Bleeder entries are critically important to longwall mining for the moving of supplies, personnel, and the dilution of mine air contaminants. By design, these entries must stay open for many years for ventilation. Standing supports in moderate cover bleeder entries were observed, numerically modeled, and instrumented by researchers at the National Institute for Occupational Safety and Health (NIOSH). The measurements of the installed borehole pressure cells (BPCs), standing support load cells and convergence meters, and roof extensometers are presented in this paper in addition to the numerical modeling results and visual observations made by the NIOSH researchers in the bleeder entries. The results include the effects of multiple panels being extracted in close proximity to the instrumented site as well as over one and a half years of aging. As expected, standing supports closer to the longwall gob showed the greatest load and convergence. The roof sag appeared generally independent of the proximity to the longwall gob. The BPC readings were driven by both the proximity to the gob and the depth into the pillar. The results of this study demonstrated that the entry roof can respond independently of the pillar and standing support loading. In addition, the rear abutment stress experienced by this bleeder entry design was minimal. The closer the mine development, pillar, or supports are to the gob, the greater the applied load due to rear abutment stress.

中文翻译：

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长壁矿中的中等覆盖泄放器进入和站立支撑性能：案例研究

泄放入口对于长壁采矿对于供应品、人员的移动和矿井空气污染物的稀释至关重要。根据设计，这些入口必须保持开放多年以进行通风。美国国家职业安全与健康研究所 (NIOSH) 的研究人员观察、数字建模和检测了中度覆盖泄放条目中的站立支撑。除了 NIOSH 研究人员在泄放入口中进行的数值建模结果和视觉观察之外，本文还介绍了已安装的钻孔压力传感器 (BPC)、站立支撑称重传感器和会聚计以及屋顶引伸计的测量结果。结果包括在仪器站点附近提取的多个面板的影响以及超过一年半的老化。正如预期的那样，靠近长壁采空区的站立支撑表现出最大的负载和收敛性。屋顶凹陷的出现通常与长壁采空区的接近程度无关。BPC 读数是由靠近采空区和进入柱子的深度驱动的。这项研究的结果表明，入口屋顶可以独立于支柱和站立支撑载荷作出响应。此外，这种泄放入口设计所承受的后基台应力很小。矿山开发、支柱或支架离采空区越近，由于后桥台应力而施加的载荷越大。BPC 读数是由靠近采空区和进入柱子的深度驱动的。这项研究的结果表明，入口屋顶可以独立于支柱和站立支撑载荷作出响应。此外，这种泄放入口设计所承受的后基台应力很小。矿山开发、支柱或支架离采空区越近，由于后桥台应力而施加的载荷越大。BPC 读数是由靠近采空区和进入柱子的深度驱动的。这项研究的结果表明，入口屋顶可以独立于支柱和站立支撑载荷作出响应。此外，这种泄放入口设计所承受的后基台应力很小。矿山开发、支柱或支架离采空区越近，由于后桥台应力而施加的载荷越大。