Quote: "I would like to see a mine that can be thrown like a grenade and act like proximity for other players"
If I understand what you require correctly one can create a mine like object that will explode in relation to player proximity. It should be possible to also have it explode on proximity to NPC's to though I dont think I ever tested that out so perhaps not in practice.
The same object with amended script or settings should be able to be collected by the player carried in the hand and thrown as a grenade and in this instance "before" exploding on contact with another world object or entity.
If you want to have a grenade type object to throw near NPC's and only explode when they get near that would be very difficult - you might get away with carrying and placing such an object into position though if it does not kill the player first. Force of impact is the key to the possibility.
I have had these things working in the past though I am aware that the source has changed and some things that perhaps once worked now do not. As I dont now work with either the source or the editor/engine at this time I can not advise any further with any certainty.