From gold mine to auction house: what Sebastiao Salgado's latest print sale teaches us about making photos that really matter

A grid of ten black-and-white photographs showing the Serra Pelada gold mine in Brazil, ranging from wide aerial views of a vast pit swarming with thousands of workers to close-up portraits of mud-covered men carrying heavy sacks up precarious wooden ladders.

There's an unsettling irony at the heart of the biggest photography auction story of the year. The prints now estimated to fetch between $100,000 and $150,000 at Phillips in New York show men covered in mud, carrying sacks on their backs in a vast open pit mine in Brazil, earning almost nothing. These photographs document misery, back-breaking labour and forgotten lives. Yet now they are among the most coveted objects in the art market.

Welcome to the world of Sebastião Salgado, who spent more than four decades making images the world needed to see, and who passed away in May last year. His estate, and the collectors who believed in him, are now watching his work command prices that reflect just how singular his vision was.