At a depth of a couple of kilometers under the volcanoes, reservoirs of hot and concentrated solution are formed, rich in copper, gold and other metals: they can be extracted from this liquid, at the same time receiving geothermal electricity.
Every year the needs of mankind for non-ferrous and rare metals are growing. Prices are rising, developments are expanding, causing tremendous damage to the environment and even causing armed conflict. To reduce this harm by making it easier to extract copper and other metals, Oxford scientists suggested taking a closer look at volcanoes, where they can be extracted from solution and, in parallel, receive green geothermal energy. Jon Blundy and his colleagues write about this in an article published in the journal Open Science.
Indeed, many of the common deposits of non-ferrous metals were formed in the distant past due to the activity of volcanoes. During the eruption, a hot concentrated solution containing copper, as well as zinc, lithium, silver and gold is carried to the surface. Some metals are eventually released into the atmosphere, but some remain in the ground, cools over time and form deposits.
And under an active volcano, at a depth of a couple of kilometers, large volumes of metal-rich liquid can accumulate. It is theoretically possible to extract resources from it with much lower costs and damage to nature than from stone ore. At the same time, the high temperature allows you to simultaneously receive geothermal electricity, which can be used to power mining equipment and infrastructure.
Oxford geologists have shown that such metal-rich solutions persist in porous rocks beneath active volcanoes in Italy, Japan, Mexico, Indonesia and the Antilles. According to their conclusion, almost every active volcano in the world can have such reservoirs - a real gold mine, sometimes in the literal sense of the word. For example, the New Zealand volcano White Island, according to scientists' calculations, emits about 100 tons of copper and 4.5 kilograms of gold per year, but much of it remains in deep reservoirs - in the form of a saturated hot solution.
Unfortunately, mining them will require the creation of new tools and technologies. A saturated solution, sometimes heated to plus 450 ° C, is highly corrosive, and pipes and equipment with special coatings are needed to work with it. In addition, it is necessary to accurately assess the risk of provoking an eruption.
So far, scientists do not believe that it is large, since metal solutions lie above the "heart" of the volcano - magma chambers located at a greater depth. However, this is worth checking, and geologists are already selecting a site for the first experimental drilling. According to them, the real development of volcanic resources can begin in 5-15 years.