A Tunnel under an In-Pit Mine Waste Dump to Improve Environmental and Landscape Recovery of the Site

By adopting the green mining concept, the mining industry seeks to respond to the current societal objective of supplying the mineral raw materials necessary for economic development while minimising the ecological footprint. To accomplish environmental recovery simultaneously with mineral exploitation, as well as to take advantage of mine waste, this study proposes a new solution that includes the construction of a tunnel to access the mining area. The concept, developed with topographical and geological data, was tested for the Bled El Hadba phosphate deposit. The extraction volumes were estimated by considering all the technical and legal aspects of the exploitation. The results showed that the best location for the tunnel is on the non-mineralised bottom of the mine and placed after ore removal. The tunnel is then progressively covered by mine tailings as it is extended. This concept is applicable to sub-horizontal ore deposits. We show that the solution is feasible and allows full site recovery at the end of the open-pit mining phase.