The ruins of the "Canada Portland Cement Co.", are still visible and still accessible after all these years. Apparently this place is a pretty well known "party-hotspot", as there are firepits and graffiti everywhere. There are still painted concrete slabs that used to be the shop floor, and there are steel support beams that have been cut at the base, and they are scattered everywhere, so be careful not to trip on them.
There is an area that has come to be known as "the caves", which looks to be the former boiler room, with a collapsed concrete roof, so I would advise not going inside. Also, it looks pretty scummy, so there's also that...
There is also a pond in what used to be the rear area of the property, but it is now private property and it is posted as such, do not trespass. But the train-tracks run right through the area, so you should be fine if you stick to the train-tracks and cross over the bridge.
From what I've gathered, this plant shut down in the early 50's and was quickly demolished, and a new plant opened up in town (Qwik-Mix) sometime shortly after.