About the role
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 Role We are seeking a highly organized and proactive Administrative Assistant to support day-to-day administrative operations across multiple locations. This role is ideal for someone early in their career who is detail-oriented, resourceful, and eager to grow within an operations or executive support function. The Administrative Assistant will provide calendar and travel coordination, expense management, on-site office support, and serve as backup to the Executive Assistant when needed. This position requires strong communication skills, flexibility, and the ability to manage competing priorities in a fast-paced environment. What You’ll Do Administrative & Calendar Support Assist with scheduling meetings, managing calendars, and coordinating internal and external appointments Help prepare meeting materials, agendas, and notes as needed Support coordination of cross-functional meetings and company events Travel & Logistics Book and manage domestic and international travel (flights, hotels, ground transportation) Handle last-minute travel changes and troubleshoot logistical issues Expense & Reporting Support Prepare and submit expense reports in a timely and accurate manner Reconcile receipts and assist with tracking budgets or spending reports On-Site & Office Support (Multiple Locations) Provide in-office support across multiple sites as needed Coordinate office supplies, deliveries, and facilities-related requests Assist with visitor management and on-site meeting logistics Support internal events and team off-sites Executive Assistant Backup Serve as backup to the Executive Assistant during absences Provide overflow support during high-volume periods Assist with special projects and ad hoc requests Desired