In play Walter Energy (NYSE: WLT) jumped higher by more than 7% in pre-market trading to over $80/share after the UK's Independent newspaper reported that Anglo American (LON:AAL) and BHP Billiton (NYSE: BHP) may bid for the company. By mid-afternoon the volatile stock – over the past 12 months shares in Walter Energy have traded as low as $56 and as high as $143 – had settled back to trade up around 2%. Global miners are scrambling for coal assets as metallurgical coal trades at record levels above $330/tonne. Walter Energy, which also produces coal seam gas, would follow BHP's August $12 billion buy of US shale gas company Petrohawk.