Airflow Law of Goaf with Boundary of Delayed Caving Bolt Supporting Roadways

As the roof can not cave in time in bolt and anchor cable supporting extraction roadway, a goaf flow field with special air leakage boundary along goaf is formed. The finite element numerical simulation method is used, combined with the locale practice of S2-705 working face of Xiaoqing mine, Tiefa Coal Industry Group, the varied characteristics of flow law of goaf air leakage were depicted in theory, and the distributing graph of airflow intensity was given out. It was pointed out that the air leakage boundary along goaf formed without caving is the main boundary that flow into and flow out of goaf from working face, and the air leakage intensity is at the tiptop; the parallel seepage exist in caving non-compacted zone closed to the boundary of working face. The flow trend leads to the gas conglomeration in roadways along goaf at the backward position of return air side, at the same time, two solving approaches, namely dismantling bolt in advance to discharge roof and drainage by auxiliary fan, are put forward. 5figs.,5refs.