The Navy has released more information on the mine that was discovered floating in the Puget Sound earlier this week. A press release said that they conducted additional analysis on Tuesday’s incident involving an unknown mine in the Puget Sound and subsequent detonation at 8 p.m.

It was determined the mine was from an exercise Naval Undersea Warfare Command, Keyport conducted in 2005. This exercise was an opportunity for academia to demonstrate various Unmanned Underwater Vehicles and their capability to detect underwater objects and avoid submerged obstacles.

During this exercise, inert training mines were placed in areas between Brownsville, Keyport, and Bainbridge Island. Only a small number of the training mines were positively buoyant. Not all training mines were recovered.

It has been confirmed the device destroyed Tuesday was a positively buoyant, inert training mine used during the 2005 exercise.

In order to avoid similar incidents in the future, the Navy will survey the exercise areas and recover any remaining positively buoyant mines.