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Demand for sand (for concrete) is killing rivers... in Africa In the US, dredging rivers or land near a waterway is pretty restricted. Sand is typically mined
by payne92 9y ago
Demand for sand (for concrete) is killing rivers... in Africa
In the US, dredging rivers or land near a waterway is pretty restricted. Sand is typically mined from open pits, see: https://en.wikipedia.org/wiki/Sand_mining#United_States https://en.wikipedia.org/wiki/Sand_mining#United_States
- maxerickson 9y agoDoes anyone know how much of it comes down to geology? A lot of the accessible sand in the US is from glacial deposits. Wisconsin is mentioned in the Wikipedia article as having a boom in sand mining and the surface geology there is nearly entirely a result of glaciers.
- beex 9y agoThe situation is much the same[0] in many other parts of the world. [0]: http://www.smithsonianmag.com/science-nature/world-facing-global-sand-crisis-180964815/ http://www.smithsonianmag.com/science-nature/world-facing-gl...
- tryingagainbro 9y agoIsn't the river sand full of mud, in many cases? Can it really be washed that well?
- jaclaz 9y agoNot only it can be washed perfectly but river sand (and gravel) tend to be much better for concrete when compared to "crushed" aggregates. More or less the reason is that usually for a given size river ones are harder/more resistant, and have rounded edges (which also imply a bigger resistance) due to the cycles (wear, long time immersion, etc.) they were subjected to in the river. And, as a final advantage, concrete made with rounded aggregates is usually easier to pump.
- PhasmaFelis 9y agoMud is just soil in water, and drying and sieving soil is easy.
- dang 9y agoOk we've sent the title above to Africa.