Stuart Simmons is a consulting geoscientist and a research professor who has been working on epithermal deposits and geothermal resources for over 30 years. Much of this effort has been directed at understanding ore-forming processes based on investigations of New Zealand geothermal systems and large epithermal deposits in the circum-Pacific region. His published work has appeared in Economic Geology, Geology, Geothermics, Mineralium Deposita, Nature, and Science. Stuart is currently based at the Energy and Geoscience Institute at the University of Utah, where he investigates geothermal resources and critical metals in produced thermal waters in the western USA. He received his PhD in Economic Geology from the University of Minnesota.