US law firm Bernstein Liebhard said the suit would deal with "misleading statements" made by the precious metals producer, which has had 21 fatalities on its operations so far in 2018.
A week choc-a-bloc with billion dollar copper, iron ore and cobalt deals ends with huge drop in prices and sell-off in stocks of mining's biggest names.
It gives the company access to 23,903 hectares of land in the country Great Dyke, which has a potential for 96 million ounces of platinum and palladium.
Researchers at the University of Notre Dame invented a new class of molecules whose shape and size enable them to capture and contain precious metal ions.