Illegal gold mining is fueling ‘mercury boom’ in Mexico, poisoning people and environment

San Joaquin: A drill echoes through narrow tunnels deep within the mountain where miner Hugo Flores bores into rock in search of one of Earth’s most toxic elements.

Buried in red stripes of minerals illuminated by his headlamp is mercury.

Here in the pine-covered mountains known as the Sierra Gorda – one of the most biodiverse stretches of Mexico – a “mercury boom” is underway.

Soaring international gold prices are driving up the price of mercury, a toxic metal key in illegal gold mining, to all-time highs. While the demand triggers a mining rush in central Mexico, sustaining thousands of miners and their families, it also exposes them and the fragile environment to mercury poisoning. At the same time, this Mexican mercury is fueling illegal gold mining in the Amazon, contaminating large areas and harming both people and the environment.

Global efforts to ban mercury mining have only made mercury from these centuries-old artisanal mines even more sought after.

“It’s a way of life here,” Flores said.

In towns like San Joaquin in the north-central state of Queretaro, the price of mercury has skyrocketed more than tenfold over the past 15 years, jumping from USD 20 per kilogram (2.2 pounds) in 2011 to between USD 240 and USD 350.

“For the first time in their lives, mercury is worth something, and the miners are saying: It’s worth poisoning myself if I’m going to earn something,’” said Fernando Diaz-Barriga, a medical researcher who has long studied mercury mines in central Mexico.

Miners follow veins of cinnabar – the ore holding mercury – like ants through narrow tunnels zig-zagging deep below the mountain. They carve into the rock and lug bags of stones strapped to their backs to the surface.

The rock is shovelled into wood-fired brick ovens where the mercury heats into a gas and separates from other minerals. The gas then cools into droplets of silver liquid that slowly drip down a pipe to be collected in small plastic Coca-Cola bottles, each of which sells for around USD 1,800. It takes a ton of rock to produce a kilo of mercury.

Mexico is the world’s second-largest mercury producer after China, yielding 200 tons a year, according to estimates by the United Nations.

Buyers come from around the world to scoop up mercury for cheap from artisanal miners.

“They come and buy mercury for 500 pesos, and then sell it in Peru for 5,000,” said Carlos Martínez, a leader of one of San Joaquin’s mines. “The coyotes, as we call them, they’re the ones that make money at the expense of others.”

Mercury mining in towns dotting Mexico’s Sierra Gorda region dates back centuries. The metal was used in everything from thermometers to cosmetics and legally shipped to South America up until a few years ago, when many countries around the world banned its use. Today, the vast majority of Mexican mercury is trafficked to Colombia, Bolivia and Peru and distributed throughout the Amazon basin.

In the Amazon, the metal is used to extract gold from river soil in illegal gold mining operations increasingly controlled by criminal groups.

The mining has tainted the rivers that bring life to the region.

In July, Peruvian authorities seized a record-breaking shipment of four tons – worth about half a million dollars – of mercury hidden inside bags of gravel headed from Mexico to Bolivia.