Mariana Minerals

Accounts Payable Manager

About

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.

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