The article tells about what a quarry is, what they are, how they are being developed and why they are needed at all.
Raw material extraction
Even in ancient times, people drew attention to the fact that in the bowels of the earth is concentrated a mass of various raw materials, which, if necessary, can produce a lot of useful materials. Naturally, in the first place was always the metal from which the instruments of labor and war were made. Due to the imperfection of processing methods, for a long time people used metals such as tin, copper and lead. But because of their plasticity, the tools quickly wore out, and later various alloys were invented, which were distinguished by higher hardness and stability. But with the beginning of industrial production of steel, the need for them disappeared.
However, in addition to metals, there are other useful materials in the bowels of the earth, in particular sand and various types of stone. They are mined most often in quarries. So what is a quarry? And what is mined in it? This we will understand. But first, let's define the terminology.
Definition
A quarry is a collection of minerals that are produced in an open way, that is, on the very surface of the earth, and not in mines. This word has French roots, and in the original it sounds like carrière, which means "cut". So now we know what a quarry is. But why is their development conducted on the surface and what is most often mined in them?
Technology
Most minerals and other valuable materials are concentrated underground. Depth usually depends on a particular site, material, its shape, etc. For example, coal is hidden by the thickness of the earth because it was formed from the remains of ancient plants, which gradually mineralized under pressure. There are, of course, land-based exits, they came about because of the breaks in the earth's crust. But not all substances are hidden deeply, some are located on the surface itself or lie close to it, and therefore for their extraction there is no need to build deep mines, it is much easier to open-cast mining.
Most often, the quarry looks like a large funnel, on the slopes of which, as it deepens, a spiral road is made for equipment.
So, we examined the question of what is a quarry. But what is most often mined in them?
Sand
Sand is one of the most common substances on the planet, and no one really feels a lack in it. However, how can sand be useful, why is it needed at all?
Oddly enough, sand is very valuable. Of course, not like iron, and even more so gold and silver. Glass is made from some varieties of sand , sand is added to concrete during construction, used as drainage for tunneling, and in the end, no playground is complete without a sandbox. And by the way, the sand pit after completion of development is often flooded and becomes a bathing place.
A rock
Humanity cannot do without a stone either. Naturally, not all stones are valuable, but its certain varieties. Most often it is marble and granite. Since they usually lie near the surface, they do not build mines for their extraction, but use the same quarries. Unlike sand, stone is somewhat more difficult to mine - you can’t just load it with excavators. Therefore, depending on the type, it is either crushed first with jackhammers or explosions, or special cutting machines are used. This happens when monolithic and smooth blocks are needed, which are further processed further.
A stone quarry is usually developed for many years, and its reserves are practically inexhaustible.
That's all. Now we know what a quarry is for.