SLC-3W
SLC-3W was used briefly by SpaceX during the early development of the Falcon 1 launch vehicle.
Several test firings of the Falcon 1 were accomplished before SpaceX discovered that due to the overflight risk they would not be allowed to launch from SLC-3W while launch vehicles were standing on adjacent launch sites. As one of the adjacent sites was at the time occupied by a "pad queen" (a launch vehicle that sits on its launch pad for months or years before launch) the restriction caused SpaceX to abandon SLC-3W and instead develop their Omelek Island launch site for Falcon 1. SpaceX co-founder Elon Musk has stated that no compensation was paid to SpaceX over this issue.
It was announced in mid 2010 that from mid 2012 SpaceX is to use SLC-4 for Falcon 9 launches from Vandenberg.
SpaceX announced in April 2011 that they would launch the first flight of Falcon Heavy from Vandenberg, anticipated in 2013.
Read more about this topic: Vandenberg AFB Space Launch Complex 3