Mining is one of the three harvesting professions that can be learned in Rift.
Use
Mining allows you to recover metals, some common, some precious, which you will use mainly for the manufacture of weapons and armor, as well as for certain accessories for the artifice.
Learning
Extraction can be learned at the end of the tutorial, at the Divine Landing for the Guardians or at the Ark of the Chosen for the Renegades. You must first learn the Novice skill, which will unlock the skill.
Once Mining is learned, you can now scavenge metals throughout Telara. To make it easier for you to find materials, you can activate a buff, which will show you the locations on the map where you can mine.
Once the buff is activated, look at your minimap, and you may see dots appear on it that tell you what you're looking for.
You will thus find a vein of metal, which you can mine if you have the level.
Transformation
A player practicing Mining can, after having collected his metals, melt them to make ingots. To do this, use a forge:
Choose the Extraction tab, and you will come to the main window. Here, you can choose the metal to transform, and the result.