Our Firm
Ambassador Hans H. Hertell
Founder & Chief Executive
Officer
George Villar
Co-Founder, Chief Operating
Officer & Chief Legal Officer
An attorney with over 30 years’ experience in government, public affairs, business, and banking, Ambassador Hans H. Hertell was sworn in as the United States Ambassador to the Dominican Republic on November 8, 2001. When he finished his tour on May 1, 2007, Ambassador Hertell was the second longest serving U.S. Ambassador and he was awarded the prestigious Cobb Award for Excellency in Diplomacy by the Department of State.
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Ambassador Hertell has been involved in infrastructure projects all over the world. Ambassador Hertell was principally responsible for, among others, the development of the 263 MW electric LNG co-generation facility in Puerto Rico (the "EcoEléctrica Project") and the 500 MW electric fossil fired facility in Colombia (the "Northern Energy Node Project"). Additionally, Ambassador Hertell is directly involved in free economic zones development ("Induparks"), power projects ("Northern Energy Node") Mining projects ("Colcco") and distributed generation projects ("Exxius").
Before being an Ambassador, Mr. Hertell’s experience includes being the Managing Director for Latin America and the Caribbean for Black, Kelly, Scruggs and Healey, a government and public affairs company based in Washington, D.C. He was President of a publicly traded company, Ponce Federal Bank (NYSE), and a founding partner of the third largest full service law firm in Puerto Rico, Goldman, Antonetti, Ferraiuoli, Axtmayer and Hertell. He has also served on the Board of Directors of the Federal Home Loan Bank of New York. Amb. Hertell holds a Bachelor of Arts degree from Fordham University of New York, and a Juris Doctorate from the University of Puerto Rico.
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George Villar serves in a senior leadership role encompassing structured finance, mining technologies, and general counsel responsibilities, bringing more than 35 years of cross-disciplinary experience spanning finance, engineering, construction, and resource development. His background uniquely combines technical rigor with legal and financial structuring expertise, enabling him to guide complex transactions and projects from origination through execution while maintaining strict governance, compliance, and risk controls. He holds a master’s degree in Engineering and an MBA with a concentration in structured finance, providing a strong foundation for integrating legal, financial, and operational considerations.
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In his capacity as CLO, George oversees legal strategy, contract structuring, regulatory navigation, and transactional risk management across Chimera’s investment and mining technology platforms. He plays a central role in negotiating and structuring agreements related to mining technologies, processing, and refining, including securing a rare earth element processing agreement for Chimera Minerals Inc., a subsidiary within Chimera Capital’s circular mining portfolio.
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George’s structured finance expertise includes arranging and overseeing complex capital stacks involving debt, equity, and hybrid instruments for large-scale industrial, infrastructure, and mining-related projects. Over his career, he has directed or supported more than $2.7 billion in projects across sectors such as gold mining, advanced laboratories, mission-critical facilities, government and defense contracting, and heavy industrial development. Having served as an Owner’s Representative, bank representative for the U.S. Small Business Administration, and for domestic and international financial institutions, George brings a lender-informed perspective to legal structuring and capital deployment. His leadership ensures that Chimera’s mining technology and resource investments are legally resilient, financially sound, and positioned for long-term operational success.
Charles Birnbaum
Chief Financial Officer
Kerri Darling
Treasurer & Chief Technology Officer - Mining Technologies
Charles Birnbaum serves as Chief Financial Officer, bringing a broad and disciplined financial leadership background across capital markets, structured finance, trading operations, and institutional financial services. His career includes senior roles in Wall Street bond trading environments where he was responsible not only for active portfolio management, but for the financial oversight, controls, and performance of high-volume trading operations executing over a billion dollars in annual transactions.
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In his leadership roles, Charles managed the full financial lifecycle of trading and investment activity, including capital allocation, liquidity management, risk controls, trade execution oversight, reconciliation, and regulatory compliance. He developed and enforced investment and operational guidelines, monitored primary and secondary markets, and ensured accuracy, transparency, and timeliness across all financial reporting and transaction processes. His experience provides a strong foundation in financial governance, internal controls, and market-driven decision making.
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Beyond traditional capital markets, Charles has structured and brokered hundreds of millions of dollars in sustainable energy and natural gas transactions for large industrial institutions. He has also built and operated a specialized funding company focused on factoring energy accounts receivable, creating alternative liquidity solutions for counterparties. As CFO of Chimera, Charles oversees financial strategy, capital planning, and operational scalability, supporting disciplined growth, resilient financial infrastructure, and long-term value creation across the firm’s investment platforms.
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Kerri Darling serves as Treasurer and Chief Technology Officer of Mining Technologies, where she plays a central role in advancing Chimera’s leadership in circular mining, strategic metals recovery, and next-generation extraction systems. With deep, hands-on expertise across mining operations, refinery and processing technologies, and resource beneficiation, Kerri leads the development, validation, and deployment of proprietary mining and extraction technologies. Her work focuses on improving recovery efficiency, reducing environmental impact, and enabling economically viable extraction from complex, low-grade, or previously uneconomic resources.
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Kerri brings a rare combination of technical mining knowledge and financial acumen, allowing her to bridge engineering execution with capital strategy. She possesses a strong command of hydrometallurgical and pyrometallurgical process flows, refinery integration, and metallurgical optimization, alongside a nuanced understanding of how mining technology decisions directly affect project economics. In her dual role, she structures and delivers complex critical metals projects, secures debt and equity financing for resource development initiatives, and evaluates strategic opportunities across both conventional mining assets and emerging circular and secondary resource streams.
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As Treasurer, Kerri works closely with Chimera’s Board of Directors to shape financial strategy, design strategic account and project finance plans, and align capital allocation with long-term operational and technological objectives. Concurrently, as Chief Technology Officer of Mining Technologies, she ensures that client requirements, feedstock characteristics, and market demands are tightly integrated into Chimera’s technical solutions, pilot programs, and commercial project proposals. Her leadership reinforces Chimera’s position at the intersection of mining technology, sustainable extraction, and disciplined capital deployment—driving durable value creation across the firm’s global mining portfolio.
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Frank E. Orenstein
Managing Director, Hospitality, Gaming & Resorts Development
Paul Drexel
Chief Investment Officer
Mr. Orenstein’s career encompasses many landmark events in the hotel industry. As Vice President of Development for Four Seasons Hotels Limited, Mr. Orenstein initially assisted in developing the original Four Seasons’ concept and developed the first Four Seasons’ properties in the United States, Canada and Europe including the Four Seasons on Hyde Park Corner in London. As a member of the Executive Committee, he was instrumental in Four Seasons’ significant growth around the world.
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In 1979, Mr. Orenstein left Four Seasons to become a hotel developer enjoying considerable success throughout North America and Europe. His many successful transactions include: the development and sale of Toronto’s prestigious five-star King Edward Hotel; the development of six commercial hotels in partnership with Novotel Division of Accor, S.A.; the acquisition of over 5,000 hotel rooms for one of North America’s largest budget operators; the development and sale of a luxury budget chain and the sale of a five-star resort in Jamaica.
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Frank Orenstein also carried led the expansion of Days Inns in Canada and Europe and the acquisition for Grand Heritage Hotels of the Four Seasons’ position in the Clift Hotel San Francisco. Mr. Orenstein has been responsible for the development of over $1 billion in hotel real estate and has raised in excess of $400 million in equity for various hotel related projects.
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Mr. Orenstein has also recently completed the development of the $100 million Four Seasons Resort and Vacation Club in Scottsdale Arizona. The site selection, concept, development and financing was undertaken by Mr. Orenstein who was a partner with Four Seasons and other private investors. Mr. Orenstein subsequently became Vice-Chairman of the Park Plaza Hotels and Resort in partnership with Olympus/Hicks Muse. The partnership was responsible for expansion of the Park Plaza and Park Inn brands world-wide and subsequently sold their interest in the 200 hotel chain portfolio to Carson Hotels and Resorts. Mr. Orenstein is a graduate of Toronto & Queens University Law School and resides in Palm Beach, Florida.
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Paul Drexel serves in a Chief Investment Officer capacity, bringing more than 25 years of experience across capital deployment, asset acquisition, project finance, and operational optimization within large-scale infrastructure and renewable energy investments. His background spans the full investment lifecycle, from sourcing and underwriting opportunities to overseeing execution, performance optimization, and long-term value realization. Paul is particularly recognized for his ability to align technical realities with disciplined investment strategy, ensuring capital is deployed into assets that deliver durable, risk-adjusted returns.
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Throughout his career, Paul has led investment efforts in multi-megawatt solar and infrastructure projects, where he evaluated project economics, structured acquisitions, and guided capital allocation decisions through design, construction, and commissioning. He has implemented data-driven performance and Continuous Improvement (CI) monitoring frameworks to protect investor returns, enhance asset efficiency, and improve operational transparency post-deployment. His investment oversight has directly contributed to reduced capital intensity, improved margins, and stronger long-term asset performance.
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Paul’s foundation in global commodity trading and international supply chain management informs his investment perspective, particularly in evaluating procurement risk, cost structures, and cross-border execution. Having worked extensively with Asian markets and international counterparties, he brings a global lens to sourcing, pricing, and strategic partnerships. In addition, his experience across both private and public sectors—securing corporate credit, structuring debt facilities, managing acquisitions, and working with government entities—positions him as a disciplined steward of capital. As Chief Investment Officer, Paul drives investment strategy, portfolio construction, and capital optimization to ensure projects meet rigorous financial, operational, and strategic objectives while supporting long-term sustainable growth.
Robert Donnelli
Managing Director, Structured Finance & Biomedical Sciences
Robert has a distinguished career spanning over 25 years in the financial industry, with a focus on technologies, emerging market strategies, and the healthcare sector. As a results-oriented entrepreneur, he has built a reputation for identifying and capitalizing on cutting-edge opportunities in biotechnology, pharmaceuticals, and digital healthcare. His expertise extends to investment strategies that bridge technology and finance, enabling companies to innovate and thrive in fast-evolving markets.
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As a former partner of the Stonegate Berkeley West Arbitrage Fund, Robert demonstrated his ability to manage complex investment strategies, driving significant returns for his clients. He was also a founding partner of Tuscano Partners, a private investment research firm that specialized in sourcing transformative technologies, with a particular emphasis on healthcare innovations. This role allowed him to combine his deep financial expertise with a keen eye for disruptive technologies in the medical field.
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Robert’s leadership experience includes serving as CEO of the Boloto Group, an investment education and technology incubator dedicated to empowering consumer markets. In this capacity, he fostered the development of innovative solutions, guiding startups through incubation to commercialization. His strategic vision helped these companies navigate the complexities of emerging markets while building sustainable business models.
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Before his work in technology and healthcare, Robert was a partner in several notable firms. At Riptide Trading, he played a key role in advancing equity and equity options execution and order management software. As a partner in Mercury Shamrock, an electronic equities market-making firm, Robert contributed to the firm’s success in navigating the rapidly evolving electronic trading landscape. He also served as a primary equity options market maker on the Chicago Board Options Exchange (CBOE), where he honed his expertise in market dynamics and trading strategies.
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Throughout his career, Robert has consistently demonstrated his ability to lead, innovate, and deliver results in highly competitive industries. His diverse background in finance, technology, and healthcare positions him as a visionary leader with a proven track record of success.
Juan Serrat
Managing Director, Mining Technologies & Operations
Juan Serrat is a seasoned mining executive with more than 25 years of international experience spanning mining technology, operations, and project development across gold and platinum group metals (PGMs). His career has been defined by hands-on leadership in complex mining environments, where he has overseen the full lifecycle of operations—from exploration and mine development through processing, refining, and downstream optimization. He brings deep operational insight across diverse jurisdictions, navigating technical, regulatory, and logistical challenges in both mature and emerging mining regions.
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Throughout his career, Juan has led and advised multidisciplinary teams responsible for metallurgical processing, plant design, production optimization, and recovery efficiency for precious metals. His expertise covers conventional and advanced extraction methods, beneficiation, smelting, and refining, with a strong focus on improving yields, reducing operational risk, and enhancing cost efficiency. Known for bridging engineering rigor with practical execution, he has consistently delivered scalable solutions that align operational performance with commercial objectives.
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In his role with Chimera Capital Partners, Juan contributes strategic and technical leadership to mining and resource-focused initiatives, supporting the evaluation, development, and optimization of precious metals projects. His international perspective, combined with deep technical credibility, enables Chimera to pursue innovative and responsible mining strategies, including the integration of advanced technologies and circular mining concepts. Juan’s approach emphasizes operational excellence, sustainability, and long-term value creation across the gold and PGM supply chain.
Advisory Board Management
Nigel Parker
Senior Advisory Board Member,
Estate Management/Mining
Yair Oren
Advisory Board Member,
Technology/Communications
Nigel Parker is a multifaceted professional with extensive industry knowledge and strong managerial capabilities, which he has successfully applied across a wide range of assets and projects. His career began in insurance and financial services with Prudential, where he gained a solid foundation in managing financial portfolios. He later pursued a degree in Estate Management at Reading University, further expanding his expertise in asset management and development.
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Nigel firmly believes that the success of any project lies in the hands of the people managing it. Over the years, he has had the privilege of collaborating with a diverse range of entities, including EPC (Engineering, Procurement, and Construction) companies, family offices, government agencies, and family trusts. His work spans asset management for individual projects as well as for larger groups aiming for growth, diversification, and new opportunities in the market.
One of Nigel’s key strengths is his ability to identify and create added value at every stage of a project’s lifecycle. Whether it’s during the origination, planning and permitting, contracting, or sales and marketing phases, he brings a keen eye for detail and a strategic approach that enhances project outcomes. His expertise is not limited to just managing existing assets—Nigel is skilled at finding untapped opportunities that drive value and growth.
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In addition to his asset management skills, Nigel works closely with project owners to model business plans that are attractive to investors. His deep understanding of capital markets, combined with his strategic insights, enables him to craft plans that not only secure funding but also generate sustainable profits for all stakeholders involved. By bridging the gap between vision and execution, Nigel ensures that projects are not only feasible but also financially rewarding.
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With a career marked by a diverse portfolio of successful projects and partnerships, Nigel Parker continues to be a sought-after advisor for those looking to navigate the complexities of asset management and project development. His ability to blend strategic thinking with practical execution makes him a valuable asset to any team aiming for long-term success.
Yair is a seasoned innovator, entrepreneur, and executive with over 30 years of experience, primarily in the technology industry. His career is marked by a deep understanding of cutting-edge technologies and a track record of success in both founding and scaling businesses.
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Yair's leadership and technical vision were pivotal during his time as CTO of MobileAccess Networks, a company specializing in in-building wireless solutions. Under his guidance, MobileAccess grew its annual sales from $3 million to over $50 million, leading to its acquisition by Corning in 2008. His ability to drive innovation while scaling operations made him an invaluable asset to the company during a period of rapid growth.
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Before his tenure at MobileAccess, Yair co-founded and served as CTO of Chromatis Networks, an optical networking company that revolutionized metro optical networks. Chromatis’ groundbreaking technology caught the attention of Lucent Technologies, which acquired the company in 2000 for an impressive $4.75 billion. Following the acquisition, Yair continued to contribute his expertise as CTO of Lucent's Metro Optical Networking Unit, where he played a key role in shaping the company's strategic direction in the optical networking space.
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Prior to founding Chromatis, Yair served as Chief Architect and head of Software Development for Scorpio Communications, an ATM switching company that was acquired by US Robotics in 1996. His work at Scorpio Communications cemented his reputation as a visionary technologist capable of driving forward-looking innovations in highly competitive markets.
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Yair’s career began with six years in an elite technological unit of the Israeli Army, where he managed mission-critical system development projects. This experience provided him with a strong foundation in project management, system design, and cutting-edge technological development—skills that he would carry forward into his civilian career.
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A highly respected figure in the tech world, Yair holds a B.Sc. (Summa Cum Laude) and an M.Sc. in Computer Science from the Technion, Israel’s premier technological institute. He is also the author of several patents in areas such as ATM switching, optical networking, and wireless systems, underscoring his contributions to the advancement of these technologies. Yair's rich blend of entrepreneurial experience, technical expertise, and leadership in both early-stage startups and large corporations continues to make him a valuable asset to Chimera.