Where do minerals come from?
Do you know what a plastic bag, lipstick and chewing gum have in common? You will be surprised, all these products are made from petroleum! And you will be even more surprised to learn how many things you are used to were made from raw materials that until recently were located at depths of hundreds of kilometers. These are natural resources. They can be solid (like coal or gold), liquid (water, mercury) and gaseous (for example, hydrogen sulfide). A long time ago, a caveman figured out how to attach a stone to a club and chased bison with this simple weapon. And as soon as ancient people learned to mine and process metals – copper, bronze, iron – this gave a gigantic impetus to the development of mankind. Iron coulters (plow tips) made it possible to effectively cultivate the land, strong and sharp spears and arrows helped in hunting, the quality of wood processing improved, as a result of which navigation and construction flourished, etc., etc. Today, minerals are also a source of energy, they are also raw materials for the production of various alloys, building materials, chemicals, and much, much more. Russia occupies one of the leading places in the world in mining. We are the first in terms of reserves of gas, iron ore, nickel, silver and diamonds. We are among the top three world leaders in gold, coal, tungsten, antimony, natural gas and a number of others. At the same time, many deposits are located in Siberia. Just imagine what a huge area and harsh climate there are. Mining has always given a powerful impetus to the development of the region. After all, it’s not enough to get to the fountain of oil gushing from the ground, because you still need to somehow deliver the raw materials to the factories and provide the workers with comfortable living. Therefore, railway lines are laid to rich and promising deposits, processing plants are built, and entire cities grow nearby. For example, areas such as the Arctic and the Far East are now considered the most promising. There are so many different minerals on the territory of our country, not only because of the gigantic areas, but also because of the diversity of tectonic structure. Over millions and millions of years, a huge amount of oil, phosphorites, bauxites, apatites and precious metals were formed in the foundations of tectonic plates under the influence of colossal pressure and time. Well, in addition to the plains, which occupy two-thirds of the area of our country, one third are mountains. And magma rising from the depths of the earth is ore minerals (ferrous and non-ferrous metals). These unique geographical features and combinations give us almost a quarter of the total reserves of all the natural resources of the world. But it is not enough to have wealth, these riches still need to be obtained. But here’s the catch: mining is becoming more difficult year after year. Everything that was easy to get to had already been dug up and used long ago. Modern drilling rigs can dive to a depth of more than three kilometers. Amazing installations are sent to the seabed, which collect silver and gold from the surface and transport precious metals to the surface like through the hose of a giant sea vacuum cleaner. Land and mineral resources are our wealth, which we must manage carefully. Despite the fact that most of them are non-renewable resources, we are provided with reserves for hundreds of years to come. Did you know that The first diamond in Rus’ was found 190 years ago by a serf boy, Pavel Popov, who worked in a gold mine. For this find, Pavel was given his freedom. And at the site of the find there was a stone with a memorial plaque. Permafrost, which makes some northern regions completely uninhabitable, is an unexpected boon for mining. Thus, the kimberlite pipe in Yakutia (essentially a gigantic “well” with almost vertical walls, dug many kilometers deep into the Earth) does not crumble, thanks to the completely frozen soil. The world’s first surgical instruments were made from volcanic glass – obsidian. Under certain conditions, magma erupting to the surface turns into mineral. If you split this frozen stone, which looks like dark glass, you get pieces with very sharp edges. The Nord Stream gas pipeline, built by Russia, Germany, the Netherlands and France, is the longest undersea gas export route in the world: its length is 1224 kilometers. There are two methods of mining: open (in quarries and open pits) and closed (in mines and quarries).
Relevance of open-pit mining
Open-pit mining is the first method of extracting minerals available to man. It is still relevant today: 65% of the world consumption of raw materials of ore and non-metallic origin is mined by open-pit mining, as is 35% of solid fuel. 20-30% of hard coals and almost 90% of brown coals are extracted from open-pit mines; 80% of non-ferrous metal ores, 75% of iron ores and 90% of other minerals and building materials are also mined in quarries. Quarry mining is most developed in the USA, China, Australia, Canada, and some European countries. In Russia, almost 100% of construction materials, 64-66% of coal and 80-93% of ferrous and non-ferrous metal ores are obtained through open-pit mining.
Advantages of open pit mining
The main advantage of open-pit mining is financial benefits. Open pit mining is 2 times more efficient than underground mining for ore deposits and 3 times more efficient for coal seams. Open-pit mining of minerals allows saving on the construction of mines and tunneling; at the same time, labor productivity in open-pit mines and quarries is 2-3 times higher than in underground mines, and the loss of useful raw materials is 5 times lower. An important factor is also that when extracting ores by open-pit mining, it is possible to comprehensively develop all the resources of the deposit.
Quarry and open pit
The set of mine workings formed during open-pit mining is called quarries. In Russia, the term open pit is used to refer to quarries where coal is mined and placer deposits are developed. A quarry is a system of benches (most often the lower benches are mining, less often rock, and the upper benches are rock or overburden) of a rock mass within the contours of a quarry field. As a result of stripping operations, the cap rocks are moved to dumps (sometimes they are placed in the mined-out space). Mining operations allow for the extraction of rock and its transportation to an industrial site for primary processing of minerals or shipment to the consumer.
Efficiency of open pit mining
During operation, the working benches move, resulting in an increase in mined-out space. The depth of the quarries is determined by the efficiency of open-pit mining. Most often, the benefit from further development is lost after tens to five thousand meters, but there are exceptions – the depth of Bingham Canyon (Utah, USA), which began to be developed in 1863, reached 2008 km by 1,2. The stripping ratio (the ratio of the total volume of overburden in the quarry contour to the entire volume of minerals) usually ranges from 4 to 25 m3/m3. Although the use of modern equipment (for example, crushing buckets) increases the efficiency of development of deposits with a low content of useful components in the ore, higher values of this indicator make development unprofitable. The efficiency of a quarry is assessed comprehensively, using a system of technical and economic indicators, both special (stripping ratio, cost of minerals, operating costs, etc.) and general (profitability, profit, quality of mining products).
Drilling and blasting costs. Is it possible to save money?
The lion’s share of costs in the extraction of solid minerals is the cost of drilling and blasting operations, they amount to up to 30% of the cost. In addition to the financial aspect, drilling and blasting has other disadvantages: technological complexity, increased danger, serious damage to the environment, over-grinding of hard rocks. Since 1996, Russia has been developing non-explosive technologies for the development of hard rocks. Today, the refusal of drilling and blasting in the development of soft, fairly soft and medium-hard rocks on the M.M. scale. Protodyakonov is reality. Many quarries have been able to increase their efficiency by replacing explosions with modern equipment – mega-rippers, membrane hydraulic hammers and rotary cutters.
History of mining development
The first primitive mining tools found by archaeologists date back to the sixth millennium BC. In the fourth millennium BC, polymetallic ores were extracted by open-pit mining in India, the Caucasus and the Sinai Peninsula, as well as in Northern Ethiopia. Since the second millennium BC, iron has been mined using quarries in Southern Europe and the Middle East. The first large-scale stone quarries appeared thanks to the construction of temple complexes and pyramids in Ancient Egypt; subsequently, marble was extracted by quarrying in the period of antiquity. In the Middle Ages, open-pit mining of non-ferrous metals was carried out in large quarries in the lands of modern Italy, Spain, and also in the Urals. Since the 18th century, quarrying for placer deposits in Siberia and the Urals has been gaining popularity. But only in the 20th century, with the advent of high-performance machines and equipment for large volumes of stripping operations, large-scale excavation of rocks, their loading and transportation, significant progress was recorded in the industry.
Development of mining in the 20th century
The first mining excavators appeared at the end of the 19th century. This gave impetus to the rapid development of industrial open-pit mining of natural resources at the beginning of the 20th century. Germany and the USA have become leaders in this direction. In Russia at that time, manual labor still predominated, and work was only partially mechanized. In the USSR, large quarries where ferrous and non-ferrous metals, as well as open-pit coal were mined, appeared in 1928-1941. During the Great Patriotic War, the volume of mineral extraction in the USSR increased significantly. At the end of the war, a period of modernization of equipment and mechanization of the mining process began. At the same time, blasting techniques were progressing. Gunpowder, which began to be used back in the Middle Ages, was replaced by ammonal in the 20s, dynamon began to be used in the 30s, oxyliquit was used in the 40s, and then they switched to igdanite, which is still used today, although in more modern formats.
Open pit mining. Preparatory stage
Any mineral extraction – be it open pit or underground – begins with geological exploration. Then, after approval of the project, preparatory work begins (drainage of the field, diversion of rivers, relocation of railways and highways, deforestation, construction of utility, administrative, and storage facilities, construction of communications, garages, workshops, and so on). The complexity of this stage directly depends on the natural and geographical conditions of the area.
Mining and capital works
After the preparatory stage, capital mining work at the site begins (this stage is also called the main mining construction period). Capital and cutting trenches are created, drainage and drainage work is carried out, the installation of main mining, transport and technological equipment is underway, industrial buildings, processing facilities are being erected, and so on. During the same period, the opening of the deposit takes place, when overburden rocks that interfere with the extraction of minerals are separated by mechanical loosening or with the help of drilling and blasting.
Field exploitation
The longest stage in the life cycle of any quarry is the period of operation. It is important to achieve the most complete, safe and economical extraction of all types of minerals. To do this, it is necessary to select a production technology that will most accurately suit the conditions of a particular field.
Land reclamation
Any mining technology involves the movement of huge volumes of soil and rocks, which means it inevitably disrupts the natural landscape and the balance of the local ecosystem. From the point of view of ecologists, the quarry has extremely negative consequences for nature: during its creation and operation, the soil cover is disturbed, forests are destroyed and the pattern of groundwater movement changes. The machinery operating in the quarry produces a huge amount of dust, which settles in the nearby forests. To reduce the negative footprint, at the end of exploitation the quarries are flooded or reclaimed. In many countries, mining owners are required by law to restore the soil and plant trees in an abandoned quarry.
Various classifications of mining technology
Since each field is unique, development is carried out using various techniques and approaches. The productivity of a quarry depends on the correct choice of development technology. There are several options for classifying mining operations. In Russia, the N.V. classification of open-pit mining systems is widely used. Melnikov on the method of moving waste overburden into dumps and the type of equipment used.
| Extraction method | Description |
|---|---|
| Extraction method Non-transport | Description Overburden rocks are moved to internal dumps directly by excavators |
| Extraction method Transport-dump | Description Overburden rocks are transported to internal dumps using mobile transport and dumping units |
| Extraction method Special | Description Overburden rocks are removed by wheel scrapers, using hydromechanization means, etc. |
| Extraction method Transport | Description Overburden rocks are transported to internal or external dumps by means of quarry transport. |
| Extraction method Combined | Description Overburden rocks from the upper benches are removed by quarry transport, and rocks from the lower benches are moved to internal dumps directly by excavators or using mobile transport-dumping units |
Based on the position and shape of the deposits relative to the surface of the earth, the following methods of development of deposits are distinguished.
| Extraction method | Description |
|---|---|
| Extraction method Surface | Description Provides for the complete development of the site and the processing of the maximum volume of not only minerals, but also overburden works that are located in the mined-out space of the quarry |
| Mining method: Deep | Description Overburden is removed in layers in a descending order |
| Nagorny mining method | Description Overburden and minerals move from top to bottom to deeper levels |
| Mining method Upland-deep | Description A variation of the mountain method for difficult terrain |
| Production method Subsea production method | Description When the deposit and its roof are located under water |
Another classification developed by V.V. Rzhevsky, is based on the position of the working area and the direction of movement of the work front.
| Extraction method | Description |
|---|---|
| Extraction method Continuous | Description Ore is mined from horizontal or gently dipping deposits (overburden dumps are placed in the mined-out part of the quarry or outside it) |
| Mining method Deep | Description Development of steep and sloping deposits with overburden deposited in external dumps |
| Extraction method Mixed | Description Used for developing deposits in difficult mining, geological and topographical conditions. |
Also used is the one developed by K.N. Trubetskoy’s classification of systems based on resource-saving and low-waste technologies using new types of mining and transport equipment, which includes cyclic (13 schemes) and cyclic-flow (5 schemes) methods of open-pit mining.
Technical equipment of a modern quarry
A modern quarry is a high-tech enterprise equipped with productive machines and mechanisms. For mining, both highly specialized machines and complex units capable of performing several tasks at once are used. For example, loosening is carried out by rippers with a power of up to 735 kW, drilling of blast holes is carried out by drilling rigs weighing up to 130 tons. For stripping operations, mechanized shovels and draglines with a bucket capacity of about one and a half hundred cubic meters are used. To increase the efficiency of deposit development, comprehensive mechanization is being actively implemented, which includes the continuity of communications – from the point of slaughter to the points of ore unloading. With this approach, all machines involved in the technological chain must correspond to each other in terms of productivity and power.
Choosing equipment for a quarry
It is interesting that the technical equipment of a particular quarry depends, among other things, on its location and national traditions of the industry. Thus, in Germany it is customary to use transport and dump complexes for coal mining. In the USA, at comparable scales of mining, large excavators are used at coal mines. And yet, the most popular in open-pit mines around the world are straight shovels, excavators and articulated loaders. A quarry excavator can not only load and transport rock. Depending on the strength of the rock and the technological need, a hydraulic excavator can be equipped, for example, with a rotary bucket for crushing the extracted rubble stone into crushed stone. And when extracting limestone, a mega-ripper, hydraulic hammer or rotary cutter installed on an excavator will allow you to abandon drilling and blasting operations and obtain high-quality products without over-grinding.
Features of flow technology
The flow technology for developing mineral reserves involves the active use of self-propelled crushers and bucket wheel excavators, and the mass of such crushers reaches 600 tons. The use of stationary and mobile crushing units makes it possible to widely use conveyor systems. However, the main transport unit of any quarry is, of course, a dump truck. Most often, vehicles with a carrying capacity of up to 155 tons are used, but there are also real giants (200-300 tons). However, we should not forget about 360-ton railway tractors with dump cars with a carrying capacity of up to 180 tons.
Large machines – large costs
The development of the mining industry requires the creation of new, more powerful and advanced machines and equipment. But the downside to the efficiency and productivity of such colossuses is the huge financial costs. When creating a quarry up to a hundred meters deep with hard rocks, 15% of the cost is the construction of the quarry. Of these, 40% of expenses are mining operations, 30% are the cost of equipment. During operation, 30% of the cost per cubic meter of overburden is taken up by blasting and drilling operations, about 15% by excavation, and another 40% by transportation. As the quarry deepens, transport costs can increase by up to 70%. Construction of a quarry requires serious capital investments, and their payback period ranges from 7 years or more. But as the huge scale of open-pit mining around the world shows, the labor-intensive production process and high costs do not scare investors. You can ask HammerMaster specialists any question you are interested in
