Engineering News 11 June 2010.

The increased export of high-quality coal from South Africa, which left the country’s power utility with poorer quality coal, was leading to power generation efficiency losses, but could also cause maintenance issues now and in the long term, Eskom MD of primary energy Dan Marokane warned this week…

http://www.engineeringnews.co.za/article/eskom-competes-with-global-power-generators-for-sa-coal-2010-06-11