Alexander is an Indonesian citizen and currently holds the position of President Director, and Chief Executive Officer at PT Amman Mineral Internasional Tbk (AMMAN). As one of the co-founders of AMMAN, he played a vital role in the company’s acquisition of PT Newmont Nusa Tenggara (now known as PT Amman Mineral Nusa Tenggara) in 2016 and led the team responsible for its operational improvement. In 2017, he also played a pivotal role in AMMAN acquiring a controlling stake in ASX-listed Macmahon Holdings Ltd and served as a Non-Executive Director from 2017 to 2023.
Before co-founding AMMAN in 2015, Alexander served as President Director, and Chief Executive Officer of PT Borneo Lumbung Energi & Metal Tbk (“Borneo”), an IDX-listed metallurgical coal producer. During his tenure at Borneo, he played a crucial role in acquiring a controlling stake in LSE-listed Bumi PLC (“Bumi”) in 2011. From 2012 to 2015, he served as a Non-Executive Director at Bumi and held board positions in various Bumi subsidiaries such as IDX-listed PT Berau Coal Energy Tbk, PT Berau Coal, IDX-listed PT Bumi Resources Tbk, PT Kaltim Prima Coal, and PT Arutmin Indonesia.
Alexander holds bachelor’s and master’s degrees in economics from Boston University, and he began his career as an investment banker at Lazard Frères & Co.
Arief, a Singaporean citizen, brings extensive expertise from the financial-services and corporate sectors to his role. His career began at Goldman Sachs New York in 1991, where he later led the firm's investment-banking operations in Southeast Asia. Arief was a member of the Commitment Committee overseeing investment banking transactions across Asia (excluding Japan).
Prior to joining AMMAN, Arief served as Managing Director and board member at Rajawali Corpora, an Indonesian conglomerate with diverse investments spanning oil-palm plantations, mining, hotels, luxury properties, transportation, infrastructure, and media. During his tenure, Arief held key roles on various committees including Finance and Investment, Ethics, Audit, and Risk Management, as well as the Management Board.
Arief holds dual bachelor's degrees in finance and engineering from the University of Pennsylvania, graduating summa cum laude. He furthered his education with an MBA from Harvard Business School. Arief was appointed Director of AMMAN in February 2021, bringing his wealth of experience to guide the company's strategic vision and growth.
David Gibbs, an Australian citizen, brings over 45 years of international experience in large-scale mining across various commodities including copper, gold, diamonds, uranium, coal (thermal and coke), talc, and nickel laterite. His extensive career spans both underground and open pit mining operations in South Africa, Namibia, Papua New Guinea, Australia, Thailand, and Indonesia.
David's expertise encompasses feasibility study management, mine planning, operations, productivity improvement, cost reduction, research and due diligence, strategic planning, and project evaluation and development. He holds a BSc Honours degree in mining engineering and certifications including Mine Manager Certificates for Western Australia and South Africa. David is an Associate of The Royal School of Mines (ASRM) and a Chartered Engineer (C Eng).
David was appointed Director of AMMAN in February 2021. In addition to his role at AMMAN, David serves as a Non-Executive Director of Macmahon Holdings Ltd, an ASX-listed mining contractor, since 2023.
Dr. Naveen, an Indian citizen, brings over 25 years of executive experience in global mining operations, commercial and commodity trading, acquisitions, mergers, and strategic development to AMMAN. He has held significant management roles across various industrial sectors.
Before joining AMMAN in 2016, Dr. Naveen served as CEO of RAK Minerals and Metals Investments FZC, United Arab Emirates, from 2007 to 2011, followed by a role as President Director of Trimex International Indonesia from 2012 to 2016. He holds a master's degree in chemistry and a doctorate from Jadavpur University, India. Dr. Naveen also completed the Advanced Management Program at Harvard Business School. Dr. Naveen was appointed Director of AMMAN in February 2021.
Irwin, an Australian citizen, brings over two decades of global experience in the mining, earthworks, and engineering sectors to AMMAN. Since joining in 2016, Irwin has played a key role in operational and cultural transformation during the ownership transition.
Before his tenure at AMMAN, Irwin held senior management positions at Leighton (Thiess) Contractors and served as a lead advisor for the HKND Group on the Nicaragua Grand Canal project—the largest earthworks and infrastructure project at the time. He also served as Project Director and Head of Mining for ASX-listed Hunnu Coal Limited and SET-listed energy company Banpu, overseeing coking coal mines in Mongolia.
Irwin is a member of the Australian Institute of Mining and Metallurgy and is qualified as a Competent Person for JORC Code reporting. He holds multiple degrees in engineering with honors and commerce (corporate finance, financial investment, and accounting) from the University of Western Australia. Irwin assumed the role of Director at AMMAN in February 2021.