Moscow State Mining University (Moscow, Russia):

Dugartsyrenov A. V., Assistant Professor, Candidate of Engineering Sciences, e-mail: fizika@rbcmail.ru

North-Eastern Federal University named after M. K. Ammosov (Yakutsk, Russia):

Markov V. S., Assistant Professor, Candidate of Engineering Sciences, e-mail: marko-valeri@mail.ru

Petrov A. N., Head of a Chair, email: petrov_andrei@mail.ru

The experience of underground mining at the “Internatsionalnyy” mine confirms the principle possibility of increasing the cross-section parameters of stopes, using the layer development system, with the mechanized breaking backfilling, with descending mining plan. Several schemes of purification working were tested on the mine, using the stopes with increased parameters.
The following conclusions were made, according to the calculation results:
1) The vertical pressures у (S22) near the sides are compressing. The degree of these sides is near 32 MPa, which slightly exceeds the ultimate strength of rocks. However, the strength of rocks increases to 2 times, by 106-107 Pa of the side backing. Nevertheless, the possibility of partial failure of sides can not be ruled out.
2) According to the comparison of distribution diagrams of vertical stresses, it is shown that the vertical stresses around the stopes are the same both in the massif and in the backfilling: as in the first case, they account 35-40 MPa. The size of the side backing is also similar for the considered configurations. Taking into account the increasing of rocks strength in the uniform compression, these rocks are in the limiting state.
3) The analysis of stresses around the stope shows, that the most high stope (8 m), with the same wideness (5 m), does not make any noticeable changes into the stress-strain state of massif, which stays the closely compress.
Thereby, the strength of stopes at the “Internatsionalnyy” mine on the depths near 900 m is satisfactory. The following increasing of the stope location depth leads to the less of its stability. The detailed study of elasticity limit, with the registration certificate of the surrounding massif rocks` strength is necessary for more perfect forecast of the stability.

This research work was held with the financial support of the Ministry of Education and Science of Russian Federation, within the project No. 2010-218-01-001 “Creation of complex innovation environmentally safe technology of extraction and processing of diamondiferous ores in the Far North”, which is being held with the participation of North-Eastern Federal University named after M. K. Ammosov and “ALROSA” JSC.

1.Anokhin R. V., Petrov A. N. Gornyy Informatsionno-analiticheskiy Byulleten — Mining Informational and Analytical Bulletin, 2011, No. 2, pp. 11–15.
2. Alekseev A. D., Nedodaev N. V. Predelnoe sostoyanie gornykh porod (The limiting state of rocks). Kiev : Naukova dumka, 1982, 200 p.