Research and Application of Cemented Filling Method to Sublevel Caving Method Under Soft Broken Rock Mass Condition
Following the instability incident in the upper middle section of the filling stope at the West No.2 mining area of Longshou mine in Jinchuan,the original downward-layered consolidated filling method was replaced with the non-pillar sublevel caving method.To investigate critical technical challenges,such as cover layer formation and stope stability associated with the practical application of this method,numerical simulation techniques were employed for the research.The research findings suggest that as the sublevel stope area within a caving stope expands,the composite roof experiences a sequence of progressive failure stages.These stages include the initiation of failure cracks,dispersed bulk caving,arch batch caving,and plunger integral caving.By the conclusion of the first sublevel mining,the height of the roof collapse is expected to exceed 30 meters,thereby forming a sufficiently thick cover layer for the caving method stope.Concurrently,during the mining process,plastic zones are generated on the surface of the roof along the mining approach.The support structure serves a critical function in anchoring and stabilizing the majority of the plastic zones,thereby contributing to the overall stability of the mining approach.Despite the minimal displacement observed in the access roof,there is a pronounced stress concentration within 5 meters behind the working face,necessitating continued attention.An industrial experiment was subsequently conducted on-site,employing the non-pillar sublevel caving method and utilizing induced caving technology to establish a cover layer.To mitigate the risk of large-scale collapse of the composite roof,a technical strategy involving"stepped mining and uniform expansion of goaf combined with total ore extraction control"was implemented on-site.Microseismic monitoring and on-site tracking data revealed that during the initial sublevel mining phase,the actual caving height of the roof in the mining area surpassed 20 meters,resulting in the formation of a thick cover layer approximately 30 meters thick,inclusive of the reserved ore layer.Throughout the entire mining process,the stope remained in a stable condition.To address the issue of significant damage to the access road in the fractured ore and rock zone,a comprehensive technical scheme incorporating multiple support structures was proposed.For the problem of medium and deep hole damage,a systematic approach involving hole inspection,hole dredging,and hole filling was established.Additionally,relevant equipment was promptly introduced to mitigate operational intensity and enhance the applicability of the non-pillar sublevel caving method under the soft,fractured ore and rock conditions prevalent in the Jinchuan mining area.
non-pillar sublevel cavingcemented fill miningsoft and broken rock masscover layerstability of stopeLongshou mine
万方数据
维普
