Administrative Assistant

Mariana Minerals

San Francisco, CA

Apply

JOB DETAILS

SKILLS

Administrative Skills, Artificial Intelligence (AI), Automation, Automation Systems, Budget Management, Calendar Management, Communication Skills, Cross-Functional, Detail Oriented, Diversity, Establish Priorities, Executive Assistant Skills , Expense Management, Expense Reports, Identify Issues, Logistics, Microsoft Office, Mining Industry Software, On Site Support, Operational Support, Organizational Skills, Presentation/Verbal Skills, Problem Solving Skills, Supply Chain, Team Player, Time Management, Travel Planning, Willing to Travel, Writing Skills

LOCATION

San Francisco, CA

POSTED

6 days ago

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 Qualifications

1-3 years of administrative or office support experience preferred
Strong organizational skills and attention to detail
Excellent written and verbal communication skills
Proficiency in Microsoft Office
Experience with expense management and calendar systems preferred
Ability to handle confidential information with discretion

Strong time management and prioritization skills
Problem-solving mindset
Professional and service-oriented approach
Adaptability in a fast-paced environment
Team player with a positive attitude

Why Join Us?

At Mariana Minerals, you'll be part of a mission-driven team reshaping the way critical minerals are sourced and supplied globally. You'll have the autonomy to make big decisions, the tools to innovate, and a culture that values ownership, smart automation, and collaboration.
Our culture is built on three principles:

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.

Mariana is an Equal Opportunity Employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. We do not discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, veteran status, or any other protected status.

Administrative Assistant

Mariana Minerals

San Francisco, CA

About the Company

Mariana Minerals

Similar Job Searches