Construction began on the biggest coal mine in northwest China's Xinjiang Uygur Autonomous Region on Sunday.

With a total investment of about 2.6 billion yuan (336 million U.S. dollars), construction of the mine will take 42 months to complete.

It is expected to have annual revenue of 1.45 billion yuan (188million U.S. dollars).

Located in Ili in western Xinjiang, the mine will be the first in Xinjiang to have an annual output capacity of 10 million tons.

The colliery is being built and financed by Xinwen Mining Group Corporation, China's eighth largest coal mining group based in east Shandong Province.

Xinjiang is estimated to have coal reserves of 2.19 trillion tons, or 40 percent of the country's total. The region's coal production stood at 43 million tons in 2006.

Before the end of the decade two or three mining bases each with an annual output of 50 million tons along with a number of 10-million-ton mines are expected to be built in Xinjiang.

Xinwen Mining Group also revealed plans to invest in facilities that will be able to process 30 million tons of coal a year for the production of methanol and olefin in Ili, where the estimated coal reserve is about 301 billion tons.