The influence of extraction speed on the value of the coefficient of subsidence rate

The presented paper discusses the issues of prediction of land surface transient deformation state caused by underground mining, using Budryk-Knothe theory, which is still the most popular solution in this field in Poland. The research results known from the literature and authors' own observations indicate the relationship between the value of the coefficient of subsidence rate “c” and the speed of extraction progress as well as the depth of underground mining works. Firstly in this paper, a short description of present knowledge state in this field has been presented. As the next part of this work, an empirical formula (9) has been proposed, that links the value of parameter “c” with the depth of mining works and the extraction speed. The formula (9) has been worked out on the basis of 9 cases, where extraction was led with the different speed at different depths. Then, the obtained formula was compared with some research results known from the literature. Presented calculations results are consistent with them, concerning analyses of surveys conducted above underground mining extraction carried out with high speed. This allows considering the proposed empirical relationship (9) as valid and useful for the practice of mining in the field of prediction of land surface transient deformation state. In the final part of the paper, some suggestions have been pointed, regarding the further possible development of the research toward increasing the accuracy of predictions of transient deformation state caused by underground mining.