People now have more time to weigh in on a controversial federal proposal to halt mining in part of Superior National Forest for two decades.

Citing “immense public interest” in the complex environmental analysis, the U.S. Forest Service and Bureau of Land Management are extending the public comment period by 120 days to Aug. 17.

The U.S. Forest Service has received more than 30,000 comments via e-mail and traditional mail on the matter since January, a spokeswoman said.

The agencies are planning an extra public meeting on the Iron Range, but the time and location haven’t yet been announced. That meeting will be in addition to a March 16 meeting at the Duluth Entertainment and Convention Center that starts at 5 p.m.

The proposal to withdraw part of Superior National Forest from future mining leases was part of a two-pronged announcement the agencies made in December. First they said they would not renew two mineral leases held by Chilean-owned Twin Metals Minnesota because the $2.8 billion underground copper mine it wants to build near Ely risks contaminating the Boundary Waters Canoe Area Wilderness (BWCA). That matter is in court.

Second, they launched an unusual two-year national environmental review to decide whether to place a watershed of the BWCA off limits to minerals exploration for 20 years.

The mineral withdrawal would affect 234,000 acres of Superior National Forest land in the Rainy River watershed, an area that holds huge copper deposits but that also drains into Minnesota’s beloved watery wilderness.

The dual plans hit directly at an environmental dilemma fraught with emotion in northeastern Minnesota. Environmentalists hail the restrictions as a victory while others view them as an attack on economic development in a region desperate for good-paying jobs. A growing list of Iron Range municipalities and organizations opposes the withdrawal.

Last month, a group of Iron Range residents including St. Louis County Commissioner Tom Rukavina and an Ely nonprofit called Up North Jobs sued Gov. Mark Dayton and the state of Minnesota. They are contesting Dayton’s actions last year directing the state Department of Natural Resources to deny Twin Metals access to state land for its copper-nickel mine.

The lawsuit, filed in St. Louis County, argues that Dayton’s actions violated state law and the U.S. Constitution. Dayton told the Star Tribune via e-mail Monday that he was “acting within the scope of my authority as the chief executive of the State of Minnesota.”

Written comments on withdrawing the 234,000 acres of Superior National Forest from future mining leases for 20 years can mailed to Superior National Forest, ATT: Minerals Withdrawals, 8901 Grand Ave. Place, Duluth, MN 55808; e-mailed to comments-eastern-superior@fs.fed.us, or faxed to 218-626-4398.