Sand =! Industrial usable Sand. Not all kind of "Sand" is suited for the industry(today). Most desert/dune sand is to fine grained and has a smooth surface, so that it is unusable to create strong material. There are some projects/studies already that use "desert sand + X" to create "strong" material.
> Sand =! Industrial usable Sand. Not all kind of "Sand" is suited for the industry(today). Most desert/dune sand is to fine grained and has a smooth surface
That's why you mine it to the East, closer to where it erodes, rather than to the West, where it is fine enough to be considered dust.
http://www.resourcepanel.org/reports/global-material-flows-a...
https://na.unep.net/geas/archive/pdfs/GEAS_Mar2014_Sand_Mini...
https://www.hindawi.com/journals/amse/2016/2158706/
http://maxwellsci.com/print/rjees/v4-1071-1078.pdf