Darkness enveloped a disused mine in South Africa’s eastern Mpumalanga province as a pick-up truck left the site’s entrance and drove off into the night, loaded with coal.

Informal miner Bonginkosi Mhlanga threw a pickaxe over his shoulder and descended back below ground, where he would remain until daybreak.

Locally known as “zama zamas” – “those who try and try” in the Zulu language – Mhlanga and his counterparts scrape a living by chipping away at abandoned mine shafts previously exploited by mining conglomerates.

There are thousands of informal miners in South Africa, according to the National Association of Artisanal Miners (NAAM).

Many were left jobless when mining companies moved on, struggling to find new work in a country of 59 million people where unemployment stood above 30 percent even before the coronavirus pandemic hit.

Mhlanga, 31, skidded down 82 slippery steps bringing him back down into a narrow tunnel just 1.60 metres (5.2 feet) high.

The air grew thick as he made his descent, walls and floor dripping with humidity.

Bent-over figures brushed past, barely visible in the darkness as they lugged bulging sacks of coal up to the surface.

The ceiling lowered as Mhlanga made his way forward, passing patches of fungus until he reached a black vein in the rock some 2 metres (6.5 feet) wide.

“Here is my spot,” he told AFP news agency.

“I take care of it, I keep it clean, and no one is supposed to touch it.”

Using a headlamp, Mhlanga lifted his pickaxe and plunged it repeatedly into the rock with all his strength.

Black fragments flew out and fell at his feet.

He would later gather the raw coal with his bare hands and stuff it into old polypropylene sacks to sell for a meagre 500 rands ($35) per tonne.

Mining is an important source of revenue for South Africa, raking in about 8 percent of gross domestic product (GDP).

“Zama zamas” operate in about 6,000 disused mines across the country, NAAM estimates.

Lack of maintenance and the unmonitored use of explosives can cause ageing tunnels to collapse, burying miners with them.

“When you go down there you never know whether you’ll be back,” Mhlanga said, reluctant to talk about past incidents.

“If it happens, you have to run and leave everything behind.”

Mhlanga dragged his last bags of coal back up the 82 steps. He has made just 250 rands ($17) for a twelve-hour night shift.