SUBSTANTIATION OF UNDERGROUND DEGASSING TECHNOLOGY OF COAL SEAM 5 USING THE HYDRAULIC FRACTURING AT CHERTINSKAYA-ZAPADNAYA MINE
To ensure safe mining conditions for extraction pillar #555 when achieving design loads on the faces and complying with the requirements of the “Instructions for the use of ventilation schemes for mining sections of mines with isolated methane removal from the worked out space using gas suction units”, approved by order of the Federal Service for Ecological, Technological and Atomic Supervision dated December 12, 2011 No. 680, it was decided to use hydraulic fracturing technology. In order to intensify gas evolution from the formation before the start of treatment, it is planned to carry out hydraulic fracturing of seam 5 at two test sites in extraction pillar #555, which provides the creation of a system of cracks in a degassed seam oriented to the well and allowing for effective degassing of the coal seam. This article provides a detailed description of hydraulic fracturing testing in the conditions of extraction pillar #555 of the Chertinskaya-Zapadnaya mine. The main objectives of the tests are to determine the effective parameters of hydraulic fracturing, the hydraulic fracturing zone, the initial and residual gas content, the volume and dynamics of methane capture inside and outside the treatment zone, the gas production of the breakage heading outside and in the hydraulic fracturing zone, and the overall degassing efficiency. It was established that the application of the proposed technology will increase the methane yield, mitigate the dynamics of rock pressure of the roof rocks on the development headings and the face of the extraction pillar. A significant increase in the concentration of methane emanating from wells was noted.