Australian mining company Macarthur Coal Ltd. over the weekend said no to an unsolicited $5.2 billion bid from a pair of industrial giants.The bid, a 40 percent premium over Macarthur\'s recent stock market value, was the second time in as many years that Peabody Energy Corp. of St. Louis attempted to buy the coal-mining company. This year, however, Peabody strengthened its bid with support from steelmaker ArcelorMittal, the St. Louis Post-Dispatch reported Monday.Peabody is attempting to expand its presence in Australia, which has plenty of coal and is close to emerging Asian markets, the newspaper said.