(A) $(i)$ Extraction of copper from $Cu_{2}O$: In the Ellingham diagram,the $Cu_{2}O$ line is at the top,making it easy to reduce copper oxide ores to metal by heating with coke. Often,sulphide ores are roasted to oxides: $2Cu_{2}S + 3O_{2} \rightarrow 2Cu_{2}O + 2SO_{2}$. The oxide is then reduced: $Cu_{2}O + C \rightarrow 2Cu + CO$. In practice,iron is removed as slag $(FeSiO_{3})$ and copper is obtained via auto-reduction: $2Cu_{2}O + Cu_{2}S \rightarrow 6Cu + SO_{2}$. The product is called Blister Copper.
$(ii)$ Extraction of zinc from $ZnO$: Zinc oxide is reduced using coke at high temperatures $(1673 \ K)$. The oxide is mixed with coke and clay to form briquettes: $ZnO + C \xrightarrow{1673 \ K} Zn + CO$. The zinc metal is then distilled off and collected by rapid chilling.