Copper ended Tuesday with its biggest one-day loss in about five weeks, caught in a broad-based commodity rout led by a sharp drop in oil and fears that Japan's nuclear crisis could stall a global recovery. COMEX May copper fell 7.65 cents to settle at $4.3835 per lb, near the lower end of its $4.3610 to $4.4750 session range. COMEX trading volumes grew to a hefty 65,800 lots by 2:01 pm EDT (1801 GMT), nearly two-thirds above the 30-day norm, according to Thomson Reuters preliminary data.