Coal and other mineral resources are also commonly found in bauxite mining. The process of bauxite mining is usually affected by retained ore pillars in other strata, which leads to the formation of combinations composed of different strata. Once these combinations become unstable, they can cause serious disasters that threaten production safety. Aiming at the safe mining of co-associated resources in the overlying coal seams of bauxite mines, in this paper, the strength, fracture development, and energy evolution of the coal-rock-aluminum (C-R-A) combination under varying thickness proportions of coal, rock, and aluminum were studied by means of particle flow code (PFC) numerical simulation, SPSS statistical analysis, and other methods. The results indicate that the strength of the combination is significantly negatively correlated with the thickness of the soft coal seam and remarkably positively correlated with the thickness of the hard aluminum layer. Under the same stress conditions, fractures in the combination mainly occur in the coal seam. As the thickness proportion of the coal seam in the overall structure increases, the number of fractures there grows correspondingly. Under a larger thickness proportion of the rock stratum, the combination releases its elastic energy faster after instability, and the fractures develop more intensely. As the thickness proportion of the rock stratum decreases, the elastic energy index (WET) in the C-R-A combination rises, and the burst proneness strengthens. Areas where the thickness proportions of coal, rock, and aluminum lie in the ranges of 30%–60%, 10%–20%, and 30%–60% respectively are considered high-risk zones, and rock burst accidents are most likely to occur when the thickness ratio of coal, rock, and aluminum is 4: 1: 5. These research findings can provide guidance for the safe mining of similar coal and aluminum associated resources.

中文翻译：

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矿柱组合的能量释放及致灾机理


煤炭和其他矿产资源也常见于铝土矿开采中。铝土矿开采过程通常会受到其他地层中残余矿柱的影响，从而导致形成由不同地层组成的组合。一旦这些组合变得不稳定，它们就会造成严重的灾难，威胁生产安全。针对铝土矿上覆煤层共伴生资源的安全开采，本文采用颗粒流码 （PFC） 数值模拟、SPSS 统计分析等方法，研究了煤、岩、铝不同厚度比例下煤岩铝 （C-R-A） 组合的强度、裂缝发育和能量演变。结果表明：组合强度与软煤层厚度呈显著负相关，与硬铝层厚度呈显著正相关;在相同应力条件下，组合中的裂缝主要发生在煤层中。随着煤层厚度在整体结构中比例的增加，那里的裂缝数量也相应增加。在较大厚度比例的岩层下，组合在失稳后释放其弹性能更快，裂缝发展更强烈。随着岩层厚度比例的减小，C-R-A 组合中的弹性能指数 （WET） 上升，爆裂倾向增强。 煤、岩石、铝的厚度比例分别在 30%–60%、10%–20% 和 30%–60% 的区域被认为是高风险区，当煤、岩石和铝的厚度比为 4：1：5 时，最容易发生岩爆事故。这些研究结果可为同类煤铝伴生资源的安全开采提供指导。