mining

Environmentalists file 2 more challenges to Minnesota mine

Environmental groups have filed two more lawsuits challenging the Interior Department's decision to reinstate the federal mineral rights leases for the proposed Twin Metals copper-nickel mine in northeastern Minnesota.

Group: Install air monitors to study frack sand

An environmental-quality committee is recommending that air monitors be installed around Winona to measure the effect that the processing and shipping of frack sand has on air quality.