The coal bag was a reward purchasable from the rewards trader for 4,000 Dungeoneering tokens. It required a Mining and Dungeoneering level of 35, however at least level 40 was required to earn the tokens needed for the coal bag, unless you won them through other means such as Sinkholes, Elite Dungeons, or Treasure Hunter. Only one coal bag could be in the player's possession at any time.
The coal bag held up to 81 pieces of coal. When smelting or superheating, coal in the bag would be used before the coal in the inventory. It was refillable just like the rune essence pouch, though it did not degrade.
This item couldn't be traded or dropped but it could be destroyed. The bag had to be empty to be destroyed; otherwise, the player received a notification regarding the coal still left inside the bag. Mined coal was not automatically stored into the bag. Instead, players had to manually use a coal on the bag. When coal in the player's inventory was used on it, all pieces of coal (up to the limit) were deposited into the bag. You could also primary click on the coal bag and select the fill option, which filled it with all coal in your inventory.
Upon player death, the coal bag was completely lost along with any coal inside if it was not kept as one of the three items. This item did not appear under your gravestone.
A fill option to deposit all the coal in your inventory was available while having the bank opened with your coal bag in your inventory.
The coal bag was removed with the release of the reworked Mining and Smithing skills, as the skills' changes made the coal bag unnecessary. Any player who had purchased the coal bag was refunded the Dungeoneering tokens upon logging in after the update.
- Regardless of the amount of coal in the bag, it weighed 0 kg (even though 81 pieces of coal = 183 kg).
- The coal bag used to cost 20,000 Dungeoneering Tokens before the 21 April 2010 update.
- Mod Chris L stated on the "Live Q&A New Skill - Answers" that the coal bag originally only meant to hold 10 coal "but when I went ingame to test it myself after making it, I realized it was a bit rubbish! I ended upon 27 as it meant you could smelt more runite ore per inventory, it worked out nicely".
- Smithing elemental bars takes the same amount of coal and yields the same number of bars as mithril, but only at the furnace of the Elemental Workshop, as no other furnace is hot enough to smelt the elemental ore.
- While bank booths offered the ability to empty the coal bag whilst using the banking interface, bank deposit boxes did not. This meant that you had to exit, empty, and re-enter the bank deposit interface to unload the coal from your coal bag. Alternatively, players could use a piece of coal on the box, select "4: All", empty some coal out of the bag, and repeat.
- Unlike most interactions, attempting to use a random item on the coal bag would not yield the "Nothing interesting happens." dialogue.
- The amount of coal held by the coal bag was increased, from 27 to 81, on 20 July 2015.