Safe mining technology of undersea metal mine
(1. School of Resources and Safety Engineering, Central South University, Changsha 410083, China;
2. Hunan Key Laboratory of Resources Exploitation and Hazard Control for Deep Metal Mines Central South University, Changsha 410083, China)
2. Hunan Key Laboratory of Resources Exploitation and Hazard Control for Deep Metal Mines Central South University, Changsha 410083, China)
Abstract: Xinli district of Sanshandao Gold Mine is the first subsea metal mine in China. To achieve 6 kt/d production capacity under the premise of safe mining, high-intensity mining might destroy the in-situ stress filed and the stability of rockmass. According to sampling and testing of ore-rock and backfill and in-situ stress field measurement, safety factor method calculation model based on stress-strain strength reduction at arbitrary points and Mohr-Coulomb yield criterion was established and limit displacement subsidence values under the safety factor of different limit stoping steps were calculated. The results from three years in-situ mining and strata movement monitoring using multi-point displacements meter showed that the lower settlement frame stope hierarchical level filling mining method, mining sequence are reasonable and rockmass stability evaluation using safety factor method, in-situ real-time monitoring can provide the technical foundation for the safety of seabed mining.
Key words: subsea bedrock mining; frame stope upward horizontal slicing and filling mining method; safety factor method; multi-point displacement measurement