Copper, Iron and Gold ore do not award experience upon being mined

The Bug:

Copper, Iron and Gold ore do not award experience upon being mined.

Steps to Reproduce:

• Mine some copper, iron and gold ore.
  →  Notice how you did not receive any experience upon doing so.

Information:

This is inconsistent with all of the other ores in the game, so it would make sense if these ore awarded experience upon being mined.