A unit of mining giant Grupo Mexico SAB is appealing a ruling that it is on the hook for $1.38 billion in cash and a stake in lucrative Peruvian copper operations to Asarco LLC, in a case alleging Grupo fraudulently shifted the shares, tipping Asarco into bankruptcy, Bankruptcy Law360 reported. Asarco first sued Grupo subsidiary Americas Mining Corp. in February 2007, arguing that Grupo Mexico's 2003 transfer of Asarco's 54.2 percent ownership in Southern Copper Corp., formerly Southern Peru Copper Corp., to AMC was fraudulent.