On May 20, Caterpillar Inc. received U.S. Justice Dept. clearance to press ahead with its $8.6-billion buyout of Oak Creek, Wis.-based Bucyrus International Inc. The deal, announced in November, is set to close in mid-2011. Caterpillar won’t issue $2 billion in equity to underwrite the purchase, as once planned. Rather, the Peoria, Ill., construction equipment maker is paying for Bucyrus through a combination of cash on hand and debt in the form of a $4.5-billion, five-part bond sale. The purchase is Caterpillar’s largest acquisition to date.