The Obama administration has extended a temporary halt on new uranium mining near the Grand Canyon as it eyes a possible 20-year ban.

Speaking from the rim of the canyon, U.S. Interior Secretary Ken Salazar said Monday that wisdom, caution, and science are needed when protecting the area.

Salazar noted that more than four-million people visit the Grand Canyon every year, bringing about $3.5 billion to the local economy. He also said millions of people in such major cities as Los Angeles and Phoenix rely on the Colorado River, which flows through the canyon, for clean drinking water.

Salazar said he is extending the temporary halt – set to expire next month – through December. In the meanwhile, he is considering a 20 year ban on new mining on one million acres near the canyon.

Environmentalists are cheering the decision, while mining companies say it will hurt the economy and job creation.

Salazar says current mining projects are not affected by his decision. He calls uranium a vital part of a comprehensive energy strategy, along with oil natural gas, solar and wind power.