TY CONF TI RADON FLUX DENSITY FROM SOILS IN THE SURROUNDINGS OF THE LAPICHEVSKAYA COAL MINE KW radon flux density KW radiation safety KW underground mines KW Kuznetsk coal basin JO IV International Conference "Modern aspects of scientific research" AU Fribus, I.V. AU Leshukova, M.K. AU Orozbaev, B.Z. PY 2022 PB AUS PUBLISHERS