Shifting sands, the grains that make the world go round
4 min read
What would you guess is the world’s most mined product – the one thing we extract from the ground more than anything else? Oil, perhaps? Coal? Iron, or maybe copper?
Actually, the answer, by a country mile, is sand. We dig and quarry and blast more sand, gravel and crushed rock than any other material. More, indeed, than all fossil fuels and metals combined.
For anyone who spends little time pondering sand, save for that moment you need to empty your shoes after visiting the beach, all of this might come as a surprise. But sands of various types represent the hidden substrate that keeps the modern world turning. And there are many, many different varieties of sand.
There are so-called ‘sand mafias’ who dig and sell sand on to the construction trade
There are the coarse, angular grains we mostly use in construction – the kinds of sand you usually find on riverbanks. There are marine sands sitting on the seafloor until they are dredged up and turned into new land. There are desert sands, so worn by the wind that when you study them under a microscope they look like marbles – the edges of the grains rounded down by thousands of years of friction.
Then there are specialised sands, some of which are so rare that they occur only in a few places on the planet: incredibly pure silica sands which can be melted down and turned into the clearest glass; ilmenite sands which are a source of titanium; high-purity quartz sands which can be moulded into the crucibles we need to make silicon chips.
Sand, it turns out, is both the substance we use to make the world’s most advanced technology (from the semiconductor to silicon carbide circuitry to precision optics) and the world’s most widely deployed construction material: concrete.
Without concrete we would struggle to build anything these days. Our roads, our bridges, our buildings are made in part from this extraordinary material whose chemistry remains a mystery to scientists and whose recipe was lost for thousands of years until it was reimagined during the Industrial Revolution. And you cannot make concrete without the sand and aggregates we dig from the ground in astounding quantities.
That we pay so little attention to all this might be because so much of it happens out of sight. Most of London’s construction sand is dredged from under the North Sea, from Dogger Bank, the old landmass that used to connect this country to the continent. Dredgers occasionally encounter mammoth tusks and old Stone Age axes as they remove the sand from what was once a riverside.
Remember this the next time you encounter concrete in the City: these seemingly boring, brutalist slabs were reconstituted from a drowned land over which our ancestors once roamed.
But while Britain’s sand miners are heavily regulated and are careful to mine only from old fossil river systems, on the other side of the world much of the sand going into concrete and earthworks is extracted in a far less sustainable way.
Vietnam’s Mekong Delta – the source of a large proportion of the food for that country (and much of Asia) – is under ecological threat because of enormous sand mining along its banks. Sand mining has become such a problem in China that police regularly arrest illegal dredgers along its rivers. In India there are so-called “sand mafias” who dig and sell sand on to the construction trade. In Morocco, vast stretches of the country’s beaches have been removed, with the sand shipped away on barges and used sometimes to replenish beaches in Europe, sometimes in construction.
This is happening at such a rate that the United Nations Environment Programme says we are heading for a “sand crisis”. Some have even projected that we could run out of construction sand by 2050.
The idea that the world could run short of something that is so plentiful might seem preposterous. But that is to forget that not all sands are alike. And we are consuming those special, sought-after varieties at a breakneck pace.
Ed Conway, economics and data editor of Sky News and author of Material World: A Substantial Story of our Past and Future
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