Miners scrape off the topsoil and shovel golden-flecked clay into dirt pits, using acids to extract the rare earths. The acids ultimately wash into streams and rivers, destroying rice paddies and fish farms and tainting water supplies.The quest to locate supplies of these materials around the world often takes prospectors to countries that have no regard for the environmental consequences of mining and illegal mining is rampant.
On a recent rainy afternoon, Zeng Guohui, a 41-year-old laborer, walked to an abandoned mine where he used to shovel ore, and pointed out still-barren expanses of dirt and mud. The mine exhausted the local deposit of heavy rare earths in three years, but a decade after the mine closed, no one has tried to revive the downstream rice fields.
Small mines producing heavy rare earths like dysprosium and terbium still operate on nearby hills. “There are constant protests because it damages the farmland — people are always demanding compensation,” Mr. Zeng said.
“In many places, the mining is abused,” said Wang Caifeng, the top rare-earths industry regulator at the Ministry of Industry and Information Technology in China.
“This has caused great harm to the ecology and environment.”
There are 17 rare-earth elements — some of which, despite the name, are not particularly rare — but two heavy rare earths, dysprosium and terbium, are in especially short supply, mainly because they have emerged as the miracle ingredients of green energy products. Tiny quantities of dysprosium can make magnets in electric motors lighter by 90 percent, while terbium can help cut the electricity usage of lights by 80 percent. Dysprosium prices have climbed nearly sevenfold since 2003, to $53 a pound. Terbium prices quadrupled from 2003 to 2008, peaking at $407 a pound, before slumping in the global economic crisis to $205 a pound.
China mines more than 99 percent of the world’s dysprosium and terbium. Most of China’s production comes from about 200 mines here in northern Guangdong and in neighboring Jiangxi Province.
China is also the world’s dominant producer of lighter rare earth elements, valuable to a wide range of industries. But these are in less short supply, and the mining is more regulated.
The companies that rely on these materials have no way to know how much of the materials come from licensed mines or how much is done at illegal mines that use all manner of acids to leach the rare earth elements from the rocks; and those acids pollute the soil and taint the surrounding water.
The biggest user of rare earth elements in coming years may actually be wind turbines, which are made more efficient using these elements.
So, what are considered green tech on first blush are anything but given that the destructive means under which they are obtained is anything but environmentally responsible. Once the supply chain is included, the green tech is considerably less green.