About 50 people gathered in front of the St. Louis County Courthouse in Duluth Tuesday morning to rally opposition to proposed copper mining in the St. Louis River watershed.

The group also asked the St. Louis County Board to pass a resolution acknowledging that the river faces potential peril from projects such as the proposed PolyMet copper mine near Hoyt Lakes.

In April the group American Rivers named the St. Louis among the 10 "most endangered" rivers in the U.S. because of the potential for water pollution from copper mines.

Andrew Slade, Northeastern Minnesota coordinator for the Minnesota Environmental Partnership, said it makes no sense for the state and federal government to spend tens of millions of dollars, as they are now, to restore the lower St. Louis River from century-old industrial pollution only to allow copper mining to damage the river in the future.

"Let's not clean it up only to pollute it again," Slade said at the county board meeting.

County commissioners took no action on the request, and in fact it's unlikely they would support the group's resolution. The county board is on record in favor of copper mining, which supporters say will help diversify the region's economy.