PetroChina has discovered 115.2 billion cubic metres of proven coal seam gas reserves in the Qinshui Basin in northern Shanxi province, the largest in China, the China Petroleum Daily reported on Jan. 30. China's state reserve evaluation agency has endorsed 30.8 bcm new proven deposits in the Zhengzhuang block after earlier approvals of 84.4 bcm of proven deposits in Fanzhuang and Zhengzhuang blocks, the report said. The blocks in Qinshui Basin are being developed by PetroChina's Huabei Oilfield unit, and another PetroChina unit, PetroChina Coal bed Methane Gas Co, which worked in other regions.