$3\mathrm{.}1$ What are the advantages of wet grinding over dry grinding

$3\mathrm{.}2$ Kumba Iron Ore Limited, a mining company in South Africa, crushed an Iron ore with a feed that is $80\%$ less than $50\mathrm{.}8mm$ in size and a product size which is $80\%$ less than $6\mathrm{.}35mm.$ The power required is $89\mathrm{.}5kW.$ What will be the power required using the same feed for an $80\%$ less than $3\mathrm{.}18mm$ product? Use the Bond equation. $(5)$

Hint: The work index Ei is unknown, but it can be determined using the original experimental data in terms of $T.$ In the equation for the new size, the same unknowns appear. Dividing one equation by the other will eliminate these unknowns.

Given:

$xf1=50\mathrm{.}8mm$

$xp1=6\mathrm{.}35mm$

$P1=89\mathrm{.}5kW$

$xp2=3\mathrm{.}18mm$

Required: P$2=?$