Our mines produce Semi Refractory Grade Chrome Ore Lumps too, the specs are as folows: Cr2O3 = 42% min, typ 44% SiO2 = 3.5% min, typ 2.5% Cr:Fe = 2.5:1 min, typ 2.7:1 Al2O3 = 20% max MgO= 22% max P = 0.01% max S = 0.03% max Size: 10mm – 300mm = 95% …