[SyrialKilla]

I would talk to your floor and absolutely give the player a serious warning. Let him know that a muck must be made in the general direction of a muck pile. If he continues to repeat his mucking action I would have him suspended from play in your room for a 24 hours, then a week and then just bann. Someone who defies the integrity of the game or the right for other player to play the cards they are dealt should not be on a game at all.
Just an opinion of course