The result of an explosion in fractured rock depends on its degree of fracturing, which can be characterized by the fractional composition of lump sizes in the massif. Fractured massifs are usually classified into very large-block, large-block, medium-block and small-block. In order to predict the sustainable results of the mining, it is necessary to know the category of fracturing of the massif.

The shortcomings of the applied methodology of design thermal calculation of duct heaters are noted, it is shown that the replacement of the heat transfer coefficient of the plant with the heat transfer coefficient of the duct heaters can lead to an inadmissible underestimation of the required heating surface of the plant, which in extreme operating conditions will inevitably cause its freezing and failure.

The following system of differential equations was proposed to calculate the parameters of steady-state air flow through a sealed horizontal air duct.

In a one-dimensional problem for determining the parameters of air during its movement through the pipeline can be taken the following system of differential equations.

In practice, two main methods of mechanized charging of wells are known: from the wellhead and from the bottom hole. With increasing depth of development at quarries the number of watered wells is increasing, which significantly changes the technology of charging wells with hot pouring water-filled explosives (HLWFE).

It is known that at the vast majority of mines and mines located in areas with harsh climate, in winter time part of the atmospheric air supplied to underground workings for their ventilation is heated. To do this at the shafts and adits, where the ventilation jet comes, build, as a rule, steam caloriferous installations with a multi-row arrangement of metal plate calorifiers, the sequential movement of heated air in them provides the necessary air temperature difference...

In the work of L. P. Severin and K. A. Dolgov the formula is given...

It is known that in the near zone of the explosion is spent a significant part of the energy of the explosive charge. Determination and calculation of energy expenditure in this zone are important because they make it possible to control the action of the explosion. In this paper, two methods of determining the energy expenditure are considered - calorimetric and computational-experimental. The calorimetric method considered here, in contrast to the existing ones, is developed for rocks and makes it possible to determine the energy expenditure for the formation of the free surface and to estimate the energy expenditure in the near zone (plastic deformation zone). The computational-experimental method is based on the determination of shock compressibility of rocks and requires the use of relatively complex equipment, either a high-speed photoregister to determine the speed of propagation of the shock wave, or piezometric sensors and cathode oscilloscopes to measure high pressures ...