I wondering why they weren’t drilling more than one hole at a time? Why wait until now to drill into the place the miners were trained to go?
The vibration from drilling more than one hole at a time could cause a collapse.
Heck, one drill can cause a collapse, but there’s no real choice there.
If they weren’t drilling where the miners were trained to go, where were they drilling?!
Did they think they knew where they were - someplace OTHER than where the miners were trained to go?!
There were drilling both of these holes simultaneously. The second hole is much larger than the first, and drilled slower.
Ever been around a drill rig? Ever see how much additional infrastructure stuff is pulled up around drill rigs when they’re drilling a deep hole?
Once you have, you’d know why they’re punching one hole at a time. There’s only so many locations on top of the “likely spots” where the miners would be, and you can probably fit only one drilling operation on that patch of ground.
I’ve paid for 16” diameter irrigation wells as well as 8” domestic wells to be drilled, hung around and helped the drillers the whole way down and out. From my experience, I can tell you that they’re drilling mighty darn fast with that small-bore rig. Shockingly fast, actually.