Mountain ores
Extraction of minerals is carried out in several ways depending on the conditions of occurrence of rocks. Basically, a distinction is made between extraction of minerals from quarries and mines (shafts). Rocks themselves are divided by origin into:
- Igneous or igneous (deep or extrusive) rocks formed as a result of the solidification of silicate melt – magma.
- Sedimentary rocks – the formation process of which is based on the sedimentation of inorganic and organic substances in the bottom of water basins and on the surface of the earth (for example: coal, peat, oil).
- Metamorphic – crystalline rocks formed as a result of changes in igneous or sedimentary rocks under the influence of temperature, pressure and other parameters.
In turn, igneous rocks are divided into deep, extrusive and fragmental.
I Deep Rocks
- formed as a result of settling of magma in the depths of the earth's crust, this process occurs very slowly, under pressure. Under such conditions, the melt completely crystallizes, as a result of which large grains of minerals are formed. Granite, diorite, syenite and gabbro are the most common deep rocks.
Granite consists of quartz grains, feldspar grains, mica or ferrous-magnesian silicates. Average density is 2.6 g/cm3 . The main properties of granite include frost resistance, low abrasion, granite is easy to grind and polish, which is the reason for the widespread use of this mineral in the construction industry. Facing slabs, architectural and construction products, stair steps, crushed stone, etc. are made from granite.
Syenite consists of feldspar, mica and hornblende. Density is 2.7 g/cm3 . This mineral is easier to process than granite and is used for the same purposes and directions.
Diorite consists of plagioclase, augite, hornblende and biotite. In density it differs little from granite and syenite. It is resistant to weathering, characterized by low abrasion, and is used for the manufacture of facing materials and in road construction.
Gabbro is a crystalline rock consisting of plagioclase, augite and olivine. Average density is 3.1 g/cm3 . It is used for facing basements, flooring, etc.
II Erupted Rocks
- formed during the cooling of magma at shallow depths or on the surface of the earth. Such rocks include porphyry, diabase, trachyte, andesite, basalt.
Porphyries are very similar to granite, syenite and diorite. They are used to make crushed stone and for decorative and ornamental purposes.
Diabase is an analogue of gabbro. It is used for external cladding of buildings, in the production of curbstones. It has a low melting point - 1200 - 1300 C, therefore it is used for stone casting.
Trachyte is an analogue of syenite, it is a fine-pored rock. Average density is 2.2 g/cm3 . It is usually used as a large aggregate for concrete.
Andesite is an analogue of diorite. Andesite is often used as an acid-resistant material.
Basalt is an analogue of gabbro. It is characterized by a glassy or crystalline structure.
III Clastic rocks
– are volcanic emissions characterized by a glassy porous structure formed as a result of rapid cooling on the earth's surface. They are divided into loose and cemented. Loose are volcanic ashes, sand and pumice. Ashes are volcanic powders, particles up to 1 mm in size. Particles larger than 1 mm are called sand. Ashes are an integral additive for binders or binding mixtures.
Pumice - consists of volcanic glass and is a porous rock with a cellular structure. It has a low thermal conductivity coefficient. It is also used to fill lightweight concrete, as well as an active mineral additive for lime.
Volcanic tuffs are cemented, porous rocks formed by the compaction of volcanic ash and sand. Average density is 1.25-1.35 g/cm3 . Metamorphic rocks include gneisses, shales, quartzite and marble.
From the point of view of the mining and metallurgy industry, these rocks are "gutter rock" with metals in intergrowths, conventionally speaking, metals are hidden inside such intergrowths. To open the intergrowths at the preliminary stages of enrichment, the processes of grinding, crushing and screening are used. Also, the ore can be represented as a mixture of various minerals, as well as chemical compounds of metals with rock, which requires additional methods of processing the primary raw materials for further enrichment.
