Lost Axe Head

Lost Axe Head is a random event that can occur during Mining. The player's Pickaxe splits, causing the Pickaxe head to fly off. The head will land somewhere nearby, usually 3 to 10 squares away. When this happens, the player has to find the pickaxe head quickly before someone else sees it and grabs it. When the player has found the pickaxe head, he/she can use it with their handle to put the pickaxe back together. If a player happens to be wielding the pickaxe when it falls apart, it is possible to use the pickaxe handle as a weapon. Before the addition of the quest What Lies Below, players couldn't re-equip a Pickaxe handle if they had accidentally un-equipped it, but Jagex has now added a Wield Option to Pickaxe handles

Trivia
This random event used to apply to Woodcutting as well, until July 2007, when the event was removed. During this change, all axe handles were removed, and all axe heads were given handles. In the article Behind The Scenes February, Jagex stated the lost axe head will soon be gone forever because the lost axe head random event will be removed from the game