About Mariana Minerals Mariana Minerals is a software-driven minerals company based in San Francisco. The team supplies essential minerals for the energy, artificial intelligence, and defense industries. By combining deep industry knowledge with advanced software, automation, and data strategies, Mariana Minerals is rethinking how minerals reach the world’s most critical sectors. Internship Overview The Process Engineering Intern will join the Pilot Plant Operations team at Mariana Minerals’ San Francisco headquarters. This internship offers the chance to work on meaningful, hands-on projects in mineral processing. Interns conduct benchtop experiments, support pilot plant test runs, and help develop new operational programs. Close collaboration with experienced engineers and subject matter experts is a core part of the experience. This role focuses on building and delivering new solutions, not just supporting existing work. What You Will Do Run experiments in both lab and pilot plant settings to help reduce risks in scaling up minerals processing. Develop, test, and refine approaches to improve product recovery, minimize equipment downtime, control costs, and support health and safety. Work with engineering, management, and software teams to create programs and tools that advance operational goals. Collaborate with cross-functional groups, including operations and analytical labs. Present findings and insights at the end of the internship. What We’re Looking For Current student or recent graduate in chemical engineering, metallurgy, materials science, or a related field. Strong grasp of process design, thermodynamics, and reaction engineering. Hands-on experience in laboratory, pilot plant, or commercial plant settings through coursework, projects, or previous internships. Skilled in experimental design, troubleshooting, and independent analysis of complex data. Clear technical writing, communication, and collaboration abilities. Comfortable adapting to new challenges and working in a changing environment. Why Mariana Minerals? Interns at Mariana Minerals join a mission-driven team working to transform the global sourcing and supply of critical minerals. Every contribution supports a larger vision for the future of the industry.

About Mariana Minerals Mariana Minerals is a software-focused minerals company based in San Francisco. The team delivers essential minerals that support energy, artificial intelligence, and defense technologies. By combining industry expertise with advanced software, automation, and data-driven methods, Mariana Minerals aims to transform the minerals supply chain. Mechanical Engineering Intern – Role Overview The Mechanical Engineering Intern will join the Pilot Plant Operations team at the San Francisco headquarters. This role centers on hands-on work: designing, improving, and optimizing benchtop pilot plant equipment. Interns collaborate with seasoned engineers and domain experts, gaining practical experience that goes well beyond typical support tasks. What You Will Do Create 3D models, layout drawings, and technical documentation for laboratory and pilot plant equipment. Build, test, and refine mechanical solutions to improve equipment performance, reduce downtime, control costs, and support health and safety. Work with engineering, management, and software teams to develop programs and applications that advance Mariana Minerals’ operations. Partner with colleagues from engineering, operations, and controls engineering to reach project objectives. Share your findings and experiences in a final presentation at the end of the internship. Desired Qualifications Currently enrolled in or recently graduated from a mechanical engineering or related degree program. Solid grasp of mechanical design documentation, including equipment specifications, layout drawings, piping diagrams, and CAD models. Hands-on experience designing or supporting industrial equipment such as pumps, piping systems, reactors, separators, filtration systems, or material handling equipment. Ability to design mechanical solutions independently, troubleshoot issues, and analyze complex data sets. Strong technical writing, communication, and teamwork skills. Comfortable adapting to changing priorities and managing multiple tasks in a busy environment. Why Mariana Minerals? Interns at Mariana Minerals join a mission-driven group focused on reshaping the future of critical minerals supply.

About Mariana Minerals Mariana Minerals is a software-driven minerals company based in San Francisco. The team supplies essential minerals that support energy, artificial intelligence, and defense technologies. By combining deep industry experience with automation, software, and data-driven decision-making, Mariana Minerals aims to modernize the minerals supply chain. Internship Overview The Project Engineering Intern will join the Special Operations team to work on projects that directly impact mine operations. This role centers on building and deploying solutions, not just supporting ongoing work. Interns will collaborate closely with engineers and industry experts, contributing to the development of the MineOS product and exploring new technologies. What You Will Do Take ownership of a major operations project, guiding it from problem identification to execution and delivery. Build internal tools, dashboards, or lightweight applications to improve operational processes. Analyze operational data to spot inefficiencies and suggest improvements. Use AI tools such as Replit and Claude for rapid prototyping and solution deployment. Work closely with engineering and operations teams to turn practical challenges into working systems. Iterate on solutions quickly, applying feedback and deploying in real or near-real environments. Share progress, insights, and recommendations during weekly program review meetings. Location This internship is based at Mariana Minerals' San Francisco headquarters.

About Mariana MineralsAt Mariana Minerals, we are revolutionizing the minerals industry with our innovative software-driven approach. Our mission is to provide essential minerals that fuel modern energy, artificial intelligence, and defense sectors. By merging extensive industry knowledge with cutting-edge software, automation, and data analytics, we are transforming the minerals supply chain. Join us as we pioneer the future of mining and mineral processing.The RoleWe are on the lookout for a talented Extractive Metallurgist to become part of our dynamic technical team based in San Francisco. This pivotal role involves the development, enhancement, and scaling of mineral processing systems to support Mariana’s international operations. The ideal candidate will possess robust expertise in process engineering and metallurgy, particularly in zinc or copper, and excel in fast-paced, startup atmospheres that demand creativity, autonomy, and effective problem-solving skills.You will collaborate closely with operations, engineering teams, machine learning specialists, and data scientists to devise innovative solutions that enhance efficiency, recovery rates, and throughput across our projects.Key ResponsibilitiesDesign, test, and refine mineral processing flowsheets for both new and existing initiatives.Lead laboratory, pilot-scale, and plant trials to validate and enhance processes.Analyze metallurgical data to boost recovery rates, efficiency, and cost-effectiveness.Work alongside engineering teams on process design and scaling strategies.Collaborate with data scientists and machine learning engineers to embed advanced analytics and predictive models into process optimization.Assist in the commissioning and ramp-up of new facilities, requiring significant travel to sites.Foster a culture of continuous improvement, innovation, and safety at Mariana.Required QualificationsBachelor's degree in Metallurgy, Chemical Engineering, or Process Engineering.Practical mineral processing experience (zinc or copper preferred, broader experience considered).Demonstrated ability to work independently in a startup environment.Strong analytical and problem-solving skills.

About Mariana MineralsAt Mariana Minerals, we are a pioneering, software-driven minerals company dedicated to supplying the essential minerals that are critical for modern energy, AI, and defense technologies. Our innovative approach redefines how minerals are sourced, refined, and optimized through a blend of deep industrial knowledge and cutting-edge software, automation, and data-driven decision-making. Join us in revolutionizing responsible mineral sourcing and supply.Role OverviewWe are seeking a proactive Hydrometallurgical Process Engineer to contribute to the development of the critical minerals supply chain essential for the global energy transition.As a Hydrometallurgical Process Engineer with Mariana Minerals, you will spearhead the creation and implementation of innovative chemical refining processes. Your role will also involve supporting the development of software for capital project execution and enhancing automated plant optimization. You will be responsible for overseeing equipment scopes from initial concept to design, installation, commissioning, ramp-up, and handover to the operations team.What You Will DoLead hydrometallurgical process equipment scopes from concept development and modeling validation through procurement, detailed engineering, fabrication, installation, commissioning, and ramp-up.Manage relationships with external technology licensors, equipment vendors, and engineering partners to deliver fully integrated and efficient hydrometallurgical refining systems.Develop comprehensive heat and material balances for complex hydrometallurgical process trains, including leaching, solution purification, solvent extraction/ion exchange, precipitation, crystallization, and residue handling.Create hydraulic models and process flow diagrams/P&IDs for hydrometallurgical circuits, ensuring operational efficiency, reliability, and safety.Develop first-principles models of chemical reactors and unit operations (e.g., leach reactors, autoclaves, SX settlers, IX columns, precipitation reactors, filtration systems) to validate scale-up and mitigate risks in commercial designs.Identify, assess, and implement engineering solutions to enhance extraction, purification, and recovery processes under varying chemistries, feedstock qualities, and operating conditions.

About Mariana MineralsAt Mariana Minerals, we are pioneering a software-centric approach to mineral sourcing. Our mission is to deliver the critical minerals essential for modern energy, AI, and defense technologies. We aim to transform the mineral supply chain through innovative software, automation, and data-driven strategies.Join us in our quest to redefine responsible mineral sourcing and supply for a sustainable future.Role OverviewWe are in search of a dynamic and detail-oriented Project Engineer to help develop the critical minerals supply chain that supports the global transition to renewable energy. In this position, you will facilitate communication among engineering, procurement, construction, and operational teams to ensure project success.Your responsibilities will include maintaining project workflows, overseeing document control, tracking engineering and vendor deliverables, coordinating reviews across disciplines, managing RFIs, and creating dashboards for real-time project insights.

Join our dynamic team at Mariana Minerals as a Lab Technician, where you will play a crucial role in supporting our innovative mineral exploration and analysis projects. In this hands-on position, you will be responsible for conducting laboratory tests, preparing samples, and ensuring the accuracy and reliability of data. If you are passionate about science and eager to contribute to exciting discoveries, we want to hear from you!

About Mariana MineralsMariana Minerals is a pioneering software-driven, vertically integrated minerals company dedicated to supplying the essential minerals that fuel modern energy, artificial intelligence, and defense technologies. We are transforming the minerals supply chain by leveraging extensive industry knowledge alongside cutting-edge software, automation, and data-centric decision-making.The RoleAs we build the critical minerals supply chain from the ground up, we seek a highly skilled Senior Machine Learning Engineer to help drive our autonomous operations.Unlike traditional software companies, we are a mining company that develops our own software solutions. Mariana designs, builds, commissions, and operates our own mines and refineries, where we create proprietary chemical processes. Currently, we are producing battery-grade lithium salts from real oil and gas wastewater at our facilities. Our first commercial-scale lithium production facility, Lithium One, is set to commence initial production in the first half of 2027.In your role as a Senior Machine Learning Engineer, you will spearhead the design and implementation of machine learning systems that directly optimize the operations of our mineral refining facilities and guide significant investment and operational decisions. Your contributions will be visible in tangible metrics such as recovery rates, energy consumption, reagent usage, and equipment uptime.The TechThis position involves some of the most compelling applied AI work available today.Our internal platform, PlantOS, utilizes the same reinforcement learning frameworks that power self-driving cars and humanoid robots, adapted for the autonomous and short-interval control of mineral refining circuits. Our models dynamically adjust operating parameters in real time, optimizing for lithium recovery, reagent consumption, energy efficiency, and equipment uptime simultaneously.The working environment is complex and ever-changing; variations in wastewater compositions, ore grades, and aging equipment require the system to adapt continuously. The ultimate objective is to achieve fully autonomous refining operations—when you implement your solutions here, you will witness the physics of the process evolve.What You’ll DoCollaborate closely with Mariana’s process chemistry and engineering teams to develop innovative, data-driven models of core chemical unit operations.Train and deploy reinforcement learning models to optimize operational processes.

About Mariana MineralsAt Mariana Minerals, we are a pioneering minerals company that prioritizes software innovation. Our mission is to provide essential minerals that power the modern energy sector, artificial intelligence, and defense technologies. We are transforming the minerals supply chain by leveraging deep industry knowledge alongside cutting-edge software, automation, and data-driven decision-making.Join us in our commitment to responsible mineral sourcing and supply as we shape the future.Role OverviewWe are seeking a talented Senior Full Stack Software Engineer to lead significant technical projects aimed at developing the next-generation critical minerals supply chain, supporting the global transition to sustainable energy.In this role, you will be responsible for architecting, leading, and delivering software systems that enhance the engineering and construction of vital infrastructure for our minerals supply chain. You will set the technical direction, mentor team members, and oversee the complete delivery of intricate systems. Your key responsibilities will include designing and implementing robust integrations with existing engineering and construction software tools, creating scalable solutions to address internal team challenges, collaborating with ML engineers to implement large language models for unstructured data issues, and leading the creation of a new 'operating system' for the engineering and operation of our mineral processing facilities.This full-stack position requires proficiency in writing production-quality frontend code along with a strong understanding of system design and backend architecture. You will navigate seamlessly between user interfaces and distributed systems, ensuring quality at every layer of the software stack.

Join Mariana Minerals as a Mechanical Maintenance Technician, where you will play a crucial role in ensuring the smooth operation of our machinery and equipment. As part of our dedicated team, you will be responsible for performing routine maintenance, troubleshooting mechanical issues, and implementing effective solutions to enhance operational efficiency.

Join Mariana MineralsAt Mariana Minerals, we are revolutionizing the minerals supply chain. As a software-first, vertically integrated minerals company, our mission is to provide the essential minerals that power modern energy, artificial intelligence, and defense technologies. We harness deep industry knowledge combined with cutting-edge software, automation, and data-driven insights to redefine the way minerals are sourced and processed.Your Role as Staff Product ManagerWe are seeking a dynamic Staff Product Manager to lead a crucial area within MarianaOS. This position is unique as we prioritize recruiting top-tier product managers first and then align them to the most suitable segment of our operations based on their strengths and experiences. Together during the interview process, we will identify the ideal fit for your skills.The potential impact of this position is vast. The mining industry is one of the last major sectors yet to be transformed by modern software technologies. Your work will not merely close feature gaps but will create entirely new workflows and systems. The challenges range from micron-scale chemistry all the way to kilometer-scale infrastructure.By delivering features, you will directly influence metrics such as recovery rates, reagent consumption, construction timelines, and equipment uptime. These are not merely abstract metrics; they reflect the tangible physics of metal production. This role requires on-site engagement and will involve significant travel.About MarianaOSMarianaOS serves as the digital backbone for our mineral projects, overseeing the entire lifecycle from capital project execution to autonomous operations. We are currently focusing on three key domains:MineOS: This platform integrates geological block models, mine planning, fleet management systems, and industrial control systems into a cohesive optimization layer, enhancing autonomous fleet deployment and developing an accurate digital twin of mining sites.PlantOS: Our autonomy platform for fixed-plant mineral processing, including lithium refining and flotation, which employs a reinforcement learning toolkit similar to those used in self-driving technologies for autonomously controlling mineral refining circuits.BizOS: The operational system that streamlines business processes by connecting disparate tools, removing manual handoffs, and providing leadership with real-time insights into project economics and operational performance across the organization.

About Mariana MineralsMariana Minerals is a software-driven, vertically integrated minerals company dedicated to providing the essential minerals that power modern energy solutions, artificial intelligence, and defense technologies. We are transforming the minerals supply chain by leveraging extensive industry expertise alongside cutting-edge software, automation, and data-informed decision-making.The RoleWe are seeking a Senior Technical Recruiter (Contract) to spearhead full-cycle recruitment for pivotal technical and business positions during a crucial growth period at Mariana Minerals. This is a contract role lasting 6-12 months, where your mission will be to devise and implement effective recruiting strategies aimed at attracting, evaluating, and securing top talent in competitive markets.You will collaborate closely with hiring managers and leadership teams, overseeing the recruitment process from start to finish, employing deep market insights, and continuously optimizing recruitment practices through data analysis, systems enhancement, and automation.What You’ll DoManage the entire recruitment process for both technical and non-technical roles, from initial intake to final offer acceptance.Translate complex job specifications into tailored, high-quality sourcing strategies.Develop robust talent pipelines through innovative sourcing methods beyond conventional channels.Work in partnership with hiring managers to ensure alignment, priority setting, and rapid decision-making.Provide candidates with a top-tier, engaging experience marked by clear communication and minimal drop-off rates.Monitor and analyze recruitment funnel metrics (pipeline health, conversion rates, time-to-fill) utilizing Ashby.Proactively identify and address potential hiring obstacles, presenting strategic solutions.Effectively communicate Mariana’s mission, culture, and unique value proposition to attract and secure top candidates.Contribute to the enhancement of recruitment processes, interview methodologies, and overall hiring philosophy.

Role OverviewAt Mariana Minerals, we are on a mission to revolutionize refining processes for critical minerals, playing a pivotal role in the global energy transition. We are in search of a dynamic and driven Process Modeling Engineer who will be integral to this endeavor.In this position, you will take charge of developing, validating, and optimizing heat and material balance models utilizing advanced software such as ASPEN Plus/HYSYS, SysCAD, OLI Studio, or METSIM. You will collaborate closely with R&D, pilot operations, and project execution teams to transform lab and pilot data into robust, scalable process models that are essential for the design of groundbreaking mineral refining facilities.Key ResponsibilitiesCreate both steady-state and dynamic process models to determine heat and material balances for integrated mineral refinery systems using ASPEN, SysCAD, OLI, or METSIM.Automate the sizing of equipment and processes (including reactors, heat exchangers, filters, crystallizers, evaporators, and separators) based on model outputs, linking models to datasheets and other engineering tools.Develop and maintain comprehensive process simulation databases to ensure consistency and traceability among modeling assumptions, test data, and engineering outputs.Calibrate and reconcile models using operational data from pilot plants to ensure model accuracy and predictive validity.Conduct optimization studies to enhance energy recovery, recycling strategies, and material efficiency.Develop dynamic models for validating PLC and DCS programming while assessing buffer sizing throughout the design process.Integrate process models with CAPEX and OPEX estimation tools to streamline techno-economic model development.Document modeling methodologies and results, ensuring clear technical communication for design reviews, techno-economic assessments, and regulatory submissions.

Join Mariana Minerals as a Senior Pyrometallurgical Process Engineer in our San Francisco headquarters. In this crucial role, you will leverage your expertise in pyrometallurgical processes to drive innovation and efficiency in our operations. Collaborate with a team of dedicated professionals to develop and implement cutting-edge solutions that enhance our mineral processing capabilities.

Join Mariana Minerals as a Site Development EngineerAt Mariana Minerals, we are pioneering a software-first approach in the minerals industry, focusing on the essential minerals that drive modern energy, artificial intelligence, and defense technologies. Our mission is to revolutionize the minerals supply chain through a blend of deep industry knowledge, cutting-edge software, automation, and data-driven strategies.As a Site Development Engineer, you will play a crucial role in leading the planning and design of innovative greenfield mining project sites. Your responsibilities will span the entire site development process, from initial site selection and feasibility studies to detailed engineering and execution of construction for state-of-the-art mining and metallurgical processing facilities. You will collaborate across engineering, construction, and project delivery teams to ensure that our sites are designed for optimal constructability, scalability, and sustainable operational performance.

Mariana Minerals, based in San Francisco, supplies critical minerals for sectors such as energy, AI, and defense. The company integrates industrial expertise with advanced software, automation, and data-driven processes to improve how minerals are sourced, refined, and optimized. Mariana Minerals emphasizes responsible mineral sourcing and supply throughout its operations. Role overview The Analytical Systems Engineer will support laboratory analytical capabilities across multiple locations. This position focuses on developing and refining analytical methods, troubleshooting technical issues, and introducing new instruments and procedures. The role calls for a strong analytical background, hands-on mechanical skills, and adaptability in various lab environments. What you will do Enhance and optimize analytical methods at laboratory sites. Troubleshoot and resolve issues with analytical techniques to ensure reliable data and methods. Lead implementation of new instruments, including ICP-OES, ICP-MS, Atomic Absorption, and related equipment. Create, validate, and standardize analytical workflows and methods. Train laboratory staff on equipment usage, analytical techniques, and best practices. Collaborate with cross-functional teams to improve analytical efficiency and maintain data integrity. Evaluate new technologies and suggest improvements for existing systems. Maintain thorough documentation for methods, SOPs, and technical guidelines. Offer technical support for complex analytical challenges within the organization. Requirements Bachelor’s degree in Analytical Chemistry, Chemistry, or a related scientific field (recent graduates encouraged to apply). Experience with ICP-OES, ICP-MS, Atomic Absorption, or similar analytical instruments is preferred. Solid understanding of analytical techniques, sample preparation, and data interpretation. Strong problem-solving abilities and the capacity to work both independently and as part of a team.

Join Our Team at Mariana MineralsAt Mariana Minerals, we are redefining the minerals supply chain as a software-first, vertically integrated minerals company. Our mission is to provide the essential minerals that power modern energy solutions, artificial intelligence, and defense technologies. We leverage our extensive industry expertise alongside cutting-edge software, automation, and data-driven decision-making to innovate the minerals sector.Your RoleWe are on the lookout for an enthusiastic Pilot Plant Technician to enhance our San Francisco Pilot Plant team. In this hands-on role, you will contribute to the design, implementation, and operation of groundbreaking refining processes for critical minerals, while also aiding in the development of software for plant optimization. This position is pivotal in connecting Research & Development with Operations, ensuring our processes are robust, safe, cost-effective, and primed for commercial production. This opportunity is specifically for our weekend shifts.Key ResponsibilitiesCollaborate with engineers and technicians to operate and monitor various chemical processes, including precipitation, filtration, ion exchange, and membrane concentration.Safely manage chemicals, raw materials, and waste streams in accordance with standard operating procedures and regulatory guidelines.Support sampling, conduct quality checks, and perform basic laboratory measurements.Assist in the design, installation, startup, and commissioning of new equipment and processes.Take responsibility for maintaining plant cleanliness and organization, ensuring that workspaces, tools, and equipment are well-kept and ready for operations.Conduct routine maintenance, inspections, and basic mechanical repairs; document findings and actions within a Computerized Maintenance Management System (CMMS).Create and maintain operational documents including procedures, experimental records, and shift reports.

Join Mariana Minerals as a Research and Development Technician, where you will play a vital role in our innovative projects aimed at enhancing mineral processing technologies. You will be responsible for conducting experiments, analyzing data, and collaborating with cross-functional teams to drive our R&D initiatives forward.

About CluelyAt Cluely, we are revolutionizing the way people interact with AI by providing unparalleled advantages in diverse situations. Our innovative desktop assistant leverages screen, microphone, and audio context to deliver insights and suggestions that traditional models fail to offer due to contextual limitations.Our success hinges on two key factors:1) Chatbots are not the ideal interface for multi-modal AI.2) We possess the ability to make anything go viral.About the RoleAs an Engineering Intern at Cluely, you will be immersed in a dynamic environment where our engineering team works six days a week in-person in San Francisco, dedicating 10-12 hours each day. We provide housing within a block of the office to ensure your convenience and focus.Our engineering team comprises both seasoned professionals and ambitious young talent, creating a unique blend of skills and creativity. For more insights into our team, check out this link.Ideal Candidate ProfileYou are among the top engineers globally.You are willing to invest your life in the pursuit of greatness.