Current methods and possibilities to determine the variability of Cu content in the copper ore on a conveyor belt in one of KGHM Polska Miedz S.A. minesLeszek Jurdziak, Witold Kawalec and Robert KrolE3S Web Conf., 8 (2016) 01055DOI: https://doi.org/10.1051/e3sconf/20160801055