Please, I have a mill of volume ~10,000cm3 and I want to calculate the mass of rock sample (-10+5mm) that will occupy 25% of the mill volume. I understand that 25% will be equivalent to 2500cm3. Knowing the density of the rock material to be 2.65g/cm3, I determined the mass of the rock material to use as 6.625kg (mass = density x volume). However, it is seen that the mass is extremely high. I am thinking of multiplying the calculated mass of the rock material by a factor (e.g. interstitial void or porosity). At this stage, I am not very certain I am doing the right thing. Please, I will be glad if someone could assist me. Thank you.