The Suitability of Stratiform Ore Deposits for the Narrow Reef Mining Equipment Method: Geological, Morphological, and Economic Criteria

Thin, stratiform ore bodies pose persistent challenges for conventional underground mining due to limited thickness, high ore-grade dilution, and restricted operating space. This study introduces a morphology-based scoring framework for assessing the suitability of ore deposits for the Narrow Reef Mining Equipment method—an ultra-low-profile mechanized technique designed for stoping width up to 1.7 m and inclination up to 22°. A dataset comprising 178 ore deposits/mines was evaluated using integrated geological, morphological, and economic criteria. The results demonstrate that NRE suitability is primarily controlled by ore morphology, which is governed by the genetic model. The highest compatibility is associated with stratiform mineralization formed in layered mafic–ultramafic intrusions (e.g., Bushveld Complex, Great Dyke) and sediment-hosted stratiform copper and gold deposits developed along laterally extensive depositional or redox-controlled interfaces (e.g., Kupferschiefer, Witwatersrand). Although genetic origin defines deposit-scale suitability, secondary geological disturbances—post-genetic tectonism and hydrothermal overprinting—restrict NRE applicability to individual ore bodies within otherwise favourable deposits. By formalizing ore body dip and thickness into standardized efficiency and suitability classes, the proposed scoring system provides a reproducible early-stage geological screening methodology for evaluating NRE applicability during initial mine project development. Economic evaluation based on data from the Unki Mine provides operational validation of the proposed scoring framework and demonstrates that NRE increases monthly output at reduced stoping widths while maintaining ore grades and improving operational safety compared to conventional methods.