If I remember correctly, when the Canadian Government returned Harvey Barracks in Calgary to the Sarcee Nation, it cost approx one million dollars per square meter to clear the land of explosives down to a depth of six meters or something to that effect.
All our current major Bases, including Borden, have been used for Artillery and Armour Ranges, some dating back over one hundred years. To clear those Ranges would put the Government into such a huge Deficit that we would never recover.
On another point, the Ranges in Gagetown are considered a 'nuisance' to the populations of St John and Fredericton when Tanks and Artillery are firing. The same is said in Petawawa, and it is a Rural area. When Night Illumination is used, the reports of UFOs are rampant. Would the populations of a larger metropolitan area put up with this? Most likely not.