Governance

Ms. Bertone was appointed by the Board as a director in February 2019. She has nearly 20 years of senior management experience in the energy industry in the Americas and most recently held the position of President of Duke Energy International LLC ("Duke Energy"). During her seven years in this role, she was responsible for operations across South and Central America. Prior to her role as President of Duke Energy, Ms. Bertone spent nearly 10 years in increasingly senior management roles with Duke Energy and its subsidiary companies. Ms. Bertone serves on the board of directors of Yamana Gold Inc., where she serves on the audit and risk and opportunities committees, on the board of directors for Peabody Energy Corp., where she serves on the audit and HSSE committees, and on the board of Amcor plc, where she serves on the compensation committee. Ms. Bertone completed her JD at the University of São Paulo, Brazil and received her LLM from Chicago-Kent College of Law in 1995. She also completed a finance program for senior executives at Harvard Business School in 2010. She is a member of the Brazilian Bar Association. In 2013, she received the Alumni of Distinction Award from Chicago-Kent College of Law, and in 2016, she was recognized by the National Safety Council through their annual “CEOs Who Get It” program, as a leader who demonstrates personal commitment to worker safety and health.

Mr. Graff has served as a director since June 2007. He is a retired partner of PricewaterhouseCoopers LLP where he served as the audit leader in the United States for the mining industry, until his retirement on December 31, 2001. Mr. Graff began his career with PricewaterhouseCoopers LLP in 1973. Since his retirement, Mr. Graff has been a consultant to the mining industry and was a member of a Financial Accounting Standards Board task force for establishing accounting and financial reporting guidance in the mining industry. He represents a consortium of international mining companies and has provided recommendations to the International Accounting Standards Board on mining industry issues and to regulators on industry disclosure requirements of securities legislation. Mr. Graff serves on the board of directors of Yamana Gold Inc. and Alacer Gold Corporation. He received his undergraduate degree in Economics from Boston College and his post-graduate degree in Accounting from Northeastern University.

Mr. Rose has served as a director since November 2016.  He is a senior advisor to Blackstone, the world's largest alternative asset manager. From 2007 to 2016, he was a senior managing director with Blackstone, and served as its global head of public affairs. Mr. Rose also spent 20 years with Goldman Sachs, where he was a managing director and held a variety of senior positions in government relations and media relations in Washington DC, New York and Hong Kong.  Mr. Rose currently is vice chairman of Sard Verbinnen, one of the leading strategic communications firms in the United States. From 1983 to 1987 he was chief of staff to Congressman Mike Synar (D-Okla) and a partner with the law firm of Williams and Jensen in Washington DC.   Mr. Rose is a graduate of the George Washington University and the Yale Law School. He serves on the national board of the NAACP, where he also was on the search committee for its current CEO.