The article presents brief description and results of laboratory and in-situ tests of frame support with backfilling of behind-anchoring space with grout. Characteristics of mining and geological conditions on the site of inclined conveyor shaft of Sychevskiy-I mine-section, A.D. Ruban Mine (JSC SUEK-Kuzbass) has been given. Grouting quality has been tested according to described technology, strength characteristics of cement and degree of grout mix influence on the surrounding rock mass has been determined. It is figured out that reinforced canvas use as a between-frame overlap increases cement strength. Some recommendations regarding the use of reinforced canvas as a grouting material have been formulated.

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In mining minerals by open-cast method, the environment is exposed to a powerful man-made impact, a significant part of which is associated with mass explosions during rock crushing. In preparation of rocks for excavation by blasting, a significant amount of dust and gases is emitted into the atmosphere; therefore, a decrease in the use of explosives is an urgent task both in terms of reducing the cost of blasting operations and from the ecological point of view. This task can be solved by increasing the effectiveness of the explosion. The results of studies of the process of blasting boreholes with a non-circular cross-section confirm the practical need in developing this drilling tool. In using the kinematic method applied in engineering for assigning complex surfaces, the conditions under which it is possible to produce boreholes with a non-circular cross-section are considered. The designs of the drilling tool with variable and fixed linear dimensions are selected which allow formation of a noncircular cross-section of the borehole, their shortcomings have been analyzed. The roller-cutter method for forming a noncircular cross section is substantiated, at which a smaller number of kinematic links of the drilling tool is achieved and a greater number of ways to impact the rock is ensured. Keywords-rock drilling, kinematic analysis of drilling tools, non-circular shape of a borehole, design of the drilling tool, drilling tool roller

Introduction. The paper analyzes contemporary methods of frame support design in permanent workings and reveals that contact grouting has received little attention. Contact grouting makes the tight contact between the hardened cement grout and the surrounding rock possible, whereas it is impossible when applying concrete lagging. The paper employs analytical method of arch support, grouting layer, and the surrounding rock calculation considering their softening. Analytical formulae determining support load has been obtained. The formulae take into account strain and strength characteristics of the surrounding rock, hardened cement grout, and support. Support load was calculated under various values of the grouting layer thickness and linear strain modulus and the depth of mining. The dependencies between the support load and the indicated parameters have been obtained, which makes it possible to select the cement grout composition for various mining and geological conditions. Research objective is to determine the effect produced by grouting layer thickness and strain characteristics on arch support load value in order to check its strength in various mining and geological conditions. Methods of research are built upon the physically based analytical methods of geomechanics to solve the problem of interaction between the support, grouting layer, and surrounding rock mass. Results. The results of arched support load calculation are presented for various values of grouting layer thickness, its strain characteristics, and depth of mining. Conclusions. The presence of the grouting layer in the void behind the support has a significant effect on the methods of arch support design. The developed methods take account of the fact that a layer of soft rock develops in the rock mass between the grouting layer and undisturbed rock. When the rock is being broken, its volume in this layer increases, which, in its turn, results in support load transfer growth through the grouting layer. It has been determined that the increase in the hardened cement grout strain and grouting layer thickness reduces support load.