Old Mine Park in Trumbull is appropriately named, being just full of interesting old tungsten mines. These are in the wooded sections of the park, not the manicured area down below, as seen here:
Walk up the trails behind the ballfields and picnic area. Here's one of the bigger mines right along a hiking trail, surrounded by security fencing. The trails are mostly old mining roads, and easy to walk:
The tungsten ore was removed from what were formerly hydrothermal 'veins', and hauled to the processing plant down below where the picnic area is. The ore reportedly was not very good quality.
A bit further up the trail is another of the larger mines. This one goes back another 10 feet or so from the rock face, where you see black shadow in the photo above the water surface.
I used the camera's flash to illuminate the cave and see what it looked like. Hey, anyone see some little heads sticking up out of the water way in the back? They're frogs! On my computer at home I was able to zoom in and count more than a dozen:
Looks like Green Frogs. Give these frogs a puddle anywhere and they will have a party, even as December approaches (by the way, we also heard some Spring Peepers peeping):
The area around that particular hole in the ground was very green, with the rock covered with lichens, ferns, and moss:
Picking through an old mine heap a few feet away, I found these eggs, which I believe are from a Red-Backed Salamander (they would like the moist hole):
In another part of the park, near another mine (I think you are always near a mine at this park) there was a patch of Blue Cohosh berries:
Here's a second mine deep enough to have a security fence:
It's not a big park, but the mines really add interest. Here's a page with some interesting photos of the ore processing facility. Tungsten was mined for use in light bulbs.
As a bonus, this is a Trumbull park that does not ban nonresidents, presumably because they took federal dollars to build the Housatonic Rail Trail that runs through the park.