Rio Tinto wants approval for revised air permit

Mar 13, 2013

MARQUETTE, MI--   The Michigan Department of Environmental Quality held a hearing Tuesday night on a revised air quality permit for Rio Tinto’s Eagle mine. 

The company says air emission control is no longer needed for its Main Air Raise Vent, the only apparatus that vents air from underground processes.  Rio Tinto says its plant has been reconfigured so that no ore crushing will take place underground.  Officials say sulfide dust and emissions would be so low that emission control wouldn’t be needed. 

Opponents of the change say Rio Tinto’s assumptions are based on models, not experience.  They say there’s no assurance that dust can be controlled with water spray, as Rio Tinto asserts.   

If the DEQ approves the permit it will monitor vent emissions for 120 days from peak operations.  Because of market volatility Rio Tinto has said it’s delaying production until late 2014. 

The DEQ is expected to make a decision within two to three weeks.