Ghana is Africa's second largest gold producer. International companies have been investing heavily in new reserves, bringing both economic benefits and environmental problems.

Joanna Manu collects drinking water from the Aprepra River in Western Ghana which has twice been contaminated with cyanide from the local Golden Star gold mine.

After the river was polluted, the mining company dug a well for the village. But the water is unfit to drink because of the high concentration of iron.

This photograph was shown to File on 4's Angus Stickler. It shows how the fish died when the river was contaminated by cyanide two years ago. Some of the villagers still ate the fish.

Several hundred kilometres away, a huge open cast mine operated by a North American company employs about 600 people.

Near to the huge commercial mine, a camp has sprung up where gold is being mined illegally.

Workers show File on 4 reporter Angus Stickler the entrance to a 200ft (61m) deep shaft they have dug by hand to mine gold ore illegally.

A pump boy holds a bag of ore he has just hauled up. He is paid $1 (�0.55) a day to collect water that builds up at the bottom of the shaft and receives a share of the mine's profits.

Gold ore from the illegal mines is then ground into powder and washed by hand.

It is then "panned" using mercury and water in a dangerous process. It forms a paste which is then burnt over a charcoal fire giving off poisonous fumes, risking the miners' lives.

This man buys gold paste, turns it into pure gold nuggets and sells it to the government. File on 4 explores the dark side of Ghana's gold mines, 18 July 2006, at 2000 BST on Radio 4.