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The Scandal of Coltan

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Tantalite

Tantalite specimen from Madagascar

Rob Lavinsky/Wikimedia (CC-BY-SA-3.0)

Tantalite is a black, heavy mineral not prized by collectors and little known outside high-technology circles. But ever since 2000, short-lived spikes in the price of this "black gold" have sparked environmentally damaging mining rushes in central Africa. These disruptive events have caused concern around the world.

Your Connection to the Black Gold Rush

Americans are far removed from these kinds of events, but mining rushes make up the history of the United States and the whole western hemisphere. The great California gold rush of 1849 is a cherished episode of American history today. But while it created abundant wealth and gave rise to some memorable American personalities, the Gold Rush was a scandalous disaster for the environment. Mercury poisoning, deforestation, disruption of rivers and widespread crime came with the gold. Within a few decades, the reaction to lawless Gold Rush excesses led to the conservation movement and the Progressive political tide.

Mineral rushes no longer disrupt the United States; indeed, America is no longer a great mining nation. So it has surprised consumers to learn that their beloved cell phones were a factor in destroying the rich jungle habitats of central Africa. The culprit was "coltan," an industry slang term for tantalite.

About Tantalite

Tantalite yields the metal tantalum, whose strength, chemistry and electronic properties make it valuable in many high-tech and medical applications. Tantalum makes great capacitors for premium electronics, including cellular telephones and laptop computers. So the enormous worldwide demand for consumer electronics has put a strain on the supply of tantalite ore. Prices have occasionally soared to hundreds of dollars per kilogram.

Tantalite is an oxide mineral, part of the columbite-tantalite series (Fe,Mn)(Ta,Nb)2O6; a variable blend of iron and manganese in one part of the molecule and tantalum and niobium in another. Tantalite is the end-member with more tantalum, and columbite is the end-member with more niobium. It's twice as dense as ordinary minerals.

Tantalite occurs in granite pegmatites, pockets where the deep-seated molten rock crystallized last. Pegmatites contain many rare minerals, and enormous crystals of the common minerals. Old, deeply eroded continental crust is where many pegmatites are found. Western Australia, Canada, Brazil, and sub-Saharan Africa are regions of ancient crust that yield tantalite today.

Coltan versus Gorillas

The industry term columbo-tantalite has been shortened to "coltan" in central Africa. There, the dense tantalite sand forms placer deposits that can be mined with pans and sluices little different from the low-tech devices used by the Forty-Niners. All you have to do is cut down a swath of jungle, dig up the ground, and wash all the dirt in a river. At the end of a day you have a pile of dead trees, a large hole in the ground, a muddy river and one handful of shiny black coltan. When the price of tantalite spikes, you can sell that handful for maybe 20 bucks.

Central Africa is so desperately poor that thousands of men have rushed to the jungle to mine coltan this way. Prostitution, price-gouging and other disruptions went with them; moreover, the various armies in this war-torn region, both official and amateur, have moved in to take over the trade. Miners invade pristine forests, including the national parks. Besides destroying the land, they shoot the local wildlife—gorillas, okapis and other rare species—for food.

In 2001 the friends of gorillas around the world rose in action, publicizing these disturbing events. The United Nations, concerned about the armies as well as the wildlife, stepped in too. And the tantalite industry, embodied in the Tantalum-Niobium International Study Center, called on its members "to take care to obtain their raw materials from lawful sources. Members should refrain from purchasing materials from regions where either human welfare or wildlife are threatened."

This activity undoubtedly helped the situation, but the world economic slump in 2001 did even more. Demand for consumer electronics fell, and with it the price of tantalite. But in 2005 and 2006 and again in 2010, unrest in the northern Katanga district brought coltan back into the news. Meanwhile, cell phones and laptops can be recycled to recover their tantalum.

PS: The speed with which the bad news came from Africa surely helped save the gorillas. Today the United Nations has email and Web-based news networks in the area, the Integrated Regional Information Networks or IRIN. You can easily follow developments in, for example, the Democratic Republic of the Congo in detail when tantalite prices begin to rise again.

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