BHP Billiton (BHP) says it produced 48.9M tons of iron ore in the three months through December, up 16% Y/Y, taking production for the first half of its FY 2014 to a record 97.8M tons, up 19% Y/Y.Despite the strong H1, BHP stops short of upgrading full-year guidance on fears that storms could disrupt mining in Australia's Pilbara region.BHP also reports a 6% Y/Y rise in quarterly copper output to 439.9K tons, and a 30% increase in met coal production to 11.5M tons.