Increase of energy efficiency of mine fans work on a mine vent network Tetiana Bunko, Maksym Shyshov, Oleksandr Bokii, Anatolii Belikov, Oleksandr Zhalilov and Ivan Kokoulin E3S Web Conf., 109 (2019) 00012 Published online: 09 July 2019 DOI: 10.1051/e3sconf/201910900012