Rustenburg, South Africa – On August 13, a wall of soil collapsed and killed 14 miners, most of whom were believed to be undocumented migrants, at a disused mining site near Nkaneng, an informal settlement outside Rustenburg in South Africa’s mineral-rich North West province.

“It happened in a flash, and the earth swallowed a dozen,” Lerothodi Nale*, a migrant from Lesotho who escaped the collapse and ran to alert nearby security guards, told Al Jazeera.

Without a passport, Nale left the scene afterwards, fearing arrest. More miners could still be trapped underground, North West police commissioner Lieutenant-General Arthur Adams told journalists, including Al Jazeera.

The disaster has exposed a darker side of South Africa’s chrome wealth: an underground economy where vulnerable migrants, unemployed former mineworker and criminal groups converge around a lucrative mineral trade.

Deadly riches

Rustenburg sits above the Bushveld Igneous Complex, one of the world’s richest geological formations, containing vast deposits of platinum-group metals and chrome. The region’s minerals have long powered industries including stainless steel production and advanced industrial applications.

South Africa is the world’s largest chrome producer and exporter, with much of its ore feeding global supply chains, particularly China’s stainless steel industry.

But alongside the formal mining sector, illegal extraction has expanded in parts of the country, including North West province, where authorities have raised concerns about unauthorised mining operations, environmental destruction and criminal groups exploiting abandoned and inactive mine sites.

For migrants like Nale, these abandoned pits offer both opportunity and danger.

“The disused mines are sitting graves with no geologists to confirm if rocks are still stable down there,” said metals governance expert Tapuwa Nhachi.

South Africa’s government has announced programmes to rehabilitate abandoned mines and close dangerous shafts, but critics say the scale of the response remains far below the challenge facing the country. Thousands of abandoned mine shafts remain across South Africa, creating opportunities for illegal operators and exposing workers to deadly conditions.

“Not a month goes without fatalities in abandoned mine holes,” Nhachi told Al Jazeera.

Chrome is attractive to illegal operators because deposits can often be reached closer to the surface, lowering extraction costs compared with deeper underground mining.

“For criminal networks, it becomes easier to extract, process and move the ore into supply chains,” environmental remediation expert Shamiso Mupara told Al Jazeera.

The result is an economy where profits are concentrated among those controlling equipment, transport routes and access to buyers, while miners take the greatest risks.

The underground pipeline

Nale describes a system that begins far beyond South Africa’s borders.

Undocumented migrants from Lesotho, Zimbabwe and Mozambique, alongside unemployed South Africans including former mineworker, are recruited by intermediaries who provide transport money and promise work around Rustenburg’s chrome fields.

On arrival, Nale said, workers are divided into groups controlled by criminal networks that provide food, mining equipment and, he alleges, explosives before sending them underground.

“At this juncture, we are held hostage by the alleged Maresha cartel, which, he says, takes 70 percent of our earnings and forces us to work in unsafe mines until we repay debts,” he said.

Nale alleges that miners can be transferred between groups and forced to continue working underground until additional ore is extracted.

The existence and scale of individual criminal groups involved in illegal mining are difficult to independently verify, but South African authorities have repeatedly linked illegal mining to organised crime, including violence, weapons trafficking and illicit financial networks.

Loren Landau, a migration expert at the University of the Witwatersrand in Johannesburg, said the combination of poverty, unemployment and weak enforcement has created a steady supply of vulnerable workers.

“The pipeline sending scores of young male migrants to subterranean death does not pause because there are few viable job options left,” he told Al Jazeera.

“As soon as this batch of miners dies or gets injured, more destitute men are on the bus to replace them.”

A regional poverty trap

At the gates of Marikana police station, which serves Nkaneng, Dineo Motho, 29, waited for news about her husband, Kgadi Ntuli, 35, who remained missing after the collapse.

Wrapped in a traditional Lesotho blanket against the winter cold, she had travelled about 400 kilometres (250 miles) overnight to South Africa after hearing about the disaster.

“He left home in January to try his luck in Rustenburg chrome pits because with drying lands in Lesotho, there was no water to nourish our goats, crops or fruits. There were no jobs, no food,” she told Al Jazeera.

Ntuli had been travelling between Lesotho and South Africa’s chrome fields, she said, earning enough money to support the family.

Her greatest hope was that he was among those who survived the collapse, but fled afterwards to avoid arrest.

For families like hers, survival itself can mean disappearing from authorities.

Economic hardship and worsening environmental pressures in parts of Southern African have increased vulnerability, pushing some people towards dangerous informal work.

The consequences are increasingly visible in communities surrounding South Africa’s mining zones.

Mmanotshe Ramokoka, traditional leader of the Baphalane Traditional Council in North West province, said illegal mining has damaged farmland, threatened water supplies and created conflict between communities and criminal groups.

“It’s an ecological warzone,” he told Al Jazeera.

He said illegal processing sites have appeared near farming areas, with open pits endangering livestock and waste affecting local environments.

“The gangs have millions to rent industrial equipment for stripping soil for chrome. Migrant diggers die for a tiny fraction of the profit,” Ramokoka said.

The battle moves underground

For years, illegal mining in South Africa was associated mainly with abandoned gold mines around Gauteng province, where informal miners known as zama zamas operated in old underground shafts.

But some experts and community leaders say pressure from the government’s Operation Vala Umgodi (“seal the mine holes” in isiZulu), launched in 2023 to target illegal mining, has encouraged some criminal operators to adapt and seek opportunities elsewhere. Authorities have described the operation as a nationwide effort to combat illegal mining and associated criminal activity.

Some miners now appear to be moving towards less-monitored chrome-producing areas in North West province.

The police have rejected allegations of widespread complicity and say they are taking action against illegal mining networks.

In a statement to media outlets including Al Jazeera, Lieutenant-Colonel Tinyiko Mathebula of the Hawks, the South African Police Service’s specialised organised crime unit, said 23 illegal mining cases had been registered in the Rustenburg area over the past two years, with 63 accused charged.

He added that police had seized 20 trucks and 15 excavators linked to illegal mining activities.

But enforcement alone may not end the cycle.

As long as poverty pushes workers towards dangerous pits and criminal groups control access to chrome wealth, the cycle is likely to continue.

“Nothing scares the hungry,” Landau said.

*Nale changed his surname to speak freely and avoid possible arrest.