The potential keeps growing for riches at Pebble Mine, a huge minerals deposit in southwest Alaska near Bristol Bay and the world's most productive wild salmon streams.

A new estimate of the resources is larger than the 2008 figure, growing 12 percent for copper, 14 percent for gold and 16 percent for molybdenum, which is used to strengthen steel.

Canadian-based Northern Dynasty Minerals Ltd. is developing the prospect with London-based Anglo American PLC. Northern Dynasty says Pebble contains an estimated 80 billion pounds of copper, more than 100 million ounces of gold and 5.6 billion pounds of molybdenum.

The mining companies hope to have a preliminary development plan done by the end of the year, with permitting to begin in 2011.