Negative-pressure dust removal and micro-mist purification device application in fully-mechanised mining faces with a large mining height

The fully-mechanized mining face is a key site for coal mine dust control. For some fully-mechanized mining faces with a large mining height, the massive amount of fine dust generated by coal-cutting shearer drum and lowering column and moving frame of hydraulic support tends to diffuse to the upper working face and float at high levels. To reduce the pollution at working face, this study innovatively proposed a novel method combining dust extraction at top support beam and pneumatic micro-mist dust removal. Combining the numerical simulation with a three-dimensional high-fidelity solid model and the underground test of the negative-pressure dust removal and micro-mist purification technology, the influence of air volume on the airflow and dust migration and distribution at the working face was analyzed in detail. It was concluded that the floating dust settlement at the working face was the most remarkable when the air volume of the dust collectors was 120 m³/min and their spacing was 35 m. Based on these key parameters, a dust remover integrating powered dust extraction and micro-mist removal was independently developed. An experimental system was established to test the performance of the developed dust remover, revealing that the dust reduction efficiency averaged 98.31% and 95.29% for total dust and respirable dust, respectively. The device was applied to the 22408 fully-mechanized coal face of the Shendong Bulianta coal mine of China Energy Investment Corporation. The field test results showed that the total dust reduction efficiency at the working face exceeded 80% and the respiratory dust reduction efficiency surpassed 70%. The total dust concentration in the respiratory zone of the pedestrian area was reduced to below 15.3 mg/m³,and the respiratory dust concentration became less than 10.3 mg/m³. The proposed dust remover effectively solved the problem of high-level floating dust pollution in the fully-mechanized face with a large mining height and greatly improved its working environment, providing a new way to create a safe, healthy, and green coal mine production environment.