某矿山采空区顶板冒落冲击气流分析及防治措施

Study on Prevention and Control Measures of Impact Airflow Caused by Goaf Roof Caving of a Mine

在空场法采矿过程中,采空区顶板的冒落常会产生较大的冲击气流,严重威胁周围巷道和围岩的稳定性。某矿山的102采场为空场采矿法开采,其采空区顶板岩块的冒落常会产生较大的冲击气流,分析表明,冒落状态较为符合“绕流”气流模型,其顶板岩块冒落过程中空气最大流动速度与冒落体投影面积和冒落高度呈正相关,与采空区面积和空气流动距离呈负相关;采空区岩块冒落最大空气流动速度为0.47 m/s,冒落产生的冲击气流速度为37.77 m/s,基于采场冲击气流速度与安全距离的关系,得到顶板岩块冒落的安全距离为4 m。针对该矿山情况,本研究建议采用尾砂胶结充填采空区的方式,减弱或避免采空区顶板冒落造成的冲击危险。

In the process of open pit mining,the caving of the goaf roof often generates significant impact airflow,seriously threatening the stability of surrounding tunnels and surrounding rocks.The stope 102 of a mine is mined using an open pit mining method.The caving of the roof rock block in the goaf often produces a large impact airflow.Analysis shows that the caving state is more in line with the“flow around”airflow model.The maximum air flow velocity during the caving process of the roof rock block is positively correlated with the projection area and height of the caving body,and negatively correlated with the goaf area and air flow distance;The maximum air flow velocity for rock caving in the goaf is 0.47 m/s,and the impact airflow velocity generated by the caving is 37.77 m/s.Based on the relationship between the impact airflow velocity in the mining area and the safe distance,the safe distance for roof rock caving is 4 m.Based on the situation of the mine,this study suggests using cemented tailing filling to backfill the goaf,in order to reduce or avoid the risk of impact caused by the caving of the goaf roof.