New tower concrete core will rise in April, 7-10 day continuous pour. VCR cab will be built alongside it and hoisted into position by a 90m crane soon after. The whole 61m structure will be up by May2012. Fit out and construction of the low level building then gets underway. Operational late May 2013.
Once the plugs are pulled in the old VCR there is no going back, it will not be a back-up. Contingency arrangements for ATC once the new tower is open are the subject of ongoing consideration.
Apron Control is currently in the 6th Floor of the old tower, and moves to the sub-cab level of the new tower when it opens. A use for the old B Pie Ops Tower is unclear as I write.