We’d like to shed some light on recent conversations about stream flow data related to the PolyMet project supplemental draft Environmental Impact Statement (SDEIS).

SDEIS modeling uses data from a U.S. Geological Survey station, located on the Partridge River nearly 17 miles from our mine site, to determine the contribution that groundwater makes to the stream flow and if it would be impacted by our operations. It is solid and respectable government data.

The SDEIS modeling, which is based on 10 years of readings from the USGS gauging station, shows that groundwater adds 0.5 cubic feet per second (cfs) of flow to the Partridge River at that point. However, data from a new stream-flow gauging station, located close to the mine site, shows a groundwater contribution of between 1.3 and 1.8 cfs. These new readings are influenced by discharges from a nearby taconite mine, which make them difficult to interpret.

It hasn’t yet been determined if the new stream-flow data affect any of the modeling that has been done; the co-lead agency technical experts for the SDEIS are still assessing this.  However, the new stream-flow data does not appreciably change anything in the SDEIS. Why? Because in a sensitivity analysis, scientists plugged in lower numbers than 0.5 cfs and numbers as high as 2.4 cfs and even at that higher level the model showed no negative impact.

In other words, this new data is not likely to change the assessment of the project relative to the project’s ability to meet water quality standards.

We like how Minnesota Department of Natural Resources Spokesman Chris Niskanen summarizes the situation, as quoted in an MPR article:

“It’s been suggested that this is a fatal flaw in the whole [supplemental draft EIS]. That’s absolutely not true. These are the kinds of discussions that sometimes emerge out of an environmental review process like this that are important to making the final draft EIS a better document, and that’s precisely where we are right now.”

Part of the process

Decisions regarding what new data and inputs to include in models are made by regulators based on comments received and reviewed by their technical experts. It’s all part of the process – a process we fully support and one in which we are fully engaged.

We have confidence in the process as well as in the model.


Thank you for your support in this process. Don’t forget to mark your calendar for the third and final public hearing this Tuesday, January 28 in St. Paul. We look forward to another productive, civil meeting to move Minnesota copper-nickel Mining forward.

Categories:Environment | General

Related Posts:

Comments are closed.