Research on the collaborative faraday technology for open pit caving in the natural caving method of the lower mining belt of Saizijin Mine

The lower mining belt of Saizijin Mine is a thick porphyry copper deposit buried at elevations ranging from −500 m to −2 000 m. The mining method adopted is block caving, with the −780 m level being the undercut stage. Currently, the mine is in the process of extracting the main ore body of the upper zone and the UZ-2 ore body, while the lower zone is under development. Upon the commencement of production in the lower zone, except for a few areas in the northern part that won’t impact the upper zone, the majority of the areas will affect the extraction of the UZ-2 ore body. To address this, during simultaneous production from the UZ-2 ore body and the lower zone, a method using open stope is proposed to locally mine the −780 m undercut of the lower zone while ensuring progress in the lower zone’s undercutting and the overall mine production capacity, without affecting the UZ-2 ore body extraction. The study defines the initial extraction area for the void mining method based on the mining development schedule and the ore quantity at the −780 m undercut. Comparative analyses of the undercutting process using the void mining method after initial extraction are conducted. Analysis and calculations of excavation structural parameters are performed, and a recommended ore column collapse mode is proposed. Discussion revolves around key engineering aspects and the production capacity of the open stoping with subsequent undercutting after initial extraction. The study also delves into potential issues and research directions related to the application of the void mining method after initial extraction using natural caving mining methods.