Job description

🎯 The role
As Chief Exploration Officer, you join the Mantle8 leadership team and own the entire exploration value chain — from global map leads to drilled wells, prospect selection, drilling preparation and field execution.
This role requires a rare profile: the technical credibility of a transversal geoscientist (structural geology, geochemistry, geophysics, reservoir) combined with the operational discipline of a project manager and the entrepreneurial DNA of someone who does the work themselves.

📋 Your missions
Define & manage the exploration strategy
• Establish Mantle8's strategy and technical roadmap in line with our ambition for global leadership.
• Define and develop the criteria, methodologies and ranking framework to evaluate Areas of Interest (AoIs) on a global scale.
• Be the key strategic partner to the CEO and executive team on all technical and portfolio decisions.
Manage the portfolio: from play assessment to prospect drill-ready
• Manage the complete exploration funnel (Europe, Middle East, Africa, North America): regional evaluation, lead generation, ranking and maturation towards drilling.
• Contribute personally to the geological, geophysical and geochemical evaluations of the most strategic prospects — hands-on technical role.
• Continuously prioritize the overall portfolio: which AoIs are progressing, being paused, or abandoned, on which milestones.
Prepare and execute drilling campaigns
• Bring “drill-ready” prospects to the spud: well design, prognosis, technical alignment with industrial partners.
• Co-pilot the drilling campaign with partners and Project Directors, owner of technical decisions throughout the life cycle of the well.
• Capitalize the results of wells in the portfolio: updating geological models, recalibration of the play assessment.
Build & lead the technical function
• Recruit, structure and lead the exploration team — New Ventures (early stage) and Maturation (late stage).
• Operate with a small team in the initial phase: produce substantial technical work, set the level of excellence, recruit as the portfolio grows.
• Master, challenge and evolve Mantle8 workflows, tools and technical standards (modeling stack, AI-assisted interpretation, data management).
Be the technical voice — partners, investors & authorities
• Pitch and defend the Mantle8 exploration thesis to demanding audiences: industrial partners (O&G majors, mining), investors, sovereign financiers, host country authorities, scientific community.
• Manage technical due diligence with potential SPV partners; structure data rooms for each prospect.
• Represent Mantle8 in key technical forums and contribute to the credibility of the natural hydrogen industry.
Fuel decision-making
• Develop and maintain the technical models, decision frameworks and probabilistic assessments underlying each Go / No-Go in the portfolio.
• Provide a strategic view on technical risk, capital allocation and sequencing of exploration expenditures.

Profile required

✅ Profile wanted
Essential
• Significant experience in subsurface exploration (O&G or adjacent industry: geothermal, CCUS, lithium, helium, natural hydrogen) with a track record of managing real exploration portfolios.
• End-to-end experience across the entire chain: play assessment, lead generation, prospect & reservoir evaluation, drilling preparation and execution. You have personally taken prospects from a regional map to a drilled well.
• Deep technical expertise in geosciences, with real transversal mastery in structural geology, geophysics and geochemistry.
• Experience managing a global multi-basin, multi-project portfolio, with competing workstreams across multiple geographies.
• Operational experience in our core geographies (Europe, Middle East, Africa, North America).
• Entrepreneurial and hands-on profile: you do the work, are comfortable with ambiguity, allergic to bureaucracy, and your default mode is to move forward rather than delegate.
• Ability to operate both strategically (board, partners, investors) and at bench level (data, models, well files), and to switch between the two in the same day.

A real plus
• Previous experience in a junior / independent exploration company or as Exploration Manager / VP Exploration in a small operator.
• Direct exposure to natural hydrogen, helium or other innovative subsurface plays.
• Experience with modern exploration technologies: high-resolution / 4D imaging workflows, big data analytics, AI-assisted interpretation.
• Experience in a high-growth startup or scale-up.
• Familiarity with the energy transition or clean-tech ecosystem.
• Availability for relocation in the Grenoble region, French Alps.
• Strong support for Mantle8's mission: to release a new source of sovereign, low-carbon and affordable energy.

Company description

🇬🇧 Mantle8 is a deep-tech exploration company dedicated to unlocking the potential of natural hydrogen as a new clean energy resource.

By combining advanced geoscience, subsurface modeling and cutting-edge simulation technologies, Mantle8 develops innovative exploration methods to identify and evaluate natural hydrogen systems deep within the Earth.
Our multidisciplinary team brings together geoscientists, engineers, data scientists and explorers who share a common ambition: advancing scientific understanding while building the foundations of a new energy frontier.
From regional exploration concepts to prospect generation and technological development, Mantle8 works at the intersection of research, innovation and industrial application to accelerate the emergence of natural hydrogen as part of the global energy transition.
At Mantle8, exploration is not only about discovering new resources — it is about expanding knowledge, challenging assumptions and building solutions for the future of energy.

Why is everything in English if Mantle8 is based in the heart of the French Alps?
Because Mantle8 is an international adventure.
As of March 2026, our team includes 21 people representing 9 different nationalities. This diversity is one of our greatest strengths, and English is the language that allows everyone to collaborate, debate ideas and build things together.
We love our home in the French Alps, but inside Mantle8 our common ground is English — from meetings and technical discussions to emails and, yes, even our jokes.
So if you’re thinking about joining us, English is not just helpful — it’s essential to be part of the conversation.



🇫🇷 À propos de Mantle8

Mantle8 est une entreprise deep-tech d’exploration dédiée à révéler le potentiel de l’hydrogène naturel comme nouvelle ressource d’énergie propre.
En combinant géosciences avancées, modélisation du sous-sol et technologies de simulation de pointe, Mantle8 développe des méthodes d’exploration innovantes permettant d’identifier et d’évaluer les systèmes d’hydrogène naturel présents en profondeur dans la Terre.
Notre équipe pluridisciplinaire réunit géoscientifiques, ingénieurs, data scientists et explorateurs partageant une ambition commune : faire progresser la connaissance scientifique tout en construisant les bases d’une nouvelle frontière énergétique.
De la génération de concepts d’exploration régionaux à l’identification de prospects et au développement technologique, Mantle8 opère à l’interface entre recherche, innovation et application industrielle afin d’accélérer l’émergence de l’hydrogène naturel dans la transition énergétique mondiale.
Chez Mantle8, l’exploration ne consiste pas seulement à découvrir de nouvelles ressources — il s’agit aussi d’élargir la connaissance, de remettre en question les certitudes et de construire des solutions pour l’énergie de demain.

Pourquoi tout est-il en anglais alors que Mantle8 est basée au cœur des Alpes françaises ?
Parce que Mantle8 est avant tout une aventure internationale.
Début mars 2026, notre équipe compte 21 personnes représentant 9 nationalités différentes. Cette diversité est l’une de nos plus grandes forces, et l’anglais est la langue qui nous permet de collaborer, de débattre d’idées et de construire ensemble.
Nous sommes très attachés à notre ancrage dans les Alpes françaises, mais chez Mantle8 notre langue commune est l’anglais — que ce soit pour les réunions, les discussions techniques, les e-mails et, oui, même nos blagues.
Donc si vous envisagez de nous rejoindre, l’anglais n’est pas seulement utile : il est essentiel pour faire partie de l’aventure.

On 6/1/2026