Influence of some economic parameters on cutoff grade and ore reserve determination at Itakpe iron ore deposit, North central Nigeria. African Journal of Geography and Regional Planning, [S. l.], v. 7, n. 1, p. 1–6, 2020. Disponível em: https://ijpp.org/journal/index.php/AJGRP/article/view/297. Acesso em: 11 oct. 2025.