A drug gang stole 3 tons of gold in a scam so perfect it’s still going

BURITICÁ, Colombia—Some 700 yards deep in Colombia’s richest gold mine, private security guards crouch behind sandbags, trapped in a failing battle with a drug-trafficking gang that has commandeered 30 miles of tunnels worth hundreds of millions of dollars.

The air below ground is hot, humid, sometimes toxic, and the work is dangerous—defending claustrophobic passageways against tossed explosives and gunfire from AK-47 assault rifles. Two guards were killed and several others wounded last year. On the other side, braving their own dangers, are an estimated 2,000 illegal miners.

The scale of plunder is stunning. Mine owner Zijin Mining Group, a Chinese state-controlled company, estimated that last year it lost more than 3.2 tons of gold, worth around $200 million and equal to 38% of the mine’s total production. The illegal mining, a slow and laborious process that continues largely unpoliced by authorities, is a war “we are losing,” a Zijin security official said.

Rogue miners at Zijin’s mines and elsewhere in Colombia get access, protection and equipment from the Gulf Clan, an armed militia of some 7,000 men that moves cocaine and migrants along routes headed to the U.S. The group seizes Zijin tunnels on behalf of illegal miners in exchange for a cut of the spoils.

Illegal gold mining in South America has expanded in recent years, government officials said, propelled by record-high gold prices, up 30% this year to around $2,600 an ounce. The miners move dredges and excavators into jungles, igniting conflicts with local indigenous groups, and use mercury to separate gold from rock, polluting parts of the Amazon rainforest in several countries.

As history shows, the lure of gold can be irresistible. Some of Colombia’s trespassing miners extract $5,000 or more worth of gold a month, a sum about equal to what business executives earn. Since 2019, about 18 illegal miners have been killed in accidents at the Zijin mine, company officials said.

“The wages are very good, but you risk it all,” said Erik Dubier, a 22-year-old illegal miner. “You can get trapped. There are rock slides. And there’s combat every day.”

Zijin Mining, which operates worldwide, filed a $430 million lawsuit at the World Bank’s International Center for the Settlement of Investment Disputes, alleging Colombia authorities aren’t doing their job. Zijin estimates that illegal miners control more than 60% of its mining tunnels in the mountains around Buriticá, a two-hour drive from Medellín.

The company bought the mine in 2020 from Canada’s Continental Gold for $1 billion, part of Beijing’s global push to secure minerals. Leizhong Li, the company’s chief executive, said violent incursions have since become a daily threat—with little help from the government.

“We tried to talk to the state all last year but didn’t see much will,” Li said. The company estimated that Colombia lost the equivalent of $100 million in taxes and royalties last year.

Daniela Gómez, the vice minister of defense, said Colombia doesn’t have the capacity to flush out the clandestine miners from the “subterranean theater of operations.” The government, she said, wants to avoid violent confrontations that might endanger civilians.

“The demands made by the company are not realistic,” said Gómez. Zijin bought the gold-mine operation “knowing that the illegal extraction of minerals was taking place,” she said.

Over the past four years, illegal miners have built an underground network so vast that Zijin engineers said the mountain has started to resemble Swiss cheese, crisscrossed with makeshift passageways and tunnels leading from an estimated 380 aboveground entryways. The Gulf Clan provides bunks, kitchens, bathrooms and security.

The gang also delivers sex workers, marijuana and other drugs to miners during weeklong stints. “There’s everything there,” Dubier said.

Trench warfare

Illegal miners worm their way into the Zijin mine from a chain of small houses perched on a mountain holding one of Latin America’s largest gold mother lodes.

The miners use explosive charges and rock drills to penetrate bathroom floors and bore through hundreds of yards of stone and clay. Inch by inch, the miners excavate passageways to reach the Zijin tunnels.

Militia fighters force the retreat of Zijin security forces with explosives and gunfire in what a company official described as trench warfare. Zijin said it has no other recourse but to surrender the tunnels, a retreat jeopardizing the future of its gold-mine concession.

“It happens every day,” Li said of the subterranean clashes. The company estimated that it has had to abandon an estimated 40 tons of gold deposits in the areas seized by the Gulf Clan and illegal miners.

Gómez, the vice minister of defense, described legal obstacles to searching homes and arresting miners. “I can go to Buriticá tomorrow and capture 300 people,” she said. “The judge will free them by nightfall.”

On a recent tour of the underground tunnels, Zijin’s senior security official at the mine pointed out the wall of sandbags separating company operations from trespassers working less than 100 yards away. The miners’ voices carried through the darkness.

“All the mining from here to there has been lost,” he said, pointing to the distant lights where illegal miners worked. “They advance progressively, taking ownership.”

Miners often seize Zijin tunnels by first tossing explosives and shooting at guards, the security official said. The miners carry jackleg drills and set off as many as 250 detonations a day to break through rock. Their advance has cost Zijin two of the mine’s three sections.

The richest and deepest part of the gold mine remains in company hands. Zijin has about 4,500 workers there and at processing centers. The company excavates around 4,000 tons of rock a day, which yields an average of 53 pounds of gold.

“It’s a tremendous problem,” said Javier Sarmiento, an investigator tracking mine troubles in Buriticá for Colombia’s Inspector General’s Office, a state agency.

‘Lack of control’

Zijin executives said the underground battle worsened after the 2022 election of leftist President Gustavo Petro. Past governments welcomed foreign mining companies, including Zijin. But Petro and his ministers have been critical of large-scale mining, saying they want to shift the economy toward such sustainable industries as avocado farming and tourism.

Colombia’s government says the country needs to transform the economy of Buriticá so that citizens have a choice of better jobs. Officials say they want to open a path for illegal miners to instead form legal cooperatives to run small artisanal mines. Some officials have suggested that Zijin give up some of its mine holdings to trespassers in a bid for peace.

“There are areas in that concession where there is no exploration, no activity whatsoever,” said Luis Álvaro Pardo, president of the state’s National Mining Agency. “So we’re saying, ‘Look Zijin, cede some areas.’”

Previous government had more aggressive policies against armed groups, said Li, the company’s chief executive. In 2016, Colombia launched Operation Crete, which closed more than 250 illegal passageways into the mine over four years.

Zijin said Colombia needed to again close off routes used by criminals stealing company gold. “From our point of view, the policy is not favorable to mining and the multinationals,” Li said. “How can authorities not know this and act against this?”

The state Inspector General’s Office has asked the government to develop a plan of action to stop the theft, Sarmiento said. Nothing has come of the request. “It has a lot to do with politics,” he said. “The arrival of this new government appears to have not been favorable to the situation.”

Brigadier General William Castaño, who oversees a police team assigned to the mine, said his forces regularly confront rogue miners. “There are interventions almost every day,” he said.

Sarmiento and Zijin executives said the state should try to cut off the electricity that powers the drills used by illegal miners. They said police and troops deployed in Buriticá could inspect vehicles traveling on the single road leading to the mine. Vehicles ferry in equipment and supplies and leave laden with stolen gold ore, according to Zijin executives.

“This is a pure lack of control by the authorities,” Sarmiento said.

Thousands of miners have arrived from other parts of Colombia and neighboring Venezuela to seek their fortune. Some have branched away from Zijin’s tunnels to mine gold deposits in La Centena, a mine a few miles away. Those miners deny Zijin’s claim that they are taking company gold.

On a recent day, Andres Rave, an older miner at La Centena, walked through the water and mud of a tunnel floor. He and a handful of others have dug passageways that extend about 200 yards into the mountain.

With the light on his hard hat illuminating colorful, craggy rocks, Rave ran his hand along a distinctive layer of minerals. “This vein that runs here,” he said, ”this is the one that holds the gold.”

Dust particles floated in the air. Rocks underfoot had fallen from tunnel walls and ceilings. Duber Antonio Quiros didn’t give it much thought. He and other miners worked to reinforce man-sized tunnels with wooden beams. Commercial miners use tunnel-boring equipment to build passageways supported by steel and concrete. Some are large enough for trucks.

“We small-time miners don’t have the technology the big companies have,” Quiros said. “But this gets into your blood and becomes your passion.”

Write to Juan Forero at juan.forero@wsj.com