BARACK Obama took a big step towards preserving one of the world's natural wonders on Monday, banning uranium mining on 400,000 hectares (988,421 acres) of land around the Grand Canyon.

The move, announced by the interior secretary, Ken Salazar, at a film screening in Washington, bans new mining claims around the canyon for the next 20 years. The area is rich in uranium deposits.

'A withdrawal is the right approach for this priceless American landscape, Salazar said in his speech.

'People from all over the country and around the world come to visit the GrandCanyon. Numerous American Indian tribes regard this magnificent icon as a sacred place, and millions of people in the Colorado river basin depend on the river.

Environmental groups said the move, which was opposed by the mining industry and some Republicans, would secure the US president's environmental legacy.

The measure does not affect some 3,200 existing mining claims around the canyon, however. The administration said there would be continued development of 11 uranium mines.

Conservation groups said Obama had shown politicalcourage in going ahead with the ban in the face of opposition. 'Despite significant pressure, the president did not settle for a halfway measure,' said Jane Danowitz of the Pew Environment Group.

In the final years of the George Bush presidency, when uranium prices were rising worldwide, mining companies filed thousands of claims in northern Arizona on landsnearthe Grand Canyon.

They also proposed reopening old mines adjacent to the canyon. Salazar ordered a temporary halt to claims in 2009 after Obama came to office. Government officials proposed the 20-year ban inOctober last year, after an environmental review, calling for the preservation of an 'iconic landscape' 'It is appropriate to pause, identify what the predicted level of mining and its impacts on the Grand Canyon would be, and decide what level of risk is acceptable to take with this natural treasure,' Bob Abbey, the director of the US bureau of land management, said at the time.

Republicans, including the former presidential candidate John McCain, condemned the move to withdraw lands from mining claims as an emotional overreaction.

—The Guardian, London