The Proceedings of the Society of Antiquaries of Scotland 1 (1852), page 121 reports the discovery of an iron object inside a lump of coal on 13 December 1852. It apparently resembled the bit of a coal drill and it was suspected that this was the explanation for its presence. As the surface of the coal showed no signs of drilling, though, it was difficult to account for the object in this way.
It is obvious that the initial explanation must be correct: the object was a piece of a broken miner’s drill bit. The coal must have been broken to reveal it, so the discoverer’s apparent certainty that there were no holes in the lump must be regarded with suspicion. Again, this is a nineteenth-century anecdote about a puzzle for which inadequate documentation exists and for which there is no evidence of a thorough investigation of the type that would satisfy a modern archaeologist.