Struck through coin fragment is a type of error that occurs when a flap of previously coined metal is not ejected from the beating chamber. Simultaneously, another planchet is inserted from the feed arm into the beating chamber, which is struck together with the coin fragment. As a result, the fragment detaches itself from the coin, creating a cavity containing the image of the flap minted in incuse and in an inverted position superimposed on the reliefs partially impressed by the coin.