CANBERRA, Australia (AP) _ Australia's government has introduced legislation to impose a 30 percent tax on the burgeoning profits of iron ore and coal mining companies that are feeding Chinese demand.

The legislation introduced to Parliament on Wednesday is not certain to pass since key independent lawmakers have yet to state their support. The tax would replace the current royalty tax on tonnage levied by states.

Prime Minister Julia Gillard's minority government needs the support of at least four of five uncommitted lawmakers for the tax bill to be implemented in July 2012.

Assistant Treasurer Bill Shorten told Parliament that mining companies' profits have risen 262 percent in the past decade.