yes dwarf spot on.
This trap is almost identical to the old Impassable spear or guillotine trap once used in the United Kingdom.
Another trap that is set over and above the mole tunnel this harpoon trap is set after compressing the roof of a shallow tunnel. The trap is then pushed down over the tunnel so that the longer legs straddle the run and the spikes just make contact with the depressed surface. The spikes are then raised to compress the central spring and lock into place.
When the mole enters under the trap and raises the depressed roof the trap is tripped and the spikes are plunged down into the ground and enter through the roof of the tunnel killing the mole.