The appeal of Department of Environmental Quality permits issued for an Upper Peninsula sulfide mine wrapped up a fourth week on Friday with testimony from David Stone, a mining engineer for the Kennecott Eagle Minerals Company.
In response to questions from National Wildlife Federation attorney Michelle Halley, Stone said that he did not know whether the cement mixture the company plans to use to fill the mine after use would hold up for 200 years.
“That is beyond the horizon we have engineered for,” he said.
A coalition of groups is suing to block state permits for the mine, which they say would damage the environment if carried out as proposed. One often-cited risk is that an incompletely sealed mine will fill with water that will drain toxins into the watershed.
The Lansing City Pulse provides more details on the complex legal arguments over the planned mine.
Wisconsin has banned sulfide mines due to environmental concerns.