Baoshan Iron and Steel Co yesterday said it has signed a three-year deal with Rio Tinto for coking coal supplies.

The Australian mining company will supply coking coal, a key raw material used in steel making, to Baosteel, one of China's largest steel mills, from this year.

The Shanghai-based mill didn't release the contract's volume and value but said the agreement makes it the first long-term Chinese buyer of coal from Rio, which supplies its customers with 13.6 million tons of coal a year, taking up a 5.7 percent share of the global market.

Mysteel analyst Liu Bao said it's now cheaper and more convenient for steel makers along the east coast of China to import from Australia, the world's largest coking coal exporter, than from inland coal-producing provinces such as Shanxi because of tight railway capacity.

Global supplies have been hampered as the extensive floods in December and January in the Australian state of Queensland disrupted coking coal production.