Analysis On Mining Technology For Extremely Steep Fractured Unstable Thin Orebody In Phoenix-Hill Sliver Mine

Due to the complexity and difficulties in mining the extremely steep fractured unstable thin ore body, Study has been done on the mining technology for I-â‘ ,I-â‘¡ore body of Phoenix Hill Silver Mine, through site survey,theoretical analysis,numerical simulation and local industrial experiments. Mining scheme adopted shallow rock blasting to achieve non-pillar continuous sublevel open-stop mining was proposed, combining the continuous mining idea and the stage room mining method with sublevel open-stop.The main research work are as follows:(1) Researches have been done on the three common mining methods at home and abroad for the extremely steep fractured unstable thin ore body, and the comparison of advantages and disadvantages of these methods had also been made. Through field investigation and research, the essential reason of the loss and dilution adopting the traditional shrinkage stoping method in Phoenix Hill Silver Mine has been revealed.(2) According to the present technical equipment level and I-â‘ ,I-â‘¡ore body occurrence conditions in Phoenix Hill Silver Mine, Mining scheme adopted shallow rock blasting to achieve non-pillar continuous sublevel open-stop mining was proposed. This method could solve the dilution and loss problems produced by the traditional methods in mining this type mines, through continuous advancing with no pillar forced ore extraction and removal and making use of natural roof wall-rock caving to treat goaf, which provided a new approach for small and medium-sized mine in our country to mining the extremely steep fractured unstable thin ore body in a efficient and low power way.(3) The hole nets and blasting parameters during the extraction process were designed.blasting thrown distance has been examined theoretically adopting volume balance method and energy conservation experience estimation.(4) The geo-stress distribution of the Phoenix Silver stope was researched by using FLAC-3D numerical simulation software, the regions where possibly appeared in-situ stress concentration and large displacement plastic damage were forecasted, and suggestion has been put forward about Underground pressure management according to the simulation forecast result.(5) Local industrial experiments have been conducted adopting the new mining technique in Phoenix Sliver mine for almost one year. Through the field feedback, the stope structure parameters, the blasting parameters and construction schedule have been optimized, and the mining technology and its adaptability have also been promoted.