The paper examines the importance, conceptual basis, and possible improvement of recommended principles and methodological approaches for the justification of key cut-off parameters as applied to multicomponent ore deposits, in the context of revising official regulatory and methodological documentation of the State Commission on Mineral Reserves.

The main contradictions and shortcomings of the existing documentation are identified. These are largely identified by the inherent complexity of the problem and by the widespread use in both literature and industrial practice of the concepts of “primary” and “by-product” components of raw materials, which lack rigorous scientific justification and are interpreted inconsistently by specialists.

The study concludes that a more comprehensive and detailed analysis of all available expert proposals is required to address this exceptionally complex issue, particularly with respect to the allocation of direct and indirect costs to each valuable component when determining its minimum industrial grade.

A comparative analysis of approaches proposed by different researchers and practitioners for defining minimum industrial grades of by-product components in multicomponent raw materials intended for integrated processing is presented. The concept of the maximum (reject) content of each primary and by-product valuable component is introduced and defined. This parameter is determined based on the condition of cost recovery through direct incremental costs associated with organizing its production.

The maximum (reject) contents are applied in addition to the minimum industrial grade of the conditional (primary) component and, in terms of their definition and purpose, correspond to the approach recommended by the State Commission on Mineral Reserves for the analytical calculation of component contents. When determining the minimum industrial grade of the conditional component, only those valuable components of the multicomponent raw material whose contents exceed the corresponding maximum (reject) values should be included in the calculation.

Examples of determining maximum (reject) contents for valuable components from deposits in different industrial sectors are provided, including cases that formed the basis for the approval by the State Commission on Mineral Reserves of commercial reserve estimates with a high level of confidence.