Hydromechanization

Hydromechanization

 

a method of mechanizing earthmoving and mining operations in which all or most of the engineering processes are carried out by the power of a moving current of water.

The use of water power for construction and mining operations was known approximately 2,000 years ago. For example, in the first century B.C. water was used for working gold-and tin-bearing placer deposits. Subsequently, the power of a current of water was used to excavate canals and ditches and to build irrigation systems.

An important stage in the development of hydromechanization in prerevolutionary Russia was the organization in the 19th century of numerous gold placer mines in the Urals and in Siberia, where hydraulic mining operations were used extensively to collect gold in the water current and to pack the sand-clay refuse on dumping grounds. The gold-containing sands were worked with a pressurized stream of water regulated in the upper reaches of valleys and delivered to the mine faces through wooden and metal pipes. The works of Russian scientists (P. P. Mel’nikov in the 1840’s, I. A. Time at the end of the 19th century, and others) established the theoretical principles of hydraulic-monitor working and hydraulic transportation of rocks. The development of hydromechanization in Russia was also facilitated by the formation of the Gidrotekhnik Joint-stock Company (1874) to perform dredging operations. The underwater excavation of peat was suggested in 1916, and the first tests on the underground hydraulic mining of coal were carried out at the Sofiia Mine in Makeevka (1915).

In the USSR the development of hydromechanization in mining began after the successful working of ozokerite, by means of a dredge, organized by N. D. Kholin in 1928 on the island of Cheleken in the Caspian Sea. It was after this that the hydraulic method of production operations came to be called hydromechanization. Hydromechanization was successfully utilized in building the Dnieper Hydroelectric Power Plant (1929). In 1935-36, 95 hydromechanized units moved more than 10.5 million cu m of soil in the construction of the Moscow Canal. It was also during this period that the first Soviet soil pumps (hydraulic dredges) and electric dredging equipment were created. Technology was developed for the hydraulic excavation and grading of sand and gravel with a large content of rock waste, as well as methods for building earth-fill dams.

During the Great Patriotic War hydromechanization was extensively developed for carrying out operations in opening up coal columns in the Urals. Later this experience was extended to the Kuznetsk and Kansko-Achinsk coal basins. In the coal industry, hydromechanization was used in 6-7 percent of the stripping operations, with high technical and economic performance values.

During the postwar years hydromechanization was used to perform a considerable amount of work in hydraulic-engineering construction—for example, 40 percent of the earthmoving on the reconstruction of the White Sea-Baltic Canal, 50 percent in the building of the Tsimliansk Hydroelectric Power Plant, 81 percent on the Gorky Hydroelectric Power Plant, and 70 percent on the Kuibyshev Hydroelectric Power Plant. During the period 1945-54 the Mingechaur Dam was built by the hydraulic method; 14 million cu m of soil were deposited within its body.

In the USSR the scientific foundations for the technology of hydromechanical mining operations were established by N. D. Kholin, N. V. Mel’nikov, and G. A. Nurok. Theories of hydraulic monitor streams were proposed by G. A. Abramovich, G. N. Roer, G. M. Nikonov, and N. P. Gavyr-in. Technological schemes for hydromechanization at placer mines were developed by V. A. Florov, S. M. Shorokhov, G. M. Lezgintsev, and B. E. Fridman; at iron-ore pits and in hydraulic-engineering construction by S. B. Fogel’son, N. A. Lopatin, and B. M. Shkundin; in hydraulic irrigation and drainage operations by A. M. Tsarevskii; in railroad construction by N. P. D’iakov; and in underground coal mining by V. S. Muchnik.

The basic technological processes of hydromechanization include dislodging masses of rock (by means of hydraulic monitors, hydraulic dredging equipment, or nonpressurized streams of water), pressurized or nonpressurized hydraulic transport, terrace formation, piling up earth-fill installations (dikes or dams), and dressing the minerals. Water is supplied to hydraulic installations from rivers or lakes either directly, without reservoirs, or with the aid of water stored in reservoirs.

Hydraulic monitors are used in hydromechanization (primarily in open-pit mines), along with gravity-flow, pressurized, and combined gravity-flow-pressurized movement of hydraulic fill. Hydraulic dredging equipment is used in opening up quarries and in hydraulic-engineering construction. Hydraulic mining is carried out with subsequent wet dressing of the ores (using hydraulic classifiers, washing troughs, dressing sluices, magnetic separators, liquid cyclones, curved screens, and so on). Hydromechanization assures a smooth flow of the technological processes and lowers the capital expenditures and construction time for installations (as compared to the “dry” method of excavation). Complete automation of production processes is possible. However, the effective use of hydromechanization is limited by climatic conditions (early frosts during winter), by the properties of the rock in massifs (hard rock that is difficult to wash out considerably lowers the productivity of the hydraulic units), and by the availability of water resources.

Hydromechanization is being improved by creating heavy-duty, wear-resistant equipment for hydraulic transport with a productive capacity ranging from 10,000 to 15,000 cu m of rock per hour, by designing machinery for the excavation and crushing of hard rock that is difficult to wash out so that it may be transported hydraulically, and by developing new methods of piling that would allow a decrease in the area required for hydraulic piles.

Hydromechanization is used extensively in the national economy, principally in construction—earthmoving operations for filling in dams and dikes, constructing earth-fill embankments, and digging canals; excavating earth from construction pits and ditches; and dredging operations. It is also used in mining in stripping operations, extracting minerals at quarries and from the bottom of seas and oceans, in mine shafts, and in hydraulic transport of rock over long distances (sometimes several hundred kilometers). Hydromechanization is used effectively for relatively small projects in other branches of the economy as well—in agriculture (for cleaning irrigation canals, extracting and filling in fertile silt materials from lakes, delivering liquid fertilizers under pressure to the root system zone of plants); in the fishing industry (for unloading fish from nets and scows and transporting fish through pipes or chutes to fish-processing plants); at steam power plants (for hydraulic transport of ash and slag); and in bridge building (for excavating earth from caissons and construction pits).

REFERENCES

Tsarevskii, A. M. Gidromekhanizatsiia meliorativnykh rabot. Moscow, 1963.
Shorokhov, S. M. Razrabotka rossypnykh mestorozhdenii i osnovy proektirovaniia. Moscow, 1963.
Shkundin, B. M. Zemlesosnye snariady. Moscow, 1968.
Nurok, G. A. Gidromekhanizatsiia otkrytykh razrabotok. Moscow, 1970.

G. A. NUROK