Critical Minerals
Approved Auditors for Critical Mineral Supply Chains
Companies sourcing critical minerals need auditors who understand both the standard and the mine site. TDi Sustainability has conducted second- and third-party audits across gold, cobalt, copper, nickel, zinc, molybdenum, tin, tantalum, tungsten and other minerals for more than two decades, and is an approved auditor for several of the industry’s leading assurance schemes.
TDi is an approved auditor for:

- The Copper Mark
- The Nickel Mark
- The Zinc Mark
- The Molybdenum Mark
- Bettercoal
- London Metal Exchange (LME) Track A and Track B
- Mining Association of Canada (MAC) Toward Sustainable Mining (TSM) Protocols
- EO100 Standard for Responsible Energy Development
- RMI Responsible Minerals Assurance Process (RMAP) and Downstream Assessment Programme (DAP)
TDi has conducted assessments against:

- IFC Performance Standards
- The Lead Battery Code
- UN Guiding Principles on Business and Human Rights
- Voluntary Principles on Security and Human Rights
- IRMA Standard for Responsible Mining
- World Gold Council Responsible Gold Mining Principles
- Fairmined
- Responsible Cobalt Initiative
- Responsible Jewellery Council (RJC) Code of Practices
- OECD Due Diligence Guidance for Responsible Supply Chains of Minerals from Conflict-Affected and High-Risk Areas
Meet some of our audit team members
Standards TDi has helped build
Beyond auditing against existing standards, TDi has directly helped build several of them, including:

- We partnered with the Responsible Minerals Initiative to create its Risk Readiness Assessment (RRA) system.
- We worked with the International Copper Association to create the Copper Mark itself.
- We have developed extensive auditor training for schemes requiring the OECD Due Diligence Guidance conformance in the jewellery industry.
- We were selected to build the Joint Due Diligence Standard for Copper, Lead Nickel and Zinc and its supporting resources and tools.
- TDi led the development of the ASM Cobalt Framework – designed to regulate the flow of cobalt from the Democratic Republic of the Congo (DRC) to global markets.
- We supported the development of the RECOSI Coal Programme (Bettercoal) Assurance System and Platform
- TDi was instrumental in developing the Lead Battery 360° (LB360°) Certification Programme itself – a collaborative initiative with the International Lead Association, Battery Council International, EUROBAT and the Association of Battery Recyclers – and has produced training material to expand LB360°’s pool of assessors.
- TDi set up the Solar Stewardship Initiative (SSI) itself, in partnership with Solar Power Europe and Solar Energy UK – facilitating its design and implementation from initial research through to the creation of its standards, code of conduct, pilot study, assurance system, grievance mechanism, and third-party assessor approval process. TDi remains a permanent member of the SSI Secretariat.
Critical Minerals Supply Chain Audit
Case Studies
FAQs
Critical mineral supply chain auditing
Which standards is TDi an approved auditor for?
TDi is an approved auditor for:
- The Copper Mark
- The Nickel Mark
- The Zinc Mark
- The Molybdenum Mark
- Bettercoal
- London Metal Exchange (LME) Track A and Track B
- Mining Association of Canada (MAC) Toward Sustainable Mining Protocols
- EO100 Standard for Responsible Energy Development
- RMI Responsible Minerals Assurance Process (RMAP) and Downstream Assessment Program (DAP)
Does TDi audit gold, cobalt and copper supply chains?
Yes. We’ve conducted audits and assessments across gold, cobalt, copper, nickel, zinc, molybdenum, tin, tantalum and tungsten supply chains, applying both commodity-specific standards (like the Copper Mark) and cross-commodity frameworks (like the OECD Due Diligence Guidance).
What is the difference between TDi auditing against a standard and TDi helping build a standard?
Auditing means independently assessing whether a client meets an existing standard’s requirements. Helping build a standard means working with the standard-setting body itself to design the framework, assurance system or auditor training in the first place – as TDi did with the Copper Mark and RMI’s Risk Readiness Assessment. These two roles are kept very distinct in our internal governance, but the role we have played in supporting the development of many of the industry’s key standards means that we’re ideally placed to support audit preparation and training.
How experienced are TDi’s auditors?
Our auditors bring decades of combined, on-site experience across dozens of countries and every major mineral supply chain, from artisanal sites to industrial-scale operations. See the named team profiles on this page for specific backgrounds.
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Our auditors bring decades of combined, on-site experience across dozens of countries and every major mineral supply chain, from artisanal sites to industrial-scale operations.