Environmental groups have threatened to take legal action against the federal Bureau of Land Management (BLM) for authorising Denison Mines to reopen its mine near the Grand Canyon.
The Canadian mining firm said it would reopen its uranium mine located 20 miles north of the canyon by the end of the year, The Associated Press (AP) reports.
The company recently received an air quality permit from the Arizona Department of Environmental Quality for the Arizona 1 site.
Arizona 1, which has been partly developed for underground mining, can now complete remaining work and begin the extraction of 109,50t of uranium ore per annum.
The BLM said that Denison has an authorised mine proposal and should be permitted to restart operations after closing the site 20 years ago, AP reports.
Environmental groups are protesting against BLM's decision stating that it is based on an outdated environmental analysis and has not looked at the impact on endangered species.