How do miners know when a stone quarry is fully tapped out?
I was using Google Maps – street view – to look at some quarries:
example 1
You can see how the road spirals down the the bottom.
It seems like they’re leaving a huge amount of rock on the sides of the quarry. Why? How do they decide when to stop digging?
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6 Answers
A stone quarry mines rock. It is obvious when the rock is gone, which is almost never. A rock quarry will also crush rock for gravel. The mine may close because the water table is too high, or quarrying at higher levels closer to ground level, for example, is more cost effective.
The pit you describe sounds more like a large open pit copper mine that mines copper ore. When the ore is gone (or for other reasons) the mine closes.
@kritiper no, that is a gravel pit about 15 miles from where I live – no copper.
@elbanditoroso OK, so it is a gravel pit. They will quit using it when the diameter of the hole exceeds the area of the property/claim, or the sides of the hole cannot support said sides and begin to cave in, or the water table becomes too much to deal with. Or developments surrounding the pit get to the point where they don’t like the dust, noise, trucks, etc., and force the pit to move.
^^^ All of the above, plus when the expense of the work exceeds the revenue.
Gravel pits will be around forever, since the sand and gravel is always needed. Gravel pits are usually in (old) river beds, whereas rock quarries can be wherever the desired large rock/boulders are found to quarry.
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