Mongolian 'ninja' miners

A huge fake gold nugget decorates the entrance sign for Zaamar district, the home of one of Mongolia’s biggest gold mines Photograph: Jonathan Watts/Freelance

Mongolia's 'wild west' - ger tents, wooden shacks, disco bars, a police barracks and mining offices make up the town of Ogoomor in Zaamar district Photograph: Jonathan Watts/Freelance

A ninja miner grins as he shows the gold he has panned in a single day. This picture was taken in 2004, before the current crackdown on illegal mining Photograph: Jonathan Watts/Freelance

Ninja miners pan for gold near Ogoomor. Their nickname comes from the green plastic bowls they carry everywhere on their backs - they think it makes them look like the characters from the cartoon series Teenage Mutant Ninja Turtles. This picture was taken in 2004, before the current crackdown Photograph: Jonathan Watts/Freelance

A ninja miner works in the shadow of a Russian dredger. This picture was taken in 2004, before the current crackdown Photograph: Jonathan Watts/Freelance

A Russian dredger churns up earth in search of gold near Ogoomor. The ninja miners used to work in its wake, panning for left-over flecks of gold missed by the huge machine Photograph: Jonathan Watts/Freelance

A goat crosses the bridge over the river where ninja miners used to pan for gold. Cashmere wool from goats is one of Mongolia’s primary exports Photograph: Jonathan Watts/Freelance

Soldiers and police inspect a car at a checkpoint on the road into Ogoomor. mining area is protected by the military at the request of Russian mining companies, who were over-run last year by ninja miners Photograph: Jonathan Watts/Freelance

Purevdash, a retired geologist, says his children and grandchildren have been repeatedly detained by police who care more about the Russian mining companies than local people Photograph: Jonathan Watts/Freelance

Ninja residents of Ogomor stand outside a ger tent. They say they are victims of arbitary arrest and beatings by police aimed at driving them out of their homes Photograph: Jonathan Watts/Freelance

A Mongolian policeman enjoys a cigarette. Despite its reputation as the flagship of democracy in central Asia, human rights groups worry that security forces are being used to protect foreign mining interests at the expense of local citizens Photograph: Jonathan Watts/Freelance