A recent study conducted by the National Institute for Occupational Safety and Health (NIOSH) evaluated the roof bolter canopy air curtain (CAC) system in a blowing face ventilation system, demonstrating its effectiveness and illustrating the CAC protection zones. This study evaluates the roof bolter machine CAC while operating in an exhausting face ventilation system. This study considers two similar locations to allow comparison with the previous blowing face ventilation (Zheng et al., Min Metal Explor 36(6):1115–1126, (2019)) study: (1) a roof bolter machine bolting the roof at 20 ft (6.1 m) from the face and (2) a roof bolting machine bolting at 4 ft (1.2 m) from the face. The environment introduces 6.0 mg/m3 of respirable dust to represent the roof bolting machine operating downstream of the continuous miner. However, the exhausting face ventilation uses an exhaust curtain with 9000 cfm (4.25 m3/s) of air. Two roof bolter machine working positions are simulated with the use of dual drill heads in the inward position for two inside bolts and in the outward position for two outside bolts. The influence of the CAC on airflows and dust dispersion is evaluated with the CAC operating at 250 cfm (0.12 m3/s) with dust reductions ranging from 39.5 to 82.8%. When the roof bolter machine operated close to the face, increasing CAC airflow was required for adequate protection since the dust reductions can be as low as 39.5%. Additional CAC airflows of 350 cfm (0.17 m3/s) and 450 cfm (0.21 m3/s) were evaluated and demonstrated that dust reductions increased to 59.7% (350 cfm) and 72.0% (450 cfm) for the worst location where the roof bolter operators located.

中文翻译：

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Roof Bolter Canopy Air Curtain 空气幕对使用排气幕通风的入口气流和粉尘扩散的影响

美国国家职业安全与健康研究所 (NIOSH) 最近进行的一项研究评估了吹气面通风系统中的锚杆机顶篷空气幕 (CAC) 系统，证明了其有效性并说明了 CAC 保护区。本研究评估了在排气工作面通风系统中运行时的锚杆机 CAC。本研究考虑了两个相似的位置，以便与之前的吹气面通风进行比较（Zheng 等人，Min Metal Explor 36(6):1115–1126, (2019)）研究：(1) 将屋顶螺栓固定在距工作面 20 ft (6.1 m) 和 (2) 在距工作面 4 ft (1.2 m) 处锚固的顶板锚杆机。环境引入了 6.0 mg/m3 的可吸入粉尘，代表在连采机下游运行的锚杆机。然而，排气面通风使用排气帘，空气流量为 9000 cfm (4.25 m3/s)。使用双钻头模拟两个锚杆机工作位置，两个内部螺栓向内，两个外部螺栓向外。CAC 对气流和粉尘扩散的影响是通过 CAC 在 250 cfm (0.12 m3/s) 下运行，粉尘减少范围为 39.5% 到 82.8% 来评估的。当锚杆机靠近工作面运行时，需要增加 CAC 气流以提供足够的保护，因为粉尘减少量可低至 39.5%。对 350 cfm (0.17 m3/s) 和 450 cfm (0.21 m3/s) 的额外 CAC 气流进行了评估，并证明对于屋顶最恶劣的位置，灰尘减少量增加到 59.7% (350 cfm) 和 72.0% (450 cfm)螺栓操作员位于。