Gusaba:Irashobora gukoreshwa mugutunganya amazi - 1,2 mm (- mesh 200 ya 30 ~ 100%) ubutare butukura (hematite na limonite, siderite, nibindi), ubutare bwa manganese, ilmenite, chromite, amabuye ya tungsten nubundi bwoko bwamabuye y'agaciro ya magnetique, n'amabuye y'agaciro, nka quartz, feldspar, ubutare bwa nepheline, kaolin yo gukuraho ibyuma byanduye no kwezwa.