What if …?

FOOD FOR THOUGHT – 9 August 2021
On a recent trip to Wombeyan Caves, we came upon a couple of disused quarries.  One was a limestone quarry (probably used to make cement), and the other was a marble quarry. I’d not seen cross sections of caves before.  When underground, I don’t imagine how much rock is between me and the surface. At the marble quarry, in a cross section there was a “hole” which started me thinking …

Let’s look at limestone first.  Limestone is formed from accumulated shells, corals, and marine organisms rich in calcium carbonate.  Whilst these reefs were under water, layers of sediment buried the limestone, increasing pressure and temperature over millions of years.  And then the seas receded leaving behind continents with large blocks of limestone mostly underground.

So, what is underground … ?

Here’s Connor sitting on what looks like just a limestone rock (near a hole that we found).

And here’s what it might look like under Connor (after being quarried) we see a cross section, the rock Connor’s on, might be a stand-alone block of limestone like where Heather’s sitting in this image, or a larger piece. Did the dirt around the rock erode before the quarry opened, or did they clear away the dirt to get to the limestone? I don’t imagine this quarry was all that profitable.

Certainly not as profitable as Bungonia, this quarry (currently producing limestone for cement) is HUGE!

And then there’s marble. Marble is a metamorphic rock created through the transformation of limestone or dolostone. This process, called metamorphism, alters the mineral structure and texture of the original rock, producing marble’s characteristic crystalline appearance (thank you Co-pilot search).  Then, temperatures between roughly 300°C and 1200°C and high pressure from tectonic activity or magma cause recrystallization of calcite. Original grains dissolve and reform into larger, interlocking crystals. Geological uplift brings marble closer to the surface, where it can be quarried.  So, to get Marble wounds like there probably has to be some sort of volcanic event.

So here we are at the marble quarry, you can see the difference, white, instead of gray and when you get up close you can eyeball the difference. AND, it’s solid as!

Another section of the quarry. Note how close the marble is to the surface, not much earth there for the tree roots to take hold.

Another part of the quarry. Apparently Wombeyan is known for the high quality of its marble.

Looks like some limestone that hasn’t been used, and in the background is my point of interest.

A small cave, it didn’t go anywhere, was quite small (about 2-3m inside with a 1m opening, no access to the surface above it, just a hole … if the marble hadn’t been mined, we wouldn’t know the hole was there, and the whole of Wombeyan is like this, lots of rocks around, and many holes that could be anywhere (with no access to the surface).

So, what am I ranting on about?  Well, you might remember my post from a few months ago It’s not easy being a farmer these days | Adventures with M – I noted that in NSW areas where there were KNOWN caves, these areas were considered not suitable for the big-arse transmission lines that “they” intended to erect.  You just can’t tell where there are holes under you – or maybe you can with ground penetrating tools – who knows.

So, now let’s look at the Western Green Energy Hub (WGEH) – Clean Energy from Mirning Traditional Lands​ this is a proposed project which will be built in the Nullabor – 3,000 huge wind turbines + solar panels.  As you might know, there are a lot of caves out in South-eastern Western Australia (the Nullabor) – but they’re not like those Wombeyan bomb proof blocks of marble or limestone that’s way underground.

Here’s one of the Nullabor caves, would you put a wind turbine with a rotor diameter ranging from 200 to 275m on ground that has a hole under it like this?  Western Green Energy are proposing 3,000 turbines.  and how do you know there aren’t holes like this without entrances we wouldn’t be able to identify them.

Another cave, lots of breakup above ground, I wonder what it’s like underground?

One of the caves that are obvious (identified by the doline and creek running into it). Not all caves are obvious, and clearly there are caves with no entrances that aren’t in plain sight.

At the base of this cliff (which looks like it would easily fall apart) is the entrance for this cave. 10m of earth between the surface and the very big hole.

They’re going to have to do a lot of ground penetrating research to avoid places like this cave, imagine putting a wind turbine on top of this LOL.

The Green Energy Hub project has been around for a few years now, with no sign that they are going somewhere other than the Nullabor – not that I’m suggesting that they get their eyes on some good solid limestone and marble LOL.  If I didn’t know better, I’d assume this was a Trump “bright idea”!!!

So, watch this space and watch out Western Green Energy Hub!