NYALIGONGO, TANZANIA - Three years ago, 14-year-old Julius left his family near the lakeside city of Mwanza, Tanzania, to try his luck mining gold.

Today, Julius is in no hurry to leave, despite having one of the riskiest jobs on a chaotic mine site — handling mercury each day with his bare hands.

"It's good work. I'm paid well," Julius, who wanted to use only his first name, told the Thomson Reuters Foundation, wearing an orange T-shirt and skinny jeans coated with red dirt.

Julius, now 17, said he has been working with mercury for three years, but no one had ever told him it was dangerous.

There are more than 4 million child laborers in Tanzania aged between 5 and 17, according to a government survey released last year in conjunction with the International Labor Organization. That's roughly a third of the country's children.

More than 3 million are doing hazardous jobs, including at illegal mines like the one near Nyaligongo in northern Tanzania, where they are exposed to mercury, heavy dust and work long shifts without safety gear.

Many unaware of laws

The Tanzanian government is aware of the problem but has struggled to keep children out of small, unlicensed mines. Its laws do not allow children under 14 to work, and hazardous work is not permitted for children over 14. Tanzania has signed all major international conventions on child labor and introduced its own laws to prevent the worst child labor.

But not everyone knows of the child labor laws, including families and local officials.

Government workers tasked with enforcing the laws lack the staff and funds for inspections, let alone prosecutions.

"In Tanzania we have a good law and strategy to eliminate all kinds of child labor, but the problem here is who is going to implement this at the local level," said Gerald Ng'ong'a, executive director of Rafiki Social Development Organization (SDO), an NGO that works on child labor in northern Tanzania.

"Local officials don't have enough information about the law and how to protect children."

Lure of gold

The problem is especially hard to tackle in the informal sector, said Emma Gordon, senior Africa analyst at global risk consultancy Verisk Maplecroft, which ranks Tanzania as the 55th-most "at risk" country in its 2017 Child Labor Index, due to be published Wednesday.

"The government's focus is very much centered around large industrial projects, particularly foreign-owned businesses that would be able to pay fines if violations were discovered," Gordon wrote in an email to the Thomson Reuters Foundation.

FILE - Teenage boys mix mercury and ground gold or FILE - Teenage boys mix mercury and ground gold ore at a processing site in Mbeya Region, Tanzania, in this 2013 photo. FILE - Teenage boys mix mercury and ground gold ore at a processing site in Mbeya Region, Tanzania, in this 2013 photo.

In Lake Victoria's gold belt, where gold has been extracted since the 1890s, licensed and unlicensed small mines operate with major mining firms close by. The scrappy "artisanal" mines provide a crucial source of income to people outside Tanzania's cities, but like the mining site at Nyaligongo, many operate without government licences.

The majority of children working in gold mines are employed by individuals running these unlicensed mines, observers say. They are among the worst exploited of the mines' workers, typically earning the equivalent of about 1 euro ($1) a day.

"Pit owners employ children because they're cheap labor," said Ng'ong'a.

Legal or not, the lure of the mines — and the harsh poverty of the farming communities around them — keep children coming.

Brothers Petromos and Mayalamos, 12 and 16, left their village outside Mwanza because they heard there was good money to be made at this mine.

"The work is difficult," said Mayalamos. "But I can only leave this place once I've earned enough."

Nyaligongo village relies on gold to survive.

On the village's main street, cramped shops sell vegetables, SIM cards and lunch to off-duty miners. Middlemen purchase gold from miners to sell in the closest town, Kahama, where it is resold in bigger cities like Mwanza and Dar es Salaam.

Students leave to work

More than 8,000 people live in Nyaligongo, says Faustine Masasila, the village's secretary and a mine site owner, and more are still arriving.

"There are people here who used to have very miserable lives," Masasila said, walking through the buzzing market. "If you work hard, you are guaranteed prosperity."

FILE - Two 13-year-old boys and one 15-year-old bo FILE - Two 13-year-old boys and one 15-year-old boy pour crushed gold ore over a sisal sack to concentrate the particles of gold at a processing site in Mbeya Reigon, Tanzania, in this 2013 photo. FILE - Two 13-year-old boys and one 15-year-old boy pour crushed gold ore over a sisal sack to concentrate the particles of gold at a processing site in Mbeya Reigon, Tanzania, in this 2013 photo.

At the primary school down the road, teachers are less impressed with mining's promise of a good future.

A poster on the school office wall is a testament to the number of children who leave to work when they are old enough.

This year, in Class 1, there are 236 students aged 6 and 7, while in Class 7 there are only 40 students aged 13 and 14.

"I feel very frustrated when children leave and go to the mines instead of going on to secondary school," said Mabula Kafuku, the education officer for the ward. "They don't even have enough knowledge to mine safely."

Children dropping out of school is a nationwide problem in Tanzania and a major impediment to the government's aspiration to become a middle-income nation by 2025. A recent Human Rights Watch report found that in 2016, more than 5 million children aged between 7 and 17 were out of school across the country.

For government workers tasked with inspecting mines for health, safety and labor violations, enforcing the law at the far-flung informal mines sprinkled around the Lake Victoria region is an onerous task.

Masasila, the village secretary, cannot recall ever seeing inspectors at the mining site near Nyaligongo.

"If you have children working in remote areas, you need a budget to visit. We don't have such things," said Hadija Hersi, a regional labor officer in Mwanza. "That's why you have NGOs stepping in to intervene."

Some success

Several nongovernmental organizations, including Terre des Hommes Netherlands, have been trying to get child workers back in school and help families develop alternate income sources to wean them off their wages.

Since 2014, Terre des Hommes Netherlands, working with Rafiki SDO, has managed to help more than 725 children leave the mines. In Geita, another nearby gold-mining area, U.K.-based Plan International has helped 12,000 children withdraw from small-scale mining work and is trying to reach another 11,600.

But as long as people are struggling to find work outside Tanzania's cities, there is only so much NGOs can do.

At the mine, Nyanjige Mwendesha looks on as her three children, ages 10, 12, and 15, sit on the red, dusty ground, smashing up rocks with small metal hammers in the midday sun.

Mwendesha brought her family to work here after there wasn't enough rain on her farm this year. The family needed the money.

"When it starts to rain, I'll go back to the farm," she said.