30 October 2026

Public comment period open: Proposed revisions to the CIM definition standards for mineral resources and mineral reserves

The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) is pleased to announce the opening of a 60-day public comment period on proposed revisions to the 2014 CIM Definition Standards for Mineral Resources and Mineral Reserves (CIM Definition Standards).

The proposed revisions include three new definitions: exploration target, scoping study and life of mine plan. The CIM Mineral Resource and Mineral Reserve (MRMR) Committee prepared them at the request of the Canadian Securities Administrators (CSA) as part of the CSA Project to Modernize Mineral Disclosure Requirements. These definitions were circulated for public comment in 2025, and the MRMR Committee has reviewed and incorporated the feedback received.

This consultation covers the full revised document. It also includes updates that clarify existing definitions and guidance, align terminology with current international reporting practices, and remove or update outdated content.

The CIM Definition Standards establish definitions and guidance for Mineral Resources, Mineral Reserves and mining studies used in Canada. They are incorporated by reference into National Instrument 43-101 – Standards of Disclosure for Mineral Projects (NI 43-101). The current 2014 CIM Definition Standards can be viewed at mrmr.cim.org.

How to participate

CIM invites all stakeholders, including geoscientists, engineers, regulators, investors and the public, to review the proposed revisions and submit their comments.

Comment period deadline: Monday, January 4, 2027

Submit comments to: jbreaux@cim.org

Access the draft document 

Thank you for your engagement and contributions to this important initiative.