The Comet closed in 1987 when Lincoln Park shut down for good. The coaster's remained standing, left to the elements, for over 20 years now. The lift hill collapsed several years ago and the trains were taken out of the coaster structure for use at another park (which I thought had plans to resurrect the entire Comet design at one point, but it never came to be.)
I last visited the coaster site back in August with Joye and it was pretty clear then that coaster structure didn't have much longer to live on its own, anyway. Shame nobody stepped up to take care of it back when it could've been saved, but back then this whole coaster preservation thing was new and unfamiliar territory (Knoebels and the former Wild World had both moved existing wooden coasters by 1987, at least, but those were the major exceptions.)
Ah well. In a way I'm glad nature's doing the job on the Comet and not a developer's bulldozer making way for crappy condos or something.