A day after accepting a $4.9 billion joint bid with Peabody Energy ( BTU) for Macarthur Coal of Australia, ArcelorMittal ( MT) has now walked away from the deal, according to a press release. As a result, Peabody Energy will take full control of the takeover venture. Peabody shares fell more than 6.7% to below $38.21 in early trading. Its shares have fallen over 40% year to date. It's a change in course from last week when the Indian-steelmaker ArcelorMittal and U.S. coal giant Peabody announced they'd received approval from Macarthur's largest shareholder China's CITIC to take a majority stake in the world's largest miner of the coal used to make steel. After the approval, on Friday the partnership reported it had taken a near 60% stake in Macarthurs shares. After the share purchase, Peabody's chief executive said, "We are pleased to obtain a controlling interest in Macarthur Coal and look forward to advancing the company's operating performance and growth initiatives."