Predicting the risk of strong mining-induced seismicity based on the rock load/unload response theory

Taking Laohutai Coal Mine in Fushun of northeastern China as an engineering background,an application study of strong mining-induced seismicity prediction was carried out on the basis of the load/unload response ratio(LURR) theory.It is shown that when the load/unload response magnitude adopts the mining-induced seismicity of 0 ≤ M_L ≤ 0.5,the forecasting efficacy is very good in all mining depths and the average forecasting reliability of the staged peak magnitude is 0.72.When M_L ≥ 1.4,the response magnitude is direct proportion to mining depth,and is generally 0.5 to 1.0 lower than the predicted magnitude,while the average forecasting reliability of the staged peak magnitude is 0.60.When 0.6 ≤ M_L<1.4,there might be a mixture of two mining-induced seismicities with different mechanisms,which is not suitable to the load/unload response magnitude due to its wide randomness.With the increase of mining depth,the in-situ stress intensity is higher,and the prediction is better.According to universal tests in Fuxin Coal Field and Mentougou Mine,the forecasting reliability is 0.8 and 0.73,respectively.The results indicate that the LURR theory and methods have a good ability and a broad application in predicting strong mining-induced seismicity.