The [gold] informal rush is indicative of a broader problem with the country’s mining sector – the sense that foreign companies have minted it from their concessions delivering few benefits either to the Ghanaian economy or to the wider population beyond the employment they provide…Governments across Africa are trying to extract more revenue from the mining industry against the backdrop of booming commodity prices and widespread perceptions that the region’s mineral wealth has not translated into broader prosperity…The corporate tax is problematic, however. Ghana granted stabilisation clauses to many of the companies who rushed to the country in the 1990s and thereafter. Any subsequent changes to the terms, would be a breach of contract. AngloGold Ashanti, for example, has said it does not expect to be affected by the new taxes because of the agreement it signed with the Ghanaian state in 2004…
See http://www.business-humanrights.org/Links/Repository/1010152.