Operating under a volatile energy and metals commodities environment has been tough for many mining companies, who are now increasingly being forced to carry out production cuts and other cost savings measures. Adding to the challenges are strict new greenhouse-gas regulations in the works. BHP Billiton ( BBL), for example, withdrew its hostile bid for Rio Tinto last year amid sliding metals prices and the recessionary climate. It has no immediate plans to make another bid, Reuters reports. If BHP plans to reinitiate another takeover attempt, it will have to wait a year before it can make another bid for Rio Tinto at lower prices under UK takeover rules. Rio Tinto shares are changing hands 2.30% lower at $214.95 in mid-afternoon trading as the market reacts to a spate of mixed economic news, including unchanged initial jobless claims and record foreclosures despite more manufacturing activity in Philadelphia. Shares of BHP Billiton slipped 2.20% to $61.49. Some observers say that the general market retreat can also be read as a rush to exercise expiring options or profit-taking before the protracted holiday week. -- Reported by Andrea Tse in New York Follow TheStreet.com on Twitter and become a fan on Facebook.