SHANGHAI, Jan. 18 -- Indonesia, the world's biggest tin exporter and Asia's largest shipper of power-station coal, may force miners to cut production if they fail to supply the domestic market under a regulation that took effect at the start of this year, Bloomberg reports.

The government will decide by June at the latest the amount companies must aside for the local market next year, according to the regulation, a copy of which was obtained by Bloomberg News. Companies that fail to comply with the export curbs may face an output cut of up to 50% in the following year, according to the ruling by the Energy and Mineral Resources Minister.

The regulation appears to be mainly aimed at power coal producers and seems unlikely to affect tin supplies. Indonesia's annual tin consumption is some 2,300 tpy according to the World Bureau of Metal Statistics, while the tonnage of tin authorised for export in 2009 was 99,287 tonnes. While Indonesian consumption is growing, this is mainly due to downstream investments in solders and chemicals by PT Timah.