Not that close really, most airports I worked in UK operate that the landing aircraft not allowed to cross the start of runway(tarmac) before departed airborne. There are places that have a procedure of 'land after departing' where by landing aircraft can even be on same runway as long as pilot happy to provide visual separation. Radar separation is not used landing/departing as you work in a visual environment in VCR, this changes in low vis operations and then becomes dependant upon separation needed to clear Localiser/glide path sensitive area's.