Aquifers

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This is a section of the cover sequence with the new decline plan.
We’ve been told the decline is now halfway round the 3rd spiral, that puts that position into the middle aquifer, it’s that green layer called the lower sandstones.
The water from this is usable only slightly saline, so will still need disposing to the surface ponds.
Below this level is the lower siltstones, looks as though the ground stability is good.
Below that the brown layer is the lower tillite, a hypersaline water content.
This is unusable and will be placed in a separate evaporation pond, this pond was due to start construction about now.
During the Decline construction the water content has found to be on the lower P10 estimates

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These 2 images are images from the Environmental report.
They show all the drills that were from pads in the SW which caused a lot of bewilderment when no results were issued.
They were drilled looking for the water contents for the decline construction.
The water contents are classed as high P90 and low P10.
You can see the accumulation in that section through the cover strata

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2 images here one poor quality with my notes on it.
The blue graph line is the water content estimates P90 high P10 low
This was drawn before the box cut started.
The bottom line is the months from box cut start.
The vertical line is the water quantity.
From this you can see when they expected to go through the different layers and operations.
You can spot when the vent work was to be carried out.
The soft ground I think from this plan has put us around 4 months back but the decline change has reduced this slightly.
The water content has found to be closer to the P10 levels.
Which has altered the evaporation pond design.
The light brown graph line I think is estimated middle aquifer water content
The dark brown colour is the hypersaline so they look to be not expecting a high water content in the lower aquifer but it is unusable water and needs to be environmentally disposed of in its own evaporation pond which was due to start about now

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This image shows the direction of underground water movements
A lot comes from the salt flats near Teach

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From the 2 satellite images you can clearly see where the current evaporation pond is positioned.
A totally different design to what was planned as you can see in the other image.
Whether there will be anymore we will have to wait and see

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Original pond layout