mining

the branches of science and technology that embrace the processes of extracting minerals from the interior of the earth.

For thousands of years mining was limited to the extraction of only solid minerals (nonmetallic construction materials, ore, and so on). The extraction of petroleum began in the second half of the 19th century; that of natural gas, in the early 20th century.

The extraction of minerals is preceded by prospecting, which is necessary to determine the reserves, ore quality, and economic feasibility of exploiting a given deposit, the production capacity of a mining enterprise, and the methods of working deposits. Geophysical prospecting methods are being used more widely; geochemical and microbiological prospecting methods are in the process of further development. The results of prospecting surveys and stereogeomet-ric measurements are represented on maps, plans, sections, and charts by means of mining-surveying and geometric methods.

When sufficient mineral reserves have been discovered and the technical and economic feasibility of exploiting them has been shown, development of the deposit is begun on the basis of a preliminary plan. This is done by drilling holes or excavating a network of underground or opencut mines according to a specific plan; the necessary surface and subsurface facilities are constructed for stripping the deposit.

Industrial shaft operation specifications require a minimum of two exits from underground mines to the earth’s surface: one for the fresh air supply, and the other for exhaust air. These exits are usually the openings to the deposit and the network of interconnected workings, such as vertical or sloping mine shafts and tunnels. The depth of vertical shafts may exceed 2,000 m in some cases. The methods of sinking shafts and other mine workings depends on the nature and degree of flooding of the rock through which they are cut. To prevent collapses, mine walls are braced in proportion to the amount of rock excavated.

After the deposit has been stripped, so-called development is begun on the mineral with the purpose of preparing the deposit for the cleaning work. Upon completion of the development work, the cleaning work is begun in order to extract the mineral. The faces for performing the cleaning work are called the working faces, and the resulting workings are called excavations. The temporal and spatial procedure of the development and cleaning work, which is established for specific natural, geologic, technical, and economic conditions, is called the system of working the deposit.

The preliminary excavations and the cleaning work for the extraction of the minerals are usually performed by drilling, rock-loading, and cutting-loading machines.

The extracted mineral is delivered from the working face to the earth’s surface by means of a mine conveyor system; loads and personnel are transported along the mine shaft by a mine hoist.

All underground mines are supplied with fresh air. Stationary electric lighting is installed in the underground workings, and the workers are furnished with portable miner’s lamps. The water that accumulates in underground workings is continually removed by a drainage system. Special services monitor the regularity and safety of underground operations, and measures are taken to prevent and extinguish fires and to cope with accidents and their consequences.

Mining had its beginnings at an early stage in the development of human society. During the period of the tribal system underground mines, sometimes supported by wood, were excavated for the extraction of silicon. Stone implements and picks made from antlers were used for mining. The systematic mining of copper and tin ores and the extraction of gold and silver began in slaveowning society. Remains of ancient mines from the Bronze Age have been discovered on the territory of the USSR. Mine workings with traces of supports and ladders from the same period have survived in Central Europe. Mining existed in China, Japan, and regions of the American continent long before the Common Era.

The mastery of the production of iron became the main factor in the development of the productive forces in ancient society. The mines exploited the labor of huge numbers of slaves and convicts. Mining played an important role in the economy of ancient Rome toward the end of the Republic era and during the Empire period (first century B.C. to the third century A.D.).

Significant progress was made in mining with the development of feudal relations. In the 11th to 13th centuries extensive developments began to take place in mining in Central Europe, although rocks were still drilled by hand. Important improvements were made in mining in Europe during the 15th and 16th centuries. The use of the horse drive and the waterwheel for mine hoisting and drainage devices permitted mining operations down to a depth of 150 m. Blasting operations appeared and began to replace the firing method of demolition. Wet ore concentration was introduced, making possible the mining of relatively low-grade ores. In 1512 a charter for a wet stamp mill was granted in Saxony. Timber flooring for the movement of carts loaded with minerals was first installed during that period. The first mining schools were established, and manuals on mining appeared (On Mining and Metallurgy by G. Agricola, 1556). Steam engines, which were used first for pumping water (the Englishman T. Newcomen in 1711–12) and later for mine hoisting, found application in mining earlier than in other industries.

The changeover to the large-scale use of machinery in mining was accomplished in the period of the industrial revolution (late 18th to early 19th century). In 1815 the Englishman H. Davy invented a safe miner’s lamp. Drilling technology was improved, explosives were used more and more widely, and horse-drawn rail hauling was introduced. Steel cables for mine hoisting and hauling were first used in the 1830’s. The first efficient coal-cutting machines appeared in the mid-1850’s.

The conditions for the development of mining underwent a change once again between the late 19th and early 20th centuries because of a huge increase in the demand for minerals. The technology of sinking mine shafts developed intensively. Improved sinking, ventilating, and drainage methods allowed mining depths to be extended to 1,000 m and sometimes to 2,000 m. Highly efficient systems were created for mining coal and ore deposits. Electric drive was introduced for hoisting machinery, pumps, and ventilators, mine transportation was electrified, cutting was mechanized by means of coal-cutting machines, and pick-hammers operated by compressed air were widely adopted. Independent scientific and technical disciplines emerged that were concerned with questions related to the extraction of separate types of minerals, such as coal, ores, petroleum, and peat.

The major challenges confronting mining in the USSR are the rational use of mineral resources, significant increases in economic efficiency, and the improvement of working conditions (mining is the most difficult and dangerous area of the large-scale use of labor). Intensive searches are underway for new systems of mining deposits, more powerful mechanical equipment, the use of automation, and the construction of an extraction technology based on flow production. The mechanization of the breaking and loading of coal continues to increase; the loading of coal and rock in development workings is performed by cutting-loading and loading machines. Breaking and loading during the extraction of ore is also being mechanized. The use of automation and remote control of machines and equipment is expanding gradually. The mining industry is adopting the use of metal supports (in place of wood supports) and movable powered supports. There is a marked tendency to reduce in every possible way the disconnectedness of mining operations and to speed up excavation in a relatively limited number of faces. In view of this, high-output mines are being put into operation.

Increased mining efficiency is achieved primarily by the wider adoption of opencut deposit mining methods. With the opencut mining method, labor productivity is 7–10 times higher than that of underground mines, and the prime cost of extraction is considerably lower. Extraction by the opencut method increased sharply in the coal industry during the second half of the 1950’s. The relative proportion of quarry-extracted coal rose from 6 percent to 30 percent in the total world balance over the period from 1913 to 1968. In the USSR, 25 percent of the coal extracted in 1968 came from quarries.

In the USSR (1969) the opencut mining method accounted for 77 percent of the iron ore, 64 percent of nonferrous metal ores, 56.4 percent of the manganese, 46.6 percent of mining chemicals, and 100 percent of nonmetallic minerals and construction materials.

A great deal of progress has been made in the study of the physical properties of rocks, making it possible to arrive at the optimal solutions in the design and construction of rock-crushing machinery and tools, as well as in mineral recovery methods.

Theoretical and experimental work is continuing in various areas of mining that offer the possibility of the subterranean extraction of minerals without the use of human labor (by geotechnological methods), as well as the extraction of minerals from the ocean floor.

The extraction of liquid and gaseous minerals, which accounted for approximately 60 percent of the USSR’s fuel balance in 1969, has increased immeasurably, especially during the period from 1960 to 1970. The development of the extraction of these minerals was closely associated with the development of well-drilling technology. The exploitation of petroleum deposits is conducted at great depths in the sea by artificial action on the stratum (for example, by flooding). The gas industry of the USSR is creating efficient gas fields with annual outputs of 75–100 billion cu m and large-diameter main gas pipelines.