A drumming sound reverberates across the bridge and over the valley: the gold panners are hard at work.

Dotted along the edges of a river bed are hundreds of people, rhythmically banging wooden poles into the red earth. They are gold miners “sampling” the dry soil for the precious metal. Crouched alongside them are other workers, carefully panning piles of earth through homemade metal sieves.

Maria, 45, holds out a plastic dish of earth. “See? Here it is.” She points to some tiny fragments of what looks like glitter. “Now we know there is gold in this spot, so now my husband will continue to dig deeper to see if we can find more. Maybe we will or maybe we won’t. With this work there is no guarantee.”

Maria’s 10-year-old son, Raoul, lies in the shade offered by a sapling clinging to the rock. She says she had to take him out of school after he developed epilepsy. “There is no one to look after him at home so he has to come here. It isn’t good for him to be in the sun all day but what can I do? If he has a seizure, he needs me with him.”

Raoul is not expected to work. But several other children are engaged in the same back-breaking labour as their parents.

Younis, a father of two boys, aged nine and 13, who are driving poles into the ground next to him, explains: “This work is hard and we know it is not suitable for children. But what can we do?

“Children here only go to school if the parents have the financial means, but most of us do not have the means. We only get paid when we find gold. Last week we sold a gramme and earned 70,000 ariar [about $20] but that was shared between four of us.”

The majority of Madagascan gold is mined this way. There are an estimated 15,000 gold panners in the country, producing 3-4 tonnes of gold annually. These artisanal miners only became a recognised part of the industry in 2006 after the introduction of a new mining code designed to improve standards.

Under the legislation, the miners have to buy an annual permit for just under $2, while the dealers collecting the gold pay about $50 a year; money that is supposed to go directly to the local mayor’s office to pay for essential services like roads and clinics.

However, many miners say they cannot afford permits and risk working without them. Others are paid by locals to mine for them on minuscule wages, something not allowed under the code but, according to the miners, still happens often. As Younis explains: “You earn less if you work for someone else but at least the money is paid regularly.”

Demand for gold rose by 21% in the first quarter of this year, reaching a three-year high in June. But precious little of the wealth has trickled down to these families.

Maria Palas co-owns a jewellery house in Madagascar, exporting to China, India and Europe. Her husband’s grandfather, Modi, opened the store in 1922. She says her family have long lobbied the government to improve safety for workers.

“We know the miners are very poor and that this work is too dangerous the way they do it,” she says. “Sometimes they dig too deep, the ground collapses and they die. If we had big companies, foreign investors, running the mines they would be forced to improve standards.”

“Today we pay 90,000 ariary per gramme [$30]. Ten years ago we paid $3 a gramme. We pay more but where are the improvements in the industry?

“But I know there are places in this country where they don’t want mining to be controlled. Private firms there collect the gold, they might take 50 kilos just in one day, all of it is exported illegally, without tax or customs. This is the real reason our industry is so behind.”

Lack of foreign investment was made worse by a political coup that caused major aid agencies to leave Madagascar in 2009. The aid industry only returned in 2012. Most foreign investors have yet to follow, mistrustful of continued political strife and the widespread corruption – Madagascar ranks 123rd in Transparency International’s corruption perceptions index.

The German aid agency Giz is working with small-scale miners to promote safer and more environmentally friendly methods of extraction. Country director Alan Walsch says: “The sector is very disorganised and informal. That and the political instability makes it very difficult for investors.

“But I am sure responsible investment would certainly help, both in terms of exploiting resources more safely and environmentally friendly as well as preventing illegal exports. We are seeing increasing conflicts over resources between local miners. Our focus is on protecting the local environment and on strengthening the skills and capabilities of these small-scale prospectors.”

In the Palas workshop several elderly artisans work the gold into rings, bracelets and necklaces using traditional methods.

Maria Palas explains: “The fathers of the men you see here worked with my husband’s grandfather. We don’t need to teach them because the skills are passed down through generations. It can take a lifetime to become skilled. We pay our workers very well. But I always say we don’t pay for the work. We pay for the trust.” At that she laughs.

“We have so many minerals and gems here in Madagascar. But without trust we don’t have anything.”