Workers at this mine in Choa Saidanshah in Pakistan's Punjab province dig coal with pick axes, break it up and load it onto donkeys to be transported to the surface.

Employed by private contractors, a team of four workers can dig about a ton of coal a day, for which they earn around six pounds to be split between them.

coal mining donkeys pakistan
Miners pose for a photograph at the coal face inside a mine in Choa Saidanshah, Punjab province, Pakistan Sara Farid / Reuters

The coal mine is in the heart of Punjab, Pakistan's wealthiest and most populous province, but the labourers mostly come from the poorer neighbouring region of Khyber Pakhtunkhwa.

Although Pakistan has introduced legislation to deal with child labour, the problem is deeply entrenched in society. Nearly 60% of Pakistan's working children are in Punjab province. Children often inherit huge, unpayable debts and are forced to work as bonded labourers. Children working in mines can be vulnerable to dangers such as sexual abuse by older miners.

The donkeys make around 20 trips per day carrying sacks weighing about 20kg each. The work is dangerous with the constant risk of cave-ins. The miners say they do what they can to care for the animals, with their limited resources, but the difficult conditions mean the donkeys' life expectancy is 12-13 years (compared with 30 to 50 years in more prosperous countries).