Mining Institute, Ural Branch, Russian Academy of Sciences, Perm, Russia:

S. S. Andreiko, Head of Laboratory, Professor, Doctor of Engineering Sciences, ssa@mi-perm.ru
N. A. Litvinovskaya, Researcher, Candidate of Engineering Sciences

Saint-Petersburg Mining University, Saint-Petersburg, Russia:

Yu. G. Sirenko, Deputy Pro-Rector of Education and Training, Candidate of Engineering Sciences

Belaruskali, Soligorsk, Belarus:

A. B. Chayanov, Director of Mine Management 1

The article presents findings of the research aimed to develop preventive measures for gas-dynamic phenomena caused in the floor of potash seam III by longwall mining at Belaruskali. The gas content and gas-dynamic characteristics of the potash seam floor rock mass were studied in conveyor, haulage, ventilation and backfill drifts. Boreholes were drilled at intervals and immediately sealed at a distance of 0.5 m from the mouth. Prevention designs were developed based on the result of the mine tests of gas content, gas-dynamic characteristics and time variation of free gas pressure in floor rocks in developing entries under different geotechnical conditions of longwall mining of potash seam III. The mine testing procedure provided quantitative assessment of such gas-dynamic characteristics of floor rocks as: free gas content, initial rate of gas release and free gas pressure. Taking into account the found mechanisms of initiation of gas-dynamic phenomena in mine floor, the methods and designs of preventive degassing drilling were worked out for developing entries in longwalls on the 1^st, 2^nd and 3^rd layers of potash seam III under different geological and geotechnical conditions. The introduction of the preventive degassing drilling in the floor of developing entries in the listed longwalls improves operating safety in mines of Belaruskali.

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