Future of Mining and Geology: Increase in the Use of Cave Mining Methods to Extract Ore Over the Next 30 Years

Abstract

Abstract The mining industry faces a period of increasingly difficult challenges over the next 30 years. The increasing demand for traditional mineral resources will likely continue unabated as developing countries modernize and the transition from fossil fuels to renewable energy sources ramps up. Compounding the challenge will be more rigorous constraints on mining imposed by environmental, social, and corporate governance (ESG) standards and regulations, as well as the progression from open-pit and shallow underground deposits to large, deeper, potentially lower-grade deposits, where underground mass mining methods are the only viable option. The latter change will especially apply to metals that are critical to mass electrification, including the traditionally required metals such as Cu, Ni, Co, Mn, Zn, U, etc. The more expensive-to-produce critical metals, such as Li, rare earths, high-purity alumina, etc., are currently only used in smaller quantities, and thus open-pit mining of these may remain viable until their near-surface resources are depleted. The large-scale mining of Cu, Ni, and Mo in particular will increasingly rely on cave mining methods, as these are the only profitable underground methods capable of yielding the large tonnages necessary to meet global demands, such as raising living standards within developing countries and providing the foundation for mass electrification of modern society, and all at a time when shallow deposits mined by open pit are becoming scarce. The application of cave mining is thus expected to increase in the future for deep mineral deposits with characteristics that are suited to this mining method. However, poor cave mine performance and/or unpredicted rock-mass responses (e.g., mine-induced seismicity) during cave mining can threaten the viability of the mine and will reduce investor confidence in this method. Irrespective of whether mining is of a traditional metal on a very large (mass) scale, or of a presently critical metal that now has lower tonnage requirements, we predict that geology will need to be more comprehensively considered during mine planning and design—right from the early stages of mine study—because of the uncertainties that the host rocks (geology) present to mining. This will be especially important in complying with the ESG constraints that are being applied to mining companies, in addition to the concept of sustainability that they also seek to address. We review—and propose remediation research of—the various geology-related issues that are already causing concern during mass underground mining by caving of Cu ore; some of these issues are equally applicable to other types of mining, such as open-pit and narrow-width extraction.