The operating data for a ball mill is summarized;

a$)$ Express the mill speed as a percentage of the critical speed. $(4)$

b$)$ Calculate the steel ball charge for such an empty mill in tonnes. $(4)$

c$)$ Express the mill pulp density in terms of;

i$.$ Liquid$-$Solid ratio $($dilution ratio$)(3)$

ii$.$ tonnes $\frac{?}{m^3}(3)$

d$)$ Compute the mill feed water addition if mill feed contains $1\mathrm{.}6\%$ moisture. $(4)$

e$)$ Indicate the purpose of mill liners. $(3)$

f$)$ Calculate the rate of ball addition $($balls per hour$)$ if steel balls of diameter $75mm$ are used and

consumption rate being $1\mathrm{.}02k\frac{g}{t}$ of ore. $(4)$

PLEASE ANSWER EVERYTHING $.$ PLEASE.

in i where is the ball radius from?