Board & Management
Calvyn Gardner Co-Chairman and Chief Executive Officer
Before founding Sigma, Calvyn spent over twenty years holding executive positions at junior and major global mining companies. He was co-founder and managing partner of Hardac Investments, a private equity firm focused on investing in junior mining companies in Africa. Hardac’s major co-investors included Lazare Kaplan International in New York (one of DeBeers’ largest customers in the US) and Mvelaphanda Holdings (South Africa’s largest Black Economic Empowerment Group) in Johannesburg. Calvyn was also General Manager of Operations at Highveld Steel and the CEO of Trans Hex Group. He has an MBA from the University of South Africa and a Bachelor of Science Degree in Electrical Engineering from the University of the Witwatersrand.
Ana Cabral Gardner Co-Chairman and Chief Strategy Officer
Ana is a co-founder and Managing Partner at A10 Investimentos, in addition to having an executive and board position at Sigma. She has over twenty-four years of experience as a senior banker at global investment banks in New York, London and São Paulo. Ana is a former Head of Latin America Capital Markets at Goldman Sachs in New York and a former Managing Director at the firm. She has been involved in a large number of transactions over her career, totalling more than US$100 billion, five of which won the prestigious IFR “Deal of the Year” award, including the privatization of Vale in 1996 and the acquisition of Inco by Vale in 2006. Ana has an MBA degree from Columbia Business School and a Master in Finance degree from London Business School. She serves on the Advisory Board of Columbia University Global Centres and is a board member of The American School of São Paulo.
Marcelo Paiva Corporate Director and Director of Corporate Finance & Investor Relations
Marcelo is a co-founder and Managing Partner at A10 Investimentos. He has over twenty years of experience in asset management and investment banking at leading institutions in New York, London and Sao Paulo. Before founding A10 Investimentos, Marcelo was Portfolio Manager at the Mittal Family Office in Sao Paulo, working with private equity, equity and fixed income investments; and Vice President at the UK asset manager Millennium Global in London, also in the management of private equity, equity and fixed income investments, but for the various portfolios managed by the firm, with combined assets under management of over US$15 billion. Prior to that, Marcelo worked in the investment banking divisions of Credit Suisse in London and of UBS in New York, gaining M&A experience in Europe and in the Americas. Marcelo has a Master’s in Business Administration degree from INSEAD, in France, BA in Economics at the Federal University of Rio de Janeiro, and is a CFA Charterholder.
Anna Hartley Corporate Director
Anna is a Managing Partner at A10 Investimentos, in addition to having an executive and board position at Sigma. She has been involved in mining for over 20 years, while working in asset management and equity research at top tier financial institutions in London and New York. Anna worked for seven years at Beagle Partners, a UK-based equity-oriented hedge fund manager focused on Emerging Markets, Junior Mining and Cleantech. Before that she was for six years with Goldman Sachs in New York working as senior equity research analyst covering Natural Resources, including Metals & Mining and Paper & Forest Products. Anna also worked as senior equity research analyst at Barclays and Bear Stearns, both in London, with a coverage focus on Natural Resources. Anna has a Master’s in Business Administration degree from London Business School in the category Sloan Masters in Leadership and Strategy.
Frederico Marques Corporate Director (Independent)
Frederico is a Brazilian lawyer and the head of the Canadian operations of the Brazilian law firm Cescon, Barrieu, Flesch & Barreto Advogados in Toronto. Previously, he was partner and foreign consultant at McCarthy Tétrault LLP, also in Toronto. He has acted as in-house counsel at Vale S/A, Brasil Telecom S/A and Odebrecht S/A. He obtained his LL.B. from the Pontificia Universidade Catolica of Rio de Janeiro in 1996, his LL.M. from the Universidade Federal of Rio de Janeiro in 2000 and his Ph.D. from the Universidade Federal of Rio Grande do Sul in 2004. Frederico is a former chairman of the Brazil-Canada Chamber of Commerce, a member of its executive board and the head of its mining committee.
Gary Litwack Corporate Director (Independent)
Gary is a Canadian lawyer and Counsel at McCarthy Tétrault LLP in Toronto, Canada. He received his LL.B. from the University of Ottawa, his LL.M. from Osgoode Hall Law School in 1992, and was called to the Ontario state bar in 1990. Mr. Litwack is a member of the Canadian Bar Association and the Law Society of Ontario. Gary is also an Adjunct Professor of Advanced Securities Law at Osgoode Hall Law School.
Maria Jose Salum Chief Sustainability Officer
Maria is a prominent environmental & social responsibility professional in Brazil. She has held a number of roles during her 40-year remarkable technical career in public service and in the private sector. In public service, her roles included Director of Sustainable Development in Mining at the Ministry of Mines and Energy and Senior Representative for the Ministry at the National Council for the Environment (CONAMA). She was also the second woman in 60 years to serve as Deputy Minister of Mining and Mineral Transformation at the Ministry of Mines and Energy. Maria has had an active academic career, holding several senior roles at the Federal University of Minas Gerais (UFMG), a centre of excellence for mining and metallurgy research in Brazil, including Head of Department for Mining Engineering. She has a PhD in mineral technology. Since retiring from public service in 2018, Maria has worked as a consultant, advising some of the largest global mining companies on environmental matters in Brazil.
Guilherme Guimaraes Chief Financial Officer
Guilherme has over twenty-eight years of experience in the mining sector in top management positions in private and public companies. Before joining Sigma, he spent seven years as CFO of the Denham Capital Mining Companies in Brazil. He has an Executive MBA from Fundação Dom Cabral, an MBA in Economic Management of Mineral Resources from B.I. International and a Bachelor’s Degree in Accounting and Economics from Pontificia Universidade Católica of Minas Gerais.
Felipe Peres Vice President – Internal Controls & Accounting
Felipe has over twenty-four years of experience working in corporate positions and large multinational companies in the oil, steel, and mining sectors, in a global environment in Brazil and Switzerland. Felipe is a former leader of consolidation and reporting at Vale, where worked for fourteen years and participated in the IFRS adoption of this company. Prior to Vale Felipe worked for Shell and CSN being in both companies in USGAAP reporting key positions. His main areas of expertise are USA and International accounting, finance performance management, internal controls, process design, and systems design and implementation. Felipe graduated in accounting with honors from Universidade Federal do Rio de Janeiro and has specializations in merger and acquisitions from Chicago Booth University and analytics for business from IMD – Switzerland. Felipe serves as an advisor to the board of the Brazil-Switzerland Chamber of Commerce.
Vicente Lobo Chairman of Technical Committee
Vicente Lobo is trained as a mining engineer and has over 30 years of experience in executive roles at major Brazilian natural resource companies, including as COO of Bunge Fertilizantes and COO of Vale Fertilizantes. He also served as Secretary of Geology, Mining and Mineral Transformation at Brazil’s Ministry of Mines and Energy, where he was responsible for the program that included the creation of Brazil’s current mining regulator Agência Nacional de Mineração (ANM) and for updating the national mining code, which was a landmark event for the development of the Brazilian mining industry. He is currently Managing Partner at the mining consultancy firm Lobo Engenharia.
Wes Roberts Co-Chairman of Technical Committee
Wes Roberts, M.Sc., P.Eng., MBA is a professional mining engineer with over 35 years of experience specializing in the economic evaluation and development of mineral deposits. Mr. Roberts is a Director of Empress Royalty, Sparton Resources, Golden Share and Canadian Gold Miner. Over his career, Mr. Roberts has gained extensive experience in mineral exploration, mining operations, Project engineering and management as well as diverse mining engineering experience that includes precious metals, base metals, iron ore and industrial minerals. Mr. Roberts has held numerous positions in the mining industry, which include Canada Talc Limited, Derry Michener Booth & Wahl, Davey International, Bharti Engineering, GMP Securities, Inco Ltd, Breakwater Resources Ltd (VP Corporate Development) and VP Mining to the Canadian law firm Heenan Blaikie LLP. Since then, Mr. Roberts has held positions as Mineral Engineering Consultant with the American law firm Dorsey & Whitney LLP, Mineral Engineer for Gravitas Mining Corp and most recently as Mining Engineer at Principle Capital Partners.. Mr. Roberts holds a B.Sc. (Mining Engineering) and M.Sc. (Mining Engineering) from Queen’s University, and an M.B.A. (Finance) from the Schulich School of Business (York University).