Rare rare earths

Rare earths-17 chemical elements in the periodic table-are the "secret" ingredients in products ranging from smart phones to smart bombs. Despite their name, rare earth elements like cerium are as abundant as copper but difficult to separate from their surroundings-and almost always contain radioactive uranium and thorium.

Until recently, China was the only country willing to dirty its hand with the environmentally unfriendly byproducts: Although it only has 30 percent of the world's rare earths, China currently accounts for 93 percent of the world's supplies. That's because China has actively sought control of mines in Africa, where much of the world's rare earths are believed to reside.

But China has tightened its export quotas, even though world demand has outstripped supply since 2009.

Some fear that China someday could halt exports, with dire military and economic consequences. Manufacturers use rare earths in cars, computers, home appliances, audio and video equipment, and computers. The U.S. missile guidance system also relies on rare earths.

Interest is growing among U.S. mining firms and one company, Molycorp, claims to be able to conquer rare earth mining challenges: Its Mountain Pass facility, perched in the California desert yet close to rail and road transit, has the necessary permits to mine rare earths, and the only protected species nearby-the desert tortoise-is rarely seen.

The mine has a stark beauty, with a clear blue desert sky soaring above a blue green groundwater pool at the base of the 300-foot-deep open mining pit. Fifty- and 100-ton dump trucks lumber up and down its haul road. But hints of trouble lurk. Molycorp's stock has been on a wild ride-now just above $3 billion, down from its July 2011 high of over $5 billion-and safety issues loom. A sign greets visitors to the mine: "Number of days since the last Lost Time Accident: 2291."

Ironically, rare earths are essential in the manufacture of hybrid cars, wind turbines, and energy efficient fluorescent lamps, but environmentalists worry about wastewater leaks and other potential toxic effects.

Out of Africa

A set of original diary pages by missionary and explorer David Livingstone, recording his experiences in Congo in 1871 during his final African expedition, has been published for the first time. Livingstone scribbled his raw observations-rewritten in the diary he published later-using berry ink on old newspaper. Today the ink is nearly invisible. Researchers coaxed the faded cursive from obscurity using high-tech scans that measured multiple wavelengths of light.

In a July entry, the Scottish missionary described a massacre of up to 500 Africans by Muslim slave traders: "It is awful-terrible a dreadful world this-as I write shot after shot falls on the fugitives ... Oh let thy kingdom come."

The full text and scans are viewable at livingstone.library.ucla.edu/1871diary. - Daniel James Devine