I did the construction globally, from USA to UK to Saudi Arabia.
I'm talking about both sand in construction and in general (like for glassblowing, etc.) Portland cement uses the finest sands possible for holding concrete aggregate, which you only really tend to find in desert areas (if you're lucky enough to find a spot that hasn't been above water for more than a million years, that's one reason construction-grade stuff is so hard to find.)
Now days, I do very similar to your link, except it's through mountains, and terminates inside the mountain. Minerals extraction is fun!
I'm talking about both sand in construction and in general (like for glassblowing, etc.) Portland cement uses the finest sands possible for holding concrete aggregate, which you only really tend to find in desert areas (if you're lucky enough to find a spot that hasn't been above water for more than a million years, that's one reason construction-grade stuff is so hard to find.)
Now days, I do very similar to your link, except it's through mountains, and terminates inside the mountain. Minerals extraction is fun!