Buenaventura Chief Executive Roque Benavides listens during an interview at the Reuters Latin America Investment Summit in Lima April 4, 2011. Buenaventura, Peru's largest precious metals miner, estimates its $750 million Chucapaca joint venture with Gold Fields will produce 500,000 ounces of gold per year, Benavides said on Monday. REUTERS/Enrique Castro-Mendivil (PERU - Tags: BUSINESS)