    Sentence 1: Shares of the company , the  second-largest U.S. coal producer  behind Peabody Energy Corp. BTU.N ,  were up more than 3 percent in  afternoon trade .    Sentence 2: Shares of the company ,  the second-largest U.S. coal producer  behind Peabody Energy Corp. ( BTU ) ,  were up more than 3 percent at midday