According to a long and frankly interesting piece in the New Yorker, the worldwide mining of sand and gravel is greatly exceeding natural refresh rates. Are we really running out of sand?
It helps to understand that sand is not sand. If you've never done it, do an image search for microscope images of sand; there are many different types with essentially a different type for every usage. The article starts by talking about beach volleyball, a recent addition to the Olympics. It starts with the interesting Fun Fact that beach volleyball is not played on ordinary beach sand. It's not a good surface for hard athletics.
I visited the site shortly before the tournament, and spoke with Todd Knapton, who was supervising the installation. He’s the vice-president of the company that supplied the sand, Hutcheson Sand & Mixes, in Huntsville, Ontario. ... “You want to see the players buried up to their ankles,” he said, and stuck in a foot, to demonstrate. “Rain or shine, hot or cold, it should be like a kid trying to ride a bicycle through marbles.”That's the sort of sand we're talking about being short of. It leads to what seems like an absurd situation: sand is being quarried at one place in the world and shipped long distances.
Ordinary beach sand tends to be too firm for volleyball: when players dive into it, they break fingers, tear hamstrings, and suffer other impact injuries. Knapton helped devise the sport’s sand specifications, after Canadian players complained about the courts at the 1996 Olympic Games, in Atlanta. “It was trial and error at first,” he said. “But we came up with an improved recipe, and we now have a material that’s uniform from country to country to country, on five continents.” The specifications govern the shape, size, and hardness of the sand grains, and they disallow silt, clay, dirt, and other fine particles, which not only stick to perspiring players but also fill voids between larger grains, making the playing surface firmer. The result is sand that drains so well that building castles with it would be impossible. “We had two rainstorms last night, but these courts are ready to play on,” he said. “You could take a fire hose to this sand and you’d never flood it.”
The company’s biggest recent challenge was the first European Games, which were held in Baku, Azerbaijan, in 2015. Baku has beaches—it’s on a peninsula on the western shore of the Caspian Sea—but the sand is barely suitable for sunbathing, much less for volleyball. Knapton’s crew searched the region and found a large deposit with the ideal mixture of particle sizes, in a family-owned mine in the Nur Mountains, in southern Turkey, eight hundred miles to the west.This became a problem because the mine is within shelling distance of the Syrian border. The company originally planned to truck the sand across central Syria, through Iraq, around Armenia, and into Azerbaijan from the northwest, in two convoys of more than two hundred and fifty trucks each. That's when they had to consider Isis and the Syrian civil war. Instead they bagged the sand into one-and-a-half-ton fabric totes, trucked it west to Iskenderun in Turkey and loaded it onto ships. “We did five vessels, five separate trips.” Just think: five separate ships carrying sand to Azerbaijan.
In the industrial world, [sand] is “aggregate,” a category that includes gravel, crushed stone, and various recycled materials. Natural aggregate is the world’s second most heavily exploited natural resource, after water, and for many uses the right kind is scarce or inaccessible. In 2014, the United Nations Environment Programme published a report titled “Sand, Rarer Than One Thinks,” [pdf warning] which concluded that the mining of sand and gravel “greatly exceeds natural renewal rates” and that “the amount being mined is increasing exponentially, mainly as a result of rapid economic growth in Asia.”China’s swift development consumed more sand between 2010 to 2014 than the United States used in the entire 20th century. In India, commercially useful sand is now so scarce that markets for it are dominated by “sand mafias”— criminal enterprises that sell material taken illegally from rivers and other sources, sometimes killing to safeguard their deposits.
As a general rule, civil engineers will say that it's not cost-effective to ship sand more than about 60 miles, so that builders tend to use whatever is available even if it's not optimum. Living in Florida, it's a strange thought that we don't have any good sand. I've often thought that our motto shouldn't be "the sunshine state" but rather "the sand state". Our beach sand, though, is mostly broken bits of shells and is doesn't work well as aggregate.
In some places, though, there are no usable alternatives. Florida lies on top of a vast limestone formation, but most of the stone is too soft to be used in construction. “The whole Gulf Coast is starved for aggregate,” William Langer, the research geologist, told me. “So they import limestone from Mexico, from a quarry in the Yucatán, and haul it by freighter across the Caribbean.” Even that stone is wrong for some uses. “You can build most of a road with limestone from Mexico,” he continued, “but it doesn’t have much skid resistance. So to get that they have to use granitic rock, which they ship down the East Coast from quarries in Nova Scotia or haul by train from places like inland Georgia.”
Given this is "The New Yorker", which seems to have lost the cartoons it once had a great reputation for, I was expecting to find the greenie tone something like "ZOMG! We're even using up all the sand on Earth!!", and it's thankfully light on that. From beach volleyball courts to the man-made islands offshore Dubai to (what I've always thought of as) the nonsensical "beach replenishment" by dredging sand offshore and depositing it on the beach, it's just an interesting article on a part of life the typical person never thinks about.