Preface. The XIV International Research and Practice Conference “Ukrainian School of Mining Engineering” (USME 2020)Gennadiy Pivnyak, Volodymyr Bondarenko, Iryna Kovalevska, Roman Lysenko and Olha MalovaE3S Web Conf., 201 (2020) 00001DOI: https://doi.org/10.1051/e3sconf/202020100001