Working of Mineral Deposits

the system of organizational and technical measures used to extract useful minerals from the earth’s interior. A distinction is made between the open-pit and underground methods of working mineral deposits.

Open-pit mining is used to extract solid minerals. The working of peat deposits is classified separately because of the special equipment and methods used.

In underground mining, the mineral is extracted from underground mining excavations or through wells. The wells are used to extract all liquid and gaseous minerals, as well as solid minerals when the deposit is worked by one of the physi-cochemical methods, such as underground solution, underground leaching, hydraulic well mining, or underground gasification of coal. Work is continuing on bacterial lixiviation, in which microorganisms are used to extract minerals.

Special methods are used to work deposits in the world ocean and extract useful minerals from seawater.

In the early 1970’s, more than 11 billion tons of solid minerals, some 3 billion tons of petroleum, and about 1,000 billion cu m of natural gas were extracted in the world each year. The world mining industry is growing at least 4–5 percent a year, with mineral extraction doubling approximately every 15–18 years. In terms of expenditures, 72 percent are used for the extraction of energy raw material, 21 percent for ores, and 7 percent for nonmetallic minerals.

The open-pit method is used to extract about 60 percent of the world’s metallic ores, 85 percent of the nonmetallic ores, 100 percent of the nonmetallic minerals, and some 35 percent of the coal. The underground method is used for minerals that lie at great depths.

A number of features are characteristic for the working of solid mineral deposits. Highly efficient mining enterprises are constructed, with pits yielding tens of millions of tons of various minerals annually and shafts and mines having capacities of several million tons. The deposits that are worked often contain low levels of useful components. Comprehensive use is made of minerals in working a deposit, for example, overburden rock is used in the construction industry. There is increased mining at

treat depths—hundreds of meters in the case of pits and several ilometers in the case of other mines. Cyclical-flow and flow work systems based on comprehensive mechanization and automation are being introduced. Production conditions and safety precautions are being improved. When mining work causes damage on or below the earth’s surface, corrective measures are taken. In the working of petroleum and gas deposits, progress is being made in introducing automated extraction systems and new methods of acting on productive layers, in order to extract the mineral more completely from the earth.