As a revised environmental analysis of the PolyMet Mining copper-nickel mine in northeast Minnesota reignites the bitter debate over the controversial project, it's important to note that the report isn't the final determination on its fate.

Instead, the analysis is intended to provide the public and officials at various permitting agencies with "objective facts about the significant environmental, social and economic effects" of the project so that the permitting decision on its future — perhaps coming in 2015 — more fully accounts for its potential costs and carefully weighs them against this new-to-Minnesota mining's oft-touted economic benefits for the struggling Arrowhead region.

The 2,169-page report is dense and jargon-filled. But it quickly makes clear the sobering responsibility that permitting agency officials must shoulder as they consider the project's fate — a decision that could have ripple effects for other projects in the planning stages. The area has some of the world's richest deposits of copper, nickel and other metals increasingly in demand for consumer electronics and green-energy technology.

Even as the revised analysis makes a sincere effort to demonstrate that the mine's potential pollution could be controlled, it also reveals the serious nature of the potential environmental impacts. New information suggests that the PolyMet open-pit mine site near Babbitt, Minn., and processing plant site near Hoyt Lakes could need water treatment and monitoring for a jaw-dropping 200 and 500 years or more, respectively, to guard against acid runoff and other pollution.

The officials who eventually make the momentous permitting decisions won't just be making a choice about jobs or environmental quality affecting Minnesotans monitoring this historic debate. Instead, they'll be making a choice for generations to come about the Arrowhead's natural resources, including waterways that eventually flow into Lake Superior.

The Department of Natural Resources and the Pollution Control Agency are the two lead state agencies on the environmental review and permitting process for copper-nickel mining, with the DNR ultimately issuing the mining permit.

Rarely have the commissioners for these state agencies been tasked with decisions that will reverberate so far into the future. That's why the simmering debate over the review's adequacy — state officials have provided an unsatisfying 90 days for public input — ought to go beyond the report and pivot quickly into what's known as "financial assurance." That's the money typically put up in advance to make sure taxpayers don't get stuck with the bill for environmental cleanup and monitoring.

Generally, financial assurance has been spelled out in greater detail during the permitting process that follows environmental review. Information generated by the environmental review is critical in determining how much money is needed. Minnesota also has well-regarded laws to guard against firms discharging cleanup obligations in bankruptcy.

That said, the fact that PolyMet's financial assurance needs to cover not just decades but potentially centuries is a game-changer and a logistical head-scratcher. The same issue exists with nuclear waste, except on an even longer time frame, and the unanswered questions about this have stymied development of new plants.

The newly released environmental review wasn't intended to spell out how financial assurance is handled. An e-mail from the U.S. Environmental Protection Agency to DNR officials essentially said the brief financial assurance estimates in the document, which disturbingly appear to have been provided by a PolyMet consultant, were fine for now, though it also anticipates there will be "further refinements."

This week, DNR officials said the agency is committed to making the permit-to-mine process and financial assurance proposals "public in a timely way during the permitting process" but said it's still working out details for this. The agency also said PolyMet will not set conditions for financial assurance and added that financial assurance proposals will be reviewed with "great rigor," with outside financial and scientific experts brought in.

The complexity of all of these issues begs for legislative review. Lawmakers are divided into pro-jobs and pro-environment camps on copper mining, but they ought to bridge their differences to ensure that the state gets the expertise and information it needs to assess the financial assurance with care.