It can be hard to measure the flow rates of particles and so mass balances often

need to be carried out using other measurements. A new screen is being tested

and measurements of the particle size were taken. In the feed, $30\%$ passed $1$cm$,$

while in the underflow, $80\%$ passed $1$cm and in the overflow, $10\%$ passed $1$cm$.$

d$)$ What is the mass recovery to the overflow? $(4)$

While some water is added into the crushing circuit, it is not enough to achieve the

desired slurry viscosity for the milling, which is a strong function of the water content.

In the product from the crushing circuit there is already $10\%$ water by mass.

e$)$ How much additional water needs to be added to achieve a solids content of $30\%$

by volume if the solid density is $2\mathrm{.}7?(4)$

The $80\%$ passing size for the mill circuit feed is $0\mathrm{.}8$cm and for the product, it is

$90$m$.$

f$)$ What will the power requirement of the milling circuit be given that the Bond work

index of the material is $15$kWh$/$t$?$