Beijing has already closed 450 solid mines, 53 percent of the city's total, said an official with the Beijing Bureau of Land and Resources.

70 percent of the mines will be closed by the end of 2007 and 90 percent by 2010, said the official.

Beijing has abundant mining resources. About 126 kinds of mining resources have been found in the region including 122 solid substances such as coal and iron.

Mines in Beijing occupy 4,890 hectares of land and have accumulated waste residue of 167.89 million tons.

"That contravenes the government's requirement for an ecological environment for the 2008 Olympics," the official said.

Mines that do not meet environmental protection and safety production standards will be closed if they cannot correct their situation, said the official.

Beijing would continue to combat illegal exploitation of gravel, iron ore and coal resources, the official said.