Cumulative rock handling between 1970 and 2008 is in the order of 26 Mt HGO LGO ore 272 Mt of overburden making a total rock handling of 298 Mt at ore to overburden ratio of 1 10 50 15 10 9 Beneficiation The beneficiation of low-grade rock-phosphate includes crushing grinding and milling followed by conventional froth flotation route