Can you use get distance on an activator and make a mine? I want to spam 10 proxy grenades that after 60 seconds explode on their own and remove themselves from the game.

I can make it using an activator and palceatme proxy grenades and 60 sec timer grenades but no matter how the destruction data is set the proxy grenades will not explode unless something goes near them, I need them to remove themselfs after 60 seconds....