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Seismic impact of technological explosions on underground mining workings of the Magnezitovaya mine was assessed. Seismic stability of rocks of the Magnezitovaya mine was determined and safe distances from technological explosions have been calculated by the admissible seismic effect for rocks. URAN and Minimate Plus seismic recorders with three-component seismic receivers were used to establish the dynamic impact on the mine workings. Based on comparison of calculated values and experimental measurements, the recommendations are given for explosive mass limitation at a slowing-down stage at a level of minimum dangerous values for technological explosions in underground mine. It is established that the blasting operations carried out at the Magnezitovaya mine of PAO Magnezit Combine with fan longhole stopping were performed with the seismic impact safety of underground technological explosion and will not lead to the loss of rock mass stability near the underground workings. Relevance of these studies is to ensure industrial safety of underground mining operations.

The issue of joint production of drilling-and-blasting operations (DBO) is acute in the combined field workings with the condition of underground mining in the edge massif of the pit walls. Normally, the underground mine construction begins with the quarry depth approaching the end marks. In this situation, even if there is any volume for wall cutback, it is very insignificant and blasting works come closely to the limit circuit of the quarry, behind which the protected massif is located and underground workings is supposed to be carried out in the future. The main task in carrying out DBO under such conditions is to maintain the stability of this massif. Timely explosion shielding and the creation of contour fracture surfaces by applying controlled blasting reduce the negative explosion impact on the edge, yet do not always prevent the stress waves spread across the massif caused by seismic effect. Therefore, limiting the explosion seismic action in the border zone is as important for the massif stability as the professional pre-splitting.

The article deals with the links between mineral extraction processes. The most universal characteristic of the process is its energy intensity. Production process cycles are considered in the relationship between their energy characteristics, taking into account the extraction in the working face over time. This approach has been largely determined by earlier studies in the direction of studying the energy intensity of technological processes. However, the relationship between explosive rupture energy and excavation has not been established, although the link between explosive preparation and the performance of the excavation equipment was stated in the technical literature multiple times. The presented material analyzed previously published materials on establishing relationships between drilling and explosive rupture processes of rock massif. The energy characteristics of excavation works and explosive rupture were considered. Prospective direction of technological links study was proposed. Attention is drawn to the fact that the approach to relationships definition between processes may not always be monotonous, because it is sometimes difficult to express physical meaning in a flat system.

As the depth of mining increases, attention to the preservation of mine workings and mining blasting is steadily growing. Technological methods of effective mineral development are often limited by dynamic blasting impact causing short-period fluctuations in the rock mass. Therefore, correct explosion impact identification, to a great extent, determines effective mining trends. Some results of researches for minimum blasting impact on mining workings are given in the article. Calculation of safe distances and excess pressure at shock air impact of technological explosions on the Magnezitovaya mine personnel was made. The calculation was made for the 15.5 m mine working section, with two conditions of the total section of the mine workings adjacent to the face of 15.5 m and 31 m with distances of 50 m and 100 m. Overpressure was also calculated for a total cross-section of 15.5 m and distances of 150 and 200 m. It was determined that the safe distance for people under overpressure conditions at the shock air wave front, depending on breaking schemes, is in the range of 150-200 m. The urgency of this research is to ensure industrial safety of underground mining operations.

The combined mining under the condition of underground mining in the aquifer rock mass of the open-pit sides raises an acute issue of joint drill-and-blast works (D&B). The construction of an underground mine begins normally with the approach of the open-pit mine depth to the final marks. In this situation, if there is a volume for the cutback, it is very small, and the blast works come close to the limit open-pit contour, behind which the protected rock mass is located and in the future the underground mining is supposed to be carried out. The main task in the drill-and-blast works under such conditions is to preserve the stability of this rock mass. The well-timed shielding of the blast and creating the fracture surfaces by the trim blasting reduce the negative impact of the blast on the open-pit side, but do not always prevent the propagation of stress waves caused by the seismic effect along the rock mass. Therefore, restriction of the seismic effect of blast in the border zone is as important for the stability of the rock mass as professional deviated contour holes.

The article deals with the question of the effect of explosive characteristics of emulsion explosives on the shotpile width. Currently, there are two main points of view to select an efficient type of explosive, which contributes to the qualitative destruction (fragmentation) of coarse clastic rocks. The first is based on the assumption that the detonation velocity of explosives must correspond to the break-down point of the rock (dynamic compression). Another point of view is that the detonation pressure of explosives determines only the head part of the pulse, on which the rock fragmentation is dependent only near the charge, in the contact zone around the borehole. The fragmentation of the entire rock volume within a given borehole array depends on the total magnitude of the explosion pulse, determined not by the detonation velocity, but by the total energy reserve of the explosive charge. Experimental explosions with some of the most common industrial explosives have been carried out in the current conditions of blasting of borehole charges by various types of industrial explosives from the point of view to select the most important parameter, which determines its influence on the shotpile width The investigations have been carried out according to the data obtained to establish that the energy properties of explosives (heat of explosive transformation and density of explosives) determine the decisive influence on the shotpile width, and the operability, the volume of the released gases, the detonation velocity for the change in the shotpile width have very little effect and may not be taken into account in calculations for the prediction of the shotpile.

The paper desribes the results of the analysis of the drilling and blasting index at some large enterprises. The significant period of their work has been considered. The increase in the specific consumption of explosives by years has been shown and the reasons for this increase have been explained. The issue of the development prospects of the drilling and blasting complex in terms of reducing the cost of explosives, as well as some issues associated with the use of explosives, manufactured on site. It is suggested that in the near future the development of open mining will be associated with the acceleration of processes and a significant increase in their intensity, both in the development of new ones and in the refinement of existing large open-pit mines. In this regard, drilling and blasting operations are waiting for certain changes in both the mechanization of processes and the technological methods of production. An approach is proposed for improving energy efficiency and resource saving in the production of drilling and blasting operations, which consists in applying a horizontal cut along the bottom of the bench with blasting breaking of the rock mass. It has been previously shown that the use of this method of breaking can be quite effective in comparison with the traditional approach.