In the mining industry, the distinction between mineral resources and mineral reserves is important in project valuation and decision-making in investment. Though the two are often used in a casual sense, they refer to different classifications that are technically and economically significant.
Mineral resources
They are defined as concentrations of naturally occurring materials in or on the Earth’s crust in forms and quantities that make potential economic extraction feasible. The classification of resources, according to Madani (2020), is significantly influenced by geological confidence and uncertainty, where resources cover the larger mineralizing system that is explored by exploration activities. Resources are generally divided into inferred, indicated, and measured resources, among other classes, according to the level of geological knowledge and confidence.
Mineral resources can be classified into three major classes (Inferred, indicated and measured), which depend on the level of understanding of the geology, reflecting the degree of confidence associated with it. This classification is essential for assessing the economic viability of the mining project, which includes investment risks. To learn more about this classification, get back to one of our articles which title is: How are mineral resources classified?
Mineral reserves
In contrast, this category represents the economically mineable part of the mineral resource. As Bespalov (2022) points out in the discussion of CRIRSCO standards, the reserves should take into account the modifying factors that cover the mining, metallurgical, economic, marketing, legal, environmental, social, and governmental aspects. A schematic diagram from the Nature publication has effectively depicted the relationship as follows: the reserves form a small part of the mineralization, where the darker shades indicate higher confidence in the geological probability of economical extraction (Nature Communications, 2020). The two main types of mineral reserves are probable reserves and proved reserves.
This hierarchy must be well comprehended in order to avoid overestimating exploration projects and to conduct a rigorous analysis of risks in mining investments. The process from resources to reserves is a dynamic process that depends on the progress of technology, prices, and extraction methods.
References
Bespalov, D. (2022). Justification of the CRIRSCO standards and JORC Code for mineral resources and reserves in high-mountain regions. IOP Conference Series: Earth and Environmental Science, 991, 012013. https://doi.org/10.1088/1755-1315/991/1/012013
Fig. 1: Schematic diagram illustrating the relationship between ore reserves, mineral resources, and the true extent of mineralisation within a hypothetical mineral deposit system. | Communications Earth & Environment. (n.d.). Retrieved March 5, 2026, from https://preview-www.nature.com/articles/s43247-020-0011-0/figures/1
Madani, N. (2020). Mineral Resource Classification Based on Uncertainty Measures in Geological Domains. In E. Topal (Ed.), Proceedings of the 28th International Symposium on Mine Planning and Equipment Selection—MPES 2019 (pp. 157–164). Springer International Publishing. https://doi.org/10.1007/978-3-030-33954-8_19
