The move comes less than two years after the Montreal-based firm decided to add exposure to the steelmaking raw material by grabbing a stake in the fellow Canadian iron ore company.
In a final report, the agency acknowledges that concentrations of some metals at the Animas river following the spill were higher than historical mine drainage.
The 35.26 carat brown diamond was among a number of rough gems found at Merlin mine, including a 14.6 carat brown rock as well as a number of smaller white diamonds.
System uses a new proprietary solvent that is reportedly slightly more efficient than those used conventionally, requiring less energy and smaller equipment.
Agreement paves the way for Encanto to move from a previously announced memorandum of understanding to a commercial marketing and distribution contract with MTTC, one of the world’s top potash buyers.