Mining is one of the many valuable gathering professions, capable of harvesting minerals from nodes located around the world. A miner must raise his skill by gathering different qualities of minerals, and can smelt the ore into bars which are commonly used by Blacksmithing and Engineering. These smelted bars are also used as currency to purchase Cataclysm recipes.
A miner must purchase a mining tool and carry it on their person to be able to harvest a mineral node. These mining tools can be quite innovative and double as weapons. Raw, unsmelted ore can also be used in Jewelcrafting for Prospecting, from which jewelcrafters can extract uncommon and rare gems. Ore can be placed in Mammoth Mining Bag, made by Leatherworkers.
In addition, miners can loot Volatiles from Cataclysm nodes; it's generally faster than farming specific mobs. Elementium Geode is a rare BoE pet from Cataclysm nodes as well.
Mining in guild counts towards the achievement Mighty Miners.