Gravel and boulders mining from mountain stream beds Artur Radecki-Pawlik, Anna Kidová, Milan Lehotsky, Miloš Rusnák, Russell Manson and Bartosz Radecki-Pawlik E3S Web Conf., 106 (2019) 01005 Published online: 24 June 2019 DOI: 10.1051/e3sconf/201910601005