ABOUT MARIANA MINERALS Mariana Minerals is a software-first, vertically integrated minerals company on a mission to supply the critical minerals powering modern energy, AI, and defense technologies. We’re reimagining the minerals supply chain by combining deep industry expertise with advanced software, automation, and data-driven decision-making. The Mobile Maintenance Supervisor is a hands-on working supervisor responsible for leading a team of maintenance technicians and supporting the safety, reliability, and availability of Mariana’s growing mobile mining fleet. This role combines technical leadership, field troubleshooting, crew development, maintenance planning, and day-to-day operational decision-making. The ideal candidate will have a demonstrated track record of hands-on maintenance leadership, strong technical credibility, and a proactive, solutions-oriented approach to working in an evolving operation. They will enjoy solving problems in the field, developing technicians, improving processes, and helping build the systems, practices, and crew culture needed to support a growing fleet. Responsibilities: - Lead, supervise, and develop a team of maintenance technicians while maintaining a safety-first mentality and a strong culture of accountability, teamwork, and continuous improvement. - Conduct safety meetings and workplace inspections, address hazards, and ensure work is performed in accordance with company policies and applicable safety requirements. - Work hands-on alongside technicians to troubleshoot, diagnose, and repair heavy mobile mining equipment, including mechanical, hydraulic, and electrical systems. - Prioritize and coordinate daily maintenance activities based on safety, equipment criticality, production needs, labor, parts, and available resources. - Perform advanced troubleshooting and failure analysis using diagnostic tools, schematics, technical manuals, and equipment documentation. - Drive equipment reliability and availability through preventative maintenance, repair-quality review, equipment-status tracking, and identification of recurring failures. - Coordinate with planners, operations, and vendors to schedule repairs, manage work orders, source parts, and communicate repair requirements and expected downtime. - Train and mentor technicians, provide technical leadership in the field, and provide on-call support as needed, including serving as the senior maintenance representative when leadership may not be onsite. Required Qualifications: - Previous supervisory, lead technician, or crew-leadership experience, with the ability to coach technicians and provide technical direction in the field. - Minimum of 5 years of mining maintenance experience, with strong hands-on experience supporting heavy mobile mining equipment. - Strong troubleshooting and failure-analysis skills across mechanical, hydraulic, and electrical systems, including the ability to read hydraulic and electrical schematics; welding experience is a plus. - Experience with Caterpillar mobile mining equipment and electronic diagnostic tools; familiarity with CAT ET, CAT SIS, and direct experience with CAT 777 haul trucks and/or CAT 992K wheel loaders is strongly preferred. - Strong communication, organization, and problem-solving skills, with the ability to make decisions, take ownership, and work effectively in a growing operation where processes and systems are still being developed. - Experience using maintenance tracking systems and Microsoft Office applications. - Experience with autonomous mining technology is a plus. - Valid driver’s license required. Working Environment and Schedule: - Schedule: 7 days on / 7 days off, working 12-hour shifts. As operations expand, supervisors will rotate between day and night shifts and must be available for on-call coverage as needed. - Work Environment: Approximately 70% fieldwork and 30% office-based work. - Housing & Relocation: Housing and relocation assistance options are available OUR CULTURE IS BUILT ON FOUR PRINCIPLES: Everyone Gets Home Safe. We never put speed or cost ahead of people. Extreme Ownership. We take full responsibility for outcomes, relentlessly driving toward solutions. Engineer Out Requirements, then Automate. We simplify, optimize, and then automate for scale. Share Your Legos. We collaborate openly, share knowledge, and empower each other to build bigger, better solutions. Join us as we build the future of responsible mineral sourcing and supply!