A boatload of sandy, gray muck set out from Alaska a week ago, bound for China. Buried inside the detritus were tiny flecks of gold that China National Gold Group Corp. plans to extract.

The shipment is one of many filled with mineral-rich matter that are sailing into Chinese ports and forming a key, but little-noticed, part of efforts to sate the nation's demand for raw materials.

The Alaskan gold won't appear in China's official imports report or in trade data from major commodity exchanges or bullion markets. China's purchases of copper scrap and investments in oil-sands projects in Canada also fly under the radar, publicly disclosed but not widely watched.

Observers say the low-grade ore making its way to China's shores adds to evidence that Chinese demand for raw materials is greater than standard indicators show, and greater than many investors realize.

Investors instead closely track China's consumption of widely sought commodities, like gold bullion, refined copper and crude oil. Signs that its hunger is rising or falling can move those markets, and help define its broader economic growth.

During this year's first half, for instance, China's refined copper imports fell 13.5%, a decline of 239,000 tons from the same period last year-an apparent sign of weaker demand. But China raised imports of copper scrap and concentrate, which needs further processing. The 362,000 tons of added copper was enough to turn China's imports to a net gain, according to Barclays Capital.

David Fuller's view China has the cash and some of us would say, the vision, to stockpile valuable resources which could easily rise in price and may be in scarce supply on occasion.

If the choice is between strategic commodities or Treasury bonds, I know which I would rather have for the long term. (See the Subscriber's Area for an informative article on this subject, featuring metals for frontier technologies.)