OUESTION $2$

$($a$)$ A plant treats $210\mathrm{.}0t$ of material during a shift, assaving $25\%$ metal, to produce a concentrate of $40\%$ metal and a tailing of $0\mathrm{.}20\%$ metal. Copy and complete the table below $[5]$

$\backslash$table$[[$ITEM$,$WEIGHT $/$t$,$ASSAY $\frac{?}{?}\%,\backslash$table$[[$WEIGHT$],[$METAL$/$t$]],\backslash$table$[[$DISTRIBUTION$],[$METAL $/\%]]],[$FEED$,210\mathrm{.}0gar{g}^{2pt},2\mathrm{.}5,-$cdots,$4,100],[$CONCENTRATE$,-126,40,.,\%,-4],[$TAILINGS$,-$dots,$0\mathrm{.}2$:$,,1-.]]$

$($b$)$ A tin concentrator treats a feed containing $1\%Sn$ and three possible combinations of concentrate grade and recovery are;

High grade: $,63\%$ tin at $62\%$ recovery

Medium grade: $,42\%$ tin at $72\%$ recovery

Low grade: $,21\%$ tin at $78\%$ recovery

Determine which of these combinations of grade and recovery produce the highest separation efficiency.

$5$

$[$Total: $10$ Marks$]$