**1. Introduction**

The main problem of safe coal mining from gas-bearing coal seams is methane contained in the sorbed (bound) state in the system of natural coal cracks. The gas content of methane in dangerous concentrations in coal seams leads to sudden releases of methane, as well as to its explosions and coal dust, leading to catastrophic consequences and numerous deaths. In the main coal-producing countries of the world

(China, United States, Russia, Australia, Ukraine, etc.), the development of highly gas-bearing coal seams is carried out using surface and underground drilling methods as well methods for extracting methane.

However, as the world experience in solving the problems of mine safety shows, the existing technological solutions for the extraction of methane in the development of gas-bearing coal seams are not always effective.

Thus, in [1], a quantitative analysis of the death of personnel in the mines of China for the period from 2006 to 2010 was carried out. Gas accidents account for a significant portion of the death toll in Chinese coal mining has been claimed. The causes of these accidents and the influence of mine ownership on death frequency are considered.

The state of methane safety of coal mines in Russia is constantly considered at the international symposia "Miner's Week." In particular, in [2], the conceptual approaches to the problem of coal mine methane in Russia are considered. It is shown that out of the 105 operating mines, 78% of the mines are dangerous in terms of the maximum methane content, and 45% of the mines are especially dangerous. Kuzbass (Russia) is the main region of the country, where problematic methane-unsafe coal mines are concentrated.

In 2006 and 2007, 256 miners died from coal methane problems due to the lack of reliable degassing systems in Russian mines. At the same time, degassing systems are widely and effectively used in such developed coal-producing countries, as the United States, Australia, etc. In these countries, coal mining with a methane content of more than 9 m<sup>3</sup> /ton is legally prohibited.

Ukraine is one of the countries with the highest (in the world) number of miner's deaths per 1 million ton coal. So, in 2007, in the Donets Basin, at the "Zasiadko" mine, as a result of a gas (methane) explosion, 106 miners and rescuers died. In 2015, methane exploded at the same mine at a depth of 1230 m. Since 1991, 107 people have died in one of the most dangerous in the Donbas mine (the "Sukhodolskaya-Vostochnaya" mine) due to sudden outbursts of methane gas.

According to the authors of this study, the main reason for the mass death of miners is the reluctance of the coal enterprises owners to invest in a direct solution to the problem of methane safety, including the development of new technologies for extracting and capturing methane with its isolated removal to the surface or into mine workings, with dilution to its safe concentrations.
