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.

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 MineralsMariana Minerals is a pioneering minerals company that leverages software and automation to revolutionize how critical minerals are sourced, refined, and optimized. Our mission is to supply the essential materials that drive modern energy solutions, artificial intelligence, and defense technologies.By integrating deep industry expertise with cutting-edge technology and data-driven methodologies, we are setting new standards in responsible mineral sourcing. Join us in reshaping the future of mineral supply chains.Role OverviewWe are seeking a passionate and driven Mechanical Engineer to contribute to the development of our critical minerals supply chain, essential for supporting the global energy transition.In this role, you will spearhead the creation and implementation of innovative chemical refining processes, while also supporting software development for project execution and plant optimization. Your responsibilities will encompass designing, constructing, and commissioning pilot and modular commercial-scale plants, formulating first-principles models of refining equipment and processes, and managing equipment scopes from concept through to design, installation, commissioning, and handover to operations.What You’ll DoLead mechanical engineering projects across all phases—from concept and feasibility to detailed design, procurement, fabrication, installation, and commissioning.Develop comprehensive site-wide and area-level plant layouts that optimize equipment arrangement, maintenance access, constructability, safety, and multidisciplinary integration.Prepare mechanical equipment specifications, data sheets, and requisition packages for a wide range of process and solids-handling equipment, while assisting in technical evaluations and vendor selection.Design, assess, and integrate solids-handling and material-conveyance systems, including silos, bins, hoppers, feeders, conveyors, bucket elevators, chutes, and dust-control mechanisms.Assist in the development of 3D models and piping/mechanical interface layouts, ensuring compatibility with process, structural, civil, and electrical engineering requirements.Review vendor drawings and calculations to ensure compliance with mechanical design standards, project requirements, codes, and maintainability criteria.

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 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 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.

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 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 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.

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 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.

Join Harvey as a Senior Technical Recruiter, where you will play a pivotal role in attracting top-tier technical talent to our innovative team. You will collaborate closely with hiring managers to understand their needs, craft compelling job descriptions, and utilize various sourcing strategies to identify and engage potential candidates. Your expertise in the tech recruitment landscape will help us build a diverse pipeline of candidates that align with our company culture and values.

Join our dynamic team at Weekend as a Senior Technical Recruiter. In this pivotal role, you will lead our recruitment efforts to attract top-tier technical talent. Collaborate with hiring managers to understand the unique needs of each role and leverage your expertise to implement innovative recruiting strategies. Your ability to build relationships and connect with candidates will be key to our success.

Join Whatnot as a Senior Technical Recruiter, where you will play a crucial role in shaping our engineering teams by attracting and hiring top-tier talent. Your expertise in technical recruitment will drive our growth and innovation as we strive to build an exceptional platform for our users.In this role, you will collaborate closely with hiring managers, develop sourcing strategies, and engage with candidates to ensure a seamless hiring process. You will be instrumental in enhancing our employer brand and ensuring a positive candidate experience.

About JuiceboxAt Juicebox, we are dedicated to empowering teams to outperform in the competitive talent landscape. In today's AI-driven world, human creativity and expertise are invaluable assets. Successfully navigating recruitment is a critical challenge that can define your success.Our platform is trusted by organizations such as Ramp, Perplexity, and leading AI research labs, serving over 3,000 clients ranging from early-stage startups to Fortune 500 giants.With a remarkable growth trajectory, Juicebox has achieved over $10M in ARR and continues to expand at a rate exceeding 20% monthly. We are proud to be among the fastest-growing AI SaaS companies globally, facilitating thousands of searches daily.Backed by $36M in funding, including a $30M Series A led by Sequoia Capital, our investor portfolio includes industry leaders like Coatue, NFDG, Lux Capital, Y Combinator, and BOND Capital.About the RoleWe are on the lookout for a Senior Technical Recruiter to enhance our Engineering, Design, and Product teams. This is not your conventional recruiting position; as an AI sourcing platform, Juicebox is at the forefront of modern recruitment. You will be a prominent figure in the recruiting community, shaping the intersection of AI and sourcing.Your role will involve defining our external presence through engaging content, community initiatives, and an exceptional candidate experience, positioning Juicebox as the premier destination for elite AI talent.

Join Giga, an innovative voice AI startup, at an exciting juncture as we leverage our recently secured $61M Series A funding to redefine customer experience. With esteemed clients like DoorDash, we are pioneering AI agents capable of understanding emotions, resolving issues in real-time, and scaling seamlessly across large enterprises.Our mission is to establish ourselves as the leading AI platform for enterprise automation, driven by our exceptional voice superintelligence. To realize this vision, we are on the lookout for talented engineers who are eager to make an impact.At Giga, you will work on projects that influence millions daily, enjoying the autonomy to drive real change. With exceptional founders and a roadmap for generational success, this is a unique opportunity to contribute to a groundbreaking company. Learn more about our journey:Voice AI startup Giga raises $61M Series ADoorDash and Giga PartnershipOur AI agents are trusted by leading B2C companies globally, including DoorDash, as they tackle complex support and operations workflows across voice, chat, and email. If this resonates with you, we encourage you to apply!

As a Senior Technical Recruiter at Superhuman, you will spearhead the technical recruitment process, ensuring we attract and retain top-tier talent. This role requires in-person collaboration in the San Francisco Bay Area two days a week.About SuperhumanSuperhuman is an innovative AI productivity platform, now part of Grammarly, dedicated to unlocking human potential through advanced technology. Our suite of applications integrates seamlessly with over 1 million services, empowering more than 40 million users globally—including individuals, organizations, and educational institutions—to eliminate busywork and focus on what truly matters. Explore more at superhuman.com and discover our values here.The OpportunityIn this pivotal role, you will take full ownership of the technical recruiting funnel, from sourcing candidates to onboarding. You will strategically enhance every phase of the recruitment process—engaging passive candidates, qualifying prospects, coordinating interviews, and managing the offer process.

Join Our Team at Ivo!At Ivo, we understand that contract negotiation can be a complex and time-consuming process. Our innovative solutions leverage cutting-edge large language models to streamline and enhance contract negotiations, making them faster and more efficient.With a proven 85%+ win rate in head-to-head trials, our market-leading product is trusted by top companies worldwide. We are in search of a talented Senior Technical Recruiter to elevate our recruitment strategy and support our ambitious growth objectives. In this pivotal role, you will collaborate closely with our technical and go-to-market (GTM) leaders, champion innovative sourcing techniques, and ensure an outstanding candidate experience throughout the recruitment process.