Coast;
That is for actual IFR approaches and not for visuals. Now, I have NO IDEA if Canada requires that visuals retain the same separation standards for runways for visuals as they do the IFR kind. Here south of the border we can go down to REAL close for visuals <G>.
We use the 4200 feet between runway centerlines too. That is what has been found to be safe when trying to keep two aircraft apart on simo approaches when using a standard rotation approach radar system. This gives you enough time to see a pilot blunder into the no transcression zone and then be able to break one of the aircraft out and send them around. With the new PRM (precision runway monitor) radar the US goes down to about half that. The PRM radar is phased array and updates every second. It is VERY good radar and right now it appears that the only hold back to using the procedure is pilot training and reaction speeds...
regards