A 30-day public comment period on what's officially called the final environmental impact statement (EIS) for PolyMet’s proposed copper-nickel mine in northeastern Minnesota opens Nov. 13 and closes Dec. 14. Opponents of the mine will have a short window for trying to block the first of what could be several copper, nickel and precious metals mines in the area.

The was 10 years in the making and PolyMet could still face additional hurdles including potential court challenges, before it can start digging for ore the Associated Press reported.

Opponents of PolyMet Mining Corp.’s proposed openpit mine in Babbitt and processing plant in Hoyt Lakes fear the project will contaminate waters with acid runoff, sulfates and toxic metals. Supporters say the environmental impact statement, or EIS, shows the project will comply with environmental laws, and that tapping the area’s vast reserves of nonferrous metals would create hundreds of much-needed jobs.

The 3,500-page document already includes changes spurred by the 58,000 public comments submitted on the previous draft.

After the new comment period closes, Department of Natural Resources Commissioner Tom Landwehr expects to decide “about February” whether to certify the final EIS as adequate. The three narrow criteria for that determination are whether it analyzed the topics it was supposed to examine, whether it responded to comments received on the last draft and whether the DNR followed the proper process for preparing the statement.

At a briefing for reporters, Landwehr said he expects to approve it.

“Clearly we would not have put out a document that we didn’t think was adequate. ... Unless we hear some compelling evidence that we have missed the mark on one of those three criteria, it’s going to be a pretty high bar, I think, to determine that it is not adequate.”

Once the DNR issues that declaration and federal agencies sign off on some final matters, PolyMet can start applying for up to 24 permits that may be required, including the key permit to mine. While the DNR commissioner officially makes that decision, Gov. Mark Dayton has said he will have a lot to say about it.

PolyMet CEO Jon Cherry said the company will be ready to submit permit applications quickly.

The permitting process will give critics new chances to raise concerns, including whether PolyMet can provide bankruptcy-proof financial assurances to cover cleanup costs and whether it can operate safely and comply with environmental laws. The final EIS said the waste water will require treatment indefinitely. Dayton plans to seek an outside review of PolyMet’s finances to examine whether the company has the financial wherewithal.

Once PolyMet has permits, Cherry said, it may be able to start doing work allowed under them as soon as late 2016.

The determination of adequacy and permit decisions could be challenged in court, causing more delays.

Cherry said PolyMet has been working to ensure the EIS and permit applications are done right so they can stand up to legal scrutiny.