Two Fort Collins legislators have petitioned the state to strengthen proposed rules governing in situ leach uranium mining — the method Powertech Uranium Corp. plans to use at the Centennial Project northeast of the city —to prevent groundwater contamination, the Coloradoan reports.

In situ leaching is a method of uranium extraction that dissolves uranium ore with a fluid and pumps the solution out of the ground to be processed.

State Rep. Randy Fischer wrote a letter also signed by Rep. John Kefalas and Rep. Liane “Buffie” McFadyen urging state mining officials to ensure mining companies can’t slip through a loophole in new rules being written to govern in situ uranium min-ing statewide.