Four hundred meters below here lies a coal seam. In this little clearing in the middle of the forest you will find a station that monitors the water pressure in the ground above the coal seam. There are quite a few of these hidden away in the bush around these parts.
In this particular borehole there are two pressure sensors - one at 320m below ground level and the other at 95m. The borehole is then filled with a cement mix to 'seal in' the pressure.
It takes several weeks to drill to depth, a careful analysis of the strata through which the borehole passes, particular care to place the pressure sensors in a zone that gives the information that is required, and, finally, to fill the borehole with the cement grout. It is hot, dusty, and slow work. Once the installation is complete, the site is remediated to protect it from the ravages of dirtbikers and 4wds, and to encourage regeneration of the bush.
NOTE: There is nothing of value in the monitoring station, except the information it gathers. Please leave it alone and do not damage it.
A short walk through the bush from this borehole is the cache. It's a simple, straightforward cache placed to bring you to an interesting location that is not boring at all.
Take a look at the rock around you and let's have a little 'earthcache' like moment.
At your feet is a soft sandy layer. It is eroding quite quickly. There is no water running down this rock and so the mechanism that causes the erosion is wind. Take a look at the smooth curve and the paper thin crust on the surface. It is very fragile so please don't damage it.
At about knee level is a conglomorate layer. Check out the little quartz 'pearls' embedded in the layer.
Keep moving your eyes upward. You'll notice several different types of layer - some strong and homogenous and some quite fragile. How many can you identify?
On the very top layer (above your head) you will notice Lichen growing on the rock surface. This material is strong and stable. Unlike the sandy layers below it, it is stable enough to allow the lichen to take hold. Walk around to the top of this rock if you have the time. You will see some serious folding in the rock, and foliation where the rock is breaking apart layer by layer.
WARNING: There is plenty of loose rock in this area - under your feet and over your head - so please be careful.
Not interested in rocks? Take a look around you at the plant life. This area was burnt out in 2013 and, when this cache was placed one year later, the trees are shooting new growth. The undergrowth is gone and the forest floor has lots of freshly germinated plants that are growing like crazy to gain a foothold while there is light getting through the canopy.
When visiting this cache, I would love it if you can post a photo of the area showing how forest regeneration and growth is continuing after the man-made and fire-made changes that have taken place here.
In memory of Graeme Crawford - a workmate (and sailing buddy) who laboured with me in the heat and the dust to put the station here. He was diagnosed with cancer not long after this job was finished, and succumbed six months after that. This cache will always remind me of you Crawfs.