The world's largest mining industry, and perhaps the most destructive, we rarely see in the media or talk about it. About 85% of all material extracted from the earth is a simple and widely available resource: sand.
So, being so cheap and easy to get, it is mined by everyone from a guy with a shovel to multi-million dollar machines. Most of the sand is used to make concrete, but the extraction of sand condemns the destruction of coastal ecosystems, sea and river beds, and topography.
The United Nations Environment Program estimates that 40 billion tons of sand are mined each year, but as the market is corrupt, hidden and decentralized, no comprehensive studies have been conducted to date.
In order to obtain an approximate figure, the United Nations used worldwide cement production and sales figures to approximate the amount of sand that is collected. For example, each ton of cement requires six to seven tons of sand and gravel.
Sand mining, especially when done without regulation or supervision, can damage rivers, cause beach erosion, and destroy coastal ecosystems. At least 24 Indonesian islands disappeared from the map just to build Singapore.
Since sand dredging is done primarily for construction purposes, miners focus on river and coastal ecosystems where sand is ideal. River sand is particularly perfect for concrete because it is thick and does not contain salt that would otherwise corrode metal and other building materials. Furthermore, altering the flow and capacity of rivers can cause disastrous droughts or floods, although it is rarely recognized as a contributing factor.
In Kerala, India, floods were shown to be partially caused by sand dredging that removed 40 times more sand from the river bed than the river could naturally replace.
Seafloor dredging can also cause sediment to drift for miles causing coastal erosion and suffocating ecosystems such as coral reefs. Erosion, land subsidence, and the introduction of machinery and heavy vehicles into sensitive habitats also threaten the integrity of nearby infrastructure, such as roads and bridges.
One study showed that every ton of sand pulled from a river in California costs taxpayers $ 3 in damage to infrastructure.
Cities' demand for sand
Development and urbanization are expanding rapidly in all corners of the world to accommodate an exponentially growing population and our insatiable rates of consumption and expansion.
According to the United Nations, the number of people living in cities is more than four times higher than in the 1950s. More than 50% of the world's population now lives in urban areas, and nearly three billion are expected to live in cities. more people migrate to cities in the next 30 years.
In addition to new buildings, sand is also used to gain ground from the sea. In China, it is a common practice to dump sand on coral reefs to gain land. Dubai is also famous for its artificial islands, which required millions of tons of sand.
Singapore has added more than 50 square miles of land in the last four decades and more skyscrapers in the last 10 years than all of New York, a feat that required more than 500 million tons of sand. The construction of Singapore was so rapid that Indonesia, Malaysia and Vietnam banned the export of sand, but the miners simply moved to Lake Poyang on the Yangtze River. WWF calls this lake the largest sand mine in the world, but tragically it is also the largest destination in Asia for migratory birds. Sand dredging activities have more than doubled river capacity in some areas, draining parts of the lake and reducing major fisheries.
The scale of the problem is enormous and the consequences of moving large amounts of material for the life and maintenance of the earth from one place to another are evident, but the world remains functionally unconscious, blinded by the desire for new buildings and modern neighborhoods. .
Can sand be dredged sustainably?
River ecologists suggest that sand dredging in rivers should only be done up to a predetermined quota that allows the river to annually replenish sediment. However, this sustainable number will never match humanity's unsustainable need for development.
A simple rule of thumb is that the extraction of sand in rivers should not exceed the rate of replenishment of sand from upstream.
There are a number of suggestions for improving the sustainability of the industry, but none are perfect:
Offshore sand mining
Britain now sources much of its sand further offshore to protect river and coastal ecosystems, however much of this sand is only used for land reclamation projects where salt content is not a concern. concern.
Sandy bottom deposits
Another untapped source is sand that accumulates at the bottom of reservoirs. These could not only provide sand, but also help expand storage capacity. Environmentalists, however, argue that this sand should technically be returned to the rivers that feed the reservoirs.
Glass and debris recycling
Rubble from demolished buildings can be used to produce concrete, reducing the need for fresh sand. Glass can also be recycled, again reducing the need for sand.
Limited mining on floodplains, rather than on river banks and river beds, is considered less destructive. However, floodplains also have fragile ecosystems. In Australia, the floodplains are home to rare species of carnivorous plants that are now at risk from mining activities.
Substitution of sand in concrete
Ash from incinerators and dust from stone quarries can be used in the production of concrete to reduce the demand for sand.