ASSESSMENT OF THE POSSIBILITY OF APPEARING OF GAS-DYNAMIC PHENOMENA ON THE II POTASH HORIZON OF THE STAROBINSKY POTASH SALT DEPOSIT

Abstract

The relevance of the study is dictated by the need to ensure the safety of mining operations and at the same time to minimize the monetary and time costs of degassing sole and roof rocks. Having assessed the possibility of the appearing of a gas dynamic phenomenon depending on different conditions of mining, it is possible to identify those areas where special measures are really required to prevent gas dynamic phenomena. This kind of division of the productive formation into sections according to the danger of appearing of gas dynamic phenomena allows a differentiated approach to ensuring the safety of mining operations without unnecessary financial costs. Objective: to assess the possibility of the appearing of gas dynamic phenomena from the sole and roof rocks of mine workings in various mining and technological conditions during the development of reserves of the II potash horizon; form recommendations for mining operations in places where it is possible to develop gas dynamic phenomena. Object: free gases of clay contacts of the II potash horizon. The research method consists in comparing the pressure of free gas in the rock mass with the bearing capacity of the rock layer between the center of the gas dynamic phenomenon and the roof/sole of the mine. The method takes into account the width of the workings, the distance from the roof /sole to the accumulation of free gas, the pressure of free gas, the strength properties of rocks, the geostatic component. Results. The assessment of the possibility of appearing of gas dynamic phenomena is made in both types of mine workings, with a roof span of 3,2 m, and in places of extensions where the roof span reached 6,0 m. During the assessment, it was taken into account whether the area in question was underworked by mine workings below or not. The assessment was carried out for different gas-saturated layers. As a result of the analysis, it was found out that gas dynamic phenomena are not predicted for sole rocks, regardless of the geotechnological situation and the width of the workings. Degassing of sole rocks of advanced workings of the II potash horizon is not required. As a result of the assessment of the possibility of gas-dynamic phenomena appearing from the roof rocks of 3,2 m wide workings, it was shown that gas dynamic phenomena from the roof rocks are not expected and preventive measures for degassing are not required. The assessment of the possibility of gas dynamic phenomena appearing from the roof of the chambers of the U-turn of vehicles showed that in the places of crossing of working, in the extensions of workings, a belated gas dynamic phenomenon from the roof of the mine working is possible. In these places, degassing of roof rocks is necessary. The depth of the degassing boreholes should be at least 2,0 m.

Keywords

• gas dynamic phenomena
• gas content
• gas dynamic characteristics
• potash mine
• conditions for appearing of gas dynamic phenomena