Which one of the following reactions does not occur during extraction of copper?
\( 2\mathrm{FeS} + 3\mathrm{O_2} \longrightarrow 2\mathrm{FeO} + 2\mathrm{SO_2} \)
\( \mathrm{CaO} + \mathrm{SiO_2} \longrightarrow \mathrm{CaSiO_3} \)
\( \mathrm{FeO} + \mathrm{SiO_2} \longrightarrow \mathrm{FeSiO_3} \)
\( 2\mathrm{Cu_2S} + 3\mathrm{O_2} \longrightarrow 2\mathrm{Cu_2O} + 2\mathrm{SO_2} \)