Interesting article. However sand is just mostly ground up quartz (silicon dioxide). It is the second most abundant mineral in earths crust. We could just grin

Interesting article. However sand is just mostly ground up quartz (silicon dioxide). It is the second most abundant mineral in earths crust. We could just grind rocks instead of causing erosion in water ways. However, we would need a good energy source to run a grinder/crusher. We are improving along those lines of energy production. Natural, sand is made by wind and hydro power. So if we keep it that way we should fine. Also it seems to more of we are collecting sand and other aggregate in haphazard way. I am not sure I would call that running out? Unless sources with low environmental impact are running out?