Will pollution from the PolyMet mine flow into Lake Superior, to the Boundary Waters Canoe Area Wilderness (above) or both? (The Minnesota Star Tribune)

Minnesota recently moved a step closer to approving a mining project in northern Minnesota that still has a number of sizable questions that demand answers before the Dayton administration or any Minnesotan should feel comfortable.

The Minnesota Department of Natural Resources (DNR) last week declared the most recent draft of the environmental-impact statement (EIS) for the proposed PolyMet mine in northern Minnesota to be adequate.

The supposedly adequate EIS contains a number of major gaps that should concern the average Minnesotan. Many of the key points that were supposed to be addressed in this document were left unresolved or simply punted to the permitting process. What this means is that major decisions will now be made in a far-less-transparent manner than if had they occurred as intended as a part of the EIS review.

After the investment of over a decade and millions of dollars on the PolyMet EIS to convince the people of Minnesota that the project can be done in a way that will not jeopardize the environment or the state's finances, it still leaves critical questions unanswered.

1) Will the state of Minnesota follow its own rules that prohibit mines requiring long-term treatment of polluted water after closure?

Minnesota's rules for copper-nickel mines were designed to prevent long-term pollution by requiring that mines be "maintenance-free" at closure. PolyMet's own models suggest that it could take centuries after the final ore is extracted for the site to become maintenance-free. Will the state enforce the law? Or will regulators help PolyMet skirt the law by allowing the mine to stay technically "open" for centuries after mining has stopped?

2) Will the state require an upfront damage deposit sufficient to protect taxpayers and the environment?

The single largest risk this mine presents to most Minnesotans is the financial cost of cleaning up the site once the mining company leaves or cleaning up a pollution spill the likes of which we have recently seen in Colorado and British Columbia.

The state requires the company to put up a damage deposit to help prevent these costs from falling on the taxpayers. But the mining company has been adamant that the amount it be asked to put forth can be determined at a later date. Will the people of Minnesota be at risk for paying for cleanup costs? This is another question the EIS does not answer.

3) Will pollution flow north to the Boundary Waters Canoe Area Wilderness, south to Lake Superior or both?

For years, PolyMet has claimed that polluted water escaping the site would flow only south, toward Lake Superior. Independent review of the project suggests it is likely pollution would also flow north into the Boundary Waters. The U.S. Environmental Protection Agency has said the state must take time to gather the data required to answer this question. Whether the Boundary Waters is at risk seems like a pretty basic question. This is another question the EIS does not answer.

4) Will regulators require PolyMet to show how it'll compensate for thousands of acres of lost wetlands?

PolyMet's proposal, if permitted, would be the largest single destruction of wetlands in modern Minnesota history. It would dig up over 900 acres of high-value wetlands; the company has identified a plan to replace or restore equivalent wetlands. However, PolyMet may drain the water from up to 8,000 additional acres of wetlands. PolyMet is required by law to replace these wetlands, too, but has not come up with a plan for how it would do so. Will PolyMet compensate the state for thousands of acres of lost wetlands? This is another question the EIS does not answer.

While the industry will no doubt herald the adequacy of the EIS as a milestone in the approval process, it is clear that many key questions remain and that the decision on whether to permit this industry with a troubling history of pollution is far from made. Now that the DNR has decided to let PolyMet punt on important details in its proposal, it's up to Gov. Mark Dayton to make sure the state doesn't fumble by ensuring that he gets real answers before he makes the ultimate decision.

Scott Strand is executive director of the Minnesota Center For Environmental Advocacy, Paul Danicic is executive director of the Friends of the Boundary Waters Wilderness and Paul Austin is executive director of Conservation Minnesota.