Ural State Mining University, Ekaterinburg, Russia:

Bagazeev V. K., Professor, Doctor of Engineering Sciences
Valiev N. G., Professor, First Pro-Rector
Startsev V. A., Assistant, Vasiliy.Startsev@m.ursmu.ru

The article is representing mining method of thawed argillaceous placer mines by hydraulic drilling mining is. Analysis of hydraulic borehole mining shows that in the formation of the wide area, dumps, roof dislocations and dips of overlying rocks occur. The rocks are set in motion because of the disturbance of the equilibrium state. The ability of rocks to maintain balance when creating outcrops determines their stability. The establishment of the parameters of the extraction blocks with saving the dome of natural equilibrium will allow to overcome the deformations described above. A key principle in the justification of the mining method is the stability of rock outcrops. As a basic mining method of hydraulic drilling mining of thawed placer mines, the single-stall method is considered. Evaluation of the stability parameters of the roof have been carried out, the value of the dome of natural equilibrium has been determined by the calculation method, experimentally, the size of the limiting span has been established. The limiting span - is a span before the collapse of the roof, the main parameter determining the dimensions of the stall. Measurements and observations were carried out on physical models, in production conditions on the "Uvalnoe" and "Visim" mining districts of the artel "Neiva". The comparison of theoretical calculations and experimental data is based on the strength characteristics of argillaceous rocks obtained under laboratory conditions using the generally accepted technique of resistance of a weakly cemented rock to shear and a technique for estimating the strength and compressibility of coarse clastic rocks by DalNIIS. Comparing the results of the research, it is established that the method of Borisenko A. A. is the most suitable for determining the dome of natural equilibrium. The forms and dimensions of the mining stalls are justified, the parameters of which are limited by the dimensions and strength characteristics of the sands and host rocks of placers.

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