Here is a paragraph saying what the mining tax is;

Risks To Outlook

Our forecast for growth in Peru may be slightly affected by the government's intention to double mining taxes in the country to between two and six per cent which could be implemented by end-2011. However, we do not expect this proposed levy to significantly affect investment in Peru's mining sector as the proposed tax is moderate compared with mining taxes elsewhere, especially in Australia and Chile. Furthermore, the rewards of Peru's mineral wealth are likely to greatly outweigh this minor deterrent.

here is the link to where this was obtained;

http://www.allbusiness.com/economy-economic-indicators/economic-indicators/15418040-1.html