|Release||17 September 2009 (Update)|
|Location||Living Rock Caverns|
|Ore||Coal (133 coins)|
|Max yield||Until despawns|
|A large concentration of coal.|
Concentrated coal rocks are clumps of coal located in the Living Rock Caverns beneath the Dwarven Mines. It requires level 77 Mining to mine, awarding 50 experience per coal mined. There are eight of these rocks in the Caverns. Concentrated coal rocks contain a much larger supply of coal than a normal coal rock, with a chance at receiving two ores at once, until they collapse. The double ore bonus stacks with the bonuses from Varrock armour and the reward from the Shooting Star Distraction and Diversion, potentially resulting in a bonus of four ore at once. Gems cannot be obtained from this type of rock. A coal bag can be used to store up to 81 coal.
After a random time interval the concentrated coal rock will collapse and cannot be mined from until it replenishes itself, which is also random. Therefore no competition exists for resources when mining from concentrated coal rocks.
The rocks are guarded by the creatures of the Living Rock Caverns, the living rock protectors, living rock strikers, and living rock patriarch. These monsters are aggressive and pose a threat to any players mining from the concentrated rocks, so it is generally advised to mine on world 84, the official world for the Living Rock Caverns. Multitudes of players mine and fish in the Living Rock Caverns on this world, lessening an individual player's chance of coming under attack. However the extremely high volume of players on this world may make lag an issue for players with lower-performance computers. Alternately, a magic golem outfit or a complete set of any shark outfit will render the creatures docile, allowing players to use any world.