The Exploding rock random event (AKA: "smoking rock" or "gas") was a random event in which a player tried to mine a rock after the point at which it began to "steam/smoke/bubble". After mining that rock for more than a few more seconds, the rock would explode, causing the player's Pickaxe to explode, (see Broken pickaxe) making it unusable. It would also damage the player for a number of Life Points (based on the player's Constitution level) and it could even kill them if their Life Points were already greatly reduced.
Even if the rock was still smoking, and a player had already caused the explosion, there was still a chance that it could explode again, if the player tried to mine it multiple times.
Pickaxes could have been fixed by Nurmof in the dwarven mines and at Bob's Brilliant Axes in south Lumbridge as well as at the battleaxe shop in Port Sarim. There was no charge for Bronze, Iron and Steel pickaxe repairs, but there was an escalating fee for pickaxes made of Mithril and above (it should be noted, however, that at the time that this Random Event existed, the Dragon pickaxe did not). Note that only damaged pickaxes could be repaired. A pickaxe without its head or handle could not be fixed by the NPCs. To remedy this situation, you had to use the Pickaxe handle (not to be confused with an Axe handle) on the pickaxe head to fix it.
This random event was created to ward off macroers by Jagex. It was one of the many counter-bot measures they have placed on activities that require many hours of work, such as Fishing and Woodcutting.
- Due to this event being discontinued, the broken Adamant pickaxe (Named "Broken pickaxe.", including the period) found in the inaccessible part of the temple in Marimbo examine text was changed to "Useless.". Now, it is has been replaced by an undamaged Bronze pickaxe.