How mercury poisons gold miners and enters the food chain

On the Indonesian island of Lombok, its potential for harm is multiplied because it is being used in conjunction with cyanide.

"Together mercury and cyanide create double the problem in the environment," says Dr Dewi Krisnayanti, a soil scientist specialising in heavy metals at Lombok's Mataram University.
Cyanide helps to dissolve the mercury, and when the waste is spilled into paddy fields it binds with organic molecules in the environment, becoming methyl mercury. This is far more toxic - in Minamata it was methyl mercury that poisoned thousands of people.
http://www.bbc.co.uk/news/magazine-24127661