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 an experienced Accounts Payable Manager to lead Mariana Minerals’ accounts payable operations and help build a scalable, technology-enabled procure-to-pay function. This position is responsible for ensuring the timely and accurate processing of supplier invoices, compliance with company purchasing policies and internal controls, and leading a high-performing AP team.
The ideal candidate combines strong operational accounting experience with a continuous-improvement mindset and enjoys building efficient processes that leverage automation. As Mariana continues to grow, this role will play a key part in implementing best-in-class procure-to-pay practices, improving vendor relationships, strengthening internal controls, and supporting the company’s readiness for continued growth.
This role will work closely with Procurement, Operations, Accounting, Treasury, FP&A, and business leaders across multiple operating locations.
WHAT YOU’LL DO
ACCOUNTS PAYABLE OPERATIONS
- Supervise and assist in the daily processing of vendor invoices across multiple legal entities.
- Ensure invoices are processed accurately, completely, and in accordance with company policies and payment terms.
- Ensure three-way matching of purchase orders, goods receipts, and vendor invoices.
- Review invoice coding for accuracy, including general ledger accounts, departments, projects, entities, and budget classes.
- Manage invoice queues and ensure service-level expectations for invoice processing are achieved.
- Coordinate weekly payment proposals with Treasury while supporting working-capital objectives and vendor relationships.
- Monitor accounts payable aging and proactively
VENDOR MANAGEMENT
- Serve as the primary escalation point for vendor inquiries, account statements, and payment disputes.
- Build strong relationships with key suppliers while ensuring consistent communication regarding payment status.
- Coordinate the resolution of invoice discrepancies with Procurement and operational teams.
- Oversee vendor onboarding documentation, including W-9 or W-8 forms, banking information, tax forms, certificates of insurance, and other required support.
- Prepare and complete vendor credit applications to establish or expand supplier credit terms.
- Assist in maintaining an accurate vendor master and support vendor due-diligence processes.
INVOICE APPROVALS AND EXCEPTION MANAGEMENT
- Supervise, coach, mentor, and develop Accounts Payable staff.
- Establish performance expectations and monitor individual and team productivity, quality, and timeliness.
- Conduct regular performance reviews and provide ongoing feedback and coaching.
- Develop cross-training plans to ensure operational continuity and appropriate coverage.
- Promote a culture of customer service, accountability, collaboration, and continuous improvement.
TEAM LEADERSHIP
- Supervise, coach, mentor, and develop Accounts Payable staff.
- Establish performance expectations and monitor individual and team productivity, quality, and timeliness.
- Conduct regular performance reviews and provide ongoing feedback and coaching.
- Develop cross-training plans to ensure operational continuity and appropriate coverage.
- Promote a culture of customer service, accountability, collaboration
PROCESS IMPROVEMENT AND INTERNAL CONTROLS
- Identify opportunities to automate invoice processing, approval workflows, and exception handling.
- Support the implementation and optimization of AP automation tools, OCR technologies, and ERP workflows.
- Develop and maintain standard operating procedures, desk procedures, and process documentation.
- Ensure compliance with internal controls, segregation of duties, procurement policies, and payment authorization requirements.
- Support internal and external audit requests and remediation activities.
- Monitor key performance indicators and recommend
REPORTING AND ANALYTICS
- Prepare and report key Accounts Payable metrics, including:
- Invoice processing cycle time and backlog
- Percentage of invoices supported by purchase orders
- Outstanding approval aging
- Vendor aging
- Non-PO invoice volume
- Provide regular reporting and recommendations to Finance leadership to improve operational efficiency and support decision-making.
DESIRED QUALIFICATIONS
- Bachelor’s or Associate’s degree in Accounting, Finance, Business Administration, or a related field
- Five or more years of progressive Accounts Payable experience, including at least two years supervising or leading AP staff
- Experience in manufacturing, mining, energy, industrial, construction, or another asset-intensive industry is preferred
- Strong understanding of procure-to-pay processes, invoice matching, vendor management, and payment controls
- Experience with ERP systems such as Odoo, NetSuite is preferred
- Experience with AP automation platforms and OCR technologies is highly desirable
- Strong knowledge of internal controls, segregation of duties, and financial compliance
- Experience implementing process improvements and automation initiatives
- Excellent organizational skills and the ability to manage competing priorities in a fast-paced environment
- Strong analytical, problem-solving, interpersonal, and communication skills
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.