North China's Inner Mongolia Autonomous Region will increase its coal-producing capacity to 1 billion tonnes in 2015, one-fourth of the country's total, local authorities said Saturday.

The region saw its annual coal output soaring from 114.5 million tonnes in 2002 to 637 million tonnes in 2009, replacing Shanxi Povince as China's biggest coal producer.

Inner Mongolia will keep its coal output at around 700 million tonnes this year, and will shut down all small mines with annual output of less than 300,000 tonnes, the region's coal industry bureau said.

It will also reduce the number of coal companies from 350 at present to 180 and form two mining giants with annual output of 100 million tonnes through mergers and aquisitions, the bureau said.

The region, which has the country's largest proven coal reserve of 732.3 billion tonnes, will also invest more on the coal chemical industry to boost value added.