Was there last week, and the place is a mess full of garbage etc.
If I may suggest the other side of the river from the mine, across a decommisioned bridge and a rock slide, easy enough to get through and much nicer.
Better yet hang right about 2-300m past the first bridge (across Squamish river) and follow the trail up the mountain. Really enjoyable run for quite a few km, challenging enough to keep the heart rate up, but not too gnarly.
Enjoy!
Used to be able to get quite a way in, up to another rotted out bridge you had to push your bike across and carry on for a bit after that. Did not go that far this time, but the other trail I mentioned, just over the Squamish river was really worth it.
Thanks for the beta MtB,
I didn't make it all the way up the first trail. I ran out of jam trying to get Big Barta thru the last rocky section. I looped around on the lower section and think I know where it comes out. If I return with a bit more skill and fitness it will make a really nice loop. I saw a bunch more to explore up there as well.