Edison Peña, an Elvis fan and fanatical runner, was one of 33 miners trapped 700 metres underground for 69 days at the San Jose mine in Chile in 2010.

I was working as part of BBC team producing a documentary about the rescue effort and the families hoping to see their loved ones again. We befriended Edison's girlfriend Angelica Alvarez who introduced us to him by letters she would send to him through a lifeline. Edison was running daily in his heavy work boots and so we sent him a pair of trainers with a small camera inside and asked him to document the horrific conditions below. 

The miner said he believed the mountain was 'holding us prisoner' and that his only hope of survival was to make himself stronger. 'In the early days the mountain was telling us, "You will die and die slowly and there's nothing you can do",' he said. 'Do you know what it is like to cry with terrible hunger? Do you understand the pain?'

These are his photographs.