I believe Eskom are able to buy their coal at very low prices. As I understand it, the power stations in SA run on a very low quality thermal coal.
They basically admit that their thermal coal sales provides some cash flow, but it's the anthracite that's the jewel in the crown.
Notice their Vryheid Herald advert?
http://www.keatonenergy.co.za/im/files/keaton-herald_11apr12.pdf
