companies currently operating in Indonesia, the ministry said, noting that reserves should continue to increase because under the new coal mining law that was ratified in May producers are required to submit details and findings of their exploratory work to renew or transfer their special mining business permits (IUPK).

Indonesia's energy ministry said earlier this year it was drafting regulations to accelerate exploratory work in the mining industry to shore up reserves for future production.

One of the proposed measures aims to improve coal mining companies' exploration activity, requiring them to earmark a certain amount in their annual budgets for resource exploration.