The commodities tax came into effect on May 6 and applies to all bauxite exports as well as a number of other commodities.

China is the largest importer of Indonesian bauxite. Most of the bauxite goes into Shandong province, where a handful of alumina refining companies process the material, mostly for their own downstream smelters.

Analysts said the tax was good for the Indonesian government but not for miners. It will affect miners’ revenue and significantly affect profit margins.

The new rule, moved to this year from 2014, bans shipments of unprocessed gold, silver, platinum, copper, lead, nickel, zinc, iron ore and sand iron, manganese, chromium, molybdenum, bauxite and antimony in a bid to boost value added products.