An actuation system for a tubular handling mechanism of a tubular handling assembly has a mud flow path passing through rotating parts and non-rotating parts of the tubular handling assembly. A ball drop assembly has an opening to the mud flow path through which a ball is released. The ball drop assembly opening is positioned in a non-rotating part. A lateral passage joins the mud flow path downstream of where the ball is released. A valve is positioned in the mud flow path at the lateral passage for selectively directing a purge fluid from the mud flow path out the lateral passage.