Led · Grant · Mar 2026

Founded in 2019 in Grenoble, Mantle8 develops a suite of proprietary geological exploration tools, notably HOREX®, a multiphysics 4D imaging platform designed to map active subsurface hydrogen systems. The company focuses on identifying accumulations of high-purity natural (geologic) hydrogen and prioritizing prospects for drilling. Mantle8 plans a global exploration and drilling campaign over the next two years financed by the recent €31 million Series A, aiming to perform initial industrial tests to quantify volumes, purity and reservoir quality. Management projects potential production costs around €0.80 per kilogram if commercially viable reservoirs are found. The firm has raised €37 million in total to date and is positioning to demonstrate that identified systems can produce sustainable, commercially exploitable hydrogen flows.