The birdcage

timdole · 19 Jul 2013, 10:59 am

So one of my friends up in the blue mountains gave me a tip off to this unusual structure called the birdcage or the convict hole.

Just below the metal cage is a 15m deep hole cut through stone.

This is in the middle of absolutely nowhere, apart from a construction site storage facility nearby there is no man-made structures recent or old. While I have heard stories as to it's existence, I want to know if anybody else knows what it is/why it is here?

dodger · 19 Jul 2013, 11:34 am

I've heard that there's a geocache at the bottom of that hole. Is it really 15 metres deep?

Nuggs · 19 Jul 2013, 11:52 am

Very unique!
Quick research suggests it was used as a grain silo for a nearby dairy.
It is 7m deep, and has a small access tunnel at the bottom.

timdole · 19 Jul 2013, 11:59 am

There was a geocache, idk if it's still there. That's what I found on the internet about it being an old grain silo, just wanted to know if others had heard the same thing/something different. As for depth, a dropped rock took just under 1.5 seconds to hit the bottom, so (bare with me) gravity is 9.8m/s/s.
9.8 x 1 x 1 + 9.8 x 2 x .4 = 17.6m, it's a deep hole.

Nuggs · 19 Jul 2013, 12:00 pm

There is a geocache there, up the top though

Nuggs · 19 Jul 2013, 12:09 pm

At 1.5s I get about 11m.
Did you enter the bottom?

timdole · 19 Jul 2013, 12:22 pm

My mistake, it has fallen 11m and is falling at a rate close to 15m a second.
Didn't bother, while you can crawl in, the view at the top is much better then the bottom

blakjak · 19 Jul 2013, 3:19 pm

Looks like a dry well to me. How far off the path is it? Good of them to prevernt anything falling in.

timdole · 19 Jul 2013, 4:18 pm

After a 200m bush bash from the road there's the rock wall right in front of you, and you just gotta climb that semi-cliff face. so once you know the way to head it's simple enough.

blakjak · 19 Jul 2013, 4:25 pm

Could it be a vent from a (former) mine shaft?

Aydun · 19 Jul 2013, 4:28 pm

Tie camera (video) to rope and lower into hole

Never mind, just noticed you'd been down the bottom!

timdole · 19 Jul 2013, 4:44 pm

Potentially a failed mine shaft, as at the bottom it's solid rock (ie it's just a hole, no connecting tunnels). Though what what would you hope to find mineing through such hard rock ..? maybe gold?