The 2% devaluation of the renminbi (yuan), announced early Tuesday morning by the People’s Bank of China, is playing havoc with commodity prices and, as we might expect, commodity producers. Prices for West Texas Intermediate and Brent crude oil are down, with copper, aluminum and other base metals trailing downward as well. Only gold and palladium traded higher Tuesday morning.

The yuan’s devaluation raises the price of dollar-denominated commodities for Chinese manufacturers. Ultimately, of course, that price hike is made up with lower prices for exported goods, but the commodity metals producers get hammered.

Aluminum traded down nearly 2%, copper prices traded down about 2.5% and nickel traded down more than 3.5%. Ahead of the opening bell, Alcoa Inc. (NYSE: AA) traded down 3.0%, Century Aluminum Co. (NASDAQ: CENX) traded down 6.5%, BHP Billiton Ltd. (NYSE: BHP) traded down about 4.0% and Freeport-McMoran Inc. (NYSE: FCX) traded about 4.6% lower. Southern Copper Corp. (NYSE: SCCO) was inactive in the premarket.

Until the devaluation it appeared that the government wanted to encourage the domestic economy by increasing domestic demand. But a sharp drop in July exports apparently convinced the government that it had to do something to prop up the low-end manufacturing sector and boost exports.

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Hardest hit of the mining stocks is Freeport-McMoRan, down more than 12% in morning trading. The gold and copper miner has been getting beaten up so badly since the beginning of the year that a $1 billion stock dilution announced Monday was good news, lifting the stock about 9%. That surge disappeared in a heartbeat Tuesday morning. Freeport’s shares are down about 40% for the past 12 months and more than 54% year to date.

Alcoa and Century have been battling a glut of aluminum, and the prospect of weaker demand from China simply intensifies the impact of surging supply. Alcoa’s stock is down 40% over the past 12 months and about 39% year to date. Century’s stock is down 68% for the past 12 months and about 77% year to date. In early trading Tuesday, Alcoa traded down more than 5%, and Century traded down more than 9% before recovering somewhat.

BHP and other iron ore miners have seen commodity prices tumble as demand for steel, especially from China, has fallen sharply. BHP’s stock has lost about 48% of its value in the past 12 months and is down nearly 20% year to date. Shares traded down more than 5% Tuesday morning.

Southern Copper’s stock has performed better than any of the others Tuesday morning, down about 11% over the past 12 months and just 2% year to date. The stock traded down almost 5% Tuesday morning.